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Previous issue date: 2008-12-16 / This work aimed to develop a suitable magnetic system for administration by the oral route. In addition to that, it was intended to review the current uses of magnetic systems and the safety related to magnetic field exposure. Methods:
Coprecipitation and emulsification/crosslinking were carried out in order to synthesize magnetite particles and to coat them, respectively. Results: According to literature
review, it was found that magnetic particles present several properties such as magnetophoresis in magnetic field gradient, production of a surrounding magnetic field, and heat generation in alternated magnetic field. When the human organism is exposed to magnetic fields, several interaction mechanisms come into play. However, biological tissues present low magnetic susceptibility. As a result, the
effects are not so remarkable. Concerning the development of a magnetic system for oral route, uncoated magnetite particles did undergo significant dissolution at gastric
pH. On the other hand, such process was inhibited in the xylan-coated particles. Conclusions: Due to their different properties, magnetic systems have been widely used in biosciences. However, the consequent increased human exposure to magnetic fields has been considered relatively safe. Concerning the experimental work, it was developed a polymer-coated magnetic system. It may be very promising for administration by the oral route for therapy and diagnostic applications as dissolution at gastric pH hardly took place / Realizar um trabalho multidisciplinar a fim de revisar os usos biom?dicos de sistemas magn?ticos, analisar os aspectos sobre a seguran?a relativa ? exposi??o de organismos vivos a campos magn?ticos e desenvolver um sistema magn?tico apropriado para administra??o por via oral. Metodologia: Inicialmente, part?culas magn?ticas foram produzidas pela coprecipita??o de sais de ferro no meio alcalino. A etapa seguinte consistiu no processo de emulsifica??o/reticula??o interfacial realizado a fim de produzir part?culas magn?ticas revestidas por xilana. Resultados: Constata-se que as part?culas magn?ticas apresentam diversas propriedades tais como mobilidade magnetofor?tica em gradiente de campo magn?tico, produ??o de um campo magn?tico capaz de influenciar a regi?o em sua volta e gera??o de calor em campo magn?tico alternado. A exposi??o a campos magn?ticos implica em diversos mecanismos de intera??o, mas os efeitos tendem a ser m?nimos em virtude da baixa susceptibilidade magn?tica dos tecidos. Quanto ao uso
de part?culas de magnetita por via oral, os dados sobre a caracteriza??o das amostras e os resultados do teste de dissolu??o in vitro em pH g?strico demonstraram a viabilidade do m?todo de revestimento apresentado para proteger as part?culas de magnetita da dissolu??o g?strica. Conclus?es: Devido ?s suas diferentes propriedades, os sistemas
magn?ticos t?m encontrado ampla aplicabilidade em ci?ncias biom?dicas, sendo o conseq?ente aumento da exposi??o humana a campo considerado relativamente seguro.
Experimentalmente, foi desenvolvido um sistema magn?tico promissor para administra??o por via oral, que poder? encontrar aplicabilidade como marcador de motilidade intestinal, contraste para resson?ncia nuclear magn?tica ou para a vetoriza??o de f?rmacos
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/13144 |
| Date | 16 December 2008 |
| Creators | Silva, Amanda Karine Andriola |
| Contributors | CPF:38878240400, http://lattes.cnpq.br/6907806915889763, Oliveira, Anselmo Gomes de, CPF:59434643872, http://lattes.cnpq.br/9114495952533044, Magalh?es, Nereide Stella Santos, CPF:34939610497, Silva J?nior, Arn?bio Ant?nio, CPF:00840406452, http://lattes.cnpq.br/2593509584288129, Balaban, Ros?ngela de Carvalho, CPF:65946499734, http://lattes.cnpq.br/7711521318854102, Egito, Eryvaldo S?crates Tabosa do |
| Publisher | Universidade Federal do Rio Grande do Norte, Programa de P?s-Gradua??o em Ci?ncias da Sa?de, UFRN, BR, Ci?ncias da Sa?de |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/embargoedAccess |
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