Time filter

Source Type

Gonzalez Hurtado M.,Engineering and Chemical Research Center | Gonzalez Hurtado M.,University of Habana | PimentaCheble Caplan S.,Federal University of Rio de Janeiro | Guenther Soares B.,Federal University of Rio de Janeiro | And 4 more authors.
Journal of Materials and Environmental Science | Year: 2015

Threehydroxylatedtitanium matrixloadedwith ibuprofen (TiO2OH-IBU) were obtained by the sol-gel method using different molar ratio of alkoxide / water. These nanostructured materials (NM) were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning microscopy (SEM), Thermogravimetric analysis (TGA) and N2 adsorption isotherm. As water/alkoxide ratio increases, the specific surface areas for the composites (TiO2OH-IBU) and also for references (TiO2OH-Ref),(without ibuprofen) decreased, being more pronounced in the latter case. By contrast, the average pore diameter increases following the same trend being more remarkable for references. Finally, the analysis showed mesopores and micropores. FTIR indicates the presence of hydroxyls and also water physically adsorbed, but hydroxyls free were not observed. Also, higher water/alkoxide ratios enable the production of materials with negligible non-hydrolyzed alkoxide as TGA and FTIR results indicate. It was observed that ibuprofen incorporated to the composites corresponds to 7%w. by TGA. Analysis of X-ray diffraction showed that for reference (TiO2OH-Ref) withamolarratioalkoxide/water (1:24) the presence of anatase phase even at room temperature and that ibuprofen prevents crystallinity.Therelease of the drug for these systems was analyzed in vitro, showing typical controlled release profiles for all materials studied.This behavior could be evaluated for its use in implants near the affected area or in topical forms.

Gonzalez M.,Engineering and Chemical Research Center | Gonzalez M.,University of Habana | Soares B.G.,Federal University of Rio de Janeiro | Magioli M.,Federal University of Rio de Janeiro | And 2 more authors.
Journal of Sol-Gel Science and Technology | Year: 2012

The present work describes for the first time a new, simple and environmentally friend procedure for preparing polyaniline/silica hybrid materials by combining the sol-gel method and in situ polymerization of aniline. The hybrid materials were characterized by X-ray diffraction, scanning electron micrography, Fourier transform infrared spectroscopy, 29Si CPMAS solid state nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The hybrids displayed lower electrical conductivity, but higher crystallinity degree than pure PAni. Also electromagnetic interference shielding effectiveness (EMI SE) in the frequency range from 8 to 12 GHz of the hybrid materials containing up to 55 %of silica was similar to that found for pure polyaniline but with higher absorbed power, mainly in lower frequency range. This work demonstrates for the first time that it is possible to obtain PAni/silica-based EMI shielding hybrid materials with similar efficiency as pure polyaniline but with higher thermal stability. © Springer Science+Business Media, LLC 2012.

Fernandez Ledesma E.,Engineering and Chemical Research Center | Rodriguez Acosta C.,Engineering and Chemical Research Center | Liva Garrido M.,University of Habana | Diaz Polanco I.,Center for Research and Drug Development | Cazanave Guarnaluce D.,Center for Research and Drug Development
Journal of Materials and Environmental Science | Year: 2015

The pharmaceutical industry employs Aerosil 200V as an excipient in various formulations in a range of concentrations from 0.5 to 20%. The objective of the present work is to evaluate the behavior of silicon dioxide obtained from rice husk as a substitute for Aerosil 200V in the formulation of Valsartan 160 mg tablets. This new material was characterized and recognized its physical, mechanical and technological properties. Three pilot batches of tablets were manufactured and evaluated employing the rice husk ash and Aerosil 200V. Stability studies were done during six months including moisture influence during storage period. The rice husk ash meets established quality specifications in the pharmacopoeia USP and BP to colloidal silicon dioxide. At zero and six months the analyzed parameters were within the ranges established in the manufactured tablets with the two materials. It is possible to use silicon dioxide obtained from rice husk as an excipient in the Valsartan 160 mg tablets formulation as a substitute for Aerosil 200V and so decreasing agro-industrial waste.

Ledesma E.F.,Engineering and Chemical Research Center | Acosta C.R.,Engineering and Chemical Research Center | Garrido M.L.,University of Habana | Gonzalez M.C.,Engineering and Chemical Research Center | And 6 more authors.
Journal of Materials and Environmental Science | Year: 2012

In this work we provide the technological parameters for obtaining silicon dioxide from rice husk for its possible use at the pharmaceutical industry. We also show the results obtained in the chemical and physical analysis. The Cuban rice variety (M-10) was characterised and the results were compared with similar data from the literature. Preliminary tests conducted to 23 full factorial design, taking as dependents variables the loss percentage, the silicon dioxide percentage and the sample coloration. The independents variables were the concentration of hydrochloric acid, the temperature and the calcination time. Optimal conditions included washing of the rice husk with hydrochloric acid 1M and calcination at 700 °C during 1 hour. The results derived from the chemical and physical characterisation were within the established range. This work allows the use of an industrial residue, reducing the environmental pollution caused by the accumulation of solid waste.

Gonzalez M.,Engineering and Chemical Research Center | Gonzalez M.,University of Habana | Rieumont J.,University of Habana | Figueras F.,CNRS Research on Catalysis and Environment in Lyon | Quintana P.,CINVESTAV
Journal of Materials Research | Year: 2011

Titanium oxide matrix was prepared by sol-gel adding fluoxetine [Prozac (C17H18NF3O)] during the reaction of gelation. This nanostructured material was studied by Fourier transform infrared (FTIR) spectroscopy, N2 adsorption, and x-ray diffraction to detect the interaction between the drug and the matrix. The complex nature of FTIR signals for the matrix and the drug did not allow observation of the interactions; however, using the density functional theory formalism, two stable complexes are suggested to be formed on the drug matrix system. Both complexes are formed through H bond interactions involving the amine group in fluoxetine and the hydroxylated sites in titanium xerogel. They were found to be energetically stable and independent of the titanium model core cluster used in the calculations. © Copyright Materials Research Society 2011.

Loading Engineering and Chemical Research Center collaborators
Loading Engineering and Chemical Research Center collaborators