An Organic Antimony Compound with Curative and Prophylactic Activity in Experimental Trypanosomiasis

Abstract

A new organic heterocyclic penta-valent Sb compound has been synthesized: polymerized Na p-(2,4-diamino-l,3,5-triazinyl-6-amino)-phenylstibonate. All of 56 mice tolerated a single intraperit. dose of 2.5 g./kg. A single intraperit. dose of 0.0125 g./kg. cured all of 34 mice with Trypanosoma equiperdum infection, lethal to all 10 untreated control mice. The therapeutic index is thus 200. There is also a strong prophylactic effect in exptl. trypanosomiasis: a single intraperit. dose of 0.050 g./kg. protected after 69 days 5 of 5 mice against an infection with virulent T. equiperdum. 105 mice were treated with a single intraperit. dose of 0.3 g./kg. One month later the animals were given a T. equiperdum infection, repeated at weekly intervals on surviving mice found to be free of trypanosomes. Untreated controls set up at each infection die without exception in 3-5 days. 50 days after the single treatment, 100% of the pretreated animals were protected (4 test infections); after 85 days 95% were protected (9 test infections); after 99 days 57% (11 test infections); after 135 days 15% (16 test infections); after 155 days 6% (18 test infections). The mechanism of the prophylactic activity is based on the chemical effect of the drug, which is absorbed and eliminated so slowly that a sufficient trypanocidal conc. is maintained in the organism over a considerable length of time.