Liquid chromatographic determination of roxithromycin: Application to stability studies

Abstract

A simple, stability-indicating, reversed-phase liquid chromatographic method has been developed for the determination of roxithromycin in the presence of its forced alkaline, oxidative and ultraviolet degradation products. Reversed-phase chromatography was conducted using an ODS C18 (150 × 4.6 mm i.d.) column at ambient temperature with ultraviolet detection at 215 nm. A mobile phase consisting of 0.03 M potassium dihydrogen phosphate buffer-methanol (40:60, v/v) adjusted to pH 4.5 was used for the separation of the studied drug and its degradation products at a flow rate of 1 mL/min. The method showed good linearity over the concentration range of 10.0-150.0 μg/mL with a detection limit of 2.5 μg/mL and quantification limit of 8.4 μg/mL. The proposed method was successfully applied for the analysis of roxithromycin in its commercial tablets; the obtained results were favorable compared with those obtained by the official method. Furthermore, content uniformity testing of the studied tablets was also conducted. The method was also utilized to investigate the kinetics of the different degradation products of the drug. The first-order rate constant, half-life time and activation energy of the degradation reactions were calculated. © 2012 The Author [2012]. Published by Oxford University Press. All rights reserved.