Delivery of silybin using a zein-pullulan nanocomplex: Fabrication, characterization, in vitro release properties and antioxidant capacity

Abstract

Silybin (Sil) is a natural flavonoid that is mostly used clinically in the treatment of cirrhosis. However, its low water solubility and chemical instability hinder its practical application. In this study, zein-pullulan nanoparticles loaded with Sil (Sil@Pl-zeinNPs) were prepared by an anti-solvent precipitation method for the delivery of Sil, thereby improving its low water solubility and chemical instability with a view to expanding its clinical applications. By optimizing the preparation process of Sil@Pl-zeinNPs, it was found that when the zein-to-Sil ratio of 10:1 (w/w), Pl (0.5 mg/mL), the Sil@Pl-zeinNPs were uniformly distributed and showed smooth spherical shape with an average particle size of about 115 nm. In addition, Sil@Pl-zeinNPs exhibited high encapsulation efficiency (96.93%), remained stable under extreme environments such as strong acids, high temperatures and high salinity, and did not precipitate or aggregate after many days of storage, probably due to zein being encapsulated by pullulan (Pl) to enhance the stability of the drug delivery system. Finally, in vitro experiments have shown that Sil@Pl-zeinNPs could achieve sustained release of Sil while further enhancing antioxidant capacity. Overall, the present study provides a novel and effective delivery system for chemically unstable hydrophobic compounds such as Sil.