Retinoic acid loaded-nanostructured lipid carriers for acne treatment: development and clinical evaluation of skin safety

Retinoic acid (RA) is used in acne topical treatment. However, RA causes serious side effects. Lipid nanosystems, such as nanostructured lipid carriers (NLC), have the potential to reduce skin irritation. Therefore, the objective of this work was to develop a RA-loaded NLC formulation and evaluate skin irritation in humans using the market RA formulation as reference. NLC-RA were prepared by hot melt homogenization method and characterized by morphology, release profile and skin permeation (Franz diffusion cell). The skin irritation was evaluated in humans volunteers (CAAE 89452318.7.0000.5149) through the evaluation of transepidermal water loss (TEWL). NLC-RA developed showed spherical morphology, controlled release of RA, strong interaction with the epidermis and proved to be less irritant for topical use in the human studies in comparison to the market RA formulation. These results suggest that the NLC-RA represents a promising and safe alternative for the topical treatment of acne.