TABLE 1

Pharmacokinetic data from plasma for (A) fipronil and (B) fipronil sulfone in male rats

Data are expressed as means ± S.D. (n = 6).

Pharmacokinetic ParameterFipronil (1 mg/kg, i.v.)Fipronil (3 mg/kg, Oral)Fipronil (10 mg/kg, Oral)Fipronil (30 mg/kg, Oral)P Value
Fipronil
 t1/2 (h)2.66 ± 0.5612.16 ± 5.219.16 ± 11.284.44 ± 1.190.207
Tmax (h)0.83 ± 0.001.75 ± 0.882.17 ± 0.753.17 ± 1.470.098
Cmax (ng/ml)100.5 ± 39.658.81 ± 1.91a23.76 ± 9.21b47.62 ± 20.16<0.001*
AUClast (h ng/ml)125.0 ± 20.6672.26 ± 16.80a172.4 ± 48.02b454.3 ± 186.2<0.001*
AUC(h ng/ml)153.8 ± 17.90119.4 ± 16.19a204.6 ± 42.84b481.3 ± 197.1<0.001*
CL/F (l/h per kilogram)6.58 ± 0.8225.50 ± 3.46a,c50.84 ± 11.2970.36 ± 24.280.001*
MRT (h)3.34 ± 0.8817.32 ± 6.6312.98 ± 11.948.30 ± 1.390.177
Bioavailability (%)19.28 ± 4.48a13.80 ± 3.8412.12 ± 4.970.035*
Fipronil sulfone
Tmax (h)1.75 ± 0.424.00 ± 1.10a6.33 ± 3.20b14.00 ± 2.19<0.001*
Cmax (ng/ml)27.66 ± 6.6518.74 ± 11.56a,c56.92 ± 18.28b152.5 ± 35.62<0.001*
AUClast (h ng/ml)130.35 ± 25.92286.7 ± 146.4a,c1052 ± 414.1b3005 ± 671.6<0.001*
Biotransformation (%)104.8 ± 14.88400.8 ± 197.4608.4 ± 197.8730.4 ± 257.70.058
  • MRT, mean residence time from time zero to infinity.

  • * P < 0.05 compared with the 3, 10, and 30 mg/kg, oral, fipronil groups.

  • a P < 0.05 compared with the 3 and 30 mg/kg, oral, fipronil group.

  • b P < 0.05 compared with the 10 and 30 mg/kg, oral, fipronil group.

  • c P < 0.05 compared with the 3 and 10 mg/kg, oral, fipronil group.