天钩降压胶囊中黄芩苷大鼠在体肠吸收研究

目的:研究天钩降压胶囊中黄芩苷在大鼠肠道的吸收动力学及不同肠段、pH、药物浓度、P-gp抑制剂对吸收的影响.方法:采用大鼠在体肠灌流试验,用HPLC测定不同时间点样品中黄芩苷的含量,用紫外-可见分光光度法测定不同时间点样品中酚红的含量.结果:在pH 5.0,6.5,7.4时不影响黄芩苷的吸收;P-gp抑制剂维拉帕米可增加黄芩苷的吸收;在供试液质量浓度5～ 20 mg·L-1,黄芩苷吸收量线性增加;吸收动力学方程为Y=-0.073 7X+0.118 7(r=0.994 8),Ka 0.073 7 h-1,t1/29.40 h.结论:黄芩苷主要在结肠吸收,呈一级动力学过程,吸收机制为被动扩散;黄芩苷为P-糖蛋白的底物.

Study on in situ intestinal absorption of baicalin contained in Tiangou Jiangya capsules

Objective: To study in situ intestinal absorption kinetics of baicalin contained in Tiangou Jiangya capsules, and the effect of different intestinal segments, pH value, drug concentration and P-gp inhibitor on the absorption. Method: The in situ intestinal perfusion test was adopted, and HPLC method was used to determine the content of baicalin in samples at different time points. Ultra-violet (UV) spectrophotometry was used to determine the content of phenol red in samples at different time points. Result: When pH value was at 5.0, 6.5, 7.4, the absorption of baicalin was not impacted. P-gp inhibitor verapamil could enhance the absorption of baicalin. When the quality concentration of the test solution ranged between 5-20 g·L^-1, the linearity of the absorption amount of baicalin increased. The absorption kinetic equation of baicalin was Y=-0.073 7X+0.118 7 (r=0.994 8), K_a 0.073 7 h^-1, t_1/2 9.40 h. Conclusion: Baicalin is mainly absorbed in colon. The absorption of baicalin shows the first-order kinetics process, with the absorption mechanism of passive diffusion. Baicalin is a substrate for P-gp.