Enhanced antifungal effects of amphotericin B-TPGS-b-(PCL-ran-PGA) nanoparticles in vitro and in vivo

Background: Amphotericin B (AMB) is a polyene antibiotic with broad spectrum antifungal activity, but its clinical toxicities and poor solubility limit the wide application of AMB in clinical practice. Recently, new drug-loaded nanoparticles (NPs) - diblock copolymer D-alpha-tocopheryl polyethylene glycol 1000 succinate-b-poly(epsilon-caprolactone-ran-glycolide) (PLGA-TPGS) - have received special attention for their reduced toxicity, and increased effectiveness of drug has also been reported. This study aimed to develop AMB-loaded PLGA-TPGS nanoparticles (AMB-NPs) and evaluate their antifungal effects in vitro and in vivo. Methods: AMB-NPs were prepared with a modified nanoprecipitation method and then characterized in terms of physical characteristics, in vitro drug release, stability, drug-encapsulation efficiency, and toxicity. Finally, the antifungal activity of AMB-NPs was investigated in vitro and in vivo. Results: AMB-NPs were stable and spherical, with an average size of around 110 nm; the entrapment efficacy was closed to 85%, and their release exhibited a typically biphasic pattern. The actual minimum inhibitory concentration of AMB-NPs against Candida albicans was significantly lower than that of free AMB, and AMB-NPs were less toxic on blood cells. In vivo experiments indicated that AMB-NPs achieved significantly better and prolonged antifungal effects when compared with free AMB. Conclusion: The AMB-PLGA-TPGS NP system significantly improves the AMB bioavailability by improving its antifungal activities and reducing its toxicity, and thus, these NPs may become a good drug carrier for antifungal treatment.