Pesticide residues in food — 2006: Toxicological ... - ipcs inchem

104
5. Studies on metabolites ....................................................................... 139
Comments ....................................................................................................... 140
Toxicological evaluation ................................................................................. 143
References ....................................................................................................... 146
Explanation
Cyfluthrin, the International Organization of Standardization (ISO) approved common name
for 3-(2,2-dichloro-vinyl)-2,2-dimethyl-cyclopropane-carboxylic acid cyano-(4-fluoro-3-phenoxyphenyl)-methyl
ester(RS), is a synthetic cyano-containing pyrethroid insecticide. It was evaluated by the
JMPR in 1987, when an acceptable daily intake (ADI) of 0–0.02 mg/kg bw was established based on a noobserved-adverse-effect
level (NOAEL) of 50 ppm, equal to 2 mg/kg bw per day, which was identified on the
basis of reduced body-weight gains in a 2-year study in rats and using a safety factor of 100. In 1997, the Joint
FAO/WHO Expert Committee on Food Additives (JECFA) also established an ADI of 0–0.02 mg/kg bw.
Technical-grade cyfluthrin consists of a mixture of four diastereomeric pairs of enantiomers
(giving rise to eight optical isomers), consisting of two cis and two trans isomeric pairs. Betacyfluthrin
consists of two diastereoisomeric pairs, which are the biologically active isomers of
cyfluthrin. They are contained in cyfluthrin at a concentration of about 40%.
Cyfluthrin was re-evaluated by the present Meeting within the periodic review programme
of the Codex Committee on Pesticide Residues (CCPR). Beta-cyfluthrin has not been evaluated
p reviously. The Meeting reviewed new data on cyfluthrin and beta-cyfluthrin that had not been considered
previously, and relevant data from the previous evaluation.
For cyfluthrin, the specifications were established by the FAO/WHO Joint Meeting on Pesticide
Specifications (JMPS) and published as WHO specifications and evaluations for public health pesticides:
cyfluthrin (2004). 1
Not all pivotal studies with cyfluthrin were certified as being compliant with good laboratory
practice (GLP). These studies were carried out before the Organisation for Economic Co-operation and
Development (OECD) guidelines on GLP were promulgated. However, the quality of these studies was
considered to be acceptable.
Figure 1. Chemical structure of beta-cyfluthrin
Cl
Cl
O CN
C O CH F
α
3 1
O
H C CH 3 3
1
Available from http://www.who.int/whopes/quality/en/Cyfluthrin_spec_eval_WHO_Nov_2004.pdf
CYFLUTHRIN AND BETA-CYFLUTHRIN X-X JMPR 2006