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Efinaconazole is a topical triazole antifungal in development for the treatment of onychomycosis.
Valeant Pharmaceuticals International Inc. announced that the New Drug Submission for Jublia has been approved from the Canadian regulatory authority, Health Canada, for the treatment of mild to moderate onychomycosis, a common and destructive nail infection caused predominantly by dermatophyte fungi.
May 28, 2013 Valeant Pharmaceuticals International, Inc. today announced that it has received a Complete Response Letter (CRL) from the U.S. Food and Drug Administration (FDA) regarding its New Drug Application (NDA) for efinaconazole for the treatment of onychomycosis. A CRL is issued by the FDA’s Center for Drug Evaluation and Research when the review of a file is completed and questions remain that preclude the approval of the NDA in its current form. The questions raised by the FDA pertain only to Chemistry, Manufacturing and Controls (CMC) related areas of the container closure apparatus. As no efficacy or safety issues were raised by the FDA, Valeant believes that these items can be addressed and is working for a timely response to the FDA as soon as possible. Valeant remains committed to bringing efinaconazole to market as a potential new treatment for onychomycosis.
About Valeant Pharmaceuticals International, Inc.
Valeant Pharmaceuticals International, Inc. is a multinational specialty pharmaceutical company that develops, manufactures and markets a broad range of pharmaceutical products primarily in the areas of dermatology, neurology and branded generics. More information about Valeant Pharmaceuticals International, Inc. can be found at www.valeant.com.
(2R,3R)-2-(2,4-difluorophenyl)-3-(4-methylenepiperidin-1-yl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol (nonproprietary name (INN): Efinaconazole, hereinafter sometimes abbreviated as KP-103) which is the compound represented by formula 1 and known to be effective against mycotic diseases in humans and animals (the compound described in Example 1 in Patent Document 1) or salts of this compound.
Methods for obtaining aminoalcohols by the ring-opening addition reaction of epoxides with amines are generally performed at high temperature for a prolonged time using a large excess of amines. Since a large excess of amines are used, the conventional methods give rise to a lot of by-products and require the step of recovering amines; hence, if the amines are expensive, the conventional methods are not desirable not only from the viewpoint of production cost but also as an industrial production process. In order to realize an enhanced reactivity, it has been proposed that the above-described reaction be performed using Lewis acids but the Lewis acids that can be used are either expensive or labile and are not suitable for industrial use; perchlorates or the like are highly toxic and dangerous and because of this low level of safety, they have posed various problems such as the need to take utmost care in use (Non-Patent Documents 1 and 2). It was also reported that by using lithium bromide, the reactivity at room temperature under a solventless condition could be enhanced (Non-Patent Document 3). The method reported in that document uses amines and epoxides that are liquid at ordinary temperature, so its success is probably due to the reaction of the starting materials at high concentrations under a solvnetless condition. It then follows that this method is not applicable to amines and epoxides that are solid at ordinary temperature, especially those with high melting points.
Returning now to the compound of formula 1, it is produced by the ring-opening addition reaction of an epoxide with an amine as described in Patent Document 1. In this production method, (2R,3S)-2-(2,4-difluorophenyl)-3-methyl-2-[(1H-1,2,4-triazol-1-yl)methyl]oxirane (hereunder sometimes abbreviated as “epoxytriazole”) is used as the epoxide and 4-methylenepiperidine (hereunder sometimes abbreviated as “4-MP”) is used as the amine. In this method, the ring-opening addition reaction uses a large excess of 4-MP in water and involves prolonged heating under reflux, so it has the disadvantage that a lot of by-products are generated during reaction and need be removed. As a further problem, 4-methylenepiperidine which is produced by the method described in Patent Document 2 is obtained as dissolved in water, so its purity is low enough to affect the reactivity and impurities are unavoidably generated by the heat applied to the step of isolation by distillation.
The process BELOW for producing the compound of formula (1) which, as formulated below, comprises reacting (2R,3S)-2-(2,4-difluorophenyl)-3-methyl-2-[(1H-1,2,4-triazol-1-yl)methyl]oxirane with an acid addition salt of 4-methylenepiperidine in a reaction solvent in the presence of a hydroxide of an alkali metal or an alkaline earth metal selected from the group consisting of lithium, sodium, calcium, and strontium or a hydrate of the hydroxide:
(where HX signifies the acid in the acid addition salt)