Preparation and Characterization of Nanostructured Lipid Carriers for Improved Topical Drug Delivery: Evaluation in Cutaneous Leishmaniasis and Vaginal Candidiasis Animal Models.

The present study aimed to develop, characterize and evaluate the amphotericin B-loaded nanostructured lipid carriers (AmB-NLCs) for topical treatment of cutaneous leishmaniasis (CL) and vulvovaginal candidiasis (VVC). AmB-NLCs were characterized for particle size, zeta potential, encapsulation efficiency and surface morphology. Prepared NLCs were also characterized for in vitro drug release, ex vivo skin permeation and deposition before evaluating their in vitro and in vivo efficacy. Cytotoxicity of NLCs was assessed on MRC-5 cells, whereas skin irritation potential was evaluated in vivo using rats. Significant accumulation of drug in to the skin supported the topical application potential of drug-loaded NLCs. Encapsulation of AmB in NLCs resulted in enhanced in vitro potency against promastigotes and intracellular amastigotes of L. major JISH 118 (IC50 ± SEM = 0.02 ± 0.1 μM for both) compared with free drug (IC50 ± SEM = 0.15 ± 0.2 & 0.14 ± 0.0, respectively). Similar improved potency of AmB-NLCs was also observed for other Leishmania and fungal strains compared with drug solution. Topical application of AmB-NLCs on L. major-infected BALB/c mice caused a significant reduction in parasite burden per mg of lesion (65 × 108 ± 13) compared with the control group (> 167.8 × 108 ± 11). Topical AmB-NLCs gel demonstrated superior efficacy in the vaginal C. albicans rat model for VVC as compared with plain AmB gel. Moreover, results of in vitro cytotoxicity assay and in vivo skin irritation test confirmed AmB-NLCs to be non-toxic and safe for topical use. In conclusion, NLCs may have promising potential as carrier for topical treatment of various conditions of skin and mucosa.