Spectrophotometric determination of selected cephalosporins in drug formulations using flow injection analysis

A sensitive, accurate and rapid how injection analysis (FIA) method fur the determination of cefotaxime, cefuroxime. ceftriaxone, cefaclor, cefixime, ceftizoxime, and cephalexin is proposed. Aliquots of each cephalosporin wer e hydrolyzed for 15 min with 0.1 M NaOH at 80 degreesC and then oxidized wi th Fe3+ in sulfuric acid medium to produce Fe2+. The produced Fe2+ is then complexed by o-phenanthroline (o-phen) in citrate buffer at pH 4.2 to form the red complex. Fe(v-phen)(3)(2+) ,which exhibits an absorption maximum at 510 nm. Variables such as acidity, reagent concentrations, flow rate of re agents and other FI parameters were optimized to produce the most sensitive and reproducible results. The method was successfully applied to the analy sis of pharmaceutical preparations. The results have been compared with tho se obtained using the official methods. Excellent agreement between the res ults of the proposed method and the official methods was obtained. (C) 2001 Elsevier Science B.V. All rights reserved.