Efficacy of liposome-intercalated amphotericin B in the treatment of systemic candidiasis in mice.

We developed a liposome-intercalated preparation of amphotericin B by using small, unilamellar vesicles 0.06 to 0.1 micron in diameter. In contrast to previously described liposomal preparations of amphotericin B, these vesicles have the advantage that they are small enough to be filter sterilized. We compared the efficacy of liposomal amphotericin B with that of the commercial drug given as an intravenous bolus every other day for 13 days (seven doses) in mice with disseminated candidiasis. Survival rates were similar for the two preparations at each dosage of amphotericin B; however, the highest survival rates occurred at dosages of liposomal amphotericin B which would be lethal to these animals if administered as the commercial drug. Viable colony counts of fungi in various organs, particularly the kidneys, tended to be lower with increasing dosage of the drug. However, some organisms persisted even after 13 days. These studies indicate that liposomal formulations of amphotericin B merit further investigation because of their improved therapeutic margins.