IDEBENONE LOADED LIPID NANOPARTICLES: EVALUATION OF IN VITRO ANTIOXIDANT ACTIVITY AND IN VIVO TOPICAL EFFECTS

Idebenone (IDE), a synthetic analogue of coenzyme CoQ10, is an antioxidant agent that has been proposed for the treatment of skin disorders, including skin ageing. Due to its high lipophilicity, IDE is a poor skin permeants and it could benefits of being incorporated in suitable drug delivery systems to improve its topical bioavailability. Recently, solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) have emerged as promising carriers for topical drug delivery, owing to their many advantages compared to conventional formulations. The aim of this work was to assess IDE-loaded SLN and NLC in vitro antioxidant activity and in vivo effects after topical application in human volunteers. These nano-carriers were prepared by the phase inversion temperature method and showed spherical shape, small particle sizes (25-40 nm), polydispersity indices < 0.300 and good stability. In vitro antioxidant assays (DPPH and reducing power method) revealed a greater antioxidant activity of IDE-loaded SLN compared to IDE-loaded NLC, at both IDE concentrations investigated (1.0% and 1.5% w/w). In vitro experiments on fibroblast cells HS-68 showed that treating cells with IDE-loaded lipid nanoparticles (SLN and NLC), before the exposure to UV light, resulted in a significant protection of cells from oxidative stress. After a two-week topical application of gel vehicles containing IDE loaded SLN or NLC on healthy human volunteers, an increase of skin hydration was observed in comparison with control gel. These results suggest that loading IDE into SLN or NLC could be regarded a promising strategy to improve its topical effectiveness.