目的：研究白术内酯I在大鼠各肠段的吸收动力学特征。方法：采用大鼠在体肠循环模型和高效液相色谱法研究白术内酯I在大鼠各肠段的吸收特性。结果：白术内酯I在大鼠十二指肠、空肠、回肠和结肠的吸收速度常数没有显著性差异，加入P-糖蛋白抑制剂维拉帕米和地高辛后，都能显著提高白术内酯I的吸收速度常数。结论：白术内酯I属于高渗透性药物，其在大鼠小肠的转运机制为被动扩散，无特殊的吸收窗，P-糖蛋白介导了白术内酯Ｉ的小肠吸收。
Objective: To investigate the absorption kinetics of atractylenolide I in intestines of rats and the influence of P-glycoprotein (P-gp) on the absorption. Method: The absorption kinetics was investigated using the method of in situ intestine absorption in rats and the samples were determined by HPLC. Result: Atractylenolide 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. Conclusion: Atractylenolide 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 segnents 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.