Functionalized silica matrices for controlled delivery of cephalexin

The surface of SBA-15 ordered mesoporous silica was functionalized with sulphonic and amine functional groups to determine the effect of changes in surface acidity on cephalexin adsorption and subsequent release. Cephalexin (CPX), which belongs to the group of cephalosporins or beta-lactam antibiotics, was impregnated on functionalized SBA-15. The functionalized silica materials were characterized by SEM, TGA, FTIR and N(2) adsorption, and an in vitro drug delivery test was performed. SEM micrographs showed the packed cylinders correspond to SBA 15 materials. Likewise, N(2) adsorption-desorption isotherms demonstrated that the SBA-15 structure was obtained when IV-type isotherms were displayed. The inalterable stabilization of the drug was confirmed by FTIR spectroscopy. For all the samples studied, the delivery profiles exhibit two steps. A fast initial stage was obtained over the first 5 h, followed by a slower one. Regarding this second stage, the time needed to attain a plateau was undoubtedly altered by the surface functionalization.