Formulation and evaluation of norcanthridin nanoemulsions against the Plutella xylostella (Lepidotera: Plutellidae).

ABSTRACT:

Background

Norcantharidin (NCTD), a demethylated derivative of cantharidin (defensive toxin of blister beetles), has been reported to exhibit insecticidal activity against various types of agricultural pests. However, NCTD applications are limited by its poor water solubility and high dosage requirement. Nanoemulsions have attracted much attentions due to the transparent or translucence appearance, physical stability, high bioavailability and non-irritant in nature. In general, nanoemulsions with small droplet size can enhance the bioavailability of drugs, whereas this phenomenon is likely system dependent. In present study, NCTD nanoemulsions were developed and optimized to evaluate and improve the insecticidal activity of NCTD against Plutella xylostella (Lepidotera: Plutellidae) by a spontaneous emulsification method.

Results

Triacetin, Cremophor EL and butanol were selected as the constituents of NCTD nanoemulsions via solubility determination, emulsification efficiency and ternary phase diagram construction. Insecticidal activity of NCTD nanoemulsion was associated with the content of surfactant and cosurfactant: (1) Higher effective toxicity exhibited at Smix (surfactant to cosurfactant mass ratio)?=?3:1 that may be associated with the changes in interfacial tension; (2) NCTD nanoemulsion at 3:7?ConclusionsThe optimized NCTD nanoemulsion (triacetin/Cremophor EL/butanol (60/20/20, w/w)) exhibited effective insecticidal activity (LC₅₀ 60.414?mg/l, LC₉₀ 185.530?mg/l, 48?h) than the NCTD acetone solution (LC₅₀ 175.602?mg/L, LC₉₀ 303.050?mg/L, 48?h). Spontaneous emulsifying nanoemulsion employed to formulate this poor water-soluble pesticide is a potential system for agriculture application.

SUBMITTER: Zeng L 

PROVIDER: S-EPMC6419361 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature