Di-tert-butyl sec-butylidene diperoxide

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Start of the study: 9 May 1979 End of the study: 14 June 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1979

Report date:

1979

Materials and methods

Principles of method if other than guideline:

Trigonox D-B50 was dispersed to a fine mist by means of a stainless steel/glass aerodynamic nozzle nebulizer. The nebulizer was provided with a baffle in order to remove the larger droplets from
the mist produced. The mist was passed through the exposure chamber with a total airflow of 1.6 m^3/h for Trigonox D-B 50.

GLP compliance:

no

Test type:

traditional method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Di-tert-butyl sec-butylidene diperoxide

EC Number:

218-507-2

EC Name:

Di-tert-butyl sec-butylidene diperoxide

Cas Number:

2167-23-9

Molecular formula:

C12H26O4

IUPAC Name:

2,2-bis(tert-butylperoxy)butane

additive 1

Reference substance name:

Dibutyl phthalate

EC Number:

201-557-4

EC Name:

Dibutyl phthalate

Cas Number:

84-74-2

Molecular formula:

C16H22O4

IUPAC Name:

dibutyl phthalate

Constituent 2

Reference substance name:

Butanone

EC Number:

201-159-0

EC Name:

Butanone

Cas Number:

78-93-3

Molecular formula:

C4H8O

IUPAC Name:

butan-2-one

Test material form:

liquid

Specific details on test material used for the study:

Samples of the test materials were received from the principal on 9 April 1979. Trigonox D-B50 is also a clear, colourless liquid with the following composition:
49-51 % 2.2 -Di-tert-butylperoxy butane
51-49 % Dibutyl phthalate

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Fifty male and fifty female SPF-reared rats (Cpb; WU, Wistar Random) were obtained from the Central Institute for the Breeding of Laboratory Animals TNO, Zeist, The Netherlands. At the beginning of the study the mean body weight of the males was 180 g and that of the females 135 g.
During the 2-week observation period foll owing the exposure the animals were kept in stainless steel cages (5 to a cage), which were suspended in an open rack in an animal room. They received ad libitum the Institute's stock diet for rats and bottled unfluoridated water. However, during exposure the animals had no access to water and food.
The temperature and the relative humidity in the animal room were 21±1°C and 50 - 60 per cent respectively; they were automatically controlled.

Exposure chamber:
A stainless steel exposure chamber, having a capacity of 1.5 m^3 was used. The rats were kept individually during the exposure in wire-screen cages to prevent crowding and minimize filtration of inspired air by the animals' fur. They could be continuously observed through the hard glass entrance door of the chamber.

Administration / exposure

Route of administration:

inhalation: mist

Type of inhalation exposure:

not specified

Vehicle:

air

Details on inhalation exposure:

Trigonox D-B 50 was dispersed to a fine mist by means of a stainless steel/glass aerodynamic nozzle nebulizer. The nebulizer was provided with a baffle in order to remove the larger droplets from
the mist produced. The mist was passed through the exposure chamber with a total airflow of 1.6 m^3/h for Trigonox D-B 50.

Analytical verification of test atmosphere concentrations:

not specified

Duration of exposure:

4 h

Concentrations:

The maximum attainable concentration of the Trigonox D-B 50 aerosol in the test atmosphere turned out to be 2.42 g/m^3 air.

No. of animals per sex per dose:

5 animals per sex per dose.

Control animals:

no

Details on study design:

Analysis:
Analysis of the test atmosphere of Trigonox D-B 50 was performed gravimetrically. Samples of the atmosphere was taken by passing a measured quantity of the test atmosphere through a Cambridge glassfibre filter at intervals of about 1.5 hour. Particle size determinations and counts were carried out in samples taken from the atmosphere in the chamber with a Cascade Impactor.

Conduct of the study:
Five males and five females were exposed to the test material for 4 hours. After the exposure period the animals were returned to their living cages for an observation period of 2 weeks. During the 2-week observation period the body weight of the animals was frequently recorded.

Calculation of the LC50-values:
If applicable, the four-hour LC50 was calculated according to the method of Litchfield and Wilcoxon (1949).

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

2.42 other: g/m^3 air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No mortality occurred during the 4-hour exposure period and the subsequent observation period of 14 days.

Body weight:

The males and females gained weight in a normal way during the 14-day observation period.

Any other information on results incl. tables

The maximum attainable concentration of the Trigonox D-B 50 aerosol in the test atmosphere turned out to be 2.42 g/m³ air.

Droplet size determinations in impaction samples revealed a maximum droplet diameter of 6.7 μm. Ninety per cent of the mist consisted o.f droplets with a diameter of 1.2-3.3 μm.

No information on the behaviour of the rats during the exposure is available, because the animals were completely invisible as a consequence of the dense mist prevailing in the inhalation chamber. No mortality occurred during the 4-hour exposure period and the subsequent observation period of 14 days.

The males and females gained weight in a normal way during the 14-day observation period.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

From the results of the present acute inhalation toxicity studies it is concluded that:
the 4-hour LC50 of Trigonox D-B 50 in rats is higher than 2.42 g/m^3 air.

Executive summary:

1. The acute inhalation toxicity of curing agent, Trigonox D-B 50, was studied separately by exposing rats one single time for 4 hours to atmospheres containing aerosols

of each of the various substances.

2. Exposure to Trigonox D-B 50 at the maximum attainable concentration of 2.42 g/m³ air did not result in mortality or any sign of intoxication. It was concluded that the

4-hour LC₅₀ of Trigonox D-B 50 in rats was higher than 2.42 g/m³ air.