• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 9
  • 9
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Pharmakokinetik von Olsalazin beim Pferd

Strauhs, Peter 14 June 2005 (has links) (PDF)
Pharmakokinetische Grundlagenuntersuchung nach oraler Applikation des Prodrugs Olsalazin im Hinblick auf dessen mögliche therapeutische Anwendung bei unspezifischen entzündlichen Dickdarmerkrankungen des Pferdes (z.B.Typhlokolitis). / Basic studies of the pharmakokinetics of olsalazine following oral administration to horses in order to prepare a possible therapeutic use of this drug for the treatment of inflammatory bowel diseases of horses (e.g. typhlocolitis).
2

Desenvolvimento de metodologia espectrofotométrica como alternativa para determinação do ácido 5-aminosalicílico em medicamentos / Development of spectrophotometric methodology as an alternative for the determination of 5-aminosalicilic acid in medicines

Corrêa, André Coradini 07 March 2018 (has links)
Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2018-05-15T14:18:02Z No. of bitstreams: 2 André Coradini Corrêa.pdf: 994260 bytes, checksum: 895aa0122b211cc9de09ddb7f9a3cecb (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-05-15T14:18:02Z (GMT). No. of bitstreams: 2 André Coradini Corrêa.pdf: 994260 bytes, checksum: 895aa0122b211cc9de09ddb7f9a3cecb (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The development of new analytical methodologies is essential to create alternatives to the methods described in the pharmacopoeias, either for identification or quantification of drugs. The literature shows few methods of quantification of 5-aminosalicylic acid (5-ASA) in pharmaceutical forms, being the methodology most used by CLAE (High Performance Liquid Chromatography), which makes the procedure expensive and even unviable in certain sectors. Thus, it is justified the research by fast, efficient and low-cost methods for the analysis of this drug. This dissertation aimed to use the spectrophotometry technique for the determination of 5-aminosalicylic acid in different pharmaceutical forms, based on the formation reaction of a colored complex formed between 5-ASA and Fe3+ ions, which is known as the Trinder. Chapter 1 of this dissertation describes the methodology developed, as well as the results of this research, together with the relevant discussions. Experimental design (ED) and response surface methodology (RSM) were carried out in order to reduce the number of experiments and achieve the best conditions for complex absorbance procedure. Three factors at two levels were studied: 5-ASA concentration (150 mg/L; 275 mg/L and 400 mg/L), FeCl3 concentration (100 mg/L; 200 mg/L and 300 mg/L) and volume ratio (1:2; 1:1 and 2:1) between the amounts of 5-ASA and FeCl3. The developed method showed satisfactory values for linearity, precision and accuracy. The different drug formulations containing 5-ASA presented values that were in agreement with those specifications in the package. This spectrophotometric methodology proved to be low-cost, simple and fast to determine 5-ASA in pharmaceutical formulations. / O desenvolvimento de novas metodologias analíticas é essencial para criar alternativas aos métodos descritos nas farmacopeias, seja para identificação ou quantificação de fármacos. A literatura mostra poucos métodos de quantificação do ácido 5-aminosalicílico (5-ASA) em formas farmacêuticas. É considerada a metodologia mais utilizada, feita por CLAE (Cromatografia Líquida de Alta Eficiência), o que torna caro o procedimento e até inviável em determinados setores. Dessa forma, justifica-se a pesquisa por métodos rápidos, eficientes e de baixo custo para análise desse fármaco. Assim, esta dissertação teve como objetivo utilizar a técnica de espectrofotometria para a determinação de ácido 5-aminosalicílico em diferentes formas farmacêuticas, baseando-se na reação de formação de um complexo colorido formado entre 5-ASA e íons Fe3+, a qual é conhecida como técnica de Trinder. No Capítulo 1 dessa dissertação está descrita a metodologia desenvolvida, bem como os resultados dessa pesquisa, juntamente com as discussões pertinentes. O delineamento experimental (DOE) e a metodologia de superfície de resposta (RSM) foram realizados com o objetivo de reduzir o número de experimentos e obter as melhores condições para os procedimentos de medidas de absorbância do complexo. Foram estudados três fatores em dois níveis: concentração de 5-ASA (150 mg/L; 275 mg/L e 400 mg/L), concentração de FeCl3 (100 mg/L; 200 mg/L e 300 mg/L) e proporção de volume (1:2; 1:1 e 2:1) entre as quantidades de 5-ASA e FeCl3. O método desenvolvido apresentou valores satisfatórios de linearidade, precisão e exatidão. As diferentes formulações de drogas contendo 5-ASA apresentaram valores concordantes com os das especificações contidas na embalagem. A metodologia espectrofotométrica aplicada foi de baixo custo, simples e rápida para a determinação de 5-ASA em formulações farmacêuticas.
3

Pharmakokinetik von Olsalazin beim Pferd

Strauhs, Peter 10 January 2003 (has links)
Pharmakokinetische Grundlagenuntersuchung nach oraler Applikation des Prodrugs Olsalazin im Hinblick auf dessen mögliche therapeutische Anwendung bei unspezifischen entzündlichen Dickdarmerkrankungen des Pferdes (z.B.Typhlokolitis). / Basic studies of the pharmakokinetics of olsalazine following oral administration to horses in order to prepare a possible therapeutic use of this drug for the treatment of inflammatory bowel diseases of horses (e.g. typhlocolitis).
4

Aplikace mesalazinu do peritoneální dutiny potkana

Hönigová, Kateřina January 2019 (has links)
The objective of this diploma thesis was to determine the influence of the application of 5-aminosalicylic acid (5-ASA) in the peritoneal cavity on the initiation and course of the inflammatory reaction. For these purposes, the rat was chosen as the model animal on which the model of intraperitoneal lavage was applied. The rat’s peritoneal cavity is easily accessible and reflects the functions and reactions of the immune system. For the purposes of the experiment, the rats were divided into 3 groups; in the first group, the peritoneal cavity was assessed in its physiological condition, without any prior application of the substance. PBS was applied to the second group of rats, and the evaluation of the absolute numbers of cells followed after 4 and 24 hours using the Bürker counting chamber and optical microscopy. In the last group, mesalazine was applied, the exposure of which was 4 hours for one half of the group and 24 hours for the other. These time intervals were followed by the evaluation of the absolute number of cells. In order to determine the differential numbers of cells for all the samples, the coated glasses were coloured and evaluated. The greatest statistically relevant difference was identified in the case of the neutrophil population, where the neutrophil share increased from 0-5 % in the intact cavity to up to 35 % in the cavity after the PBS application. Out of all the experimental groups, the population of lymphocytes was relatively stable; the share of macrophages was, statistically, considerably lower for the groups after the mesalazine application. These results indicate that the application of PBS as an inert substance did not cause such a major reaction regarding the influx of neutrophils as the application of 5-ASA.
5

Les systèmes microparticulaires pour la libération colonique / Multiparticulate colon drug delivery systems

Bautzova, Tereza 17 September 2012 (has links)
La maladie de Crohn et la rectocolite hémorragique font partie des maladies inflammatoires chroniques de l'intestin (MICI). Le principal objectif des traitements anti-inflammatoires est de favoriser la délivrance du principe actif localement, spécifiquement sur les zones enflammées et de limiter les effets indésirables. Ainsi, plusieurs systèmes à libération colonique de molécules actives ont été développés. Parmi eux, les pellets présentent de nombreux avantages par rapport aux formes solides unitaires conventionnelles. Dans un premier temps, des pellets comptant une substance anti-inflammatoire naturelle et nutritive, la rutine, ont été développés. L'intérêt de cette molécule est de réduire considérablement les effets secondaires qui constituent un véritable problème dans les traitements actuels des MICI. Les pellets ont été enrobé avec les polysaccharides naturels se dégradant avec la flore colonique. Les études in vitro ont démontré une libération minimale du principe actif au niveau de l'estomac et du petit intestin. Par contre, une libération rapide et totale a été observée lors de l'exposition des pellets dans les conditions du milieu colonique. Les résultats des tests in vivo ont démontré que la rutine a atténué considérablement l'inflammation au niveau de colon et les pellets enrobés ont été aussi efficaces que les pellets d'acide 5-aminosalicylique (5-ASA) commercialisés. L'administration orale de rutine via les pellets enrobés et préparés avec le chitosan semble être une approche prometteuse, permettant la libération du principe actif au niveau des zones enflammées, pour le traitement des MICI tout en réduisant les effets secondaires. Le deuxième but de notre travail était d'élucider l'impact du chitosan, un polymère mucoadhésif, sur l'efficacité thérapeutique. Les pellets de 5-ASA ont été préparés à partir de cellulose microcristalline avec ou sans chitosan. Un enrobage constitué d'un polymère pH dépendant,1' Eudragit® FS, a ensuite été réalisé autour du noyau. Les tests de dissolution ont montré que le principe actif n'était pas libéré du pellet après 2 h en milieu acide. En revanche,la libération était rapide dans un milieu simulant l'environnement colonique. Les tests ex vivo avec les pellets contenant le chitosan ont montré des propriétés mucoadhésives importantes qui ont été confirmées par la concentration élevée du métabolite de 5-ASA dans les tissus coloniques des rats. De plus, nous avons a démontré que les pellets permettaient d'atténuer de façon significative l'inflammation du côlon. Ainsi, les pellets bioadhésifs enrobés possèdent des propriétés bénéfiques supplémentaires pour la libération du 5-ASA au niveau du côlon par rapport à des formes multidoses commercialisées pour le traitement des MICI. / Crohn's disease and ulcerative colitis are two related but distinct chronic inflammatory disorders of gastrointestinal tract (GIT), commonly denoted as inflammatory bowel disease(IBD). The main goal of the anti-inflammatory treatment of this disorder is to achieve maximal drug concentration in inflamed area and reduce systemic adverse effects. For this purpose several colon-spécifie drug delivery systems have been investigated. In addition, the design of pellets as oral drug delivery systems may provide many advantages over single unit preparations and thus improve patient compliance. It is well known that most existing treatments of IBD are associated with significant side effects and for this reason the formulation with a " food like " composition was designed. In the first part of our study, therapeutic efficiency of rutin/chitosan pellets with coatings based on natural polysaccharides degraded by colonie microbiota compared to commercialized 5-aminosalicylic acid (5-ASA) pellets was investigated. Release profiles ofcoated pellets showed a minimal drug release in simulated stomach and small intestine following by rapid drug release upon exposure to the colonie fluid. The results from in vivo testing showed that rutin attenuated efficiently inflammation in the colon and coated pellets were as effective as 5-ASA pellets in mitigating experimental colitis. The studies demonstrated that rutin administration via chitosan core coated pellets seems to be apromising approach for colon-specific delivery since they could interact easily with the mucin layer and deliver drug especially to the inflamed colonie area to relieve symptoms of IBD omitting side effects related to conventional treatment. The second objective of this thesis was to explore the impact of additional mucoadhesive polymer chitosan in the pellets core on the therapeutic efficiency. For this purpose, 5-ASA loaded pellets were produced by extrusion/spheronisation method and subsequently coated with pH-sensitive polymer Eudragit® FS. No drug release at pH 1.2within 2 h, and release as intended in the simulated distal ileum and colon was observed. Chitosan-core pellets showed efficient mucoadhesive properties in ex vivo bioadhesion testing which were also confirmed by increased concentration of 5-ASA metabolite in the colonie tissues in rats. The pellets were tested in preexisting colitis and the results revealed significant attenuation of the colonie inflammation. We can conclude, that bioadhesive chitosan-corepellets showed additional beneficial properties for colonie 5-ASA delivery in the treatment of IBD over marketed dosage formulation.
6

Les systèmes microparticulaires pour la libération colonique

Bautzova, Tereza 17 September 2012 (has links) (PDF)
La maladie de Crohn et la rectocolite hémorragique font partie des maladies inflammatoires chroniques de l'intestin (MICI). Le principal objectif des traitements anti-inflammatoires est de favoriser la délivrance du principe actif localement, spécifiquement sur les zones enflammées et de limiter les effets indésirables. Ainsi, plusieurs systèmes à libération colonique de molécules actives ont été développés. Parmi eux, les pellets présentent de nombreux avantages par rapport aux formes solides unitaires conventionnelles. Dans un premier temps, des pellets comptant une substance anti-inflammatoire naturelle et nutritive, la rutine, ont été développés. L'intérêt de cette molécule est de réduire considérablement les effets secondaires qui constituent un véritable problème dans les traitements actuels des MICI. Les pellets ont été enrobé avec les polysaccharides naturels se dégradant avec la flore colonique. Les études in vitro ont démontré une libération minimale du principe actif au niveau de l'estomac et du petit intestin. Par contre, une libération rapide et totale a été observée lors de l'exposition des pellets dans les conditions du milieu colonique. Les résultats des tests in vivo ont démontré que la rutine a atténué considérablement l'inflammation au niveau de colon et les pellets enrobés ont été aussi efficaces que les pellets d'acide 5-aminosalicylique (5-ASA) commercialisés. L'administration orale de rutine via les pellets enrobés et préparés avec le chitosan semble être une approche prometteuse, permettant la libération du principe actif au niveau des zones enflammées, pour le traitement des MICI tout en réduisant les effets secondaires. Le deuxième but de notre travail était d'élucider l'impact du chitosan, un polymère mucoadhésif, sur l'efficacité thérapeutique. Les pellets de 5-ASA ont été préparés à partir de cellulose microcristalline avec ou sans chitosan. Un enrobage constitué d'un polymère pH dépendant,1' Eudragit® FS, a ensuite été réalisé autour du noyau. Les tests de dissolution ont montré que le principe actif n'était pas libéré du pellet après 2 h en milieu acide. En revanche,la libération était rapide dans un milieu simulant l'environnement colonique. Les tests ex vivo avec les pellets contenant le chitosan ont montré des propriétés mucoadhésives importantes qui ont été confirmées par la concentration élevée du métabolite de 5-ASA dans les tissus coloniques des rats. De plus, nous avons a démontré que les pellets permettaient d'atténuer de façon significative l'inflammation du côlon. Ainsi, les pellets bioadhésifs enrobés possèdent des propriétés bénéfiques supplémentaires pour la libération du 5-ASA au niveau du côlon par rapport à des formes multidoses commercialisées pour le traitement des MICI.
7

Potencial terapêutico de sistemas matriciais do ácido 5-aminossalicílico no tratamento de doenças inflamatórias intestinais: revisão sistemática / Therapeutic potential of 5-aminossalicylic acid matrix systems in the treatment of inflammatory bowel diseases

Simoni, Suelen Eloise 09 March 2018 (has links)
Submitted by Rosangela Silva (rosangela.silva3@unioeste.br) on 2018-05-14T14:55:58Z No. of bitstreams: 2 Suelen Eloise Simoni.pdf: 965660 bytes, checksum: 4e663d56433a3c0d625376f602d694d5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-05-14T14:55:58Z (GMT). No. of bitstreams: 2 Suelen Eloise Simoni.pdf: 965660 bytes, checksum: 4e663d56433a3c0d625376f602d694d5 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-03-09 / The development of new technologies for the treatment of inflammatory bowel diseases, such as 5-aminosalicylic acid (5-ASA) multi matrix, becomes increasingly important because they are alternatives in unsuccessful treatments or even influence adaptation to a simpler dosing regimen. However, there is no clear conclusion as to its superiority or efficacy in modified release coated tablets, which are applied in clinical treatment protocols, nor on their safety and tolerability. For this reason, the objective of this dissertation was to perform a systematic review, searching through predefined keywords in database (Pubmed, Science Direct, Embase, Scopus, Web of Science and Clinical Trials) and also by research manual, from March 2016 to December 2017, studies comparing matrix technology with delayed release coated tablets in order to gather evidence that showed the equivalence or superiority of efficacy of this formulation in the parameters of clinical and endoscopic remission in patients suffering from of ulcerative colitis. In all, three studies fit into the inclusion criteria and were added to this study, all of them being a multicenter, double-blind, randomized methodological design, with matrix tablet concentrations varying from 1.2 g to 4.8 g daily, while the dose range of the coated tablets ranged from 800 mg to 2.4 g divided in two to three administrations daily. In summary, the efficacy of the two dosage forms is extremely similar in endoscopic remission parameters, however, when clinical remission is considered, the results indicate that better indices are achieved in the use of matrix technology, regardless of the concentration used. / O desenvolvimento de novas tecnologias para o tratamento de doenças inflamatórias intestinais, como o ácido 5-aminossalicílico (5-ASA) em sua forma matricial torna-se cada vez mais importante, porque surgem como alternativas em tratamentos sem sucesso ou ainda, influenciam na adaptação a um esquema posológico mais simples. No entanto, não se tem uma conclusão clara sobre a sua superioridade ou equiparação de eficácia aos comprimidos revestidos de liberação modificada, os quais são aplicados em protocolos clínicos de tratamento, nem tampouco sobre a sua segurança e tolerabilidade. Por essa razão, o objetivo dessa dissertação foi realizar uma revisão sistemática, buscando-se através de palavras-chave pré-definidas em base de dados (Pubmed, Science Direct, Embase, Scopus, Web Of Science e Clinical Trials) e também por pesquisa manual, de março de 2016 a dezembro de 2017, trabalhos que comparassem a tecnologia matricial com comprimidos revestidos de liberação retardada, a fim de reunir evidências que demonstrassem a equiparação ou superioridade de eficácia dessa formulação nos parâmetros de remissão clínica e endoscópica nos pacientes que sofrem de colite ulcerativa. No total, três estudos se enquadraram nos critérios de inclusão e foram adicionados a esse trabalho, sendo todos eles de desenho metodológico multicêntrico, duplo-cego e randomizado, tendo as concentrações dos comprimidos matriciais variando de 1,2 g a 4,8 g diários, enquanto que a variação das doses dos comprimidos revestidos variou de 800 mg a 2,4 g divididos em duas a três administrações diárias. Em síntese, a eficácia das duas formas farmacêuticas mostra-se extremamente semelhante nos parâmetros de remissão endoscópica, no entanto, quando se considera a remissão clínica os resultados apontam que melhores índices são alcançados na utilização da tecnologia matricial, independente da concentração utilizada do medicamento.
8

Les systèmes microparticulaires pour la libération colonique / Multiparticulate colon drug delivery systems

Bautzova, Tereza 17 September 2012 (has links)
La maladie de Crohn et la rectocolite hémorragique font partie des maladies inflammatoires chroniques de l'intestin (MICI). Le principal objectif des traitements anti-inflammatoires est de favoriser la délivrance du principe actif localement, spécifiquement sur les zones enflammées et de limiter les effets indésirables. Ainsi, plusieurs systèmes à libération colonique de molécules actives ont été développés. Parmi eux, les pellets présentent de nombreux avantages par rapport aux formes solides unitaires conventionnelles. Dans un premier temps, des pellets comptant une substance anti-inflammatoire naturelle et nutritive, la rutine, ont été développés. L'intérêt de cette molécule est de réduire considérablement les effets secondaires qui constituent un véritable problème dans les traitements actuels des MICI. Les pellets ont été enrobé avec les polysaccharides naturels se dégradant avec la flore colonique. Les études in vitro ont démontré une libération minimale du principe actif au niveau de l'estomac et du petit intestin. Par contre, une libération rapide et totale a été observée lors de l'exposition des pellets dans les conditions du milieu colonique. Les résultats des tests in vivo ont démontré que la rutine a atténué considérablement l'inflammation au niveau de colon et les pellets enrobés ont été aussi efficaces que les pellets d'acide 5-aminosalicylique (5-ASA) commercialisés. L'administration orale de rutine via les pellets enrobés et préparés avec le chitosan semble être une approche prometteuse, permettant la libération du principe actif au niveau des zones enflammées, pour le traitement des MICI tout en réduisant les effets secondaires. Le deuxième but de notre travail était d'élucider l'impact du chitosan, un polymère mucoadhésif, sur l'efficacité thérapeutique. Les pellets de 5-ASA ont été préparés à partir de cellulose microcristalline avec ou sans chitosan. Un enrobage constitué d'un polymère pH dépendant,1' Eudragit® FS, a ensuite été réalisé autour du noyau. Les tests de dissolution ont montré que le principe actif n'était pas libéré du pellet après 2 h en milieu acide. En revanche,la libération était rapide dans un milieu simulant l'environnement colonique. Les tests ex vivo avec les pellets contenant le chitosan ont montré des propriétés mucoadhésives importantes qui ont été confirmées par la concentration élevée du métabolite de 5-ASA dans les tissus coloniques des rats. De plus, nous avons a démontré que les pellets permettaient d'atténuer de façon significative l'inflammation du côlon. Ainsi, les pellets bioadhésifs enrobés possèdent des propriétés bénéfiques supplémentaires pour la libération du 5-ASA au niveau du côlon par rapport à des formes multidoses commercialisées pour le traitement des MICI. / Crohn's disease and ulcerative colitis are two related but distinct chronic inflammatory disorders of gastrointestinal tract (GIT), commonly denoted as inflammatory bowel disease(IBD). The main goal of the anti-inflammatory treatment of this disorder is to achieve maximal drug concentration in inflamed area and reduce systemic adverse effects. For this purpose several colon-spécifie drug delivery systems have been investigated. In addition, the design of pellets as oral drug delivery systems may provide many advantages over single unit preparations and thus improve patient compliance. It is well known that most existing treatments of IBD are associated with significant side effects and for this reason the formulation with a " food like " composition was designed. In the first part of our study, therapeutic efficiency of rutin/chitosan pellets with coatings based on natural polysaccharides degraded by colonie microbiota compared to commercialized 5-aminosalicylic acid (5-ASA) pellets was investigated. Release profiles ofcoated pellets showed a minimal drug release in simulated stomach and small intestine following by rapid drug release upon exposure to the colonie fluid. The results from in vivo testing showed that rutin attenuated efficiently inflammation in the colon and coated pellets were as effective as 5-ASA pellets in mitigating experimental colitis. The studies demonstrated that rutin administration via chitosan core coated pellets seems to be apromising approach for colon-specific delivery since they could interact easily with the mucin layer and deliver drug especially to the inflamed colonie area to relieve symptoms of IBD omitting side effects related to conventional treatment. The second objective of this thesis was to explore the impact of additional mucoadhesive polymer chitosan in the pellets core on the therapeutic efficiency. For this purpose, 5-ASA loaded pellets were produced by extrusion/spheronisation method and subsequently coated with pH-sensitive polymer Eudragit® FS. No drug release at pH 1.2within 2 h, and release as intended in the simulated distal ileum and colon was observed. Chitosan-core pellets showed efficient mucoadhesive properties in ex vivo bioadhesion testing which were also confirmed by increased concentration of 5-ASA metabolite in the colonie tissues in rats. The pellets were tested in preexisting colitis and the results revealed significant attenuation of the colonie inflammation. We can conclude, that bioadhesive chitosan-corepellets showed additional beneficial properties for colonie 5-ASA delivery in the treatment of IBD over marketed dosage formulation.
9

Micropart?culas polim?ricas ? base de xilana e Eudragit? S-100 contendo mesalazina visando ? libera??o c?lon-espec?fica

Silva, Acarilia Eduardo da 10 March 2009 (has links)
Made available in DSpace on 2014-12-17T14:16:25Z (GMT). No. of bitstreams: 1 AcariliaES_Dissert_01.pdf: 1640327 bytes, checksum: 9c4568aff953d538d26000691eb0407d (MD5) 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

Page generated in 0.0299 seconds