Carboxylic modified spherical mesoporous silicas as drug delivery carriers

The present study deals with the development and functionalization of mesoporous silica nanoparticles as drug delivery platforms. Spherical MCM-41 and SBA-15 silicas with different pore sizes (2.7 nm and 5.5 nm, respectively) were post-synthesis modified applying a new, two step process. The initial step was the modification with 3-amino-propyltriethoxysilane, and the next was the reaction with succinic anhydride in toluene in order to obtain carboxylic modified mesoporous carriers. The carboxylic-functionalized mesoporous materials were characterized by XRD, nitrogen physisorption, TEM, ATR FT-IR spectroscopy. The successful carboxylic functionalization was proved by the changes of the zeta potential of the mesoporous materials before and after modification. The parent and the carboxylic-modified MCM-41 and SBA-15 materials showed high adsorption capacity (approximately 50 wt.%, except for non-functionalized MCM-41) for sulfadiazine that possesses amino functional groups. Mesoporous structure peculiarities lead to different adsorption capacities on the carriers. In vitro release studies showed slower release rate of sulfadiazine from carboxylic modified MCM-41 and SBA-15 mesoporous particles compared to the non modified ones. Both non loaded and drug-loaded silica materials demonstrated no cytotoxicity on Caco-2 cell line. The functionalized mesoporous systems are appropriate drug delivery platforms due to their biocompatibility and the possibility to modify drug release. (c) 2012 Elsevier B.V. All rights reserved.