RP-HPLC Estimation of Cefpodoxime Proxetil in Rat Plasma

Abstract

A validated reverse phase HPLC method was developed for the estimation of cefpodoxime proxetil in rat plasma to determine pharmacokinetic parameters such as peak plasma concentration (C_max), peak time (t_max), area under the curve (AUC_0-24), absorption rate constant K_a and biological half-life (t_½). The samples were chromatographed on a reverse phase column, Luna C₁₈ (250 × 4.6 mm, 5 μm). Detection of cefpodoxime proxetil was carried out at 259 nm using SPDMP 10A photodiode array detector. Mixture of acetonitrile and phosphate buffer (pH 3) (70:30, v/v) was used as mobile phase. Aspirin was used internal standard. The drug was extracted from rat plasma samples by liquid-liquid extraction using methanol as extraction solvent. Calibration curve was linear over the range of 0.05-2 μg/mL of cefpodoxime proxetil. After oral administration of 1.4 mg/kg of rat weight of cefpodoxime proxetil, the plasma concentration-time curve was best confirmed to two-compartment open model. The maximum concentration (Cmax) 3.24 ± 0.037 μg/mL was obtained at time (t_max) of 2.0 ± 0.11 h. The mean area under the curve at 24 h, AUC_0→24 was 39.77 ± 0.03 μg h/mL and at infinity time, AUC_24→8 was 43.48 ± 0.06 μg h/mL. The biological half-life, t_½ was 3.96 ± 0.034 h. The absorption rate constant, K_a was 0.135 ± 0.001 h^-1 and the elimination rate constant, K_e was 0.175 ± 0.002 h^-1.