title: Encapsulation and controlled release of hydrophilic pesticide in shell cross-linked nanocapsules containing aqueous core.
abstract: In this study, amphiphilic biocopolymers, synthesized by mixing azidobenzaldehyde (Az) and an aqueous solution of carboxymethyl chitosan (CMCS), which self-assemble into nanocapsules with a aqueous core (ACN) in aqueous media followed by photo-cross-linking to obtain shell cross-linked nanocapsules, were used to develop a controlled release pesticide system. The system was characterized by TEM and DLS. Its encapsulation efficiency was determined. The obtained result showed that it is efficient to encapsulate methomyl reaching encapsulation efficiency as high as 90% in an aqueous medium at pH 4.0, which is mainly attributed to the hydrogen bonding adsorption between methomyl molecules and the inner surface of nanocapsules. Release profiles of methomyl from methomyl-loaded nanocapsules in an aqueous solution at pH 6.0 were shown to be diffusion controlled with a half-release time (t(½)) of 36.3-69.5h from different samples. The shell cross-linking and its degree of cross-linking are assumed to be responsible for this diffusion behavior. The insecticidal activity test in laboratory showed that the control efficacy of methomyl-loaded nanocapsules against the armyworm larvae was significantly superior to the original. The relative control efficacy still maintained 100% over 7 days.
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Chuxiang
authors.initials: C
authors.lastname: Sun
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Ke
authors.initials: K
authors.lastname: Shu
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Ye
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China. Electronic address: yihuayin@aliyun.com.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zheng
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Guanghua
authors.initials: G
authors.lastname: He
authors.affiliation: Department of Pharmaceutical Engineering, School of Chemical Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Yin
mesh_terms: D000818:Animals; D001386:Azides / Q000737:chemistry; D001547:Benzaldehydes / Q000737:chemistry; D048271:Chitosan / Q000031:analogs & derivatives / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry; D004339:Drug Compounding; D057927:Hydrophobic and Hydrophilic Interactions; D007814:Larva / Q000187:drug effects; D008724:Methomyl / Q000737:chemistry* / Q000633:toxicity; D053769:Nanocapsules / Q000737:chemistry* / Q000633:toxicity; D010575:Pesticides / Q000737:chemistry* / Q000633:toxicity; D018411:Spodoptera
chemical_list: D001386:Azides; D001547:Benzaldehydes; D003692:Delayed-Action Preparations; D053769:Nanocapsules; D010575:Pesticides; C514968:carboxymethyl-chitosan; D008724:Methomyl; C026479:4-azidobenzaldehyde; D048271:Chitosan
keywords: Controlled release; Encapsulation; Nanocapsule; Pesticide; Shell cross-linked