TABLE 4

CLint and percentage oxidative and hydrolytic metabolism of Type I pyrethroids from rat and human hepatic microsomes

Pyrethroid
Isomer
Species
CLint
Percentage Oxidative
Percentage Hydrolytic
Bifenthrin 100% cis Rat 224 ± 20a 100 N.S.b
Human 20 ± 6 100 N.S.b
S-Bioallethrin 100% trans Rat 1218 ± 106 100 N.D.c
Human 74 ± 5 100 N.D.c
Bioresmethrin 96% trans Rat 1515 ± 367 57 43
2% cis Human 334 ± 102 N.S.d 100
cis-Permethrin 100% cis Rat 529 ± 19 100 N.S.b
Human 52 ± 12 100 N.S.b
trans-Permethrin 96% trans Rat 438 ± 46 35 65
4% cis
Human
636 ± 53
59
41

  • N.S., no significant difference; N.D., not detected.

  • ↵ a Values are ml/min/kg b.wt. ± S.D., for three pooled microsomal samples microsomes.

  • ↵ b The clearance value for hydrolysis (in the absence of NADPH) was not significantly different from 0 as assessed by a one-sample t test, p < 0.05.

  • ↵ c No metabolism was detected in the absence of NADPH.

  • ↵ d The clearance values in the presence or absence of NADPH were not significantly different as assessed by an unpaired t test, p < 0.05.