Absorption Characteristics of Baicalin and Baicalein in Rat Small Intestine

OBJECTIVE To study the absorption characteristics of baicalin and baicalein. METHODS The model of in situ intestinal perfusion was used.A HPLC method was established to determine the drug concentration in the perfusate. RESULTS When the bile duct was not ligated, the absorption rate constant of baicalin and baicalein were (-0.004 7±0.013 4)h~ -1 and(0.496 0±0.051 2)h~ -1 , respectively; When the bile duct was ligated, the absorption rate constant of baicalin and baicalein were(0.023 9±0.026 2)h~ -1 and (0.210 6±0.073 5)h~ -1 , respectively. When baicalin or baicalein was perfused alone after the ligation of the bile duct,the concentrations of baicalein or baicalin were increased in the perfusate respectively. When baicalein was intravenous administered to rats after the ligation of the bile duct,baicalin were obtained in the perfusate.CONCLUSION Baicalin is more suitable to be administered orally than baicalin. Bile can not only excrete baicalin, but also evidently promote the absorption of baicalein. Baicalin is absorbed as baicalein formed by the intestinal bacteria, and then restored as its original form in the body.The part of the baicalin formed from the absorbed or intravenous administered baicalein can be excreted back into the gut.