Bioavailability and nervous tissue distribution of pyrethroid insecticide cyfluthrin in rats

Toxicokinetics of cyfluthrin after single oral [20 mg/kg body weight (bw)] and intravenous (IV) (3 mg/kg bw) doses were studied in rats. Serial blood samples were obtained after oral and IV administration. Brain tissue samples were also collected after oral administration. Cyfluthrin concentrations in plasma and brain tissues (hypothalamus, striatum, hippocampus and frontal cortex) were quantified using liquid chromatography tandem mass spectrometry (LC/MS). Cyfluthrin disposition was best described by the use of a two-compartment open model. When given orally, plasma kinetics showed an extensive oral absorption of cyfluthrin and a slow elimination. The area under the concentration-time curve [AUC (0–24h)] and maximal plasma concentration (Cmax) were 6.11 ± 1.06 mg h/L and 0.385 ± 0.051 μg/mL, respectively; β phase elimination half-life (T1/2β) was (17.15 ± 1.67 h). Oral bioavailability was found to be 71.60 ± 12.36%. After oral administration, cyfluthrin was widely distributed to brain tissues. AUC (0–24h) was significant higher in all tested brain tissues than in plasma. The largest discrepancy was found for hypothalamus. AUC (0–24h), Cmax and T1/2β in hypothalamus were 19.36 ± 2.56 mg h/L, 1.21 ± 0.11 μg/g and 22.73 ± 1.60 h, respectively. Assuming the identified toxicokinetics parameters, this study serves to better understand mammalian toxicity of pyrethroid cyfluthrin and to design further studies to characterize its neurotoxicity. •Toxicokinetics of cyfluthrin after single oral and intravenous (IV) doses were determined in male Wistar rats.•Serial plasma and brain tissue samples were collected and analysed to quantify cyfluthrin concentrations by LC/MS.•Cyfluthrin kinetic disposition after IV and oral doses was best described by the use of a two-compartment open model.•When administered orally, cyfluthrin was extensively absorbed, distributed to brain tissues and slowly eliminated.•Cyfluthrin brain accumulation, mainly in hypothalamus, was observed; Cmax in hypothalamus was 3.3 times higher than in plasma.