Obtenção de pseudoboemita a partir de NaOH e AlCl3.6H2O para liberação controlada de fármacos

• Autor(a) principal: Nascimento, Alber Luiz do
• Data de Publicação: 2016
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações do Mackenzie
• Texto Completo: http://dspace.mackenzie.br/handle/10899/24226
• topic: pseudoboemita; liberação controlada de fármacos; aciclovir; nanomateriais inorgânico não metálicos; processo sol-gel; CNPQ::ENGENHARIAS::ENGENHARIA DE MATERIAIS E METALURGICA

Sol-gel-obtained pseudoboehmite, an aluminium monohydroxide, is a poorly crystalized, non-metallic, synthetic, inorganic nanomaterial with both high purity level and specific area (SA). Studies are currently beeing carried in order to use it in the controlled liberation of drugs. Drugs of controlled delivery aim at releasing therapeutic dosages of a drug to a certain area of the body, keeping the desired concentration, release speed and adequate retention time as well as maintaining optimal blood levels, thus avoiding, on plasmatic levels, the problem of toxic doses. The present work seeks to obtain Pseudoboehmite of high purity and specific area, key characteristics for its use as support to controlled release of Acyclovir. To this purpose, it is essential to control all variables of the process so that the resulting product displays characteristics such as high performance, process reproducibility, continued stability and consistent physical-chemical properties. The variables to be controlled during synthesis are: raw materials, precipitation technique, reagent content in the reaction radium, precipitation temperature, agitation of the reacting medium, aging condition and specially pH control. Pseudoboehmite nanoparticles were obtained through sol-gel process using aluminum chloride hexahydrate in sodium chloride solution as a precursor and sodium hydroxide. The synthesized samples were characterized by X-Ray Diffraction, Scanning Electron Microscopy, Thermogravimetric Analysis, Differential Thermal Analysis and Adsorption Isotherms, observing the variations in the resulting phases and their relations with the variations of the molar concentrations. The Acyclovir adsorption with the synthesized pseudoboehmite was tested in solutions simulating its dissolution in the gastric juice in HCl 0,1 mol/L (pH 1-2) solution and plasma absortion in the simulation of the intestinal system (H2O and pH 6,5-7,5) and characterized by High Performance Liquid Chromatography. Results show that samples synthesized from 0,5M OH- had characteristic peaks in the X-Ray diagram of the pseudoboehmite structure (boehmite), while samples synthesized with smaller molar concentration (0,4M OH-) had peaks characteristic of the bayerite and boehmite structures. Synthesized samples of 0,5 M de OH- concentrations had specific area greater than 139m2/g on average. We noticed that the sample aging reduces mass loss in 36% on average, as seen in the Thermogravimetry (TG), in the samples and that it is also responsible for 46% increase, on average, of the pseudoboehmite sample in the crystaline phase. The adsorption isotherms show that the non-aged samples had a specific area 106 m2/g bigger than that of non-aged samples. The effects of these results can be seen in the answers regarding the pseudoboehmite study as excipients in the controlled release of Acyclovir, which kept its chemical stability without degrading the pseudoboehmite or drug, rendering the solubilization of the drug.