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 (S15T and S15S) and functionalized by post-grafting method with trimethylmethoxysilane (F-S15T and F-S15S) 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 S15T and S15S, 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-S15T (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-S15T, 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.