抄録
Pharmacokinetic studies on metabolites pattern and their concentrations in the serum and tissues were performed in male rats after a single intravenous administration of 14C-CPT-11 at a dose of 10.62mg/kg using the HPLC method.
1. The unchanged drug, CPT-11, was detected as the main compound in the serum and tissues, and accounted for almost all the concentration of total radioactivity at early time after dose.
2. The concentrations of active metabolite, SN-38, in the serum and tissues were very low, but disappeared relatively more slowly than CPT-11. 3. The ratios of SN-38 AUC/CPT-11 AUC were 0.079 in the serum, 0.018 in the liver and intestinal tissue, and 0.004 in kidney, respectively. The relatively high concentration of SN-38 in the serum and liver must be ascribed to high esterase activity in these tissues, and that in the intestinal tissues could be ascribed not only to the esterase activity, but also to the biliary excretion of SN-38 and SN-38-glucuronide into intestine.
