Nanostructured lipid carriers incorporated in alginate hydrogel: Enhanced stability and modified behavior in gastrointestinal tract

Abstract

The application of nanostructured lipid carriers (NLC) are influenced by their relatively poor stability, including storage stability and gastrointestinal stability. The aim of the present study was to develop NLC-hydrogel to improve the physical stability and modify the behavior of NLC in gastrointestinal tract. The quercetin-loaded NLC were successfully incorporated in alginate hydrogel beads using the extrusion dripping technique. Dynamic light scattering (DLS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were used to assess the influence of this incorporation on the feature of NLC, and results indicated that it had no obvious effect on the particle size, morphology, and inner structure of NLC. The incorporation of NLC in alginate hydrogel beads could effectively improve the physical stability of NLC compared with NLC dispersion and NLC-alginate sol. In vitro release study suggested that the quercetin release from NLC-alginate hydrogel beads was slower than that of NLC dispersion and NLC-alginate sol. In vitro digestion study revealed that only a small amount of incorporated NLC with a small size could diffuse into gastric fluid. Furthermore, because NLC diffused gradually from alginate hydrogel to intestinal fluid, the aggregation of NLC in intestinal fluid was prevented, and lipid matrix was gently hydrolyzed. These studies demonstrated that the incorporation of NLC in alginate hydrogel might be a promising method to improve the stability of NLC, modify the behavior of NLC in gastrointestinal tract, and control the release during digestion.