A novel approach based on lipid nanoparticles (SLN®) for topical delivery of α-lipoic acid

Abstract

This study describes the development, preparation and characterization of solid lipid nanoparticles (SLN®) containing the novel anti-ageing substance α-lipoic acid. Lipoic acid is chemically labile, i.e. the degradation products possess an unpleasant odour. Therefore, the active was encapsulated in SLN. A lipid with low melting point (Softisan®601) was selected for preparation of active-loaded SLN after screening the solubility of α-lipoic acid in physicochemically different lipids. An entrapment efficiency of 90% (UV analysis) was obtained for all developed formulations using Miranol®Ultra C32 as emulsifying agent. Particle size stability was monitored during 3 months storing the samples at 20°C and at 4°C. Results of DSC analysis confirm that these systems are characterized by a solid-like behaviour, although with a very low crystallinity index.

Keywords: :

• Solid lipid nanoparticles (SLN)
• alpha lipoic acid
• anti-ageing
• cosmetics