Amphotericin B-Loaded Nanostructured Lipid Carrier Gel: Preparation and Evaluation for Enhanced Skin Permeation

Amphotericin B (BCS Class IV), an effective treatment for cutaneous leishmaniasis, has limited topical application due to poor skin penetration and stability. To overcome these challenges, this study aimed to formulate Amphotericin B-loaded nanostructured lipid carrier (NLC) gel to enhance drug encapsulation, stability, and controlled release. Amphotericin B-loaded NLCs were synthesized using a microwave-assisted method, which improved encapsulation efficiency and controlled particle size. The NLC dispersion was then incorporated into Carbopol 934 to form a gel. Characterization included particle size, zeta potential, morphology, spreadability, extrudability, in vitro drug release, ex-vivo skin permeation, and histopathological evaluation. The NLCs had a particle size of 180 nm, a polydispersity index of 0.32, and a zeta potential of –28.8 mV, ensuring stability. The Amphotericin B-NLC gel exhibited favorable physicochemical properties, including a smooth texture, a pH of 6.3, extrudability (9.5 ± 0.12 gm/cm²), and spreadability (6.4 cm). In vitro release studies demonstrated sustained release, with 48.05% drug release after 8 hours. The release kinetics followed the Higuchi model, indicating Fickian diffusion as the release mechanism. Ex-vivo permeation studies showed significantly enhanced skin permeation with the NLC and NLC gel formulations compared to the aqueous dispersion. Histopathological analysis indicated no signs of toxicity, with preserved skin integrity. The Amphotericin B-NLC gel formulation may significantly improve drug delivery for treating cutaneous leishmaniasis by enhancing skin penetration, providing controlled release, and demonstrating excellent safety.