Pentavalent antimony-mannan conjugate therapy of experimental visceral leishmaniasis.

Pentavalent antimony-mannan (Sb[V]-mannan) was 10-fold more potent than sodium stibogluconate in a murine model of visceral leishmaniasis. Liver antimony concentrations were six-fold higher after Sb[V]-mannan therapy compared with a dose of sodium stibogluconate that was equipotent in reducing liver parasite burdens. Murine toxicity of Sb[V]-mannan was variable, with a 50% lethal dose (LD50) for one preparation that was well above the concentration that killed 90% of the parasites, and for another preparation was only modestly higher than the concentration that killed 90% of the parasites.