Distribution and metabolism of [3H] CMCa in S180 bearing mice

The blood radioactivity-time curve after iv [3H] CMCa in S180 bearing mice was found to be diexponential model. Pharmacokinetic parameters: t1/2 α = 9.6 min, t1/2 β = 37 h. It has quite rapidly distributed from the central compartment to the periperal compartment. The highest radioacitivity and the slowest metabolic rate were found in tumor. It further confirmed the foregoing result that this drug could concentrate in tumor, and was lower in brain with decreased neurotoxicity. The metabolic rates of the drug in blood and muscle were quite rapid, indicating it might be useful for clinical diagnosis and therapy of tumor. The results analyzed by TLC and scintillation counting of urine taken 24 h after iv [3H] CMCa to S180 bearing mice indicated that approximately 80% of urine total radioactivity was excreted as original drug in unchanged form and 7% as its hydrolyzate metronidazol. These results were similar to those in normal mice