Coprecipitation-based synchronous chlorantraniliprole encapsulation with chitosan: carrier-pesticide interactions and release behavior

BACKGROUNDControlled-release pesticide formulations have emerged as a promising approach towards sustainable pest control. Herein, an environment-friendly formulation of insecticide chlorantraniliprole (CAP) was fabricated through a simple approach of coprecipitation-based synchronous encapsulation by chitosan (CTS), with carrier-pesticide interaction mechanism and release behavior investigated. RESULTSThe resulting CAP/CTS controlled-release formulation (CCF) showed a good loading content of 28.1% and a high encapsulation efficiency of 75.6%. Instrument determination in combination with molecular dynamics (MD) simulations displayed that the primary interactions between CAP and CTS were physical adsorption and complicated hydrogen (H)-bonds, which formed dominantly between N-H in amides [or nitrogen (N) in ring structures] of CAP and hydroxyl (or amino) groups of CTS, as well as oxygen (O) in CAP with hydrogen in CTS or H2O molecules. The in vitro release tests exhibited obvious pH/temperature sensitivity, with release dynamics following the first-order or Ritger-Peppas model. As the temperature increased, the CAP release process of the Ritger-Peppas model changed from Case-II to anomalous transport, and ultimately to a Fickian diffusion mechanism. The control effect against Plutella xylostella larvae also was evaluated by toxicity tests, where comparable efficacy of CCF to the commercial suspension concentrate was obtained. CONCLUSIONThe innovative, easy-to-prepare CCF can be used as a formulation with obvious pH/temperature sensitivity and good efficacy on target pests. This work contributes to the development of efficient and safe pesticide delivery systems, especially using the natural polymer materials as carriers. (c) 2023 Society of Chemical Industry.

Automated summary

In this study, an environment-friendly controlled-release formulation of chlorantraniliprole (CAP) was successfully prepared using chitosan through coprecipitation. The CAP/CTS controlled-release formulation exhibited high loading content, encapsulation efficiency, and pH/temperature sensitivity. Toxicity tests confirmed the comparable efficacy of CCF to the commercial suspension concentrate.