Abstract.

In vitro studies against epimastigotes and intracellular amastigotes and in vivo studies in inbred C3H/He mice infected with Trypanosoma cruzi Brazil strain were performed to determine the activities of two N-substituted imidazole compounds, RS- 49676 and ketoconazole. Both compounds are extremely active in vitro against the amastigotes (ED50 <0.0001 μg/ml) yet inactive against the epimastigotes. In vivo, RS-49676 increased the mean survival time over 11 weeks beyond the untreated control when given subcutaneously twice daily at 100 mg/kg/day. Ketoconazole increased the mean survival time 11-18 days beyond the untreated control (mean survival time 22 days) when given subcutaneously twice daily at 100 mg/kg or orally once daily at 100 mg/kg. Approximately 20%-25% of the RS-49676 treated mice were cured as determined by culturing the blood of infected mice with fibroblast lung cells. None of the ketoconazole mice were cured.