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Mesoporous silica type SBA-15 has high specific surface area, well ordered pores and renders larges volumes, reasons for its potential use in controlled drug delivery system; in addition its non toxic nature and good biocompatibility. The aim of this work is to determine the feasibility of loading collagen-polyvinylpyrrolidone (collagen-PVP) molecules into Biocompatible Nanostructured Ordered Mesoporous Silica (BINOM-Silica). Collagen-PVP has several medical uses, such as fibrolytic activity and tissue regeneration. Therefore, this BINOM-Silica/collagen- PVP material could be used as drug delivery system for hypertrophic scarring. Different BINOMSilica materials were prepared using a triblock copolymer in an acid medium and stabilized at 557°C and later, collagen-PVP was loaded into the material. The small angle powder X-ray diffraction patterns of BINOM-Silica materials, in some cases, indicate the existence of a high degree of hexagonal mesoscopic organization. The nitrogen sorption isotherms are type IV typical of mesoporous materials with large surface area. In vitro release of collagen-PVP was carried out by mean of UV/VIS spectroscopy. The cumulative release profiles of Silica-collagen PVP in distilled water indicate a two step release, an initial fast release and a relatively slow subsequent release, indicating an appropriate delivery of collagen-PVP for therapeutic administration. BINOMSilica/ collagen-PVP intradermical administration stimulated inflammatory infiltrates only in an acute phase (day 3), demonstrating that silica materials and their combination with chemical and biological drugs could be safe for therapeutics. The absence of inflammatory infiltrates at day 7 suggested an appropriate integration of BINOM-Silica/collagen-PVP into the tissue. These results indicate that we obtained biocompatible nanostructured ordered mesoporous silica materials useful for delivery systems.

In vivo suppression of glioblastoma multiforme (GBM) in Wistar rats using silica-shelled biocatalytic Pt(NH3)4Cl2 nanoparticles is reported. These nanoparticles were synthesized by a sol-gel technique and characterized by SEM and HRTEM imaging. We confirmed morphological uniformity (30 nm) and surface acidity of the nanoparticles, respectively, by TEM imaging and FTIR spectral analysis. Interestingly, treatment of Wistar rats intraperitoneally inoculated with C6 cells using the biocatalysts resulted in considerable tumor shrinkage. Efficiency of the biocatalyst to shrink a tumor is superior to that by the commercial cytotoxic agent cisplatin. The tumor suppression property of Pt(NH3)4Cl2 nanoparticles is attributed to catalytic damage of DNA in C6 cells.

In this paper is reported the “in vitro” release kinetic studies of antiepileptic drugs released from an inorganic, titanium oxide (TiO2) porous matrix. In order to determine the drug release mechanism, the experimental values were fitted to different mathematical models: zero-order, firs-order, Higuchi, Hixson-Crowel and Peppas. TiO2 was prepared by the sol-gel method adding valproic acid (VPA) or phenytoine (DHP) during the titanium n-butoxide hydrolysis step. The drug-TiO2 systems were observed by scanning electron microscopy. The “in vitro” release experiments were performed at laboratory scale following the United States Pharmacopeia (USP) standards. The obtained materials have a morphology of nanoparticle agglomerates. The particles have different sizes with some roughness and spherical shape. Peppas model suggests for both systems, that the release mechanism is controlled by two parallel processes. The first one is by diffusion of the drug through the matrix and the second is related to a gradient of constant diffusion by ingress of the solvent in the matrix.

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