Pore ordering and surface properties of FDU-12 and SBA-15 mesoporous materials and their relation to drug loading and release in aqueous environments

The adsorption and release of drug molecules from silica-based cubic cage-like FDU-12 and hexagonal planar SBA-15 materials cubic have been tested as a function of the surface properties and chemical structure. The surface of mesopores has been alternatively functionalized using 3-mercaptopropyl trimethoxysilane (MPTS) and N-(2-aminoethyl)-aminopropyl dimethoxymethylsilane (APMS), which induce negative and positive surface charges respectively on the silica surface. For testing adsorption and release capacities, both antibiotic cefuroxime and vancomycin molecules are considered. The drug molecules reach the inner part of mesopores, as can be confirmed after XPS depth profiling analysis, pointing to a homogeneous loading. The 3D cubic structure and large size of spherical mesopores of FDU-12 materials enhance the antibiotic load per unit surface area and show a more sustained drug release under similar conditions than SBA-15.