Abstract

Utility of 2,3-dichloro-5,6-dicyano-p-benzo-quinone for kinetic charge transfer determination of certain cephalosporins

Author(s): Mahmoud A.Omar

A simple and rapid kinetic spectrophotometric method has been developed for determination of ceftriaxone, cefixime and cefpodoxime in pure forms and in their pharmaceutical formulations. The method is based on the reaction of these drugs as n-electron donors with 2,3-dichloro-5,6-dicyanop- benzo-quinone (DDQ) as -acceptor. The orange-red colour formed due to the formation of charge transfer complex was monitored spectrophotometrically bymeasuring the absorbance at 460 nm. The factors affecting the reaction were studied and optimized. The stoichiometry of the reaction was determined and the reaction pathway postulated. The initial rate and fixed time methods were utilized for constructing the calibration graphs. The graphswere linear in the concentration ranges of 0.024-1.00mgml-1and 0.024-2.00mgml-1using the initial rate and fixed timemethods respectively. Ultraviolet–visible, infrared and 1H-nuclear magnetic resonance techniques were used to study the formed complex. The analytical performance was fully validated, and the results were satisfactory. The proposed method has been successfully applied for the determination of studied drugs in pharmaceutical formulations and the results obtained were in good agreement with those obtained by the reference methods.