Vol.2, No.8, 828-840 (2010) Natural Science doi:10.4236/ns.2010.28104 Copyright © 2010 SciRes. Openly accessible at http://www.scirp.org/journal/NS/ Spectophotometric method for determination of certain cephalosporins using 4-chloro-7-nitrobenzo-2-oxa-1, 3-diazole (NBD-Cl) Azza H. Rageh*, Salwa R. El-Shaboury, Gamal A. Saleh, and Fardous A. Mohamed Department of Pharmaceutical Analytical Chemistry, Facutly of Pharmacy, Assiut University, Assiut, Egypt; *Corresponding Author: azhesham@yahoo.com Received 11 February 2010; revised 23 March 2010; accepted 30 March 2010. ABSTRACT A simple, accurate and precise spectropho- tometric method has been proposed for the de- termination of eleven cephalosporins, namely; cefaclor monohydrate, cefadroxil monohydrate, cefalexin anhydrous, cefradine anhydrous, ce- fotaxime sodium, cefoperazone sodium, ceftri- axone sodium, ceftazidime penthydrate, cefa- zolin sodium, cefixime and cefpodoxime pro- xetil in bulk drug and in pharmaceutical formu- lations. The method depends on hydrolysis of the studied drugs using 0.5M NaOH at 100°C and subsequent reaction of the formed sulfide ions with NBD-Cl (4-chloro-7-nitrobenzo-2-oxa-1, 3-diazole) to form a yellow-colored chromogen measured at 390 nm. Different variables affect- ing the reaction (e.g. NaOH concentration, hy- drolysis time, NBD-Cl concentration and dilut- ing solvent) were studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9990- 0.9999) were found in the range of 5-160 μg mL -1 for all studied drugs. The limits of assay detec- tion and quantitiation ranged from 0.289 to 5.867 and from 0.878 to 17.778 μg mL -1 ; respectively. The accuracy and precision of the proposed method were satisfactory. The method was suc- cessfully applied for analysis of the studied drugs in their pharmaceutical formulations and the recovery percentages ranged from 96.6 to 103.5%. Keywords: Spectrophotometry; Cephalosporins; NBD-Cl; Pharmaceutical Analysis 1. INTRODUCTION Cephalosporins have been used since 1948. These anti- biotics have assumed a prominent role in modern antim- icrobial therapy due to enhanced intrinsic microbiologi- cal activities and favorable safety profile. Chemical structures of cephalosporins drive from the 7-aminoce- phalosporanic acid (7-ACA) composed of a β-lactam ring fused with a dihydrothaizine ring (Figure 1), but differ in the nature of substituents at the 3- and/or 7-positions of the cephem ring. These substituents affect either the pharmacokinetic properties (3-position) or the antibacterial spectrum (7-position) of the cephalosporins [1,2]. Traditionally, cephalosporins are divided into first-, second-, third-, and fourth-generation agents. Table 1 shows cephalosporins studied in this work. Several methods have been reported for cephalosporins deter- mination. The official procedures in pharmaceutical preparations utilize high-performance liquid chromatog- raphy (HPLC) [3] which is expensive. Other reported procedures include spectrophotometric [4-9], spectro- fluorimetric [10-13], chemiluminescence [14-16], chro- matographic [17-20] and electrochemical methods [21-24] and most of them are lengthy and/or tedious. The hydrolytic degradation of cephalosporins was very often used as a preliminary step in the analytical procedure used for their determinations [25-32]. The literature reveals that many spectrophotometric methods were developed for cephalosporins determinations that based on hydrolysis of these drugs using alkaline degra- Figure 1. Chemical structure of 7-aminocephalosporanic acid.