Inclusion of quinestrol and 2,6-di-O-methyl-β-cyclodextrin: Preparation, characterization, and inclusion mode

An inclusion complex between chemosterilant quinestrol and 2,6-di-O-methyl-β-cyclodextrin (DM-β-CD) was prepared using the solution-ultrasonic method. A 1:1 stoichiometry was confirmed by elemental analysis. Analytical techniques such as UV–vis spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were used to characterize the complex. Proton NMR and nuclear Overhauser effect spectroscopy results indicate that the hydroxyl end and alkynyl end of quinestrol was included in the DM-β-CD cavity, which agrees with the most predominant configuration optimized by molecular modeling. The water solubility of quinestrol was significantly increased through complexation with DM-β-CD. The DM-β-CD complexes can be used in the design of a novel formulation of quinestrol for rat control products in agriculture.