A stability-indicating HPLC method for the separation of clarithromycin and related substances in bulk samples

Abstract

Clarithromycin is a 6-O-methylated semi-synthetic derivative of erythromycin A, which is more resistant towards acid decomposition. Commercial clarithromycin samples contain several potential impurities arising from the manufacturing process and degradation. A simple, selective, and sensitive isocratic liquid chromatographic method has been developed for the impurity profiling of clarithromycin bulk samples. The method employs a XTerra RP18, 5 μm, 250×4.6 mm column thermostated at 56°C. The mobile phase consists of acetonitrile – 0.2 M potassium phosphate buffer pH 6.80 – water (40 : 3.5 : 56.5). Several peaks are of unknown identity. The method is stability indicating.