Abstract

Lutein is a natural carotenoid with antioxidant properties, already proven in various topical applications. A 20% suspension of lutein in safflower oil (FloraGLO® Lutein) represents a good raw material for the production of creams and other semisolid formulations. However, the high viscosity of FloraGLO® and poor chemical stability of lutein in the suspension represents a practical limitation to its use. An efficient method was proposed in this study for taking benefit of the liquid oily composition of FloraGLO®, by realizing a nanostructured carrier system (NLC) able to ensure a controlled release of lutein and improve its permeability across the skin. NLC were prepared with different percentages of FloraGLO® as the liquid phase of NLC. The physical stability of NLC was assessed by storage at room conditions and by Turbiscan accelerated analysis. All the produced nanocarriers were perfectly tolerated after application on the skin. In an in vivo model of UV-induced skin erythema, the lutein-loaded NLC were able to improve the photo-protective effects of the antioxidant compared to the commercial suspension, when the NLC formulations were applied before inducing the erythema. This study also proved for the first time the possibility of converting a liquid formulation into a solid, modified release nanocarrier with more manageable formulative features.

Keywords: FloraGLO® Lutein, in vitro percutaneous permeation, in vivo skin permeation, in vivo tolerability, oily formulations, Turbiscan™, SLN, NLC, Photon Correlation Spectroscopy, Anti-Inflammatory Activity