Glucose-based nano-solid dispersion system of pyraclostrobin with excellent dispersibility and fungicidal activity

In modern agriculture, pesticides are indispensable for securing crop yields and managing pests and diseases. However, a large proportion of currently used active ingredients exhibit poor water solubility, which compromises their dispersion, bioavailability, and overall field efficacy. This inherent limitation inevitably leads to excessive application rates, escalating environmental contamination and posing risks to non-target organisms. Nanotechnology offers a promising strategy to address these challenges by reducing particle sizes to the nanoscale, thereby improving dissolution kinetics, foliar wettability, and target deposition.

In this study, the pyraclostrobin nano-solid dispersion (Pyr-NSD) was fabricated with glucose as the carrier and emulsifier 600 as the surfactant. The Pyr-NSD exhibited a hydrodynamic mean diameter of 42 nm and an excellent suspension rate of 99.2%. Scanning electron microscopy (SEM) revealed uniformly distributed spherical nanoparticles with an average size of approximately 40 nm. Based on the contact angle and surface tension measurements on cucumber and cabbage leaves, the Pyr-NSD demonstrated superior dispersibility, wetting, and spreading properties compared with the commercial water-dispersible granules (WDGs). Moreover, Pyr-NSD demonstrated superior biosafety, maintaining cell viability above 90% in in vitro cytotoxicity assays on HepG2 cells and achieving a 100% seed germination rate on cucumber seeds in phytotoxicity tests. The fungicidal activity of the formulation was further evaluated using Botrytis cinerea as a model fungus. The median effective concentration (EC₅₀) of Pyr-NSD was determined to be 0.721 mg L^-1, representing a potency 1.95 times that of the WDGs, accompanied by a significant reduction in intracellular enzyme activity within the mycelia.

This study establishes that the glucose-based Pyr-NSD formulation substantially improves the dispersibility, wettability, and antifungal potency of pyraclostrobin while exhibiting favorable biosafety profiles. The 1.95-fold increase in fungicidal efficacy, coupled with reduced surfactant demand and excellent storage stability, underscores the practical viability of this nano-solid dispersion strategy for reducing pesticide input and environmental footprint. These findings provide a robust and scalable platform for upgrading poorly soluble pesticides, advancing the development of next-generation agrochemical formulations with superior performance and ecological compatibility. © 2026 Society of Chemical Industry.