Size-Dependent Effect of Prochloraz-Loaded mPEG-PLGA Micro- and Nanoparticles

As a controlled release formulation, polymer-based pesticide particle, provide an effective approach to achieve the target crop sites of increasing the pesticide utilization and reducing side effects. The particle size impacts on the dispersibility, pesticide loading content, control effect, etc. It is essential to investigate size-dependent effect. Hence, size-dependent effect of polymer-based pesticide particle was studied systematically in this paper. The biodegradable mPEG-PLGA copolymer with suitable molecular weight (45 KDa) was selected as carrier. Prochloraz-loaded mPEG-PLGA particles with different sizes (190.7 nm, 708.8 nm and 3980.0 nm) were constructed by emulsion/solvent evaporation method based on the same carrier. With the constant mass ratio of copolymer/prochloraz, as the particle size became large, the prochloraz loading content increased, and prochloraz released speed decreased. All prochloraz-loaded particles showed a sustained-release process and sustained impact against the Fusarium graminearum. Among the prochloraz-loaded mPEG-PLGA particles, the 190.7 nm particles exhibited the best germicidal efficacy in two weeks. Hence, the smaller size particles hold a better control efficacy in short time.