This paper deals with the development of a kind of water-in-oil-in-water (w/o/w)
multiple-emulsification method to fabricate the SF drug-loading microspheres. The silk fibroin (SF)
microspheres were prepared by using 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 average
size of microspheres varied from 6.53 μm to 68.60 μm. The structure of SF drug-loading microspheres
had an obviously change compared with pure SF; and the change is the appearance of silk I and silk
II structures; and its molecular conformation was β-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 ‹ acetone ‹ ethanol. Drug
release of SF drug-loading microspheres: there was a slow release effect when the concentration of SF
was 3% or 6%. Moreover, in the experimental condition, there was an obvious burst release of the drug
when the SF concentration was 9 % or 12 % or when the treated solvent was ethanol.
