Method for obtaining the polymorphic form (II) of pyribedil

Abstract

The subject of the application is a method for obtaining the polymorphic form (II) of piribedil, which is characterized in that the drug in the form of crystalline piribedil, of structural formula 1a in the basic polymorphic form (I) is mixed with an excipient in the form of a graft copolymer of polyvinylcaprolactam-polyvinyl acetate-polyethylene glycol, of structural formula 1b, in a mass ratio of the drug to the excipient in the range from 90:10 to 50:50, preferably 80:20 and is subjected to melting, preferably on a heating plate, previously heated above the melting point of piribedil from 100°C to 150°C, preferably 130°C, is mixed until a homogeneous mixture is obtained, and then vitrified by immediate supercooling of the molten binary mixture, by transferring it to a plate cooled from -20°C to 20°C, preferably 0°C, and most preferably to a temperature of -10°C, until an amorphous binary mixture is obtained,which is then subjected to a recrystallization process at a temperature of 0°C to 90°C, preferably 20°C,