2,4,6-tri-tert-butylphenol

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 September 1992 to 26 September 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tri-tert-butylphenol

EC Number:

211-989-5

EC Name:

2,4,6-tri-tert-butylphenol

Cas Number:

732-26-3

Molecular formula:

C18H30O

IUPAC Name:

2,4,6-tri-tert-butylphenol

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Appearance: Dark yellow powder
- Storage conditions of test material: Room temperature

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: twelve to sixteen weeks
- Weight at study initiation: 2.31 to 2.73 kg
- Housing: The animals were individually housed in suspended metal cages.
- Diet: Free access to food
- Water: Free access to mains drinking water
- Acclimation period: a minimum of 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 18 to 21 °C
- Humidity: 56 to 58 % (relative)
- Air changes: approximately 15 changes per hour
- Photoperiod: lighting was controlled by a time switch to give continuous 12 hours of light and 12 hours of darkness.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

other: The test material was moistened with distilled water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.5 g

VEHICLE
- Amount applied: the test material was moistened with 0.5 mL of distilled water

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3 males

Details on study design:

TEST SITE
- Area of exposure: On the day before the test each of a group of three rabbits was clipped free of fur from the dorsal flank area using veterinary clippers. On the day of the test a suitable test site was selected on the back of each rabbit. The test material was introduced under a 2.5 x 2.5 cm gauze patch and placed in position on the shorn skin.
- Type of wrap if used: The patch was secured in position with a strip of surgical adhesive tape (approximate size 2.5 x 4.0 cm). To prevent the animals interfering with the patches, the trunk of each rabbit was wrapped in an elasticated corset.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Any residual test material was removed by gentle swabbing with cotton wool soaked in diethyl ether.
- Time after start of exposure: Four hours after application the corset and patches were removed from each animal.

SCORING SYSTEM: Approximately one hour following the removal of the patches, and 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored according to the Draize scale:

ERYTHEMA AND ESCHAR FORMATION
0 = No erythema
1 = Very slight erythema
2 = Well-defined erythema
3 = Moderate to severe erythema
4 = Severe erythema (beet redness) or eschar formation (injuries in depth)

OEDEMA FORMATION
0 = No oedema
1 = Very slight oedema (barely perceptible)
2 = Slight oedema (edges of area well-defined by definite raising)
3 = Moderate oedema (edges raised approximately 1 mm)
4 = Severe oedema (raised more than 1 mm and extending beyond the area of exposure)

Any other adverse skin reactions, if present, were also recorded.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

of all 3 animals

Time point:

other: Mean of the 24, 48 and 72 hour examinations

Score:

0.22

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Results 2

Irritation parameter:

edema score

Basis:

mean

Remarks:

of all 3 animals

Time point:

other: Mean of the 24, 48 and 72 hour examinations

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

The individual scores for erythema/eschar and oedema are given in Table 1.
Very slight erythema was noted at all treated skin sites one hour after patch removal and at one treated skin site at the 24 and 48-hour observations. Very slight oedema was noted at one treated skin site one hour after patch removal.
All treated skin sites appeared normal 72 hours after treatment.

Any other information on results incl. tables

Table 1: Individual Skin Reactions

Skin Reaction	Observation Time (hours)	Animal Number
		31	32	36
Erythema/Eschar Formation	1	1	1	1
	24	1	0	0
	48	1	0	0
	72	0	0	0
Oedema Formation	1	1	0	0
	24	0	0	0
	48	0	0	0
	72	0	0	0

 

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of this study the test material was determined to be non irritating to the skin.

Executive summary:

A study was performed to assess the irritancy potential of the test material in accordance with the standardised guidelines OECD 404 and EU Method B.4 under GLP conditions.

A single application of 0.5 g of the test material moistened with 0.5 mL of distilled water was made to the clipped skin of 3 male New Zealand White rabbits. The skin was exposed in a semi-occlusive fashion for a period of 4 hours.

Following the exposure period, any residual test material was removed by gentle swabbing with cotton wool soaked in diethyl ether. Approximately one hour following the removal of the patches, and 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored according to the Draize scale.

Very slight erythema was noted at all treated skin sites one hour after patch removal and at one treated skin site at the 24 and 48-hour observations. Very slight oedema was noted at one treated skin site one hour after patch removal.

All treated skin sites appeared normal 72 hours after treatment.

Under the conditions of this study the test material was determined to be non irritating to the skin.