Poly (vinyl alcohol)/SiO_2 composite microsphere based on Pickering emulsion and its application in controlled drug release

摘要

In this paper, with W/O Pickering emulsion stabilized by'modified SiO_2 nanoparticles as template, PVA/SiO_2 composite-microspheres with PVA hydrogel cores and shells of SiO_2 nanoparticles are successfully fabricated through freezing/thawing method. The final structure and constituents of the products are investigated through SEM, FTIR, and TGA. The PVA/SiO_2 composite microspheres obtained are applied as a drug carrier to study their controlled release behaviors and methylene blue is used as a model drug. The effect of PVA concentration, SiO_2 nanoparticle concentration, and freezing/thawing cycles on the morphology of products and release behaviors is studied. All release curves are, respectively, fitted by Monoexponential equation, Higuchi equation, Weibull equation, and Hixson-Crowell equation. Weibull equation is found to give the best fitto the release process. The fitted results prove that the drug release from the PVA/SiO_2 composite microspheres follows Fick diffusion.