Synthesis and preliminary evaluation of carbendazim nanoemulsions as larvicidal agent against Culex mosquitoes

The larvicidal potential of carbendazim nanoemulsion was studied against the 4^th instar Culex larvae. The nanoemulsion was prepared by spontaneous emulsification technique using oleic acid, tween 20 and acetone as oil, surfactant and cosurfactant, respectively, after optimization. Stable nanoemulsions were formed with spherical droplets of size 80–140 nm. They were characterized for transparency, drug content, compatibility, pH, viscosity, stability and size. The larvicidal activity was assessed upto 24h against Culex with varying concentrations by following the WHO (2005) methods. The LC₅₀ value (median lethal concentration) was calculated. Carbendazim dosage from 2000 ppm to 4 ppm recorded 100% mortality and the calculated LC50 value was 1.631 ppm. Carbendazim nanoemulsions can be considered as a better alternative due to lower toxicity and easy degradability in comparison to standard organophosphorus and organochlorines