[A 28-day repeated dose toxicity test of Phoxim in Wistar rats].

A 28-day oral toxicity test of Phoxim was carried out in male and female Slc: Wistar rats given dose levels of 0, 7.5, 75 and 750 mg/kg/day by gavage. A 14-day recovery test was conducted for animals receiving the 750 mg/kg dose level. There were no deaths with any dose and food consumption and growth were not affected. No specific changes were observed in any of the hematological parameters investigated. At the 750 mg/kg level, significant increases of liver, kidney, and adrenal gland weights were observed in both sexes, which persisted throughout the recovery period. Hepatic lesions with necrosis and swelling of hepatocytes were also observed with the highest dose, but these changes appeared to be reversible because they were no longer present after the recovery period. At doses of 7.5 mg/kg and above, remarkable inhibition of the serum cholinesterase activity was observed in both sexes. This persisting in female rats after the recovery period. Based on these results, the no-observed-effect level (NOEL) was concluded to be less than 7.5 mg/kg/day under the present experimental conditions.