Preparation and characterization of silybin-loaded nanostructured lipid carriers

Nanostructured lipid carriers (NLC) are a new generation of lipid nanoparticles, which are produced by controlled mixing of solid lipids with spatially incompatible liquid lipids leading to special nanostructures with improved drug incorporation and release properties. In this study, silybin-loaded nanostructured lipid carriers with various liquid lipid content were successfully prepared by the method of emulsion evaporation at a high temperature and solidification at a low temperature. The size and morphology of nanoparticles were significantly influenced by the liquid lipid content. As the liquid lipid content increased to 20 wt%, the obtained particles showed distinguished smaller size. Compared with solid lipid nanoparticles (SLN), NLC presented improved drug loading capacity which increased with increasing the liquid lipid content. The differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis indicated that the incorporation of liquid lipids could interfere with the crystallization of solid lipids. The drug in vitro release behavior from NLC displayed a biphasic drug release pattern with burst release at the initial stage and prolonged release afterwards, and the successful controlled release rate can be achieved by controlling the liquid lipid content.