Preparation and Characterization of Nanoparticles Based on Hydrophobic Alginate Derivative as Carriers for Sustained Release of Vitamin D3

Hydrophobic alginate derivative was prepared by modification of alginate by acid chloride reaction using oleoyl chloride without organic solvents. The conjugate of oleoyl alginate ester (OAE) was confirmed by FT-IR and (1)H NMR. The degree of substitution (DS) of OAE was determined by (1)H NMR, and it ranged from 0.84 to 3.85. In distilled water, OAE formed self-assembled nanoparticles at low concentrations in aqueous medium, and nanoparticles retained their structural integrity both in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The loading and release characteristics of nanoparticles based on OAE were investigated using vitamin D(3) as a model nutraceutical. As the concentration of vitamin D(3) increased, the loading capacity (LC) increased, whereas the loading efficiency (LE) decreased. Nanoparticles could release vitamin D(3) at a sustained rate in gastrointestinal fluid. These results revealed the potential of OAE nanoparticles as oral carriers for sustained release of vitamin D(3).