Influence of functionalization type on controlled release of emodin from mesoporous silica

Abstract

Emodin drug was introduced into the porous mesochannels of (γ-chloropropyl)triethoxysilicane (CPTES) and (3-aminopropyl)triethoxysilane (APTES) functionalized SBA-15 via a hydrothermal process. The pure, functionalized and drug loaded mesoporous materials were characterized by small angle X-ray powder diffraction, field scanning electron microscopy, high resolution transmission electron microscopy, nitrogen adsorption–desorption, Fourier transformed infrared spectra, and UV–visible spectrophotometry. The functionalization of mesoporous silica reduced the degree of crystallinity of the resulting material. High resolution transmission electron microscope images of the functionalized materials demonstrated the reservation of the hexagonal mesoporous structure of SBA-15. Pure, CPTES and APTES-functionalized mesoporous silica were employed as base materials for the controlled release of emodin drug. Drug loading results revealed that the loading capabilities largely depend on the specific surface area, and pore volume and pore diameter of the carrier matrix. Emodin drug release profiles were studied in phosphate buffered saline with pH 7.4, and outcomes specified that the drug release rate could be controlled by the surface CPTES and APTES-functionalized carrier matrices. Emodin loaded functionalized materials presented a lower release rate compared to that of the pure SBA-15. Emodin loaded APTES-functionalized SBA-15 presented the lowest release amount of 74.5 % even up to 60 h. These results propose that the functionalized mesoporous silica is a favorable drug carrier for accomplishing prolonged release time.