Page 550 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Pyrethrins and Pyrethroids Chapter | 39 517

VetBooks.ir Cl C Cl O Cl C Cl O

HC
C
HC
O
C
O
C N
CH 2 HC
H C CH 3 O H C CH 3 O
3
3
Permethrin Cypermethrin
CH 3
F (Z )-(1R)-cis-acid
F H C C O
3
C H O
HC C O CH
F C C C O 3
CH 3 C N
Cl HC
H H H C CH 3 CH 2 CH CH 2
CH 3 O 3 O
Allethrin

Cl
H H
Cl CH 3 (Z )-(1S)-cis-acid
Cl C
C C C O
F C N CH O
CH
C H 3 O HC O
F C
F O CH F
O H C
3
CH 3
C N
Cyhalothrin
Flumethrin
CH 3
H C N
3
C O
C
O
Br (S)-alcohol (1R)-cis-acid
Cl
Br C O
CH C O Cl
C N
CH 3
C O F
H
H H
CH 3 O
Deltamethrin Cyfluthrin
FIGURE 39.1 Structures of selected pyrethrins and pyrethroids.

produce a high degree of selective toxicity. This is the TOXICITY
reason that the toxicity of different batches of pyrethroids
Dermal exposure to pyrethroids is most common (Osweiler,
can vary from batch to batch. The rat oral LD 50 of com-
1996; Gammon et al., 2012; Anadon et al., 2013). In
mercial permethrin can vary from 430 to 8900 mg/kg,
humans, the bioavailability of pyrethroids applied dermally
with toxicity depending on the amount of cis isomer pres-
is approximately 1%. Absorption after oral exposure in
ent in the batch.