2,6-di-tert-butylphenol

Endpoint summary

Description of key information

Skin irritation / corrosion: PDII = 3.8 (OECD 404), Xi, R38

Eye irritation: maximum group mean score = 4.7 (OECD 405)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23/01/1991-06/02/1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD Guideline 404)

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: David Percival Ltd., Moston, sandbach, Cheshire, UK
- Age at study initiation: approximately twelve to sixteen weeks old
- Weight at study initiation: 2.08-2.74 kg
- Housing: The animals were individually housed in suspended metal cages
- Diet: ad libitum (Spillers Rabbit Diet, Dalfety Agriculture Ltd., Almondsbury, Bristol)
- Water: ad libitum, drinking water
- Acclimation period:minimum acclimatisation period of five days


ENVIRONMENTAL CONDITIONS
- Temperature: the animal room was maintained at 17-22°C
- Humidity: 49-61%
- Air changes: approximately 15 changes per hour
- Photoperiod: 12 hrs dark / 12 hrs light

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped

Vehicle:

water

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied:A quantity of 0.5 g of the test material, moistened with 0.5 ml of distilled water, was introduced under a 2.5 cm x 2.5 cm gauze patch and placed in position on the shorn skin.

Duration of treatment / exposure:

4 hours

Observation period:

1, 24, 48 and 72 hours. Additional observations were made on day 7 and 14 to assess the reversibility of the skin reactions.

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: 0.5 g of the test material, moistened with 0.5 ml of distilled water, 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 (BLENDERM: 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 (TUBIGRIP) and the animals were returned to their cages for the duration of the exposure period.


REMOVAL OF TEST SUBSTANCE
- Washing (if done): corset and patches were removed from each animal and any residual test material removed by gentle swabbing with cotton wool soaked in distilled water
- Time after start of exposure: four hours


SCORING SYSTEM: according to the scale from Draize J. H. (1959) Association of Food and Drug Officials of the United States, Austin, Texas, "The appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics"

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: 1, 24, 48, 72 hours

Score:

1 - 2

Max. score:

4

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: 7 days

Max. score:

4

Remarks on result:

other: 7 days: Adverse reactions prevented accurate evaluation of erythema. 9 days: animal killed

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: 1, 24, 48, 72 hours

Score:

2

Max. score:

4

Remarks on result:

other: Haemorrhage of the dermal capillaries. Light brown discolouration of the epidermis. Thickening of the skin. Loss of skin elasticity.

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: 7, 14 days

Score:

0

Max. score:

4

Reversibility:

other: reversible within 7 days

Remarks on result:

other: Crust formation after 7 d. Reduced fur re-growth after 14 days

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: 1, 24, 48, 72 hours

Score:

2

Max. score:

4

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: 7, 14 days

Score:

0

Max. score:

4

Reversibility:

other: reversible after 14 days

Remarks on result:

other: 7 days: adverse reactions prevented evaluation. 14 days: crust formation and reduced fur re-growth

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: 1, 24, 48, 72 hours

Score:

1

Max. score:

4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: 7 days

Max. score:

4

Remarks on result:

other: 7 days: adverse reactions prevented accurate evaluation of oedema. 9 days: animal killed

Irritation parameter:

edema score

Basis:

animal #2

Time point:

other: 1, 24, 48, 72 hours, 7 & 14 days

Score:

0 - 3

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

edema score

Basis:

animal #3

Time point:

other: 1, 24, 48, 72 hours, 7 & 14 days

Score:

0 - 3

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: 7 days: adverse reactions prevented accurate evaluation of oedema

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

other: S/6, S = Sum of 24 and 72 hour reading

Time point:

other: 24, 72 hours

Score:

3.8

Max. score:

8

Remarks on result:

other: moderate irritant

Irritation parameter:

erythema score

Basis:

mean

Time point:

other: 24, 48, 72 hours

Score:

2

Max. score:

4

Remarks on result:

other: positive criteria

Irritation parameter:

edema score

Basis:

mean

Time point:

other: 24, 48, 72 hours

Score:

1 - 2.3

Max. score:

4

Remarks on result:

other: positive criteria

Irritant / corrosive response data:

Very slight to well-defined erythema was noted at all treated skin sites one hour after patch removal, with well-defined erythema at all treated skin sites at the 24, 48, and 72-hours observations.

Very slight to moderate oedema was noted at all treated skin sites one and 24 hours after patch removal with very slight to slight oedema at the 48 and 72-hour observations.

Other effects:

Other adverse skin reactions noted at one treated skin site at this time were haemorrhage of dermal capillaries, light brown discolouration of the epidermis, thickening of the skin and loss of elasticity. Crust formation was noted at the 7 day observation. Hardened light brown-coloured scabs and thickening of the skin were noted at two treated skin sites at the 7 day observation. These reactions prevented accurate evaluation of erythema and oedema. Crust formation and/or reduced re-growth of fur was noted at two treated skin sites at the 14-day observation.

Key to tables:

Br = light brown discolouration of the epidermis

Cf = crust formation

Fr = reduced fur re-growth

Hd = haemorrhage of dermal capillaries

Le = loss of skin elasticity

Sp = hardened light brown-coloured scab

Th = thickening of the skin

?e = adverse reactions prevented accurate evaluation of erythema

?Od = adverse reactions prevented accurate evaluation of oedema

Individual skin reactions

Skin reaction	Observation time	Individual Scores – Rabbit Number and Sex (Bodyweight Kg)
		191 Female (2.08)	196Female (2.74)	204 Male (2.44)	Total
Erythema/eschar formation	1 h	1	2 Hd	2	(5)
	24 h	2	2 Hd	2	6
	48 h	2	2 Br	2	(6)
	72 h	2	2 BrThLe	2	6
	7 days	?eSpTh	0 Cf	?eSpTh	(0-8)
	14 days	-	0Fr	0CfFr	(0)
Oedema formation	1 h	1	3	3	(7)
	24 h	1	3	3	7
	48 h	1	2	2	(5)
	72 h	1	2	1	4
	7 days	?Od	0	?Od	(0-8)
	14 days	-	0	0	(0)
Sum of 24 and 72-Hour readings (S): 23
Primary Irritation Index (S/6): 23/6 = 3.8
Classification: Moderate irritant ( ) = total values not used for calculation of primary irritation index - = animal killed Individual daily and individual mean scores Skin reaction Reading (h) Individual Scores – Rabbit Number and Sex (Bodyweight Kg)   191 Female (2.08) 196 Female  (2.74) 204 Male (2.44)  Erythema/eschar formation  24 2 2 2   48 2 2 2   72 2 2 2   Total   6 6  6  Mean Score   2.0+ 2.0+ 2.0+   Oedema formation  24 1 3 3   48 1 2 2   72 1 2 1  Total   3 7 6  Mean Score   1.0 2.3+ 2.0+ + = positive criteria

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

The test material produced a primary irritation index of 3.8 and was classified as moderate irritant to rabbit skin according to the Draize Classification scheme. No corrosive effects were noted. The test material produced positive criteria in 3/3 rabbits according to the EEC labelling regulations and was classified as irritant to rabbit skin. The symbol "Xi" and risk phrase R38 "irritating to skin" are therefore required.

Executive summary:

A study was performed to assess the irritancy potential of the test material to the skin of the New Zealand White rabbit. The method used followed that described in the OECD Guidelines for Testing of Chemicals (1981) No. 404 "Acute Dermal Irritation/Corrosion" referenced as Method B4 in Commission Directive 84/449/EEC (which constitutes Annex V of Council Directive 67/548/EEC.

The results may be used as a basis for classification and labelling under Annex VI of Council Directive 67/548/EEC (as adapted to technical progress by Commission Directive 83/467/EEC).

A single 4 -hour, semi-occluded application of the test material to the intact skin of three rabbits produced well-defined erythema and very slight to moderate oedema. Other adverse skin reactions noted were haemorrhage of the dermal capillaries, light brown discolouration of the epidermis, thickening of the skin, loss of skin elasticity, crust formation, hardened light brown-coloured scab and reduced re-growth of fur.

The test material produced a primary irritation index of 3.8 and was classified as moderate irritant to rabbit skin according to the Draize Classification scheme. No corrosive effects were noted. The test material was also classified as irritant according to the EEC labelling regulations. The symbol "Xi" and risk phrase R38 "irritating to skin" are therefore required.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD 405)

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: David Percival Ltd., Moston, Sandbach, Cheshire, UK
- Age at study initiation: approximately twelve to sixteen weeks old
- Weight at study initiation: 2.64-3.14 kg
- Housing: The animals were individually housed in suspended metal cages
- Diet: ad libitum (Spillers Rabbit Diet, Dalgety Agriculture Ltd., Almondsbury, Bristol)
- Water: ad libitum, drinking water
- Acclimation period:minimum acclimatisation period of five days

Immediately before the start of the test, both eyes of the three provisionally selected test rabbits were examined for evidence of ocular irritation or defect with the aid of a light source from a standard ophthalmoscope. Animals showing evidence of ocular lesions were rejected and replaced.

ENVIRONMENTAL CONDITIONS
- Temperature: the animal room was maintained at 18-20°C
- Humidity: 49-61%
- Air changes: approximately 15 changes per hour
- Photoperiod: 12 hrs dark / 12 hrs light

Vehicle:

unchanged (no vehicle)

Controls:

other: The left eye remained untreated and was used for control purposes

Amount / concentration applied:

A volume of 0.1 ml of the test material, which was found to weigh approximately 67 mg (as measured by gently compacting the required volume into an adapted syringe

Duration of treatment / exposure:

1 second

Observation period (in vivo):

1, 24, 48 and 72 hours

Number of animals or in vitro replicates:

3

Details on study design:

The test material was placed into the conjunctival sac of the right eye, formed by gently pulling the lower lid away from the eyeball. The upper and lower eyelids were held together for about one second immediately after application, to prevent loss of the test material, and then released. Immediately after administration of the test material, an assessment of the initial pain reaction was made.

SCORING SYSTEM: Assessment of ocular damage/irritation was made according to the numerical evaluation given by Draize J. H. 1959, Association of Food and Drug Officials of the United states, Austin, Texas, "The Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics"

Any other adverse ocular effects were also noted.

TOOL USED TO ASSESS SCORE: Examination of the eye was facilitated by use of the light source from a standard ophthalmoscope

Irritation parameter:

cornea opacity score

Remarks:

E = degree of opacity

Basis:

animal: #1, #2, #3

Time point:

other: 1, 24, 48, 72 hours

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Remarks:

F = area of opacity

Basis:

animal: #1, #2, #3

Time point:

other: 1, 24, 48, 72 hours

Score:

0

Max. score:

4

Irritation parameter:

iris score

Basis:

animal: #1, #2, #3

Time point:

other: 1, 24, 48, 72 hours

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Remarks:

A = redness

Basis:

animal: #1, #2, #3

Time point:

other: 1, 24, 48, 72 hours

Score:

0 - 2

Max. score:

3

Reversibility:

fully reversible

Remarks:

2 animals: within 24 hours. 1 animal: within 48 hours

Irritation parameter:

chemosis score

Remarks:

B = Conjunctivae chemosis

Basis:

animal: #1, #2, #3

Time point:

other: 1, 24, 48, 72 h

Score:

0 - 1

Max. score:

4

Reversibility:

fully reversible within: 24 hours

Irritation parameter:

conjunctivae score

Remarks:

C = discharge

Basis:

animal: #1, #2, #3

Time point:

other: 1, 24, 48, 72 hours

Score:

0

Max. score:

3

Irritant / corrosive response data:

No adverse corneal or iridial effects were noted during the study.
Minimal conjunctival irritation was noted in all treated eyes one hour after treatment and in one treated eye at the 24-hour observation.
All treated eyes appeared normal 48 hours after treatment.

Individual total scores and group mean scores for ocular irritation

Rabbit number and sex	Individual total scores at:
	1 hr	24 hr	48 hr	72 hr
172 Female	4	0	0	0
193 Female	4	0	0	0
154 Male	6	2	0	0
Group total	14	2	0	0
Group mean score	4.7 1 hr	0.7 24 hr	0.0 48 hr	0.0 72 hr

Individual & mean scores for cornea, iris & conjunctivae required for EEC labelling regulations

Rabbit number and sex               (bodyweight Kg)	Time after treatment	Corneal opacity	Iridial inflammation	Conjunctival redness	Conjunctival chemosis
172 Female (3.14)	24 hr	0	0	0	0
	48 hr	0	0	0	0
	72 hr	0	0	0	0
Total		0	0	0	0
Mean		0.0	0.0	0.0	0.0
193 Female (2.64)	24 hr	0	0	0	0
	48 hr	0	0	0	0
	72 hr	0	0	0	0
Total		0	0	0	0
Mean		0.0	0.0	0.0	0.0
154 Male (2.84)	24 hr	0	0	1	0
	48 hr	0	0	0	0
	72 hr	0	0	0	0
Total		0	0	1	0
Mean		0.0	0.0	0.3	0.0

Interpretation of results:

GHS criteria not met

Conclusions:

The test material produced a maximum group mean score of 4.7 and was classified as a minimal irritant (class 3 on a 1 to 8 scale) to the rabbit eye according to a modified Kay and Calandra classification system.
The test material did not produced positive criteria in any rabbit according to the EEC labelling regulations and was classified as non-orritant to the rabbit eye. No symbol and risk phrase are therefore required.

Executive summary:

A study was performed to assess the irritancy potential of the test material, DTBH, to the eye of the New Zealand White rabbit. The method used followed that described in the OECD Guidelines for testing of Chemicals (1987) No. 405 "Acute Eye Irritation/Corrosion" referenced as Method B5 in Commission Directive 84/449/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

The results may be used as a basis for classification and labelling under Annex VI of Council Directive 67/548/EEC (as adapted to technical progress by Commission Directive 83/467/EEC).

A single application of the test material to the non-irrigated eye of three rabbits produced minimal conjunctival irritation. All treated eyes appeared normal 48 hours after treatment.

The test material produced a maximum group mean score of 4.7 and was classified as a minimal irritant (class 3 on a 1 to 8 scale) to the rabbit eye according to a modified Kay and Calandra classification system. The test material was also classified as non-irritant according to the EEC labelling regulations. No symbol and risk phrase are required.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation / corrosion:

Skin irritation / corrosion: The test material was evaluated for its irritancy potential to the skin of the New Zealand White rabbit. The test material produced a primary irritation index of 3.8 and was classified as moderate irritant to rabbit skin according to the Draize Classification scheme. No corrosive effects were noted. The test material was also classified as irritant according to the EEC labelling regulations. The symbol "Xi" and risk phrase R38 "irritating to skin" are therefore required.

Test method:

The method used followed that described in the OECD Guidelines for Testing of Chemicals (1981) No. 404 "Acute Dermal Irritation/Corrosion" referenced as Method B4 in Commission Directive 84/449/EEC (which constitutes Annex V of Council Directive 67/548/EEC.

The results may be used as a basis for classification and labelling under Annex VI of Council Directive 67/548/EEC (as adapted to technical progress by Commission Directive 83/467/EEC).

A single 4 -hour, semi-occluded application of the test material to the intact skin of three rabbits produced well-defined erythema and very slight to moderate oedema. Other adverse skin reactions noted were haemorrhage of the dermal capillaries, light brown discolouration of the epidermis, thickening of the skin, loss of skin elasticity, crust formation, hardened light brown-coloured scab and reduced re-growth of fur.

Eye irritation:

The test material was evaluated for its irritancy potential to the eye of the New Zealand White rabbit. The test material produced a maximum group mean score of 4.7 and was classified as a minimal irritant (class 3 on a 1 to 8 scale) to the rabbit eye according to a modified Kay and Calandra classification system. The test material was also classified as non-irritant according to the EEC labelling regulations. No symbol and risk phrase are required.

Test method:

The method used followed that described in the OECD Guidelines for testing of Chemicals (1987) No. 405 "Acute Eye Irritation/Corrosion" referenced as Method B5 in Commission Directive 84/449/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

The results may be used as a basis for classification and labelling under Annex VI of Council Directive 67/548/EEC (as adapted to technical progress by Commission Directive 83/467/EEC).

A single application of the test material to the non-irrigated eye of three rabbits produced minimal conjunctival irritation. All treated eyes appeared normal 48 hours after treatment.

Justification for classification or non-classification

Skin irritation / corrosion:

In accordance with EU CLP (Regulation (EC) No. 1272/2008) the test material was classified as irritant. A signal word 'Warning' and H-sentence H315 "Causes skin irritation" are therefore required.

Eye irritation:

In accordance with EU CLP (Regulation (EC) No. 1272/2008) the test material was classified as non-irritant. No symbol and risk phrase are required.