COMPARATIVE-STUDY ON THE DETERMINATION OF CEPHALEXIN IN ITS DOSAGE FORMS BY SPECTROPHOTOMETRY AND HPLC WITH UV-VIS DETECTION

This paper discusses the spectrophotometric determination of cephalexi n as the intact cephalexin or as its acid-induced degradation product. Cephalexin can be determined in the range 1 x 10(-5)-18 x 10(-5) M wi th relative standard deviations of 5-1%. The limits of quantitation an d detection were 10(-5) and 0.3 x 10(-5) M, respectively. These proced ures were compared with reversed-phase HPLC determination. No interfer ence was observed in the presence of common pharmaceutical adjuvants. The H-point standard additions method was applied in order to correct for the possible presence of the cephalexin precursor, 7-aminocephalos poranic acid; this improves the selectivity of the UV-vis spectrophoto metric method.