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Description of key information

Acute oral toxicity study in rats (OECD Guideline 401): LD50 = 2,000-5,000 mg/kg in both males and females.

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:
High quality since a reliable study in accordance with OECD Guideline 401 is available.

Acute toxicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Oral Acute Toxicity

The key oral acute toxicity study of methyl 2-hydroxybutyrate (KS_Acute toxicity: oral_rat_1993) was conducted in rats according to OECD Guideline 401.

Briefly, the test substance methyl 2-hydroxybutyrate was administered by gavage to male and female SD rats (SPF) to determine its lethal dose and evaluate its acute toxicity.

The LD50 was estimated to be 2,000-5,000 mg/kg in both males and females.

In the monitoring of general signs and symptoms, both males and females from the 5000 mg/kg group showed staggering gait 5-30 min after administration. Two males from this group died 10 min after administration after showing increased body muscle tone. Other males and females gradually showed sedation and body drooping, and some of them died within 24 hrs after showing collapse.

Both males and females from the 50-2000 mg/kg groups showed no changes in general symptoms. Body weight decreased in females from the 5000 mg/kg group 2 days after administration, but normal weight gains were observed thereafter. Males showed no abnormality. Necropsy revealed congestion and hemorrhage in the lungs and white color changes in the liver and duodenal mucosa in dead males and females, but surviving animals showed no particular abnormality at the end of the study.

Justification for classification or non-classification

Based on the LD50 range from >2000 - <= 5000 mg/kg bw determined in the acute oral toxicity study in rats the test item methyl 2-hydroxyisobutyrate was considered weakly toxic in rats. Therefore the test item does not meet the classification criteria of Regulation (EC) No 1272/2008 (CLP Regulation).

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