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Abstract: Mesoporous silica spheres with controllable particle size were synthesized in mixed ethanol–water solvent. These materials possessed same pore size distribution and pore channel geometry. The amount of ibuprofen (IBU) adsorbed in mesoporous channels increased with the surface area of mesoporous silica spheres. Three kinds of release fluids, simulated intestinal fluid (SIF, pH=7.4), simulated body fluid (SBF, pH=7.4), and simulated gastric fluid (SGF, HCl aqueous solution, pH=1.2) were used to investigate drug release. The effects of particle size and dispersancy of mesoporous spheres on drug release rate were discussed in detail. It was found that larger or agglomerate mesoporous silica spheres could delay the drug release process, which could be attributed to pore-mouth amount and mesopore channel length of mesoporous spheres. Furthermore, to obtain a well controlled drug release system, hydrophobic trimethylsilyl (TMS) groups were functionalized on the surface of mesoporous silica spheres. The release of IBU from TMS-functionalized mesoporous spheres was obviously delayed with the increase of TMS content. [Copyright &y& Elsevier]

Abstract: Serial of trimethylsilyl-carboxyl bifunctionalized SBA-15 (TMS/COOH/SBA-15) have been studied as carriers for controlled release of drug famotidine (Famo). To load Famo with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized by one-pot synthesis under the assistance of KCl. The mesostructure of carboxyl functionalized SBA-15 (COOH/SBA-15) could still be kept even though the content of carboxyl groups was up to 57.2%. Increasing carboxyl content could effectively enhance the loading capacity of Famo. Compared with pure SBA-15, into which Famo could be hardly adsorbed, the largest drug loading capacity of COOH/SBA-15 could achieve 396.9mg/g. The release of Famo from mesoporous silica was studied in simulated intestine fluid (SIF, pH=7.4). For COOH/SBA-15, the release rate of Famo decreased with narrowing pore size. After grafting TMS groups on the surface of COOH/SBA-15 with hexamethyldisilazane, the release of Famo was greatly delayed with the increasing content of TMS groups. [Copyright &y& Elsevier]