Enhanced solubilization of an insect juvenile hormone (JH) mimetic (piryproxyfen) using eugenol in water nanoemulsions stabilized by a triblock copolymer of poly(ethylenglycol) and poly(propilenglycol)

The encapsulation of a synthetic insecticide, pyriproxyfen, has been carried out using eugenol in water nanoemulsions, including different weight fractions of oil phase (eugenol), and stabilized by a triblock amphiphilic copolymer, poloxamer 407. Dynamic Light Scattering (DLS) experiments have evidenced the formation of polydisperse nanoemulsions, in both nanoemulsions free of the insecticide and those containing it. These nanoemulsion present a good long-term stability, and only a slight sedimentation of the bigger droplets was found after several months of storage (the aging during 24 months of the nanoemulsions was evaluated). This long-term chemical and physical stability is important for the potential application of these systems in insect pest control, which may also take advantage of the high solubilization efficiency of piryproxyfen evidenced by the nanoemulsions. Therefore, this study combined with an additional evaluation of the efficiency of these formulations, may open many possibilities for the preparation of ready-to-use formulations against different insect pests.