Mesoporous silica materials functionalized with folic acid: preparation, characterization and release profile study with methotrexate

Ordered mesoporous silica materials exhibit potential features to be used as controlled drug delivery systems, including biocompatibility, textural and structural properties. In this paper, ordered mesoporous materials SBA-15, SBA-16 and MCM-41, which present different morphologies, pore sizes and array of mesopores (2D hexagonal, 3D cubic and 2D hexagonal, respectively), were synthesized, functionalized with folic acid by post-synthesis grafting and loaded with the anticancer agent methotrexate. The drug loading and its release kinetics profile were compared between all materials. The mesoporous silicas were characterized through thermogravimetric analysis, CHN elemental analysis, Fourier transform infrared spectroscopy, small-angle X-ray scattering, N-2 adsorption, zeta potential, scanning electron microscopy and transmission electron microscopy in order to evaluate their physical-chemical properties. The interactions between methotrexate and the materials' surface were systematically evaluated using X-ray photoelectron spectroscopy. The results showed the drug release kinetic might be controlled by the synthesis procedure and the degree of surface functionalization of the mesoporous silica.