Absorption kinetics of 20(R)-ginsenoside Rh2 in rat intestinal segments

Abstract

Abstract: AIM: To establish a precise and reliable LC/MS assay for determining 20(R)-Ginsenoside Rh2 in rat plasma and to study the absorption kinetics of 20(R)-Ginsenoside Rh2 in different rat intestinal segments.METHODS: Different rat intestinal segments(duodenum , jejunum , ileum and colon)were isolated and ligated respectively , to form a closed intestinal loop model.20(R)-Rh2 was injected into the loop directly at a dose of 9 mg/kg.The blood was harvested at different time points after dosage.Concentrations of 20(R)-Ginsenoside Rh2 in plasma were determined by the LC/MS method.The parameters were calculated.RESULTS: 20(R)-Rh2 had a good linearity from 5 to 1000 ng mL(R2=0.9973)in the LC/MS method established in this paper.The within-day and inter-day precisions were within 15 %,and the accuracy was between 85 %-115 %.After administering in the intestinal loops , the AUC0-6 h were (207±88),(301±49),(157±93)and (172±68)ng·mL ^-1·h for duodenum , jejunum , ileum and colon respectively ,while the absorption rate constant Ka were (3.9±0.4),(1.6±0.4), (1.9±0.8)and (1.1±0.9)/h ,respectively.The peak time t max were(0.44±0.13),(1.75±0.50), (1.13±0.63)and (2.00±1.41) respectively , with the corresponding peak concentrations at (82±17), (110±11), (36±8)and (43±7)ng/mL.CONCLUSION: It is hard for 20(R)-Rh2 to be absorbed in rat intestine.Duodenum and jejunum are its main absorption sites.It is speculated that bad membrane permeability and intestinal efflux transporters are impact factors for its absorption.

Key words: 20 (R)-Ginsenoside Rh2, absorption, pharmacokinetics, intestinal loop, LC/MS

CLC Number:

R965.2

GU Yi, WANG Guang-ji, ZHANG Jing-wei, AI Hua, LV Hua, XIE Hai-tang, JIA Yuanwei, SUN Jian-guo. Absorption kinetics of 20(R)-ginsenoside Rh2 in rat intestinal segments[J]. Chinese Journal of Clinical Pharmacology and Therapeutics, 2009, 14(4): 368-373.

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