Methyl pyruvate

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

other: Secondary source ECHA disseminated Dossier for CAS 687-47-8

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Data source

Reference

Reference Type:

secondary source

Title:

ECHA disseminated dossier for CAS 687-47-8

Author:

ECHA

Year:

2016

Bibliographic source:

Study 1995 cited in ECHA disseminated dossier for CAS 687-47-8; Status Dec. 2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

the observation period lasted 15 days instead of 14 days

GLP compliance:

yes (incl. QA statement)

Test type:

other: standard acute method

Limit test:

yes

Test animals

Species:

rat

Strain:

other: SPF-reared, Wistar derived rats

Sex:

male/female

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

actual concentation of ethyl lactate in the test atmosphere turned out to be 5.4 ± 0.4 g/m³. The nominal concentration was 17.6 g/m³. From the determination of the particle size distribution it appeared that no aerosol could be shown. This does not necessarily mean that there were no droplets in the test atmosphere, since it is very likely that after deposition of the droplets in the impactor the ethyl lactate has evaporated. Actually, the large difference between actual and nominal concentration points to loss of test material, which at this high concentration level only is observed during aerosol exposures.

No. of animals per sex per dose:

5

Control animals:

no

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.4 mg/L air (analytical)

Exp. duration:

4 h

Effect levels 2

Sex:

male/female

Dose descriptor:

LC0

Effect level:

5.4 mg/L air

Exp. duration:

4 h

Mortality:

None of the rats died during or after exposure.

Clinical signs:

other: During the entire exposure the animals showed a decreased breathing frequency. Wet noses were seen after 30 minutes of exposure and piloerection after 60 minutes. Half closed eyes and lachrymation were all observed only at 15 minutes after the start of th

Body weight:

Body weight gain was not visibly affected by the exposure. All animals gained weight in a normal way.

Gross pathology:

Gross-examination at autopsy revealed pale lungs in one male and three females. In three females the lungs showed a few petechiae.

Applicant's summary and conclusion

Conclusions:

The 4-hour LC50 of ethyl lactate in rats is higher than 5.4 g/L. No clear information given on type of inhalative exposure (i.e. aerosol vs. vapour). Based on this uncertainty, the given LC50 cannot be applied for an overall classification decision due to the fact that criteria differ between aerosol and vapour exposure.

Executive summary:

Based on chosen study conditions, the LC50 of ethyl lactate is greater than 5.4 mg/L. Based on the structural similarity concerning the alkyl residue (methyl- vs. ethyl group) between Ethyl-S-lactate and Methylpyruvate and their close metabolic relationship (bilateral biotransformation between pyruvate and lactate via the lactate dehydrogenase), a similar outcome for methylpyruvate is considered, however, based on uncertainties in the type of inhalation exposure (i.e. aerosol vs. vapour), the given LC50 cannot be applied for an overall classification decision due to the fact that criteria differ between aerosol and vapour exposure.