[The search for new antiparasitic agents. 17. The synthesis and study of the anti-echinococcal activity of the new preparation G-1697].

The paper describes the synthesis of the new agent G-1697 which is 4-[(benzo-2,1,3-thiadiazolyl-4)amino]-5, 6,7,8-tetrahydrobenzothieno [2,3-d] pyrimidine and the results of testing its acute toxicity and antiparasitic activity on a model of Echinococcus multilocularis invasion at the larval stage in cotton rats. The maximum nonlethal dose of G-1697 was 4.0 g/kg for outbred mice of both sexes whose weight was 14-16 g. Adult cotton rats (males) received the agent with their feed in increasing daily doses for 3 weeks continuously on days 8 to 28 after infection. The daily dose of its active ingredient varied from 0.03 to 0.35 g/kg and averaged 0.12 g/kg (the mean total dose per session was 2.47 g/kg). The baseline weight of parasitic larvocysts (PL) per animal averaged 0.28 g at the baseline. In the treated and control rats sacrificed 34 days following infection, the mean mass of PL per animal was 0.95 and 7.51 g, respectively. In the cotton rats treated with G-1697, the suppressed growth index calculated by three parameters (moderate, maximum, and minimum mass of PL in the animals of the comparable groups after treatment with regard to the similar baseline variables) was 90.8, 91.0 and 92.7, respectively, versus the controls. Among all PL found in each animal, its death was approximately 70-90% in the treated rats.