The effect of polymer–surfactant emulsifying agent on the formation and stability of α-lipoic acid loaded nanostructured lipid carriers (NLC)

α-Lipoic acid loaded nanostructured lipid carriers (ALA-NLC) were developed by high pressure homogenization (HPH) technology. The effects of polymer-surfactant emulsifying agents on the formation and stability of ALA-NLC were characterized by dynamic light scattering (DLS), rheological analysis, wide angle X-ray diffraction (WAXD), and high efficiency liquid chromatography (HPLC). The particles size, viscoelastic property and stability of ALA-NLC samples were significantly influenced by polymer–surfactant emulsifying agents. Polymer is considered as a primary emulsifying agent in ALA-NLC. Surfactants, which have small and flexible hydrophilic head group, would have strong interaction with polymer, and form strong interfacial film, thus could improve the stability of ALA-NLC. These results will be productive for better understanding of the preparation and stability of NLC, and two formulations applied here may have some potential applications for α-lipoic acid dietary supplement or nutri-cosmetics.