Comparison of the leishmanicidal activity of fungizone, liposomal AmB and amphotericin B incorporated into egg lecithin-bile salt mixed micelles.

We compared leishmanicidal activity of five formulations of amphotericin B (AmB). AmB used as Fungizone immediately caused cell lysis, at lower concentrations partial, and at higher concentrations total; the non-lysed cells reassuming growth. AmB formulated with egg-lecithin and bile salt at doses equivalent to those of Fungizone was not active, whereas at higher doses it resulted in a delayed but complete inhibition of cell growth. The activity of liposomal AmB was comparable to that of Fungizone. The time of initial leishmanicidal activity of the five formulations tested can be ascribed to the rate of free, monomeric AmB delivered. Features that are characteristic of the anticellular effect of AmB formulated with egg lecithin and bile salts, a delay in activity, a requirement for higher concentration and total inhibition of cell growth, were also noted.