Oil-in-water nanoemulsions for pesticide formulations

A two-step process for formation of nanoemulsions in the system water/poly(oxyethylene) nonionic surfactant/methyl decanoate at 25 °C is described. First, all the components were mixed at a certain composition to prepare a microemulsion concentrate, which was rapidly subjected into a large dilution into water to generate an emulsion. Bluish transparent oil-in-water (O/W) nanoemulsions were formed only when the concentrate was located in the bicontinuous microemulsion (BC) or oil-in-water microemulsion (Wm) region. The existence of an optimum oil-to-surfactant ratio (RosRos) in the BC or Wm region indicates that both the phase behavior and the composition of the concentrate are important factors in nanoemulsion formation. To demonstrate potential applications of these systems, they were employed to formulate a water-insoluble pesticide, β-cypermethrin (β-CP). The nanoemulsion was compared with a commercial β-CP microemulsion in terms of the stability of sprayed formulations.

A two-step process for formation of nanoemulsions in the system water/poly(oxyethylene) nonionic surfactant/methyl decanoate at 25 °C is described. The droplet sizes of the resulting nanoemulsions were strongly affected by the final water concentration after dilution of the initial concentrate. Bluish transparent oil-in-water (O/W) nanoemulsions were formed only when the concentrate was located in the bicontinuous microemulsion (BC) or oil-in-water microemulsion (Wm) region.Figure optionsDownload as PowerPoint slide