[The kinetics of accumulation and elimination of the antitumor preparation tomizine-35 S].

On rats with sarcoma M-1 the peculiarities of accumulation and elimination of the folic acid antagonist-pyrimido (4,5-b), (1,4) thiazinon-35S, called "thomizine", have been studied. In travenous injection of thomizine-35S with the activity of 5 muc per animal the highest initial concentration of radioactivity was observed 5-15 minutes after the injection. While decreasing, the radioactivity absorption coefficients in organs were distributed as follows: the kidneys, pancreas, organs of the endocrinous system, lymph nodes, the stomach, liver, small intestine, brain. Thomizine-35S accumulation in rat organs proceeded not only on account of its intake with blood but also due to penetration and subsequent deposition in structural tissue elements. Lessening of radioactivity in the organism of rats was dependent exponentially. Elimination of the drug was realized mainly via the kidneys. 89 per cent of the absorbed radioactivity was eliminated from the organism with a period of semielimination of 1 hour, 11 per cent - with a period of semielimination of 36 hours.