Summary of Toxicological Studies on Acequinocyl

Abstract

Safety evaluation of Acequinocyl was conducted via comprehensive studies. Acute toxicity is very low in every exposure route for both Acequinocyl and the 15% SC formulation. Primary irritation potential of Acequinocyl 15% SC formulation is minimal for eyes and nil for skin. Acequinocyl 15% SC formulation has no skin sensitization potential. In long term studies, hemorrhagic changes and/or prolonged blood clotting time were observed in rats treated with high doses of Acequinocyl. Similar changes were also observed in pharmacology studies in which rats dosed with a single high dose of Acequinocyl showed increased fibrinogen level and prolonged blood clotting time. As Acequinocyl has a chemical structure similar to that of vitamin K, it is assumed that Acequinocyl competes against vitamin K in the mechanism of blood coagulation in rats. No effect on reproductive ability was observed in rats. In teratogenicity studies, no teratogenic effect was observed even in the highest doses that induced embryotoxic changes. No mutagenic effect was observed in genetic toxicity studies, and no specific non-neoplastic/neoplastic lesions were observed in chronic studies. ADI value for Acequinocyl was established at 0.027 mg/kg/day based on the NOAEL in the 80-Week Carcinogenicity Study In Mice. Maximum residue levels on crops established by the Japanese Ministry of Health and Welfare are 1 ppm for eggplants, 0.5 ppm for cucumbers and gherkins, 0.1 ppm for watermelons and melons, 0.2 ppm for mandarin oranges, 2 ppm for natsudaidai, 1 ppm for lemons and other citrus fruits than mandarin oranges and natsudaidai, 1 ppm for apples, 2 ppm for pears and Japanese pears, 0.1 ppm for peaches, 1 ppm for plums and prunes, 2 ppm for cherries and 0.5 ppm for grapes. Acequinocyl 15% SC formulation is considered to be a useful agent in the agricultural field on account of its excellent acaricidal effect and minimal risk to humans and the environment when used in accordance with the instructions. © 2001, Pesticide Science Society of Japan. All rights reserved.