N-methylacetamide

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

pre GLP, no further details about test substance, post-exposure period 7 days

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1970

Report date:

1970

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1970

Report date:

1970

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

observation period 7 days

Principles of method if other than guideline:

BASF test; study is comparable with the inhalation hazard test described in the Annex of OECD Guideline 403 (adopted 1981)

GLP compliance:

no

Test type:

other: IHT (inhalation hazard test)

Test material

Test material information

Constituent 1

Reference substance name:

N-methylacetamide

EC Number:

201-182-6

EC Name:

N-methylacetamide

Cas Number:

79-16-3

Molecular formula:

C3H7NO

IUPAC Name:

N-methylacetamide

Details on test material:

- Name of test material (as cited in study report): Monomethylacetamid
- Physical state: solid
- Analytical purity: 99.9 %

Test animals

Species:

rat

Strain:

not specified

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Gassner (breeder)
- Mean weight at study initiation: 157 g (males), 163 g (females)

ENVIRONMENTAL CONDITIONS
not reported

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

Three rats per sex exposed for 8 h, respectively, to an atmosphere that has been saturated at 50°C with the volatile part of the compound. At 50 °C the substance is fluid.
Vapour was generated by bubbling 200 l/h dry air (no CO2) through the liquid substance column (volume ca. 50 ml) of about 5 cm above a fritted glass disc in a glass cylinder. The glass cylinder was heated in a oil bath. The air pressure was 760 mm Hg. Temperature in the exposure chamber was 20°C.
No analytical determination of the atmosphere concentrations was performed. The nominal concentration usually can be calculated as quotient of the amount of test substance weight loss during the exposure, which is given in the raw data, and the amount of air used during the exposure. The study allows for an estimate of the length of time required to cause severe toxic effects resulting from exposure to an atmosphere saturated with volatile components of the test substance.

Mean used test substance of two experiments: (3.90 g + 3.14 g) / 2 = 3.52 g
Air volume per experiment: 1600 l for 8 h with 200 l/h
--> 3.52 g/1600 l = 2.2 mg/L
This experimental value of 2.2 mg/L used test substance is in line with the calculated saturated vapour concentration of 3 mg/l at 49.3°C (0.0412 * MG * VP[hPa] = 0.0412 * 73.09 * 1 haP).

Duration of exposure:

8 h

Concentrations:

2.19 mg/L nominal

No. of animals per sex per dose:

6

Control animals:

no

Details on study design:

- Duration of observation period following administration: 7 days
- Frequency of observations and weighing: Body weight at the beginning and at the end of the study. Observation was several times at the day of exposure and presumably daily exception of weekends and holidays afterwards.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs

Statistics:

none

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

other: IHT

Effect level:

2.19 mg/L air (nominal)

Exp. duration:

8 h

Remarks on result:

other: no mortality

Mortality:

0/12 animals died

Clinical signs:

other: no abnormality detected

Body weight:

Body weight gain was observed from d0 to d7.
1. experiment: 3 males: 494 g (d0), 598 g (d7); 3 females: 462 g (d0), 540 g (d7) --> BWG: +104/+78 g (m/f)
2. experiment: 3 males: 447 g (d0), 611 g (d7); 3 females: 518 g (d0), 539 g (d7) --> BWG: +164/+21 g (m/f)

Gross pathology:

no abnormality detected

Applicant's summary and conclusion

Conclusions:

In the inhalation hazard test no effects were detected in male and female rats after exposure for 8 h to saturated vapour (estimated concentration 2.19 mg/l) generated at 50°C.

Executive summary:

Study is comparable with the inhalation hazard test described in the Annex of OECD Guideline 403 (adopted 1981) with acceptable restrictions (post exposure observation period 7 days [but no symptoms]; no data about strain of test animals).

Rats were exposed for 8 h to saturated vapour generated at 50°C (liquid substance). The post exposure observation period was 7 days. The mortality rate was 0/6 in males and 0/6 in females. No clinical signs were observed during and after exposure. Necropsy revealed no treatment related effects.

Conclusion: In the inhalation hazard test no effects were detected in male and female rats after exposure for 8 h to saturated vapour (estimated concentration 2.19 mg/l) generated at 50°C.