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Description of key information

Acute oral toxicity:
- oral: LD50 >2000 mg/kg bw (rat, OECD 423), LD50 >5000 (rat)
- dermal: LD50 >5000 mg/kg bw (rat)

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
Value:
5 000 mg/kg bw

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
Value:
5 000 mg/kg bw

Additional information

Oral

The oral acute toxicity of methylionone was tested in a study under GLP performed according to OECD Guideline 423 (BASF, 1999). Three male and three female Wistar rats were once administered by gavage with 2000 mg/kg bw in 5 ml/kg bw olive oil DAB 10. The following observation time was 17 days for males and 14 days for females. Although signs of toxicity were noted during the first days after application, the animals appeared normal after five days. Since no mortality was observed, the NOAEL could be determined as >2000 mg/kg bw.

In another study ten rats were administered orally with 5000 mg/kg bw (Moreno, 1973). As no mortality occurred within the 14 day post dosing observation time, the LD50 values was found to be >5000 mg/kg bw. Although no further data were given, this study was evaluated reliable as it is cited by the FFHPVC Terpene Consortium and the original data are from highly experienced and respected toxicologists.

In a third study, ten rats (5 males, 5 females) were administered 5000 mg/kg bw orally (Givaudan, 1978). No deaths were observed within 14 days, thus the LD50 was determined to be >5000 mg/kg bw/day. The dose for the LD50 study had previously been determined in a range-finder test, in which 4 male and 4 female rats were adminstered 0.5, 1, 2, or 5 g/kg bw, no deaths were observed within 14 days (Givaudan, 1978).

In an acute oral range-finding toxicity test, individually housed mice aged 4-5 weeks were fasted for 4 hours and then orally intubated with 2, 5, or 10  ml/kg bw of undiluted test substance (2, 6 and 2 mice, respectively) (Quest, 1980). The mice were observed up to 7 days following treatment and dying mice were necropsied. All mice surviving to the end of the observation period were weighed, killed and examined post mortem. Due to observed mortality in the 5 and 10 ml/kg bw groups (1/6 and 2/2 respectively), the LD50 was calculated to be >5 and < 10 ml/kg bw and the methylionone was given a toxicity rating according to Hodge and Sterner’s classification.

Dermal

For evaluating the acute dermal toxicity, a concentration of 5000 mg/kg bw was tested in eight rabbits (Moreno, 1973). Since no mortality was observed during the 14 day observation period, the LD50 was determined as >5000 mg/kg bw. Although the report was short, this study was evaluated reliable as it is cited by the FFHPVC Terpene Consortium and the original data are from highly experienced and respected toxicologists.

Justification for classification or non-classification

Due to the results from different studies including one performed according to OECD Guideline 423, no classification is required.