Development and Validation of Spectrophotometric Determination of Cefpodoxime Proxetil in Pure Form and Pharmaceutical Formulation through Ion-Pair Complex Formation Using Bromocresol Purple

A simple, direct and accurate spectrophotometric method has been developed for the determination of cefpodoxime proxetil (CEFP) in pure form and pharmaceutical formulations by complex formation with bromocresol purple (BCP). The method involves the formation of yellow ion-pair complexes between BCP reagent and CEFP in chloroform. The two formed complexes ([CEFP]: [BCP] and [CEFP]: [BCP]₂) have maximum absorption at λ_max 414 nm. The proposed method was validated for specificity, linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and solution stability with an average recovery of 99.2-101.0%.The formed complexes ([CEFP]:[BCP] and [CEFP]:[BCP]2) were measured against the reagent blank prepared in the same manner. Variables were studied in order to optimize the reaction conditions. Molar absorptivity (ε) for two complexes were 10500 and 15700 L.mol-1.cm-1, respectively. Beer's law was obeyed in the concentration range of 0.5576-5.576 and 5.576-55.760 μg/ml in the present of 2x10^-4 and 1x10^-3 mol/l of BCP, respectively, with good correlation coefficient (R²= 0.9988 and R²= 0.9995, respectively). The relative standard deviation did not exceed 4.4%. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.083 and 0.25 μg/ml, respectively. The developed method is applicable for the determination of CEFP in pure and different dosage forms with the average assay of marketed formulations 91.6 to 106.2%, and the results are in good agreement with those obtained by the RP-HPLC reference method.