Amphotericin B 50 mg · Dry-powder injectables

Amphotericin B, the active ingredient of amphotericin B liposome for injection, acts by binding to the sterol component, ergosterol, of the cell membrane of susceptible fungi. It forms transmembrane channels leading to alterations in cell permeability through which monovalent ions (Na+, K+, H+, and Cl-) leak out of the cell resulting in cell death. While amphotericin B has a higher affinity for the ergosterol component of the fungal cell membrane, it can also bind to the cholesterol component of the mammalian cell leading to cytotoxicity. Amphotericin B liposome for injection, the liposomal preparation of amphotericin B, has been shown to penetrate the cell wall of both extracellular and intracellular forms of susceptible fungi.

The assay used to measure amphotericin B in the serum after administration of amphotericin B liposome for injection does not distinguish amphotericin B that is complexed with the phospholipids of amphotericin B liposome for injection from amphotericin B that is uncomplexed. The pharmacokinetic profile of amphotericin B after administration of amphotericin B liposome for injection is based upon total serum concentrations of amphotericin B. The pharmacokinetic profile of amphotericin B was determined in febrile neutropenic cancer and bone marrow transplant patients who received 1 to 2 hour infusions of 1 to 5 mg/kg/day amphotericin B liposome for injection for 3 to 20 days.

The pharmacokinetics of amphotericin B after administration of amphotericin B liposome for injection is nonlinear such that there is a greater than proportional increase in serum concentrations with an increase in dose from 1 to 5 mg/kg/day. The pharmacokinetic parameters of total amphotericin B (mean ± SD) after the first dose and at steady state are shown in the table below.