masterThesis
Micropartículas poliméricas à base de xilana e Eudragit® S-100 contendo mesalazina visando à liberação cólon-específica
Fecha
2009-03-10Registro en:
SILVA, Acarilia Eduardo da. Micropartículas poliméricas à base de xilana e Eudragit® S-100 contendo mesalazina visando à liberação cólon-específica. 2009. 104 f. Dissertação (Mestrado em Bioanálises e Medicamentos) - Universidade Federal do Rio Grande do Norte, Natal, 2009.
Autor
Silva, Acarilia Eduardo da
Resumen
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