The use of rayon in 1920s and 1930s garments confronts conservators with new challenges: definitive fibre identification involves more than basic microscopy and treatment can be difficult with little available research on early rayon and its conservation. Rayon is expected to degrade similarly to other cellulosic fibres; however, since it is a regenerated fibre, rayon is at risk of doing so at a faster rate. The purpose of this research was to develop and test a protocol for the identification of viscose and cuprammonium rayon and to determine whether early rayon dresses have condition issues at this time. Polarizing microscopy, hot-stage microscopy, acetone solubility and relative fibre refractive index were explored as fibre identification techniques, resulting in the development of a rayon identification scheme. 1920s and 1930s rayon dresses were surveyed for condition and it was determined that dresses in this sample have limited condition issues at this time.

Abstract This work investigates the kinetics of the emulsion polymerization of vinyl acetate. Several aspects of this system have been clarified, including the induced decomposition of persulfate, retardation by oxygen and entry by, and analysis of, the aqueous phase oligomeric radicals. It has been shown that the retardation period observed in the emulsion polymerization of VAc can be explained by the effect of traces of oxygen (< 10-6 M) on the entry efficiency of the initiator-derived aqueous-phase oligomeric radicals. Comparison of rates of polymerization in V and persulfate -initiated polymerizations together with electrospray mass spectrometry of aqueous phase oligomers, has shown that the mechanism for the induced decomposition of persulfate by vinyl acetate is chain transfer to initiator from aqueous-phase oligomeric radicals. A value has been determined for the rate coefficient for transfer to initiator, by fitting literature data to a model based on this mechanism. The reported independence of the rate of polymerization from the monomer concentration in the emulsion polymerization of vinyl acetate has been investigated. Possible explanations for this behaviour have been proposed and tested in this work, by measuring radical-loss rates directly with y-relaxation techniques. Although the Y relaxations were found to be affected by experimental artefacts, it has been demonstrated that rapid exit is not responsible for the high radical-loss rates in this system. The major artefact identified in the y relaxations was the significant effect of relatively small exotherms on relaxation behaviour, Methodologies were developed for correcting affected data and for avoiding exotherms under certain conditions. Arrhenius parameters were determined for the rate coefficient for chain transfer to monomer using the In^M method, which utilises the whole MWD. This section of the work is incomplete, for reasons detailed in chapter 5. However, as a preliminary indication it was found that the frequency factor was 106.38 M-1 s-1 and the activation energy was 38.8 kJ mol-1.

Thesis(M.P.H.M. (Primary Health Care Management))--Mahidol University, 2004.

Ethylene-vinyl acetate co-polymers are widely used as cold-flow improving additives in diesel fuels. Although their functionality is undisputed, the mechanisms of action at a molecular level are not fully understood. Theories that EVA acts as both a nucleating agent for small wax crystals and as a crystal growth inhibitor are generally acknowledged, however the understanding of the effect of structure on additive performance is limited. Studies have been carried out using molecular simulation techniques with the aims of improving the understanding of the interactions between EVA and diesel fuels, and assessing the potential of these methods for the analysis of different additive structures and fuel compositions. Firstly, the ability of Monte Carlo simulations to predict the chemical potentials of n-alkanes in organic solvents was studied. This information would be of use in determining the characteristics of different fuel compositions. It was found that the particle insertion method used becomes more efficient as the aspect ratio of the solvent increases relative to that of the solute. Despite the identification of expected linear trends in the chemical potential of n-alkanes, it was not possible to produce high quality quantitative data using this method. The effect of vinyl acetate spacing and solvent environment on the configuration of lone EVA molecules in the liquid phase was studied. Molecular dynamics showed that closely spaced vinyl acetate groups increase the tendency of the molecule to fold at that point, whilst molecules with 2 or 3 ethylene groups in between show resistance to folding. It was shown that n-hexane as a solvent produced more folded configurations than benzene and n-hexadecane respectively. Monte Carlo simulations were also performed but were largely unsuccessful. Finally, molecular dynamics simulations were performed to study the effect of different EVA structures on the spontaneous crystallisation of n-hexadecane, and the interaction of the EVA with the resulting structures at a molecular level. It was shown that different EVAs had varying effects on the crystallisation, with trends attributed to the spacing of the vinyl acetate groups and the length and position of extended aliphatic sections of the EVA molecules. One molecule, with evenly spaced side-groups and no extended aliphatic sections was shown to fully prevent the formation of any crystalline structure within the time of the simulation where all other EVA molecules allowed some degree of wax formation to occur.

Introduction: The human menstrual cycle is regulated by sex-steroid hormones, including oestrogen (E), progesterone (P4) and androgens which act by ligand binding to their cognate receptors. Perturbation of the complex series of events governing the menstrual cycle may lead to heavy menstrual bleeding (HMB). This is a common debilitating condition and often associated with uterine fibroids. There remains an unmet need for effective, long-term medical treatment so women avoid surgery and preserve their fertility. Selective progesterone receptor modulators (SPRMs, e.g. ulipristal acetate, UPA) are synthetic ligands that bind the progesterone receptor (PR). Many SPRMs have been developed but only mifepristone (for the management of unwanted pregnancy) and UPA are in current clinical use. UPA is licensed for the intermittent treatment of symptomatic fibroids. SPRMs have potential utility for treatment of HMB as administration rapidly induces amenorrhoea but the mechanisms by which this is achieved are unknown. SPRM administration results in unique endometrial morphological changes (progesterone receptor modulator-associated endometrial changes; PAEC). Despite endometrial unopposed estradiol exposure these morphological changes do not appear to be associated with malignancy or pre-malignancy risk. Indeed endometrial cell proliferation appears reduced despite relative progesterone-antagonism. Based upon findings with other SPRMs it was hypothesised that: (i) administration of UPA would have an endometrial specific effect upon the reproductive tract, with regard to alteration in morphology, localisation of sex steroid receptors (SSR) and cell proliferation.; (ii) administration of UPA would impact upon progesterone-regulated (Pregulated) genes in the endometrium. Methods: The data presented within this thesis are derived from biopsies obtained at hysterectomy from the endometrium, fallopian tubes and cervices of women with symptomatic fibroids administered UPA for 8-15 weeks. Samples were obtained for histological assessment, immunohistochemistry and RNA extraction for subsequent quantitative RT-qPCR of sex-steroid receptors (SSR) and proliferation markers. In addition key P-regulated genes within the endometrium were investigated by RT-qPCR and selected protein expression. To further interrogate the anti-proliferative effect, RNA was extracted from “paired” endometrial biopsies from the same woman in the proliferative phase of the menstrual cycle and following subsequent treatment with UPA for at least eight weeks and microarray gene analyses undertaken. Results: Morphological alteration of the endometrium with UPA administration was consistent with previously published data, but with a higher prevalence than previously described. There was a striking alteration in expression and localization of SSRs, particularly PR and androgen receptor (AR), and alteration of many P-regulated genes, consistent with UPA acting with low progesteroneagonism within the endometrium. There was no alteration of SSR expression within the cervix and proliferation was unchanged. Fallopian tube morphology and SSR expression was consistent with proliferative phase but cell proliferation was reduced following UPA administration, consistent with secretory phase levels. Microarray analyses identified multiple transcripts altered relative to proliferative phase, with GREM2 the most significantly down-regulated gene and MUC1 one of the most significantly upregulated genes. Consistent with low levels of mitotic figures and cell proliferation, the most down regulated KEGG pathway was the cell cycle. Multiple elements within this were subsequently validated (RT-qPCR) and included key regulators of all elements of the mitotic cell cycle, many of which were novel to those previously described following administration of another SPRM, mifepristone. In summary the novel data presented in this thesis considerably extend the data available to date concerning the actions of the SPRM, UPA, on the female reproductive tract, and increases knowledge regarding a compound with promising utility for the management of the debilitating complaint of HMB.

Four negative stains, hafnium chloride and europium, samarium and gadolinium nitrates, were tested in single particle electron microscopy as potential alternatives to uranyl acetate, which is recently being widely restricted for its toxicity. The new stains were applied to a structurally well-described plant photosystem I, visualized by a transmission electron microscope and classified in a single particle analysis. The quality of the stains was evaluated by the obtained resolution and ability to provide reliable structural information.

Orientador: Maria do Carmo Gonçalves / Tese (doutorado) - Universadade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-13T18:47:11Z (GMT). No. of bitstreams: 1 Romero_RafaelleBonzanini_D.pdf: 28876791 bytes, checksum: 2296e157df643bcd91224ad26360f6ce (MD5) Previous issue date: 2009 / Resumo: Nanocompósitos de biopolímeros com silicatos lamelares podem ser desenvolvidos para criar uma nova classe de materiais eco-friendly, podendo contribuir para aplicações inovadoras de polímeros. Esses materiais têm despertado grande interesse, devido principalmente à facilidade de obtenção, bem como às suas propriedades químicas, físicas e mecânicas. Neste trabalho foram preparados nanocompósitos de acetato de celulose pelos métodos de intercalação em solução e no estado fundido, onde os efeitos de diferentes solventes, de agentes modificadores da argila e de condições de processamento foram investigados nas suas propriedades estruturais, morfológicas, térmicas e mecânicas. No método de intercalação em solução, os resultados obtidos indicaram que a dispersão e delaminação da argila são alcançadas somente quando ocorreram interações favoráveis entre o solvente, a argila e o polímero. Neste caso, os nanocompósitos apresentaram melhores propriedades térmicas e dinâmico-mecânicas em relação ao acetato de celulose puro. No método de intercalação no estado fundido, os resultados obtidos evidenciaram a intercalação do acetato de celulose entre as lamelas da argila, promovida pela afinidade química favorável entre o polímero, o plastificante e a argila. Além disso, as estruturas intercaladas foram parcialmente delaminadas sob ação do cisalhamento imposto durante o processo de extrusão, resultando em nanocompósitos com partículas intercaladas e também esfoliadas. Devido a estas características, os nanocompósitos obtidos apresentaram propriedades mecânicas e de barreira superiores às apresentadas pelo acetato de celulose puro. Baseado nos dois métodos investigados neste trabalho, pode-se concluir que a escolha apropriada dos aditivos e das condições de preparação é extremamente importante para promover interações favoráveis entre as partículas de argila e o polímero, que por sua vez são necessárias para a desejada melhora nas propriedades finais desses materiais / Abstract: Nanocomposites of bio-based polymers with layered silicates can be used to create new eco-friendly materials, and can open ways towards the innovative applications of polymers. These materials are interesting, mainly due to their easy preparation, as well as their chemical, physical and mechanical properties. Cellulose acetate nanocomposites was prepared in this work by using solution and melt intercalation methods, where the effect of the different solvents, clay modified agents and processing conditions were investigated in terms of their structural, morphological, thermal and mechanical properties. The obtained results, in the solution intercalation method, showed that the dispersion and delamination of the clay were reached only when favorable interactions were promoted between the solvent, clay and polymer. In this case, the nanocomposites presented enhanced thermal and dynamic-mechanical properties in relation to the pure cellulose acetate. The results obtained in the melt intercalation method showed the intercalation of the cellulose acetate chains into the silicate platelets, which was promoted by the favorable chemical affinity between the polymer, plasticizer and clay. Apart from this, the intercalated structures were partially delaminated by the shearing imposed during the extrusion process, resulting in nanocomposites formed by intercalated as well as exfoliated clay particles. Due to these characteristics, the nanocomposites presented enhanced mechanical and barrier properties compared to pure cellulose acetate. Based on the two methods investigated in this work, it can be concluded that the appropriate choice of additives and preparation conditions of preparation is extremely important to promote favorable interactions between the clay particles and the polymer, that in turn are necessary for the desired enhancement in the final properties for these materials / Doutorado / Físico-Química / Doutor em Ciencias Quimicas

Orientador: Adriana Vitorino Rossi / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-09T10:06:34Z (GMT). No. of bitstreams: 1 Pinheiro_TaniaAparecidaLopes_M.pdf: 1079209 bytes, checksum: 7315b8210dfb843979f6a17ba083ed67 (MD5) Previous issue date: 2006 / Resumo: Acetato de medroxiprogesterona (AMP) é um derivado da progesterona que vem sendo usado para contracepção por cerca de 30 milhões de mulheres e também vem aplicado em tratamentos de câncer. Como em alguns casos, AMP gera efeitos colaterais desfavoráveis, sua dosagem deve ser bem controlada. Neste trabalho, foi desenvolvido um método espectrofotométrico para quantificação de AMP em fármacos pela reação com Mo(VI) em meio fortemente ácido. Testes preliminares como avaliação do ponto de fusão e spot test com ácido sulfúrico foram introduzidos para identificar o AMP de outros compostos, como derivados de cortisona que também podem reagir com Mo(VI). A reação foi otimizada a partir da avaliação de algumas variáveis do sistema reacional: tempo e temperatura de aquecimento, solvente e concentração de ácido. Os resultados obtidos indicaram que as melhores condições para o sistema reacional são: solução 9 mol L de H2SO4, 70 minutos de aquecimento a 90 °C e uso de AMP em acetonitrila. Nestas condições, foram obtidas curvas analíticas com a absorbância em 406 nm do produto formado cuja concentração é diretamente proporcional à concentração de AMP na faixa de 5,87x10 a 10,00x10 mg mL, com coeficiente de correlação linear = 0,9972 e limite de detecção = 1,77x10 mg mL. A precisão foi avaliada por intra (repetibilidade) e inter (precisão intermediária) testes, tendo sido obtidos desvios máximos de + 1,9%. Quando comparado com um método de quantificação de AMP em medicamentos comerciais por cromatografia líquida de alta eficiência, os resultados com o método proposto não apresentaram diferenças estatisticamente significativas com 95 % de confiança, indicando bom desempenho do método baseado na reação colorimétrica, que tem favoráveis características de simplicidade instrumental / Abstract: Acetate of medroxiprogesterona (AMP) is one derivative of the progesterone, that have been used used as contraceptive method for about 30 million women. And in treatments of cancer. In some cases, AMP cause favorable collateral effect, therefore its dosage must be well controlled. In this work, a spectrophotometric method for quantification of AMP in pharmaceutical preparation using the reaction with Mo(VI) in strong acid was developed. Preliminary tests as evaluation of the fusing point and spot test with H2SO4 had been introduced in order to identify the AMP from other compounds, as corticoids, that ca also react with Mo(VI). The reaction was optimized from the evaluation of some reaction variable: time and temperature of heating, AMP solvent, acid concentration. The optimized conditions are 9 mol L H2SO4; heating for 70 minutes at 90 °C and acetonirile solvent for AMP. In these conditions, analytical curves of absorbance at 406 nm of the product formed whose concentration is directly proportional to the initial concentration of AMP were obtained from 5,87x10 a 10,00x10 mg mL , with linear coefficient = 0,9972 and detection limit = 1,77x10 mg mL. The precision was evaluated by intra (repeatability) and inter (intermediate precision) tests, having been achieved maximum relative deviation = + 1,9 %. When compared with a HPLC method of quantification of AMP in commercial medicines, the results achieved with this method did give statistical significant differences at 95 % confidence level, indicating good performance of the colorimetric method, which has the advantage of instrumental simplicity / Mestrado / Quimica Analitica / Mestre em Química

Orientador: Luis Guillermo Bahamondes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T05:05:19Z (GMT). No. of bitstreams: 1 Viola_AlexandredeSouza_D.pdf: 11179010 bytes, checksum: b640fe59edc62c7e4656a85dd2252e89 (MD5) Previous issue date: 2011 / Resumo: Objetivos: Avaliar a densidade mineral óssea (DMO) em usuárias por pelo menos um ano e ex-usuárias na pós-menopausa do contraceptivo injetável com acetato de medroxiprogesterona de depósito (AMP-D). Sujeitos e métodos: Foram realizados dois estudos, ambos de corte transversal com usuárias atuais em idade reprodutiva de AMP-D e outro com mulheres na pós-menopausa que usaram AMP-D até a menopausa. Cada usuária foi comparada com uma mulher nunca usuária de AMP-D, da mesma idade (± 1) e mesmo índice de massa corporal (kg/m2) (± 1). Nelas, foram medidas a DMO nas porções distal e ultradistal do rádio do antebraço não dominante pela técnica de DXA (double X-ray absoptiometry). No primeiro estudo foram incorporadas 232 mulheres usuárias do AMP-D e igual número que usavam dispositivo intrauterino (DIU) TCu380A como grupo de controle. As mulheres foram divididas em 5 grupos (1-5) de acordo com o tempo de uso do AMPD: 1-3; 4-6; 7-9; 10-12 e 13-15 anos, respectivamente. No segundo estudo foram incorporadas 79 mulheres com até 5 anos desde a menopausa, sendo 24 ex-usuárias de AMP-D até a menopausa e 55 ex-usuárias de DIU TCu380A também até a menopausa e que tinham avaliado previamente a DMO aos 1-2 e 3 anos após a menopausa. Resultados: No primeiro estudo, a média da idade (± EPM) das usuárias de AMP-D e DIU foi 38,3±0,5 e 38,1±0,57 anos e a média do IMC (índice de massa corporal) (kg/m2) (± EPM) foi de 26,4±0,3 e 26,3±0,3 (kg/m2) para cada grupo, respectivamente. As usuárias de ambos os grupos com pouco tempo de uso dos métodos eram mais jovens que aquelas que os usavam por longo período de tempo, e ambos os grupos apresentavam menor IMC nos primeiros 5 anos de uso. Paridade, cor, prática de atividade física manualmente foram significativamente maiores no grupo das usuárias de DIU (p<0,053, p<0,040 e p<0,012), e o ato de lavar roupas, nas usuárias de AMP-D (p<0,025). Os outros dados sociodemográficos, antropométricos e obstétricos não apresentaram diferenças significantes. As médias da DMO nas regiões distal e ultradistal do rádio foram similares entre as usuárias de AMP-D e DIU, exceto nas usuárias de AMP-D com mais de 13 anos de uso, e que apresentaram DMO significativamente menor (p<0,041 e 0,042, respectivamente). Houve relação direta nos dois grupos entre a DMO e o IMC (kg/m2) e relação inversa entre DMO e idade, nas regiões distal e ultradistal do rádio. No segundo estudo, o tempo de uso de ambos contraceptivos foi de 9,4 ± 3,8 e 14,7 ± 6,2 anos para o AMP-D e DIU, respectivamente. A DMO na região distal nos anos 1; 2-3 e 5-6 após a menopausa foi de 0,426 e 0,445; 0,421 e 0,434 e 0,437 e 0,427 nas usuárias de AMP-D e DIU, respectivamente. Na região ultradistal os valores foram: 0,350 e 0,380; 0,360 e 0,367 e 0,388 e 0,373, respectivamente, todos sem significância estatística. Conclusão: Não foi detectado efeito deletério na DMO do antebraço nas usuárias de AMP-D, com exceção daquelas que o usaram por mais de 13 anos, ou ex-usuárias de AMP-D que estavam na pós-menopausa, quando comparadas às usuárias de DIU. Também foi observada uma relação direta entre DMO e IMC (kg/m2) e indireta entre DMO e idade / Abstract: Objectives: Assess bone mineral density (BMD) in users for at least a year and ex-users in injectable contraceptive postmenopausal with medroxyprogesterone acetate depot (DMPA). Subjects and methods: Two studies have been conducted, both transversal cutting with current users of reproductive age of DMPA and another with postmenopausal women who have used DMPA until menopause. Each user was compared with a woman never using DMPA, the same age (± 1) and the same body mass index (2kg/m) (± 1). In them, were measures the DMO in distal portion and ultra-distal of non-dominant forearm radio technique by DXA (double X-ray absoptiometry). In the first study were incorporated into 232 women users of DMPA and an equal number who used intrauterine device (IUD) TCu380A as control group. Women were divided into 5 groups (1-5) in accordance with the usage time of DMPA: 1 -3; 4-6; 7-9; 10-12 and 13-15 years, respectively. In the second study were incorporated into 79 women with up to 5 years since menopause, being 24 ex-users of DMPA until menopause and 55 ex-users IUD TCu380A also until menopause and who had previously evaluated the DMO to 1-2 and 3 years after menopause. Results: in the first study, the average age (± EPM) of users of DMPA and IUD was 38.1 and 38.3 ± 0.5 ± 0.57 years and average BMI (body mass index) (kg/m2) (± EPM) was 0.3 ± ± 26.3 and 26.4 0.3 (kg/m2) for each group, respectively The users of both groups with little time using the methods were younger than those who used over a long period of time, and both groups had lower BMI in the first 5 years of use. Parity, color, physical activity practice manually were significantly higher in the Group of IUD users (p <0.053, p< 0.040 and p<0.012), and the Act of washing clothes, in the users of DMPA (p < 0.025). The other demographic and anthropometric data partners did not show significant differences obstetric. The average of the DMO in the distal region of the ultra-distal and radio were similar between the users of DMPA and IUD users, except for DMPA with more than 13 years of use with DMO had significantly lower (p < 0.041 and 0.042, respectively). There was no direct relation in two groups between the DMO and the BMI (kg/m2) and inverse relationship between DMO and age, in the region and distal radio ultra-distal. In second study, the time using both contraceptives was 9.4 ± 3.8 and 14.7 ± 6.2 years for DMPA and IUD, respectively. The DMO in distal region in the years 1; 2-3 and 5-6 after menopause was 0.426 and 0.445; 0.434 and 0.421 and 0.437 and requirements in 0.427 DMPA and IUD, respectively. In the ultra-distal region the figures were: 0.350 and 0.380; 0.360 and 0.367 and 0.388 0.373, respectively, and all without statistical significance. Conclusion: No deleterious effects on the DMO requirements in forearm DMPA, with the exception of those who have used for over 13 years, or DMPA ex-users were in post-menopausal women, compared the IUD users. Also we see a direct relationship between the DMO and BMI (kg/m2) and indirectly between DMO and age / Doutorado / Fisiopatologia Ginecológica / Doutor em Ciências da Saúde

Orientadores: Lucia Helena Innocentini Mei, Marcos Akira dÁvila / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T17:34:43Z (GMT). No. of bitstreams: 1 Nista_SilviaVazGuerra_M.pdf: 12755531 bytes, checksum: ed049fb5fccf4416e7f0b8a0290222af (MD5) Previous issue date: 2012 / Resumo: Este projeto foi desenvolvido em duas fases, usando a tecnologia de eletrofiação. A primeira fase foi dedicada a obtenção de membranas eletrofiadas com acetato de celulose, as quais formaram nanofibras que foram carregadas com Sulfato de gentamicina, na segunda fase, para estudos da liberação controlada deste fármaco. Na primeira fase as membranas de nanofibras de Acetato de Celulose, chamadas de nanomembranas, foram produzidas utilizando-se quatro misturas de solventes (Acido Acético/Água (75:25 m/m), Acetona/Água (85:15 m/m), Dimetilacetamida (DMAc)/Acetona (1:2 m/m), Dimetilacetamida/Acetona/Água (32/63/5 m/m)). Usando a ferramenta de planejamento de experimentos (DOE), foram definidos os melhores parâmetros para preparação das membranas nanoestruturadas, em cada sistema de solvente. Três variáveis, sendo a distância entre a agulha e o coletor, a concentração de acetato de celulose na solução e a tensão aplicada, em dois níveis (alto e baixo), foram estudadas em cada sistema. As respostas avaliadas para obtenção da melhor condição, em cada caso, foram o diâmetro médio da fibra obtida e aspecto da membrana formada. Foi realizado também, no sistema de solvente Acido Acético/Água (70:30 m/m), um comparativo entre fiação horizontal, utilizando-se uma taxa de alimentação controlada por uma bomba de infusão, e um sistema vertical onde o fluxo era governado pela gravidade e viscosidade da solução. Um estudo da influencia da taxa de alimentação no diâmetro e aspecto da membrana também foi realizado. Todas as soluções foram avaliadas quanto a sua viscosidade, tensão superficial e condutividade elétrica. Nas soluções de cada sistema de solvente, que apresentaram a melhor condição de processabilidade e melhor membrana, foi realizada uma avaliação do comportamento reológico com a construção de uma curva de Viscosidade versus Taxa de cisalhamento. As melhores membranas obtidas para cada sistema de solvente foram submetidas a um teste de Citotoxicidade para confirmar a biocompatibilidade e sua independência com os resíduos dos solventes utilizados. Na segunda fase utilizaram-se as melhores condições obtidas para cada sistema de solvente e incorporou-se o fármaco Sulfato de Gentamicina em duas concentrações 6 e 60% em massa com base no acetato de celulose. Observou-se a influencia da concentração do fármaco no processo de eletrofiação, no aspecto da membrana formada bem como no diâmetro da nanofibra obtida. A melhor membrana obtida nesta etapa foi produzida a partir do sistema de solventes DMAc/Acetona/Água. As condições de processo utilizadas foram 1 ml/h de vazão, 10 cm de distância entre agulha-coletor e 15 kV de tensão e concentração de acetato de celulose de 15%. Este sistema apresentou-se como um processo bastante viável, não havendo alteração na qualidade da membrana e no processo com a variação da concentração do fármaco. À membrana obtida nestas condições, foi adicionado 50% do fármaco e realizado um teste de liberação com o objetivo de verificar o perfil de liberação do mesmo. Foi realizado um comparativo entre o perfil de liberação desta membrana com o de outras membranas preparadas por casting e com recobrimento de HPMC, Eudragit® L100 e nanofibra eletrofiada de acetato de celulose. O melhor perfil obtido, onde ocorreu uma redução no efeito burst, foi com a membrana revestida com nanofibra, onde foi obtido um ganho de liberação de 9 horas em relação às demais. A melhor membrana obtida também foi submetida a uma análise microbiológica, onde se verificou que o fármaco não perdeu suas propriedades com o processo de eletrofiação / Abstract: This project was developed in two phases, using the technology of electrospinning. The first phase was devoted to obtaining electrospun membranes with cellulose acetate, which formed nanofibers that were loaded with Gentamicin sulphate, in the second phase, for the studies of this drug release. In the first step, these membranes were composed of electrospun nanofibers made of cellulose acetate, here called nanomembranes, using four solvents mixtures (acetic acid/water (75:25 w/w) acetone/water (85:15 w/w), dimethylacetamide(DMAC)/acetone (1:2 w/w), DMAc/acetone/water (32/63/5 w/w). Using the tool for design of experiment (DOE), the best parameters for preparation of nanostructured membranes in each solvent system were fixed. Three variables, such as the distance between the needle and the collector, the concentration of cellulose acetate in solution and the applied voltage, in two levels (high and low), were used in each system. The responses evaluated to obtain the best condition, in each case, were the average diameter of the fiber obtained and the aspect of the membrane formed. In the solvent system formed by acetic acid/water (70:30 w/w), a comparison was carried out between horizontal electrospinning, using an infusion pump to control the feed rate, and a vertical system, whose flow was governed by both gravity and viscosity of the solution. A study of the influence of feed rate on the diameter and aspect of the membranes was done. The viscosity, surface tension and electrical conductivity of all solutions were evaluated. For each system of solvent used, the best parameters of processing ant the best membrane aspect obtained were the chosen for the studies of the rheological behavior of the system by plotting a curve of Viscosity versus Shear rate. The best membranes obtained, for each mixture of solvent used, were submitted to a cytotoxicity test to confirm their biocompatibility and if the residues of any solvent could influence on this test. In the second step of the project, the best conditions obtained for each solvent system were used to electrospun the membranes loaded with gentamicin sulfate in two concentrations, i.e. 6 and 60 wt%, based on cellulose acetate. We observed the influence of the drug concentration in the electrospinning process, as well as the aspect of the membrane formed and the diameters of the nanofibers formed. The best membranes obtained in this step were produced using the solvent system DMAC/acetone/water. The process conditions used were 1 ml/h flow rate, 10 cm distance between needle-collector, 15 kV voltage and 15% cellulose acetate concentration in the solution. This system proved to be a quite feasible process, with no change in the membrane aspect or in the process, for several drug's concentration. To the membrane obtained in these conditions, 50% of the drug was added and the profile of its delivery was observed. A comparison of the releasing profile was also done among this membrane and other membranes prepared by casting and by coating with HPMC, Eudragit ® L100 and electrospun nanofibers of cellulose acetate. The best delivery profile obtained was the membrane coated with nanofiber of acetate solution in DMAC/acetone/water since there was a reduction in the burst effect and a gain in the releasing of 9 hours over the others. The best membrane obtained was also submitted to a microbiological analysis, in which it was verified that the drug did not lose its function during the electrospinning process / Mestrado / Ciencia e Tecnologia de Materiais / Mestre em Engenharia Química