New thiadiazine derivatives with activity against Trypanosoma cruzi amastigotes

The cytotoxicity of 18 new 1,2,6-thiadiazin-3,5-dione 1,1-dioxides was eval uated. This group of products was previously assayed against epimastigotes of Trypanosoma cruzi and some of them showed a high antiprotozoal activity. Thereafter 13 compounds with a high anti-epimastigote activity and low cyt otoxicity were selected to be assayed against amastigotes. Some of the prod ucts showed the same or even lower cytotoxicity than nifurtimox and benznid azole, but most of them were very toxic for macrophages at 100 mug/ml. Only one of the compounds had an anti-amastigote activity similar to that of re ference drugs at 10 mug/ml, but unfortunately this disappeared at lower con centrations.