Co-crystal containing S-naproxen and glycine ester and method of its preparation

Abstract

The subject of the application is a cocrystal containing S-naproxen and a glycine ester, according to the invention, which is characterized in that it has the form of Formula wherein the glycine ester is glycine ethyl ester, glycine propyl ester, or glycine butyl ester. The application also covers a method for preparing a cocrystal containing S-naproxen and a glycine ester, characterized in that equimolar amounts of S-naproxen and the glycine ester are dissolved in anhydrous ethanol or chloroform at a temperature of at least 25°C. The resulting solution is then allowed to crystallize, after which the resulting cocrystal is filtered, and the remaining solvent is removed under reduced pressure. Preferably, the chloroform is evaporated from the obtained solution to obtain a precipitate, which is then recrystallized by dissolving it in a solvent. Preferably, anhydrous ethanol, isopropanol or an ethanol:water mixture in a volume ratio of 70:30 is used as the solvent.