Study on the isolation and identification of related substances of Azithromycin

OBJECTIVE To separate and identify the related impurities of Azithromycin.METHODS The related impurities were separated by chromatography and their chemical structures were elucidated with UV,IR,ESIMS, 1H NMR and 13 C NMR methods.RESULTS Four related impurities were isolated from Azithromycin,and one of them was identified preliminarily as 9-deoxo-9α-aza-9α-methyl-9α-homoerythromycin B.CONCLUSION Four related impurities were isolated from Azithromycin for the first time,but it is necessary to further purity and identify three of the related impurities among them.