N-butyl 4-oxopentanoate

Endpoint summary

Description of key information

LD50 (oral) > 2000 mg/kg bw (rat, female)

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

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

Τhe acute otal toxicity was evaluated based on data on Similar Substance 2. Justification for Read Across is given in Section 13 of IUCLID.

Acute toxicity: oral

The potential toxic effect of the test item when administered as a single oral dose to Wistar rats was evaluated according to the OECD Guideline 423. One group of 3 females was dosed. Test item-related mortality was not observed during 24 hours and therefore, in a second step, another 3 females were treated at the same dose. Animals were observed individually immediately after administration of the test item and 0.5, 1, 2, and 4 hours later. Each animal was inspected daily for the next 14 days after which, all animals were killed and subjected to necropsy examination. Individual weights of animals were measured immediately prior to administration of the test item and weekly thereafter.

The test item administered to 6 females at a limit dose did not cause death. No signs of toxicity were observed during the first 4 hours in females or the 14-day observation period thereafter. The body weights of all animals increased during the study. No body weight losses were observed between the first and second week after administration. During necropsy, no macroscopic findings were observed.

LD50 (rat, female) > 2000 mg/kg bw

Acute toxicity: inhalation

No data has been provided for the inhalation route as the oral and dermal routes have been identified as more appropriate for exposure, in accordance with (EC) No. 1907/2006 (REACH Regulation), Annex VIII, Column 2, point 8.5. In addition, as per the Information Requirements R7a (ECHA, 2017) testing by the inhalation route is the default route for gases and the preferred route for liquids of high to very high vapour pressure at ambient temperature (>25 kPa or boiling point below 50 °C) for which inhalation is usually the predominant route of human exposure. The substance has a lower vapour pressure (0.011 kPa) and a higher boiling point (205.8 °C) suggesting that the inhalation exposure is considered as unlikely.

Furthermore, no systemic toxicity occurred during the acute oral toxicity test; the absence of systemic toxicity and the absence of other data that could indicate the potential for absorption following ingestion, support the idea that it is unlikely that the substance will be absorbed in case it is inhaled. The properties of the substance and the absence of systemic toxicity in the oral toxicity test indicate that human exposure is not possible via inhalation, therefore testing via this route for acute toxicity should not be conducted.

Acute dermal toxicity

The physicochemical properties of the substance suggest a low dermal absorption in case of dermal exposure. Furthermore, in a study by Moore et al. (2013) the acute systemic toxicity data (LD50 values) and hazard classifications derived in the rat following oral administration and dermal application have been analysed to examine whether or not orally-derived hazard classification or LD50 values can be used to determine dermal hazard classification. The authors suggest that no substance (out of the 355 substances reviewed) with an oral LD50 of >2000 mg/kg was classified for acute systemic toxicity by the dermal route, suggesting that dermal testing for acute systemic toxicity of such substances adds nothing to the hazard characterisation and should be removed from routine regulatory data requirements. Considering that the substance presents an oral LD50 > 2000 mg/kg bw, testing via the dermal route for acute toxicity should not be conducted.

Justification for classification or non-classification

The LD50 of the substance in the acute oral toxicity study is greater than 2000 mg/kg bw.

Acute toxicity hazard categories and acute toxicity estimates (ATE) are defined by the respective categories:

		Danger	Danger	Danger	Warning
	Unit	Category 1	Category 2	Category 3	Category 4	No Classification
ORAL	mg/kg bw	LD50 ≤ 5	5 < LD50 ≤ 50	50< LD50 ≤ 300	300< LD50 ≤ 2000	LD50> 2000

Considering the LD50, the substance does not meet the classification criteria of the (EC) N. 1272/2008 (CLP Regulation), and thus is not classified for acute toxicity