Pharmacokinetic analysis of alpha and beta epimers of glycyrrhetinic acid in rat plasma: differences in singly and combined administrations.

Hao-Yang Sun, Qing Li, Wei Chen, Lu-Lu Geng, Xi Li, Xiao-Hui Chen, Kai-Shun Bi

School of Pharmacy, Shenyang Pharmaceutical University, Shenyang 110016, China.

Yao xue xue bao = Acta pharmaceutica Sinica 2012 Jan

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An HPLC method for the determination of 18alpha-glycyrrhetinic acid and 18beta-glycyrrhetinic acid in rat plasma was established, which was used subsequently to determine the pharmacokinetic profiles of both epimers of glycyrrhetinic acid in rats. alpha-glycyrrhetinic acid, beta-glycyrrhetinic acid, and a mixture of alpha-glycyrrhetinic and beta-glycyrrhetinic acids were administered to rats via gastric infusion. Blood samples were collected at different time intervals and extracted by liquid-liquid extraction. Separation was achieved by using a Kromasil C18 column (150 mm x 4.6 mm, 5 microm) with the mobile phase composed of acetonitrile--4 mmol x L(-1) ammonium acetate solution (46 : 54, v/v) at a flow rate of 1.0 mL x min(-1), and the detection wavelength was set at 250 nm. The pharmacokinetic parameters were calculated using the software DAS 2.0. In a combined administration, the main pharmacokinetic parameters of beta-glycyrrhetinic acid are significantly different from that of alpha-glycyrrhetinic acid (P < 0.05), while no significant difference was obtained when administrated individually. Compared to the single administration, significant differences (P < 0.05) on the values of AUC(0-t) and AUC(0-infinity) of beta-glycyrrhetinic acid were observed when this chemical was administrated together with alpha-glycyrrhetinic acid. In contrast, the pharmacokinetic parameters of alpha-glycyrrhetinic acid were not affected even under the co-administration. Here, a sensitive, specific, rapid and reproducible HPLC method was developed for the pharmacokinetic studies of alpha-glycyrrhetinic acid and beta-glycyrrhetinic acid in rat plasma.

Citation

Hao-Yang Sun, Qing Li, Wei Chen, Lu-Lu Geng, Xi Li, Xiao-Hui Chen, Kai-Shun Bi. Pharmacokinetic analysis of alpha and beta epimers of glycyrrhetinic acid in rat plasma: differences in singly and combined administrations. Yao xue xue bao = Acta pharmaceutica Sinica. 2012 Jan;47(1):94-100