Poly(hydroxybutyrate-co-hydroxyvalerate) microspheres loaded with atrazine herbicide: screening of conditions for preparation, physico-chemical characterization, and in vitro release studies
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Data
2011-07-01
Autores
Lobo, Fabiana Aparecida
de Aguirre, Carina Levy [UNESP]
Silva, Mariana Santos [UNESP]
Grillo, Renato [UNESP]
Silva de Melo, Nathalie Ferreira [UNESP]
de Oliveira, Liliam Karla [UNESP]
de Morais, Leandro Cardoso [UNESP]
Campos, Valquiria [UNESP]
Rosa, Andre Henrique [UNESP]
Fraceto, Leonardo Fernandes [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Springer
Resumo
Due to their widespread use in agriculture as well as in urban areas, agricultural chemicals are globally some of the most commonly encountered substances in waters. The objective of this study is to develop (including preparation and characterization) a new modified release system for the herbicide atrazine, employing poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) microspheres. The microspheres were prepared by the emulsification/solvent evaporation method, emulsifying an organic phase (atrazine and PHBV dissolved in chloroform) into an aqueous phase containing polyvinyl alcohol (PVA) as surfactant, under stirring, and then evaporating the solvent. A 2(4-1) fractional factorial design, investigating the influence of four variables at two levels, was performed to obtain formulations with optimized association efficiencies. There was a greater dependence of association efficiency on PVA concentration (negative) and the mass of polymer (positive) with lesser influence of both stirring speed and organic phase volume. The size of the particles was assessed using scanning electron microscopy, which showed that the particles were rough-surfaced spheres. The results obtained are promising, since the formulations presented encapsulation efficiency near 25% and the release kinetics profile of atrazine was altered when it was encapsulated in the microparticles, indicating that these systems may be efficient in reducing the environmental impact caused by the herbicide, hence making it safer to use.
Descrição
Palavras-chave
Microparticles, Atrazine, PHBV, Controlled release, Emulsification-Solvent evaporation, Microencapsulation
Como citar
Polymer Bulletin. New York: Springer, v. 67, n. 3, p. 479-495, 2011.