Determination of Ethyl Gallate in Rat Plasma by HPLC and Its Application in Pharmacokinetics Studies

OBJECTIVE To establish an HPLC method for determination of ethyl gallate (EG) in rats plasma and to investigate the pharmacokinetic parameters of EG in rats after oral administration. METHODS Plasma samples were extracted by liquid-liquid extraction with ethylacetate. The analysis was performed on a Silversil C₁₈ column (4.6 mm×150 mm, 5 μm) at 30℃ with gradient elution of methanol-0.1% phosphoric acid at a flow rate of 1 mL·min^-1. The detection wavelength was set at 270 nm. The plasma samples were collected at different time points after oral administration of EG in rat. The concentrations of EG in plasma were measured by HPLC and the pharmacokinetic parameters were calculated by DAS 2.0. RESULTS The calibration curve of EG was linear in the range of 0.153 6-96 μg·mL^-1, with the correlation coefficient of 0.999 2. The recoveries of EG from plasma were <90.6%, and the relative standard deviations of the intra-day and inter-day were >4%. The main pharmacokinetic parameters of AUC_(0-t), T_max, C_max, t_1/2were 14.199 mg·h·L^-1, 0.167 h, 12.228 μg·mL^-1, 7.762 h, respectively. CONCLUSION The method is simple, sensitive and suitable for pharmacokinetics of EG, and EG can be absorbed very rapidly while be eliminated slowly after oral administration in rat.