Method of preparing form II crystals of clarithromycin

摘要

Pure Form II crystals of clarithromycin can be prepared by a simple, high-yield process comprising the steps of treating crude clarithromycin or different crystal forms of clarithromycin with formic acid in an organic solvent to obtain crystalline clarithromycin formate and neutralizing the clarithromycin formate with a base in a mixture of water and a water-miscible organic solvent.