Silk fibroin (SF) microspheres were prepared by water-in oil-in-water double-emulsification with SF as vehicle and dexamethasone sodium phosphate (DSP) as
drug model. The surface morphology was observed by SEM, the particle diameter and its
distribution were observed with Laser particle sizer. The structure was studied by X-ray
diffraction and Fourier transform infrared. The properties of drug release were assessed in
vitro. The results showed the drug-loading microspheres average size varied from 6.53 mu m to
68.60 mu m. The structure of SF drug-loading microspheres had an obviously change compared with
pure SF, and appeared silk I and silk 11 structures, and its molecular conformation was P-sheet.
The average drug-loading varied from 5.32 % to 9.01 %, and the average loading varied from 56.43%
to 99.07%. The drug-loading and loading efficiency increased with the increase of SF
concentration. The drug-loading and loading efficiency differed when the treated organic solvent
differed, their order is: isopropanol
microspheres: there was a slow release effect when the concentration of SF varied from 3% to 6%.
In the experimental condition, there is an obvious burstrelease of the drug when the SF
concentration is 9% and 12% or when the treated solvent is ethanol.