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Previous issue date: 2009-03-10 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Colon-specific drug delivery systems have attracted increasing attention from the
pharmaceutical industry due to their ability of treating intestinal bowel diseases (IBD), which
represent a public health problem in several countries. In spite of being considered a quite
effective molecule for the treatment of IBD, mesalazine (5-ASA) is rapidly absorbed in the
upper gastrointestinal tract and its systemic absorption leads to risks of adverse effects. The
aim of this work was to develop a microparticulate system based on xylan and Eudragit? S-
100 (ES100) for colon-specific delivery of 5-ASA and evaluate the interaction between the
polymers present in the systems. Additionaly, the physicochemical and rheological properties
of xylan were also evaluated. Initially, xylan was extracted from corn cobs and characterized
regarding the yield and rheological properties. Afterwards, 10 formulations were prepared in
different xylan and ES100 weight ratios by spray-drying the polymer solutions in 0.6N NaOH
and phosphate buffer pH 7.4. In addition, 3 formulations consisting of xylan microcapsules
were produced by interfacial cross-linking polymerization and coated by ES100 by means of
spray-drying in different polymer weight ratios of xylan and ES100. The microparticles were
characterized regarding yield, morphology, homogeneity, visual aspect, crystallinity and
thermal behavior. The polymer interaction was investigated by infrared spectroscopy. The
extracted xylan was presented as a very fine and yellowish powder, with mean particle size
smaller than 40μm. Regarding the rheological properties of xylan, they demonstrated that this
polymer has a poor flow, low density and high cohesiveness. The microparticles obtained
were shown to be spherical and aggregates could not be observed. They were found to present
amorphous structure and have a very high thermal stability. The yield varied according to the
polymer ratios. Moreover, it was confirmed that the interaction between xylan and ES100
occurs only by means of physical aggregation / Sistemas c?lon-espec?ficos t?m atra?do o interesse da ind?stria farmac?utica devido ?
possibilidade de tratarem enfermidades, como as doen?as inflamat?rias intestinais (DII), que
compreendem um problema de sa?de p?blica em muitos pa?ses. Apesar de ser considerada
uma mol?cula bastante eficiente para o tratamento das DII, a mesalazina (5-ASA) ?
rapidamente absorvida no trato gastrintestinal superior e sua absor??o sist?mica leva ?
incid?ncia de s?rios efeitos adversos. Este trabalho teve como objetivos produzir um sistema
polim?rico microparticulado ? base de xilana e Eudragit? S-100 (ES100) para libera??o
c?lon-espec?fica de 5-ASA e avaliar a intera??o entre os pol?meros constituintes do sistema,
al?m de aprofundar a caracteriza??o f?sico-qu?mica e tecnol?gica da xilana. A xilana foi
extra?da a partir de sabugos de milho e caracterizada quanto ao rendimento, granulometria,
cristalinidade, propriedades reol?gicas e comportamento t?rmico. Em seguida, 10
formula??es contendo 5-ASA foram preparadas em diferentes propor??es de xilana e ES100
atrav?s da secagem por aspers?o das solu??es polim?ricas com NaOH 0,6N ou tamp?o-fosfato
pH 7,4, como solvente. Al?m disso, 3 formula??es constitu?das de microc?psulas de xilana
produzidas por reticula??o polim?rica interfacial foram revestidas por ES100 atrav?s de
secagem por aspers?o em diferentes propor??es polim?ricas e empregando-se NaOH 0,6N ou
tamp?o-fosfato pH 7,4, como solvente. As micropart?culas foram avaliadas quanto ao
rendimento, morfologia, granulometria, homogeneidade, aspecto visual, cristalinidade e
comportamento t?rmico. A intera??o entre os pol?meros foi investigada atrav?s da
espectroscopia na regi?o do infravermelho e de an?lises t?rmicas. A xilana extra?da
apresentou-se como um p? muito fino, com tamanho m?dio inferior a 40μm, e com colora??o
opaca levemente amarelada. A avalia??o das propriedades reol?gicas da xilana permitiram a
caracteriza??o desse pol?mero, em seu estado original de p?, como um material de baixa
densidade, fluxo restrito e bastante coesivo. Foram obtidas micropart?culas esf?ricas e sem
presen?a de agregados, com estrutura amorfa, em sua maior parte, e bastate est?veis a
temperaturas elevadas. Al?m disso, confirmou-se que a intera??o entre xilana e ES100 ocorre
apenas por agrega??o f?sica
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13451 |
| Date | 10 March 2009 |
| Creators | Silva, Acarilia Eduardo da |
| Contributors | CPF:38878240400, http://lattes.cnpq.br/6907806915889763, Silva J?nior, Arn?bio Ant?nio, CPF:00840406452, http://lattes.cnpq.br/2593509584288129, Oliveira, Anselmo Gomes de, CPF:59434643872, http://lattes.cnpq.br/9114495952533044, Egito, Eryvaldo S?crates Tabosa do |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncias Farmac?uticas, UFRN, BR, Bioan?lises e Medicamentos |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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