Asian Journal
Of Traditional Medicines

Abstract: To study the first-pass metabolism of oxymatrine in rats, and to clarify the main site of metabolism following the gastrointestinal site specific delivery of oxymatrine, as a basis on design of dosage forms of oxymatrine. The rats were given oxymatrine 200 μmol/kg by different routes, namely, the stomach, duodenum and ileum. The concentrations of oxymatrine and matrine in the gastrointestinal wall of the administration site, the amount in the contents at the administration site, and the plasma, liver and bile concentrations were determined by HPLC 0.5 h, 2 h and 4 h after administration. Following stomach-, duodenum- and ileum-specific delivery of oxymatrine to the rats, both oxymatrine and matrine were found in the gastrointestinal wall, the contents, plasma, liver and bile. M was mostly found in the liver, while OM was mainly excreted in the bile. The quantity of OM in bile was higher than that in plasma and liver, indicating that hepatic uptake and bile excretion may be via active transport. In conclusion, there is significant first-pass metabolism and entero-hepatic circulation of oxymatrine in rats.

Key words: Oxymatrine, Matrine, Gastrointestinal tract, Absorption, First pass metabolism, Excretion of bile