Release of flurbiprofen using of SBA-15 mesoporous silica: Influence of silica sources and functionalization

In the present study, SBA-15 silica materials synthesized from different silica sources (S15(T) and S15(S)) and functionalized by post-grafting method with trimethylmethoxysilane (F-S15(T) and F-S15(S)) were compared as drug carriers for flurbiprofen (FBP). The physical state of the drug in the samples was characterized by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD). The results showed that the FBP molecules were not arranged in a crystalline form after incorporation of FBP into the pores of the SBA-15 samples. Surface functionalization resulted in decreased surface area, pore size, and pore volume of S15(T) and S15(S), which decreased the drug-loading capacity from 27.09% to 13.59% and from 16.96% to 9.19%, respectively. The in vitro drug release testing demonstrated that functionalized SBA-15 samples showed slower release rates compared to the non-functionalized samples. The results indicate that F-S15(T) (which had the smallest pore size) showed controlled drug release profiles without burst-release while the other silica samples showed faster release profiles than F-S15(T), indicating that pore size and hydrophobicity influenced the rate of the drug release process. The drug release mechanism of all the samples was found to be Fickian diffusion. (C) 2016 Elsevier B.V. All rights reserved.