ABSTRACT
<p><b>OBJECTIVE</b>Studying the metabolic pharmacokinetic of baicalin of Qingkailing injection in rat, to search for effector substance of Qingkailing injection in vivo.</p><p><b>METHOD</b>Qingkailing sterile injection powder was given by caudal vein, then blood, liver and lung were collected in various time, the concentration of baicalin from samples were determined by HPLC-MS. Pharmacokinetic evaluation was carried out using the 3P87.</p><p><b>RESULT</b>After Qingkailing injection, Baicalin was consistent with two-compartment model in rat. 45 min, the concentration of baicalin in hepatic tissue reached maximum, followeded by decrease sharply, 120 min began to rise slowly, present double hump phenomenon. In lung, baicalin concentration was far more than in liver, was eliminated more slowly, but they have the same t(max).</p><p><b>CONCLUSION</b>After Qingkailing injection, baicalin distributed quickly to liver and lung, baicalin is one of effector substance of qingkailing injection in vivo. Baicalin might have hepatoenteral circulation.</p>