Acetic acid, 2-[(5-chloro-8-quinolinyl)oxy]-

Endpoint summary

Description of key information

Cloquintocet acid is of low acute oral, inhalation and dermal toxicity. The acute oral LD50 in the rat is >2000 mg/kg bw. The acute 4-hour inhalation LC50 in the rat is >6.11 mg/L. The acute dermal LD50 in the rat is >5000 mg/kg bw.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Klimisch score = 1. Modern study compliant with current test guidelines and GLP

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

6 110 mg/m³

Quality of whole database:

Klimisch score = 1. Modern study compliant with current test guidelines and GLP

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Quality of whole database:

Klimisch score = 1. Modern study compliant with current test guidelines and GLP

Additional information

Acute Oral Toxicity:

The acute oral toxicity of cloquintocet acid was determined according to OECD test guideline 423 (Verma, 2013d).

Two sets of fasted Wistar rats (3 females/set) were given a single oral dose of test substance in 0.5% (w/v) carboxy methyl cellulose (CMC) in distilled water at a dose of 2000 mg/kg bw and were observed for 14 days. There were no treatment-related mortality, clinical signs or changes in body weight recorded. Necropsy findings of the terminally sacrificed rats did not reveal any abnormality of pathological significance. The acute oral LD50 was found to be greater than 2000 mg/kg bw.

 

Acute Inhalation Toxicity:

The acute inhalation toxicity of cloquintocet acid was determined according to OECD test guideline 403 (Verma, 2013e).

A group of 5 male and 5 female Wistar rats were exposed to a time-weighted average (TWA) concentration of 6.11 mg cloquintocet acid/L air (limit test) using a nose-only inhalation exposure system. The rats were exposed for 4 hours followed by a 14-day post-exposure observation period. The mass median aerodynamic diameter (MMAD) of aerosolized test substance was determined to be 2.37 μm with an average geometric standard deviation (GSD) of 2.42. There was no treatment-related mortality, no clinical signs of toxicity, no effects on body weight changes, and no abnormalities observed at necropsy. The 4 hour acute inhalation LC50 was found to be greater than of 6.11 mg/L.

 

Acute Dermal Toxicity:

The acute dermal toxicity of cloquintocet acid was determined according to OECD test guideline 402 (Verma, 2013f).

A group of Wistar rats (5 males and 5 females) were dermally exposed to the test substance for 24 hours following application at a limit dose of 5000 mg/kg body weight. The required quantity (1111.5 to 1457.5 mg) of test item (moistened with 0.2 mL distilled water) was applied over the clipped area (approximately 7 × 5 cm body surface area) and the rats were observed for a period of 14 days. There were no treatment-related mortality, clinical signs, changes in body weight or necropsy findings recorded. The acute dermal LD50 was found to be greater than 5000 mg/kg bw.

Justification for classification or non-classification

Cloquintocet acid is of low acute oral toxicity (LD50 >2000 mg/kg bw), low acute inhalation toxicity (4 -h LC50 > 6.11 mg/L) and low acute dermal toxicity (LD50 >5000 mg/kg bw). Cloquintocet acid does not meet the criteria for classification for acute toxicity according to the CLP Regulation 1272/2008.