NOVEL POLYMORPHS OF RIMONABANT

摘要

The present invention discloses novel and stable polymorphs of rimonabant, its hydrates and solvates, to the processes for their preparation and to pharmaceutical compositions comprising them. The present invention further discloses novel and stable amorphous form of rimonabant, process for its preparation and a pharmaceutical composition comprising it. The present invention also provides an improved process for preparation of rimonabant crystalline Form II. Thus, for example, rimonabant is dissolved in methylene dichloride, stirred for 10 minutes at 25 - 30 oC and then distilled off the solvent under vacuum at 40 oC. The resulting residue is stirred with water and the separated solid is collected at 25 - 30 oC to give a stable crystalline rimonabant hydrate.