Visceral leishmaniasis in the BALB/c mouse: antimony tissue disposition and parasite suppression after the administration of free stibogluconate.

BALB/c mice with an acute or chronic Leishmania donovani infection were treated with intravenous sodium stibogluconate solution and the parasite suppressions determined in the spleen, liver and femur bone marrow. Antimony concentrations in these and other tissues were determined by hydride generation-atomic absorption spectrophotometry. There was little correlation between tissue antimony levels one hour after treatment and drug efficacy. It would appear that the peak tissue antimony concentration achieved soon after dosing, rather than the lower concentrations which are readily sustained in most tissues, is the most important factor in the antileishmanial activity of stibogluconate. A high peak antimony concentration occurred in the liver, where parasites were significantly suppressed, and was not observed in the two other sites of infection, where the parasites were apparently less susceptible to stibogluconate therapy.