Simultaneous determination of azithromycin and levo oxacin in pharmaceuticals by charge transfer complexation with alizarin red S using an absorption-factor method

Abstract

A new approach based on a selective charge transfer reaction with alizarin red S is described for the simulta- neous determination of azithromycin and levo oxacin in their binary mixtures using an absorption-factor spectrophoto- metric method. Native absorbance was used for the determination for levo oxacin, while a charge transfer complexation of alizarin red S served as the basis for the quantitation of azithromycin. The reaction of azithromycin with alizarin red S was possible in methanol under neutral conditions within 15 min at 25 ◦ C. The conditions were suitably optimized for selective complexation of azithromycin with minimal interference from levo oxacin. The calibration curve was lin- ear over the concentration range of 4.0{20 g mL