In vitro and in vivo activity of amphotericin B-lipid formulations againstexperimental Trypanosoma cruzi infections

The activities of four amphotericin B formulations, Fungizone(R), AmBisome( R), Amphocil(TM), and Abelcet(R), were compared in vitro and in vivo agains t Trypanosoma cruzi infections. In vitro, Fungizone and Amphocil were highl y active against T. cruzi Y strain amastigotes in macrophages with 50% effe ctive dose (ED50) values of 0.027-0.028 mu g/ml, which were 7-fold and 42-f old more active than AmBisome and Abelcet, respectively. In vitro activitie s of all formulations against T. cruzi amastigotes in Vero cells were simil ar, with ED50 values in the range of 2.0-4.2 mu g/ml. Acute infections of t he T. cruzi Y strain in BALB/c mice were suppressed in all animals by a sin gle 25 mg/kg dose of the liposomal formulation AmBisome. At the same dose, the two other lipid formulations, Amphocil and Abelcet, increased the survi val rate but did not suppress infection in all animals.