Inclusion of poorly soluble drugs in highly ordered mesoporous silica nanoparticles

Silica nanoparticles (MSNs) with a highly ordered mesoporous structures (103A) with cubic Im3 m have been synthesized using triblock copolymers with high poly(alkylene oxide) (EO) segments in acid media. The produced nanoparticles displayed large specific surface area (approximately 765 cm(2)/g) with an average particles size of 120 nm. The loading efficiency was assessed by incorporating three major antiepileptic active substances via passive loading and it was found to varying from 17 to 25%. The state of the adsorbed active agents was further analyzed using differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD). Dissolution studies revealed rapid release profiles within the first 3 h. The viability of 3T3 endothelial cells was not affected in the presence of MSNs indicating negligible cytotoxicity. 2009 Elsevier B.V. All rights reserved.

Characterization of carbonated tricalcium silicate and its sorption capacity for heavy metals: A micron-scale composite adsorbent of active silicate gel and calcite

Adsorption-based processes are widely used in the treatment of dilute metal-bearing wastewaters. The development of versatile, low-cost adsorbents is the subject of continuing interest. This paper examines the preparation, characterization and performance of a micro-scale composite adsorbent composed of silica gel (15.9 w/w%), calcium silicate hydrate gel (8.2 w/w%) and calcite (75.9 w/w%), produced by the accelerated carbonation of tricalcium silicate (C(3)S, Ca(3)SiO(5)). The Ca/Si ratio of calcium silicate hydrate gel (C-S-H) was determined at 0.12 (DTA/TG), 0.17 ((29)Si solid-state MAS/NMR) and 0.18 (SEM/EDS). The metals-retention capacity for selected Cu(II), Pb(II), Zn(II) and Cr(III) was determined by batch and column sorption experiments utilizing nitrate solutions. The effects of metal ion concentration, pH and contact time on binding ability was investigated by kinetic and equilibrium adsorption isotherm studies. The adsorption capacity for Pb(II), Cr(III), Zn(II) and Cu(II) was found to be 94.4 mg/g, 83.0 mg/g, 52.1 mg/g and 31.4 mg/g, respectively. It is concluded that the composite adsorbent has considerable potential for the treatment of industrial wastewater containing heavy metals.