Impact of nanostructured lipid carriers on dapsone delivery to the skin: in vitro and in vivo studies

The main objective of this study was to develop, characterize and evaluate the potential use of dapsone-loaded nanostructured lipid carriers (NLCs) as a topical treatment for acne. Differently charged NLC formulations were successfully prepared using an emulsification/sonication method. The particle sizes ranged from 106.2 +/- 5.6 nm to 151.3 +/- 7.4 nm, and the NLCs possessed the predicted surface charges, depending on the emulsifier used (Tween 80, Transcutol P, or cetyltrimethylammonium bromide). The entrapment efficiencies ranged from 76.5 +/- 3.8% to 91.1 +/- 3.9%. Selected formulations were assessed for possible interactions, in vitro release, ex vivo skin permeation, pharmacological efficacy and safety compared with a hydroalcoholic solution. Dapsone was embedded in the lipid matrix of NLCs and behaved as controlled release system with a good occlusive effect. Dapsone-loaded cationic NLC formulation enhanced the skin permeation of dapsone, increase the amount of dapsone retained in the skin in controlled manner, and improved the anti-rosacea activity. Based on these encouraging results, cationic NLC represents a promising carrier for the safe topical delivery of dapsone.