CYPERMETHRIN

Overview

Chemical Names
(RS)-alpha-CYANO-3-PHENOXYBENZYL-(1RS,3RS,1RS,3RS)-3-(2,2-DICHLOROVINYL)-2,2-DIMETHYLCYCLOPROPANE CARBOXYLATE (IUPAC); (RS)-CYANO(3-PHENOXYPHENYL)METHYL(1RS)-cis-trans-3-(2,2-DICHLOROETHENYL)-2,2-DIMETHYLCYCLOPROPANE CARBOXYLATE (CAS)
CAS number
52315-07-8
Functional Class
Veterinary Drug
INSECTICIDE

Evaluations

Evaluation year: 2004

ADI:
0-0.02 mg/kg/d

Comments:
Cypermethrin typically contains 20–40% α-cypermethrin, which are the two most toxicologically active isomers of cypermethrin. As the ratio of isomers in commercial cypermethrin products is variable, the toxicity of these products also varies. JECFA concluded that as α-cypermethrin alone and cypermethrin are qualitatively similar in their toxicity and metabolism, and in view of the fact that cypermethrin includes a substantial proportion of α-cypermethrin, the ADI of 0-0.02 mg/kg bw/d previously established for α-cypermethrin could apply for both substances. The Committee reconfirmed the NOEL for α-cypermethrin of 1.5 mg/kg bw per day on the basis of a 52-week study in dogs fed with a-cypermethrin, as identified at the forty-seventh meeting. The Committee established a group ADI of 0–0.02 mg/kg bw for cypermethrin and a-cypermethrin, using a safety factor of 100 and by rounding up. The Committee recommended the following MRLs, expressed as the total of cypermethrin residues: muscle, liver and kidney, 50µg/kg; fat, 1000µg/kg; and milk, 100µg/kg, based on the limits of quantitation of the new methods, considering that the concentration of residues in both cattle and sheep tissues was ≤35 µg/kg. The MRLs for fat and cows’ milk were based on residue depletion data. These MRLs replace those previously recommended and apply to both cattle and sheep. These recommended MRLs would result in a maximum daily intake of 368 µg of residues as cypermethrin equivalents, or 30% of the upper bound of the ADI for a 60 kg person. The exposure to cypermethrin from use of pesticides, as estimated by JMPR, is approximately 300µg. The total theoretical exposure for the cypermethrins would therefore be approximately 650µg.
MRL Comment:
MRLs (total of cypermethrin residues resulting from the use of cypermethrin or alpha-cypermethrin as veterinary drugs): Muscle, liver, and kidney (cattle and sheep): 0.05 mg/kg; fat (cattle and sheep): 1 mg/kg; milk (cattle): 0.1 mg/kg
MRL Code:
TMRL
Intake:
Maximum daily intake of 368 µg cypermethrin equivalents/p/d (tissue residues) + 300 µg/p/d (pesticide use) = 650 µg/p/d.
Meeting:
62
Report: 
TRS 925-JECFA 62/12
Tox Monograph: 
FAS 53-JECFA 62/91
Specification: 
FNP 41/16-JECFA 62/11

Toxicological study

Pivotal Study:
52-week dog study (Dean & Jackson, 1995): Beagle dogs (4/sex/group) received via the diet 0, 60, 120 or 240 mg alpha-cypermethrin/kg feed dally for 52 weeks. Two males at 240 mg/kg developed skin reddening on the tail. Abdominal skin reddening and alopecia were seen in another male at 240 mg/kg and one female at 120 mg/kg. The tail reddening caused obvious irritation and resulted in ulceration and necrosis in one male leading to amputation of part of the tail. The NOEL was 60 mg/kg feed, equivalent to 1.5 mg/kg bw per day.
Animal Specie:
Dog
Effect:
Skin reddening on the tail, abdominal skin reddening and alopecia
NOEL:
1.5 mg/kg bw/d
Point of departure:
1.5 mg/kg bw/d
Previous Years:
2002, TRS 911-JECFA 58/37, FAS 38-JECFA 47/133 (1996), FNP 41/14-JECFA 58/15. 0-0.05 mg/kg bw (1996). MRLS, AS CYPERMETHRIN: MUSCLE, LIVER AND KIDNEY (SHEEP): 0.02 mg/kg; FAT (SHEEP): 0.2 mg/kg. FU. MRL 2000, TRS 900-JECFA 54/41, FNP 41/13-JECFA 54/19, FAS 38-JECFA 47/133 (1996). 0-0.05 mg/kg bw (1996). THE TEMPORARY MRLs RECOMMENDED AT THE FORTY-SEVENTH MEETING (1996) WERE NOT EXTENDED AS THE INFORMATION REQUIRED BY THE FIFTH-FOURTH MEETING (2000) WAS NOT PROVIDED AND THERE WAS NO INDICATION THAT IT WOULD BE PROVIDED IN THE FUTURE. FU. NOT EXTENDED 1996, TRS 876-JECFA 47/44, FNP 41/9-JECFA 47/4, FAS 38-JECFA 47/133. 0-0.05. MRLS (TEMPORARY; EXPRESSED AS PARENT DRUG): MUSCLE, LIVER AND KIDNEY (CATTLE, SHEEP AND CHICKENS): 0.2 mg/kg; FAT (CATTLE, SHEEP AND CHICKENS): 1 mg/kg; EGGS (CHICKENS): 0.1 mg/kg; MILK (CATTLE): 0.05 mg/l. FU. TMRL
2002, TRS 911-JECFA 58/37, FAS 38-JECFA 47/133 (1996), FNP 41/14-JECFA 58/15. 0-0.05 mg/kg bw (1996). MRLS, AS CYPERMETHRIN: MUSCLE, LIVER AND KIDNEY (SHEEP): 0.02 mg/kg; FAT (SHEEP): 0.2 mg/kg. FU. MRL 2000, TRS 900-JECFA 54/41, FNP 41/13-JECFA 54/19, FAS 38-JECFA 47/133 (1996). 0-0.05 mg/kg bw (1996). THE TEMPORARY MRLs RECOMMENDED AT THE FORTY-SEVENTH MEETING (1996) WERE NOT EXTENDED AS THE INFORMATION REQUIRED BY THE FIFTH-FOURTH MEETING (2000) WAS NOT PROVIDED AND THERE WAS NO INDICATION THAT IT WOULD BE PROVIDED IN THE FUTURE. FU. NOT EXTENDED 1996, TRS 876-JECFA 47/44, FNP 41/9-JECFA 47/4, FAS 38-JECFA 47/133. 0-0.05. MRLS (TEMPORARY; EXPRESSED AS PARENT DRUG): MUSCLE, LIVER AND KIDNEY (CATTLE, SHEEP AND CHICKENS): 0.2 mg/kg; FAT (CATTLE, SHEEP AND CHICKENS): 1 mg/kg; EGGS (CHICKENS): 0.1 mg/kg; MILK (CATTLE): 0.05 mg/l. FU. TMRL