Lipid-based microtubes for topical delivery of Amphotericin B

The self-assembly process is a valuable tool for constructing nano and microstructures. Microtubes (MTs) self-assembled from amphiphiles are novel promising nanomaterials as they have easy self-assembly in aqueous solutions, reproducibility and biocompatibility. The incorporation of amphotericin B (AmB) into lipid microtubes formed from 12-hydroxystearic acid (12HSA) when mixed with ethanolamine in aqueous media was investigated. MTs of several concentrations of lipid material and AmB were prepared. The structure was characterized by phase-contrast microscopy, TEM and SEM. The type of interaction was analyzed by FTIR and DSC. Stability studies were carried out at room temperature and at 4 °C. Loading efficiency of the system was found to be much higher than the drug solubility in water. MTs with 1% of 12HSA and 1 mg/ml of AmB showed to be the most stable formulation. In vitro skin penetration assay showed a flux of 18.20 ± 3.35 μg/cm2. Amb-loaded MTs in vitro antifungal activity was evaluated and formulation showed similar results to that of AmB deoxycholate showing that AmB retained its antifungal activity in the MTs formulation.

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► AmB incorporation into 12- hydroxystearic acid microtubes was investigated.
► AmB interaction with lipid material was studied by DSC and FTIR.
► AmB loading into microtubes was thousands times higher than drug solubility in water.
► Drug was tested for antifungal activity against several cultures and species.
► AmB loaded into microtubes penetrated the skin 3.05 ± 0.05 μg/cm2/h.