A hydroxypropyl methyl cellulose-based nano-pesticide delivery system for enhanced photostability and insecticidal activity of indoxacarb

Abstract

The utilization of nano-pesticides offers a more sustainable approach to agricultural development, as they exhibit reduced environmental pollution and enhanced bioavailability compared to conventional pesticides. In this study, hydroxypropyl methyl cellulose (HPMC) was employed as the carrier for indoxacarb pesticide, through the implementation of high-speed stirring cutting and ultrasonic dispersion technology, and an indoxacarb-hydroxypropyl methyl cellulose (IN@HPMC) nano-formulation with a particle size of approximately 200 nm was successfully prepared. The IN@HPMC nano-formulation exhibits excellent sustained-release ability. Compared with commercial indoxacarb suspension (IN-SC), IN-SC was completely released at 81 h after release at 25°C under 30% acetonitrile solution. The release rate of IN@HPMC nano-formulation was 71%. Moreover, it demonstrates a photolytic half-life (T_0.5) of 117 h, indicating significantly enhanced resistance to photolysis compared to general indoxacarb suspension (IN-SC, T_0.5: 2.8h). Additionally, compared to the IN-SC control group, the IN@HPMC nano-formulation shows significantly enhanced insecticidal toxicity and duration, and the fatality rate in the IN@HPMC group reached 72% at a concentration of 12.5 ppm, whereas the IN-SC group is only 39%. Furthermore, it has lower plant toxicity than indoxacarb while being non-toxic to normal human cells.