Design and synthesis of delivery system based on SBA-15 with magnetic particles formed in situ and thermo-sensitive PNIPA as controlled switch

A novel responsive carrier system based on ordered mesoporous silica SBA-15 was synthesized, with magnetic particles formed in situ and thermo-sensitive poly(N-isopropyl acrylamide) (PNIPA) polymerized inside the pores. It was interesting to find that the obtained system held a relatively large pore diameter (3.8 nm) and pore volume (0.47 cm(3) g(-1)), which would benefit for drug storage with relatively large molecules. The delivery system displayed a hysteresis loop with a saturation magnetization (M-s) of 0.40 emu/g, which revealed the magnetic property of the prepared system. In vitro test of ibuprofen (IBU) loading and release exhibited a pronounced transition at around 17 degrees C, indicating a typical thermo-sensitive release property for this delivery system. (c) 2007 Elsevier Inc. All rights reserved.