Hydrocarbons, C4, 1,3-butadiene- and isobutene-free

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non GLP, non-guideline, animal experimental study. Limitations in design and reporting but otherwise adequate for assessment.

Data source

Reference

Reference Type:

publication

Title:

Isobutane

Author:

Aviado DM, Zakheri S and Watanabe T

Year:

1977

Bibliographic source:

Non-Fluorinated Propellants and Solvents for Aerosols, chapter 6 pp 61-72. CRC Press, Cleveland, Ohio

Materials and methods

Test guideline

Qualifier:

no guideline available

Deviations:

not applicable

Remarks:

Pre-guideline study

Principles of method if other than guideline:

Groups of male mice were exposed to isobutane at various concentrations in air for 2 hours. Oxygen was added to prevent death from hypoxia.

GLP compliance:

no

Test type:

other: LC50

Test material

Test material information

Constituent 1

Reference substance name:

Isobutane

EC Number:

200-857-2

EC Name:

Isobutane

Cas Number:

75-28-5

Molecular formula:

C4H10

IUPAC Name:

isobutane

Details on test material:

- Name of test material (as cited in study report): Isobutane
- Substance type: A hydrocarbon
- Physical state: gas
- Composition of test material,

Test animals

Species:

mouse

Strain:

CF-1

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Wilmington, Massachusetts
- Weight: 20 to 25g

ENVIRONMENTAL CONDITIONS
- no data

IN-LIFE DATES
- no data

Administration / exposure

Route of administration:

inhalation: gas

Type of inhalation exposure:

whole body

Vehicle:

other: no data

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Glass chamber
- Exposure chamber volume: 10L
- Source and rate of air:The gaseous mixture was flushed into the chamber at a rate of 3L/min

Oxygen was added (25% of the volume of isobutane) to prevent death due to hypoxia

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

120 min

Concentrations:

36, 40, 50, 55, 55, 60 and 65 % v/v

No. of animals per sex per dose:

10 males

Control animals:

no

Details on study design:

- Duration of observation period following administration: none

Statistics:

An LC50 and 95% confidence limits were calculated by a probit method

Results and discussion

Effect levels

Effect levels 1

Sex:

male

Dose descriptor:

LC50

Effect level:

52.04 other: %

95% CL:

48.78 - 55.3

Exp. duration:

120 min

Remarks on result:

other: Regression coefficient 0.9662

Effect levels 2

Sex:

male

Dose descriptor:

LC50

Effect level:

520 400 ppm

Exp. duration:

120 min

Effect levels 3

Sex:

male

Dose descriptor:

LC50

Effect level:

1 237 mg/L air

Exp. duration:

120 min

Mortality:

Mortality was 0, 10, 30, 50, 90 and 100% at concentrations of 36, 40, 50, 55, 55, 60 and 65 % respectively.

Clinical signs:

other: Signs of central nervous system depression, rapid and shallow respiration, loss of posture and apnea were observed.

Body weight:

Not reported

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: other: EU (DSD)

Conclusions:

The 2-hour LC50 of isobutane was determined to be 52.04% v/v (approximately 520,400 ppm or 1237 mg/L).

Executive summary:

The authors examined lethality in male mice exposed for 2 hours to isobutane in air.

The LC₅₀was 52.04 +3.26 % v/v (approximately 520,400 ppm or 1237 mg/L) (MW 58.12)