Preparation and Characterization of Butachlor/(2-Hydroxypropyl)-β-cyclodextrin Inclusion Complex: Improve Soil Mobility and Herbicidal Activity and Decrease Fish Toxicity

A water-soluble inclusion complex for butachlor was prepared by complexation with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD). Phase solubility results indicated a 1:1 stoichiometric ratio with an apparent stability constant of 864.3 M –1 in the obtained solid complex. The formation of the complex was confirmed by 1 H nuclear magnetic resonance, Fourier transform infrared, and differential scanning calorimetry spectra. Coupled with the molecular docking results, butachlor was considered to be completely included in HP-β-CD cavity. Butachlor complexation with HP-β-CD decreased its adsorption capacity and enhanced its mobility in soil. The inclusion complex displayed better herbicidal activities than free butachlor. The 96 h median lethal concentration values of the inclusion complex and free butachlor was 2.30 and 0.65 mg L –1, respectively, for zebrafish, indicating that the complexation could significantly reduce toxicity to fishes. The present study provides an approach to develop environment-friendly formulations using CDs for herbicides.