Loading and release of Ibuprofen (IBU) in a novel network hollow magnetic mesoporous SiO2/Fe3O4 microspheres (HMMSs)

Abstract

The hollow magnetic mesoporous SiO2/Fe3O4 microspheres with different pore sizes were prepared by adjusting the addition of swelling agent (1, 3, 5-trimethylbenzene). The hollow magnetic mesoporous SiO2/Fe3O4 microspheres were modificated with different degree of aminopropyl groups via co-condensation method. The specific surface area, pore size, pore volume and ibuprofen loading of obtained composite microspheres were investigated in detail. The results showed that ibuprofen loading was increased with the mesoporous size increasing, and addition of swelling agent can improve the mesoporous size. When the pore size was up to 3.79 nm, ibuprofen reached the highest loading amount (816 mg/g). After modification of the aminopropyl group, which was located in the mesoporous channel, the ibuprofen loading was slightly reduced but the release rate of IBU was significantly decreased. Optimal release properties were achieved when the modification amount of the aminopropyl group was 10%, the ibuprofen continued to be released even after 32 h and the total release quantity is 70%, while the IBU release amount was 93% in the non-functionalized composite microspheres in 12 h. Meanwhile, the Korsmeyer–Peppas equation Q = kt n was employed to analyze the drug release profile. The hollow magnetic mesoporous SiO2/Fe3O4 microspheres had a high magnetization saturation value of 39.4 emu/g, which demonstrated a good responsivity to magnetic fields.