FCR-1272

Overview

Chemical Names
(RS;SR)-alpha-CYANO-4-FLUORO-3-PHENOXYBENZYL(1RS,3RS:1RS,3SR)-3-(2,2-DICHLOROVINYL)-2,2-DIMETHYLCYCLOPROPANECARBOXYLATE; CYANO(4-FLUORO-3-PHENOXYPHENYL)METHYL-3-(2,2-DICHLOROETHENYL)-2,2-DIMETHYLCYCLOPROPANECARBOXYLATE
Synonyms
BAYTHROID; CYFOXYLATE
CAS number
68359-37-5
Functional Class
Veterinary Drug
INSECTICIDE

Evaluations

Evaluation year: 1998

ADI:
0-0.02 mg/kg bw

Comments:
The Committee concluded that the effects most relevant for the toxicological evaluation of cyfluthrin were those observed in the long-term study in rats fed the compound in the diet. The NOEL was 50 mg/kg in feed, equal to 2 mg/kg bw per day, on the basis of depression of body-weight gain. Using this NOEL and a safety factor of 100, the Committee established an ADI for cyfluthrin of 0-20 µg/kg bw (1.2 mg/p/d for 60-kg person). The Committee also established the following MRLs: Muscle, liver and kidney (cattle): 0.02 mg/kg; Fat (cattle): 0.2 mg/kg; Milk (cattle): 0.04 mg/l. The TMDI based on those MRLs is 79 µg/p/d for a 60-kg adult, 6.6% of the ADI.
MRL Comment:
MRLs: Muscle, liver and kidney (cattle): 0.02 mg/kg; Fat (cattle): 0.2 mg/kg; Milk (cattle): 0.04 mg/l
MRL Code:
MRL
Intake:
TMDI: 79 µg/p/d, 60-kg adult
Meeting:
48
Report: 
TRS 879-JECFA 48/46
Tox Monograph: 
FAS 39-JECFA 48/79
Residues: 
FNP 41/10-JECFA 48/9

Toxicological study

Pivotal Study:
2-year dietary carcinogenicity study (Suberg & Loser, 1983b): SPF BOR:WISW rats (n=65/sex/group) received a diet containing 50, 150, or 450 mg/kg cyfluthrin premixed with Wessalon S for two years ad libitum. Significantly decreased body-weight gain was noted, starting at 150 mg/kg. N-Demethylase activity was increased by 30% in males and 20% in females after seven days at the high dose. Induction of the microsomal enzyme N-demethylase in rats at the high dose is considered not to be of toxicological relevance as no specific morphological alteration or damage to the liver was seen at histopathological examination. The incidence of tumours was not altered by treatment at any dose. The NOEL was 50 mg/kg feed, equal to 2 mg/kg bw per day. .
Animal Specie:
Rat
Effect:
Depressed bodyweight gain
NOEL:
2 mg/kg bw per day
Point of departure:
2 mg/kg bw per day