Abstract
This work proposed synthesis of chitosan NPs and silica NPs, conjugation of deltamethrin with chitosan NPs and silica NPs to produce chitosan loaded with deltamethrin and silica loaded with deltamethrin to be used against disease vectors, such as mosquito, and assessment of the acute toxicity in male albino rats. First, dynamic light scattering technique verified the hydrodynamic size of chitosan loaded with deltamethrin and silica loaded with deltamethrin (568.3 +/- 15.36 and 284.6 +/- 11.23 nm, respectively) and the negative zeta potential value (- 12.5 and - 20.8 mV, respectively). Deltamethrin encapsulation efficiency was found to be 87.031% in chitosan loaded with deltamethrin and 93.739% in silica loaded with deltamethrin. Second, chitosan loaded with deltamethrin and silica loaded with deltamethrin were exposed to mosquito (Culex pipiens larvae) for a 24-h bioassay, and the results were compared with the bulk deltamethrin. The LC50 of chitosan loaded with deltamethrin, silica loaded with deltamethrin, and deltamethrin was found to be 0.5718, 0.0186, and 0.3388 mg/L, respectively. Third, the median lethal dose of deltamethrin, chitosan loaded with deltamethrin, and silica loaded with deltamethrin was calculated using Dixon's up-and-down method (38.55, 304.438, and 87.95 mg/kg, respectively). The acute toxicity was evaluated at 14 d after oral administration of deltamethrin at 25.35, 32.95 and 42.84 mg/kg, chitosan loaded with deltamethrin at 217.20, 282.36 and 367.06 mg/kg and silica loaded with deltamethrin at 57.8, 75.13 and 97.68 mg/kg. It was concluded that silica loaded with deltamethrin and chitosan loaded with deltamethrin can be used as an effectual larvicide at low concentrations and a safe alternative to deltamethrin with minimal environmental impacts.