A novel chitosan-poly(lactide) copolymer and its submicron particles as imidacloprid carriers

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), ¹H nuclear magnetic resonance (¹H 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. Copyright © 2011 Society of Chemical Industry