Department of Environmental Engineering, UNESP-Univ. Estadual Paulista, Avenida Três de Março, no. 511, 18087-180 Sorocaba, SP, Brazil.
J Hazard Mater. 2012 Sep 15;231-232:1-9. doi: 10.1016/j.jhazmat.2012.06.019. Epub 2012 Jun 29.
The toxicity of herbicides used in agriculture is influenced by their chemical stability, solubility, bioavailability, photodecomposition, and soil sorption. Possible solutions designed to minimize toxicity include the development of carrier systems able to modify the properties of the compounds and allow their controlled release. Polymeric poly(ε-caprolactone) (PCL) nanocapsules containing three triazine herbicides (ametryn, atrazine, and simazine) were prepared and characterized in order to assess their suitability as controlled release systems that could reduce environmental impacts. The association efficiencies of the herbicides in the nanocapsules were better than 84%. Assessment of stability (considering particle diameter, zeta potential, polydispersity, and pH) was conducted over a period of 270 days, and the particles were found to be stable in solution. In vitro release kinetics experiments revealed controlled release of the herbicides from the nanocapsules, governed mainly by relaxation of the polymer chains. Microscopy analyses showed that the nanocapsules were spherical, dense, and without aggregates. In the infrared spectra of the PCL nanocapsules containing herbicides, there were no bands related to the herbicides, indicating that interactions between the compounds had occurred. Genotoxicity tests showed that formulations of nanocapsules containing the herbicides were less toxic than the free herbicides. The results indicate that the use of PCL nanocapsules is a promising technique that could improve the behavior of herbicides in environmental systems.
农业中使用的除草剂的毒性受其化学稳定性、溶解度、生物利用度、光解和土壤吸附的影响。旨在最大限度降低毒性的可能解决方案包括开发能够改变化合物性质并允许其控制释放的载体系统。制备并表征了含有三种三嗪类除草剂（莠去津、阿特拉津和西玛津）的聚（ε-己内酯）（PCL）纳米胶囊，以评估其作为控制释放系统的适用性，该系统可降低对环境的影响。除草剂在纳米胶囊中的结合效率优于 84%。在 270 天的时间内对稳定性（考虑粒径、zeta 电位、多分散性和 pH）进行了评估，结果表明纳米胶囊在溶液中稳定。体外释放动力学实验表明，除草剂从纳米胶囊中得到控制释放，主要受聚合物链松弛的控制。显微镜分析表明纳米胶囊呈球形、致密且无聚集体。在含有除草剂的 PCL 纳米胶囊的红外光谱中，没有与除草剂相关的带，表明化合物之间发生了相互作用。遗传毒性试验表明，含有除草剂的纳米胶囊制剂的毒性小于游离除草剂。结果表明，使用 PCL 纳米胶囊是一种很有前途的技术，可以改善除草剂在环境系统中的行为。
