OBJECTIVETo investigate the absorption kinetics of atractylenolide I in intestines of rats and the influence of P-glycoprotein (P-gp) on the absorption.

METHODThe absorption kinetics was investigated using the method of in situ intestine absorption in rats and the samples were determined by HPLC.

RESULTAtractylenolide I is absorbed quite well at all segments of intestine in rats and no specific absorption was founded in different segment. When the concentration of perfusion solution was increased contrarily the absorption rate constant (Ka) kept at the same level. Compared Ka of three different concentration of perfusion solution with variance analysis method, Ka of atractylenolide I had no significant differences. But the Ka values were significently increased in the presence of P-gp inbibitor, verapamil or digoxin.

CONCLUSIONAtractylenolide I can be classified into high penetrating drug. Passive diffusion dominates the absorptive transport behivior of atractylenolide I. Atractylenolide I can be absorbed in the whole intestinal segments and there is not a preferntial absorption zone in the intestine. The absorption and secretion of atractylenolide I are mediated by the efflux transport system, P-gp.