NOVEL CIMETIDINE POLYMORPH AND PROCESS FOR PREPARING SAME

摘要

The invention relates to the novel polymorph modification "E" of N-cyano-N'-methyl-N''{2-[(5-methyl-imidazol-4-yl)-methylthio]-ethyl}-g uanidine (cimetidine "E") characterized by infrared spectroscopical characteristics. According to the process of the invention cimetidine "E" is prepared by accomplishing an aqueous system, which is supersaturated for N-cyano-N'-methyl-N''-{2-[(5-methylimidazol-4-il)-methylthio]-ethyl}-g uanidine at a temperature below 30 DEG C and contains a water-miscible organic solvent in an amount of at most 40 % by volume, crystallizing the solution or emulsion optionally by adding an inoculating crystal, separating the crystals precipitated, drying them at a temperature below 20 DEG C or removing the water content of the crystals with an organic solvent and subsequently drying them. The novel modification "E" of cimetidine shows better rheological and flowing properties in comparison to those of cimetidine "A" and provides several advantages concerning pharmaceutical technology.