Synthesis and characterization of mesoporous Fe/SiO2 for magnetic drug targeting

Mesoporous Fe/SiO2 was synthesized as a carrier for magnetic drug targeting by using the sol–gel route and a chemical reduction method. It was confirmed that metallic iron clusters were formed and retained in the channels of the mesoporous silica by XRD and N2 adsorption. The magnetic properties and stability of mesoporous Fe/SiO2 were characterized by vibrating sample magnetometry and XPS. The oxidation of metallic iron and subsequent reduction of magnetic properties were retarded by the mesoporous silica framework and the surface-formed non-magnetic iron oxide layer. The release of ibuprofen from the mesoporous Fe/SiO2 was described as a diffusion-controlled process (Higuchi relationship). It showed two-step release composed of an initial burst and a slow steady release for 700 hours. This was due to the physical and chemical entrapping of drug in the mesoporous Fe/SiO2 particles. The release rate could be also controlled by surface modification of drug-loaded mesoporous Fe/SiO2 with a biologically compatible polymer such as PCL.