Simple , sensitive and accurate derivative and derivative ratio spectrophotometric methods are developed for quantitative estimation of each of cefprozil monohydrate (CZ) , cephapirin sodium (CN) and cefepime hydrochloride (CM), both in mixture with their alkaline degradation products (DCZ1, DCZ2 , DCN or DCM), respectively, and in their pharmaceutical dosage forms. A derivative ratio spectrophotometric method is designed for the simultaneous determination of either (CZ) or (CN) and (DCZ1 or DCN), respectively. For CZ the method involves measurements at 315 and peak-trough at 280-315 nm for CZ and at 331.8 nm for DCZ1. Meanwhile (CN) and (DCN) were quantitatively estimated in ethanol: water (1:1) solvent mixture by measurements at 239.2 and 238 nm, respectively. Moreover, DCN in mixture could be also assayed by recording the second derivative ratio spectra at 333 nm. Another derivative ratio spectrophotometric method permits the determination of either (CZ) or (CM) in presence of (DCZ2 or DCM), respectively, in water. (CZ) is measured at 318.4 nm while (CM) is measured at 250 or 285 and peak-trough at 250-285 nm. In addition first derivative spectrophotometric technique allows the simultaneous quantitative estimation of (CN) and (DCN) at 244 and 345 nm, respectively, in water: ethanol (1:1) mixture. Meanwhile, (DCN) is also successfully quantitated by measuring its absorbance in the zero-order spectrum at 330 nm. Statistical comparison of the results with reference methods indicate no significant differences in accuracy and precision.
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