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Maria Esperanza Cortes SeguraRuben Dario Sinisterra MillanMario Julio Avila-CamposFrederic Jean Georges FrezardKarina Imaculada Rosa Teixeira2019-08-14T10:49:32Z2019-08-14T10:49:32Z2008-04-25http://hdl.handle.net/1843/MECS-7E7GA2A formacao de compostos de inclusao de clorexidina para a liberacao controlada de antimicrobianos tem mostrado diminuicao das concentracoes terapeuticas efetivas. Contudo, pouco se sabe sobre o mecanismo de acao desses compostos de inclusao em relacao aos microrganismos. Dessa maneira o objetivo deste trabalho foi preparar ecaracterizar compostos de inclusao e estudar o mecanismo de acao antimicrobiana dos compostos de inclusao de clorexidina: beta-ciclodextrina (Cx:À-cd) nas celulas bacterianas e fungica. Foram preparados compostos de inclusao Cx:À-cd em 1:1; 1:2;1:3 e 1:4 proporcoes molares, pelo metodo de liofilizacao. Foi feita a caracterizacao fisico-quimica dos compostos por Difratometria de raios-X, Analise termica e Ressonancia Magnetica Nuclear. Os testes de substantividade dos compostos de inclusao de (Cx:À-cd) foram realizados a partir de geis a base de hidroxi-metil-propilcelulose.A Concentracao Inibitoria Minima (CIM) da Cx:À-cd foi determinada paraAggregatibacter actinomycetemcomitans (A.a) e Candida albicans (C.a). A analise dos mecanismos de acao relacionados a membrana foi feita por microscopia eletronica de varredura (MEV), microscopia de forca atomica (MFA) dos microrganismos cultivados e pela Tecnica MQE (Metodo de Quantificacao do Esterol). A CMI para os compostosde inclusao foi de 2 [g/mL para A.a e 1 [g/mL para C.a em todos os grupos. Na MEV foi possivel avaliar a morfologia celular e dos farmacos. No grupo da Cx foram observadas estruturas disformes sugestivas de celulas bacterianas rodeadas por particulas menores semelhantes aos compostos. A desorganizacao celular foi significativamente maior com o aumento da proporcao de ciclodextrina nos compostos, sendo que nas razoes molares 1:3 e 1:4 foram observados grandes agregados mistos de 15 Cx:À-cd e restos bacterianos em contraste com o grupo Cx onde o microorganismo apresentou-se com estrutura coco - bacilar caracteristica ou formando colonias. Para o teste do MQE nos grupos 1:3 e 1:4 o ergosterol ficou significativamente diminuido, com variacao de mais de 100% quando comparado as outras substancias testadas. AMFA mostrou defeitos na membrana resultado da solubilizacao de lipideos na regiao dos dominios dos farmacos testados. O aumento da solubilizacao dos dominios membranares e diretamente proporcional a concentracao de beta- ciclodextrina sendo mais evidente na razao 1:2.Conclui-se que a ciclodextrina aumenta as ligacoes com a membrana celular dos compostos de inclusao de Cx:À-cd em nanoagregados, possivelmente influenciadas pela combinacao de sinergica de fatores como interacoes eletrostaticas (entre as cargas negativas da membrana e positivas da clorexidina), tensao superficial, espessura da parede celular.The formation of inclusion compounds of chlorhexidine for the controlled release of antimicrobials has shown decreasing in therapeutic concentrations effective. However, a lack of studies has been published about the mechanism which was inclusion compounds increase cellular permeability through the microorganisms membrane. Thus the objective of this work was to prepare and characterize inclusion compounds and study the mechanism of action of antimicrobial compounds for inclusion of chlorhexidine:beta-cyclodextrin (Cx: - cd) against the bacterial and fungal cells for Inclusion compounds have been in various prepared proportions molars by the method of freeze-dryed. The release of the drug was performed from samples for 10 days, bovine teeth were included in paraffin blocks, in the portion corresponding to the root dentin were opened windows of 4x 8mm was 75 mg gels based on hydroxy-metil-propyl cellulose at concentration 128 µg/mL. The gel the compounds tested in 128 were left in contact with the surface for 5 minutes after which the teeth were washed in distilled water and left in plastic pots containing 1 mL buffer solution which was withdrawn and replaced daily. The samples were subjected to UV-spectrophotometry of a visible at wavelength of 275 nm. The concentration of chlorhexidine released daily from the samples was obtained and the results submitted to the ANOVA statistical test. The Minimum Inhibitory Concentration (MIC) of Cx: - cd was determined to Aggregatibacter actynomicetemcomitans (A.a.) and Candida albicans (C.a.). The analysis of the mechanisms of action related to the membrane was made by scanning electron microscopy (SEM), atomic force microscopy (MFA) and transmission electron microscopy (MET) of microorganisms grown and the Technical SQM consisting (Sterol Quantification Method) in the extraction of ergosterol from fungal cell wall in contact with the 1µg / mL for compound. The MIC was 2 µg/ mL for Ca in all groups. For A.a and SEM could assess the cellular morphology and drugs. In the group of Cx was observed structures amorphous suggestive of bacterial cells surrounded by smaller particles similar to those compounds. The disorganization cell was significantly higher with the increase in the proportion of cyclodextrin compound, and that the molars 1:3 and 1:4 were observed large aggregates mixed of Cx bacterial remains in contrast with the group Cx where the microorganism presented a typical structure of coccus -bacilli characteristic or forming colonies. For the test of SQM groups 1:3 and 1:4 in the ergosterol was significantly decreased, with a range of more than 100% when compared to other substances tested. The MFA showed defects on the outcome of the solubilization of membrane lipids in the region of the areas of the drugs tested. Increasing the solubilization of the membranes areas is directly proportional to concentration of beta-cyclodextrin being more evident in the ratio 1:2. In conclusion the cyclodextrin increases the bondings with the cell membrane of the compounds for inclusion cd in nanoagregates possibly influenced: by the synergistic combination of factors such as electrostatic interactions, surface tension, thickness of the cell wall.Universidade Federal de Minas GeraisUFMGMicroscopia eletrônica de varreduraClorexidinaMembrana celularClorexidina/farmacologia DeCsMicroscopia de força atômicaclorexidinananoagregadosciclodextrinaEstudo das alterações da membrana celular de microrganismos por compostos de inclusão de clorexidina: beta-ciclodextrina em diferentes proporções molares usando Microscopia de Força Atômica e Microscopia Eletrônica de Varredurainfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisinfo:eu-repo/semantics/openAccessporreponame:Repositório Institucional da UFMGinstname:Universidade Federal de Minas Gerais (UFMG)instacron:UFMGORIGINALdissertao_completa.pdfapplication/pdf6383981https://repositorio.ufmg.br/bitstream/1843/MECS-7E7GA2/1/dissertao_completa.pdfb566e3aa4b8500e198be4d398bed09aaMD51TEXTdissertao_completa.pdf.txtdissertao_completa.pdf.txtExtracted texttext/plain158602https://repositorio.ufmg.br/bitstream/1843/MECS-7E7GA2/2/dissertao_completa.pdf.txt2dff5a4bfb6ba15f958d55c546144596MD521843/MECS-7E7GA22019-11-14 09:34:01.493oai:repositorio.ufmg.br:1843/MECS-7E7GA2Repositório InstitucionalPUBhttps://repositorio.ufmg.br/oaiopendoar:2019-11-14T12:34:01Repositório Institucional da UFMG - Universidade Federal de Minas Gerais (UFMG)false
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