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[Study on in situ intestinal absorption of baicalin contained in Tiangou Jiangya capsules]
Ling-Jun Li1, Ji Li, Hua-Wei Lou
1School of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, China. lljun66@yahoo.com.cn
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. 0. 073 7 h -1 , t1/2 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.
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