Study on the inclusion complexes of Flumorph and Dimethomorph with β-Cyclodextrin to improve fungicide formulation

The β-cyclodextrin (β-cd) complexes of flumorph and dimethomorph have been investigated quantitatively by uv measurement. the results showed that the 1:1 inclusion complexes were formed and the formation constants reduced with elevation of temperature. thermodynamic parameters of the inclusion reaction (δh,δs,δg) were all negative,which suggested that the interaction process between β-cd and the two fungicides were spontaneous,driven by entropy changes of inclusion reaction. two-dimensional (2d) roesy nmr experiments were performed to identify the binding geometry of inclusion complex. both of z and e isomers of flumorph formed complexes with β-cd,while only the z-isomer of dimethomorph formed complex with β-cd,and the phenyl ring containing fluorine or chlorine atom entered into the cavity of β-cd through the wider rim. phase-solubility experiments demonstrated that the water-solubility of the two fungicides enhanced in the presence of β-cd. the preliminary bioassay testified that the complexes improved the fungicidal activity. the present study provided a promising outlook for developing water-based formulation of flumorph and dimethomorph,increasing its efficacy and improving its formulation.