Min Li1, Qiliang Huang, Yan Wu. 1. Key Laboratory of Pesticide Chemistry and Application, MOA, Institute of Plant Protection, CAAS, Beijing, China.
Abstract
BACKGROUND: The aim of the present work was to synthesise novel amphiphilic chitosan-co-(D,L-lactide) (chitosan-PLA) copolymers and to study the formation of pesticide-loaded polymeric submicron particles. These copolymeric submicron particle systems are expected to be potential candidates for applications in pesticide delivery. RESULTS: The chemical structures of the copolymers were confirmed by Fourier transform infrared spectroscopy (FT-IR), (1) H nuclear magnetic resonance ((1) H NMR) and thermogravimetric analysis (TGA). Imidacloprid as a lipophilic model pesticide can be incorporated into chitosan-PLA submicron particles by nanoprecipitation and the emulsion/solvent evaporation method. Size, the size distribution, the imidacloprid loading content (LC) and the imidacloprid release behaviour were investigated. CONCLUSION: Conjugation of PLA to chitosan was shown to be an available method for the preparation of submicron particles for lipophilic pesticide delivery. The imidacloprid-loaded submicron particles showed a sustained release process. As the mass ratio of copolymer to imidacloprid increased, the submicron particles size and LC decreased. The chitosan-PLA submicron particles could be useful as pesticide carriers for imidacloprid delivery systems.
BACKGROUND: The aim of the present work was to synthesise novel amphiphilic chitosan-co-(D,L-lactide) (chitosan-PLA) copolymers and to study the formation of pesticide-loaded polymeric submicron particles. These copolymeric submicron particle systems are expected to be potential candidates for applications in pesticide delivery. RESULTS: The chemical structures of the copolymers were confirmed by Fourier transform infrared spectroscopy (FT-IR), (1) H nuclear magnetic resonance ((1) H NMR) and thermogravimetric analysis (TGA). Imidacloprid as a lipophilic model pesticide can be incorporated into chitosan-PLA submicron particles by nanoprecipitation and the emulsion/solvent evaporation method. Size, the size distribution, the imidacloprid loading content (LC) and the imidacloprid release behaviour were investigated. CONCLUSION: Conjugation of PLA to chitosan was shown to be an available method for the preparation of submicron particles for lipophilic pesticide delivery. The imidacloprid-loaded submicron particles showed a sustained release process. As the mass ratio of copolymer to imidacloprid increased, the submicron particles size and LC decreased. The chitosan-PLA submicron particles could be useful as pesticide carriers for imidacloprid delivery systems.