Protective Effect of Liposomal-Amphotericin B Against C. Albicans Infection in Mice

The efficacy of free amphotericin B (AmpB) and liposomal-amphotericin B (L— AmpB) in the protection against C. albicans infection in mice was studied. Mice injected with a single dose of L-AmpB (1-4 mg/kg) two days prior to the yeast inoculation had an increased survival time when compared to animals injected with lower doses (0.8 mg/kg) of free AmpB or L-AmpB. L-AmpB (4 mg/kg of body weight) conferred protection against the fungal infection even when administered as a single dose five days prior to the yeast inoculation. A single-dose regimen of free AmpB showed a protective effect only when administered two days prior to the inoculum. When mice were challenged with larger yeast inocula, protection was seen with L-AmpB (4 mg/kg) or with multiple doses of free AmpB (0.8 mg/kg daily x 5) and not with single doses of free AmpB. In this group of mice, only animals treated with L-AmpB were microbiologically free of infection.