High-Performance Liquid Chromatographic Determination of Isofraxidin in Rat Plasma

Abstract

For the first time a high-performance liquid chromatographic (HPLC) method, with liquid-liquid extraction and ultraviolet (UV) absorbance detection, has been developed for quantification of isofraxidin in rat plasma. The analysis was performed on a Diamonsil C₁₈ column (200 mm × 4.6 mm i.d., 5 µm particle size) with acetonitrile–0.05% phosphoric acid, 26:74 (v/v), as isocratic mobile phase. The linear range was 0.05–8.0 µg mL⁻¹ and the lower limit of quantification was 0.05 µg mL⁻¹. The intra and inter-day relative standard deviation (RSD) for measurement of 0.25, 2.0, and 6.0 µg mL⁻¹ quality-control (QC) samples ranged from 5.7 to 6.4% and from 6.3 to 7.9%, respectively. Accuracy, as relative error (RE), was from ±5.8% to ±7.3%. The method was validated for specificity, accuracy, and precision and was successfully used in a pharmacokinetic study of isofraxidin in rat plasma after administration of Ciwujia extract.