A spectrophotometric method for the determination of azithromycin has been developed based on the charge transfer reaction.The reaction between azithromycin and 7,7,8,8-tetracyanoquinodemethane（（TCNQ）） was completed in acetone medium in 30 minutes at 50 ℃.Beer′s law is obeyed in the range of（12.1）867.6 mg/L for the determination of azithromycin.The molar absorptivity of the complex at 745 nm is 1.44×103 L/（mol·cm）.The relative standard deviation is 0.96%（n=10）.The composition ratio of the charge transfer complex was found to be 1∶[KG-*3/5]1 by means of the slope ratio and Job′s methods.This method has been applied to the determination of azithromycin in tablets with satisfactory results compared with the Pharmacopoeia method.Recovery was 100.5%.
