Drug Patent Expiration and Exclusivity
|Active Ingredient||Form||Dosage||Drug Type||Application||Product|
|EMEDASTINE DIFUMARATE||SOLUTION/DROPS; OPHTHALMIC||0.05%||RX||020706||001|
There are 1 patent(s) protecting ALCON’s EMADINE.
The last patent expires on 2013-12-08.
|US5441958||Ophthalmic compositions comprising emedastine and methods for their use
Topical ophthalmic compositions comprising 1-(2-ethoxyethyl)-2-(4-methyl-1-homopiperazinyl)-benzimidazole and its ophthalmically acceptable acid addition salts have been found to be useful in treating allergic conjunctivitis and related ailments.
Exclusivity is marketing rights granted by the FDA to the ALCON.
EMADINE ® (emedastine difumarate ophthalmic solution) 0.05% is a sterile ophthalmic solution containing emedastine, a relatively selective, H1-receptorantagonist for topical administration to the eyes. Emedastine difumarate is a white, crystalline, water-soluble fine powder with a molecular weight of 534.57. The chemical structure is presented below:
lH-Benzimidazole, 1-(2-ethoxyethyl)-2-(hexahydro-4-methyl-1H-1,4-diazepin-1-yl), (E)-2-butenedioate (1:2)
Each mL of EMADINE contains: Active: 0.884 mg emedastine difumarate equivalent to 0.5 mg emedastine. Preservative: benzalkonium chloride0.01%. Inactives: tromethamine; sodium chloride; hydroxypropyl methylcellulose; hydrochloric acid/sodium hydroxide (adjust pH); and purified water. It has a pH of approximately 7.4 and an osmolality of approximately 300 mOsm/kg.
l-(2- ethoxyethyl)-2-(4-methyl-l-homopiperazinyl)-benzimidazole, otherwise known asemedastine, and its ophthalmically acceptable acid addition salts and methods for their use.
Allergic conjunctivitis is frequently characterized by ocular pruritus
(itching), erythema (inflammatory redness), edema and tearing. This condition is one of the most frequently treated by ophthalmologists, optometrists and allergists. To date, treatment has been primarily through the use of topically applied histamine t antagonists in combination with α-agonists. See, for example, the following articles:
1. Miller, J. and E.H. Wolf, “Antazoline phosphate and naphazoline hydrochloride, singly and in combination for the treatment of allergic conjunctivitis – a controlled, double-blind clinical trial.” Ann. Allergy, 35:81-86 (1975). 2. Vandewalker, M.L. et al., “Efficacy of Vasocon-A and its components with conjunctival provocation testing (CPT).” j± Allergy Clin. Immunol., 83:302 (1989). 3. Abelson, M.B. et al., “Effects of topically applied ocular decongestant and antihistamine.” Am. I. Ophthalmol., 90:254- 257 (1980).
Recent studies indicate that the antihistamine levocabastine exhibits clinical activity in patients with allergic conjunctivitis without the addition of a vasoconstrictor. See, Dechant, K.L. and K.L. Goa, “Levocabastine. A review of its pharmacological properties and therapeutic potential as a topical antihistamine in allergic rhinitis and conjunctivitis/’ Drugs, 41:202-224 (1991). In addition, it has recently been demonstrated that Hα antagonists are effective in relieving conjunctival injection (hyperemia) and erythema, as well as pruritus. See, Berdy, G.J. et al., “Allergic conjunctivitis: A survey of new antihistamines.” T. Ocular Pharmacol.. 7:313-324 (1991).
Although there are many different antihistamines available for systemic treatment of allergies and related ailments, many such antihistamines are not suitable for topical ophthalmic use because of limited ocular bioavailability. For example, terfenadine (Seldane®, made by Marion Merrell Dow), astemizole (Hismanal®, made by Janssen Pharmaceutica) and loratadine (Claritin®, made by Schering) all have good systemic activity; however, terfenadine has little or no local ocular activity, and astemizole and loratadine each have greatly reduced local ocular activity (as compared to its systemic activity).