Isofetamid (Pesticides)

The Food Safety Commission of Japan (FSCJ) conducted a risk assessment of isofetamid (CAS No. 875915-78-9), a phenacyl amide fungicide, based on results from various studies. Major treatment-related effects of isofetamid were observed on liver (hepatocellular hypertrophy) and on thyroid (hypertrophy of follicular epithelial cell). None of neurotoxicity, carcinogenicity, reproductive toxicity, teratogenicity, immunotoxicity and genotoxicity were observed. Based on the results from various studies, only parent isofetamid was identified as the relevant substance to the residue definition for dietary risk assessment in agricultural products. The lowest no-observed-adverse-effect level (NOAEL) obtained in all the toxicity studies was 5.34 mg/kg bw/day in a one-year chronic toxicity study in dogs. FSCJ has established an acceptable daily intake (ADI) of 0.053 mg/kg bw/day, applying a safety factor of 100 to the NOAEL. The lowest NOAEL for adverse effects that would be likely to be elicited by a single oral administration of isofetamid was 300 mg/kg bw/day, which is obtained on the maternal toxicity in rabbits. FSCJ specified an acute reference dose (ARfD) of 3 mg/kg bw/day, applying a safety factor of 100 to the NOAEL.