Aos meus pais, Antonio e Cristina. AGRADECIMENTOS Ao meu orientador, Professor Dr. Francisco Rolando Valenzuela Diaz, pelo apoio e liberdade concedidos na execução deste trabalho. Agradeço-o pela confiança em minha capacidade e por ter me acolhido para conversarmos sobre ideias de pesquisa para o mestrado quando eu ainda estava no final da graduação. Agradeço-o, sobretudo, por ser um orientador calmo e paciente, sempre respeitando minhas dúvidas e meu ritmo de trabalho. Ao Professor Dr. Roberto de Freitas Neves, pela amizade e contribuições valiosíssimas para o desenvolvimento desta dissertação. Posso dizer, sem nenhum exagero, que ele foi um dos maiores responsáveis por eu ter conseguido terminar meu mestrado! Seu jeito bem-humorado e otimista foi fundamental para levantar o meu ânimo e o das minhas colegas. As conversas que tivemos sobre assuntos não acadêmicos ou pesquisa, ora sobre meu mestrado, ora sobre seu projeto de pós-doutorado, tornaram minha experiência no laboratório mais descontraída. Ao Professor Dr. Antônio Hortêncio Munhoz Júnior, pelas valiosas contribuições e sugestões para este trabalho, especialmente na ocasião do meu exame de qualificação. Às minhas colegas de grupo de pesquisa, Thamyres, Margarita, Jéssica e Bianca, pela amizade e convívio no laboratório. Agradeço à Margarita especialmente por ter realizado meus ensaios de difração de raios X. Agradeço muito à Bianca por ter lido o texto do meu exame de qualificação minuciosamente, fazendo comentários e sugerindo alterações. À Professora Dra. Maria das Graças da Silva Valenzuela pela gentileza de ter realizado meus ensaios de espectroscopia de infravermelho. Ao Dr. Flavio Machado de Souza Carvalho, do Instituto de Geociências da USP, por ter compartilhado comigo um pouco do seu conhecimento sobre difração de raios X e método de Rietveld. À Suellen Alves, por ter me ajudado, sempre solicitamente, a esclarecer minhas dúvidas sobre os trâmites burocráticos da pós-graduação.
Recently, the incidence of American Cutaneous Leishmaniasis (ACL) has been grown in Latin America, especially in Brazil, where from 1980 to 2005, 605,062 cases were recorded. The drug glucantime®, whose active principle is the meglumine antimoniate (or meglumine antimonate) is used in the treatment of leishmaniasis. Its toxicity is due mainly to the presence of antimony in its structure. Therefore, it is crucial to determine the safe dose levels of this drug in the treatment. Drug delivery systems have been currently the focus of many studies due to its effectiveness in treating diseases proved to be superior compared to conventional methods. Drug delivery systems can avoid overdosing by decreasing the amount of drug intake, which results in a better therapeutic effect in addition to reducing the risks of plasma concentration reaching toxic levels. Synthetic nanomaterials have been receiving great attention due to their potential applications in pharmaceutical technology as well as the possibility of controlling their particle size and composition, which allows a better performance in drug release. Pseudoboehmite is a synthetic aluminum compound precursor of alumina [1] and a polymorph of boehmite, with active groups in its structure [2], making it an excellent adsorbent material. In this work, pseudoboehmite was prepared by using the sol-gel process for being used as an excipient. The incorporation of pseudoboehmite in glucantime® was performed in the processing of tablets. Both pseudoboehmite and the tablets were characterized via X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TG), and scanning electron microscopy (SEM) using secondary electron detector and EDS detector. The release profile was obtained by UV/Vis spectroscopy for in vitro simulation. No reaction between the drug and the excipient was observed.
Kaolin is a cheap and abundant source of silica and alumina, which may be used as precursors for the production of zeolites, molecular sieves with pores in the nanometer scale. Brazil, one the largest producers of kaolin, generates tons of kaolin waste in the paper coating process. That waste may be used to synthesize zeolite A and hydroxysodalite, greater added value materials with a wide range of applications. In this work, Zeolite A and hydroxysodalite were synthesized from kaolin waste of processing industries for paper coating. Kaolin was calcined to dehydroxylate kaolinite and obtain metakaolin, an amorphous material with Si/Al ratio equal to 1, being suitable for production of zeolite A and hydroxysodalite. Zeolites were synthesized under static hydrothermal conditions by reacting metakaolin with NaOH solutions of different concentrations. The zeolitic products were characterized by means of X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The results showed that the higher the NaOH concentration in the reaction medium, the higher the proportion of hydroxysodalite in the zeolitic samples.
The aim of this work was to synthesize eight samples of pseudoboehmite obtained by the sol-gel process under different conditions in a two level factorial experimental design consisting of three variables. It was observed how the properties of pseudoboehmites (crystallinity and morphology) were affected by the three analyzed variables, namely: aging temperature, aging time and addition of polyvinyl alcohol. The samples were characterized by x-ray diffraction, scanning electron microscopy with secondary electrons detector, differential thermal analysis, and thermogravimetric analysis. After being characterized, the pseudoboehmite powders were calcined in an electric furnace at 500°C. After calcination, the resultant powders were analyzed via x-ray diffraction. One of the most important results achieved in this work was the successful synthesis of gamma-alumina from pseudoboehmite, as well as high crystallinity in the pseudoboehmite samples aged at high temperatures.
Different samples of pseudoboehmite (PB) were synthesized through the sol-gel process, using aluminum nitrate as precursor. The influence of variables on the synthesis and calcinations of the PB on the specific area of the obtained gamma-Alumina were studied. The variables were the ageing temperature (25 and 130o C), addition or not of polyvinyl alcohol to the precursor solution and the ageing time of the PB. The pH adjustment of the precursor solution was made by using ammonium carbonate. The products, which were obtained on different conditions, were then characterized by x-ray diffraction, specific area measurements through the BET process, and by thermal analysis (DTA and TG). After characterization, the synthesis products were calcined at 500°C; during this process the gamma-Alumina transformation was observed. The calcination products were characterized by the same methods (x-ray diffraction, BET, DTA and TG) and the desorption-absorption curves were obtained as well, in order to measure the pore volume of the samples. Finally, the results were analyzed through an experimental factorial planning, which showed that high specific surface area gamma-Al2O3 (around 330m²/g) can be obtained through this process.
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