Preparation of novel hollow mesoporous silica spheres and their sustained-release property

Novel hollow mesoporous silica spheres (HMSs) with uniform size and morphology have been successfully synthesized in a facile route using poly(vinylpyrrolidone) (PVP) and cetyltrimethylammonium bromide (CTAB) as co-templates at room temperature. XRD, N₂ adsorption-desorption analysis, FE-SEM, and TEM are used for the characterization of the structure. The hexagonally ordered pore channels are formed on the shell. Ibuprofen (IBU) as a model drug is used to examine the storage capacity and the release behaviour of drug molecules. The storage capacity of hollow mesoporous silica spheres can reach 1133 ± 52.4 mg g^-1 for ibuprofen, which is three times higher than that of conventional mesoporous materials previously reported (337 mg g^-1), and the storage capacity is adjustable in a wide range. Furthermore, this system also shows a sustained-release behaviour. The release rates from the IBU-HMSs system (IBU stored in HMSs) increase with the decrease of pH values and the release process follows a Fick's law.