Abstract
The effects of formulation variables on the formation of beta-cypermethrin nanosuspension prepared from the dilution of microemulsion have been investigated systematically. The formation of nanosuspension depends on several parameters. Surfactants and co-surfactants are the crucial parameters determine the formation of nanosuspension. The size of nanoparticles could be influenced by the species of surfactants (nonionic surfactant, ionic surfactant, high molecular weight surfactant), and the combination of stabilizers might provide additional long-term stabilization. The size and ripening rate of nanosuspension decrease with the increase of polarity of solvent. When the concentration of beta-cypermethrin in oil over 37.5 wt%, microparticles formation process was monitored. Furthermore, the electrolyte in diluted media showed little influence on size when dilution-fold over 40.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (NSFC 20233010 and 20573079).
Notes
*Butanol was used as co-surfactant.
*For comparison, other compounds kept the same on weight except for ME (CBC = 37.5 wt%) more butanol was used to form microemulsion.