pH-Responsive Emulsions with β‑Cyclodextrin/Vitamin E Assembled Shells for Controlled Delivery of Polyunsaturated Fatty Acids

Lipid-based delivery systems (LBDSs) are widely applied in pharmaceuticals and health care because of the increased bioavailability of lipophilic components when they are coadministered with high-fat meals. However, how to accurately control their in vivo release and stability is still challenging. Here, after introducing the simple esterification and coprecipitation, we created the dual-functional composite ODS-β-CD-VE by the coassembly of β-cyclodextrin (β-CD), octadecenyl succinic anhydride (ODSA), and vitamin E (VE). The resulting dual-functional particle presented a uniform sheetlike shape and nanometer size. In addition, its chemical structure was clarified in detail via nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Benefiting from the antioxygenation of VE, lipid oxidation in the ODS-β-CD-VE-stabilized Pickering emulsion was effectively inhibited. Meanwhile, pH-induced protonation/deprotonation of carboxyl groups guaranteed that the emulsions kept steady at pH ≤4 but were unsteady under neutral conditions. In this way, the lipids contained in the emulsion were protected from gastric juice and then digested and accurately released as n-3 polyunsaturated fatty acids (PUFA) in the simulated intestine environment. This strategy sheds some light on the rational and efficient construction of LBDSs for nutrient supplements and even pharmaceuticals in a living digestive tract.