PROCESSES FOR PREPARATION OF AMORPHOUS AND CRYSTALLINE FORMS OF CANDESARTAN CILEXETIL

摘要

The present invention provides improved processes for the preparation of crystalline and amorphous forms of candesartan cilexetil. In the first embodiment, candesartan cilexetil, e.g. from the reaction mixture after the completed synthesis of candesartan cilexetil, is purified by column chromatography using normal or reverted chromatographic conditions. Fractions containing candesartan cilexetil are joined and lyophilized (freeze-dried) in order to obtain purely amorphous candesartan cilexetil which is optionally converted to forms I and/or II either by crystallization, precipitation, or slurrying. In one of the embodiments, amorphous candesartan cilexetil is thermally converted to form II by heating a slurry of amorphous candesartan cilexetil in an inert solvent or solvent system.