title: Spectroscopic analytical study for the charge-transfer complexation of certain cephalosporins with chloranilic acid.
abstract: Studies were carried out to develop a simple, rapid and accurate spectrophotometric method for the analysis of fifteen cephalosporins. The method depends on the charge-transfer complexation reaction between any of these drugs as an n-electron donor and p-chloranilic acid (p-CA) as a pi-acceptor to form a violet chromogen measured at 520 nm. Different variables affecting the reaction were studied and optimized. Under the optimum conditions, linear relationships with good correlation coefficients (0.9986-0.9996) were found between the absorbances and the concentrations of the studied drugs in the range of 4-1,200 microg ml(-1). The limits of assay detection ranged from 2.54 to 42.83 microg ml(-1). The accuracy and precision of the method were satisfactory. The method was successfully applied to an analysis of the studied drugs in their pharmaceutical formulations; the recovery percentages ranged from 96.76 +/- 0.87% to 100.50 +/- 1.30%. The interaction sites were confirmed by UV/VIS, IR, 1H-NMR techniques. Molecular modeling for the interaction was used for deriving an equation for calculating the epsilon value for a particular drug. This equation gave a perfect prediction for the degree of interaction of the investigated drugs with the p-CA reagent.
authors.affiliation: Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt. gasaleh@acc.aun.eun.eg
authors.forename: Gamal A
authors.initials: GA
authors.lastname: Saleh
authors.forename: Hassan F
authors.initials: HF
authors.lastname: Askal
authors.forename: Ibrahim A
authors.initials: IA
authors.lastname: Darwish
authors.forename: Abdel-Nasser A
authors.initials: AN
authors.lastname: El-Shorbagi
mesh_terms: D016227:Benzoquinones / Q000737:chemistry*; D002511:Cephalosporins / Q000032:analysis* / Q000737:chemistry; D003116:Color; D004583:Electrons; D008958:Models, Molecular; D004364:Pharmaceutical Preparations / Q000032:analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis
chemical_list: D016227:Benzoquinones; D002511:Cephalosporins; D004364:Pharmaceutical Preparations; C014400:chloranilic acid