Voltammetric assay of azithromycin in pharmaceutical dosage forms

The oxidative behaviour of azithromycin was studied at s glassy carbon electrode in different buffer system using cyclic, linear sweep and differential pulse voltammetry. The oxidation process was shown to be irreversible over the entire pH range studied (5-11) and was diffusion-adsorption controlled. Analytical method with adequate precision and accuracy was developed for the determination of azithromycin in phosphate buffer at pH 7 as supporting electrolyte containing 10% methanol and 0.05 M ammonium acetate. The peak current varied linearly with azithromycin concentration in the range 1-15 microg/ml. The procedure was successfully applied for assay of the drug in the pharmaceutical dosage forms. The relative standard deviation (n = 5) of 2.18% was obtained.