Preparation of pH-sensitive chitosan-deoxycholic acid-sodium alginate nanoparticles loaded with ginsenoside Rb and its controlled release mechanism.

Ginsenoside is a natural extract of the genus ginseng, which has tumor preventive and inhibiting effects. In this study, ginsenoside loaded nanoparticles were prepared by an ionic cross-linking method with sodium alginate to enable a sustained slow release effect of ginsenoside Rb in the intestinal fluid through an intelligent response. Chitosan grafted hydrophobic group deoxycholic acid was used to synthesize CS-DA, providing loading space for hydrophobic Rb. Scanning electron microscopy (SEM) showed that the nanoparticles was spherical with smooth surfaces. The encapsulation rate of Rb enhanced with the increase of sodium alginate concentration and could reach to 76.62 ± 1.78 % when concentration was 3.6 mg/mL. It was found that the release process of CDA-NPs was most consistent with the primary kinetic model which is a diffusion-controlled release mechanism. CDA-NPs exhibited good pH sensitivity and controlled release properties in buffer solutions of different pH's at 1.2 and 6.8. The cumulative release of Rbfrom CDA-NPs in simulated gastric fluid was <20 % within 2 h, while could release completely around 24 h in the simulated gastrointestinal fluid release system. It was demonstrated that CDA-NPs can effectively control release and intelligently deliver ginsenoside Rb, which is a promising alternative way for oral delivery.