Physicochemical properties of amphotericin B liposomes prepared by reverse-phase evaporation method

Abstract

The physicochemical properties of phosphatidylcholine-cholesterol liposomes containing amphotericin B and prepared by reverse-phase evaporation method were studied. Uniformly dispersed liposomal suspensions were obtained by employing 3:1 ratio (by volume) of diethyl ether to normal saline, 5 min sonication time at 7°C, and evaporation of diethyl ether at 25°C. Microscopic examination showed that the prepared liposomes were spheroids with unilamellar, oligolamellar, or multilamellar structure. The liposomes containing amphotericin B 2.0 mol% of total lipid led to the highest percentage of drug entrapment. Liposomes with maximum entrapment efficiency were obtained from using 250 μmol of total lipid. The liposomal amphotericin B possessing the highest drug entrapment efficiency (approximately 95%) with particle size range of 1307-1451 nm was the one composed of 1:1 molar ratio of phosphatidylcholine to cholesterol.