Magnetic Mesoporous Silica Spheres for Drug Targeting and Controlled Release

Magnetically functionalized mesoporous silica spheres with different size (average diameter, A.D.) from 150 nm to 2 μm and pore size distribution were synthesized by generating magnetic Fe x O y nanoparticles onto the mesoporous silica hosts using the sol−gel method. The X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), N 2 adsorption/desorption results show that these composites conserved regular sphere morphology and ordered mesoporous structure after the formation of Fe x O y nanoparticles. XRD and X-ray photoelectron spectroscopy (XPS) analysis confirmed that the Fe x O y generated in these mesoporous silica hosts is mainly composed of γ-Fe 2 O 3 . Magnetic measurements reveal that these composites with different γ-Fe 2 O 3 loading amounts possess super-paramagnetic properties at 300 K, and the saturation magnetization increases with increasing Fe ratio loaded. The ibuprofen-containing spheres were then coated with biodegradable poly(DL-lactide-co-glycolide) (PLGA) by the S/O/W single-emulsion method. The PLGA hybrid magnetic spheres realize a reduced initial burst with a sustained release stage lasting for 20 days. These composites with or without the PLGA can be used as potential vectors for drug targeting and controlled-release systems.