A comparative study of LC methods for analysis of cefradine

A comparative study of two isocratic liquid chromatographic methods for the analysis of cefradine is described. The first method is prescribed by the European Pharmacopoeia for the assay of cefradine, using classical alkyl bonded phase (C18) as the stationary phase. Poor reproducibility of the selectivity towards cefradine and its related substances was observed when this method was used and none of the C18 columns examined was able to separate cefradine completely from its potential related substances under the prescribed LC conditions. On the other hand, the second method, which uses poly(styrene-divinylbenzene) as the stationary phase, shows good selectivity even when using columns from different manufacturers and of different age. Four bulk samples of cefradine were analysed following both methods and the results were compared.