ABSTRACT
<p><b>OBJECTIVE</b>To study the process in vivo of the components in the precipitation of Xiexin decoction.</p><p><b>METHOD</b>The components in the rats' urine samples after oral administration of baicalin, single herb decoction of Radix Scutellariae or the precipitation of Xiexin decoction were analyzed by LC-MS-MS method; and the absorption of baicalin in different samples were calculated by intestinal in situ loop method.</p><p><b>RESULT</b>The urinary excretion amounts of baicalin in three samples were not obviously different, whereas the time reach elimination-peak of baicalin in them had significant difference. The absorption of baicalin in the precipitation was obviously greater than that in the single herb decoction and single baicalin. We found that wogonoside and 7-O-glucuronide chrysin were the metabolites presenting in the rat urine samples after oral administration of baicalin by LC-MS-MS, which had never been reported.</p><p><b>CONCLUSION</b>The resident time in the body of baicalin in the precipitation is prolonged, compared with that in the single herb decoction and single baicalin. The metabolites may be the potential biological components in vivo of baicalin in the precipitation.</p>