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.