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 lm, 25064.6 mm column thermostated at
568C. 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.