Development and evaluation of ligand(s) decorated lipid nanoparticles for macrophage-targeted delivery of Amphotericin B with simultaneous immunostimulation for improved therapeutic efficacy: a proof-of-concept study

The present research work was designed to deliver a promising antiparasitic drug, Amphotericin B (AmB), to macrophages using lipid nanoparticles (LNPs) decorated with immunostimulatory macrophage-targeting ligands, Mannose and Muramyl Dipeptide (MDP). Blank and drug-loaded LNPs were formulated using the solvent emulsification-evaporation method followed by probe sonication with particle sizes of 181.2 ± 11.3 and 215.6 ± 17.9 nm, respectively. The optimized LNPs were functionalized with mannose and MDP separately, and AmB was encapsulated in the mannose- and MDP-conjugated LNPs, i.e., Man-LNPs and MDP-LNPs, respectively. The % entrapment efficiency was found to be 90.56 ± 1.39%; 88.23 ± 1.80% and 93.29 ± 1.32%, whereas drug loading was observed to be 9.93 ± 0.26%; 9.06 ± 0.31% and 10.1 ± 0.19%, respectively, for AmB-LNPs, AmB-Man-LNPs, and AmB-MDP-LNPs. A sustained-release pattern was observed with all three formulations, with relatively faster release at pH 5.5 than at pH 1.2 and 7.4 in in vitro drug release studies. Stability studies indicated that developed formulations could be easily redispersed in DDW after 3 months of storage at 2–8 °C. The developed formulations were found to be safe in in vitro cytotoxicity and hemolytic toxicity studies. Cellular uptake studies using the macrophage cell line J774A.1 confirmed the macrophage-targeting potential of the developed ligand-decorated formulations. Finally, it can be concluded that AmB-Man-LNPs and AmB-MDP-LNPs may be further explored as promising alternatives for the targeted delivery of AmB to treat infectious diseases.