New spectrophotometric method for determination of cephalosporins in pharmaceutical formulations

A simple, accurate, and precise spectrophotometric method has been proposed for the determination of three cephalosporins, namely: cefixime (cefi), cephalexine, (ceph) and cefotaxime (cefo) in pharmaceutical formulations. Proposed method is based on the derivatization of cephalosporins with 1,2-naphthoquinone-4-sulfonic (NQS). The optimum experimental conditions have been studied. Beer’s law is obeyed over the concentration of 0.5–3, 0.8–2.8, and 0.2–1.2 μg/mL for cefi, ceph, and cefo, respectively.The detection limits were 0.12, 0.168, and 0.0465 μg/mL for cefi, ceph, and cefo, respectively, with a linear regression correlation coefficient of 0.9993, 0.9993, and 0.9994 and recovery in range from 96.5–102.3, 96.04–102.22, and 97.09–99.3 for cefi, ceph, and cefo, respectively. Effects of pH, temperature, reaction time, and NQS concentration on the determination of cefi, ceph, and cefo, have been examined. This method is simple and can be applied for the determination of cefi, ceph, and cefo in pharmaceutical formulations in quality control laboratories.