Di-tert-pentyl peroxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: 1a: GLP, OECD Guideline 404

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Di-tert-pentyl peroxide

EC Number:

234-042-8

EC Name:

Di-tert-pentyl peroxide

Cas Number:

10508-09-5

Molecular formula:

C10H22O2

IUPAC Name:

2-methyl-2-[(2-methylbutan-2-yl)peroxy]butane

Test material form:

liquid

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Adult, New Zealand White rabbits were received at SLS from Myrtle's Rabbitry, Thompson Station, TN.
- Method of Identification: Upon receipt, plastic ear tags displaying unique identification numbers were used to individually identify the animals.
- Housing: The animals were housed individually in suspended stainless steel cages
-Food and water ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature : 71 °F
- Humidity (%): 48-67
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied : 0.5mL on a clipped area
- Concentration: undiluted

Duration of treatment / exposure:

4H

Observation period:

72H
Examination time points: 1h, 24 h, 48 h and 72 hours after the patch removal.

Number of animals:

6 males

Details on study design:

Preliminary Procedures: On day -1, the animals chosen for use on the primary skin irritation study had the fur removed from the dorsal area of the trunk using an animal clipper. Care was taken to avoid abrading the skin during the clipping procedure.

TEST SITE
- Area of exposure: flank - Details:
- % coverage:
- Type of wrap if used:


REMOVAL OF TEST SUBSTANCE
- Washing (if done): wiped with moistened cotton pad.
- Time after start of exposure: 4H


SCORING SYSTEM:
Irritation evaluated for each animal according to the grading scale originally proposed by Draize

Mortality checks were performed twice daily, in the morning and afternoon. lndividual body weights were obtained for each animal prior to dosing on study day O. Gross Necropsy: Each animal was euthanized (intravenous injection of sodium pentobarbital) following its final scoring interval. Gross necropsy examinations were not required for these animals

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal: mean

Remarks:

see attached file

Time point:

24/48/72 h

Score:

3.88

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: mean for the 6 rabbits (5 rabbits with mean erythema score of 4)

Results 2

Irritation parameter:

edema score

Basis:

animal: mean

Remarks:

see attached file

Time point:

24/48/72 h

Score:

1.15

Max. score:

2

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: mean for the 6 rabbits (4 rabbits with mean edema score of 1)

Irritant / corrosive response data:

Exposure to the test article produced very slight erythema on 1/6 test sites, mild to severe blanching on 5/6 test sites and very slight to slight edema on 6/6 test sites at the
1 hour scoring interval. The dermal irritation resolved completely in all animals by study
day 14. Additional dermal findings noted during the period included focal/pinpoint to moderate eschar, eschar exfoliation and desquamation, which were noted on 1/6, 1/6 and 6/6 test sites, respectively.

Any other information on results incl. tables

See individual results in the attached tables.

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

Under these experimental conditions, di-tert-amyl peroxide is considered as a skin irritant.

Executive summary:

The acute dermal irritation of di-tert-amyl peroxide was evaluated in rabbits according to a method similar to OECD 404 guideline. 0.5 ml of the substance was applied undiluted during 4 hours in 6 rabbits on intact or scarified skin (occlusive dressing). The cutaneous reaction was observed 24, 48 and 72 hours after removal of the dressing, and at day 7, 10 and 14.

Exposure to the test article produced very slight erythema on 1/6 test sites, mild to severe blanching on 5/6 test sites and very slight to slight edema on 6/6 test sites at the 1 hour scoring interval. The mean erythema score (over 24, 48 and 72 hours) was 3.88 and the mean edema score was 1.75 (over 24, 48 and 72 hours).The dermal irritation resolved completely in all animals by study

day 14. Additional dermal findings noted during the period included focal/pinpoint to moderate eschar, eschar exfoliation and desquamation, which were noted on 1/6, 1/6 and 6/6 test sites, respectively.

The mena erythema and edema scores over 24, 48 and 72 hours were respectively 3.88 and 1.15.

Under these experimental conditions, di-tert-amyl peroxide is considered as a skin irritant.