Aripiprazole (OPC-14597, OPC-31, BMS-337039) cas no 129722-12-9

Aripiprazole is a psychotropic drug that is available as ABILIFY® (aripiprazole) Tablets, ABILIFY DISCMELT® (aripiprazole) Orally Disintegrating Tablets, ABILIFY® (aripiprazole) Oral Solution, and ABILIFY® (aripiprazole) Injection, a solution for intramuscular injection.

Abilify 2mg tablets (US)

Aripiprazole is 7-[4-[4-(2,3-dichlorophenyl)-1- piperazinyl]butoxy]-3,4-dihydrocarbostyril. The empirical formula is C₂₃H₂₇Cl₂N₃O₂ and its molecular weight is 448.38.

ABILIFY Tablets are available in 2 mg, 5 mg, 10 mg, 15 mg, 20 mg, and 30 mg strengths. Inactive ingredients include cornstarch, hydroxypropyl cellulose, lactose monohydrate, magnesium stearate, and microcrystalline cellulose. Colorants include ferric oxide (yellow or red) and FD&C Blue No. 2 Aluminum Lake.

ABILIFY DISCMELT Orally Disintegrating Tablets are available in 10 mg and 15 mg strengths. Inactive ingredients include acesulfame potassium, aspartame, calcium silicate, croscarmellose sodium, crospovidone, crème de vanilla (natural and artificial flavors), magnesium stearate, microcrystalline cellulose, silicon dioxide, tartaric acid, and xylitol. Colorants include ferric oxide (yellow or red) and FD&C Blue No. 2 Aluminum Lake.

ABILIFY Oral Solution is a clear, colorless to light yellow solution available in a concentration of 1 mg/mL. The inactive ingredients for this solution include disodium edetate, fructose, glycerin, dl-lactic acid, methylparaben, propylene glycol, propylparaben, sodium hydroxide, sucrose, and purified water. The oral solution is flavored with natural orange cream and other natural flavors.

ABILIFY Injection is available in single-dose vials as a ready-to-use, 9.75 mg/1.3 Ml (7.5 mg/mL) clear, colorless, sterile, aqueous solution for intramuscular use only. Inactive ingredients for this solution include 150 mg/mL of sulfobutylether β-cyclodextrin (SBECD), tartaric acid, sodium hydroxide, and water for injection.

Wednesday, February 6, 2013

Otsuka Pharmaceutical Co. Ltd. announced today that the European Medicines Agency (EMA) has approved a label extension for aripiprazole for the treatment up to 12 weeks of moderate to severe manic episodes in Bipolar I Disorder in adolescents aged 13 and older.

Aripiprazole, 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]-butoxy}-3,4-dihydro carbostyril or 7-{4-[4-(2,3-dichlorophenyl)-1-piperazinyl]-butoxy}-3,4-dihydro-2 (1H)-quinolinone, is an atypical antipsychotic agent useful for the treatment of schizophrenia (U.S. Pat. No. 4,74,416 and U.S. Pat. No. 5,006,528). Schizophrenia is a common type of psychosis characterized by delusions, hallucinations and extensive withdrawal from others. Onset of schizophrenia typically occurs between the age of 16 and 25 and affects 1 in 100 individuals worldwide. It is more prevalent, than Alzheimer’s disease, multiple sclerosis, insulin-dependent diabetes and muscular dystrophy. Early diagnosis and treatment can lead to significantly improved recovery and outcome. Moreover, early therapeutic intervention can avert costly hospitalization.

Aripiprazole (Aripiprazole) is an atypical antipsychotic, on 15 November 2002 by the U.S. FDA clearance to market, its efficacy is through the dopamine D2 receptor and serotonin 5HT1A receptor partial agonist activity and serotonin 5HT2A receptor antagonism activity mediated common. With its unique mechanism of action and safety assessment, aripiprazole known as third-generation antipsychotic drugs.

[0003] Aripiprazole is a quinolinone derivative, developed by the Japanese company Otsuka Pharmaceutical, the chemical name

Is: 7 – {4 – [4 – (2,3 – dichlorophenyl)-1_ piperazinyl] butoxy} -3,4 – dihydro-quinolone, the following structural formula:

[0004]

[0005] For the preparation of aripiprazole, Japanese OtsukaPharmaceutical’s patent EP 0367141A2, and related patents US4234585, CN89108934 preparation methods described in 5. In addition, the patent CN1450056A, CN1562973A, CN1784385A, CN1680328A, CN1576273A, etc. describe some of these five Preparation

Method is very similar way. These preparation methods are direct or indirect use of 7 – hydroxy -3,4 – dihydro – quinolin-2 – one (HCS) that the key to higher prices of raw materials, and some methods involve harsh reaction conditions, poor selectivity, low yield, but also increases the cost of industrial production of the product.

[0006] Chinese patent CN1304373C preparation method is not described in the 7 – hydroxy-3 ,4 _ dihydro-2_ (1H) – quinoline

Quinolone intermediates for their preparation of the core reaction is as follows:

[0007]

[0008] This reaction is Friedel-Crafts alkylation reaction, there is a harsh reaction conditions, the yield is low, the reaction selectivity is poor, the shortcomings of high emissions, is not conducive to industrial mass production. SUMMARY OF THE INVENTION

[0009] In order to solve the above problems, the present invention provides a simple, high selectivity, high yield, low cost, environmentally friendly, easy to prepare industrialization aripiprazole and intermediates thereof.

[0010] The technical solution of the present invention, the present invention provides in one aspect a process for preparingaripiprazole novel intermediates.

[0011] The present invention, on the other hand provides a method for the preparation of intermediates.

[0012] The present invention provides the use of the other intermediates for preparing aripiprazole two new preparation methods.

[0013] Specifically, the present invention relates to novel intermediates, compounds of formula ⑴:

[0014]

[0015] wherein, R is selected from methyl, ethyl, propyl, isopropyl, butyl, t-butyl, benzyl and other common alkyl groups in any one, and preferably is ethyl.

[0016] Compound of formula ⑴: 3 – (4 – (4 – (4 – (2,3 _-dichlorophenyl)-piperazinyl) butoxy) _2_ nitrophenyl) propionate, is the following prepared by the procedure:

[0017] Step one, the acylation reaction: with 4 – methyl – 3 – nitro-phenol (VIII) and acetic anhydride as the raw material, DMAP as catalyst, to give 4 – methyl – 3 – nitrophenyl acetate ( VII).

[0018] wherein 4 – methyl – 3 – nitro-phenol (VIII), acetic anhydride, DMAP molar ratio is preferably 1: 1.0 to 1.4: 0.05, at room temperature, the reaction time is preferably 0.5 to 3 hours.

[0019] Step two, the bromination reaction: The resulting product, 4 to Step one – methyl – 3 – nitrophenyl acetate (VII), N-bromosuccinimide and benzoyl peroxide as a raw material , carbon tetrachloride solvent reflux, to give 4 – bromomethyl-3 – nitrophenyl acetate (VI).

[0020] wherein 4 – methyl – 3 – nitrophenyl acetate (VII), N-bromosuccinimide, benzoyl peroxide molar ratio is preferably 1: 1 to 1.2: 0.05, reaction time is preferably 4-18 hours.

[0021] Step three, instead of the reaction: in an appropriate solvent, adding an alkaline agent and diethyl malonate was stirred in an ice bath, was added dropwise step two the resulting product, 4 – bromomethyl-3 – nitrophenyl yl acetate (VI) solution after completion of the addition reaction of 1 to 3 hours to obtain a brown liquid product, 2 – (4_ acetoxy-2 – nitrobenzyl) malonate (V).

[0022], wherein the alkali agent is a common organic or inorganic base selected from sodium methoxide, sodium ethoxide, sodium hydride, sodium tert-butoxide or potassium tert-butoxide, preferably sodium tert-butoxide; the solvent is selected from tetrahydrofuran, methanol, ethanol, butanol, tert-butanol, toluene or N, N-dimethylformamide; 4 – bromomethyl-3 – nitrophenyl acetate (VI), alkaline agent and lipid diethyl molar ratio is preferably 1: 1.0 to 1.8: 1.0 to 1.4.

[0023] Step 4 Hydrolysis decarboxylation: the product obtained in Step Three 2 – (4_ acetoxy-2 – nitro-benzyl)-malonic acid diethyl ester (V) was added concentrated hydrochloric acid and a suitable solvent, heating and stirring reflux, to give a yellow solid product 3 – (4_ hydroxy-2 – nitrophenyl) propionic acid (IV).

[0024] wherein the solvent is selected from water, methanol, ethanol or acetic acid, water soluble solvent, was heated with stirring under reflux time is preferably 3 to 18 hours. [0025] Step five, the esterification reaction: the product obtained in step 4, 3 – (4 – hydroxy-2 – nitrophenyl) propionic acid (IV) was added to an appropriate solvent, the mixture was stirred in an ice bath, was added dropwise thionyl sulfone, after completion of the addition reaction of 1 to 3 hours, to give a pale brown liquid product 3 – (4 – hydroxy-2 – nitrophenyl) propionate (III).

[0026] wherein the solvent is selected from anhydrous methanol, ethanol, propanol, isopropanol, butanol, t-butanol, benzyl alcohol, alcohol and other common solvents.

[0027] Step VI substitution reaction: 1,4 – dibromobutane was added to an appropriate solvent and an alkaline reagent, heated to 50 ~ 100 ° C, the product obtained was added dropwise Step Five 3 – (4_ hydroxy – nitrophenyl) propionate (III) solution, after the addition was complete the reaction was kept 2 to 4 hours to obtain a brown liquid product 3 – (4 – (4 – bromo-butoxy)-2 – nitrophenyl) propionate (II).

[0028] wherein the solvent is selected from methanol, 95% ethanol, ethanol, acetonitrile and N, N-dimethylformamide, and the like; said alkaline agent is a common organic or inorganic weak base, such as triethylamine, pyridine, potassium carbonate, sodium carbonate, etc..

[0029] Step 7 condensation reaction: the product obtained in Step Six 3 – (4 – (4 – bromo-butoxy)-2 – nitrophenyl) propionate (II) adding a suitable solvent, (2,3 – dichlorophenyl)-piperazine hydrochloride 1_, alkaline reagents and catalysts, to obtain

The intermediate product 3 – (4 – (4 – (4 – (2,3 – dichlorophenyl)-piperazin-1 – yl) butoxy)-2 – nitrophenyl) propionate ⑴.

[0030] Among them, 3 – (4 – (4 – (4 – (2,3 _-dichlorophenyl)-piperazinyl) butoxy) _2_ nitrophenyl) propionate (I), (2, 3 – dichloro-phenyl)-piperazine hydrochloride 1_, alkaline reagents and catalysts, the four molar ratio is preferably 1: 0.9 to 1.0: 2.0 to 2.2: 0.05 to 0.5. The solvent is selected from methanol, ethanol and N, N-dimethylformamide, acetonitrile and the like. Step six of the alkaline reagent and alkaline reagent used in the same, said catalyst is a common low-iodine salts, such as sodium iodide, potassium iodide.

[0031] The present invention provides two other hand, the use of a compound of formula ⑴ preparing aripiprazole new method.

[0032] Method one: ⑴ intermediate compound of formula in an appropriate solvent in the acid or salt or a base in the presence of a reducing agent under the action of restoring ring closure reaction to obtain aripiprazole.

[0033] Method one reductive cyclization of the reducing agent used is iron, zinc, sodium sulfide, stannous chloride, and preferably iron; reaction solvent is selected from water, methanol, ethanol, ethyl acetate or in one or more of the mixed solvent; said acid is a common organic or inorganic acid, preferably acetic acid or hydrochloric acid; said salt is a common inorganic or organic salts selected from chloride, ferrous chloride, , ammonium sulfate, calcium chloride, zinc chloride, sodium chloride, sodium bromide or sodium acetate and the like; common said base is an inorganic base selected from sodium hydroxide, potassium hydroxide or sodium bicarbonate; the reduction ring-closing reaction temperature range of 30 ~ 140 ° C, preferably about 80 ° C; reaction time ranges from about 0.5 to 8 hours, preferably 2 hours.

[0034] Method two: ⑴ intermediate compound of formula in an appropriate solvent in the first catalyst, the reduction reaction, and then carried out in a suitable solvent can be prepared by cyclization of aripiprazole.

[0035] The reduction reaction of the second approach, the reducing agent is hydrogen or a carboxylic acid; the catalyst is selected from molybdenum, molybdenum dioxide or Raney nickel, preferably Raney nickel; the solvent is selected from methanol, ethanol, ethyl acetate or acetic acid, preferably ethanol; said ring-closing reaction of the solvent is selected from N, N-dimethylformamide, trichlorobenzene or xylene; reaction temperature range of 50 ~ 180 ° C, preferably about 70 ~ 150 ° C; reaction time the range of about 1 to 8 hours.

[0036] In summary, the present invention is described for preparing aripiprazole method in 4– methyl – 3 – nitro-phenol (VIII) as a starting material, by acetylation protected hydroxy, radical instead of 4 – bromomethyl-3 – nitrophenyl acetate (VI), the diethyl malonate and a nucleophilic substitution reaction to obtain 2 – (4_ acetoxy-2 – nitrobenzyl ) malonic acid diethyl ester (V), which is decarboxylated by hydrolysis, esterification, to give 3 – (4 – hydroxy-2 – nitrophenyl) propionate (III), the reaction product with dibromobutane an ether compounds, and with (2,3 – dichlorophenyl)-piperazine hydrochloride 1_ condensation, to give 3 – (4 – (4 – (4 – (2,3 – dichlorophenyl) piperazine -1 – yl) butoxy) -2 – nitrophenyl) propionate (I), and then by reductive cyclization step, or first reduced and then ring-closing reaction of aripiprazole. The synthetic route of the present invention is as follows: [0037]

According to Example 1 of Japanese Unexamined Patent Publication No. 191256/1990, anhydrous aripiprazole crystals are manufactured for example by reacting 7-(4-bromobutoxy)-3,4-dihydrocarbostyril with 1-(2,3-dichlorophenylpiperadine and recrystallizing the resulting raw anhydrousaripiprazole with ethanol. Also, according to the Proceedings of the 4th Japanese-Korean Symposium on Separation Technology (Oct. 6-8, 1996), anhydrousaripiprazole crystals are manufactured by heating aripiprazole hydrate at 80° C. However, the anhydrous aripiprazole crystals obtained by the aforementioned methods have the disadvantage of being significantly hygroscopic.

The hygroscopicity of these crystals makes them difficult to handle since costly and burdensome measures must be taken in order ensure they are not exposed to moisture during process and formulation. Exposed to moisture, the anhydrous form can take on water and convert to a hydrous form. This presents several disadvantages. First, the hydrous forms of aripiprazole have the disadvantage of being less bioavailable and less dissoluble than the anhydrous forms ofaripiprazole. Second, the variation in the amount of hydrous versus anhydrousaripiprazole drug substance from batch to batch could fail to meet specifications set by drug regulatory agencies. Third, the milling may cause the drug substance, Conventional Anhydrous Aripiprazole, to adhere so manufacturing equipment which may further result in processing delay, increased operator involvement, increased cost, increased maintenance, and lower production yield. Fourth, in addition to problems caused by introduction of moisture during the processing of these hygroscopic crystals, the potential for absorbance of moisture during storage and handling would adversely affect the dissolubility of aripiprazole drug substance. Thus shelf-life of the product could be significantly decreased and/or packaging costs could be significantly increased. It would be highly desirable to discover a form of aripiprazole that possessed low hygroscopicity thereby facilitating pharmaceutical processing and formulation operations required for producing dosage units of an aripiprazole medicinal product having improved shelf-life, suitable dissolubility and suitable bioavailability.

Also, Proceedings of the 4 the Japanese-Korean Symposium on Separation Technology (Oct. 6-8, 1996) state that, anhydrous aripiprazole crystals exist as type-I crystals and type-II crystals; the type-I crystals of anhydrous aripiprazolecan be prepared by recrystallizing from an ethanol solution of aripiprazole, or by heating aripiprazole hydrate at 80° C.; and the type-II crystals of anhydrousaripiprazole can be prepared by heating the type-I crystals of anhydrousaripiprazole at 130 to 140° C. for 15 hours.

By the aforementioned methods, anhydrous aripiprazole type-II crystals having high purity can not be easily prepared in an industrial scale with good repeatability.

Chemical Synthesis of Aripiprazole (active ingredient for Abilify)

Experimental Procedures for the preparation of Aripiprazole (Abilify, aripiprazole)

US 5,006,528 discloses process for the preparation of Aripiprazole in two steps The first step comprises synthesis of 7 -. (4-bromobutoxy) -3,4-dihydrocarbostyril (7-BBQ) by alkylating the hydroxy group of 7-hydroxy-3, 4 -dihydrocarbostyril (7-HQ) with 1 ,4-dibromobutane using potassium carbonate in water at reflux temperature for 3 hours to obtain 7-BBQ in 68% yield The resulting 7-BBQ is further reacted with 1 -. (2,3 – dichlorophenyl)-piperazine to obtain Aripiprazole.

Preparation of 7 – (4-Bromobutoxy) 3 ,4-dihydro-2 (1H) quinolinon ( 7 – (4-Bromobutoxy) 3 ,4-dihydrocarbostyril; 7-BBQ)

7-Hydroxy-3 ,4-dihydro-2 (1H)-quinolinone (aka 7-Hydroxy-3 ,4-dihydrocarbostyril, 60gm) and potassium carbonate (76.3 gm) were taken in acetonitrile (1200ml) at room temperature. To this tetra butyl ammonium iodide (13.7 gm) and 1 ,4-dibromobutane (238.5gm) were added and heated at 40 – 45 ° C for 24 hours Reaction mass was cooled upto room temperature and was filtered off The resulting filtrate was distilled off.. under vacuum. The resultant mass was cooled to 25-30 ° C and cyclohexane (300 ml) was added under stirring. The resulting solid was filtered off and was dried. The resulting solid was taken in water and was stirred for few minutes. The . solid was filtered and dried under vacuum at 55-60 ° C for 20 hours to obtain title compound mp 110.5-111 ° C; 1H NMR (DMSO-d6) ä 1.81 (2H, m,-CH2-), 1.95 (2H , m,-CH2-), 2.41 (2H, t, J) 7 Hz,-CH2CO-), 2.78 (2H, t, J) 7 Hz,-CH2-C-CO-), 3.60 (2H, t, J) 6 Hz,-CH2Br), 3.93 (2H, t, J) 6 Hz, O-CH2-), 6.43 (1H, d, J) 2.5 Hz), 6.49 (1H, dd, J) 2.5, 8 Hz ), 7.04 (1H, d, J) 8 Hz), 9.98 (1H, s, NHCO). Anal. (C13H16NO2Br) C, H, N.

Yield: 73-75%; Purity: 93-95%

Preparation of Aripiprazole (7 – {4 – [4 – (2,3-Dichlorophenyl) piperazin-1-yl] butoxy} 3 ,4-dihydroquinolin-2 (1H)-One)

7 – (4-Bromobutoxy)-l ,2,3,4-tetrahydroquinolin-2-one (50 gm) was taken in acetonitrile (500 ml) at 25-30 ° C. To this potassium carbonate (67.2 gm) and l – (2,3 – dichlorophenyl). piperazine hydrochloride (44.9gm) were added under stirring The reaction mixture was refluxed at 80-85 ° C for 8 hours The reaction mass was cooled to room temperature, filtered and the resulting solid was washed. with acetonitrile. To the resulting solid, water was added and was stirred. The solid was filtered off, washed with water and dried under vacuum at 75-80 ° C for 15 hrs. The resulting crude aripiprazole was crystallized from isopropyl alcohol and water to . obtain title compound Yield: 75-80%; Dimer Impurity: <0.1% 1H NMR:. DMSO-d6 d 9.96 [1H, s, NH]; 7.29 [2H, m, Ar]; 7.13 [1H, q, Ar ]; 7.04 [1H, d, Ar]; 6.49 [1H, dd, Ar]; 6.45 [1H, d, Ar]; 3.92 [2H, t,-CH2-O-]; 2.97 [4H, bb, 2 ( -CH2-)]; 2.78 [2H, t,-CH2-N2-)]; 2.39 [4H, m, 2 (-CH2-)]; 1.73 [2H, m, – CH2-]; 1.58 [2H, m .,-CH2-] IR: cm-1 3193; 2939; 2804; 1680; 1627; 1579; 1520; 1449; 1375; 1270; 1245; 1192; 1169; 1045; 965; 649; 869; 780; 712; 588 .

No Generic Abilify in the US until April 2015

On May 7, 2012, The US Court of Appeals for the Federal Circuit ruled in favor of Otsuka Pharmaceutical Co., Ltd. In its patent litigation against several companies including Israel-based Teva and Weston, Ontario-based Apotex seeking FDA approval to market generic copies of Abilify ®.. The Federal Circuit Affirmed a Decision of the U.S. District Court for the District of New Jersey Holding that the asserted claims ofU.S. Patent No. 5,006,528 Covering aripiprazole, the active Ingredient in Abilify ®, are Valid, THUS Maintaining Patent and Regulatory Protection for Abilify ® in the U.S. until at least April 20, 2015 . The Case is Otsuka Pharma Co.. V. sand Inc.., 2011-1126 and 2011-1127, US Court of Appeals for the Federal Circuit (Washington). The lower court case is Otsuka Pharmaceutical Co. v. Sandoz Inc., 07cv1000, US District Court for the District of New Jersey (Trenton).

Chemical Name for Aripiprazole (Abilify for active Ingredient): 7 – {4 – [4 – (2,3-Dichlorophenyl) piperazin-1-yl] butoxy} 3 ,4-dihydroquinolin-2 (1H)-One
CAS Number 129722 -12-9
aripiprazole chemical name 7 – [4 – [4 – (2,3 – dichlorophenyl) -1 – piperazinyl] butoxy] -3,4 – dihydro-2 ( 1H) – quinolinone

Aripiprazole (, Aripiprazole, Abilify) is an atypical antipsychotic medication for the quinoline derivatives, aripiprazole is a dopamine system stabilizer first, positive and schizophrenia negative symptoms have a significant effect. For the treatment of schizophrenia, the development of Otsuka Pharmaceutical Co., Ltd., in November 15, 2002 by the U.S. Food and Drug Administration (FDA) approval in the U.S., domestic aripiprazole has (Booz clear (brisking, manufacturers : Chengdu Nakasone Pharmaceutical), Austrian (Manufacturer: Shanghai Pharmaceutical Co., Ltd. and Western)) have been approved by the listing in China. On sale in the United States where the law by Bristol-Myers Squibb is responsible. An law where the main patent protection in the United States, and more than three-quarters of its sales from the U.S., patent will expire in April 2015.

Aripiprazole synthetic route

7 – hydroxy-3 ,4. Dihydro -2 (1H) – quinolinone as a starting material, 1,4. Dibromobutane ether to give 7 – (4 – Bromo-butoxy) -3,4 – dihydro – 2 (1H) quinolinone, and then with 1 – (2,3 – dichlorophenyl) piperazine acid condensation aripiprazole (7 – [4 – [4 – (2,3 – dichlorophenyl) -1 – piperazinyl] butoxy] -3,4 – dihydro -2 (1H) – quinolinone)

Aripiprazole preparation method

7 – (4 – Bromo-butoxy) -3,4 – dihydro -2 (1H) – quinolone
A reaction flask was added 7 – hydroxy – 3,4 – dihydro -2 (1H) – quinolone 32.6 g (0.2mol), 1,4 – dibromo butane 129.5g (0.6mol), 11.2% KOH solution 250ml (0.5mol) and DMF975ml, was heated to 60 º C for 2h diluted with 1L water, the aqueous layer with ethyl acetate. acetate (300ml × 2) and the combined organic layers were washed with water, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated under reduced pressure to recover the solvent, the residue was recrystallized from isopropanol, to give 7 – (4 – Bromo-butoxy) – 3,4 – dihydro -2 (1H) – quinolone 38.7g, yield 68%, mp108 ~ 110 º C.

Synthesis of aripiprazole
in the reaction flask was added 7 – (4 – Bromo-butoxy) -3,4 – dihydro -2 (1H) – quinolone, 29.8g (0.1mol), KI25g (0.15mol) 95% Ethanol 596ml, stirred and heated to 60 º C, was added N-2 30min after 3 – dichlorophenyl piperazine 23.1g (0.1mol) and triethylamine 20ml (0.15mol), stirred for 8h at 60 º C the mixture is filtered. crystallization filtrate was cooled, filtered and the filter cake was recrystallized twice from ethanol and dried to obtain aripiprazole 25.6g, yield 57%, mp138.9 ~ 139.6 º C.

emea

Aripiprazole is a new antipsychotic belonging to the class of atypical antipsychotic drugs. It has been proposed that aripiprazole antipsychotic action could be mediated through a combination of partial agonist action at dopamine D2 and serotonin 5-HT1A receptors and antagonism at serotonin 5-HT2A receptors

Aripiprazole is a quinolinone derivative with the chemical name 7-[4-[4-(2,3-dichlorophenyl)-1- piperazinyl]butoxy]- 3,4-dihydro-2(1H)-quinolinone.
The active substance does not contain any chiral centres and does not exhibit any optical isomerism.
Aripiprazole active substance is a white crystalline powder and is practically insoluble in water and its solubility is pH dependent. Therefore, a particle size effect on dissolution of the tablets can be expected. In order to ensure batch-to-batch consistency of the product, and to ensure adequate bioavailability, aripiprazole is subject to milling.
Aripiprazole can exist in several crystalline forms, Form I was chosen for the development and commercialisation.. Aripiprazole is synthesised by a 2-step process. In the first step, 7-hydroxy-3,4-dihydro-2(H)- quinolinone is transformed into an intermediate, which is reacted with 1-(2,3-dichlorophenyl) piperazine hydrochloride to obtain aripiprazole. The process, specifications and control methods are adequately described in the restricted section of the EDMF.

Schizophrenia is a major psychotic disorder. Its essential features consist of a mixture of characteristic
signs and symptoms that have been present for a significant length of time during a 1-month period (or
for a shorter time if successfully treated), with some signs of the disorder persisting for at least 6
months.
The characteristic symptoms of schizophrenia have often been conceptualized as falling into two
broad categories positive and negative (or deficit) symptoms with a third category, disorganized,
recently added because statistical analyses have revealed that it is a dimension independent of the
positive symptom category, where it was previously included. The positive symptoms include
delusions and hallucinations. Disorganized symptoms include disorganized speech (thought disorder)
and disorganized behaviour and poor attention. Negative symptoms include restricted range and
intensity of emotional expression (affective flattening), reduced thought and speech productivity
(alogia), anhedonia, and decreased initiation of goal-directed behaviour (avolition).
The onset of schizophrenia typically occurs during adolescence or early adulthood. It affects men and
women with equal frequency. The peak age at onset for males, however, is the early 20s, and for
women it is the late 20s and early 30s. The majority of patients alternate between acute psychotic
episodes and stable phases with full or partial remission. Inter-episode residual symptoms are
common. This often-chronic illness can be characterized by three phases that merge into one another
without absolute, clear boundaries between them. These phases, which form the structure for
integrating treatment approaches, are described below:
Acute phase. During this florid psychotic phase, patients exhibit severe psychotic symptoms, such as
delusions and/or hallucinations and severely disorganized thinking, and are usually unable to care for
themselves appropriately. Negative symptoms often become more severe as well.
Stabilization phase. During this phase, acute psychotic symptoms decrease in severity. This phase may
last for 6 or more months after the onset of an acute episode.
Stable phase. Symptoms are relatively stable and, if present at all, are almost always less severe than
in the acute phase. Patients can be asymptomatic; others may manifest non-psychotic symptoms, such
as tension, anxiety, depression, or insomnia. When negative (deficit) symptoms and/or positive
symptoms, such as delusions, hallucinations, or thought disorder, persist, they are often present in
attenuated, non-psychotic forms (e.g., circumstantiality rather than looseness, illusions rather than  hallucinations, overvalued ideas rather than delusions).
There are a number of antipsychotics in use but none is ideal in particular because their safety profile  is complex. The in vitro affinity profile of aripiprazole for dopamine and serotonin receptors is similar  to the one of so-called atypical antipsychotics. It is postulated that aripiprazole’s mechanism of action  is novel as it involves a combination of partial agonist action (agonist/antagonism) at dopamine D2  and serotonin 5-HT1A receptors and antagonism at serotonin 5-HT2A receptors.

Aripiprazole is a new antipsychotic belonging to the class of atypical antipsychotic drugs. It has been
proposed that aripiprazole antipsychotic action could be mediated through a combination of partial
agonist at dopamine D2 and serotonin 5-HT1A receptors and antagonism at serotonin 5-HT2A receptors.
The non-clinical characterization of aripiprazole as a dopamine D2 receptor partial agonist at pituitary
lactotrophs predicts a low potential to induce hyperprolactinemia in humans but it may be dose related.
Studies on the sedative liability of aripiprazole suggest a reduced sedative potential compared to
typical antipsychotics. The safety pharmacology profile of aripiprazole r