Du Xian-hua, Niu Xin, Feng Qian-jin, Du Hong, Li Hai-yan
Beijing University of Chinese Medicine, Beijing 100029, China.
Zhongguo Zhong Yao Za Zhi. 2008 Jun;33(12):1406-9.
To investigate the absorption mechanism of genistein self-microemulsifying system in rat intestines.
The concentrations of phenol red and genistein by in situ perfusion in rats were determined by UV and HPLC, respectively. The effects of drug concentrations, pH, various intestinal segments and P-glycoprotein (P-gp) inhibitor verapamil on the absorption had been studied.
The absorption rate constant (Ka) of genistein had no significant difference at concentrations of 0.05-0.5 mg x mL(-1) and pH of 5.4-7.8 in perfusion. It was Ka of jejunum > ileum > duodenum > colon. The absorption of genistein in jejunum had significant difference (P < 0.05) compared with other parts of intestines. Ka was increased obviously when verapamil was coper-fused with genistein (P < 0. 05).
The absorption of genistein self-microemulsifying system is a first order process with passive diffusion mechanism related to P-gp efflux. It can be absorbed at all segments of rat intestine, and the jejunum is the best absorption segment, pH had no special effect on the absorption of genistein self-microemulsifying system in rat intestine.
研究染料木黄酮自微乳化系统在大鼠肠道内的吸收机制。
分别采用紫外分光光度法和高效液相色谱法测定大鼠原位灌注时酚红和染料木黄酮的浓度。研究了药物浓度、pH值、不同肠段以及P-糖蛋白（P-gp）抑制剂维拉帕米对吸收的影响。
灌注时染料木黄酮在浓度为0.05 - 0.5mg·mL⁻¹、pH值为5.4 - 7.8时吸收速率常数（Ka）无显著差异。各肠段Ka值大小为：空肠＞回肠＞十二指肠＞结肠。染料木黄酮在空肠的吸收与肠道其他部位相比有显著差异（P＜0.05）。维拉帕米与染料木黄酮合用时Ka值明显升高（P＜0.05）。
染料木黄酮自微乳化系统的吸收是一级过程，其机制为与P-gp外排相关的被动扩散。它能在大鼠肠道各段被吸收，空肠是最佳吸收段，pH值对染料木黄酮自微乳化系统在大鼠肠道内的吸收无特殊影响。
