Development of abamectin-loaded nanoemulsion and its insecticidal activity and cytotoxicity

Owing to the advantages of high-efficiency, environmental protection and safety, nanoemulsions have become a highly popular water-insoluble pesticide delivery system in recent years.

In this study, abamectin-loaded nanoemulsion with remarkable physical stability and application performance was obtained by selecting the type and concentration of surfactant and the emulsification method. The optimal formula was 2% abamectin and 5% castor oil polyoxyethylene (EL-40) dissolved in 7.5% hydrocarbon solvent (S-200) made up to 100% with deionized water, which conformed to the quality indicators from the Food and Agriculture Organization (FAO) standards. Droplets on cabbage leaves showed a small dynamic contact angle, which ensured that the resulting nanoemulsion exhibited excellent wettability and diffusivity. Compared with emulsifiable concentrates (EC) and microemulsions (ME), the abamectin-loaded nanoemulsion had the lowest LC₅₀ (0.0686 mg L^-1 ) to third-instar larva of Plutella xylostella, causing the larval body to blacken and shrivel, which improved insecticidal activity. In addition, the abamectin-loaded nanoemulsion had low cytotoxicity. The viability of dendritic cells with added nanoemulsion reached 100% after 2 h, whereas that of cells with EC and ME was lower. After 24 h, the cell viability of dendritic cells with added ME was 0.

This research facilitated the design and fabrication of nanoemulsions for water-insoluble pesticide to enhance insecticidal activity, lower cytotoxicity and reduce environmental pollution. © 2020 Society of Chemical Industry.