APTES-functionalized mesoporous silica as a vehicle for antipyrine – adsorption and release studies

Abstract

In this study the mesoporous silicas SBA-15 and SBA-16 were functionalized with 3-aminopropyltriethoxysilane (APTES). The materials obtained were characterized by infrared spectroscopy, X-ray diffraction, low-temperature nitrogen sorption, laser diffraction, elemental analysis, zeta potential measurements, scanning and transmission electron microscopy. The introduction of amine groups changes the textural parameters of mesoporous materials. Antipyrine was selected as a model drug to be loaded on the modified mesoporous silica and released in the medium of the simulated gastric fluid and phosphate buffer with a pH of 7.2. The antipyrine adsorption process was more effective onto the pure silica than onto amino-functionalized samples. Furthermore, it was proved that SBA-16 with cubic structure was a better drug vehicle than SBA-15 with hexagonal structure. The release behaviour of antipyrine was highly dependent on the surface properties of mesoporous materials. The presence of amine groups on the surface of silica was found to increase the amount and rate of antipyrine release regardless of the pH conditions.