Evaluation of different exposure systems for the analysis of curcumin and coumarin in encapsulated in natural lipid nanocarriers

Nanostructured lipid carriers (NLC) is a promising type of vehicle that can improve drug stability and skin penetration. They can be topically applied, instillated in oral mucosa or used for pulmonary delivery; however, in vitro methods or even animal models do not reproduce real human exposure conditions. This way, this study evaluated the differences between the use of NLC containing coumarin and curcumin applied topically and nebulized by the exposure system (Vitrocell® Cloud) on ex vivo porcine ear skin. The skin distribution and penetration were evaluated by reflectance confocal microscopy (VivaScope 1500 ®) and laser scanning confocal microscopy (Leica TCS SP8®). Both methods presented similar results, being coumarin more reflective, fluorescent than curcumin in both exposure conditions. The nebulization system made the substances deposition more homogeneous but in lower concentrations on the skin surface; while their topical application showed higher concentrations that were mainly accumulated on the skin furrows.