Preparation of Abamectin Nanoparticles by Flash NanoPrecipitation for Extended Photostability and Sustained Pesticide Release

Abamectin has been widely used as a biopesticide to control pests, such as pinewood and root-knot nematodes. However, the low aqueous solubility and poor photostability of abamectin have largely hindered the delivery and bioavailability of conventional formulations, causing a significant rise in costs as well as limiting the large-scale application in crop production. Here, we report the formulation of abamectin nanopesticides for extended photostability and sustained release, using a continuous and scalable technique called Flash NanoPrecipitation (FNP). Cost-effective and biocompatible stabilizers, hypromellose acetate succinate (HPMCAS) and lecithin, were used in the formulation with optimized mass ratios for nanoparticle stability. The encapsulation efficiency of abamectin in nanoparticles was higher than 90% with a mass loading capacity up to 50%. The optimized formulations not only showed improved photostability compared with free abamectin but also achieved more sustained release behaviors in a controlled manner. These results suggest that the abamectin nanoparticles formulated by FNP can improve the performance of the aqueous solubility, photostability, and controlled release of abamectin. In addition, our work highlights the potential of FNP for the mass production of low-cost abamectin nanopesticides with affordable materials, which is essential for the large-scale application of nanopesticides in food and agriculture.