Poly(hydroxybutyrate-co-hydroxyvalerate) microspheres loaded with atrazine herbicide : screening of conditions for preparation, physico-chemical characterization, and in vitro release studies.
Nenhuma Miniatura disponível
Data
2011
Título da Revista
ISSN da Revista
Título de Volume
Editor
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 24-1 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
Citação
LOBO, F. A. et al. Poly(hydroxybutyrate-co-hydroxyvalerate) microspheres loaded with atrazine herbicide: screening of conditions for preparation, physico-chemical characterization, and in vitro release studies. Polymer Bulletin, Berlin, v. 67, p. 479-495, 2011. Disponível em: <https://link.springer.com/article/10.1007/s00289-011-0447-6>. Acesso em: 20 abr. 2017.