Document Type: Research article
Department of Chemistry, Faculty of Science Islamic Azad University, Arak Branch, Arak, Iran.
In this study, the direct determination of cefixime as an anti-bacterial agent, in pharmaceutical formulations, urine and human blood plasma was conducted based on spectrophotometric measurements using parallel factor analysis (PARAFAC) and partial least squares (PLS). The calibration set was composed of fourteen solutions in the range of 0.50- 9.00 µg mL-1. PLS models were calculated at each pH applied to determine a set of synthetic cefixime solutions. The best model was acquired at pH 1.02 (PLS-pH 1.02). The ability of the method for the analysis of real samples was considered by determination of cefixime in pharmaceutical preparations, urine and plasma with satisfactory results. The calculated model with PARAFAC showed good prediction capability with root mean square error of prediction (RMSEP) of 0.12 for cefixime. The acid dissociation constants (pKa) of cefixime play a fundamental role in the mechanism of activity of cefixime. The pKa of cefixime were estimated by DATAN program using the corresponding absorption spectra-pH data. The calculated pKa values of cefixime were 1.89 and 3.80 for pKa1 and pKa2 respectively