Reaction mass of 2,6-di-tert-butylphenol and 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:

From November 26, 1900 to December 11, 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: There are no deviations from the OECD Guideline 404 (Acute Dermal Irritation / Corrosion). No GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tri-tert-butylphenol; 2,6-di-tert-butylphenol

EC Number:

907-745-9

Molecular formula:

Not applicable - Multiconstituent substance

IUPAC Name:

2,4,6-tri-tert-butylphenol; 2,6-di-tert-butylphenol

Details on test material:

- Physical state: Clear pale yellow liquid on receipt, but solidified on storage at 0-5 ºC.
- Storage condition of test material: On its arrival the test substance was stored in the dark at ambient temperature. Following receipt of further information, the storage conditions were changed on 13th September 1990 to in the dark at between 0-5 ºC.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Froxfield Farms U.K. Ltd.
- Age at study initiation: 3.5 to 5.5 months
- Weight at study initiation: males: 3.74-4.01 kg; females: 3.55-4.10 kg
- Housing: Animals were singly housed in hanging, stainless steel cages with perforated dimple or wire-mesh flooring. Sawdust-filled undertrays for excreta were placed beneath each cage and changed twice weekly. Each cage measured 91 cm x 66 cm x 45 cm.
- Diet (e.g. ad libitum): Pelleted diet (Standard Rabbit Diet, S.Q.C. Special Diet Services Ltd. ), ad libitum.
- Water (e.g. ad libitum): From public supply, ad libitum.
- Acclimation period: two weeks.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 15-20 ºC.
- Humidity (%): Animal room humidity exceeded the target range of 30-70% for more than two consecutirve (four hourly) recordings on six days of the study. The raised humidity had no overt effect upon the health of the rabbits.
- Air changes (per hr): not documented.
- Photoperiod (hrs dark / hrs light): 12 hours day and 12 hours night.


IN-LIFE DATES: From November 26, 1900 to December 11, 1990

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 ml

Duration of treatment / exposure:

The undiluted test material (0.5 ml) was applied to the skin on a 6 cm2 lint patch, covered with gauze and held in place by a semi-occlusive elactic adhesive bandage. After a 4 hour exposure the dresssings were removed, the skin washed with water and dried.

Observation period:

After treatment, animals were examined for erythema, oedema and other lesions at 24, 48 and 72 hours.

Number of animals:

Six rabbits (3 per sex)

Details on study design:

SCORING SYSTEM:
Erythema and oedema were scored on a five point scale (Study report - Attachment A).

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

other: 24, 48 and 72 h

Score:

1.44

Reversibility:

fully reversible within: 14 days

Results 2

Irritation parameter:

edema score

Basis:

mean

Time point:

other: 24, 48 and 72 h

Score:

0.7

Reversibility:

fully reversible within: 14 days

Irritant / corrosive response data:

The 4-hour semi-occluded topical application of 0.5 ml undiluted test substance to the clipped skin of six New Zealand White rabbits caused inflammatory reactions not exceeding well-defined erythema and very slight oedema. Maximum intensity of reaction occurred within 24 hours of treatment. Partial resolution of inflammation was first apparent 7 days after treatment but was commonly associated with desquamation of the treated skin. All dermal test sites were overtly normal two weeks after application.

Any other information on results incl. tables

Table 7.3.1: Dermal irritation scores

	Erythema						Oedema
Animal No	1	2	3	4	5	6	1	2	3	4	5	6
after 24 h	2	2	1	1	2	1	1	1	0	1	1	0
after 48 h	2	1	1	2	2	1	1	1	0	1	1	0
after 72 h	2	1	1	2	1	1	1	1	0	1	1	0
Mean score 24 – 72 h	1.4						0.7

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

On the basis of reactions observed in this study and the criteria defined in Council Directive 67/548/EC and CLP Regulation, the test substance is not classified as irritant to skin.

Executive summary:

Six New Zealand White rabbits (3 per sex) were exposed via the dermal route to 0.5 mL of the test substance per animal. After a 4 hour exposure the dresssings were removed, the skin washed with water and dried. After treatment, animals were examined for erythema, oedema and other lesions at 24, 48 and 72 hours. On the basis of reactions observed in this study and the criteria defined in Council Directive 67/548/EC and CLP Regulation, the test substance is not classified as irritant to skin.