Simultaneous determination and pharmacokinetic studies of dihydromyricetin and myricetin in rat plasma by HPLC-DAD after oral administration of Ampelopsis grossedentata decoction.

A simple and sensitive high-performance liquid chromatographic method was developed for the simultaneous determination of dihydromyricetin (1) and myricetin (2) in rat plasma after orally administrating the decoction of Ampelopsis grossedentata. Plasma samples were acidified with 0.375% phosphoric acid and extracted with ethyl acetate. Analysis of the extract was performed on reversed-phase C(18) column with a gradient eluent composed of acetonitrile and 0.04% phosphoric acid. The flow rate was kept at 1 ml/min and the detection wavelength was set at 290 and 370 nm for 1 and 2, respectively. The calibration curves were linear in the range of 0.247-4.114 microg/ml and 0.150-2.501 microg/ml for 1 and 2, respectively. The intra-day and inter-day precisions were better than 4.9 and 6.2%, respectively. The limits of detection (LOD) for 1 and 2 in plasma were 21.600 and 52.530 ng/ml, and the limits of quantification (LOQ) were 0.247 and 0.150 microg/ml, respectively. The mean recoveries for 1 and 2 were 92.0 and 93.3%, respectively. The accuracy and precision were well within the acceptable range and R.S.D. of measured rat samples was less than 7.5%. This validated method has been successfully applied in the pharmacokinetics study of dihydromyricetin and myricetin in vivo after orally administrating the decoction of A. grossedentata to rats.