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ORGANIC SPECTROSCOPY

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DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO Ph.D

DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with GLENMARK LIFE SCIENCES LTD, Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 30 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, Dr T.V. Radhakrishnan and Dr B. K. Kulkarni, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 30 PLUS year tenure till date June 2021, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 9 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 90 Lakh plus views on dozen plus blogs, 233 countries, 7 continents, He makes himself available to all, contact him on +91 9323115463, email amcrasto@gmail.com, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 33 lakh plus views on New Drug Approvals Blog in 233 countries......https://newdrugapprovals.wordpress.com/ , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc

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RTS,S/AS01, RTS,S Mosquirix


 The World Health Organization (WHO) has announced that the Government of Malawi has immunized the first children with RTS,S/AS01 (RTS,S), the world’s first malaria vaccine, according to the World Record Academy.

Sequence:

1MMAPDPNANP NANPNANPNA NPNANPNANP NANPNANPNA NPNANPNANP51NANPNANPNA NPNANPNANP NANPNANPNA NPNKNNQGNG QGHNMPNDPN101RNVDENANAN NAVKNNNNEE PSDKHIEQYL KKIKNSISTE WSPCSVTCGN151GIQVRIKPGS ANKPKDELDY ENDIEKKICK MEKCSSVFNV VNSRPVTNME201NITSGFLGPL LVLQAGFFLL TRILTIPQSL DSWWTSLNFL GGSPVCLGQN251SQSPTSNHSP TSCPPICPGY RWMCLRRFII FLFILLLCLI FLLVLLDYQG301MLPVCPLIPG STTTNTGPCK TCTTPAQGNS MFPSCCCTKP TDGNCTCIPI351PSSWAFAKYL WEWASVRFSW LSLLVPFVQW FVGLSPTVWL SAIWMMWYWG401PSLYSIVSPF IPLLPIFFCL WVYI

RTS,S/AS01 (RTS,S)

RTS,S/AS01, Mosquirix

Cas 149121-47-1

203-400-Antigen CS (Plasmodium falciparum strain NF54 reduced), 203-L-methionine-204-L-methionine-205-L-alanine-206-L-proline-207-L-aspartic acid-210-L-alanine-211-L-asparagine-313-L-asparagine-329-L-glutamic acid-330-L-glutamine-333-L-lysine-336-L-lysine-339-L-isoleucine-373-L-glutamic acid-396-L-arginine-397-L-proline-398-L-valine-399-L-threonine-400-L-asparagine-, (400→1′)-protein with antigen (hepatitis B virus subtype adw small surface reduced) (9CI) 

Other Names

  • Malaria vaccine RTS,S
  • Mosquirix
  • RTS,S

Protein Sequence

Sequence Length: 424

An external file that holds a picture, illustration, etc. Object name is khvi-16-03-1669415-g002.jpg

Figure 2.

Graphical depiction of circumsporozoite (CSP) and RTS,S structures. CSP comprises an N-terminal region containing a signal peptide sequence and Region I that binds heparin sulfate proteoglycans and has embedded within it a conserved five amino acid (KLKQP) proteolytic cleavage site sequence; a central region containing four-amino acid (NANP/NVDP) repeats; and a C-terminal region containing Region II [a thrombospondin (TSP)-like domain] and a canonical glycosylphosphatidylinositol (GPI) anchor addition sequence. The region of the CSP included in the RTS,S vaccine includes the last 18 NANP repeats and C-terminus exclusive of the GPI anchor addition sequence. Hepatitis B virus surface antigen (HBsAg) monomers self-assemble into virus-like particles and approximately 25% of the HBsAg monomers in RTS,S are genetically fused to the truncated CSP and serve as protein carriers. The CSP fragment in RTS,S contains three known T-cell epitopes: a highly variable CD4 + T-cell epitope before the TSP-like domain (TH2R), a highly variable CD8 + T-cell epitope within the TSP-like domain (TH3R), and a conserved “universal” CD4 + T cell epitope (CS.T3) at the C-terminus. (Figure courtesy of a recent publication16 and open access,
PATENTWO 2009080715

https://patents.google.com/patent/WO2009080715A2/tr

XAMPLES

Example 1Recipe for component for a single pediatric dose of RTS, S malaria vaccine (2 vial formulation)Component AmountRTS,S 25μgNaCl 2.25mgPhosphate buffer (NaZK2) 1OmMMonothioglycerol 125μgWater for Injection Make volume to 250 μLThe above is prepared by adding RTS, S antigen to a mix of Water for Injection, NaCl 150OmM, phosphate buffer (NaZK2) 50OmM (pH 6.8 when diluted x 50) and an aqueous solution of monothioglycerol at 10%. Finally pH is adjusted to 7.0 ± 0.1.This may be provided as a vial together with a separate vial of adjuvant, for example a liposomal formulation of MPL and QS21Component Amount l,2-di-oleoyl-5/?-glycero-3-phosphocholine (DOPC) 500 μgCholesterol 125 μgMPL 25 μgQS21 25 μgNaCl 2.25mg Phosphate buffer (NaZK2) 1 OmMWater for Injection Make volume to250 μLFor administration the adjuvant formulation is added to the component formulation, for example using a syringe, and then shaken. Then the dose is administered in the usual way. The pH of the final liquid formulation is about 6.6 +/- 0.1.Example IAA final pediatric liquid formulation (1 vial) according to the invention may be prepared according to the following recipe.Component AmountRTS,S 25μgNaCl 4.5mgPhosphate buffer (NaZK2) 1OmMMonothioglycerol 125μg1 ,2-di-oleoyl-5/?-glycero-3-phosphocholine (DOPC) 500 μgCholesterol 125 μgMPL 25 μgQS21 25 μgWater for Injection Make volume to500 μLThe pH of the above liquid formulation is either adjusted to 7.0 +/- 0.1 (which is favorable for antigen stability, but not favorable at all for the MPL stability), or to 6.1 +/- 0.1 (which is favorable for MPL stability, but not favorable at all for RT S, S stability). Therefore this formulation is intended for rapid use after preparation.The above is prepared by adding RTS, S antigen to a mix of Water for Injection, NaCl 150OmM, phosphate buffer (NaZK2) 50OmM (pH 6.8 when diluted x 50) and an aqueous solution of monothioglycerol at 10%. Then a premix of liposomes containing MPL with QS21 is added, and finally pH is adjusted. Example IBA final adult dose (1 vial formulation) for the RTS, S according to the invention may be prepared as follows:Component AmountRTS,S 50μgNaCl 4.5mgPhosphate buffer (NaZK2) 1OmMMonothioglycerol 250μg1 ,2-di-oleoyl-5/?-glycero-3-phosphocholine (DOPC) 1000 μgCholesterol 250 μgMPL 50 μgQS21 50 μgWater for Injection Make volume to500 μLExample 1CExample 1C may prepared by putting Example 1, IA or IB in an amber vial, for example flushed with nitrogen before filing.

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WHO recommends groundbreaking malaria vaccine for children at risk

Historic RTS,S/AS01 recommendation can reinvigorate the fight against malaria6 October 2021https://www.who.int/news/item/06-10-2021-who-recommends-groundbreaking-malaria-vaccine-for-children-at-risk

The World Health Organization (WHO) is recommending widespread use of the RTS,S/AS01 (RTS,S) malaria vaccine among children in sub-Saharan Africa and in other regions with moderate to high P. falciparum malaria transmission. The recommendation is based on results from an ongoing pilot programme in Ghana, Kenya and Malawi that has reached more than 800 000 children since 2019.

“This is a historic moment. The long-awaited malaria vaccine for children is a breakthrough for science, child health and malaria control,” said WHO Director-General Dr Tedros Adhanom Ghebreyesus. “Using this vaccine on top of existing  tools to prevent malaria could save tens of thousands of young lives each year.”

Malaria remains a primary cause of childhood illness and death in sub-Saharan Africa. More than 260 000 African children under the age of five die from malaria annually.

In recent years, WHO and its partners have been reporting a stagnation in progress against the deadly disease.

“For centuries, malaria has stalked sub-Saharan Africa, causing immense personal suffering,” said Dr Matshidiso Moeti, WHO Regional Director for Africa. “We have long hoped for an effective malaria vaccine and now for the first time ever, we have such a vaccine recommended for widespread use. Today’s recommendation offers a glimmer of hope for the continent which shoulders the heaviest burden of the disease and we expect many more African children to be protected from malaria and grow into healthy adults.”

WHO recommendation for the RTS,S malaria vaccine

Based on the advice of two WHO global advisory bodies, one for immunization and the other for malaria, the Organization recommends that:

WHO recommends that in the context of comprehensive malaria control the RTS,S/AS01 malaria vaccine be used for the prevention of P. falciparum malaria in children living in regions with moderate to high transmission as defined by WHO.  RTS,S/AS01 malaria vaccine should be provided in a schedule of 4 doses in children from 5 months of age for the reduction of malaria disease and burden.

Summary of key findings of the malaria vaccine pilots

Key findings of the pilots informed the recommendation based on data and insights generated from two years of vaccination in child health clinics in the three pilot countries, implemented under the leadership of the Ministries of Health of Ghana, Kenya and Malawi. Findings include:

  • Feasible to deliver: Vaccine introduction is feasible, improves health and saves lives, with good and equitable coverage of RTS,S seen through routine immunization systems. This occurred even in the context of the COVID-19 pandemic.
  • Reaching the unreached: RTS,S increases equity in access to malaria prevention.
    • Data from the pilot programme showed that more than two-thirds of children in the 3 countries who are not sleeping under a bednet are benefitting from the RTS,S vaccine.
    • Layering the tools results in over 90% of children benefitting from at least one preventive intervention (insecticide treated bednets or the malaria vaccine).
  • Strong safety profile: To date, more than 2.3 million doses of the vaccine have been administered in 3 African countries – the vaccine has a favorable safety profile.
  • No negative impact on uptake of bednets, other childhood vaccinations, or health seeking behavior for febrile illness. In areas where the vaccine has been introduced, there has been no decrease in the use of insecticide-treated nets, uptake of other childhood vaccinations or health seeking behavior for febrile illness.
  • High impact in real-life childhood vaccination settings: Significant reduction (30%) in deadly severe malaria, even when introduced in areas where insecticide-treated nets are widely used and there is good access to diagnosis and treatment.
  • Highly cost-effective: Modelling estimates that the vaccine is cost effective in areas of moderate to high malaria transmission.

Next steps for the WHO-recommended malaria vaccine will include funding decisions from the global health community for broader rollout, and country decision-making on whether to adopt the vaccine as part of national malaria control strategies.

Financial support

Financing for the pilot programme has been mobilized through an unprecedented collaboration among three key global health funding bodies: Gavi, the Vaccine Alliance; the Global Fund to Fight AIDS, Tuberculosis and Malaria; and Unitaid.

Note to editors:

  • The malaria vaccine, RTS,S, acts against P. falciparum, the most deadly malaria parasite globally, and the most prevalent in Africa.
  • The Malaria Vaccine Implementation Programme is generating evidence and experience on the feasibility, impact and safety of the RTS,S malaria vaccine in real-life, routine settings in selected areas of Ghana, Kenya and Malawi.
  • Pilot malaria vaccine introductions are led by the Ministries of Health of Ghana, Kenya and Malawi.
  • The pilot programme will continue in the 3 pilot countries to understand the added value of the 4th vaccine dose, and to measure longer-term impact on child deaths.
  • The Malaria Vaccine Implementation Programme is coordinated by WHO and supported by in-country and international partners, including PATH, UNICEF and GSK, which is donating up to 10 million doses of the vaccine for the pilot.
  • The RTS,S malaria vaccine is the result of 30 years of research and development by GSK and through a partnership with PATH, with support from a network of African research centres.
  • The Bill & Melinda Gates Foundation provided catalytic funding for late-stage development of RTS,S between 2001 and 2015.

RTS,S/AS01 (trade name Mosquirix) is a recombinant protein-based malaria vaccine. In October 2021, the vaccine was endorsed by the World Health Organization (WHO) for “broad use” in children, making it the first malaria vaccine candidate, and first vaccine to address parasitic infection, to receive this recommendation.[3][4][5]

The RTS,S vaccine was conceived of and created in the late 1980s by scientists working at SmithKline Beecham Biologicals (now GlaxoSmithKline (GSK) Vaccines) laboratories in Belgium.[6] The vaccine was further developed through a collaboration between GSK and the Walter Reed Army Institute of Research in the U.S. state of Maryland[7] and has been funded in part by the PATH Malaria Vaccine Initiative and the Bill and Melinda Gates Foundation. Its efficacy ranges from 26 to 50% in infants and young children.

Approved for use by the European Medicines Agency (EMA) in July 2015,[1] it is the world’s first licensed malaria vaccine and also the first vaccine licensed for use against a human parasitic disease of any kind.[8] On 23 October 2015, WHO’s Strategic Advisory Group of Experts on Immunization (SAGE) and the Malaria Policy Advisory Committee (MPAC) jointly recommended a pilot implementation of the vaccine in Africa.[9] This pilot project for vaccination was launched on 23 April 2019 in Malawi, on 30 April 2019 in Ghana, and on 13 September 2019 in Kenya.[10][11]

Background

Main article: Malaria vaccine

Potential malaria vaccines have been an intense area of research since the 1960s.[12] SPf66 was tested extensively in endemic areas in the 1990s, but clinical trials showed it to be insufficiently effective.[13] Other vaccine candidates, targeting the blood-stage of the malaria parasite’s life cycle, have also been insufficient on their own.[14] Among several potential vaccines under development that target the pre-erythrocytic stage of the disease, RTS,S has shown the most promising results so far.[15]

Approval history

The EMA approved the RTS,S vaccine in July 2015, with a recommendation that it be used in Africa for babies at risk of getting malaria. RTS,S was the world’s first malaria vaccine to get approval for this use.[16][8] Preliminary research suggests that delayed fractional dosing could increase the vaccine’s efficacy up to 86%.[17][18]

On 17 November 2016, WHO announced that the RTS,S vaccine would be rolled out in pilot projects in three countries in sub-Saharan Africa. The pilot program, coordinated by WHO, will assess the extent to which the vaccine’s protective effect shown in advanced clinical trials can be replicated in real-life settings. Specifically, the programme will evaluate the feasibility of delivering the required four doses of the vaccine; the impact of the vaccine on lives saved; and the safety of the vaccine in the context of routine use.[19]

Vaccinations by the ministries of health of Malawi, Ghana, and Kenya began in April and September 2019 and target 360,000 children per year in areas where vaccination would have the highest impact. The results are planned to be used by the World Health Organization to advise about a possible future deployment of the vaccine.[10][11][20] In 2021 it was reported that the vaccine together with other anti-malaria medication when given at the most vulnerable season could reduce deaths and illness from the disease by 70%.[21][22]

Funding

RTS,S has been funded, most recently, by the non-profit PATH Malaria Vaccine Initiative (MVI) and GlaxoSmithKline with funding from the Bill and Melinda Gates Foundation.[23] The RTS,S-based vaccine formulation had previously been demonstrated to be safe, well tolerated, immunogenic, and to potentially confer partial efficacy in both malaria-naive and malaria-experienced adults as well as children.[24]

Components and mechanism

 

The RTS,S vaccine is based on a protein construct first developed by GlaxoSmithKline in 1986. It was named RTS because it was engineered using genes from the repeat (‘R’) and T-cell epitope (‘T’) of the pre-erythrocytic circumsporozoite protein (CSP) of the Plasmodium falciparum malaria parasite together with a viral surface antigen (‘S’) of the hepatitis B virus (HBsAg).[7] This protein was then mixed with additional HBsAg to improve purification, hence the extra “S”.[7] Together, these two protein components assemble into soluble virus-like particles similar to the outer shell of a hepatitis B virus.[25]

A chemical adjuvant (AS01, specifically AS01E) was added to increase the immune system response.[26] Infection is prevented by inducing humoral and cellular immunity, with high antibody titers, that block the parasite from infecting the liver.[27]

The T-cell epitope of CSP is O-fucosylated in Plasmodium falciparum[28][29] and Plasmodium vivax,[30] while the RTS,S vaccine produced in yeast is not.

References

  1. Jump up to:a b “Mosquirix H-W-2300”European Medicines Agency (EMA). Retrieved 4 March 2021.
  2. ^ “RTS,S Malaria Vaccine: 2019 Partnership Award Honoree”YouTube. Global Health Technologies Coalition. Retrieved 6 October 2021.
  3. ^ Davies L (6 October 2021). “WHO endorses use of world’s first malaria vaccine in Africa”The Guardian. Retrieved 6 October2021.
  4. ^ Drysdale C, Kelleher K. “WHO recommends groundbreaking malaria vaccine for children at risk” (Press release). Geneva: World Health Organization. Retrieved 6 October 2021.
  5. ^ Mandavilli A (6 October 2021). “A ‘Historical Event’: First Malaria Vaccine Approved by W.H.O.” New York Times. Retrieved 6 October 2021.
  6. ^ “HYBRID PROTEIN BETWEEN CS FROM PLASMODIUM AND HBsAG”.
  7. Jump up to:a b c Heppner DG, Kester KE, Ockenhouse CF, Tornieporth N, Ofori O, Lyon JA, et al. (March 2005). “Towards an RTS,S-based, multi-stage, multi-antigen vaccine against falciparum malaria: progress at the Walter Reed Army Institute of Research”Vaccine23 (17–18): 2243–50. doi:10.1016/j.vaccine.2005.01.142PMID 15755604Archived from the original on 23 July 2018.
  8. Jump up to:a b Walsh F (24 July 2015). “Malaria vaccine gets ‘green light'”BBC NewsArchived from the original on 21 July 2020. Retrieved 25 July 2015.
  9. ^ Stewart S (23 October 2015). “Pilot implementation of first malaria vaccine recommended by WHO advisory groups” (Press release). Geneva: World Health OrganizationArchived from the original on 19 September 2021.
  10. Jump up to:a b Alonso P (19 June 2019). “Letter to partners – June 2019”(Press release). Wuxi: World Health Organization. Retrieved 22 October 2019.
  11. Jump up to:a b “Malaria vaccine launched in Kenya: Kenya joins Ghana and Malawi to roll out landmark vaccine in pilot introduction” (Press release). Homa Bay: World Health Organization. 13 September 2019. Retrieved 22 October 2019.
  12. ^ Hill AV (October 2011). “Vaccines against malaria”Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences366 (1579): 2806–14. doi:10.1098/rstb.2011.0091PMC 3146776PMID 21893544.
  13. ^ Graves P, Gelband H (April 2006). Graves PM (ed.). “Vaccines for preventing malaria (SPf66)”The Cochrane Database of Systematic Reviews (2): CD005966. doi:10.1002/14651858.CD005966PMC 6532709PMID 16625647.
  14. ^ Graves P, Gelband H (October 2006). Graves PM (ed.). “Vaccines for preventing malaria (blood-stage)”The Cochrane Database of Systematic Reviews (4): CD006199. doi:10.1002/14651858.CD006199PMC 6532641PMID 17054281.
  15. ^ Graves P, Gelband H (October 2006). Graves PM (ed.). “Vaccines for preventing malaria (pre-erythrocytic)”The Cochrane Database of Systematic Reviews (4): CD006198. doi:10.1002/14651858.CD006198PMC 6532586PMID 17054280.
  16. ^ “First malaria vaccine receives positive scientific opinion from EMA”European Medicines Agency. 24 July 2015. Retrieved 24 July 2015.
  17. ^ Birkett A (16 September 2016). “A vaccine for malaria elimination?”PATH.
  18. ^ Regules JA, Cicatelli SB, Bennett JW, Paolino KM, Twomey PS, Moon JE, et al. (September 2016). “Fractional Third and Fourth Dose of RTS,S/AS01 Malaria Candidate Vaccine: A Phase 2a Controlled Human Malaria Parasite Infection and Immunogenicity Study”The Journal of Infectious Diseases214 (5): 762–71. doi:10.1093/infdis/jiw237PMID 27296848.
  19. ^ “Malaria: The malaria vaccine implementation programme (MVIP)”.
  20. ^ “WHO | MVIP countries: Ghana, Kenya and Malawi”.
  21. ^ Chandramohan D, Zongo I, Sagara I, Cairns M, Yerbanga RS, Diarra M, et al. (September 2021). “Seasonal Malaria Vaccination with or without Seasonal Malaria Chemoprevention”The New England Journal of Medicine385 (11): 1005–1017. doi:10.1056/NEJMoa2026330PMID 34432975.
  22. ^ Roxby P (26 August 2021). “Trial suggests malaria sickness could be cut by 70%”BBC NewsArchived from the original on 3 October 2021. Retrieved 26 August 2021.
  23. ^ Stein R (18 October 2011). “Experimental malaria vaccine protects many children, study shows”Washington Post.
  24. ^ Regules JA, Cummings JF, Ockenhouse CF (May 2011). “The RTS,S vaccine candidate for malaria”Expert Review of Vaccines10 (5): 589–99. doi:10.1586/erv.11.57PMID 21604980S2CID 20443829.
  25. ^ Rutgers T, Gordon D, Gathoye AM, Hollingdale M, Hockmeyer W, Rosenberg M, De Wilde M (September 1988). “Hepatitis B Surface Antigen as Carrier Matrix for the Repetitive Epitope of the Circumsporozoite Protein of Plasmodium Falciparum”Nature Biotechnology6 (9): 1065–1070. doi:10.1038/nbt0988-1065S2CID 39880644.
  26. ^ RTS,S Clinical Trials Partnership (July 2015). “Efficacy and safety of RTS,S/AS01 malaria vaccine with or without a booster dose in infants and children in Africa: final results of a phase 3, individually randomised, controlled trial”Lancet386 (9988): 31–45. doi:10.1016/S0140-6736(15)60721-8PMC 5626001PMID 25913272.
  27. ^ Foquet L, Hermsen CC, van Gemert GJ, Van Braeckel E, Weening KE, Sauerwein R, et al. (January 2014). “Vaccine-induced monoclonal antibodies targeting circumsporozoite protein prevent Plasmodium falciparum infection”The Journal of Clinical Investigation124 (1): 140–4. doi:10.1172/JCI70349PMC 3871238PMID 24292709.
  28. ^ Swearingen KE, Lindner SE, Shi L, Shears MJ, Harupa A, Hopp CS, et al. (April 2016). “Interrogating the Plasmodium Sporozoite Surface: Identification of Surface-Exposed Proteins and Demonstration of Glycosylation on CSP and TRAP by Mass Spectrometry-Based Proteomics”PLOS Pathogens12 (4): e1005606. doi:10.1371/journal.ppat.1005606PMC 4851412PMID 27128092.
  29. ^ Lopaticki S, Yang AS, John A, Scott NE, Lingford JP, O’Neill MT, et al. (September 2017). “Protein O-fucosylation in Plasmodium falciparum ensures efficient infection of mosquito and vertebrate hosts”Nature Communications8 (1): 561. Bibcode:2017NatCo…8..561Ldoi:10.1038/s41467-017-00571-yPMC 5601480PMID 28916755.
  30. ^ Swearingen KE, Lindner SE, Flannery EL, Vaughan AM, Morrison RD, Patrapuvich R, et al. (July 2017). “Proteogenomic analysis of the total and surface-exposed proteomes of Plasmodium vivax salivary gland sporozoites”PLOS Neglected Tropical Diseases11 (7): e0005791. doi:10.1371/journal.pntd.0005791PMC 5552340PMID 28759593.

Further reading

  • Wilby KJ, Lau TT, Gilchrist SE, Ensom MH (March 2012). “Mosquirix (RTS,S): a novel vaccine for the prevention of Plasmodium falciparum malaria”. The Annals of Pharmacotherapy46 (3): 384–93. doi:10.1345/aph.1Q634PMID 22408046.
  • Asante KP, Abdulla S, Agnandji S, Lyimo J, Vekemans J, Soulanoudjingar S, et al. (October 2011). “Safety and efficacy of the RTS,S/AS01E candidate malaria vaccine given with expanded-programme-on-immunisation vaccines: 19 month follow-up of a randomised, open-label, phase 2 trial”. The Lancet. Infectious Diseases11 (10): 741–9. doi:10.1016/S1473-3099(11)70100-1PMID 21782519.

External links

Vaccine description
TargetP. falciparum; to a lesser extent Hepatitis B
Vaccine typeProtein subunit
Clinical data
Trade namesMosquirix
Routes of
administration
intramuscular injection (0.5 mL)[1]
Legal status
Legal statusIn general: ℞ (Prescription only)

A poster advertising trials of the RTS,S vaccine[2]

malaria vaccine is a vaccine that is used to prevent malaria. The only approved vaccine as of 2021, is RTS,S, known by the brand name Mosquirix.[1] It requires four injections.[1]

Research continues with other malaria vaccines. The most effective malaria vaccine is R21/Matrix-M, with a 77% efficacy rate shown in initial trials, and significantly higher antibody levels than with the RTS,S vaccine.[2] It is the first vaccine that meets the World Health Organization‘s (WHO) goal of a malaria vaccine with at least 75% efficacy.[3][2]

Approved vaccines

RTS,S

Main article: RTS,S

RTS,S (developed by PATH Malaria Vaccine Initiative (MVI) and GlaxoSmithKline (GSK) with support from the Bill and Melinda Gates Foundation) is the most recently developed recombinant vaccine. It consists of the P. falciparum circumsporozoite protein (CSP) from the pre-erythrocytic stage. The CSP antigen causes the production of antibodies capable of preventing the invasion of hepatocytes and additionally elicits a cellular response enabling the destruction of infected hepatocytes. The CSP vaccine presented problems in the trial stage, due to its poor immunogenicity. RTS,S attempted to avoid these by fusing the protein with a surface antigen from hepatitis B, hence creating a more potent and immunogenic vaccine. When tested in trials an emulsion of oil in water and the added adjuvants of monophosphoryl A and QS21 (SBAS2), the vaccine gave protective immunity to 7 out of 8 volunteers when challenged with P. falciparum.[4]

RTS,S/AS01 (commercial name Mosquirix),[5] was engineered using genes from the outer protein of P. falciparum malaria parasite and a portion of a hepatitis B virus plus a chemical adjuvant to boost the immune response. Infection is prevented by inducing high antibody titers that block the parasite from infecting the liver.[6] In November 2012, a Phase III trial of RTS,S found that it provided modest protection against both clinical and severe malaria in young infants.[7]

As of October 2013, preliminary results of a Phase III clinical trial indicated that RTS,S/AS01 reduced the number of cases among young children by almost 50 percent and among infants by around 25 percent. The study ended in 2014. The effects of a booster dose were positive, even though overall efficacy seems to wane with time. After four years reductions were 36 percent for children who received three shots and a booster dose. Missing the booster dose reduced the efficacy against severe malaria to a negligible effect. The vaccine was shown to be less effective for infants. Three doses of vaccine plus a booster reduced the risk of clinical episodes by 26 percent over three years, but offered no significant protection against severe malaria.[8]

In a bid to accommodate a larger group and guarantee a sustained availability for the general public, GSK applied for a marketing license with the European Medicines Agency (EMA) in July 2014.[9] GSK treated the project as a non-profit initiative, with most funding coming from the Gates Foundation, a major contributor to malaria eradication.[10]

On 24 July 2015, Mosquirix received a positive opinion from the European Medicines Agency (EMA) on the proposal for the vaccine to be used to vaccinate children aged 6 weeks to 17 months outside the European Union.[11][12][1] A pilot project for vaccination was launched on 23 April 2019, in Malawi, on 30 April 2019, in Ghana, and on 13 September 2019, in Kenya.[13][14]

In October 2021, the vaccine was endorsed by the World Health Organization for “broad use” in children, making it the first malaria vaccine to receive this recommendation.[15][16][17]

Agents under development

A completely effective vaccine is not available for malaria, although several vaccines are under development. Multiple vaccine candidates targeting the blood-stage of the parasite’s life cycle have been insufficient on their own.[18] Several potential vaccines targeting the pre-erythrocytic stage are being developed, with RTS,S the only approved option so far.[19][7]

R21/Matrix-M

The most effective malaria vaccine is R21/Matrix-M, with 77% efficacy shown in initial trials. It is the first vaccine that meets the World Health Organization’s goal of a malaria vaccine with at least 75% efficacy.[3] It was developed through a collaboration involving the University of Oxford, the Kenya Medical Research Institute, the London School of Hygiene & Tropical MedicineNovavax, the Serum Institute of India, and the Institut de Recherche en Sciences de la Santé in NanoroBurkina Faso. The R21 vaccine uses a circumsporozoite protein (CSP) antigen, at a higher proportion than the RTS,S vaccine. It includes the Matrix-M adjuvant that is also utilized in the Novavax COVID-19 vaccine.[20]

A Phase II trial was reported in April 2021, with a vaccine efficacy of 77% and antibody levels significantly higher than with the RTS,S vaccine. A Phase III trial is planned with 4,800 children across four African countries. If the vaccine is approved, over 200 million doses can be manufactured annually by the Serum Institute of India.[2]

Nanoparticle enhancement of RTS,S

In 2015, researchers used a repetitive antigen display technology to engineer a nanoparticle that displayed malaria specific B cell and T cell epitopes. The particle exhibited icosahedral symmetry and carried on its surface up to 60 copies of the RTS,S protein. The researchers claimed that the density of the protein was much higher than the 14% of the GSK vaccine.[21][22]

PfSPZ vaccine

Main article: PfSPZ Vaccine

The PfSPZ vaccine is a candidate malaria vaccine developed by Sanaria using radiation-attenuated sporozoites to elicit an immune response. Clinical trials have been promising, with trials taking place in Africa, Europe, and the US protecting over 80% of volunteers.[23] It has been subject to some criticism regarding the ultimate feasibility of large-scale production and delivery in Africa, since it must be stored in liquid nitrogen.

The PfSPZ vaccine candidate was granted fast track designation by the U.S. Food and Drug Administration in September 2016.[24]

In April 2019, a phase 3 trial in Bioko was announced, scheduled to start in early 2020.[25]

saRNA vaccine against PMIF

A patent was published in February 2021 for a Self-amplifying RNA (saRNA) vaccine that targets the protein PMIF, which is produced by the plasmodium parasite to inhibit the body’s T-cell response. The vaccine has been tested in mice and is described as, “probably the highest level of protection that has been seen in a mouse model” according to Richard Bucala, co-inventor of the vaccine. There are plans for phase one tests in humans later in 2021.[26]

Other developments

  • SPf66 is a synthetic peptide based vaccine developed by Manuel Elkin Patarroyo team in Colombia, and was tested extensively in endemic areas in the 1990s. Clinical trials showed it to be insufficiently effective, with 28% efficacy in South America and minimal or no efficacy in Africa.[27]
  • The CSP (Circum-Sporozoite Protein) was a vaccine developed that initially appeared promising enough to undergo trials. It is also based on the circumsporozoite protein, but additionally has the recombinant (Asn-Ala-Pro15Asn-Val-Asp-Pro)2-Leu-Arg(R32LR) protein covalently bound to a purified Pseudomonas aeruginosa toxin (A9). However at an early stage a complete lack of protective immunity was demonstrated in those inoculated. The study group used in Kenya had an 82% incidence of parasitaemia whilst the control group only had an 89% incidence. The vaccine intended to cause an increased T-lymphocyte response in those exposed, this was also not observed.[citation needed]
  • The NYVAC-Pf7 multi-stage vaccine attempted to use different technology, incorporating seven P.falciparum antigenic genes. These came from a variety of stages during the life cycle. CSP and sporozoite surface protein 2 (called PfSSP2) were derived from the sporozoite phase. The liver stage antigen 1 (LSA1), three from the erythrocytic stage (merozoite surface protein 1, serine repeat antigen and AMA-1) and one sexual stage antigen (the 25-kDa Pfs25) were included. This was first investigated using Rhesus monkeys and produced encouraging results: 4 out of the 7 antigens produced specific antibody responses (CSP, PfSSP2, MSP1 and PFs25). Later trials in humans, despite demonstrating cellular immune responses in over 90% of the subjects, had very poor antibody responses. Despite this following administration of the vaccine some candidates had complete protection when challenged with P.falciparum. This result has warranted ongoing trials.[citation needed]
  • In 1995 a field trial involving [NANP]19-5.1 proved to be very successful. Out of 194 children vaccinated none developed symptomatic malaria in the 12-week follow up period and only 8 failed to have higher levels of antibody present. The vaccine consists of the schizont export protein (5.1) and 19 repeats of the sporozoite surface protein [NANP]. Limitations of the technology exist as it contains only 20% peptide and has low levels of immunogenicity. It also does not contain any immunodominant T-cell epitopes.[28]
  • A chemical compound undergoing trials for treatment of tuberculosis and cancer—the JmJc inhibitor ML324 and the antitubercular clinical candidate SQ109—is potentially a new line of drugs to treat malaria and kill the parasite in its infectious stage. More tests still need to be carried out before the compounds would be approved as a viable treatment.[29]

Considerations

The task of developing a preventive vaccine for malaria is a complex process. There are a number of considerations to be made concerning what strategy a potential vaccine should adopt.

Parasite diversity

P. falciparum has demonstrated the capability, through the development of multiple drug-resistant parasites, for evolutionary change. The Plasmodium species has a very high rate of replication, much higher than that actually needed to ensure transmission in the parasite’s life cycle. This enables pharmaceutical treatments that are effective at reducing the reproduction rate, but not halting it, to exert a high selection pressure, thus favoring the development of resistance. The process of evolutionary change is one of the key considerations necessary when considering potential vaccine candidates. The development of resistance could cause a significant reduction in efficacy of any potential vaccine thus rendering useless a carefully developed and effective treatment.[30]

Choosing to address the symptom or the source

The parasite induces two main response types from the human immune system. These are anti-parasitic immunity and anti-toxic immunity.

  • “Anti-parasitic immunity” addresses the source; it consists of an antibody response (humoral immunity) and a cell-mediated immune response. Ideally a vaccine would enable the development of anti-plasmodial antibodies in addition to generating an elevated cell-mediated response. Potential antigens against which a vaccine could be targeted will be discussed in greater depth later. Antibodies are part of the specific immune response. They exert their effect by activating the complement cascade, stimulating phagocytic cells into endocytosis through adhesion to an external surface of the antigenic substances, thus ‘marking’ it as offensive. Humoral or cell-mediated immunity consists of many interlinking mechanisms that essentially aim to prevent infection entering the body (through external barriers or hostile internal environments) and then kill any micro-organisms or foreign particles that succeed in penetration. The cell-mediated component consists of many white blood cells (such as monocytesneutrophilsmacrophageslymphocytesbasophilsmast cellsnatural killer cells, and eosinophils) that target foreign bodies by a variety of different mechanisms. In the case of malaria both systems would be targeted to attempt to increase the potential response generated, thus ensuring the maximum chance of preventing disease.[citation needed]
  • “Anti-toxic immunity” addresses the symptoms; it refers to the suppression of the immune response associated with the production of factors that either induce symptoms or reduce the effect that any toxic by-products (of micro-organism presence) have on the development of disease. For example, it has been shown that Tumor necrosis factor-alpha has a central role in generating the symptoms experienced in severe P. falciparum malaria. Thus a therapeutic vaccine could target the production of TNF-a, preventing respiratory distress and cerebral symptoms. This approach has serious limitations as it would not reduce the parasitic load; rather it only reduces the associated pathology. As a result, there are substantial difficulties in evaluating efficacy in human trials.

Taking this information into consideration an ideal vaccine candidate would attempt to generate a more substantial cell-mediated and antibody response on parasite presentation. This would have the benefit of increasing the rate of parasite clearance, thus reducing the experienced symptoms and providing a level of consistent future immunity against the parasite.

Potential targets

See also: PfSPZ Vaccine

Parasite stageTarget
SporozoiteHepatocyte invasion; direct anti-sporozite
HepatozoiteDirect anti-hepatozoite.
Asexual erythrocyticAnti-host erythrocyte, antibodies blocking invasion; anti receptor ligand, anti-soluble toxin
GametocytesAnti-gametocyte. Anti-host erythrocyte, antibodies blocking fertilisation, antibodies blocking egress from the mosquito midgut.

By their very nature, protozoa are more complex organisms than bacteria and viruses, with more complicated structures and life cycles. This presents problems in vaccine development but also increases the number of potential targets for a vaccine. These have been summarised into the life cycle stage and the antibodies that could potentially elicit an immune response.

The epidemiology of malaria varies enormously across the globe, and has led to the belief that it may be necessary to adopt very different vaccine development strategies to target the different populations. A Type 1 vaccine is suggested for those exposed mostly to P. falciparum malaria in sub-Saharan Africa, with the primary objective to reduce the number of severe malaria cases and deaths in infants and children exposed to high transmission rates. The Type 2 vaccine could be thought of as a ‘travellers’ vaccine’, aiming to prevent all cases of clinical symptoms in individuals with no previous exposure. This is another major public health problem, with malaria presenting as one of the most substantial threats to travellers’ health. Problems with the available pharmaceutical therapies include costs, availability, adverse effects and contraindications, inconvenience and compliance, many of which would be reduced or eliminated entirely if an effective (greater than 85–90%) vaccine was developed.[citation needed]

The life cycle of the malaria parasite is particularly complex, presenting initial developmental problems. Despite the huge number of vaccines available, there are none that target parasitic infections. The distinct developmental stages involved in the life cycle present numerous opportunities for targeting antigens, thus potentially eliciting an immune response. Theoretically, each developmental stage could have a vaccine developed specifically to target the parasite. Moreover, any vaccine produced would ideally have the ability to be of therapeutic value as well as preventing further transmission and is likely to consist of a combination of antigens from different phases of the parasite’s development. More than 30 of these antigens are being researched[when?] by teams all over the world in the hope of identifying a combination that can elicit immunity in the inoculated individual. Some of the approaches involve surface expression of the antigen, inhibitory effects of specific antibodies on the life cycle and the protective effects through immunization or passive transfer of antibodies between an immune and a non-immune host. The majority of research into malarial vaccines has focused on the Plasmodium falciparum strain due to the high mortality caused by the parasite and the ease of a carrying out in vitro/in vivo studies. The earliest vaccines attempted to use the parasitic circumsporozoite protein (CSP). This is the most dominant surface antigen of the initial pre-erythrocytic phase. However, problems were encountered due to low efficacy, reactogenicity and low immunogenicity.[citation needed]

  • The initial stage in the life cycle, following inoculation, is a relatively short “pre-erythrocytic” or “hepatic” phase. A vaccine at this stage must have the ability to protect against sporozoites invading and possibly inhibiting the development of parasites in the hepatocytes (through inducing cytotoxic T-lymphocytes that can destroy the infected liver cells). However, if any sporozoites evaded the immune system they would then have the potential to be symptomatic and cause the clinical disease.
  • The second phase of the life cycle is the “erythrocytic” or blood phase. A vaccine here could prevent merozoite multiplication or the invasion of red blood cells. This approach is complicated by the lack of MHC molecule expression on the surface of erythrocytes. Instead, malarial antigens are expressed, and it is this towards which the antibodies could potentially be directed. Another approach would be to attempt to block the process of erythrocyte adherence to blood vessel walls. It is thought that this process is accountable for much of the clinical syndrome associated with malarial infection; therefore a vaccine given during this stage would be therapeutic and hence administered during clinical episodes to prevent further deterioration.
  • The last phase of the life cycle that has the potential to be targeted by a vaccine is the “sexual stage”. This would not give any protective benefits to the individual inoculated but would prevent further transmission of the parasite by preventing the gametocytes from producing multiple sporozoites in the gut wall of the mosquito. It therefore would be used as part of a policy directed at eliminating the parasite from areas of low prevalence or to prevent the development and spread of vaccine-resistant parasites. This type of transmission-blocking vaccine is potentially very important. The evolution of resistance in the malaria parasite occurs very quickly, potentially making any vaccine redundant within a few generations. This approach to the prevention of spread is therefore essential.
  • Another approach is to target the protein kinases, which are present during the entire lifecycle of the malaria parasite. Research is underway on this, yet production of an actual vaccine targeting these protein kinases may still take a long time.[31]
  • Report of a vaccine candidate capable to neutralize all tested strains of Plasmodium falciparum, the most deadly form of the parasite causing malaria, was published in Nature Communications by a team of scientists from the University of Oxford in 2011.[32] The viral vector vaccine, targeting a full-length P. falciparum reticulocyte-binding protein homologue 5 (PfRH5) was found to induce an antibody response in an animal model. The results of this new vaccine confirmed the utility of a key discovery reported from scientists at the Wellcome Trust Sanger Institute, published in Nature.[33] The earlier publication reported P. falciparum relies on a red blood cell surface receptor, known as ‘basigin’, to invade the cells by binding a protein PfRH5 to the receptor.[33] Unlike other antigens of the malaria parasite which are often genetically diverse, the PfRH5 antigen appears to have little genetic diversity. It was found to induce very low antibody response in people naturally exposed to the parasite.[32] The high susceptibility of PfRH5 to the cross-strain neutralizing vaccine-induced antibody demonstrated a significant promise for preventing malaria in the long and often difficult road of vaccine development. According to Professor Adrian Hill, a Wellcome Trust Senior Investigator at the University of Oxford, the next step would be the safety tests of this vaccine. At the time (2011) it was projected that if these proved successful, the clinical trials in patients could begin within two to three years.[34]
  • PfEMP1, one of the proteins known as variant surface antigens (VSAs) produced by Plasmodium falciparum, was found to be a key target of the immune system’s response against the parasite. Studies of blood samples from 296 mostly Kenyan children by researchers of Burnet Institute and their cooperators showed that antibodies against PfEMP1 provide protective immunity, while antibodies developed against other surface antigens do not. Their results demonstrated that PfEMP1 could be a target to develop an effective vaccine which will reduce risk of developing malaria.[35][36]
  • Plasmodium vivax is the common malaria species found in India, Southeast Asia and South America. It is able to stay dormant in the liver and reemerge years later to elicit new infections. Two key proteins involved in the invasion of the red blood cells (RBC) by P. vivax are potential targets for drug or vaccine development. When the Duffy binding protein (DBP) of P. vivax binds the Duffy antigen (DARC) on the surface of RBC, process for the parasite to enter the RBC is initiated. Structures of the core region of DARC and the receptor binding pocket of DBP have been mapped by scientists at the Washington University in St. Louis. The researchers found that the binding is a two-step process which involves two copies of the parasite protein acting together like a pair of tongs which “clamp” two copies of DARC. Antibodies that interfere with the binding, by either targeting the key region of the DARC or the DBP will prevent the infection.[37][38]
  • Antibodies against the Schizont Egress Antigen-1 (PfSEA-1) were found to disable the parasite ability to rupture from the infected red blood cells (RBCs) thus prevent it from continuing with its life cycle. Researchers from Rhode Island Hospital identified Plasmodium falciparum PfSEA-1, a 244 kd malaria antigen expressed in the schizont-infected RBCs. Mice vaccinated with the recombinant PfSEA-1 produced antibodies which interrupted the schizont rupture from the RBCs and decreased the parasite replication. The vaccine protected the mice from lethal challenge of the parasite. Tanzanian and Kenyan children who have antibodies to PfSEA-1 were found to have fewer parasites in their blood stream and milder case of malaria. By blocking the schizont outlet, the PfSEA-1 vaccine may work synergistically with vaccines targeting the other stages of the malaria life cycle such as hepatocyte and RBC invasion.[39][40]

Mix of antigenic components

Increasing the potential immunity generated against Plasmodia can be achieved by attempting to target multiple phases in the life cycle. This is additionally beneficial in reducing the possibility of resistant parasites developing. The use of multiple-parasite antigens can therefore have a synergistic or additive effect.

One of the most successful vaccine candidates in clinical trials[which?][when?] consists of recombinant antigenic proteins to the circumsporozoite protein.[41] (This is discussed in more detail below.)[where?]

Delivery system

 

The selection of an appropriate system is fundamental in all vaccine development, but especially so in the case of malaria. A vaccine targeting several antigens may require delivery to different areas and by different means in order to elicit an effective response. Some adjuvants can direct the vaccine to the specifically targeted cell type—e.g. the use of Hepatitis B virus in the RTS,S vaccine to target infected hepatocytes—but in other cases, particularly when using combined antigenic vaccines, this approach is very complex. Some methods that have been attempted include the use of two vaccines, one directed at generating a blood response and the other a liver-stage response. These two vaccines could then be injected into two different sites, thus enabling the use of a more specific and potentially efficacious delivery system.

To increase, accelerate or modify the development of an immune response to a vaccine candidate it is often necessary to combine the antigenic substance to be delivered with an adjuvant or specialised delivery system. These terms are often used interchangeably in relation to vaccine development; however in most cases a distinction can be made. An adjuvant is typically thought of as a substance used in combination with the antigen to produce a more substantial and robust immune response than that elicited by the antigen alone. This is achieved through three mechanisms: by affecting the antigen delivery and presentation, by inducing the production of immunomodulatory cytokines, and by affecting the antigen presenting cells (APC). Adjuvants can consist of many different materials, from cell microparticles to other particulated delivery systems (e.g. liposomes).

Adjuvants are crucial in affecting the specificity and isotype of the necessary antibodies. They are thought to be able to potentiate the link between the innate and adaptive immune responses. Due to the diverse nature of substances that can potentially have this effect on the immune system, it is difficult to classify adjuvants into specific groups. In most circumstances they consist of easily identifiable components of micro-organisms that are recognised by the innate immune system cells. The role of delivery systems is primarily to direct the chosen adjuvant and antigen into target cells to attempt to increase the efficacy of the vaccine further, therefore acting synergistically with the adjuvant.

There is increasing concern that the use of very potent adjuvants could precipitate autoimmune responses, making it imperative that the vaccine is focused on the target cells only. Specific delivery systems can reduce this risk by limiting the potential toxicity and systemic distribution of newly developed adjuvants.

Studies into the efficacy of malaria vaccines developed to date[when?] have illustrated that the presence of an adjuvant is key in determining any protection gained against malaria. A large number of natural and synthetic adjuvants have been identified throughout the history of vaccine development. Options identified thus far for use combined with a malaria vaccine include mycobacterial cell walls, liposomes, monophosphoryl lipid A and squalene.

History

Individuals who are exposed to the parasite in endemic countries develop acquired immunity against disease and death. Such immunity does not however prevent malarial infection; immune individuals often harbour asymptomatic parasites in their blood. This does, however, imply that it is possible to create an immune response that protects against the harmful effects of the parasite.

Research shows that if immunoglobulin is taken from immune adults, purified and then given to individuals who have no protective immunity, some protection can be gained.[42]

Irradiated mosquitoes

In 1967, it was reported that a level of immunity to the Plasmodium berghei parasite could be given to mice by exposing them to sporozoites that had been irradiated by x-rays.[43] Subsequent human studies in the 1970s showed that humans could be immunized against Plasmodium vivax and Plasmodium falciparum by exposing them to the bites of significant numbers of irradiated mosquitos.[44]

From 1989 to 1999, eleven volunteers recruited from the United States Public Health ServiceUnited States Army, and United States Navy were immunized against Plasmodium falciparum by the bites of 1001–2927 mosquitoes that had been irradiated with 15,000 rads of gamma rays from a Co-60 or Cs-137 source.[45] This level of radiation is sufficient to attenuate the malaria parasites so that, while they can still enter hepatic cells, they cannot develop into schizonts nor infect red blood cells.[45] Over a span of 42 weeks, 24 of 26 tests on the volunteers showed that they were protected from malaria.[46]

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  37. ^ Mullin E (13 January 2014). “Scientists capture key protein structures that could aid malaria vaccine design”. fiercebiotechresearch.com. Retrieved 16 January 2014.
  38. ^ Batchelor JD, Malpede BM, Omattage NS, DeKoster GT, Henzler-Wildman KA, Tolia NH (January 2014). “Red blood cell invasion by Plasmodium vivax: structural basis for DBP engagement of DARC”PLOS Pathogens10 (1): e1003869. doi:10.1371/journal.ppat.1003869PMC 3887093PMID 24415938.
  39. ^ Mullin E (27 May 2014). “Antigen Discovery could advance malaria vaccine”. fiercebiotechresearch.com. Retrieved 22 June2014.
  40. ^ Raj DK, Nixon CP, Nixon CE, Dvorin JD, DiPetrillo CG, Pond-Tor S, et al. (May 2014). “Antibodies to PfSEA-1 block parasite egress from RBCs and protect against malaria infection”Science344(6186): 871–7. Bibcode:2014Sci…344..871Rdoi:10.1126/science.1254417PMC 4184151PMID 24855263.
  41. ^ Plassmeyer ML, Reiter K, Shimp RL, Kotova S, Smith PD, Hurt DE, et al. (September 2009). “Structure of the Plasmodium falciparum circumsporozoite protein, a leading malaria vaccine candidate”The Journal of Biological Chemistry284 (39): 26951–63. doi:10.1074/jbc.M109.013706PMC 2785382PMID 19633296.
  42. ^ “Immunoglobulin Therapy & Other Medical Therapies for Antibody Deficiencies”Immune Deficiency Foundation. Retrieved 30 September 2019.
  43. ^ Nussenzweig RS, Vanderberg J, Most H, Orton C (October 1967). “Protective immunity produced by the injection of x-irradiated sporozoites of plasmodium berghei”. Nature216 (5111): 160–2. Bibcode:1967Natur.216..160Ndoi:10.1038/216160a0PMID 6057225S2CID 4283134.
  44. ^ Clyde DF (May 1975). “Immunization of man against falciparum and vivax malaria by use of attenuated sporozoites”. The American Journal of Tropical Medicine and Hygiene24 (3): 397–401. doi:10.4269/ajtmh.1975.24.397PMID 808142.
  45. Jump up to:a b Hoffman SL, Goh LM, Luke TC, Schneider I, Le TP, Doolan DL, et al. (April 2002). “Protection of humans against malaria by immunization with radiation-attenuated Plasmodium falciparum sporozoites”The Journal of Infectious Diseases185 (8): 1155–64. doi:10.1086/339409PMID 11930326.
  46. ^ Hoffman SL, Goh LM, Luke TC, Schneider I, Le TP, Doolan DL, et al. (April 2002). “Protection of humans against malaria by immunization with radiation-attenuated Plasmodium falciparum sporozoites”The Journal of Infectious Diseases185 (8): 1155–64. doi:10.1086/339409PMID 11930326.

Further reading

External links

Screened cup of malaria-infected mosquitoes which will infect a volunteer in a clinical trial
Vaccine description
TargetMalaria
Vaccine typeProtein subunit
Clinical data
Trade namesMosquirix
Routes of
administration
Intramuscular[1]
ATC codeNone
Legal status
Legal statusEU: Rx-only [1]
Identifiers
CAS Number149121-47-1
ChemSpidernone

//////////////RTS,S/AS01, Mosquirix, malaria vaccine, gsk, VACCINE, RTS,S, APPROVALS 2021

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CHLOROQUINE, クロロキン;Хлорохин , クロロキン , كلوروكين


Chloroquine

Chloroquine.svg

CHLOROQUINE

N4-(7-Chloroquinolin-4-yl)-N1,N1-diethylpentane-1,4-diamine
Хлорохин [Russian] [INN]
クロロキン [Japanese]
كلوروكين [Arabic] [INN]
Formula
C18H26ClN3
CAS
54-05-7
Mol weight
319.8721
CAS Registry Number: 54-05-7
CAS Name: N4-(7-Chloro-4-quinolinyl)-N1,N1-diethyl-1,4-pentanediamine
Additional Names: 7-chloro-4-(4-diethylamino-1-methylbutylamino)quinoline
Manufacturers’ Codes: SN-7618; RP-3377
Molecular Formula: C18H26ClN3
Molecular Weight: 319.87
Percent Composition: C 67.59%, H 8.19%, Cl 11.08%, N 13.14%
Literature References: Prepd by the condensation of 4,7-dichloroquinoline with 1-diethylamino-4-aminopentane: DE 683692 (1939); H. Andersag et al., US 2233970 (1941 to Winthrop); Surrey, Hammer, J. Am. Chem. Soc. 68, 113 (1946). Review: Hahn in Antibiotics vol. 3, J. W. Corcoran, F. E. Hahn, Eds. (Springer-Verlag, New York, 1975) pp 58-78. Comprehensive description: D. D. Hong, Anal. Profiles Drug Subs. 5, 61-85 (1976). Comparative clinical trial with dapsone in rheumatoid arthritis: P. D. Fowler et al., Ann. Rheum. Dis. 43, 200 (1984); with penicillamine: T. Gibson et al., Br. J. Rheumatol. 26, 279 (1987).
Properties: mp 87°.
Melting point: mp 87°
Image result for CHLOROQUINE
Derivative Type: Diphosphate
CAS Registry Number: 50-63-5
Trademarks: Arechin (Polfa); Avloclor (AstraZeneca); Malaquin (Ahn Gook); Resochin (Bayer)
Molecular Formula: C18H26ClN3.2H3PO4
Molecular Weight: 515.86
Percent Composition: C 41.91%, H 6.25%, Cl 6.87%, N 8.15%, P 12.01%, O 24.81%
Properties: Bitter, colorless crystals. Dimorphic. One modification, mp 193-195°; the other, mp 215-218°. Freely sol in water; pH of 1% soln about 4.5; less sol at neutral and alkaline pH. Stable to heat in solns of pH 4.0 to 6.5. Practically insol in alcohol, benzene, chloroform, ether.
Melting point: mp 193-195°; mp 215-218°
Derivative Type: Sulfate
CAS Registry Number: 132-73-0
Trademarks: Aralen (Sanofi-Synthelabo); Nivaquine (Aventis)
Molecular Formula: C18H26ClN3.H2SO4
Molecular Weight: 417.95
Percent Composition: C 51.73%, H 6.75%, Cl 8.48%, N 10.05%, S 7.67%, O 15.31%
Therap-Cat: Antimalarial; antiamebic; antirheumatic. Lupus erythematosus suppressant.
Keywords: Antiamebic; Antiarthritic/Antirheumatic; Antimalarial; Lupus Erythematosus Suppressant.

Chloroquine is a medication used primarily to prevent and to treat malaria in areas where that parasitic disease is known to remain sensitive to its effects.[1] A benefit of its use in therapy, when situations allow, is that it can be taken by mouth (versus by injection).[1] Controlled studies of cases involving human pregnancy are lacking, but the drug may be safe for use for such patients.[verification needed][1][2] However, the agent is not without the possibility of serious side effects at standard doses,[1][3] and complicated cases, including infections of certain types or caused by resistant strains, typically require different or additional medication.[1] Chloroquine is also used as a medication for rheumatoid arthritislupus erythematosus, and other parasitic infections (e.g., amebiasis occurring outside of the intestines).[1] Beginning in 2020, studies have proceeded on its use as a coronavirus antiviral, in possible treatment of COVID-19.[4]

Chloroquine, otherwise known as chloroquine phosphate, is in the 4-aminoquinoline class of drugs.[1] As an antimalarial, it works against the asexual form of the malaria parasite in the stage of its life cycle within the red blood cell.[1] In its use against rheumatoid arthritis and lupus erythematosus, its activity as a mild immunosuppressive underlies its mechanism.[1] Antiviral activities, established and putative, are attributed to chloroquines inhibition of glycosylation pathways (of host receptor sialylation or virus protein post-translational modification), or to inhibition of virus endocytosis (e.g., via alkalisation of endosomes), or other possible mechanisms.[5] Common side effects resulting from these therapeutic uses, at common doses, include muscle problems,[clarification needed] loss of appetite, diarrhea, and skin rash.[clarification needed][1] Serious side effects include problems with vision (retinopathy), muscle damage, seizures, and certain anemias.[1][6]

Chloroquine was discovered in 1934 by Hans Andersag.[7][8] It is on the World Health Organization’s List of Essential Medicines, the safest and most effective medicines needed in a health system.[9] It is available as a generic medication.[1] The wholesale cost in the developing world is about US$0.04.[10] In the United States, it costs about US$5.30 per dose.[1]

Medical uses

Malaria

Distribution of malaria in the world:[11]
♦ Elevated occurrence of chloroquine- or multi-resistant malaria
♦ Occurrence of chloroquine-resistant malaria
♦ No Plasmodium falciparum or chloroquine-resistance
♦ No malaria

Chloroquine has been used in the treatment and prevention of malaria from Plasmodium vivaxP. ovale, and P. malariae. It is generally not used for Plasmodium falciparum as there is widespread resistance to it.[12][13]

Chloroquine has been extensively used in mass drug administrations, which may have contributed to the emergence and spread of resistance. It is recommended to check if chloroquine is still effective in the region prior to using it.[14] In areas where resistance is present, other antimalarials, such as mefloquine or atovaquone, may be used instead. The Centers for Disease Control and Prevention recommend against treatment of malaria with chloroquine alone due to more effective combinations.[15]

Amebiasis

In treatment of amoebic liver abscess, chloroquine may be used instead of or in addition to other medications in the event of failure of improvement with metronidazole or another nitroimidazole within 5 days or intolerance to metronidazole or a nitroimidazole.[16]

Rheumatic disease

As it mildly suppresses the immune system, chloroquine is used in some autoimmune disorders, such as rheumatoid arthritis and lupus erythematosus.[1]

Side effects

Side effects include blurred vision, nausea, vomiting, abdominal cramps, headache, diarrhea, swelling legs/ankles, shortness of breath, pale lips/nails/skin, muscle weakness, easy bruising/bleeding, hearing and mental problems.[17][18]

  • Unwanted/uncontrolled movements (including tongue and face twitching) [17]
  • Deafness or tinnitus.[17]
  • Nausea, vomiting, diarrhea, abdominal cramps[18]
  • Headache.[17]
  • Mental/mood changes (such as confusion, personality changes, unusual thoughts/behavior, depression, feeling being watched, hallucinating)[17][18]
  • Signs of serious infection (such as high fever, severe chills, persistent sore throat)[17]
  • Skin itchiness, skin color changes, hair loss, and skin rashes.[18][19]
    • Chloroquine-induced itching is very common among black Africans (70%), but much less common in other races. It increases with age, and is so severe as to stop compliance with drug therapy. It is increased during malaria fever; its severity is correlated to the malaria parasite load in blood. Some evidence indicates it has a genetic basis and is related to chloroquine action with opiate receptors centrally or peripherally.[20]
  • Unpleasant metallic taste
    • This could be avoided by “taste-masked and controlled release” formulations such as multiple emulsions.[21]
  • Chloroquine retinopathy
  • Electrocardiographic changes[22]
    • This manifests itself as either conduction disturbances (bundle-branch block, atrioventricular block) or Cardiomyopathy – often with hypertrophy, restrictive physiology, and congestive heart failure. The changes may be irreversible. Only two cases have been reported requiring heart transplantation, suggesting this particular risk is very low. Electron microscopy of cardiac biopsies show pathognomonic cytoplasmic inclusion bodies.
  • Pancytopeniaaplastic anemia, reversible agranulocytosislow blood plateletsneutropenia.[23]

Pregnancy

Chloroquine has not been shown to have any harmful effects on the fetus when used for malarial prophylaxis.[24] Small amounts of chloroquine are excreted in the breast milk of lactating women. However, this drug can be safely prescribed to infants, the effects are not harmful. Studies with mice show that radioactively tagged chloroquine passed through the placenta rapidly and accumulated in the fetal eyes which remained present five months after the drug was cleared from the rest of the body.[23][25] Women who are pregnant or planning on getting pregnant are still advised against traveling to malaria-risk regions.[24]

Elderly

There is not enough evidence to determine whether chloroquine is safe to be given to people aged 65 and older. Since it is cleared by the kidneys, toxicity should be monitored carefully in people with poor kidney functions.[23]

Drug interactions

Chloroquine has a number of drug-drug interactions that might be of clinical concern:[citation needed]

Overdose

Chloroquine is very dangerous in overdose. It is rapidly absorbed from the gut. In 1961, a published compilation of case reports contained accounts of three children who took overdoses and died within 2.5 hours of taking the drug. While the amount of the overdose was not stated, the therapeutic index for chloroquine is known to be small.[26] One of the children died after taking 0.75 or 1 gram, or twice a single therapeutic amount for children. Symptoms of overdose include headache, drowsiness, visual disturbances, nausea and vomiting, cardiovascular collapse, seizures, and sudden respiratory and cardiac arrest.[23]

An analog of chloroquine – hydroxychloroquine – has a long half-life (32–56 days) in blood and a large volume of distribution (580–815 L/kg).[27] The therapeutic, toxic and lethal ranges are usually considered to be 0.03 to 15 mg/l, 3.0 to 26 mg/l and 20 to 104 mg/l, respectively. However, nontoxic cases have been reported up to 39 mg/l, suggesting individual tolerance to this agent may be more variable than previously recognised.[27]

Pharmacology

Chloroquine’s absorption of the drug is rapid. It is widely distributed in body tissues. It’s protein binding is 55%.[ It’s metabolism is partially hepatic, giving rise to its main metabolite, desethylchloroquine. It’s excretion os ≥50% as unchanged drug in urine, where acidification of urine increases its elimination It has a very high volume of distribution, as it diffuses into the body’s adipose tissue.

Accumulation of the drug may result in deposits that can lead to blurred vision and blindness. It and related quinines have been associated with cases of retinal toxicity, particularly when provided at higher doses for longer times. With long-term doses, routine visits to an ophthalmologist are recommended.

Chloroquine is also a lysosomotropic agent, meaning it accumulates preferentially in the lysosomes of cells in the body. The pKa for the quinoline nitrogen of chloroquine is 8.5, meaning—in simplified terms, considering only this basic site—it is about 10% deprotonated at physiological pH (per the Henderson-Hasselbalch equation) This decreases to about 0.2% at a lysosomal pH of 4.6.Because the deprotonated form is more membrane-permeable than the protonated form, a quantitative “trapping” of the compound in lysosomes results.

Mechanism of action

Medical quinolines

Malaria

Hemozoin formation in P. falciparum: many antimalarials are strong inhibitors of hemozoin crystal growth.

The lysosomotropic character of chloroquine is believed to account for much of its antimalarial activity; the drug concentrates in the acidic food vacuole of the parasite and interferes with essential processes. Its lysosomotropic properties further allow for its use for in vitro experiments pertaining to intracellular lipid related diseases,[28][29] autophagy, and apoptosis.[30]

Inside red blood cells, the malarial parasite, which is then in its asexual lifecycle stage, must degrade hemoglobin to acquire essential amino acids, which the parasite requires to construct its own protein and for energy metabolism. Digestion is carried out in a vacuole of the parasitic cell.[citation needed]

Hemoglobin is composed of a protein unit (digested by the parasite) and a heme unit (not used by the parasite). During this process, the parasite releases the toxic and soluble molecule heme. The heme moiety consists of a porphyrin ring called Fe(II)-protoporphyrin IX (FP). To avoid destruction by this molecule, the parasite biocrystallizes heme to form hemozoin, a nontoxic molecule. Hemozoin collects in the digestive vacuole as insoluble crystals.[citation needed]

Chloroquine enters the red blood cell by simple diffusion, inhibiting the parasite cell and digestive vacuole. Chloroquine then becomes protonated (to CQ2+), as the digestive vacuole is known to be acidic (pH 4.7); chloroquine then cannot leave by diffusion. Chloroquine caps hemozoin molecules to prevent further biocrystallization of heme, thus leading to heme buildup. Chloroquine binds to heme (or FP) to form the FP-chloroquine complex; this complex is highly toxic to the cell and disrupts membrane function. Action of the toxic FP-chloroquine and FP results in cell lysis and ultimately parasite cell autodigestion. [31] Parasites that do not form hemozoin are therefore resistant to chloroquine.[32]

Resistance in malaria[edit source]

Since the first documentation of P. falciparum chloroquine resistance in the 1950s, resistant strains have appeared throughout East and West Africa, Southeast Asia, and South America. The effectiveness of chloroquine against P. falciparum has declined as resistant strains of the parasite evolved. They effectively neutralize the drug via a mechanism that drains chloroquine away from the digestive vacuole. Chloroquine-resistant cells efflux chloroquine at 40 times the rate of chloroquine-sensitive cells; the related mutations trace back to transmembrane proteins of the digestive vacuole, including sets of critical mutations in the P. falciparum chloroquine resistance transporter (PfCRT) gene. The mutated protein, but not the wild-type transporter, transports chloroquine when expressed in Xenopus oocytes (frog’s eggs) and is thought to mediate chloroquine leak from its site of action in the digestive vacuole.[33] Resistant parasites also frequently have mutated products of the ABC transporter P. falciparum multidrug resistance (PfMDR1) gene, although these mutations are thought to be of secondary importance compared to PfcrtVerapamil, a Ca2+ channel blocker, has been found to restore both the chloroquine concentration ability and sensitivity to this drug. Recently, an altered chloroquine-transporter protein CG2 of the parasite has been related to chloroquine resistance, but other mechanisms of resistance also appear to be involved.[34] Research on the mechanism of chloroquine and how the parasite has acquired chloroquine resistance is still ongoing, as other mechanisms of resistance are likely.[citation needed]

Other agents which have been shown to reverse chloroquine resistance in malaria are chlorpheniraminegefitinibimatinibtariquidar and zosuquidar.[35]

Antiviral

Chloroquine has antiviral effects.[36] It increases late endosomal or lysosomal pH, resulting in impaired release of the virus from the endosome or lysosome – release requires a low pH. The virus is therefore unable to release its genetic material into the cell and replicate.[37][38]

Chloroquine also seems to act as a zinc ionophore, that allows extracellular zinc to enter the cell and inhibit viral RNA-dependent RNA polymerase.[39][40]

Other

Chloroquine inhibits thiamine uptake.[41] It acts specifically on the transporter SLC19A3.

Against rheumatoid arthritis, it operates by inhibiting lymphocyte proliferation, phospholipase A2, antigen presentation in dendritic cells, release of enzymes from lysosomes, release of reactive oxygen species from macrophages, and production of IL-1.

History

In Peru the indigenous people extracted the bark of the Cinchona plant[42] trees and used the extract (Chinchona officinalis) to fight chills and fever in the seventeenth century. In 1633 this herbal medicine was introduced in Europe, where it was given the same use and also began to be used against malaria.[43] The quinoline antimalarial drug quinine was isolated from the extract in 1820, and chloroquine is an analogue of this.

Chloroquine was discovered in 1934, by Hans Andersag and coworkers at the Bayer laboratories, who named it “Resochin”.[44] It was ignored for a decade, because it was considered too toxic for human use. During World War II, United States government-sponsored clinical trials for antimalarial drug development showed unequivocally that chloroquine has a significant therapeutic value as an antimalarial drug. It was introduced into clinical practice in 1947 for the prophylactic treatment of malaria.[45]

Society and culture

Resochin tablet package

Formulations

Chloroquine comes in tablet form as the phosphate, sulfate, and hydrochloride salts. Chloroquine is usually dispensed as the phosphate.[46]

Names

Brand names include Chloroquine FNA, Resochin, Dawaquin, and Lariago.[47]

Other animals

Chloroquine is used to control the aquarium fish parasite Amyloodinium ocellatum.[48]

Research

COVID-19

In late January 2020 during the 2019–20 coronavirus outbreak, Chinese medical researchers stated that exploratory research into chloroquine and two other medications, remdesivir and lopinavir/ritonavir, seemed to have “fairly good inhibitory effects” on the SARS-CoV-2 virus, which is the virus that causes COVID-19. Requests to start clinical testing were submitted.[49] Chloroquine had been also proposed as a treatment for SARS, with in vitro tests inhibiting the SARS-CoV virus.[50][51]

Chloroquine has been recommended by Chinese, South Korean and Italian health authorities for the treatment of COVID-19.[52][53] These agencies noted contraindications for people with heart disease or diabetes.[54] Both chloroquine and hydroxychloroquine were shown to inhibit SARS-CoV-2 in vitro, but a further study concluded that hydroxychloroquine was more potent than chloroquine, with a more tolerable safety profile.[55] Preliminary results from a trial suggested that chloroquine is effective and safe in COVID-19 pneumonia, “improving lung imaging findings, promoting a virus-negative conversion, and shortening the disease course.”[56] Self-medication with chloroquine has caused one known fatality.[57]

On 24 March 2020, NBC News reported[58] a fatality due to misuse of a chloroquine product used to control fish parasites.[59]

Other viruses

In October 2004, a group of researchers at the Rega Institute for Medical Research published a report on chloroquine, stating that chloroquine acts as an effective inhibitor of the replication of the severe acute respiratory syndrome coronavirus (SARS-CoV) in vitro.[60]

Chloroquine was being considered in 2003, in pre-clinical models as a potential agent against chikungunya fever.[61]

Other

The radiosensitizing and chemosensitizing properties of chloroquine are beginning to be exploited in anticancer strategies in humans.[62][63] In biomedicinal science, chloroquine is used for in vitro experiments to inhibit lysosomal degradation of protein products.

 

 

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References

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  33. ^ Martin RE, Marchetti RV, Cowan AI, Howitt SM, Bröer S, Kirk K (September 2009). “Chloroquine transport via the malaria parasite’s chloroquine resistance transporter”. Science325 (5948): 1680–2. Bibcode:2009Sci…325.1680Mdoi:10.1126/science.1175667PMID 19779197.
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  35. ^ Alcantara LM, Kim J, Moraes CB, Franco CH, Franzoi KD, Lee S, et al. (June 2013). “Chemosensitization potential of P-glycoprotein inhibitors in malaria parasites”. Experimental Parasitology134 (2): 235–43. doi:10.1016/j.exppara.2013.03.022PMID 23541983.
  36. ^ Savarino A, Boelaert JR, Cassone A, Majori G, Cauda R (November 2003). “Effects of chloroquine on viral infections: an old drug against today’s diseases?”. The Lancet. Infectious Diseases3(11): 722–7. doi:10.1016/s1473-3099(03)00806-5PMID 14592603.
  37. ^ Al-Bari MA (February 2017). “Targeting endosomal acidification by chloroquine analogs as a promising strategy for the treatment of emerging viral diseases”Pharmacology Research & Perspectives5 (1): e00293. doi:10.1002/prp2.293PMC 5461643PMID 28596841.
  38. ^ Fredericksen BL, Wei BL, Yao J, Luo T, Garcia JV (November 2002). “Inhibition of endosomal/lysosomal degradation increases the infectivity of human immunodeficiency virus”Journal of Virology76 (22): 11440–6. doi:10.1128/JVI.76.22.11440-11446.2002PMC 136743PMID 12388705.
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  40. ^ te Velthuis AJ, van den Worm SH, Sims AC, Baric RS, Snijder EJ, van Hemert MJ (November 2010). “Zn(2+) inhibits coronavirus and arterivirus RNA polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture”PLoS Pathogens6 (11): e1001176. doi:10.1371/journal.ppat.1001176PMC 2973827PMID 21079686.
  41. ^ Huang Z, Srinivasan S, Zhang J, Chen K, Li Y, Li W, et al. (2012). “Discovering thiamine transporters as targets of chloroquine using a novel functional genomics strategy”PLOS Genetics8 (11): e1003083. doi:10.1371/journal.pgen.1003083PMC 3510038PMID 23209439.
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  44. ^ Krafts K, Hempelmann E, Skórska-Stania A (July 2012). “From methylene blue to chloroquine: a brief review of the development of an antimalarial therapy”. Parasitology Research111 (1): 1–6. doi:10.1007/s00436-012-2886-xPMID 22411634.
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  49. ^ “Could an old malaria drug help fight the new coronavirus?”asbmb.orgArchived from the original on 6 February 2020. Retrieved 6 February 2020.
  50. ^ Keyaerts E, Vijgen L, Maes P, Neyts J, Van Ranst M (October 2004). “In vitro inhibition of severe acute respiratory syndrome coronavirus by chloroquine”. Biochemical and Biophysical Research Communications323 (1): 264–8. doi:10.1016/j.bbrc.2004.08.085PMID 15351731.
  51. ^ Devaux CA, Rolain JM, Colson P, Raoult D. New insights on the antiviral effects of chloroquine against coronavirus: what to expect for COVID-19? Int J Antimicrob Agents. 2020 Mar 11:105938. doi:10.1016/j.ijantimicag.2020.105938 PMID 32171740
  52. ^ “Physicians work out treatment guidelines for coronavirus”m.koreabiomed.com (in Korean). 13 February 2020. Archivedfrom the original on 17 March 2020. Retrieved 18 March 2020.
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  54. ^ “Plaquenil (hydroxychloroquine sulfate) dose, indications, adverse effects, interactions… from PDR.net”http://www.pdr.netArchivedfrom the original on 18 March 2020. Retrieved 19 March 2020.
  55. ^ Yao X, Ye F, Zhang M, Cui C, Huang B, Niu P, et al. (March 2020). “In Vitro Antiviral Activity and Projection of Optimized Dosing Design of Hydroxychloroquine for the Treatment of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)”. Clinical Infectious Diseasesdoi:10.1093/cid/ciaa237PMID 32150618.
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  57. ^ Edwards, Erika; Hillyard, Vaughn (23 March 2020). “Man dies after ingesting chloroquine in an attempt to prevent coronavirus”NBC News. Retrieved 24 March 2020.
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  60. ^ Keyaerts E, Vijgen L, Maes P, Neyts J, Van Ranst M (October 2004). “In vitro inhibition of severe acute respiratory syndrome coronavirus by chloroquine”. Biochemical and Biophysical Research Communications323 (1): 264–8. doi:10.1016/j.bbrc.2004.08.085PMID 15351731.
  61. ^ Savarino A, Boelaert JR, Cassone A, Majori G, Cauda R (November 2003). “Effects of chloroquine on viral infections: an old drug against today’s diseases?”. The Lancet. Infectious Diseases3(11): 722–7. doi:10.1016/S1473-3099(03)00806-5PMID 14592603.
  62. ^ Savarino A, Lucia MB, Giordano F, Cauda R (October 2006). “Risks and benefits of chloroquine use in anticancer strategies”. The Lancet. Oncology7 (10): 792–3. doi:10.1016/S1470-2045(06)70875-0PMID 17012039.
  63. ^ Sotelo J, Briceño E, López-González MA (March 2006). “Adding chloroquine to conventional treatment for glioblastoma multiforme: a randomized, double-blind, placebo-controlled trial”. Annals of Internal Medicine144 (5): 337–43. doi:10.7326/0003-4819-144-5-200603070-00008PMID 16520474.
    “Summaries for patients. Adding chloroquine to conventional chemotherapy and radiotherapy for glioblastoma multiforme”. Annals of Internal Medicine144 (5): I31. March 2006. doi:10.7326/0003-4819-144-5-200603070-00004PMID 16520470.

External links

“Chloroquine”Drug Information Portal. U.S. National Library of Medicine.

Chloroquine
Chloroquine.svg
Chloroquine 3D structure.png
Clinical data
Pronunciation /ˈklɔːrəkwɪn/
Trade names Aralen, other
Other names Chloroquine phosphate
AHFS/Drugs.com Monograph
License data
ATC code
Legal status
Legal status
Pharmacokinetic data
Metabolism Liver
Elimination half-life 1-2 months
Identifiers
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
NIAID ChemDB
CompTox Dashboard (EPA)
ECHA InfoCard 100.000.175 Edit this at Wikidata
Chemical and physical data
Formula C18H26ClN3
Molar mass 319.872 g·mol−1
3D model (JSmol)

//////////////CHLOROQUINE,, クロロキン, ANTIMALARIAL, COVID 19, CORONA VIRUS, Хлорохинクロロキン كلوروكين

Hydroxychloroquine, ヒドロキシクロロキン, гидроксихлорохин , هيدروكسيكلوروكين , 羟氯喹 ,


ChemSpider 2D Image | hydroxychloroquine | C18H26ClN3O

 

Hydroxychloroquine
ヒドロキシクロロキン;
Formula
C18H26ClN3O
cas
118-42-3
sulphate 747-36-4
Mol weight
335.8715

 

гидроксихлорохин [Russian] [INN]
هيدروكسيكلوروكين [Arabic] [INN]
羟氯喹 [Chinese] [INN]
Oxychlorochin, Plaquenil Plaquenil®, 

Hydroxychloroquine (HCQ), sold under the brand name Plaquenil among others, is a medication used for the prevention and treatment of certain types of malaria.[2] Specifically it is used for chloroquine-sensitive malaria.[3] Other uses include treatment of rheumatoid arthritislupus, and porphyria cutanea tarda.[2] It is taken by mouth.[2] It is also being used as an experimental treatment for coronavirus disease 2019 (COVID-19).[4]

Common side effects include vomitingheadache, changes in vision and muscle weakness.[2] Severe side effects may include allergic reactions.[2] Although all risk cannot be excluded it remains a treatment for rheumatic disease during pregnancy.[5] Hydroxychloroquine is in the antimalarial and 4-aminoquinoline families of medication.[2]

Hydroxychloroquine was approved for medical use in the United States in 1955.[2] It is on the World Health Organization’s List of Essential Medicines, the safest and most effective medicines needed in a health system.[6] The wholesale cost in the developing world is about US$4.65 per month as of 2015, when used for rheumatoid arthritis or lupus.[7] In the United States the wholesale cost of a month of treatment is about US$25 as of 2020.[8] In the United Kingdom this dose costs the NHS about £ 5.15.[9] In 2017, it was the 128th most prescribed medication in the United States with more than five million prescriptions.[10]

Medical use

Hydroxychloroquine treats malaria, systemic lupus erythematosus, rheumatic disorders like rheumatoid arthritisporphyria cutanea tarda, and Q fever.[2]

In 2014, its efficacy to treat Sjögren syndrome was questioned in a double-blind study involving 120 patients over a 48-week period.[11]

Hydroxychloroquine is widely used in the treatment of post-Lyme arthritis. It may have both an anti-spirochaete activity and an anti-inflammatory activity, similar to the treatment of rheumatoid arthritis.[12]

Contraindications

The drug label advises that hydroxychloroquine should not be prescribed to individuals with known hypersensitivity to 4-Aminoquinoline compounds.[13] There are a range of other contraindications[14] [15] and caution is required if patients have certain heart conditions, diabetes, psoriasis etc.

Side effects[

The most common adverse effects are a mild nausea and occasional stomach cramps with mild diarrhea. The most serious adverse effects affect the eye, with dose-related retinopathy as a concern even after hydroxychloroquine use is discontinued.[2] For short-term treatment of acute malaria, adverse effects can include abdominal cramps, diarrhea, heart problems, reduced appetite, headache, nausea and vomiting.[2]

For prolonged treatment of lupus or rheumatoid arthritis, adverse effects include the acute symptoms, plus altered eye pigmentation, acneanemia, bleaching of hair, blisters in mouth and eyes, blood disorders, convulsions, vision difficulties, diminished reflexes, emotional changes, excessive coloring of the skin, hearing loss, hives, itching, liver problems or liver failureloss of hair, muscle paralysis, weakness or atrophy, nightmares, psoriasis, reading difficulties, tinnitus, skin inflammation and scaling, skin rash, vertigoweight loss, and occasionally urinary incontinence.[2] Hydroxychloroquine can worsen existing cases of both psoriasis and porphyria.[2]

Children may be especially vulnerable to developing adverse effects from hydroxychloroquine.[2]

Eyes

One of the most serious side effects is retinopathy (generally with chronic use).[2][16] People taking 400 mg of hydroxychloroquine or less per day generally have a negligible risk of macular toxicity, whereas the risk begins to go up when a person takes the medication over 5 years or has a cumulative dose of more than 1000 grams. The daily safe maximum dose for eye toxicity can be computed from one’s height and weight using this calculator. Cumulative doses can also be calculated from this calculator. Macular toxicity is related to the total cumulative dose rather than the daily dose. Regular eye screening, even in the absence of visual symptoms, is recommended to begin when either of these risk factors occurs.[17]

Toxicity from hydroxychloroquine may be seen in two distinct areas of the eye: the cornea and the macula. The cornea may become affected (relatively commonly) by an innocuous cornea verticillata or vortex keratopathy and is characterized by whorl-like corneal epithelial deposits. These changes bear no relationship to dosage and are usually reversible on cessation of hydroxychloroquine.

The macular changes are potentially serious. Advanced retinopathy is characterized by reduction of visual acuity and a “bull’s eye” macular lesion which is absent in early involvement.

Overdose

Due to rapid absorption, symptoms of overdose can occur within a half an hour after ingestion. Overdose symptoms include convulsions, drowsiness, headache, heart problems or heart failure, difficulty breathing and vision problems.

Hydroxychloroquine overdoses are rarely reported, with 7 previous cases found in the English medical literature. In one such case, a 16-year-old girl who had ingested a handful of hydroxychloroquine 200mg presented with tachycardia (heart rate 110 beats/min), hypotension (systolic blood pressure 63 mm Hg), central nervous system depression, conduction defects (ORS = 0.14 msec), and hypokalemia (K = 2.1 meq/L). Treatment consisted of fluid boluses and dopamine, oxygen, and potassium supplementation. The presence of hydroxychloroquine was confirmed through toxicologic tests. The patient’s hypotension resolved within 4.5 hours, serum potassium stabilized in 24 hours, and tachycardia gradually decreased over 3 days.[18]

Interactions

The drug transfers into breast milk and should be used with care by pregnant or nursing mothers.[citation needed]

Care should be taken if combined with medication altering liver function as well as aurothioglucose (Solganal), cimetidine (Tagamet) or digoxin (Lanoxin). HCQ can increase plasma concentrations of penicillamine which may contribute to the development of severe side effects. It enhances hypoglycemic effects of insulin and oral hypoglycemic agents. Dose altering is recommended to prevent profound hypoglycemiaAntacids may decrease the absorption of HCQ. Both neostigmine and pyridostigmine antagonize the action of hydroxychloroquine.[19]

While there may be a link between hydroxychloroquine and hemolytic anemia in those with glucose-6-phosphate dehydrogenase deficiency, this risk may be low in those of African descent.[20]

Specifically, the FDA drug label for hydroxychloroquine lists the following drug interactions [13]:

  • Digoxin (wherein it may result in increased serum digoxin levels)
  • Insulin or antidiabetic drugs (wherein it may enhance the effects of a hypoglycemic treatment)
  • Drugs that prolong QT interval and other arrhythmogenic drugs (as Hydroxychloroquine prolongs the QT interval and may increase the risk of inducing ventricular arrhythmias if used concurrently)
  • Mefloquine and other drugs known to lower the convulsive threshold (co-administration with other antimalarials known to lower the convulsion threshold may increase risk of convulsions)
  • Antiepileptics (concurrent use may impair the antiepileptic activity)
  • Methotrexate (combined use is unstudied and may increase the frequency of side effects)
  • Cyclosporin (wherein an increased plasma cylcosporin level was reported when used together).

Pharmacology[

Pharmacokinetics

Hydroxychloroquine has similar pharmacokinetics to chloroquine, with rapid gastrointestinal absorption and elimination by the kidneys. Cytochrome P450 enzymes (CYP2D62C83A4 and 3A5) metabolize hydroxychloroquine to N-desethylhydroxychloroquine.[21]

Pharmacodynamics

Antimalarials are lipophilic weak bases and easily pass plasma membranes. The free base form accumulates in lysosomes (acidic cytoplasmic vesicles) and is then protonated,[22] resulting in concentrations within lysosomes up to 1000 times higher than in culture media. This increases the pH of the lysosome from 4 to 6.[23] Alteration in pH causes inhibition of lysosomal acidic proteases causing a diminished proteolysis effect.[24] Higher pH within lysosomes causes decreased intracellular processing, glycosylation and secretion of proteins with many immunologic and nonimmunologic consequences.[25] These effects are believed to be the cause of a decreased immune cell functioning such as chemotaxisphagocytosis and superoxide production by neutrophils.[26] HCQ is a weak diprotic base that can pass through the lipid cell membrane and preferentially concentrate in acidic cytoplasmic vesicles. The higher pH of these vesicles in macrophages or other antigen-presenting cells limits the association of autoantigenic (any) peptides with class II MHC molecules in the compartment for peptide loading and/or the subsequent processing and transport of the peptide-MHC complex to the cell membrane.[27]

Mechanism of action

Hydroxychloroquine increases[28] lysosomal pH in antigen-presenting cells. In inflammatory conditions, it blocks toll-like receptors on plasmacytoid dendritic cells (PDCs).[citation needed] Hydroxychloroquine, by decreasing TLR signaling, reduces the activation of dendritic cells and the inflammatory process. Toll-like receptor 9 (TLR 9) recognizes DNA-containing immune complexes and leads to the production of interferon and causes the dendritic cells to mature and present antigen to T cells, therefore reducing anti-DNA auto-inflammatory process.

In 2003, a novel mechanism was described wherein hydroxychloroquine inhibits stimulation of the toll-like receptor (TLR) 9 family receptors. TLRs are cellular receptors for microbial products that induce inflammatory responses through activation of the innate immune system.[29]

As with other quinoline antimalarial drugs, the mechanism of action of quinine has not been fully resolved. The most accepted model is based on hydrochloroquinine and involves the inhibition of hemozoin biocrystallization, which facilitates the aggregation of cytotoxic heme. Free cytotoxic heme accumulates in the parasites, causing their deaths.[citation needed]

Brand names

It is frequently sold as a sulfate salt known as hydroxychloroquine sulfate.[2] 200 mg of the sulfate salt is equal to 155 mg of the base.[2]

Brand names of hydroxychloroquine include Plaquenil, Hydroquin, Axemal (in India), Dolquine, Quensyl, Quinoric.[30]

Research

COVID-19

Hydroxychloroquine and chloroquine have been recommended by Chinese and South Korean health authorities for the experimental treatment of COVID-19.[31][32] In vitro studies in cell cultures demonstrated that hydroxychloroquine was more potent than chloroquine against SARS-CoV-2.[33]

On 17 March 2020, the AIFA Scientific Technical Commission of the Italian Medicines Agency expressed a favorable opinion on including the off-label use of chloroquine and hydroxychloroquine for the treatment of SARS-CoV-2 infection.[34]

 

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Image result for hydroxychloroquine

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https://d-nb.info/1166863441/34

white solid (0.263 g, 78%). 1H NMR
(600 MHz, CDCl3
) δ 8.48 (d, J = 5.4 Hz, 1H), 7.93 (d, J = 5.4 Hz, 1H), 7.70 (d, J = 9.2 Hz, 1H), 7.34 (dd, J = 8.8, 7.3 Hz, 1H), 6.39 (d, J = 5.4 Hz, 1H), 4.96 (d, J = 7.5 Hz, 1H), 3.70 (sx,J = 6.8 Hz, 1H), 3.55 (m, 2H), 2.57 (m, 5H), 2.49 (m, 2H),
1.74–1.62 (m, 1H), 1.65–1.53 (m, 3H), 1.31 (d, J = 6.9 Hz, 3H),
1.24 (d, J = 7.2 Hz, 2H);

13C NMR (125 MHz, CDCl3) δ 152.2,
149.5, 149.2, 135.0, 129.0, 125.4, 121.2, 117.4, 99.4, 58.6, 54.9,
53.18, 48.5, 47.9, 34.5, 24.1, 20.6, 11.9. Spectra were obtained
in accordance with those previously reported [38,39].

38. Cornish, C. A.; Warren, S. J. Chem. Soc., Perkin Trans. 1 1985,
2585–2598. doi:10.1039/P19850002585
39. Münstedt, R.; Wannagat, U.; Wrobel, D. J. Organomet. Chem. 1984,
264, 135–148. doi:10.1016/0022-328X(84)85139-6

 

 

References

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  18. ^ Marquardt, Kathy; Albertson, Timothy E. (1 September 2001). “Treatment of hydroxychloroquine overdose”The American Journal of Emergency Medicine19 (5): 420–424. doi:10.1053/ajem.2001.25774ISSN 0735-6757PMID 11555803.
  19. ^ “Russian Register of Medicines: Plaquenil (hydroxychloroquine) Film-coated Tablets for Oral Use. Prescribing Information” (in Russian). Sanofi-Synthelabo. Archived from the original on 16 August 2016. Retrieved 14 July 2016.
  20. ^ Mohammad, Samya; Clowse, Megan E. B.; Eudy, Amanda M.; Criscione-Schreiber, Lisa G. (March 2018). “Examination of Hydroxychloroquine Use and Hemolytic Anemia in G6PDH-Deficient Patients”. Arthritis Care & Research70 (3): 481–485. doi:10.1002/acr.23296ISSN 2151-4658PMID 28556555.
  21. ^ Kalia, S; Dutz, JP (2007). “New Concepts in Antimalarial Use and Mode of Action in Dermatology”. Dermatologic Therapy20 (4): 160–74. doi:10.1111/j.1529-8019.2007.00131.xPMID 17970883.
  22. ^ Kaufmann, AM; Krise, JP (2007). “Lysosomal Sequestration of Amine-containing Drugs: Analysis and Therapeutic Implications”. Journal of Pharmaceutical Sciences96 (4): 729–46. doi:10.1002/jps.20792PMID 17117426.
  23. ^ Ohkuma, S; Poole, B (1978). “Fluorescence Probe Measurement of the Intralysosomal pH in Living Cells and the Perturbation of pH by Various Agents”Proceedings of the National Academy of Sciences of the United States of America75 (7): 3327–31. doi:10.1073/pnas.75.7.3327PMC 392768PMID 28524.
  24. ^ Ohkuma, S; Chudzik, J; Poole, B (1986). “The Effects of Basic Substances and Acidic Ionophores on the Digestion of Exogenous and Endogenous Proteins in Mouse Peritoneal Macrophages”The Journal of Cell Biology102 (3): 959–66. doi:10.1083/jcb.102.3.959PMC 2114118PMID 3949884.
  25. ^ Oda, K; Koriyama, Y; Yamada, E; Ikehara, Y (1986). “Effects of Weakly Basic Amines on Proteolytic Processing and Terminal Glycosylation of Secretory Proteins in Cultured Rat Hepatocytes”The Biochemical Journal240 (3): 739–45. doi:10.1042/bj2400739PMC 1147481PMID 3493770.
  26. ^ Hurst, NP; French, JK; Gorjatschko, L; Betts, WH (1988). “Chloroquine and Hydroxychloroquine Inhibit Multiple Sites in Metabolic Pathways Leading to Neutrophil Superoxide Release”. The Journal of Rheumatology15 (1): 23–27. PMID 2832600.
  27. ^ Fox, R (1996). “Anti-malarial Drugs: Possible Mechanisms of Action in Autoimmune Disease and Prospects for Drug Development”. Lupus5: S4–10. doi:10.1177/096120339600500103PMID 8803903.
  28. ^ Waller; et al. Medical Pharmacology and Therapeutics (2nd ed.). p. 370.
  29. ^ Takeda, K; Kaisho, T; Akira, S (2003). “Toll-Like Receptors”. Annual Review of Immunology21: 335–76. doi:10.1146/annurev.immunol.21.120601.141126PMID 12524386.
  30. ^ “Hydroxychloroquine trade names”Drugs-About.com. Retrieved 18 June 2019.
  31. ^ “Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia”China Law Translate. 3 March 2020. Retrieved 18 March 2020.
  32. ^ “Physicians work out treatment guidelines for coronavirus”Korea Biomedical Review. 13 February 2020. Retrieved 18 March2020.
  33. ^ Yao, Xueting; Ye, Fei; Zhang, Miao; Cui, Cheng; Huang, Baoying; Niu, Peihua; Liu, Xu; Zhao, Li; Dong, Erdan; Song, Chunli; Zhan, Siyan (9 March 2020). “In Vitro Antiviral Activity and Projection of Optimized Dosing Design of Hydroxychloroquine for the Treatment of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)”. Clinical Infectious Diseasesdoi:10.1093/cid/ciaa237ISSN 1537-6591PMID 32150618.
  34. ^ “Azioni intraprese per favorire la ricerca e l’accesso ai nuovi farmaci per il trattamento del COVID-19”Italian Medicines Agency (AIFA) (in Italian). 17 March 2020. Retrieved 18 March2020.

External links

 

Hydroxychloroquine
Hydroxychloroquine.svg
Hydroxychloroquine.png

Hydroxychloroquine freebase molecule
Clinical data
Trade names Plaquenil, others
Other names Hydroxychloroquine sulfate
AHFS/Drugs.com Monograph
MedlinePlus a601240
License data
Pregnancy
category
  • AU: D [1]
  • US: N (Not classified yet) [1]
Routes of
administration
By mouth (tablets)
ATC code
Legal status
Legal status
  • AU: S4 (Prescription only)
  • UK: POM (Prescription only)
  • US: ℞-only
  • In general: ℞ (Prescription only)
Pharmacokinetic data
Bioavailability Variable (74% on average); Tmax = 2–4.5 hours
Protein binding 45%
Metabolism Liver
Elimination half-life 32–50 days
Excretion Mostly Kidney (23–25% as unchanged drug), also biliary (<10%)
Identifiers
CAS Number
PubChem CID
IUPHAR/BPS
DrugBank
ChemSpider
UNII
KEGG
ChEBI
ChEMBL
CompTox Dashboard (EPA)
ECHA InfoCard 100.003.864 Edit this at Wikidata
Chemical and physical data
Formula C18H26ClN3O
Molar mass 335.872 g/mol g·mol−1
3D model (JSmol)

 

///////////Hydroxychloroquine, Hydroxy chloroquine, HCQ, ヒドロキシクロロキン , covid 19, coronavirus, antimalarial, гидроксихлорохинهيدروكسيكلوروكين羟氯喹Oxychlorochin, Plaquenil Plaquenil®, 

Commercial Production of Semi-Synthetic Artemisinin


STR1

Figure 1. Production of artemisinic acid or β-farnesene by engineered yeast. The sesquiterpene alkenes β-farnesene and amorphadiene are both derived from FPP (farnesyl diphosphate) by the action of specific enzymes introduced from plants: amorphadiene synthase (ADS) generates amorphadiene and β-farnesene synthase (FS) generates β-farnesene. Production strains express either ADS or FS, not both. Oxidation of amorphadiene to artemisinic acid is accomplished by the action of five plant enzymes expressed in the engineered yeast.17 Conversion of purified artemisinic acid to artemisinin is accomplished by in vitro organic chemistry. Isoprenoid production strains make little ethanol.

 

The antimalarial drug artemisinin and the specialty chemical β-farnesene are examples of natural product isoprenoids that can help solve global challenges, but whose usage has previously been limited by supply and cost impediments. This review describes the path to commercial production of these compounds utilizing fermentation of engineered yeast. Development of commercially viable yeast strains was a substantial challenge that was addressed by creation and implementation of an industrial synthetic biology pipeline. Using the engineered strains, production of β-farnesene from Brazilian sugarcane offers several environmental advantages. Among the many commercial applications of β-farnesene, its use as a feedstock for making biodegradable lubricants is highlighted. This example, along with others, highlight a powerful new suite of technologies that will become increasingly important for production of chemicals, spanning from pharmaceuticals through commodity chemicals.

 

STR1

Figure 2. Sanofi industrial semi-synthesis of artemisinin. The process starts with a moderate pressure catalytic diastereoselective hydrogenation of artemisinic acid to produce a high (95:5) ratio of the desired (R)-isomer. To avoid formation of a lactone byproduct, dihydro-epi-deoxyarteannuin B, during the photooxidation, the carboxylic acid is protected as a mixed anhydride. The final step combines formation of the intermediate hydroperoxide via photoxidation using a Hg vapor lamp and commercially available tetraphenylporphyin (TPP) as sensitizer with a Hock cleavage and rearrangement catalyzed by trifluoroacetic acid to give, after workup, the best yield reported to date of pure isolated artemisinin (55%).

Synthetic Biology and the Development of Commercial β-Farnesene Production Strains Semi-synthetic artemisinin is a pharmaceutical with a price point comparable to plant-derived artemisinin,20 namely above $150 per kg. β-Farnesene, however, is a specialty chemical with multiple uses (more details below); most specialty and commodity chemicals have significantly lower price points, often below $10 per kg. For these product categories, it is of paramount importance that fermentative production be as efficient as possible, with high yields (namely, grams of product made per gram of feed substrate), productivities (grams of product/liter of culture/hour) and concentration (also known as titer; grams of product per liter of culture). Developing yeast strains capable of the yield, productivity and titer required for chemical production requires extensive development, and has been enabled over the last decade by the new discipline of synthetic biology. Synthetic biology seeks to extend approaches and concepts from engineering and computation to redesign biology for a chosen function;21recent advances in the application of design automation, i.e., the use of software, hardware and robotics22 have enabled the creation and screening of hundreds of thousands of strain variants (created by both design and random mutagenesis) for the properties required for commercial production of β-farnesene. Notable enabling technologies developed for routine usage include rapid and reliable assembly of large (i.e., multiple kilobase) deoxyribonucleic acid (DNA) constructs;23-25 high throughput, cost effective, verification of structural DNA assemblies by both initial restriction digest26 and by low-cost DNA sequencing;27 and whole genome sequencing of yeast strains.28 In addition, there is a need to effectively identify the best new strains (akin to panning for gold!) through high throughput, rapid, and accurate methods to screen thousands of strains. Further, the results of small-scale (< 1 milliliter) tests must correspond to the results of large-scale (> 50,000 liter) production. Development and implementation of these technologies required considerable investment by Amyris. The outcome is a robust pipeline for efficient, cost-effective strain generation allied with screening for the properties required for commercial production of β-farnesene by fermentation (i.e., at a price point required for its use as a specialty chemical).

 

As the world’s population and economies grow, the demand for a wide variety of specialty, commodity, and pharmaceutical chemicals will outpace the supply available from current sources. There is an urgent need to develop alternative, sustainable sources of many existing chemicals and to develop abundant sources of currently scarce chemicals with novel beneficial properties. Synthetic biology and industrial fermentation, combined with synthetic chemistry, will be an increasingly important source of chemicals in the decades ahead; artemisinin and β-farnesene provide good examples of this relatively new approach to chemical production. Brazil’s plentiful sugar cane feedstock and fermentation expertise make it an excellent location for this type of manufacturing, which can expand and diversify the nation’s industrial base and international importance.

J. Braz. Chem. Soc. 2016, 27(8), 1339-1345

Developing Commercial Production of Semi-Synthetic Artemisinin, and of β-Farnesene, an Isoprenoid Produced by Fermentation of Brazilian Sugar

Kirsten R. Benjamin; Iris R. Silva; João P. Cherubim; Derek McPhee; Chris J. Paddon

How to cite this article

Genes encoding the biosynthetic pathway for production of a valuable product (e.g., farnesene) in a native organism are expressed in a heterologous microbial host (e.g., yeast). The engineered yeast produces farnesene by commercial fermentation. Copyright © 2016 Amyris, inc. All rights reserved.

http://dx.doi.org/10.5935/0103-5053.20160119

http://jbcs.sbq.org.br/imagebank/pdf/v27n8a04.pdf

Benjamin KR, Silva IR, Cherubim JP, Mcphee D, Paddon CJ. Developing Commercial Production of Semi-Synthetic Artemisinin, and of β-Farnesene, an Isoprenoid Produced by Fermentation of Brazilian Sugar. J. Braz. Chem. Soc. 2016;27(8):1339-1345

Kirsten R. Benjamin,a Iris R. Silva,b João P. Cherubim,c Derek McPheea and Chris J. Paddon*,a a Amyris, Inc., 5885 Hollis Street, Suite 100, CA 94608 Emeryville, USA b Amyris Brasil Ltda, Rua John Dalton 301-Bloco B-Edificio 3, Condominio Techno Plaza, 13069-330 Campinas-SP, Brazil c Amyris Brasil Ltda, Rodovia Brotas/Torrinha-km 7.5, 17380-000 Brotas-SP, Brazil

*e-mail: paddon@amyris.com
Chris Paddon

Chris Paddon, PhD

Dr. Paddon has a PhD in Biochemistry from Imperial College, London, but now considers himself a synthetic biologist. After postdoctoral work at the National Institutes of Health in Bethesda, MD, he worked in the pharmaceutical industry (GlaxoSmithKline), and then for two Bay Area biopharmaceutical companies (Affymax and Xenoport) before joining Amyris, Inc. in 2005 as its sixth employee and first scientist. He was project leader for the semi-synthetic artemisinin project at Amyris, Inc. and has subsequently led a number of other projects and programs there.

Chris Paddon is a Principal Scientist at Amyris, Inc. in Emeryville, CA. He was project leader for the Semi-Synthetic Artemisinin project, and subsequently led a number of projects at Amyris using synthetic biology for the production of natural products. He received his Bachelor’s degree in Microbiology from The University of Surrey (UK), and doctorate in Biochemistry from Imperial College (London, UK). Following postdoctoral work at The National Institutes for Health (Bethesda, MD) he joined the pharmaceutical industry, working for GSK (London, UK). He subsequently worked for Affymax (Palo Alto, CA) and Xenoport (Santa Clara, CA) before joining Amyris.

//////////// Commercial Production, Semi-Synthetic , Artemisinin,  farnesene, fermentation, natural product, lubricant

UCT Drug Discovery and Development Centre, H3D, pioneers world-class drug discovery in Africa.


H3D

UCT’s H3D is a center of excellence for research and innovation with an already strong track record in malaria drug  discovery. The vision of H3D is to be the leading organization for integrated drug discovery and development on the African continent.

ABOUT H3D

H3D is Africa’s first integrated drug discovery and development centre. The Centre was founded at the University of Cape Town in April 2011 and pioneers world-class drug discovery in Africa.

Our Vision

To be the leading organisation for integrated drug discovery and development from Africa, addressing global unmet medical needs.

Our Mission

To discover and develop innovative medicines for unmet medical needs on the African continent and beyond, by performing state-of-the-art research and development and bridging the gap between basic science and clinical studies.

We embrace partnerships with local and international governments, pharmaceutical companies, academia, and the private sector, as well as not-for-profit and philanthropic organisations, while  training scientists to be world experts in the field.

The H3D collaboration with the Medicines for Malaria Venture (MMV) focuses on delivering potential agents against malaria that will be affordable and safe to use. In line with the global aim to eradicate malaria, projects are pursued that not only eliminates blood-stage Plasmodium falciparum and Plasmodium vivax infection, but also acts against liver stages and blocks transmission of the infection. The projects embrace multidisciplinary activities to optimise hit compounds from screening libraries through the drug discovery pipeline and deliver clinical candidates.

Merck Serono Announces Recipients of the Second Annual €1 Million Grant for Multiple Sclerosis Innovation

Darmstadt, Germany, September 12, 2014 – Merck Serono, the biopharmaceutical division of Merck, today announced the recipients of the second annual Grant for Multiple Sclerosis Innovation (GMSI) at MS Boston 2014, the joint meeting of the Americas Committee for Treatment and Research in MS (ACTRIMS) and European Committee for Treatment and Research in MS (ECTRIMS), taking place September 10-13 in Boston, U.S.A.

Merck signed a research agreement with the University of Cape Town (UCT), South Africa, to co-develop a new R&D platform. It aims at identifying new lead programs for potential treatments against malaria, with the potential to expand it to other tropical diseases. It combines Merck’s R&D expertise and the drug discovery capabilities of the UCT Drug Discovery and Development Centre, H3D.
UCT’s H3D is a center of excellence for research and innovation with an already strong track record in malaria drug  discovery. The vision of H3D is to be the leading organization for integrated drug discovery and development on the African continent. They say that working with partners like Merck is critical to build up a comprehensive pipeline to tackle malaria and related infectious diseases.

Journal Publications:

  1. Aminopyrazolo[1,5-a]pyrimidines as potential inhibitors of Mycobacterium tuberculosis: Structure activity relationships and ADME characterization C. Soares de Melo, T-S. Feng, R. van der Westhuyzen, R.K. Gessner, L. Street, G. Morgans, D. Warner, A. Moosa, K. Naran, N. Lawrence, H. Boshoff, C. Barry, C. Harris, R. Gordon, K. Chibale. Biorg. Med. Chem. 2015, 23, 7240-7250.
  2. A Novel Pyrazolopyridine with in Vivo Activity in Plasmodium berghei- and Plasmodium falciparum- Infected Mouse Models from Structure−Activity Relationship Studies around the Core of Recently Identified Antimalarial Imidazopyridazines. C. Le Manach, T. Paquet, C. Brunschwig, M. Njoroge, Z. Han, D. Gonzàlez Cabrera, S. Bashyam, R. Dhinakaran, D. Taylor, J. Reader, M. Botha, A. Churchyard, S. Lauterbach, T. Coetzer, L-M. Birkholtz, S. Meister, E. Winzeler, D. Waterson, M. Witty, S. Wittlin, M-B. Jiménez-Díaz, M. Santos Martínez, S. Ferrer, I. Angulo-Barturen, L. Street, and K. Chibale, J. Med. Chem. 2015, XX, XXXX
  3. Structure−Activity Relationship Studies of Orally Active Antimalarial 2,4-Diamino-thienopyrimidines. D. Gonzàlez Cabrera, F. Douelle, C. Le Manach, Z. Han, T. Paquet, D. Taylor, M. Njoroge, N. Lawrence, L. Wiesner, D. Waterson, M. Witty, S. Wittlin, L. Street and K. Chibale. J Med Chem. 2015, 58, 7572-7579.
  4. Medicinal Chemistry Optimization of Antiplasmodial Imidazopyridazine Hits from High Throughput Screening of a SoftFocus Kinase Library: Part 2. Le Manach, T. Paquet, D. Gonzalez Cabrera, Y. Younis, D. Taylor, L. Wiesner, N. Lawrence, S. Schwager, D. Waterson, M.J. Witty, S. Wittlin, L. Street, and K. Chibale. J. Med. Chem. 2014, 57, 8839−8848.
  5. Medicinal Chemistry Optimization of Antiplasmodial Imidazopyridazine Hits from High Throughput Screening of a SoftFocus Kinase Library: Part 1. Le Manach, D. González Cabrera, F. Douelle, A.T. Nchinda, Y. Younis, D. Taylor, L. Wiesner, K. White, E. Ryan, C. March, S. Duffy, V. Avery, D. Waterson, M. J. Witty, S. Wittlin; S. Charman, L. Street, and K. Chibale. J. Med. Chem. 2014, 57, 2789-2798.
  6. 2,4-Diamino-thienopyrimidines as Orally Active Antimalarial Agents. D. González Cabrera, C. Le Manach, F. Douelle, Y. Younis, T.-S. Feng, T. Paquet, A.T. Nchinda, L.J. Street, D. Taylor, C. de Kock, L. Wiesner, S. Duffy, K.L. White, K.M. Zabiulla, Y. Sambandan, S. Bashyam, D. Waterson, M.J. Witty, A. Charman, V.M. Avery, S. Wittlin, and K. Chibale. J. Med. Chem. 2014,57, 1014-1022.
  7. Effects of a domain-selective ACE inhibitor in a mouse model of chronic angiotensin II-dependent hypertension. Burger, T.L. Reudelhuber, A. Mahajan, K. Chibale,E.D. Sturrock, R.M. Touyz. Clin. Sci. (Lond). 2014, 127(1), 57-63.
  8. Pharmacokinetic evaluation of lisinopril-tryptophan, a novel C-domain ACE inhibitor. Denti, S.K. Sharp, W.L. Kröger, S.L. Schwager, A. Mahajan, M. Njoroge, L. Gibhard, I. Smit, K. Chibale, L. Wiesner, E.D. Sturrock, N.H. Davies. Eur. J. Pharm. Sci.2014, 56, 113-119.
  9. Fragment-based design for the development of N-domain-selective angiotensin-1-converting enzyme inhibitors. R.G. Douglas, R.K. Sharma, G. Masuyer, L. Lubbe, I. Zamora, K.R. Acharya, K. Chibale, E.D. Sturrock. Sci. (Lond). 2014, 126(4),305-313.
  10. Fast in vitro methods to determine the speed of action and the stage-specificity of anti-malarials in Plasmodium falciparum. Le Manach, C. Scheurer, S. Sax, S. Schleiferböck, D. González Cabrera, Y. Younis, T. Paquet, L. Street, P.J. Smith, X. Ding, D. Waterson, M.J. Witty, D. Leroy, K. Chibale and S. Wittlin*. Malaria Journal, 2013, 12, 424.
  11. Structure-Activity-Relationship Studies Around the 2-Amino Group and Pyridine Core of Antimalarial 3,5-Diarylaminopyridines Lead to a Novel Series of Pyrazine Analogues with Oral in vivo Activity. Y. Younis, F. Douelle, González Cabrera, C. Le Manach, A.T. Nchinda, T. Paquet, L.J. Street, K.L. White, K. M. Zabiulla, J.T. Joseph,  S. Bashyam, D. Waterson, M.J. Witty, S. Wittlin, S.A. Charman, and K. Chibale*   J. Med. Chem. 2013, 56, 8860−8871.
  12. Cell-based Medicinal Chemistry Optimization of High Throughput Screening (HTS) Hits for Orally Active Antimalarials-Part 2: Hits from SoftFocus Kinase and other Libraries. Y. Younis, L. J. Street, D. Waterson, M.J. Witty, and K. Chibale. J. Med. Chem. 2013, 56, 7750−7754.
  13. Structure-Activity Relationship Studies of Orally active Antimalarial 3,5-Substituted 2-Aminopyridines. D. González Cabrera, F. Douelle, Y. Younis, T.-S. Feng, C. Le Manach, A.T. Nchinda, L.J. Street, C. Scheurer, J. Kamber, K. White, O. Montagnat, E. Ryan, K. Katneni, K.M. Zabiulla, J. Joseph, S. Bashyam, D. Waterson, M.J. Witty, S. Charman, S. Wittlin, and K. Chibale* J. Med. Chem. 2012, 55, 11022– 11030.
  14. 3,5-Diaryl-2-aminopyridines as a Novel Class of Orally Active Antimalarials Demonstrating Single Dose Cure in Mice and Clinical Candidate Potential. Y. Younis, F. Douelle, T.-S. Feng, D. González Cabrera, C. Le Manach, A.T. Nchinda, S. Duffy, K.L. White, M. Shackleford,  J. Morizzi, J. Mannila, K. Katneni, R. Bhamidipati, K. M. Zabiulla, J.T. Joseph,  S. Bashyam, D. Waterson, M.J. Witty, D. Hardick, S. Wittlin, V. Avery, S.A. Charman, and K. Chibale*.  J. Med. Chem.  2012, 55, 3479−3487.
  15. Novel Orally Active Antimalarial Thiazoles. D. González Cabrera, F. Douelle, T.-S Feng, A.T. Nchinda, Y. Younis, K.L. White, Wu,E. Ryan, J.N. Burrows,D. Waterson, M.J. Witty,S. Wittlin,S.A. Charman and K. Chibale.  J. Med. Chem. 2011, 54, 7713–7719.
  16. Synthesis and molecular modeling of a lisinopril-tryptophan analogue inhibitor of angiotensin I-converting enzyme. A.T. Nchinda, K. Chibale, P. Redelinghuys and E.D. Sturrock. Med. Chem. Lett. 2006, 16(17), 4616-4619.

Patents

  1. Anti-Malarial Agents. Y. Younis, K. Chibale, M.J. Witty, D. Waterson. (2016) US9266842 B2.
  2. New Anti-Malarial Agents. D. Waterson, M.J. Witty, K. Chibale, L. Street, D. González Cabrera, T. Paquet. EP patent application (2015), No. 15 176 514.6.
  3. Preparation of aminopyrazine compounds as antimalarial agents for treatment of malaria. Y. Younis, K. Chibale, M.J. Witty, D. Waterson. PCT Int Appl. (2013), WO 2013121387 A1 20130822.
  4. Preparation of peptides as angiotensin I-converting enzyme (ACE) inhibitors. E.D. Sturrock, A.T. Nchinda, K. Chibale. PCT Int. ppl. (2006), WO 2006126087 A2 20061130.
  5. Preparation of peptides as angiotensin I-converting enzyme (ACE) inhibitors, E.D. Sturrock, A.T. Nchinda, K. Chibale. PCT Int. ppl. (2006), WO 2006126086 A2 20061130.

Head Office, Medicinal Chemistry Unit

Physical Address:
Department of Chemistry
7.32 H3D Lab Suite, PD Hahn Building, Level 7
North Lane off Ring Road
Upper Campus, University of Cape Town
Rondebosch, 7700, South Africa

T | 021 650 5495
F | 021 650 5195

Postal Address:
University of Cape Town
Private Bag X3
Rondebosch 7701
South Africa

P. D. Hahn Bldg, Rondebosch, Cape Town,
Map of P. D. Hahn Bldg, Rondebosch, Cape Town, 7700, South Africa
P. D. Hahn Bldg, Rondebosch, Cape Town, 7700, South Africa

//////H3D, Africa,  integrated drug discovery and development centre,  University of Cape Town 

Recovery of Artemisinin from a Complex Reaction Mixture Using Continuous Chromatography and Crystallization


Figure

Figure

Recovery of Artemisinin from a Complex Reaction Mixture Using Continuous Chromatography and Crystallization

Articles ASAP (As Soon As Publishable)
Publication Date (Web): May 8, 2015 (Article)
DOI: 10.1021/acs.oprd.5b00048
*E-mail: seidel-morgenstern@mpi-magdeburg.mpg.de. Tel.: +49-(0)391-6110 401. Fax: +49-(0)391-6110 521.
Artemisinin, a secondary metabolite of sweet wormwood, is the basis for the production of the most effective antimalarial drugs. Since the amount of artemisinin currently produced from plants is not sufficient to treat the worldwide malaria cases, an effective semisynthetic method was developed recently that is capable of producing artemisinin from dihydroartemisinic acid (DHAA). DHAA is a byproduct obtained during the extraction of artemisinin from plant leaves. The photocatalytic reaction to convert DHAA to artemisinin can be performed continuously in a tubular reactor using toluene as a solvent. The reactor effluent contains besides artemisinin the photocatalyst (dicyanoanthracene) and several compounds that are structurally similar to artemisinin, including unreacted DHAA starting material. To isolate artemisinin from the reaction mixture, two separation techniques were applied, crystallization and chromatography. The solid obtained by seeded cooling crystallization was highly enriched in artemisinin but contained also traces of the photocatalyst. In contrast, using a variant of continuously operated multicolumn simulated moving bed (SMB) chromatography, which splits the feed into three fractions, we were able to recover efficiently the photocatalyst in the raffinate stream. The extract stream provided already almost pure artemisinin, which could be finally further purified in a simple crystallization step.
Magdeburg, Germany
Map of magdeburg germany
 
 
 
 

Arteflene


Arteflene
Arteflene
CAS : 123407-36-3 (Z-form)
 [1S-[1a,4b(Z),5a,8b]]-4-[2-[2,4-Bis(trifluoromethyl)phenyl]ethenyl]-4,8-dimethyl-2,3-dioxabicyclo[3.3.1]nonan-7-one
(1S,4R,5R,8S)-4-[(Z)-2,4-bis(trifluoromethyl)styryl]-4,8-dimethyl-2,3-dioxabicyclo[3.3.1]nonan-7-one
(1S,4R,5R,8S)-4-[(Z)-2,4-Bis(trifluoromethyl)styryl]-4,8-dimethyl-2,3-dioxabicyclo[3.3.1]nonan-7-one
Manufacturers’ Codes: Ro-42-1611
Properties: Crystalline stable material, mp 124°. Highly lipophilic, not sol in water. Stable in soln except in the presence of strong bases or strong reducing agents.
Melting point: mp 124°
Therap-Cat: Antimalarial
 
The oxidation of (5R)-(-)-carvone (I) with 3-chloroperbenzoic acid (3-CPB) in dichloromethane gives 5(R)-acetyl-2-methyl-2-cyclohexen-1-one (II), which is condensed with ethyltriphenylphosphonium bromide (III) by means of butyllithium in THF yielding 2-methyl-5(Z)-(1-methyl-1-propenyl)-2-cyclohexen-1-one (IV). The photochemical oxidation of (IV) in acetonitrile catalyzed by methylene blue affords (1R,4RS,5R,8S)-4,8-dimethyl-4-vinyl-2,3-dioxabicyclo[3.3.1]nonan-7-one (V), which is ozonolyzed with O3 in methanol to the corresponding aldehyde as a mixture of enantiomers, which is submitted to crystallization giving the (1S,4R,5R,8S)-isomer (VI). Finally, this compound is submitted to a Wittig condensation with 2,4-bis(trifluoromethyl)benzyltriphenylphosphonium bromide (VII) by means of sodium bis(trimethylsilyl)amide (NaBTSA) in dichloromethane.
……………………….
Literature References:
Synthetic sesquiterpene peroxide; structurally derived from the natural peroxides artemisinin, q.v. and yingzhaosu. Prepn: W. Hofheinz et al., EP 311955; eidem, US 4977184 (1989, 1990 both to Hoffmann-La Roche).
Series of articles on prepn, biological activities, pharmacokinetics and clinical evaluations: Trop. Med. Parasitol. 45, 261-291 (1994).

KAE 609, NITD 609, Cipargamin for Malaria


 

NITD609.svg
Cipargamin, NITD 609
IUPAC Name: (3R,3’S)-5,7′-dichloro-6′-fluoro-3′-methylspiro[1H-indole-3,1′-2,3,4,9-tetrahydropyrido[3,4-b]indole]-2-one |
CAS Registry Number: 1193314-23-6
Synonyms: NITD609, NITD 609, NITD-609, GNF-609
KAE-609
NITD-609  
 390.238, C19 H14 Cl2 F N3 O
(1’R,3’S)-5,7′-Dichloro-6′-fluoro-3′-methyl-1,2,2′,3′,4′,9′-hexahydrospiro[indole-3,1′-pyrido[3,4-b]indole]-2-one
(1R,3S)-5′,7-Dichloro-6-fluoro-3-methyl-2,3,4,9-tetrahydrospiro[β-carboline-1,3′-indol]-2′(1′H)-one
CURRENTLY IN -PHASE2
NITD609 is an experimental synthetic antimalarial molecule belonging to the spiroindolone class.[1][2] The compound was developed at the Novartis Institute for Tropical Diseases in Singapore, through a collaboration with the Genomics Institute of the Novartis Research Foundation (GNF), the Biomedical Primate Research Centre and the Swiss Tropical Institute. NITD609 is a novel, synthetic antimalarial molecule belonging to the spiroindolone class, awarded MMV Project of the Year 2009.
It is structurally related to GNF 493, a compound first identified as a potent inhibitor of Plasmodium falciparum growth in a high throughput phenotypic screen of natural products conducted at the Genomics Institute of the Novartis Research Foundation in San Diego, California in 2006. NITD609 was discovered by screening the Novartis library of 12,000 natural products and synthetic compounds to find compounds active against Plasmodium falciparum. The first screen turned up 275 compounds and the list was narrowed to 17 potential candidates.
KAE609 (cipargamin; formerly NITD609, Novartis Institute for Tropical Diseases) is a new synthetic antimalarial spiroindolone analogue with potent, dose-dependent antimalarial activity against asexual and sexual stages of Plasmodium falciparum.http://www.nejm.org/doi/full/10.1056/NEJMoa1315860
ChemSpider 2D Image | cipargamin | C19H14Cl2FN3O

KAE609 shows promise as next generation treatment for malaria

http://www.novartis.com/newsroom/media-releases/en/2014/1843976.shtml

  • KAE609 is the first antimalarial drug candidate with a novel mechanism of action to achieve positive clinical proof-of-concept in over 20 years
  • KAE609 was tested in adult patients with uncomplicated malaria and showed a median parasite clearance time of 12 hours, including in patients with resistant infections[1]
  • For more than a decade, Novartis has been a leader in the fight against malaria, setting the current gold standard for treatment and building one of the strongest malaria pipelines in the industry

KAE609 shows promise as next generation treatment for malaria

  • KAE609 is the first antimalarial drug candidate with a novel mechanism of action to achieve positive clinical proof-of-concept in over 20 years
  • KAE609 was tested in adult patients with uncomplicated malaria and showed a median parasite clearance time of 12 hours, including in patients with resistant infections[1]
  • For more than a decade, Novartis has been a leader in the fight against malaria, setting the current gold standard for treatment and building one of the strongest malaria pipelines in the industry

The digital press release with multimedia content can be accessed here:

Basel, Switzerland, July 30, 2014 Today, Novartis published clinical trial results in the New England Journal of Medicine showing that KAE609 (cipargamin), a novel and potent antimalarial drug candidate, cleared the parasite rapidly in Plasmodium falciparum (P. falciparum) and Plasmodium vivax (P. vivax) uncomplicated malaria patients[1]. Novartis currently has two drug candidates in development. Both KAE609 and KAF156 are new classes of anti-malarial compounds that treat malaria in different ways from current therapies, important to combat emerging drug resistance. Novartis has also identified PI4K as a new drug target with potential to prevent, block and treat malaria.

“Novartis is in the fight against malaria for the long term and we are committed to the continued research and development of new therapies to eventually eliminate the disease,” said Joseph Jimenez, CEO of Novartis. “With two compounds and a new drug target currently under investigation, Novartis has one of the strongest malaria pipelines in the industry.”

Malaria is a life-threatening disease primarily caused by parasites (P. falciparum and P. vivax) transmitted to people through the bites of infected Anopheles mosquitoes. Each year it kills more than 600,000 people, most of them African children[2].

“KAE609 is a potential game-changing therapy in the fight against malaria,” said Thierry Diagana, Head of the Novartis Institute for Tropical Diseases (NITD), which aims to discover novel treatments and prevention methods for major tropical diseases. “Novartis has given KAE609 priority project status because of its unique potential of administering it as a single-dose combination therapy.”

In June 2012, 21 patients infected by one of the two main malaria-causing parasite types took part in a proof-of-concept clinical study conducted in Bangkok and Mae Sot near the Thailand/Burma border where resistance to current therapies had been reported. Researchers saw rapid parasite clearance in adult patients (median of 12 hours)[2] with uncomplicated P. vivax or P. falciparum malaria infection including those with resistant parasites. No safety concerns were identified, however the study was too small for any safety conclusions.

“The growing menace of artemisinin resistance threatens our current antimalarial treatments, and therefore our attempts to control and eliminate falciparum malaria,” said Nick White, Professor of Tropical Medicine at Mahidol University in Thailand and lead author of the NEJM article. “This is why we are so enthusiastic about KAE609; it is the first new antimalarial drug candidate with a completely novel mechanism of action to reach Phase 2 clinical development in over 20 years.”

KAE609, the first compound in the spiroindolone class of treatment, works through a novel mechanism of action that involves inhibition of a P-type cation-transporter ATPase4 (PfATP4), which regulates sodium concentration in the parasite. Because KAE609 also appears to be effective against the sexual forms of the parasite, it could potentially help prevent disease transmission. The clinical trial was done in collaboration with the Wellcome Trust-Mahidol University – Oxford Tropical Medicine Research Programme. Research was supported by the Wellcome Trust, Singapore Economic Development Board, and Medicines for Malaria Venture.

KAE609 represents one of two new classes of antimalarial compounds that Novartis has discovered and published in the last four years.[3],[4] This drug candidate has shown potent in vitro activity against a broad range of parasites that have developed drug resistance against current therapies. KAE609 is currently being planned for Phase 2b trials.

References
[1] http://www.nejm.org/doi/full/10.1056/NEJMoa1315860
[2] World Health Organization, http://www.who.int/mediacentre/factsheets/fs094/en/
[3] Spiroindolones, a Potent Compound Class for the Treatment of Malaria, KAE609, Science, Sept. 2010
[4] Imaging of Plasmodium liver stages to drive next generation antimalarial drug discovery. Science Express, Nov. 17, 2011

http://www.ukmi.nhs.uk/applications/ndo/record_view_open.asp?newDrugID=6368

The current spiroindolone was optimized to address its metabolic liabilities leading to improved stability and exposure levels in animals. As a result, NITD609 is one of only a handful of molecules capable of completely curing mice infected withPlasmodium berghei (a model of blood-stage malaria).
Given its good physicochemical properties, promising pharmacokinetic and efficacy profile, the molecule was recently approved as a preclinical candidate and is now entering GLP toxicology studies with the aim of entering Phase I studies in humans in late 2010. If its safety and tolerability are acceptable, NITD609 would be the first antimalarial not belonging to either the artemisinin or peroxide class to go into a proof-of-concept study in malaria.
If NITD609 behaves similarly in people to the way it works in mice, it may be possible to develop it into a drug that could be taken just once – far easier than current standard treatments in which malaria drugs are taken between one and four times a day for up to seven days. NITD609 also has properties which could enable it to be manufactured in pill form and in large quantities. Further animal studies have been performed and researchers have begun human-stage trials.
NITD609
NITD609.svg
Identifiers
ChemSpider 24662493
Jmol-3D images Image 1
Properties
Molecular formula C19H14Cl2FN3O
Molar mass 390.24 g mol−1

Malaria is an old infectious disease caused by four protozoan parasites, Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae and Plasmodium ovale. These four parasites are typically transmitted by the bite of an infected female Anopheles mosquito. Malaria is a problem in many parts of the world, and over the last few decades the malaria burden has steadily increased. An estimated 1 to 3 million people die every year from malaria – mostly children under the age of 5. This increase in malaria mortality is due in part to the fact that Plasmodium falciparum, the deadliest malaria parasite, has acquired resistance against nearly all available antimalarial drugs, with the exception of the artemisinin derivatives.

Leishmaniasis is caused by one of more than twenty (20) varieties of parasitic protozoa that belong to the genus Leishmania, and is transmitted by the bite of female sandflies. Leishmaniasis is endemic in some 90 countries, including many tropical and sub-tropical areas.

There are four main forms of leishmaniasis. Visceral leishmaniasis, also called kala-azar, is the most serious form and is caused by the parasite Leishmania donovani. Patients who develop visceral leishmaniasis can die within months unless they receive treatment. The two main therapies for visceral leishmaniasis are the antimony derivatives sodium stibogluconate (Pentostam®) and meglumine antimoniate (Glucantim®). Sodium stibogluconate has been used for about 70 years and resistance to this drug is a growing problem. In addition, the treatment is relatively long and painful, and can cause undesirable side effects. Human African Trypanosomiasis, also known as sleeping sickness, is a vector-bome parasitic disease. The parasites concerned are protozoa belonging to the Trypanosoma Genus. They are transmitted to humans by tsetse fly {Glossina Genus) bites which have acquired their infection from human beings or from animals harbouring the human pathogenic parasites.

Chagas disease (also called American trypanosomiasis) is another human parasitic disease that is endemic amongst poor populations on the American continent. The disease is caused by the protozoan parasite Trypanosoma cruzi, which is transmitted to humans by blood-sucking insects. The human disease occurs in two stages: the acute stage, which occurs shortly after the infection, and the chronic stage, which can develop over many years. Chronic infections result in various neurological disorders, including dementia, damage to the heart muscle and sometimes dilation of the digestive tract, as well as weight loss. Untreated, the chronic disease is often fatal.

The drugs currently available for treating Chagas disease are nifurtimox and benznidazole. However, problems with these current therapies include their adverse side effects, the length of treatment, and the requirement for medical supervision during treatment. Furthermore, treatment is really only effective when given during the acute stage of the disease. Resistance to the two frontline drugs has already arisen. The antifungal agent amphotericin b has been proposed as a second-line drug, but this drug is costly and relatively toxic.

PAPER

Stereoselective Total Synthesis of KAE609 via Direct Catalytic Asymmetric Alkynylation to Ketimine

Institute of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan
JST, ACT-C, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo 141-0021, Japan
Org. Lett., 2015, 17 (19), pp 4762–4765
DOI: 10.1021/acs.orglett.5b02300
Publication Date (Web): September 14, 2015
Copyright © 2015 American Chemical Society

Abstract

Abstract Image

A direct catalytic asymmetric alkynylation protocol is applied to provide the requisite enantioenriched propargylic α-tertiary amine, allowing for the stereoselective total synthesis of KAE609 (formerly NITD609 or cipargamin).

STR1

STR1

CLICK ON IMAGE TO VIEW

http://pubs.acs.org/doi/abs/10.1021/acs.orglett.5b02300?journalCode=orlef7

http://pubs.acs.org/doi/suppl/10.1021/acs.orglett.5b02300/suppl_file/ol5b02300_si_001.pdf

 

 STR1.jpg
STR1.jpg

PATENT

WO 2009/132921

Figure

In this process, the chiral amine is installed via an enzymatic resolution via deacylation of the acetamide 2. In addition to the wasteful resolution, other inefficiencies of this route include protection/deprotection (Ac/Boc, 2 to 4, and 5 to 6) and a three-step sequence to reduce the carboxylic acid to a methyl group (3 to 6).

Patent

US 2015/0045562

Figure

Improved Route to Cipargamin Employing Transaminase Reaction

For the transamination step, the enzyme ATA-256 was engineered by Codexis to accommodate the non-natural indole substrate 12. Since the substrate is not water-soluble, PEG 200 (approximately 20 vol %) is used as a cosolvent, an interesting selection given that DMSO or methanol are the most common cosolvents for enzymatic reactions. Isopropylamine is employed as the amine donor, a strategy that was adopted from the work of Merck and Codexis for the transamination of sitagliptin ketone.(2) During the transamination, which is a reversible reaction,i-PrNH2 is converted to acetone, which can be readily removed by evaporation to drive the reaction to completion. The workup involves filtration to remove enzyme residues followed by pH swings in which the product is extracted into the aqueous layer under acidic conditions, then basified for extraction into the organic layer. Addition of (+)-camphorsulfonic acid (CSA) provides the amine 14 as the crystalline CSA salt. No details are provided on enantioselectivity for the transamination, and it is not clear if the (+)-CSA is required to upgrade the ee or whether this salt was selected based on physical properties and the ability to develop a scalable crystallization process.
The final step to generate the spiroindole involves a diastereoselective condensation of the chiral amine with 5-chloroisatin (7) under acidic conditions. The diastereoselectivity of this reaction is not provided, nor any ee or de data for the final product. The spiroindole is also isolated as a (+)-CSA salt, which is then converted to the crystalline free base hemihydrate as the final form of cipargamin.

Example 12: Process for Preparing a Compound of formula (IVA) 1/z Hydrate

622.54 399.25

In a 750ml reactor with impeller stirrer 50g of compound (IVB) salt were dissolved in 300ml Ethanol (ALABD) and 100 ml deionised Water (WEM). The clear, yellowish sollution was heated to 58°C internal temperature. To the solution 85 g of a 10% aqueous sodium carbonate solution was added within 10 minutes. The clear solution was particle filtered into a second reaction vessel. Vessel and particle filter were each rinsed with 25 ml of a mixture of ethanohwater (3:1 v/v) in the second reaction vessel. The combined particle filtered solution is heated to 58°C internal temperature and 200ml water (WEM) were added dropwise within 15 minutes. Towards the end of the addition the solution gets turbid. The mixture is stirred for 10 minutes at 58°C internal temperature and is then cooled slowely to room temperature within 4hours 30 minutes forming a thick, well stirable white suspension. To the suspension 200 ml water are added and the mixture is stirred for additional 15hours 20 minutes at room temperature. The suspension is filtered and the filter cake is washed twice with 25 ml portions of a mixture of ethanohwater 9: 1 (v/v). The colourless crystals are dried at 60°C in vacuum yielding 26.23g (=91.2% yield). H NMR (400 MHz, DMSO-d6)

0.70 (s, 1H), 10.52 (s, 1H), 7.44 (d, J = 10.0 Hz, 1H), 7.33 (dd, J = 8.4, 2.1 Hz, 1H),.26 (d, J = 6.5 Hz, 1H), 7.05 (d, J = 2.3 Hz, 1H), 6.93 (d, J = 8.3 Hz, 1H), 3.83 – 4.00 (m,H), 3.13 (d, J = 6.0 Hz, 1H), 2.77 (dd, J = 15.1, 3.8 Hz, 1H), 2.38 (dd, J = 15.1, 10.5 Hz,H), 1.17 (d, J = 6.3 Hz, 3H).

 

 

Patent

http://www.google.com/patents/WO2009132921A1?cl=en

 

SCHEME G: Preparation of (lR,3S)-5′,7-dichloro-6-fluoro-3-methyl-2,3,4,9- tetrahydrospiro[β-carboline-l,3′-indol-2′(l’iϊ)-one (35) and (lR,3S)-5′-chloro-6-fluoro-3- methyl-2,3,4,9-tetrahydrospiro[β-carboline-l,3′-indoI-2′(l’H0-one (36)

Step 1 : POCl3 (2.43 mL, 26.53 mmol) was added dropwise to N, N-dimethylformamide (15.0 mL) at -20 °C and stirred below -5 0C for one hour. A solution of 6-chloro-5-fluoroindole (3.0 g, 17.69 mmol) in dimethylformamide (5.0 mL) was added dropwise to the above reaction mixture at -20 °C. The salt-ice bath was removed and the reaction mixture was warmed to 35 0C, After one hour, the reaction was poured onto ice and basified by solid sodium bicarbonate and extracted with ethyl acetate. The combined organic layer was washed with water and then concentrated to give 6-chloro-5-fluoro-1H-indole-3-carbaldehyde (3.4 g, 97 %) as a light brown solid. 1H ΝMR (500 MHz, CDCl3): δ 10.02 (s, 1 H), 8.10 (d, IH, J = 9.5 Hz), 7.87 (s, 1 H), 7.49 (d, IH, J= 5.5 Hz).

Step 2: The solution (0.2 M) of 6-chloro-5-fluoro-1H-indole-3-carbaldehyde (4.0 g, 20.24 mmol) in nitroethane (100 mL) was refluxed with ammonium acetate (1.32 g, 0.85 mmol) for 4 hours. The reaction mixture was concentrated under vacuum to remove nitroethane, diluted with ethylacetate and washed with brine. The organic layer was concentrated to give 6-chloro-5- fluoro-3-(2-nitro-propenyl)-1H-indole (5.0 g, 97 %) as a reddish orange solid. 1H ΝMR (500 MHz, CDCl3): δ 8.77 (s, IH), 8.32 (s, IH), 7.58 (d, IH, J= 2.5 Hz), 7.54 (d, IH, J = 9 Hz), 7.50 (d, IH, J= 5.9 Hz), 2.52 (s, 3H). Step 3: A solution of 6-chloro-5-fluoro-3-(2-nitro-propenyl)-1H-indole (5.0 g, 19.63 mmol) in tetrahydrofuran (10 mL) was added to the suspension of lithium aluminium hydride (2.92 g, 78.54 mmol) in tetrahydrofuran (20 mL) at 0 0C and then refluxed for 3 hours. The reaction mixture was cooled to 0 °C, and quenched according to the Fischer method. The reaction mixture was filtered through celite and the filtrate concentrated to give 2-(6-chloro-5-fluoro-1H-indol-3- yl-1-methyl-ethylamine (4.7 g crude) as a viscous brown liquid. The residue was used without further purification. 1H NMR (500 MHz, CDCl3): δ 8.13 (s, IH), 7.37 (d, IH, 6.Hz), 7.32 (d, IH, J = 10 Hz), 7.08 (s, IH), 3.23-3.26 (m, IH), 2.77-2.81 (m, IH), 2.58-2.63 (m, IH), 1.15 (d, 3H, J= 6.5 Hz).

Step 4: A mixture of 2-(6-chloro-5-fluoro-1H-indol-3-yl-l-methyl-ethylamine (4.7 g, 20.73 mmol), 5-chloroisatin (3.76 g, 20.73 mmol) and p-toluenesulphonic acid (394 mg, 2.07 mmol) in ethanol (75 mL) was refluxed overnight. The reaction mixture was concentrated to remove ethanol, diluted with ethyl acetate and washed with saturated aqueous NaHCO3. The organic layer was concentrated to give a brown residue, which was purified by silica gel chromatography (20 % ethyl acetate in hexane) to provide the corresponding racemate (4.5 g, 56 %) as a light yellow solid. The racemate was separated into its enantiomers by chiral chromatography to provide 35.

Compound 36 can be obtained in a similar fashion from 5-fluoroindole.

Alternatively 35 and 36 were be prepared in enantiomerically pure form by the following scheme.

SCHEME H: Alternative preparation of (lR,3S)-5′,7-dichloro-6-fluoro-3-methyl-2,3,4,9- tetrahydrospiro[β-carboline-l,3′-indol-2′(1’H)-one (35)

Step 1 : To a solution of 6-chloro-5-fluoroindole (1.8 g, 10.8 mmol) and Ac2O (10 niL) in AcOH (3OmL) was added L-serine (2.2 g, 20.9 mmol), the mixture was heated to 80 °C. After TLC indicated the reaction was complete, the mixture was cooled to 0 °C, neutralized to pH 11 , and washed with MTBE. The aqueous phase was acidified to pH 2 and extracted with EtOAc. The combined organic layers were washed with water and bπne, dπed with Na2SO4, filtered, and concentrated. The residue was purified with chromatography (Petroleum ether /EtOAc 1:1) to give 2-acetylamino-3-(6-chloro-5-fluoro-1H-mdol-3-yl)-propπonic acid as a light yellow solid (1.2 g, 37% yield).

Step 2: 2-Acetylamino-3-(6-chloro-5-fluoro-1H-indol-3-yl)-proprionic acid (2.5g, 8.4mmol) was dissolved in aqueous NaOH (IN, 10 niL) and water added (70 mL). The mixture was heated to 37-380C and neutralized with HCl (IN) to pΗ 7.3-7.8. L-Aminoacylase (0.5 g) was added to the mixture and allowed to stir for 2 days, maintaining 37-380C and pΗ 7.3-7.8. The mixture was heated to 60 °C for another hour, concentrated to remove part of water, cooled and filtered. The filtrate was adjusted to pΗ 5.89 and filtered again. The filtrate was adjusted to pΗ 2.0 and extracted with EtOAc. The combined organic layer was dried over Na2SO4, filtered, concentrated and the residue was purified with chromatography (petroleum ether /EtOAc 1 : IEtOAc) to give R- 2-acetylamino-3-(6-chloro-5-fluoro-1H-mdol-3-yl)-propπonic acid as a light yellow solid (1.2 g, 48% yield). Step 3: R-2-acetylamino-3-(6-chloro-5-fluoro-1H-indol-3-yl)-proprionic acid (1.2 g, 4.0 mmol) was dissolved in HCl (6N, 10 mL) and the mixture heated to reflux for 4 hours, and then concentrated to dryness. Toluene (50 mL) was added to the residue and concentrated to dryness to remove water and HCl. The residue was dried under vacuum and then dissolved in MeOH (20 mL). To the solution was added dropwise SOCl2 (0.5 mL, 6.8 mmol) at 0 °C, and the mixture was stirred overnight. After removal of solvent, the residue was dissolved in THF/water (40/10 mL) and NaHCO3 (1.0 g, 11.9 mmol) was added portionwise. Upon basifϊcation, BoC2O (1.2 g, 5.5 mmol) added at 0 °C and allowed to stir at room temperature. After TLC indicated the reaction was finished, EtOAc was added and separated and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with water and brine, dried with Na2SO4, filtered, concentrated and the residue was purified with chromatography (petroleum ether /EtOAc: 5/1) to give R-2-tert-butoxycarbonylamino-3-(6-chloro-5-fluoro-l/-/-indol-3-yl)-proprionic acid methyl ester 460 g, 31% yield for 3 steps).

Step 4: To a solution of R-2-tert-butoxycarbonylamino-3-(6-chloro-5-fluoro-l//-indol-3-yl)- proprionic acid methyl ester (460mg, 1.2mmol) in dry ether (20 mL) was added portionwise LiAlH4 (92 mg, 2.4 mmol) at 0 °C. The mixture was heated to reflux for 2 hours. After TLC indicated the reaction was finished, the mixture was cooled and carefully quenched with Na2SO4. The mixture was filtered and the filtrate was washed with saturated aqueous NH4Cl and water, dried with Na2SO4, filtered, concentrated to give a crude product (400 mg), which was used without further purification.

Step 5: To a solution of the crude product (400 mg, 1.2mmol) and Et3N (0.3 mL, 2.2 mmol) in CH2Cl2 (5 mL) was added MsCl (160 mg, 1.4 mmol) dropwise at 0 °C. The mixture was stirred for 2 hours at room temperature. After TLC indicated the reaction was completed, the mixture was washed with water and brine, dried with Na2SO4, filtered, concentrated and the residue was purified with chromatography (petroleum ether/EtOAc 5:1) to give methansulfonic acid (R)-2- ?ert-butoxycarbonylamino-3-(6-chloro-5-fluoro-1H-indol-3-yl)-propyl ester as a light yellow solid (300 mg, 57% yield, 2 steps)

Step 6: To a solution of mesylate (300 mg, 0.7mmol) in dry ether (20 mL) was added portionwise LiAlH4 (55 mg, 1.4 mmol) at 0 °C. The mixture was stirred at room temperature overnight. After TLC indicated the reaction was finished, the mixture was cooled and carefully quenched with Na2SO4. The mixture was filtered and the filtrate was washed with saturated aqueous NH4Cl and water, dried with Na2SO4, filtered, concentrated and the residue was purified with chromatography (petroleum ether/EtOAc 10: 1) to give [(5)-2-(6-chloro-5-fluoro-1H-indol-3-yl)- 1 -methyl-ethyl] -carbamic acid tert-butyl ester as a light yellow solid (200 mg, 87% yield).

Step 7: A solution of [(S)-2-(6-chloro-5-fluoro-1H-indol-3-yl)-l-methyl-ethyl]-carbamic acid tert-butyl ester (200 mg, 0.6 mmol) in HCl/MeOH (10 mL) was stirred at room temperature. After TLC indicated the reaction was finished, the mixture was concentrated to remove the solvent. To the residue was added EtOAc (5OmL), and the mixture was neutralized with saturated NaHCO3 to pH 8~9, and then extracted with EtOAc. The combined organic phases were dried with Na2SO4, filtered, concentrated to give a crude (S)-2-(6-chloro-5-fluoro-1H-indol-3-yl)-l- methyl-ethylamine which was used without further purification.

Step 8: To a solution of (5)-2-(6-chloro-5-fluoro-1H-indol-3-yl)-l-methyl-ethylamine (120 mg, 0.5 mmol) in EtOH (1OmL) was added 5-chloroisatin (90 mg, 0.5 mmol) and p-TsOΗ (8 mg, 0.04 mmol). The mixture was heated in a sealed tube at 1100C for 16 hours. After TLC indicated the reaction was finished, the mixture was cooled and concentrated. The residue was dissolved in EtOAc (2OmL) and washed with NaOH (IN) and brine, dried with Na2SO4, filtered, concentrated and the residue was purified with chromatography (petroleum ether/EtOAc 5:1) to give 36 (150mg, 64% yield over two steps).

 

Example 48 (15,3R)-5′-Chloro-3-methyl-2,3,4,9-tetrahydrospiro[β-carboline-l,3′-indol]-2′(l’JH)-one

(35)

35

Compound 35 may be prepared according to Scheme F using the same or analogous synthetic techniques and/or substituting with alternative reagents.

(lS^RVS’-Chloro-S-methyl-l^^^-tetrahydrospirotβ-carboline-l.S’-indoll-l^l’ZO-one: 1H NMR (300 MHz, DMSO-^6): δ 10.45 (s, IH), 10.42 (s, IH), 7.43 (d, J= 7.5 Hz, IH), 7.31 (dd, J = 2.1, 8.4 Hz, IH), 7.16 (d, J = 7.2 Hz, IH), 7.05-7.02 (m, 2H), 7.00-6.96 (m, IH), 6.92 (d, J = 8.1 Hz, IH), 3.98-3.86 (m, IH), 2.78 (dd, J= 3.6, 14.9 Hz, IH), 2.41 (dd, J= 4.5, 25.5 Hz, IH), 1.18 (d, J= 6.3 Hz, 3H); MS (ESI) m/z 338.0 (M+H)+.

Chiral compounds such as 36 and 37 can be prepared according to Scheme G or H using the same or analogous synthetic techniques and/or substituting with alternative reagents. Example 49

(IR^^-S’.T-Dichloro-ό-fluoro-S-methyl-l^^^-tetrahydrospiroIβ-carboline-l^’-indol]- 2\VH)-one (36)

36

35: 1H NMR (500 MHz, DMSO-Jd) δ 10.69 (s, IH), 10.51 (s, IH), 7.43 (d, J = 10.0 Hz, IH), 7.33 (dd, J= 8.4, 2.2 Hz, IH), 7.27 (d, J= 6.5 Hz, IH), 7.05 (d, J= 2.3, IH), 6.93 (d, J= 8.5 Hz, IH), 3.91 (m, IH), 3.13 (bd, J= 6.2 Hz, IH), 2.74 (dd, J= 15.0 , 3.0 Hz, IH), 2.35 (dd, J= 15.0, 10.3, IH), 1.15 (d, J= 6.0, 3H);

MS (ESI) m/z 392.0 (M+2H)+;

[α]25 D = + 255.4°

Example 50

(lS,3R)-5′,7-Dichloro-6-fluoro-3-methyI-2,3,4,9-tetrahydrospiro[β-carboline-l,3′-indol]- 2′(l’H)-one (37)

37

(lS^^-S’^-Dichloro-o-fluoro-S-methyl^jS^^-tetrahydrospirojP-carboline-l-S’-indol]- 2′(l’H)-one: 1H NMR (500 MHz, CDCl3) δ 8.49 (s, IH), 7.54 (s, IH), 7.24 (d, J= 9.7 Hz, IH), 7.21 (dd, J = 8.6, 2.0 Hz, IH), 7.14 (d, J= 6.0 Hz, IH), 7.11 (d, J= 1.8, IH), 6.77 (d, J= 8.3 Hz, IH), 4.14 (m, IH), 2.89 (dd, J = 15.4, 3.7 Hz, IH), 2.49 (dd, J = 15.3, 10.5, IH), 1.68 (bs, IH), 1.29 (d, J= 6.4 Hz, 3H); MS (ESI) m/z 392.0 (M+2H)+; [α]25D -223.3°

PATENT

US 2011275613

http://www.google.com/patents/WO2013139987A1?cl=en

 

Prior art:

(1 ‘R, 3’S)-5, 7′-dichloro-6′-fIuoro-3′-methyl-2′, 3′,4′, 9’-tetrahydrospiro[indoline-3, 1 – pyrido[3,4-b]indol]-2-one (eg. a compound of formula (IV), which comprises a spiroindolone moiety) and a 6-steps synthetic method for preparing, including known chiral amine intermediate compound (MA) are known (WO 2009/132921 ):

he present invention relates to processes for the preparation of spiroindolone compounds, such as (1’R,3’S)-5, 7′-dichloro-6′-fIuoro-3′-methyl-2′,3′,4′,9′- tetrahydrospiro[indoline-3, 1 ‘-pyhdo[3.4-b]indol]-2-one.

(1 ‘R, 3’S)-5, 7′-dichloro-6′-fluoro-3′-methyl-2′, 3′,4 9’-tetrahydrospiro[indoline-3, 1 ‘- pyrido[3, 4-b]indol]-2-one is useful in the treatment and/or prevention of infections such as those caused by Plasmodium falciparum, Plasmodium vivax, Plasmodium malariae, Plasmodium ovale, Trypanosoma cruzi and parasites of the Leishmania genus such as, for example, Leishmania donovani., and it has the following structure:

(IVA)

(1 ‘R, 3’S)-5, 7′-dichloro-6′-fluoro-3′-methyl-2 3′, 4′, 9’-tetrahydrospiro[indoline-3, 1 – pyhdo[3, 4-b]indol]-2-one and a synthesis thereof are described in WO 2009/132921 Al in particular in Example 49 therein.

 

Example 10: Process for Conversion of Compound (IA) to Compound (IIA) in 30g Scale

458.97

152.48g /so-propylamine hydrochloride and 0.204g pyridoxalphosphate monohydrate were dissolved in 495ml water while stirring. To this yellow clear solution a solution of 30. Og ketone in 85ml poly ethylene glycol (average mol weight 200) within 15 minutes. Upon addition the ketone precipitates as fine particles which are evenly distributed in the reaction media. To the suspension 180ml triethanolamine buffer (0.1 mol/l, pH 7) were added and the pH was adjusted to 7 by additon of aqueous sodium hydroxide solution (1 mol/l). The reaction mixture is heated to 50°C and a solution of 1.62g transaminase SEQ ID NO: 134 dissolved in 162ml triethanolamine buffer (0 1 mol/l, pH 7) is added. The reaction mixture is continiously kept at pH 7 by addition of 1 mol/l aqueous sodium hydroxide solution. The reaction mixture is stirred 24h at 50°C and a stream of Nitrogen is blown over the surface of the reaction mixture to strip off formed acetone. The reaction mixture is then cooled to 25°C and filtered over a bed of cellulose flock. The pH of the filtrate is adjusted to «1 by addition of concentrated sulfuric acid. The acidified filtrated is extracted with 250 ml /so-Propyl acetate. The layers are separated and the pH of the aqueous phase is adjusted to ¾10 by additon of concentrated aqueous sodium hydroxide solution. The basified aqueous phase is extracted with /so-propyl acetate. The layers are seperated and the organic phase is washed with 100 ml water. The organic phase is concentrated by distillation to 2/3 of its origin volume. In a second reactor 33.98g (+)- camphor sulfonic acid is dissolved in 225 ml /so-propyl acetate upon refluxing and the concentrated organic phase is added within 10 minutes. After complete addition the formed thin suspension is cooled to 0°C within 2 hours and kept at 0°C for 15 hours. The precipitated amine-(+)-camphor sulfonate salt is filtered, washed with 70 ml /so-propyl acetate and dried at 40°C in vaccuum yielding 51.57g of colourless crystals (84.5% yield t.q.)

Analytical Data

IR:

v (crn 1)=3296, 3061 , 2962, 2635, 2531 , 2078, 1741 , 1625, 1577, 1518, 1461 , 1415, 1392, 1375, 1324, 1302, 1280, 1256, 1226, 1 170, 1 126, 1096, 1041 , 988, 966, 937, 868, 834, 814, 790, 766, 746, 719, 669, 615.

LC-MS (ESI +):

Ammonium ion: m/z =227 ([M+H]), 268 ([M+H+CH3CN]), 453 ([2M+H]).

Camphorsulfonate ion: m/z =250 ([M+NH4]), 482 ([2M+NH4]).

LC-MS (ESI -):

Camphorsulfonate ion: m/z=231 ([M-H]), 463 ([2M-H]).

1H-NMR (DMSO-d6, 400 MHz):

1 1.22 (br. s., 1 H), 7.75 (br. s., 3H), 7.59 (d, J = 10.3 Hz, 1 H), 7.54 (d, J = 6.5 Hz, 1 H), 7.36 (d, J = 2.3 Hz, 1 H), 3.37 – 3.50 (m, 1 H), 2.98 (dd, J = 14.3, 5.8 Hz, 1 H), 2.91 (d, J = 14.8 Hz, 1 H), 2,81 (dd, J = 14.3, 8.0 Hz, 1 H), 2.63 – 2.74 (m, 1 H), 2.41 (d, J = 14.6 Hz, 1 H), 2.24 (dt, J = 18.3, 3.8 Hz, 1 H), 1 .94 (t, J = 4.4 Hz, 1 H), 1.86 (dt, J = 7.4, 3 6 Hz, 1 H), 1.80 (d, J = 18.1 Hz, H), 1.23 – 1 .35 (m, 2H), 1.15 (d, J = 6.3 Hz, 3H), 1.05 (s, 3H), 0.74 (s, 3H)

Free Amine (obtained by evaporatig the iso-Propylacetate layer after extraction of the basified aqueous layer):

1H NMR (400MHz, DMSO-d6): 11 .04 (br. s., 1 H), 7.50 (d, J = 10.5 Hz, 1 H), 7.48 (d, J = 6.5 Hz, 1 H), 7.25 (s, 1 H), 3.03 (sxt, J = 6.3 Hz, 1 H), 2.61 (dd, J – 14.3, 6.5 Hz, 1 H), 2.57 (dd, J = 14.1 , 6.5 Hz, 1 H), 1.36 (br. s., 2H), 0.96 (d, J = 6.3 Hz, 3H)

Example 11: Process for Conversion of Compound (HA) to Compound (IVB)

3. solvent exchange to TP

13.62 g 5-chloroisatin is suspended in 35 ml /so-propanol and 2.3 g triethyl amine is added. The suspension is heated to reflux and a solution of 34.42g amine-(+)-camphor sulfonate salt dissolved in 300 ml /so-propanol is added within 50 minutes. The reaction mixture is stirred at reflux for 17 hours. The reaction mixture is cooled to 75°C and 17.4g (+)-camphorsulfonic acid are added to the reaction mixture. Approximately 300 ml /so- propanol are removed by vacuum distillation. Distilled off /so-propanol is replaced by iso- propyl acetate and vacuum distillation is continued. This is distillation is repeated a second time. To the distillation residue 19 ml ethanol and 265 ml ethyl acetate is added and the mixture is heated to reflux. The mixture is cooled in ramps to 0°C and kept at 0°C for 24 hours. The beige to off white crystals are filtered off, washed with 3 portions (each 25 ml) precooled (0°C) ethylacetate and dried in vacuum yielding 40.3 g beige to off white crystals. (86.3% yield t.q.)

IR:

v (crrr)= 3229, 3115, 3078, 3052, 2971 , 2890, 2841. 2772. 2722, 2675, 2605, 2434. 1741 , 1718, 1621 , 1606, 1483, 1460, 1408, 1391 , 1372, 1336, 1307, 1277, 1267, 1238, 1202, 1 184, 1 162, 1 149, 1 128, 1067, 1036, 987, 973, 939, 919, 896, 871 , 857, 843, 785, 771 , 756, 717, 690, 678, 613.

LC-MS (ESI +):

Ammonium ion: m/z =390 ([M+H]), 431 ([M+H+CH3CN]) Camphorsulfonate ion: m/z =250 ([M+NH4]), 482 ([2M+NH4])

LC-MS (ESI -):

Camphorsulfonate ion: m/z=231 ([M-H]), 463 ([2M-H])

1H NMR (DMSO-d6, 600 MHz):

11.49 (s, 1 H), 1 1.23 (s, 1 H), 10.29 – 10.83 (m, 1 H), 9.78 – 10.31 (m, 1 H), 7.55 – 7.60 (m, 2H), 7.52 (s, 1 H), 7.40 (d, J = 6.2 Hz, H), 7.16 (d, J = 8.8 Hz, 1 H), 4.52 – 4.63 (m, 1 H). 3.20 (dd, J = 16.3, 4.2 Hz, 1 H), 2.96 (dd, J = 16.1 , 11.3 Hz, 1 H), 2.90 (d, J = 15.0 Hz, 1 H), 2.56 – 2.63 (m, 1 H), 2.39 (d, J = 14.6 Hz, 1 H), 2.21 (dt, J = 18.0, 3.8 Hz, 1 H), 1.89 – 1.93 (m, 1 H), 1.81 (ddd, J = 15.3, 7.8, 3.7 Hz, 1 H), 1.76 (d, J = 18.3 Hz, 1 H), 1 .53 (d, J = 6.6 Hz, 3H), 1.20 – 1.33 (m, 2H), 0.98 (s, 3H), 0.70 (s, 3H)

Example 12: Process for Preparing a Compound of formula (IVA) 1/z Hydrate

mw622.54 …………………………………………………………………..mw399.25

In a 750ml reactor with impeller stirrer 50g of compound (IVB) salt were dissolved in 300ml Ethanol (ALABD) and 100 ml deionised Water (WEM). The clear, yellowish sollution was heated to 58°C internal temperature. To the solution 85 g of a 10% aqueous sodium carbonate solution was added within 10 minutes. The clear solution was particle filtered into a second reaction vessel. Vessel and particle filter were each rinsed with 25 ml of a mixture of ethanohwater (3:1 v/v) in the second reaction vessel. The combined particle filtered solution is heated to 58°C internal temperature and 200ml water (WEM) were added dropwise within 15 minutes. Towards the end of the addition the solution gets turbid.

The mixture is stirred for 10 minutes at 58°C internal temperature and is then cooled slowely to room temperature within 4hours 30 minutes forming a thick, well stirable white suspension. To the suspension 200 ml water are added and the mixture is stirred for additional 15hours 20 minutes at room temperature. The suspension is filtered and the filter cake is washed twice with 25 ml portions of a mixture of ethanohwater 9: 1 (v/v). The colourless crystals are dried at 60°C in vacuum yielding 26.23g (=91.2% yield). H NMR (400 MHz, DMSO-d6)

0.70 (s, 1H), 10.52 (s, 1H), 7.44 (d, J = 10.0 Hz, 1H), 7.33 (dd, J = 8.4, 2.1 Hz, 1H),.26 (d, J = 6.5 Hz, 1H), 7.05 (d, J = 2.3 Hz, 1H), 6.93 (d, J = 8.3 Hz, 1H), 3.83 – 4.00 (m,H), 3.13 (d, J = 6.0 Hz, 1H), 2.77 (dd, J = 15.1, 3.8 Hz, 1H), 2.38 (dd, J = 15.1, 10.5 Hz,H), 1.17 (d, J = 6.3 Hz, 3H).

 

PAPER
 Journal of Medicinal Chemistry, 2010 ,  vol. 53,   14  p. 5155 – 5164

(1R,3S)-5′,7-Dichloro-6-fluoro-3-methyl-2,3,4,9-tetrahydrospiro[β-carboline-1,3′-indol]-2′(1′H)-one (19a)

1H NMR (500 MHz, DMSO-d6): δ 10.69 (s, 1H), 10.51 (s, 1H), 7.43 (d, J = 10.0 Hz, 1H), 7.33 (dd, J = 8.0, 2.2 Hz, 1H), 7.27 (d, J = 6.5 Hz, 1H), 7.05 (d, J = 2.3 Hz, 1H), 6.93 (d, J = 8.5 Hz, 1H), 3.91 (m, 1H), 3.13 (bd, J = 6.2 Hz, 1H), 2.74 (dd, J = 15.0, 3.0 Hz, 1H), 2.35 (dd, J = 15.0, 10.3 Hz, 1H), 1.15 (d, J = 6.0 Hz, 3H). MS (ESI) m/z 392.0 (M + 2H)+; [α]D25 = +255.4° (c = 0.102 g/L, methanol).
CLIPS

Z.Zhang, WO 2007 / 104714,2007).

 

Figure CN102432526AD00051

[0008] (2) year 2008 Roche pharmaceutical company disclosed a spiro [oxindole – cyclohexenone] skeleton biomedicine, PCT International Application No. W02008 / 055812. It also announced the preparation of anti-cancer agents and antagonists of the application of the compound is used as the interaction with MDM2 (reference:. Liu, J.-J; Zhang, Z; (Hoffmann-LaRoche AG), PCT Int App 1. . W02008 / 055812, 2008), its structural formula is as follows:

[0009]

Figure CN102432526AD00052

(3) Melchiorre research group abroad chiral amines and o-fluoro-3-benzyl benzoate as catalyst methylene-indole-2-one (3-benzylideneindolin-2-one, CAS Number: 3359-49- 7) with α, β – unsaturated ketone synthesis of chiral spiro [cyclohexane _1,3′- indole] _2,4 ‘- dione [s pir0 [cycl0hexane-l, 3’ -indoline] – 2 ‘, 4-diones] compounds (see:.. Bencivenni, G; ffu, LY; Mazzanti, A .; Giannichi, B.; Pesciaioli, F; Song, Μ P.; Bartoli, G.; Melchiorre, P …. .Angew Chem Int Ed 2009,48,7200), the structure of the total formula is as follows:

 

Figure CN102432526AD00061

(4) Gong Flow column team found to cyclohexanediamine derived Bronsted acid – a bifunctional catalyst Lewis base catalysis of 3-benzyl-methylene-indole-2-one and α, β- unsaturated 1,3 tandem reaction dicarbonyl compound (Nazarov reagent) can be obtained with high stereoselectivity chiral spiro [cyclohexane _1,3′- indol] -2 ‘, 4-dione [spiro [cyclohexane-l, 3 ‘-indoline] -2’, 4-diones] compounds; and by this method successfully synthesized 7 Roche pharmaceutical companies to develop chiral anti-tumor agents (see: Q Wei, L -Z Gong, Org Lett 2010….. , 12, 1008.).

(5) Wang Lixin research group recently reported that primary amines derived from cinchona alkaloids and Bronsted acid as catalyst N- protected indolone compounds and double Michael addition reaction of diketene generate hand spiro [cyclohexane-1, 3′-indol] -2 ‘, 4-dione [spiro [cyclohexane-l, 3’ -indoline] -2 ‘, 4-diones] type of tx ^ (: L. -L. Wang, L. Peng, J. -F. Bai, L. -N. Jia, X. -Y. Luo, QC Huang, L. -X. Wang, Chem. Commum. 2011,47, 5593.).

WO2009132921A1 * Apr 1, 2009 Nov 5, 2009 Novartis Ag Spiro-indole derivatives for the treatment of parasitic diseases
WO2010081053A2 * Jan 8, 2010 Jul 15, 2010 Codexis, Inc. Transaminase polypeptides
WO2012007548A1 * Jul 14, 2011 Jan 19, 2012 Dsm Ip Assets B.V. (r)-selective amination
AT507050A1 * Title not available
EP0036741A2 * Mar 17, 1981 Sep 30, 1981 THE PROCTER &amp; GAMBLE COMPANY Phosphine compounds, transition metal complexes thereof and use thereof as chiral hydrogenation catalysts
EP0120208A2 * Jan 24, 1984 Oct 3, 1984 Degussa Aktiengesellschaft Microbiologically produced L-phenylalanin-dehydrogenase, process for obtaining it and its use
EP0135846A2 * Aug 31, 1984 Apr 3, 1985 Genetics Institute, Inc. Production of L-amino acids by transamination
GB974895A * Title not available
US3282959 * Mar 21, 1962 Nov 1, 1966 Parke Davis & Co 7-chloro-alpha-methyltryptamine derivatives
US4073795 * Jun 22, 1976 Feb 14, 1978 Hoffmann-La Roche Inc. Synthesis of tryptophans
WO2005009370A2 * Jul 22, 2004 Feb 3, 2005 Pharmacia Corp Beta-carboline compounds and analogues thereof and their use as mitogen-activated protein kinase-activated protein kinase-2 inhibitors
EP0466548A1 * Jun 27, 1991 Jan 15, 1992 Adir Et Compagnie 1,2,3,4,5,6-Hexahydroazepino[4,5-b]indole and 1,2,3,4-tetrahydro-beta-carbolines, processes for their preparation, and pharmaceutical compositions containing them

Рисунок из Science 2010, 329, 1175

Исследовательская группа Элизабет Винцелер (Elizabeth A. Winzeler) разработала новый препарат, первоначально проведя скрининг библиотеки, состоящей из 12000 соединений, а затем получив производные наиболее перспективных кандидатов. В результате долгой работы исследователи отобрали единственное соединение спироиндолоновой структуры, получившее регистрационный номер NITD609. В случае успешного прохождения экспертизы фармакологических и токсикологических свойств нового соединения исследователи надеются приступить к первой фазе его клинических испытаний уже в конце этого года.

Было обнаружено, что NITD609 быстро останавливает белковый синтез в организме возбудителя малярии, ингибируя ген аденозинтрифосфатазы, ответственной за транспорт катионов через мембрану клетки возбудителя. То, что механизм действия нового соединения отличается от механизма, характерного для других средств лечения малярии, объясняет причины успешного действия нового препарата в том числе и против штаммов малярии, выработавших резистентность.

 HPLC
Analyte quantization was performed byLC/MS/MS. Liquid chromatography was performed using an Agilent
1100 HPLC system(Santa Clara, CA), with the Agilent Zorbax XDB Phenyl (3.5μ, 4.6 x75 mm) column at
an oven temperature of 35 °C, coupled with a QTRAP4000 triple quadruple mass
spectrometer (Applied Biosystems, Foster City, CA). Instrumentcontrol and dataacquisition were performed using Applied Biosystems software Analyst 1.4.2. Themobile phases used were A: water:acetic acid (99.8:0.2, v/v) and B: acetonitrile:aceticacid (99.8:0.2, v/v), using a gradient, with flow rate of 1.0 mL/min, and run time of 5minutes. Under these conditions the retention time of9a
was 3.2 minutes. Compounddetection on the mass spectrometer was performed in electrospraypositive ionizationmode and utilized multiple reaction monitoring (MRM) for specificity (9atransitions338.3/295.1, 338.3/259.2) together with their optimized MS parameters. The lower limitof quantification for9awas 70 ng/mL.
Extraction and LCMS analysis of 20a.Plasma samples were extracted withacetonitrile:methanol-acetic acid (90:9.8:0.2 v/v) for the analyte and internal standard(17a) using a 3.6 to 1 extractant to plasma ratio. Analyte quantitation was performed by
LC/MS/MS. Liquid chromatography was performed using an Agilent1100 HPLC systemS7(Santa Clara, CA), with the Agilent Zorbax XDB-Phenyl (3.5μ, 4.6x75mm) column atan oven temperature of 45 °C coupled with a QTRAP 4000 triple quadruple massSpectrometer (Applied Biosystems, Foster City, CA). Instrumentcontrol and dataacquisition were performed using Applied Biosystems software Analyst 1.4.2. Themobile phases used were A: water:acetic acid (99.8:0.2, v/v) and B: methanol:acetic acid
(99.8:0.2, v/v), using gradient elution conditions with a flow rate of 1.0 mL/min and a runtime of 6 minutes
++++++++++++++++++++++==

+++++++++++++++++++++++++++=

References

  1.  “NITD 609”. Medicines for Malaria Venture.
  2.  Rottmann M, McNamara C, Yeung BK, Lee MC, Zou B, Russell B, Seitz P, Plouffe DM, Dharia NV, Tan J, Cohen SB, Spencer KR, González-Páez GE, Lakshminarayana SB, Goh A, Suwanarusk R, Jegla T, Schmitt EK, Beck HP, Brun R, Nosten F, Renia L, Dartois V, Keller TH, Fidock DA, Winzeler EA, Diagana TT (2010). “Spiroindolones, a potent compound class for the treatment of malaria”. Science329 (5996): 1175–80. doi:10.1126/science.1193225. PMC 3050001. PMID 20813948.

Ang, S. H., Krastel, P., Leong, S. Y., Tan, L. J., Wong, W. L. J., Yeung, B. K., and Zou, B. Spiro-indole derivatives for the treatment of parasitic diseases. WO2009132921 A1, November 5, 2009.

Cipargamin
NITD609.svg
Names
IUPAC name

(1R,3S)-5’,7-Dichloro-6-fluoro-3-methyl-spiro[2,3,4,9-tetrahydropyrido[3,4-b]indole-1,3’-indoline]-2’-one
Identifiers
1193314-23-6
ChemSpider 24662493
Jmol interactive 3D Image
PubChem 44469321
Properties
C19H14Cl2FN3O
Molar mass 390.24 g·mol−1

SEE……….http://apisynthesisint.blogspot.in/2016/02/kae-609-nitd-609-cipargamin-for-malaria.html

////

C[C@H]1Cc2c3cc(c(cc3[nH]c2[C@]4(N1)c5cc(ccc5NC4=O)Cl)Cl)F

Artesunate, the antimalarial


Artesunate.svg

ARTESUNATE
Butanedioic acid mono[(3R,5aS,6R,8aS,9R,10R,12R,12aR)-decahydro-3,6,9-trimethyl-3,12-epoxy-12H-pyrano[4,3-j]-1,2-benzodioxepin-10-yl] ester
(3R,5aS,6R,8aS,9R,10S,12R,12aR)-Decahydro-3,6,9-trimethyl-3,12-epoxy-12H-pyrano(4,3-j)-1,2-benzodioxepin-10-ol, hydrogen succinate
Butanedioic acid, mono((3R,5aS,6R,8aS,9R,10S,12R,12aR)-decahydro-3,6,9-trimethyl-3,12-epoxy-12H-pyrano(4,3-j)-1,2-benzodioxepin-10-yl) ester
Additional Names: artesunic acid; dihydroqinghaosu hemisuccinate, Succinic ester of artemether.
Molecular Formula: C19H28O8
Molecular Weight: 384.42
Percent Composition: C 59.36%, H 7.34%, O 33.30%
Artesunate (superseded RN); Dihydroartemisinine-12-alpha-succinate; Succinyl dihydroartemisinin; Quinghaosu reduced succinate ester
Therap-Cat: Antimalarial.

Artesunate (INN) is part of the artemisinin group of drugs that treat malaria. It is a semi-synthetic derivative of artemisinin that is water-soluble and may therefore be given by injection. It is sometimes abbreviated AS.

It is on the World Health Organization’s List of Essential Medicines, a list of the most important medication needed in a basic health system.[1]

Artesunate

  • Arinate
  • Armax 200
  • Arsuamoon
  • Arsumax
  • Artesunata
  • Artesunate
  • Artesunato
  • Artesunato [INN-Spanish]
  • Artesunatum
  • Artesunatum [INN-Latin]
  • Artesunic acid
  • Asumax
  • Cosinate
  • Dihydroqinghasu hemsuccinate
  • Gsunate Forte
  • HSDB 7458
  • Plasmotrin
  • Qinghaozhi
  • Quinghaosu reduced succinate ester
  • Saphnate
  • SM 804
  • Succinyl dihydroartemisinin
  • UNII-60W3249T9M
  • WR 256283
  • Zysunate
SODIUM ARTESUNATE Structure
SODIUM ARTESUNATE;
Dihydroartemisinin alpha-hemisuccinate sodium salt;
Sodium dihydroarteannuin hydrogen succinate monoester;
Butanedioic acid 1-[(3R,5aα,8aα,12aR)-decahydro-3,6α,9β-trimethyl-3β,12α-epoxypyrano[4,3-j]-1,2-benzodioxepin-10α-yl]4-sodium salt;
Butanedioic acid, mono(decahydro-3,6,9-trimethyl-3,12-epoxy-12H-pyrano(4,3-J)-1,2-benzodioxepin-10-yl)ester, sodium salt, (3R-(3-alpha,5A-beta,6-beta,8A-beta,9-alpha,10-alpha,12-beta,12ar*))-
CAS 82864-68-4
Derivative Type: Sodium salt
Manufacturers’ Codes: SM-804
Molecular Formula: C19H27NaO8
Molecular Weight: 406.40
Percent Composition: C 56.15%, H 6.70%, Na 5.66%, O 31.49%
Properties: Poor stability in aqueous solutions. LD50 in mice (mg/kg): 520 i.v.; 475 i.m. (China Cooperative Research Group); also reported as 699 ± 58.5 i.v. (Zhao, 1985).
Toxicity data: LD50 in mice (mg/kg): 520 i.v.; 475 i.m. (China Cooperative Research Group); also reported as 699 ± 58.5 i.v. (Zhao, 1985)

Medical uses

The World Health Organization recommends intramuscular or intravenous artesunate as the first line treatment for severe malaria.[2]Artesunate was shown to prevent more deaths from severe malaria than quinine in two large multicentre randomized controlled trials from Africa[3] and Asia.[4] A subsequent systematic review of seven randomized controlled trials found this beneficial effect to be consistent across all trials.[5]

For severe malaria during pregnancy, there is less certainty about the safety of artesunate during the first trimester but artesunate is recommended as first-line therapy during the second and third trimesters.[6]

Artesunate is also used to treat less severe forms of malaria when it can be given orally, but should always be taken with a second antimalarial such as mefloquine or amodiaquine to avoid the development of resistance.[2]

While artesunate is used primarily as treatment for malaria, there is some evidence that it may also have some beneficial effects inSchistosoma haematobium infection,[7] but this needs confirming in large randomized trials.

Adverse effects

Artesunate is generally safe and well-tolerated. The best recognised side effect of the artemesinins that they lower reticulocyte counts.[8] This is not usually of clinical relevance.

Delayed haemolysis (occurring around two weeks after treatment) has been observed in patients treated with artesunate for severe malaria.[9] Whether or not this haemolysis is due to artesunate, or to the malaria itself is unclear.[10]

The safety of artesunate in pregnancy is unclear. There is evidence of embryotoxicity in animal models (defects in long bones and ventricular septal defects in the heart in rates and monkeys). However, observational evidence from 123 human first-trimester pregnancies showed no evidence of damage to the fetus.[11]

Synthesis

Artesunate is prepared from dihydroartemisinin (DHA) by reacting it with succinic acid anhydride in basic medium. Pyridine as base/solvent, sodium bicarbonate in chloroform and catalyst DMAP (N,N-dimethylaminopyridine) and triethylamine in 1,2-dichloroethane have been used, with yields of up to 100%. A large scale process involves treatment of DHA indichloromethane with a mixture of pyridine, a catalytic amount of DMAP and succinic anhydride. The dichloromethane mixture is stirred for 6–9 h to get artesunate in quantitative yield. The product is further re-crystallized from dichloromethane. alpha-Artesunate is exclusively formed (m.p 135–137˚C).

Artemisinin and its ether and ester derivatives show antimalarial activity against multidrug resistant strains. Ether derivatives like arteether and artemether shows better activity but they suffer from some limitation like solubility, short half life. Unlike ether derivatives, ester derivatives like artesunate has increased solubility and improved pharmacokinetic properties. The water insoluble dihydroartimisinin hemisuccinate is given orally in tablet form and water soluble artesunate sodium is given as LV.

Artesunate was first prepared by Chinese scientists, using different methods. One of them describes acylation of dihydroartemisinin by succinic anhydride in pyridine at 300C for 24 hr with yield of 60%. In another method, described in Acta. Chim. Sinica 40(6), 557-561., ester derivatives of dihydroartemisinin was prepared in presence of 4- (N, N-dimethylamino) pyridine and triethylamine as basic catalyst and 1 ,2 dichloroethane as solvent. The reaction is continued until complete conversion of dihydroartemisinin and product is isolated and purified by silica gel column giving overall yield 60-90%.

Another improved method disclosed in US patent 5654446, describes preparation of artesunate from dihydroartemisinin and succinic anhydride in presence of triethylamine as basic catalyst and in low boiling water miscible dry solvent like acetone. After completion of reaction, mixture is acidified and diluted with water to get artesunate. The yield of esterification is 96%.

U.S. patent 6677463 discloses one pot method for preparation of artesunate from artemisinin. Method describes reduction of artermisinin to dihydroartemisinin in presence of polyhydroxy compound and sodium borohydride. After completion of reaction succinic anhydride and anion exchange resin was added to reaction mass and stirred for 2 hrs. Then cold water was added and product was extracted with ethylacetate hexane mixture in pH range of 6-7. Distilling off the solvent yields the crude artesunate which on silica gel column purification gives 96 % of pure artesunate. The process is complex and time consuming as it involves chromatographic purification step.

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Chemical structure for artesunate

http://www.google.com/patents/WO2008087667A1?cl=en

Example 1 discloses the process for obtaining artesunate. The process involves reducing artemisinin to dihydroartemisinin in presence of 1, 2-propanediol and sodium borohydride in a solvent mixture of hexane and isopropanol to give dihydroartemisinin in a yield of 92%. The ratio of artemisinin to 1 , 2-propanediol is 1 :0.66 w/w and the ratio of artemisinin to sodium borohydride is 1 :0.33 w/w. The high yield is attributed to the combination of 1 , 2-propanediol and sodium borohydride in a solvent mixture of hexane and isopropanol that could not be derived from prior art. The dihydroartemisinin is esterified using succinic anhydride and imidazole to give the artesunate in a yield of 100% in 40 min. The ratio of artemisinin to succinic anhydride is 1 :0.52 w/w and that of artemisinin to imidazole is 1 :0.2 w/w. Further, high yield of artesunate obtained in less time was due to imidazole catalyst that accelerates the rate of reaction. Moreover, the process of the present disclosure does not employ purification over silica gel as is in the prior art, but the pure compound is obtained by simple crystallization using suitable solvent.

Example 2 describes the process for obtaining artesunate. The process involves reducing artemisinin to dihydroartemisinin as in example 1. The dihydroartemisinin is esterified using succinic anhydride and imidazole to give the artesunate in a yield of

100% in 25 min. The ratio of artemisinin to succinic anhydride is 1 :0.52 w/w and that of artemisinin to imidazole is 1 :0.3 w/w.

Example 3 describes the process for obtaining artesunate involving reducing artemisinin to dihydroartemisinin in presence of 1, 2-propanediol and sodium borohydride in a solvent mixture of hexane and isopropanol to give dihydroartemisinin in a yield of 88% in 40 min. The ratio of artemisinin to 1, 2-propanediol is 1 :0.8 w/w and the ratio of artemisinin to sodium borohydride is 1 :0.4 w/w. The dihydroartemisinin is esterified using succinic anhydride and imidazole to give the artesunate in a yield of 86%. The ratio of artemisinin to succinic anhydride is 1 :0.52 w/w and that of artemisinin to imidazole is 1 :0.2 w/w.

Example 4 describes the process for obtaining artesunate involving reducing artemisinin to dihydroartemisinin as in example 1. The dihydroartemisinin is esterified using succinic anhydride and imidazole to give the artesunate in a yield of 90% in 210 min. The ratio of artemisinin to succinic anhydride is 1 :0.52 w/w and that of artemisinin to imidazole is 1 :0.1 w/w.

Example 5 describes the process for obtaining artesunate involving reducing artemisinin to dihydroartemisinin as in example 1. The dihydroartemisinin is esterified using succinic anhydride and imidazole in dichloromethane to give the artesunate in a yield of 92% in 60 min. The ratio of artemisinin to succinic anhydride is 1:0.44 w/w and the ratio of artemisinin to imidazole is 1 :0.2 w/w.

Example 6 describes the process for obtaining artesunate involving reducing artemisinin to dihydroartemisinin as in example 1. The dihydroartemisinin is esterified using succinic anhydride and imidazole in acetonitrile to give the artesunate in a yield of 92% in 180 min. The ratio of artemisinin to succinic anhydride is 1:0.52 w/w and that of artemisinin to imidazole is 1 :0.2 w/w.

Example 1 Artemisinin (1.0 g) and 1, 2-propanediol (0.66 g) was added to a mixture of isopropanol (3.5 ml) and hexane (10 ml) and the suspension was stirred for 2 minutes at 2O0C followed by the addition of Sodium borohydride (0.33 gm). After 2 minutes of stirring, dihydroartemisinin started precipitating and the reaction mixture was further stirred for about 8 minutes at 2O0C. Water (10 ml) was added to the reaction mixture and stirred for 10 minutes at 100C. Solid was filtered, washed with hexane (2 * 20 ml) and dried to yield 0.92 g (92% w/w) dihydroartemisinin.

Dihydroartemisinin (0.92 g) was stirred in dichloromethane (10 ml) for 2 minutes at room temperature. Succinic anhydride (0.52 g) and imidazole (0.2 g) were added to this solution and stirred for 40 minutes. The pH of reaction mixture was adjusted to 5-6 and organic layer was washed with water, dried and concentrated to oily mass. The oily mass was dissolved in methanol (1.5 ml) and stirred for 2 min to obtain a clear solution. Water (ImI) was added dropwise to this solution to start the precipitation of artesunate and the suspension was stirred for 5 minutes. The solid was filtered, washed with cold water (2 x 2ml) and dried to yield 1.0 g of artesunate. The overall yield of artesunate was 100 % w/w.

Example 2

Reduction of artemisinin to dihydroartemisinin was carried out as described in Example 1. Dihydroartemisinin (0.92 g) was stirred in dichloromethane (10 ml) for 2 minutes at room temperature. Succinic anhydride (0.52 g) and imidazole (0.3 g) were added to this solution and stirred for 25 minutes. The pH of reaction mixture was adjusted to 5-6 and organic layer was washed with water, dried and concentrated to oily mass. The oily mass was dissolved in methanol (1.5 ml) and stirred for 2 min to obtain a clear solution. Water (ImI) was added dropwise to this solution to start the precipitation of artesunate and the suspension was stirred for 5 minutes. The solid was filtered, washed with cold water (2 χ 2 ml) and dried to yield 1.0 g of artesunate. The overall yield of artesunate was 100 % w/w.

Example 3

Artemisinin (1.0 g) and 1, 2-propanediol (0.8 g) was added to a mixture of isopropanol (3.5 ml) and hexane (10 ml) and the suspension was stirred for 2 minutes at 2O0C followed by the addition of Sodium borohydride (0.4 g). After 2 minutes of stirring, dihydroartemisinin started precipitating and the reaction mixture was further stirred for about 8 minutes at 200C. Water (7.5 ml) was added to the reaction mixture and stirred for 10 minutes at 100C. Solid was filtered, washed with hexane (2 ^ 2 ml) and dried to yield 0.88 g (88% w/w) dihydroartemisinin.

Dihydroartemisinin (0.88 g) was stirred in dichloromethane (10 ml) for 2 minutes at room temperature. Succinic anhydride (0.52 g) and imidazole (0.2 g) were added to this solution and stirred for 40 minutes. The pH of reaction mixture was adjusted to 5-6 and organic layer was washed with water, dried and concentrated to oily mass. The oily mass was dissolved in methanol (1.5 ml) and stirred for 2 min to obtain a clear solution. Water (ImI) was added dropwise to this solution to start the precipitation of artesunate and the suspension was stirred for 5 minutes. The solid was filtered, washed with cold water (2 x 2ml) and dried to yield 0.86 g of artesunate. The overall yield of artesunate was 86 % w/w.

Example 4

Reduction of artemisinin to dihydroartemisinin was carried out as described in Example 1. Dihydroartemisinin (0.92 g) was stirred in dichloromethane (10 ml) for 2 minutes at room temperature. Succinic anhydride (0.52 g) and imidazole (0.1 g) were added to this solution and stirred for 210 minutes. The pH of reaction mixture was adjusted to 5-6 and organic layer was washed with water, dried and concentrated to oily mass. The oily mass was dissolved in methanol (1.5 ml) and stirred for 2 min to obtain a clear solution. Water (ImI) was added dropwise to this solution to start the precipitation of artesunate and the suspension was stirred for 5 minutes. The solid was filtered, washed with cold water (2 x 2 ml) and dried to yield 0.9 g of artesunate. The overall yield of artesunate was 90 % w/w.

Example 5

Reduction of artemisinin to dihydroartemisinin was carried out as described in Example 1. Dihydroartemisinin (0.92 g) was stirred in dichloromethane (10 ml) for 2 minutes at room temperature. Succinic anhydride (0.44 g) and imidazole (0.2 g) were added to this solution and stirred for 60 minutes. The pH of reaction mixture was adjusted to 5-6 and organic layer was washed with water, dried and concentrated to oily mass. The oily mass was dissolved in methanol (1.5 ml) and stirred for 2 min to obtain a clear solution. Water (ImI) was added dropwise to this solution to start the precipitation of artesunate and the suspension was stirred for 5 minutes. The solid was filtered, washed with cold water (2 x 2 ml) and dried to yield 0.92 g of artesunate. The overall yield of artesunate was 92 % w/w. Example 6

Reduction of artemisinin to dihydroartemisinin was carried out as described in

Example 1. Dihydroartemisinin (0.92 g) was stirred in acetonitrile (10 ml) for 2 minutes at room temperature. Succinic anhydride (0.52 g) and imidazole (0.2gm) were added to this solution and stirred for 180 minutes. The pH of reaction mixture was adjusted to 5-6 and it was extracted with dichloromethane (10 ml). The organic layer was washed with water (20 ml), dried and concentrated to oily mass. The oily mass was dissolved in methanol (1.5 ml) and stirred for 2 min to obtain a clear solution. Water (ImI) was added dropwise to this solution to start the precipitation of artesunate and the suspension was stirred for 5 minutes. The solid was filtered, washed with cold water (2 x 2 ml) and dried to yield 0.92 g of artesunate. The overall yield of artesunate was 92 % w/w.

Mechanisms of action

In a hematin dependent manner, artesunate has been shown to potently inhibit the essential Plasmodium falciparum exported protein 1 (EXP1), a membrane glutathione S-transferase.[12]

Drug resistance

Clinical evidence of drug resistance has appeared in Western Cambodia, where artemisinin monotherapy is common.[13] There are as yet no reports of resistance emerging elsewhere.

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http://www.google.com/patents/WO2004050661A1?cl=en

Malaria is caused by protozoan parasites, notably Plasmodium falciparum. The range of drugs available in the market for prevention and treatment of malaria is limited, and there are problems of drag resistance. Artemisinin and its derivatives: artemether and arteether (oil soluble), artelinate and artesunate (water soluble), are a class of anti-malarial compounds derived from Artemisia annua which are now proving their promising activity and are being used for the treatment of uncomplicated/severe complicated/cerebral and multi drug resistant malaria. The chemistry and the anti-protozoal action of these compounds, described in the publications are listed as references cited.

The water-insoluble artesunic acid is customarily administered orally in the form of tablets or rectally in the form of suppositories, while the water- soluble artesunate is administered intravenously.

Artesunic acid together with a number of other Cio-ester and CiQ-ether” derivatives of dihydroartemisinin, were prepared for the first time by Chinese scientists at the end of 1979 to the beginning of 1980. Shaofeng et al., H Labeling of QHS Derivatives, Bull. Chin. Materia Medica 6 (4), 25-27 (1981) and Li et al, Synthesis of Ethers. Carboxylic esters and carbonates of Dihydroartemisinin, Acta Pharm. Sin 16(6), 429-39, 1981) describe the preparation of artesunic acid by acylation of dihydroartemisinin with succinic anhydride in pyridine. The above mentioned publications describe a general method for preparing various dihydroartemisinin Cι0-esters and also provide a process for preparing artesunic acid in a yield of 60% by means of warming dihydroartemisinin and succinic anhydride in pyridine at 30° C for 24 hours.

Ying et al. in the Synthesis of some carboxylic esters and carbonates of Dihydroartemisinin by using 4-(N, N-Dimethylamino) pyridine as an active acylation catalyst, Acta Chim Sinica 40 (6), 557-561 982) proposed an improved version of the acylation of dihydroartemisinin. The said publication described in detail with the aid of the preparation of dihydroartemisinin – 10-valerate the aforesaid process. In this process dihydroartimisinin was dissolved in 1,2-dichloroethane and treated with valeric anhydride, 4-(N, N-dimethylamino) pyridine and triethylamine, and the mixture was stirred at room temperature until dihydroartemisinin had been used up. The reaction mixture was then acidified with dilute hydrochloric acid and the aqueous phase was separated off. The oily residue, obtained after washing and drying the organic phase and distilling off the solvent, was purified by chromatography on silica gel using petroleum ether 60-80° C degree/ethyl acetate (10:1) as an eluent. The use of this procedure for the preparation of the artesunic acid from dihydroartemisinin with succinic anhydride and 4-(N, N-dimethylamino) pyridine afforded artesunic acid in a yield of 65% in 5 hours.

U.S. Patent No. 5,654,446 granted to Ognyanov et al. titled “Process for preparation of Dihydroartemisinin Hemisuccinate (artesunic acid)”, dated August 5, 1997 teaches a process for preparing o α-artesunic acid by acylation of dihydroartemisinin with succinic anhydride, in the presence of trialkylamines and their mixture in a low boiling, neutral water miscible, inert organic solvent or solvent mixture at 20-60°C in 0.5 hours and the artesunic acid is then isolated directly at pH 5 to 8 in 91.8 to 97.2% yield.

The above mentioned methods carry some disadvantages being less cost effective and more time consuming as compared to the present invention it should be noted that all the above referenced methods require two separate steps to convert artemisinin into 10-esters of dihydroartemisinin i.e. (a) reduction of artemisinin into dihydroartemisinin in the first pot following by isolation of dihydroartemisinin, and (b) esterification of dihydroartemisinin into different esters in the second pot.

Further, solvent pyridine or 1,2 dichloroethane and catalyst, 4 (N, N-dimethylamino) pyridine used in these processes are not acceptable according to the health standard. Hence there is a need to provide a single step process that overcomes the above-mentioned disadvantages.

EXAMPLE 1

Artemisinin (500mg) and polyhydroxy compound (dextrose, 2.5g) are stirred in 1,4-dioxan (15ml) at room temperature for 5 minutes. Sodium borohydride (2.5g) is added slowly for 10 minutes and the reaction mixture is stirred for about 2 hours at room temperature (20- 30° C). After completion of the reaction (Checked by TLC), succinic anhydride (250 mg) and anion exchange (basic) resin (1.5g) are added at room temperature and the reaction mixture is stirred further for 2 hours at room temperature. Cold water (50 ml) is added to the reaction mixture and pH is adjusted between 6-7 with dilute acetic acid and extracted with 40% ethyl acetate in hexane (3 x 25 ml). The combined extract is washed with water (50 ml). The ethyl acetate π-hexane extract is dried over anhydrous sodium sulphate and evaporation of the solvent yield 655 mg of crude artesunic acid which upon purification over silica gel (1:5 ratio) with 20-30% ethyl acetate in hexane, furnish pure artesunic acid in 93% w/w (465 mg) yield (according to CO-TLC). After drying the pure α-artesunic acid, mp 140-142° C is characterized by spectral analysis.

EXAMPLE 2

Artemisinin (500 mg), polyhydroxy compound (dextrose, 2.0g) are stirred in 1,4-dixan (10 ml). Sodium borohydride (2.5g) is added slowly for 10 minutes and the reaction mixture is stirred for about 2 hours at room temperature (20-30° C). After completion of the reduction step, succinic anhydride (250 mg) and triethylamine (1ml) are added and the reaction mixture is further stirred for 2 hours at room temperature (20-30 degree C). After usual work up and purification of crude product (690mg) through column chromatography (1:4 ratio) 91.2%) pure artesunic acid is obtained.

EXAMPLE 3 Artemisinin (500 mg), polyhydroxy compound (dextrose, 2.0g) are stirred in tetrahydrofuran (10 ml). Sodium borohydride (2.5g) is added slowly for 10 minutes and the reaction mixture is stirred for about 2 hours at room temperature. After completion of the reduction step succinic anhydride (250 mg) and triethylamine (1ml) are added and the reaction mixture is further stirred for 2 hours at room temperature. After usual work up and purification of the crude product (615mg) through column chromatography 87.4% pure artesunic acid is obtained.

EXAMPLE 4

Artemisinin (500 mg) and polyhydroxy compound (dextrose, 2g) are stirred in dioxan (15 ml) for 5 minutes. Sodium borohydride (2.4gm) is added slowly and the reaction mixture is stirred for 2 hours at room temperature (20-30 degree C). After completion of the reduction step succinic anhydride (250 mg) and sodium bicarbonate (3.5g) are added and the reaction mixture is further stirred for 2 hours. After usual workup and purification of impure reaction product (650 mg), 89.6%w/w pure artesunic acid is obtained.

EXAMPLE 5

Artemisinin (500mg) and cation exchange resin (lg) are stirred in tetrahydrofuran (10ml) at room temperature for 5 minutes. Sodium borohydride (250mg) is added slowly for 10 minutes and the reaction mixture is stirred for about 30 minutes at room temperature (20- 35 degree C). After completion of the reaction succinic anhydride (250mg) and triethylamine (0.7ml) are added at room temperature and the reaction mixture is stirred further for 1 hours at room temperature. The resin is filtered. After usual workup and column chromatography of the crude product (710mg), 480mg of pure artesunic acid (yield

= 96%w/w) is obtained.

EXAMPLE 6

Artemisinin (500mg) and cation exchange resin (lg) are stirred in 1,4 dioxan (10ml) at room temperature for 5 minutes. Sodium borohydride (250mg) is added slowly for 10 minutes and the reaction mixture is stirred for about 30 minutes at room temperature (20-35 degree C). After completion of the reaction succinic anhydride (250mg) and triethylamine (0.7ml) are added slowly at room temperature and the reaction mixture is stirred further for 1.25 hours at room temperature. After usual work up and purification of the crude artesunic acid (680mg) pure product in 91.7% w/w is obtained.

EXAMPLE 7

Artemisinin (500 mg), cation exchange resin (lOg) are stirred in 1,4 dioxan (10 ml). Sodium borohydride (250mg) is added slowly for 10 minutes and the reaction mixture is stirred for about 45minutes at room temperature (20-35 degree C). After completion of the reduction step succinic anhydride (250 mg) and sodium bicarbonate (2.5g) are added and the reaction mixture is further stirred for 1.5 hours at room temperature (20-35 degree C). After usual work up and purification of the crude artesunic acid (630mg) pure product in 85%o w/w yield is obtained.

EXAMPLE 8 Artemisinin (500 mg) and cation exchange resin (lg) are stirred in tetrahydrofuran (15 ml) for 5 minutes. Sodium borohydride (2.4gm) is added slowly and the reaction mixture is stirred for 45 minutes at room temperature (20-35 degree C). After completion of the reduction reaction, succinic anhydride (245 mg) and sodium bicarbonate (3.5g) are added and the reaction mixture is further stirred for 1.25 hours. After usual workup and purification of impure reaction product (650 mg), pure artesunic acid in 93%w/w yield is obtained.

EXAMPLE 9

Artemisinin (lOOmg) and cation exchange resin (200mg) are stirred in tetrahydrofuran (3ml) at room temperature for 5 minutes. Sodium borohydride (50mg) is added slowly for 10 minutes and the reaction mixture is stirred for about 30 minutes at room temperature (20-35 degree C). After completion of the reaction propionic anhydride (0.5ml) and triethylamine (0.2ml) are added at room temperature and the reaction mixture is stirred further for 1.5 hours at room temperature. After usual workup and purification of the crude products through preparative TLC 44 mg of pure dihydroartemisinin 10- propionate characterized by its spectral analysis is obtained.

EXAMPLE 10

Artemisinin (lOOmg) and cation exchange resin (200mg) are stirred in tetrahydrofuran (3ml) at room temperature for 5 minutes. Sodium borohydride (50mg) is added slowly for

10 minutes and the reaction mixture is stirred for about 30 minutes at room temperature (20-35 degree C). After completion of the reaction chloroacetic anhydride (50mg) and triethylamine (0.2ml) are added at room temperature and the reaction mixture is stirred further for 1.5 hours at room temperature. After usual workup and purification of the crude products through preparative TLC 35mg of pure dihydroartemisinin 10- chloroacetate characterized by its spectral analysis is obtained.

EXAMPLE 11

Artemisinin (lOOmg) and cation exchange resin (200mg) are stirred in tetrahydrofuran (3ml) at room temperature for 5 minutes. Sodium borohydride (50mg) is added slowly for 10 minutes and the reaction mixture is stirred for about 30 minutes at room temperature (20-35 degree C). After completion of the reaction acetic anhydride (50mg) and triethylamine (0.2ml) are added at room temperature and the reaction mixture is stirred further for 1.5 hours at room temperature. After usual workup and purification of the crude products through preparative TLC 42mg of pure dihydroartemisinin 10-acetate identified by its spectral analysis is obtained.

EXAMPLE 12

Artemisinin (5g) and cation exchange resin (lOg) are stirred in tetrahydrofuran (60ml) at room temperature for 5 minutes. Sodium borohydride (2.5g) is added slowly for 20 minutes and the reaction mixture is stirred for about 1 hour at room temperature (20-35 degree C). After completion of the reaction succinic anhydride (2.5g) and triethylamine (6ml) are added at room temperature and the reaction mixture is stirred further for 1.5 hours at room temperature. After usual workup and purification of the crude product

(6.92g) through CC pure artesunic acid in 94.6%w/w yield is obtained.

ADVANTAGES OF THE PRESENT INVENTION

1. The two pot reactions: reduction of artemisinin into dihydroartemismin and esterification of dihydroartemisinin to artesunic acid carried out in one pot avoids the process of isolation of dihydroartemisinin is avoided which saves chemicals, labour and losses of dihydroartemisinin in isolating it.

2. Conversion of artemisinin into artesunic acid in one pot takes place in about 2-5 hours and is a less time consuming method as compared to previously reported methods in which conversion of artemisinin into dihydroartemisinin in first pot followed by isolation of dihydroartemisinin and its esterification into artesunic acid in the second pot is also a long process. 3. The conversion of artemisinin into artesunic acid in one pot is carried out at room temperature (20-35 degree C) and thereby avoids use of cooling unit.

4. The solvent used to carry out the reduction reaction is also being used in esterification and thus enabling the process cost effective.

5. The catalysts, polyhydroxy compound or cation exchange resin used to carry out the reduction of artemisinin into dihydroartemisinin at room temperature (20-35°C) are cost effective.

6. The conversion of artemisinin into crude artesunic acid followed by workup and purification to yield pure product takes 6-10 hours as compared to previously reported methods (about 20-40 hours) and thus the process is less time consuming.

7. The yield of final product in the present invention i.e. pure artesunic acid is upto 96%, w/w.

8. Thus, this improved process which avoids the disadvantages of previously known process is suitable for the preparation of artesunic acid in large scale.

References

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  2.  World Health Organization. “Guidelines for the treatment of malaria; Second edition 2010”. World Health Organization. Retrieved 10 January 2014.
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  4.  South East Asian Quinine Artesunate Malaria Trial (SEAQUAMAT) (2005). “Artesunate versus quinine for treatment of severe falciparum malaria: a randomised trial”. The Lancet 366 (9487): 717–725. doi:10.1016/S0140-6736(05)67176-0. PMID 16125588.
  5. Jump up^ Sinclair, D; Donegan, S; Isba, R; Lalloo, DG (Jun 13, 2012). “Artesunate versus quinine for treating severe malaria.”. The Cochrane database of systematic reviews 6: CD005967.doi:10.1002/14651858.CD005967.pub4. PMID 22696354.
  6. Jump up^ WHO (2007). Assessment of the safety of artemisinin compounds in pregnancy. World Health Organization, Geneva.
  7. Jump up^ Boulangier D, Dieng Y, Cisse B, et al. (2007). “Antischistosomal efficacy of artesunate combination therapies administered as curative treatments for malaria attacks”. Trans R Soc Trop Med Hyg 101 (2): 113–16. doi:10.1016/j.trstmh.2006.03.003.PMID 16765398.
  8. Jump up^ Clark RL (2012). “Effects of artemisinins on reticulocyte count and relationship to possible embryotoxicity in confirmed and unconfirmed malarial patients”. Birth defects research. Part A, Clinical and molecular teratology 94 (2): 61–75.doi:10.1002/bdra.22868.
  9.  Rolling T, Agbenyega T, Issifou S, et al. (2013). “Delayed hemolysis after treatment with parenteral artesunate in African children with severe malaria—a double-center prospective study.”. J Infect Dis 209 (12): 1921–8. doi:10.1093/infdis/jit841.PMID 24376273.
  10.  Clark RL (2013). “Hypothesized cause of delayed hemolysis associated with intravenous artesunate.”. Med Hypotheses 82 (2): 167–70.doi:10.1016/j.mehy.2013.11.027. PMID 24370269.
  11.  Clark RL (2009). “Embryotoxicity of the artemisinin antimalarials and potential consequences for use in women in the first trimester.”. Reprod Toxicol 28 (3): 285–96.doi:10.1016/j.reprotox.2009.05.002. PMID 19447170.
  12.  Lisewski, A. M.; Quiros, J. P.; Ng, C. L.; Adikesavan, A. K.; Miura, K; Putluri, N; Eastman, R. T.; Scanfeld, D; Regenbogen, S. J.; Altenhofen, L; Llinás, M; Sreekumar, A; Long, C; Fidock, D. A.; Lichtarge, O (2014). “Supergenomic Network Compression and the Discovery of EXP1 as a Glutathione Transferase Inhibited by Artesunate”. Cell 158(4): 916–28. doi:10.1016/j.cell.2014.07.011. PMID 25126794. edit
  13. White NJ (2008). “Qinghaosu (Artemisinin): The price of success”. Science 320 (5874): 330–334. doi:10.1126/science.1155165. PMID 18420924.

Literature References:

Derivative of artemisinin, q.v. Prepn: China Cooperative Research Group on Qinghaosu, J. Tradit. Chin. Med. 2, 9 (1982).

Absolute configuration: X.-D. Luo et al., Helv. Chim. Acta 67, 1515 (1984).

GC/MS determn.: A. D. Theoharideset al., Anal. Chem. 60, 115 (1988);

HPLC determn in plasma: H. Naik et al., J. Chromatogr. B 816, 233 (2005).

Pharmacology: Y. Zhao, J. Trop. Med. Hyg. 88, 391 (1985). Antimalarial activity: W. Peters et al., Ann. Trop. Med. Parasitol. 80, 483 (1986); A. J. Linet al., J. Med. Chem. 30, 2147 (1987).

Inhibition of cytochrome oxidase: Y. Zhao et al., J. Nat. Prod. 49, 139 (1986).

Toxicology: China Cooperative Research Group on Qinghaosu, J. Tradit. Chin. Med. 2, 31 (1982).

Series of articles on chemistry, pharmacology, and antimalarial efficacy: ibid. 3-50.

Clinical trial as add-on therapy in pediatric malaria: L. von Seidlein et al.,Lancet 355, 352 (2000).

Review: R. N. Price, Expert Opin. Invest. Drugs 9, 1815-1827 (2000).

THE CHEMISTRY AND SYNTHESIS OF QINGHAOSU DERIVATIVES” JOURNAL OF TRADITIONAL CHINESE MEDICINE, BEIJING, CN, vol. 2, no. 1, 1982, pages 9-16, XP008019918 ISSN: 0255-2922
2 * DATABASE CAPLUS [Online] CHEMICAL ABSTRACTS SERVICE, COLUMBUS, OHIO, US; PHAN DINH CHAU ET AL: “Semisynthesis of an antimalarial artesunate” retrieved from STN Database accession no. 119:249761 XP002250029 -& TAP CHI DUOC HOC (1992), (5), 10-12 , XP001162710
3 * HAYNES, RICHARD K. ET AL: “C-10 ester and ether derivatives of dihydroartemisinin – 10-.alpha. artesunate, preparation of authentic 10-.beta. artesunate, and of other ester and ether derivatives bearing potential aromatic intercalating groups at C-10” EUROPEAN JOURNAL OF ORGANIC CHEMISTRY (2002), (1), 113-132 , XP002250027
4 * LI Y ET AL: “Studies on artemisinine analogs. I. Synthesis of ethers, carboxylates and carbonates of dihydroartemisinine” YAO HSUEH HSUEH PAO – ACTA PHARMACEUTICA SINICA, BEIJING, CN, vol. 16, no. 6, June 1981 (1981-06), pages 429-439, XP002119789 ISSN: 0513-4870

Artesunate

How does Artesunate kill cancer?

Artesunate is a drug that was initially designed for combating malaria, however, recently it has shown great promise as a cancer therapy1,2,3. It has been used in combination with some chemotherapies to improve outcomes in advanced cancer patients5. When fighting cancer it is important to use every tool at your disposal to weaken the cancer and strengthen your own cells. Artesunate is another weapon in the arsenal of natural remedies that can make a significant difference in the fight against cancer.

The mechanism of action for artesunate in the context of cancer therapy is very well defined. Cancer cells have a tendency to absorb iron at high levels and this is thought to accelerate the mutation rate within these cells. Iron reacts with oxygen to form free radicals, which are reactive molecules that damage DNA. In normal cells this reaction is a problem; in cancer cells it allows them to mutate and develop resistance to therapies. Artesunate activates mitochondrial apoptosis by iron catalyzed lysosomal reactive oxygen species production4. In other words, this drug will use the iron within the cancer cells against them.

http://yaletownnaturopathic.com/how-does-artesunate-kill-cancer/

Dr. Adam McLeod is a Naturopathic Doctor (ND), BSc. (Hon) Molecular biology, First Nations Healer, Motivational Speaker and International Best Selling Author. He currently practices at his clinic in Vancouver, British Columbia where he focuses on integrative oncology. http://www.yaletownnaturopathic.com
References:

1) MIYACHI, HAYATO, and CHRISTOPHER R. CHITAMBAR. “The anti-malarial artesunate is also active against cancer.” International journal of oncology 18 (2001): 767-773.

2) Michaelis, Martin, et al. “Anti-cancer effects of artesunate in a panel of chemoresistant neuroblastoma cell lines.” Biochemical pharmacology 79.2 (2010): 130-136.

3) Du, Ji-Hui, et al. “Artesunate induces oncosis-like cell death in vitro and has antitumor activity against pancreatic cancer xenografts in vivo.” Cancer chemotherapy and pharmacology65.5 (2010): 895-902.

4) Efferth, Thomas, et al. “Enhancement of cytotoxicity of artemisinins toward cancer cells by ferrous iron.” Free Radical Biology and Medicine 37.7 (2004): 998-1009.

5) Zhang, Z. Y., et al. “[Artesunate combined with vinorelbine plus cisplatin in treatment of advanced non-small cell lung cancer: a randomized controlled trial].” Zhong xi yi jie he xue bao= Journal of Chinese integrative medicine 6.2 (2008): 134-138.

WormwoodArtesunate is…

a water-soluble ‘artemesinin’ drug derived from the ‘sweet wormwood’ plant, Artemsia annua, an herb used to treat infections and other illnesses in China for centuries. Interestingly, according to Wikipedia artemsia was lost as an herbal remedy in China until 1970 when an ancient Chinese medical manual dating back to 340 AD was found. The active ingredient in the plant – artemesinin – was isolated by scientists and it anti-malarial properties were quickly noted (1972). It is now used to treat malaria and schistosoma infections.

Artesunate also reduces anti-oxidant activity in the red blood cell thus exposing the cell to high free radical levels. Artesunate is currently being studied as an adjunct to chemotherapeutic agents because of its ability to induce cancerous cells to commit suicide (apoptosis) by inducing high rates of oxidative stress. The ability of the antioxidant NAC to thwart Artesunate’s effects in one study substantiated the important role increased free radical production plays in the drugs effect.

Malaria – Artemesia annua is native to China but has become naturalized around the world including the eastern United States. Artesunate was recently approved for emergency use in patients with severe malaria in the United States.

In April 2009 the FDA approved CoArtem which contains a derivative of artemesinin and a broad spectrum antibiotic called lumefantrine. Upon binding to infected red blood cells artesunate triggers the release of oxygen and carbon-based free radicals that attack proteins in the parasites.

Herpesviruses – Recent culture cell experiments indicated Artesunate was effective at significantly reducing viral protein production in HHV-6A infected cells. A 2005 in vitro study suggested Artesunate significantly reduced cytomegalovirus replication in cells. Because Artesunate effects HHV-6 early in its life cycle it may hold special promise in the kind of smoldering infections that may occur in chronic fatigue syndrome (ME/CFS).

Artesunate’s effects on herpesviruses, however, have not been well studied with just five studies published to date. Interest in this drug appears to be increasing, however, three of the five studies were published in 2008.

Artesunate May Work in Chronic Fatigue Syndrome (ME/CFS) Because..

it may be able to reduce herpesvirus activity in some patients. It’s use, however, is highly experimental.

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