A Robust Liquid Chromatographic Method for the Analysis of Azithromycin in Bulk Samples, Tablets and Suspensions

A simple, isocratic and robust RP-HPLC method for the analysis of azithromycin was developed, validated and applied for the analysis of bulk samples, tablets and suspensions. The optimum chromatographic conditions for separation were established as mobile phase comprising of acetonitrile-0.1M KH2PO4 pH 6.5-0.1M tetrabutyl ammonium hydroxide pH 6.5-water (25:15:1:59% v/v/v/v) delivered at a flow rate of 1.0 ml/min. The stationary phase consisted of reverse-phase XTerra® (250 mm× 4.6 mm i.d., 5 µm particle size) maintained at a temperature of 43 °C with a UV detection at 215 nm. The method was found to be linear in the range 50-150% (r2=0.997). The limits of detection and quantification were found to be 0.02% (20 µg) and 0.078% (78 µg) respectively with a 100.7% recovery of azithromycin. Degradation products of azithromycin in acidic and oxidative environments at 37 °C were resolved from the active pharmaceutical ingredient and thus the method is fit for the purpose.