CIMETIDINE POLYMORPH AND PROCESS FOR PREPARING SAME

摘要

2104027 9214713 PCTABS00015 The invention relates to the novel polymorph modification "E" of N-cyano-N'-methyl-N'' 2-¢(5-methyl-imidazol-4-yl)-methylthio!-ethyl -guanidine (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 -guanidine at a temperature below 30 ·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 ·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.