Stability indicating methods for the determination of cefpodoxime proxetil in the presence of its acid and alkaline degradation products

Four different, accurate, sensitive and reproducible stability-indicating methods for the determination of cefpodoxime proxetil (CPD) in the presence of its acid and alkaline degradation products are presented. The first method is based on derivative spectrophotometry. Second derivative spectrophotometry was applied where CPD was determined at 261 nm in the presence of its acid degradation product and also third derivative spectrophotometry was applied where CPD was determined at 282 nm in the presence of its alkaline degradation product. The second method is based on the first derivative of ratio spectrophotometry ( 1 DD) of CPD at 215 nm and 255 nm in the presence of its acid degradation product and at 243 nm in the presence of its alkaline degradation product. The third method is ratio subtraction spectrophotometry where the drug is determined at 232 nm in laboratory prepared mixtures of CPD and its acid or alkaline degradation product. Calibration graphs were established for 4.0-40.0 μg/ml for CPD determination by the three spectrophotometric methods. The fourth method is an isocratic reversed -phase HPLC procedure, a Zorbax C column was used to separate CPD from its acid and alkaline degradation product using acetonitrile: water: triethylamine (60:40:1, v/v/v) as a mobile phase and detection at 232 nm. The suggested procedures were successfully applied for the analysis of CPD in bulk powder and in pharmaceutical preparations. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by the official method

Stability indicating chemometric methods for the determination of two cephalosporin drugs by partial least squares and principle component regression multivariate calibration methods

In this study, Two multivariate calibration methods, including principal component regression (PCR) and partial least square (PLS), have been used for the determination of two cephalosporin drugs namely cefpodoxime and cefixime in the presence of their acidic and alkaline induced degradation products. Although the components show a large degree of spectral overlap, they have been determined simultaneously and rapidly requiring no separation step. The PCR and PLS techniques are useful chemometric approaches using UV spectral analysis due to the simultaneous inclusion of many spectral wavelengths instead of the single wavelength used in derivative spectrophotometry, thus a great improvement in the precision and predictive abilities of these multivariate calibrations is observed. Spectra of cefpodoxime and cefixime and their acidic and alkaline induced degradation products were recorded at several concentrations within their linear ranges and were used to compute the calibration mixture between wavelengths 200 and 400 nm at an interval of 1 nm in water. PLS and PCR were used for chemometric analysis of data and the parameters of the chemometric procedures were optimized. A calibration set was constructed for the mixture and the best model was used for the prediction of the concentration of the selected drug. The proposed procedures were successfully applied for the determination of cefpodoxime and cefixime in laboratory‐prepared mixtures and in pharmaceutical formulations, with no interference from excipients as indicated by the recovery study results. The validity of the proposed methods was assessed using the standard addition technique