Design of Multifunctional SC-PLA Pesticide Carrier System and Study of Controlled-Release Performance

To construct a high-performance avermectin (Avm) carrier system, this study utilized the advantages of stereocomplex (SC) crystal formation between poly (L-lactic acid) (PLLA) and poly (D-lactic acid) (PDLA) to prepare Avm-loaded stereocomplex polylactic acid (SC-PLA) nanoformulations via the emulsion solvent evaporation method. The results showed the successful formation of SC-PLA after introducing PDLA into the PLLA matrix, and the influence of SC-PLA crystallinity enabled the fabrication of tunable Avm@SC-PLA nanospheres with a regular spherical morphology. Avm@SC-PLA exhibited controlled release characteristics and possessed pH-responsive properties with specific release behaviors under pH 5.5, 7.4, and 8.0 conditions. The Avm@SC-PLA sustained-release nano system had a series of advantages, including controllable particle size, efficient drug loading, excellent sustained-release performance, good UV-shielding ability, high stability, favorable spreadability, and strong affinity for different leaves. In conclusion, the Avm@SC-PLA nanoformulation not only achieves effective loading and stable encapsulation of Avm but also possesses good structural stability and environmental responsiveness. It provides a novel PLA-based carrier strategy for the efficient delivery of Avm and holds potential application value in the pesticide and pharmaceutical fields.