tert-butyl α,α-dimethylbenzyl peroxide

Endpoint summary

Description of key information

Skin irritation:

The acute dermal irritation of Peroximon 801 (96.8% tert-butyl cumyl peroxide) was evaluated in rabbits according to a GLP OECD 404 guideline (Manciaux, 1999b). The substance was applied undiluted to the skin of one New-Zealand White albino rabbit and held in contact for 3 minutes or 4 hours by means of a semi-occlusive dressing. As no irritation was observed after the 3 -minute exposure, the substance was applied to two other animals for 4 hours. Mean scores over 24, 48 and 72 hours for each animal were evaluated for erythema and for oedema. Animals were then observed daily until day 15. After a 4-hour exposure, no cutaneous reactions were observed in one animal. In the two other animals, a very slight or well-defined erythema was noted between days 1 and 6 and a slight oedema was recorded on days 2, 3 and 4. Dryness of the skin was observed in these animals from day 5 up to the end of the observation period (day 15). Mean scores over 24, 48 and 72 hours for each animal were 0.0, 2.0 and 2.0 for erythema and 0.0, 2.0 and 2.0 for oedema.

In conclusion, tert-butyl cumyl peroxide is mildly irritating to rabbit skin.

This conclusion is supported by the results of another study (TNO, 1978a), where the substance was topically applied for 24 hours to rabbit skin.

Eye irritation:

Trigonox T (90 -92% tert-butyl cumyl peroxide) was applied in eyes of 6 rabbits (0.1 mL) in a test conducted according to recognized standards (Draize method) (van Beek, 1978). The animals were observed 24 hours and 48 hours after the instillation. The scores for corneal opacity, iritis, conjunctival redness and chemosis were 0, 0, 0.1 and 0, respectively. Therefore the substance is not irritating to eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

17th July 1992

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Animals:
Sex, species, strain: male New Zealand White rabbits.
Reason for this choice: species generally accepted by regulatory authorities for this type of study. Breeder. Elevage Cunicole de Val de Selle, 80160 Prouzel, France.
Number of animals: three animals were used, as recommended by the international guidelines. Identification: the animals were identified individually with a metal ear tag.
Weight: on the day of treatment, the animals had a mean body weight ± standard deviation of
2.4±0.1 kg.
Acclimatization: at least 5 days before the beginning of the study.

Environmental conditions:
. temperature: 18 ± 3°C
. relative humidity: 30 to 70%
. light/dark cycle: 12 h/12 h
. ventilation: approximately 12 cycles/hour of filtered, non-recycled air.
The temperature and relative humidity were under continuous control and recording. The records were checked daily and filed. In addition to these daily checks, the housing conditions and corresponding instrumentation and equipment were verified and calibrated at regular intervals. The animals were housed individually in polystyrene cages (48.2 cm x 58 cm x 36.5 cm).
Each cage was equipped with a food container and a water bottle.

Food and water ad libitum

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

The test substance was used undiluted (0.5 ml)

Duration of treatment / exposure:

As possible irritant effects were anticipated, the test substance was evaluated in one animal in a first assay. The duration of exposure was 3 minutes on one flank and 4 hours on the other flank. Since the test substance was not strongly irritant in this first assay, it was then applied for
4 hours to two other animals in a second assay.

Observation period:

- 72 hours when there was no evidence of dermal irritation after 72 hours
- until day 15 when there was persistent cutaneous irritation after 72 hours

Number of animals:

3

Details on study design:

Doses of 0.5 ml of the test substance were placed on a 6 cm 2 dry gauze pad, which was then applied to the right flank (application for 4 hours) or the left flank (application for 3 minutes) of the animals. The test substance and the gauze pad were held in contact with the skin by means of an adhesive hypoallergenic aerated semi-occlusive dressing and a restraining bandage.

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 96h

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 96h

Irritant / corrosive response data:

After a 3-minute exposure (one animal): No cutaneous reactions were observed.
After a 4-hour exposure (three animals): No cutaneous reactions were observed in one animal.
In the two other animals, a very slight or well-defined erythema (grade 1 or 2) was noted between days 1 and 6 and a slight oedema (grade 2) was recorded on days 2, 3 and 4.
Dryness of the skin was observed in these animals from day 5 up to the end of the observation period (day 15).
Mean scores over 24, 48 and 72 hours for each animal were 0.0, 2.0 and 2.0 for erythema and
0.0, 2.0 and 2.0 for oedema. All the scores were 2 for animal 2 and 3, at 24, 48 and 72 hours

Other effects:

Any change in the animal behaviour was noted.

Interpretation of results:

Category 3 (mild irritant) based on GHS criteria

Conclusions:

t-BUTYL-CUMYL PEROXIDE is mildly irritating when applied topically to rabbits.

Executive summary:

The acute dermal irritation of Peroximon 801 (96.8 % tert-butyl cumyl peroxide) was evaluated in rabbits according to OECD 404 guideline (GLP study). The substance was applied undiluted to the skin of 1 New-Zealand White albino rabbit and held in contact for 3 minutes or 4 hours by means of a semi-occlusive dressing. As no irritation was observed after the 3-minute exposure, the substance was applied to two other animals for 4 hours. Mean scores over 24, 48 and 72 hours for each animal were evaluated for erythema and for oedema. Animals were then observed daily until day 15. After a 4-hour exposure (three animals): No cutaneous reactions were observed in one animal. In the two other animals, a very slight or well-defined erythema was noted between days 1 and 6 and a slight oedema was recorded on days 2, 3 and 4. Dryness of the skin was observed in these animals from day 5 up to the end of the observation period (day 15). Mean scores over 24, 48 and 72 hours for each animal were 0.0, 2.0 and 2.0 for erythema and 0.0, 2.0 and 2.0 for oedema.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro skin irritation study does not need to be conducted because adequate data from an in vivo skin irritation study are available

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

Draize method

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

The anirnals are caged individually and reccive no hay or ether extraneous material that might enter the eyes.

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

0.1 mL

Duration of treatment / exposure:

The eye has not been rinsed.

Observation period (in vivo):

The eyes were observed 24 hours, 48 hours, 72 hours and 7 days after instillation of the susbtance

Number of animals or in vitro replicates:

6

Details on study design:

The upper and lower eye lid are then carefully closed and subsequently held together for at least one second before releasing, to prevent loss of material Scoring with Draize method

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24/48 h

Score:

0.1

Max. score:

3

Reversibility:

fully reversible within: 48h

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

NOTE: Explanation for the concise "BASIS": Six rabbits were tested. ALL animals gave 0 (zero) scores for corneal opacity, iris, conjunctivae, and chemosis after 24 hours and after 48 hours, EXCEPT animal # 1 that had conjunctiva score of 1 after 24 hours only. Therefore individual scores are not entered for each animal for each parameter, and at each time point.

Interpretation of results:

GHS criteria not met

Conclusions:

Tert-butyl cumyl peroxide is not irritating to eyes.

Executive summary:

Trigonox T (90 -92% tert-butyl cumyl peroxide) was applied in eyes of 6 rabbits (0.1 mL) in a test conducted according to recognized standards (Draize method). The animals were observed 24 hours and 48 hours after the instillation. The scores for corneal opacity, iritis, conjunctival redness and chemosis were 0, 0, 0.1 and 0, respectively. Therefore the substance is not irritating to eyes.

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro eye irritation study does not need to be conducted because adequate data from an in vivo eye irritation study are available

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The substance is borderline (GHS cat 3) for skin irritation classification. Therefore, the current regulatory classification (cat 2, H315) is not challenged.

According to EU Regulation (EC) N0. 1272/2008 (CLP), the substance (TBCP) is not classified for eye irritation.