Determination of paeoniflorin in rat hippocampus by high-performance liquid chromatography after intravenous administration of Paeoniae Radix extract

A rapid and simple high-performance liquid chromatographic (HPLC) assay for the determination of paeoniflorin in rat hippocampus was developed in this study. The chromatographic analysis was carried out using reversed-phase isocratic elution with a Zorbax SB-C18 column, a mobile phase of methanol–water (32:68, v/v), and detection by ultraviolet (UV) absorption at 233 nm. The lower limits of quantitation (LLQ) were 1 μg/ml for paeoniflorin. The calibration curve for paeoniflorin was linear (r=0.9999) over the concentration range of 1–50 μg/ml. The coefficients of variation of intra- and inter-day assays were 7.00, 0.58, 1.46% and 5.48, 1.79, 1.70% at concentrations of 1, 10, 50 μg/ml, respectively. The recoveries of paeoniflorin from rat hippocampus were 98.28±2.14, 98.96±1.48, and 95.34±0.92% at concentrations of 1, 10 and 50 μg/ml, respectively. Stability studies showed that paeoniflorin was stable at temperatures of 2–8 °C in methanol for at least 20 days. The method was applied to determine the time course of paeoniflorin in rat hippocampus, following the administration of a 60 mg/kg i.v. dose of paeoniflorin in Paeoniae Radix extract to a male Wistar rat.