The Preparetion Of Nano-Magnetic Hollow Silica Microspheres And Their Application In Drug Loading

Hollow microspheres with nano-structures had potential applications in the controlled and sustained release of drug and dye, protection of bio-active molecules, catalytic field, wastewater treatment, and so on. Many methods were used to synthesize the hollow spheres. Pickering emulsions template method was a feasible and simple way to synthesize hollow spheres, which didn’t need to remove the template by calcination or dissolution, or use lots of toxic surfactants. It provided a novel and simple method for designing and controllable preparing hollow spheres, in particular, the composite hollow spheres.In this paper, modified Fe3O4 nano-particles were used to stabilize Pickering emulsions. Magnetic Hollow Silica Microspheres (MHSM) were prepared using poly-methyltriethoxysilane (PMTES) as silica source by Pickering emulsions template method. The particle size of MHSM was about 2μm, with a wall thickness of about 120nm. Hollow spheres had a smooth surface and a good mechanical strength. The effects on the hollow spheres with different experimental conditions were also investigated.In-situ drug-loaded Magnetic Hollow Silica Microspheres(IMHSM) and Breech-loading Magnetic Hollow Silica Microspheres(BMHSM) were also prepared by Pickering emulsions template method. TEM, XRD and IR were used to characterize the composition and structure of IMHSM and BMHSM. The particle size of IMHSM was about 2μm, with a smooth surface and a wall thickness of about 240nm; the particle size of BMHSM was about 1μm, with a rough surface and a wall thickness of about 75nm. Ibuprofen was added in the process of in-situ preparation, which maybe had an effect on the formation of the drug-loaded hollow spheres. The wall thickness of hollow spheres had increased, the same as its mechanical strength. And we also evaluated the release properties of DMHSM. The hollow spheres of the in-situ preparation could release the drug fast in first lOmin, and it tended to be stable at later stage, the release amount could be up to 80%; The hollow spheres were synthesized by the breech-loading preparation, the release rate was mitigation and the release amount could be up to 90%. Comparing with the two drug-loaded methods, the in-situ preparation had one-step shape, simple operation. Its hollow spheres had good morphology and mechanical strength.