ANALYSIS OF AMPICILLIN, CLOXACILLIN AND THEIR RELATED SUBSTANCES IN CAPSULES, SYRUPS AND SUSPENSIONS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

An assay method for the simultaneous determination of ampicillin (AMP) and cloxacillin (CLOX) from pharmaceutical preparations has been deve loped for assessment of product quality, It utilizes isocratic HPLC em ploying an ion-pairing solvent system, The chromatographic conditions comprised a reversed-phase C-18 column (100 x 2 mm id) with a mobile p hase of acetonitrile-20 mmol l(-1) aqueous phosphate buffer (15 + 85) of pH 2.0 incorporating 100 mmol l(-1) sodium dodecyl sulfate. The flo w rate was 0.4 cm(3) min(-1) and UV detection was used at 230 nm, A ph otodiode array detector was used for examination of peak homogeneity. The method has been validated according to current guidelines includin g assay of pharmacopoeial standard Ampiclox capsules, syrups and neona tal suspensions. In addition to determination of the active ingredient s, AMP and CLOX, the method is capable of simultaneously detecting man ufacturing precursors and acid hydrolysis decomposition products of bo th drugs.