RP-HPLC Estimation of Fexofenadine Hydrochloride in Rat Plasma

Abstract

A validated reverse phase HPLC method was developed for the estimation fexofenadine hydrochloride 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) and biological half-life (t_1/2). The samples were chromatographed on a reverse phase column, Luna C₁₈ (250 mm × 4.6 mm, 5 μm). Detection of fexofenadine HCl was carried out at 220 nm using SPDMP 10A photodiode array detector. Mixture of acetonitrile and 0.5 % phosphate buffer (60:40, v/v) having the pH of 3.5 was used as mobile phase. 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 0.05-2.00 μg/mL of fexofenadine hydrochloride. After oral administration of 10 mg/kg of rat weight of fexofenadine hydrochloride, the plasma concentration-time curve was best confirmed to two-compartment open model. The maximum concentration (C_max) 5.65 ± 2.10 μg/mL was obtained at time (t_max) of 1.00 ± 0.87 h. The mean area under the curve at 24 h, AUC_0→24 was 57.09 ± 17.3 μg h/mL and at infinity time, AUC_24→∞ was 0.35 ± 14.8 μg h/mL. The biological half-life t_1/2 was 2.4 ± 1.65 h.