Amphotericin B liposomal formulation: applicable preparation methods, challenges, and tips

Abstract

Objective This study was intended to explore and evaluate the appropriate methods for preparation of Amphotericin B (AmB) liposomes with acceptable characteristics. Significance This project provides pre-formulations for industrial manufacturing of liposomal AmB which confers improved properties, besides reduced toxicity compared with the plain drug. Methods At first, Solubility screening tests were performed, and in the following, three liposome preparation methods including ethanol injection, solvent evaporation, and solvent-free method were examined. In the following, the physicochemical characteristics of the prepared liposomes as well as size, size distribution, zeta potential (ZP), morphology, drug loading, loading capacity, physicochemical stability, and drug-lipid interaction studies were investigated. HPLC was applied for analyzing AmB. Results In all three methods, liposomes with acceptable characteristics were obtained. The size range of liposomes was 150.3 to 263.9 nm and polydispersity index ≤0.32. In morphologic evaluations, the liposomes have appeared as spherical and separate vesicles. A physical loading of AmB without specific interaction between components was achieved. The lyophilized powder in the solvent-free method was physicochemically stable for 6 months without changes in appearance; the remaining drug after 6-month storage at 25 °C and 60% RH, accounts for 91.5 ± 0.5% compared with the initial drug loaded in liposomes, and degradation pattern follows a linear order. Conclusion As a result, AmB-loaded liposomes were prepared in three applicable methods. The solvent-free method can be considered the most economical and environmental-friendly.