Despite significant antileishmanial activity of
amphotericin B (AmB) in vitro, the use of the
deoxycholate formulation (
Fungizone) is limited because of serious side effects.
Lipid formulations of AmB have been proposed to reduce this toxicity. We compared the tolerance and efficacy of the conventional AmB prepared with
deoxycholate, AmB emulsified in
Intralipid 20%,
amphotericin B lipid complex (
Abelcet), and liposomal AmB (
AmBisome) in a murine model of
visceral leishmaniasis induced by Leishmania infantum. Control groups included untreated mice and mice treated with the pentavalent antimonial (
Glucan-time). Balb/C mice were infected intravenously on day 0 with 10(7) promastigotes of L. infantum, then treated from days 7 to 17 (early treatment group) or from days 60 to 70 (
delayed treatment group).
Glucan-time was administered daily by
intraperitoneal injection, whereas AmB formulations were administered intravenously on alternate days. On days 20, 60 and 120 in the early treatment group and 72 and 125 in the
delayed treatment group, parasite burdens were determined in liver, spleen, and lungs by subculturing using a microtitration method.
Abelcet (12 mg/kg) and
AmBisome (12 mg/kg) completely eradicated the parasites from the tissues. Both of these
lipid formulations enabled higher dosages to be tolerated, and were remarkably more effective than
Fungizone (0.8 mg/kg) and AmB diluted in
Intralipid 20% (1.2 mg/kg) in the treatment of murine
visceral leishmaniasis due to L. infantum.