Desenvolvimento de hidrogéis bionanocompósitos ativos baseados em amido e alginato com potencial aplicação na agricultura e na biomedicina
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Data
2020-05-15
Autores
Fernandes, Renan da Silva [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A problemática referente as implicações oriundas das recorrentes aplicações de medicamentos e/ou defensivos agrícolas em altas concentrações nos seres vivos e no meio ambiente, motivaram os autores a desenvolverem sistemas poliméricos a base de hidrogéis bionanocompósitos capazes de minimizar os impasses referente a contaminação e efeitos colaterais a partir de uma liberação controlada dos fármacos e herbicida propostos. Com isso, os hidrogéis foram preparados a partir de polissacarídeos e nanoestruturas inorgânicas naturais nos quais foram reticulados com diferentes íons (Mn2+, Zn2+ ou Ca2+). Os hidrogéis foram caracterizados de acordo com suas propriedades hidrofílicas, estruturais, espectroscópicas, morfológicas, térmicas, de sorção e dessorção de fármaco ou herbicida. Em relação ao grau de intumescimento e adsorção do herbicida, os hidrogéis reticulados com Mn2+ apresentaram os mais altos valores, isso porque este íon possui a menor raio iônico em relação ao Zn2+ e Ca2+. Por outro lado, a adição das nanoestruturas (argila ou zeólita) diminuíram o grau de intumescimento dos hidrogéis, pois aumentaram a densidade de reticulação, sendo esse efeito confirmado pela análise de MEV. Em contrapartida, a presença das nanoestruturas aumentou a quantidade do herbicida paraquat adsorvida, devido à presença dos grupamentos polares que possibilitam e interação com o paraquat. A partir das análises espectroscópicas (FTIR) e estruturais (DRX), foi possível determinar a incorporação das nanoestruturas nos hidrogéis bem como os fármacos e herbicida estudados. Além disso, as análises térmicas demonstraram que a presença de nanoestruturas diminui a taxa de massa perdida pelos hidrogéis. A eficiência de encapsulação dos hidrogéis atingiram valores acima de 70% e os estudos de liberação controlada demonstraram que hidrogéis compósitos reticulados com Ca2+ liberaram o fármaco por até 32 h. Para a liberação do herbicida, destaca-se que os hidrogéis nanocompósitos contendo zeólita apresentaram liberação sustentada à medida que a concentração da mesma foi aumentada, já nos hidrogéis contendo nanoargila não houve liberação do herbicida. A partir de todos os resultados apresentados, os autores concluem que os hidrogéis desenvolvidos neste trabalho possuem potencial para serem aplicados como sistemas de liberação controlada no tocante a administração de fármacos ou defensivos agrícolas.
The problem referring to the implications arising from of recurrent applications of drugs and/or agricultural defensives in high concentrations on living beings and the environment motivated the authors to develop bionanocomposite hydrogels based on polymer systems capable of minimizing the impasses regarding contamination and collateral effects from a controlled release of the proposed drugs and herbicide. Thus, the hydrogels were prepared from natural polysaccharides and inorganic nanostructures in which it was crosslinked with different ions (Mn2+, Zn2+ or Ca2+). The hydrogels were characterized according to their hydrophilic, structural, spectroscopic, morphological, thermal, sorption and desorption properties of drugs or herbicide. Regarding the swelling degree and adsorption of the herbicide, the Mn2+ crosslinked hydrogels presented the highest values, because this ion has the smaller ionic radius about Zn2+ and Ca2+. On the other hand, the addition of nanostructures (clay or zeolite) decreased the swelling degree of the hydrogels, because theses increased the crosslinking density, this effect was confirmed by SEM analysis. In contrast, the presence of nanostructures has increased the amount of herbicide paraquat adsorbed, due to the presence of polar groups that make it possible and interaction with paraquat. From the spectroscopic (FTIR) and structural (DRX) analyses, it was possible to determine the incorporation of nanostructures in the hydrogels as well as the drugs and herbicide studied. In addition, thermal analyses showed that the presence of nanostructures decreases the rate of mass loss by the hydrogels. The encapsulation efficiency of the hydrogels reached values above 70% and the controlled release studies showed that Ca2+ crosslinked composite hydrogels released the drug for up to 32 h. For the release of the herbicide, it is highlighted that the nanocomposite hydrogels containing zeolite showed sustained release as its concentration was increased, whereas that in the hydrogels containing nanoclay there was no release of the herbicide. From all the results presented, the authors conclude that the hydrogels developed in this work have the potential to be applied as controlled release systems regarding the administration of drugs or agricultural defensives.
The problem referring to the implications arising from of recurrent applications of drugs and/or agricultural defensives in high concentrations on living beings and the environment motivated the authors to develop bionanocomposite hydrogels based on polymer systems capable of minimizing the impasses regarding contamination and collateral effects from a controlled release of the proposed drugs and herbicide. Thus, the hydrogels were prepared from natural polysaccharides and inorganic nanostructures in which it was crosslinked with different ions (Mn2+, Zn2+ or Ca2+). The hydrogels were characterized according to their hydrophilic, structural, spectroscopic, morphological, thermal, sorption and desorption properties of drugs or herbicide. Regarding the swelling degree and adsorption of the herbicide, the Mn2+ crosslinked hydrogels presented the highest values, because this ion has the smaller ionic radius about Zn2+ and Ca2+. On the other hand, the addition of nanostructures (clay or zeolite) decreased the swelling degree of the hydrogels, because theses increased the crosslinking density, this effect was confirmed by SEM analysis. In contrast, the presence of nanostructures has increased the amount of herbicide paraquat adsorbed, due to the presence of polar groups that make it possible and interaction with paraquat. From the spectroscopic (FTIR) and structural (DRX) analyses, it was possible to determine the incorporation of nanostructures in the hydrogels as well as the drugs and herbicide studied. In addition, thermal analyses showed that the presence of nanostructures decreases the rate of mass loss by the hydrogels. The encapsulation efficiency of the hydrogels reached values above 70% and the controlled release studies showed that Ca2+ crosslinked composite hydrogels released the drug for up to 32 h. For the release of the herbicide, it is highlighted that the nanocomposite hydrogels containing zeolite showed sustained release as its concentration was increased, whereas that in the hydrogels containing nanoclay there was no release of the herbicide. From all the results presented, the authors conclude that the hydrogels developed in this work have the potential to be applied as controlled release systems regarding the administration of drugs or agricultural defensives.
Descrição
Palavras-chave
Hidrogéis, Liberação controlada, Paraquat, Paracetamol, Diclofenaco de sódio, Hydrogels, Controlled release, Sodium diclofenac