Methyloxirane

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:

other: Comparable to guideline study, predates GLP, available as unpublished report, minor limitations in reporting but otherwise adequate for assessment.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1977

Report date:

1977

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

no

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Methyloxirane

EC Number:

200-879-2

EC Name:

Methyloxirane

Cas Number:

75-56-9

Molecular formula:

C3H6O

IUPAC Name:

2-methyloxirane

Details on test material:

Propylene oxide ex SCUK, Carrington, Purity not specified in report

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Shell toxicology Laboratory (Tunstall)
- Age at study initiation: 10 to 13 weeks
- Housing: metal cages
- Diet: ad libitum
- Water: ad libitum

Food and water were denied to the animals only during exposure periods.

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

The test atmospheres were generated dynamically by nearly saturating part of the total air flow to the test chambers with propylene oxide vapour. This was accomplished by passing a controlled airflow through a wick-type saturator maintained at ) C in an ice/water bath with air stirring. The air/vapour mixture from the saturator was then blended with a controlled flow of clean air in a 2 litre mixing vessel. The generated atmosphere then passed from the mixing vessel into the test chambers.

The rats were housed in cylindrical glass exposure chambers consisting of 10 cm ID industrial glass pipe sections (QVF) 46 cm in lenght fitted with 10 to 2.5 cm reduction peaces at each end. The animals were placed in the tubes on metal carriers fabricated from 3 mm stainless steel rod. The upper surface of the carrier was divided into five compartments so that each pipe section housed five animals. The two test chambers were supplied from a common manifold made up of 2.5 cm ID glass pipe sections.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

3000, 3450, 4050, 4280, 4500, 5260, 5970 ppm

No. of animals per sex per dose:

4 animals per sex per dose

Control animals:

yes

Details on study design:

4 Male and 4 female rates were housed in two glassd exposure chambers supplied from a single atmospheric generator. Following the four h exposure period, the surviving animals were transferred to cages for a 14 d post-exposure observation period. At the end of this period the animals were killed.
Half hourly observations of the general health and behaviour of each animal were made. Pathological examination was not performed.

Statistics:

The organ weight were analysed using analysis of variance.

Results and discussion

Preliminary study:

Not applicable

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

4 197 ppm

Exp. duration:

4 h

Remarks on result:

other: 9.95 mg/L

Mortality:

See table below

Clinical signs:

other: Signs of toxicity appeared in all animals during the exposure period. These were excessive lachrymation and eye irritation followed by sedation, the development of respiratory difficaulty, piloerection and mucous discharge frequently bloodstained from the

Body weight:

No data

Gross pathology:

No data

Any other information on results incl. tables

Acute inhalation toxicity of propylene oxide in rats

Dosage ppm (v/v)	Cumulative mortality
	M	F	Total
3000	0/4	0/4	0/8
3450	0/4	0/4	0/8
4050	0/4	3/4	3/8
4280	2/4	2/4	4/8
4500	3/4	4/4	7/8
5260	4/4	4/4	8/8
5970	4/4	4/4	8/8