Permeation of topically applied caffeine from a food by-product in cosmetic formulations: Is nanoscale in vitro approach an option?

The aim of the present work was to develop and evaluate the potential of nanostructured lipid carriers associated with caffeine extracted from Coffee Silverskin (NLC-CS), a food by-product, as a new possible topical therapy of cellulitis. Caffeine gain increasing research interest due to their cosmetic potential, particularly in gynoid lipodystrophy, commonly known as cellulite. NLC-CS were prepared via double emulsion technique using polysorbate 60 as surfactant and characterized for their morphology, particle size, zeta potential, association encapsulation and stability. The in vitro skin permeation studies were performed on Franz diffusion cells using pig skin ear as permeation membrane and the optimized formulation was compared with a hydroalcoholic solution of Coffee silverskin (CS) extract. NLC-CS were within the nanosized range (≈200nm), with a low polydispersity index (<0.25) and zeta potential values around -30Mv, presenting storage stability up to 180days at 25°C/65% relative humidity (RH) and 40°C/75% RH. The association efficiency (AE) of caffeine was about 30% at production time and after storage period. Cryo-SEM images confirmed the spherical shape of NLC-CS. The in vitro skin permeation study demonstrated that NLC-CS had a similar skin permeation profile when compared to caffeine in CS extract.