liposomal amphotericin B (NeXstar Pharmaceuticals)

Liposomal amphotericin B is a lipid formulation of amphotericin B, designed to reduce the toxicity associated with conventional amphotericin B while maintaining or improving efficacy. It's composed of amphotericin B complexed with hydrogenated soy phosphatidylcholine, distearoylphosphatidylglycerol, and cholesterol, forming unilamellar lipid vesicles. ## Pharmacological Properties L-AmB has several advantages over conventional amphotericin B: - Higher plasma concentrations and longer circulation time - Slower uptake by the reticuloendothelial system - High concentrations in brain tissue - Biphasic elimination pattern from serum - Significantly reduced nephrotoxicity The mechanism of action remains the same as conventional amphotericin B, binding to ergosterol in fungal cell membranes, creating pores that lead to cell death. The liposomal formulation is disrupted when it binds to fungal cell walls but remains intact when exposed to mammalian cell membranes, explaining its reduced toxicity profile. ## Clinical Applications L-AmB is used to treat various conditions: - Serious fungal infections including mucormycosis, aspergillosis, blastomycosis, candidiasis, coccidioidomycosis, and cryptococcosis - Visceral leishmaniasis (kala azar) - Cryptococcal meningitis, particularly in immunocompromised patients - Mucormycosis (black fungus), which saw increased incidence during the COVID-19 pandemic - Empirical therapy in febrile neutropenia ## Access Challenges Despite its clinical importance, L-AmB faces significant access challenges: - High cost and limited availability in low- and middle-income countries - Gilead is the sole supplier of quality-assured L-AmB globally - Limited registration in countries where needed most - Supply shortages and distribution issues Médecins Sans Frontières (MSF) has advocated for improved access to this essential medication, highlighting the need for affordable pricing and consistent supply to treat neglected diseases in resource-limited settings.

Brand names

AmBisome