AZITHROMYCIN DIHYDRATE

摘要

72222-84 Disclosed are crystalline azithromycin (9-deoxo-9a-aza-9a-methyl-9a-homoerythromycin) dihydrate and a process for producing the same. The crystalline dihydrate is non-hygroscopic and is easier to prepare and maintain the product in a form having a constant reproducible water content then hygroscopic monohydrate. The dihydrate is produced by crystallization from tetrahydrofuran and aliphatic hydrocarbon in the presence of a sufficient amount of water.