Synthesis, Characterization and Toxicity Assessment of Chlorantraniliprole Nanosuspension and Its Environmental Risk

Abstract

Chlorantraniliprole is an anthranilic diamide-class insecticide that functions as a ryanodine receptor agonist. It is recognized for its high efficacy, low mammalian toxicity, prolonged persistence, and minimal residual presence. This study developed a stable Oil-in-Water (O/W) nanosuspension of chlorantraniliprole using a combination of a solvent and the non-ionic surfactant Tween-80. A high-energy emulsification process, namely ultrasonication, was employed to achieve a nanometer-scale particle size. The successful formation of the chlorantraniliprole nanosuspension was verified using dynamic light scattering and transmission electron microscopy. Its stability was assessed through tests for viscosity, centrifugation, and resilience to heating-cooling and freeze-thaw cycles. The environmental safety of both the conventional Chlorantraniliprole (CAP) and Chlorantraniliprole Nanosuspension (CAPN) insecticides was evaluated using earthworms (Lumbricus terrestris) and honeybees (Apis mellifera Linnaeus) as model organisms. Earthworms were subjected to concentrations ranging from 3.75 to 60.0 mg/L for 30 days. Concurrently, the fate and transport of CAP within the soil-earthworm system were monitored. After the 30-day exposure, treatment with 60.0 mg/kg of CAP and CAPN resulted in earthworm mortality not exceeding 20%. Furthermore, a significant reduction in earthworm body weight to 7.59 and 8.09 gm was recorded following application of CAP and CAPN, respectively. In a parallel bioassay, honeybees were exposed to the same range of concentrations (3.75-60.0 mg/L), with mortality evaluated at 12, 24, 36, and 48-hour intervals. Mortality of honeybees reached 100% after application of CAP and CAPN for 48 h. Based on recent studies on CAPN, which highlight its enhanced solubility, stability, and bioefficacy compared to conventional formulations of CAP, there is a clear need for expanded field application research to measure its real-world efficiency, especially since laboratory trials have shown promising results.