Fabrication and sustained release properties of porous hollow silica nanoparticles

MCM-41-type mesoporous silica nanospheres (MSN) have been prepared using n-cetyltrimethylammonium bromide (CTAB) as a soft template. The pseudo-moire' rotational pattern inside the MSN results in many interior defects. Hollow mesoporous silica (HMS) spheres were synthesized by solvent extraction of the template from MSN. The morphology and structure of MSN and HMS were studied by TEM, XRD and nitrogen sorption techniques. A model drug, bromocresol green dye, was packed inside different regions of HMS through impregnation at different pressures and temperatures, and the drug release performance of the resulting materials was compared. The results showed that vacuum evaporation of solvents may enhance the controlled release properties.