4-tert-butylbenzonitrile

Endpoint summary

Description of key information

4-tert-Butylbenzonitrile is practical non-toxic in primary skin and eye irritation tests according to OECD 404

("Acute dermal Irritation/Corrosion") and OECD 405 ("Acute Eye Irritation Study") )respectively, when applied at a concentration of 0.5 mL to the abraded and the intact skin or 0.1 mL instilled into the eyes of albino rabbits.

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:

january - march 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: J. Schitkovits, A-2620 Natschbach
- Weight at study initiation: animal No. 61: 3.3 kg; animal No. 62: 3.2 kg; animal No. 63: 2.7 kg.
- Housing: Individual caging in metal wire cages, Ehret GmbH, D-79312 Emmendingen, type KK 016R, 76 cm x 59 cm x 35 cm.
- Diet (e.g. ad libitum): Altromin 2023 diet for rabbits, ad libitum. Random samples of the feed are analysed for contaminats by Altromin, D-32791 Lage.
- Water (e.g. ad libitum): tap water from an automatical watering system, ad libitum.
- Acclimation period: 11 days
- Identification: Labelling with felt-tipped pen in a pinna.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): average of 20 °C
- Humidity (%): average of 55 %
- Air changes (per hr): 12 per hour
- Photoperiod (hrs dark / hrs light): artificial light from 6 a.m. to 6 p.m.

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

0.5 mL of the test substance

Duration of treatment / exposure:

4 hours

Observation period:

The treated areas and the surrounding untreated skin (control area) of the animals were examinated for erythema/eschar and oedema as well as for other local signs approximately 1, 24, 48 and 72 hours after patch removal. No examination were performed thereafter.

Number of animals:

3 females

Details on study design:

TEST SITE
- Area of exposure: dorsal area of the trunk
- coverage: about 2.5 cm x 2.5 cm
- Type of wrap if used: Samples of 0.5 mL of the test substance, were spread on cellulose patches (PurZellin-Tupfer, obtained by Fa. Hartmann, A-2355 Wiener Neudorf) were applied to the test sites. They were held in place by fixing them marginally with non irritating tapes ("Blenderm" surgical tape, hypoallergic, 3M, Medical Products Division, St. Paul, MN 551444, USA). The application sites were covered semi-occlusively by a dressing (Self adhesive non woven fabric, hypoallergenic, made by Beiersdorf AG, D-20245 Hamburg).

REMOVAL OF TEST SUBSTANCE
- Washing (if done): residual test substance was removed with wet Kleenex-tissues, if necessary.
- Time after start of exposure: 4 hours

SCORING SYSTEM:
Erythema/Eschar formation:
0 No erythema.
1 Very slight erythema (barely perceptible).
2* Well-defined erythema.
3* Moderate to severe erythema.
4* Severe erythema (beet redness) or eschar formation (injuries in depht).

Oedema formation:
0 No oedema
1 Very slight oedema (barely perceptible).
2* Slight oedema (edges of area are well defined by definite raising).
3* Moderate oedema (raised approximately 1mm).
4* Severe oedema (raised more than 1 mm and extending beyond area of exposure).

* may indicate irritation (R38), according to EC-Guideline 93/21.
irreversible lesions require R34, according to EC-Guideline 93/21.

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible

Irritation parameter:

edema score

Basis:

mean

Time point:

other: 24, 48 and 72 h after end of exposure

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: 1 h after end of exposure

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 24 h

Irritant / corrosive response data:

The treated skin of all three animals was scored for erythema and oedema. The test substance caused no adverse effects to the skin, except very
slight erythema in one animal 60 minutes after removal of the bandage. This effect was fully reversible within 24 h.

Other effects:

No general toxic effects were noted.

Table 1: Scores for the application sites. Individual data and means.

Time after the end of exposure	Erythema / Eschar			Oedema
	animal Nos			animal Nos.
	61	62	63	61	62	63
1 h	1	1	1	0	0	0
24 h	0	0	0	0	0	0
48 h	0	0	0	0	0	0
72 h	0	0	0	0	0	0
Mean (24-72 h)	0.0	0.0	0.0	0.0	0.0	0.0

Scoring system see section "details on study design".

Interpretation of results:

GHS criteria not met

Conclusions:

The treated skin of all three animals was scored for erythema and oedema. The test substance caused no adverse effects to the skin, except very
slight erythema in one animal 60 minutes after removal of the bandage. This effect was fully reversible within 24 h. This indicates that the test substance 4-tert-Butylbenzonitrile did not cause any skin irritation or corrosion in this study.

Executive summary:

The dermal irritation/corrosion potential of 4-tert-Butylbenzonitrile was examined in three female New Zealand White rabbits. Parts of there intact and shaved skin were exposed for 4 hours. The treated areas and the surrounding untreated skin (control area) of the animals were examined for erythema/eschar and oedema as well as for other local signs approximately 1, 24, 48, 72 hours after patch removal. Dermal irritation was described and recorded using a scoring system for erythema and oedema. The test substance caused no adverse effects to the skin, except very slight erythema in one animal 60 minutes after removal of the bandage. This effect was fully reversible within 24 h. This indicates that the test substance 4-tert-Butylbenzonitril did not cause any skin irritation or corrosion in this study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

january - march 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: J. Schitkovits, A-2620 Natschbach
- Weight at study initiation: animal No. 71: 3.0 kg; animal No.72: 2.5 kg; animal No.73: 3.5 kg.
- Housing: individual caging in metal wire cages, Ehret GmbH, D-79312 Emmendingen, type KK 016R, 79 com x 59 cm x 35 cm.
- Diet (e.g. ad libitum): Altromin 2023 diet for rabbits, ad libitum. Random samples of the feed are analysed for contaminats by Altromin, D-32791 Lage.
- Water (e.g. ad libitum): tap water from an automatical watering system, ad libitum.
- Acclimation period: 11 days (animal No. 71) and 17 days (animal No. 72 and No. 73).

ENVIRONMENTAL CONDITIONS
- Temperature (°C): average 20 °C
- Humidity (%): average of 59 %
- Air changes (per hr): 12 per hour
- Photoperiod (hrs dark / hrs light): artificial light from 6 a.m. to 6 p.m.

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 mL of 4-tert-Butylbenzonitrile
- Lot/batch no. (if required): FHI/TVT 281098
- Purity: > 94.2 %

Duration of treatment / exposure:

0.1 mL of the test substance was administered into the conjunctival sac of the right eye after gently pulling the lower lid away from the eyeball. After instillation, the eyes were held closed for about one second to prevent a loss of test substance.
The left eyes remained untreated and served as negative controls.

Observation period (in vivo):

Eye examination: 1, 24, 48 and 72 h after the administration (p. a.) of the test substance.

Number of animals or in vitro replicates:

three

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no

SCORING SYSTEM:
CORNEA:
Opacity: degree of density (area most dense area is taken for reading).
0 No ulceration or opacity.
1 Scattered or diffuse areas of opacity (except for slight dulling of normal lustre), details of iris clearly visible.
2 Easily discernible translucent area, details of iris slightly obscured.
3 Nacreous area, no details of iris visible, size of pupil barely discernible.
4 Opaque cornea, iris not discernible through the opacity.

IRIS:
0 Normal
1 Markedly deepened rugae, congestion, swelling, moderate circumcorneal hyperaemia or injection; any of these or combination of any thereof, iris still reacting to light (sluggish reaction is positive).
2 No reaction to light, haemorrhage, gross destruction (any of all these or all together).

CONJUNCTIVAE:
Redness: (refers to the most severe effect of palpebral and bulbar conjuctivae in comparison to the control eye).
0 Blood vessels normal.
1 Some blood vessels defintitely hyperaemic (injected).
2 Diffuse crimson colour, individual vessels not easily discernible.
3 Diffuse beefy red.

Chemosis: lids and/or nictating membranes.
0 No sweling.
1 Any swelling above normal (includes nictating membranes).
2 Obvious swelling with partial eversion of lids.
3 Swelling with lids about half closed.
4 Swelling with lids more than half closed.


TOOL USED TO ASSESS SCORE: an otoscope lamp

Irritation parameter:

cornea opacity score

Basis:

animal: # 71, 72 and 73

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

iris score

Basis:

animal: # 71, 72 and 73

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

other: redness

Basis:

animal: # 71

Time point:

other: 1, 24, 48 and 72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

other: redness

Basis:

animal: # 72 and 73

Time point:

other: 1 h

Score:

1

Max. score:

1

Reversibility:

fully reversible

Irritation parameter:

other: redness

Basis:

animal: # 71, 72 and 73

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

chemosis score

Basis:

animal: # 71

Time point:

other: 1 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritation parameter:

chemosis score

Basis:

animal: # 72 and 73

Time point:

other: 1 h

Score:

1

Max. score:

1

Reversibility:

fully reversible

Irritation parameter:

chemosis score

Basis:

animal: # 71, 72 and 73

Time point:

other: 24, 48, 72 h

Score:

0

Max. score:

0

Reversibility:

fully reversible

Irritant / corrosive response data:

Cornea, Iris: Only scores of "0", i.e. normal, were noted in all animals at all examination terms.
Conjunctivea, redness and chemosis: 2/3 animals were affected 1 h p.a., with a score of "1". No changes were observed later on.

Other effects:

No other effects were observed.

Table 1: Scores of the test eyes. Individual data and means.

Time after instillation (p.a.)	Cornea			Iris			Conjunctivae
							Redness			Chemosis
	animal No.			animal No.			animal No.			animal No.
	71	72	73	71	72	73	71	72	73	71	72	73
1 h	0	0	0	0	0	0	0	1	1	0	1	1
24 h	0	0	0	0	0	0	0	0	0	0	0	0
48 h	0	0	0	0	0	0	0	0	0	0	0	0
72 h	0	0	0	0	0	0	0	0	0	0	0	0
Mean (24-72 h)	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0	0.0

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the results of this test the test material 4-tert-Butylbenzonitrile is not considered to be an eye irritant.

Executive summary:

In an acute eye irritation study according to OECD Guideline 405, 0.1 mL of 4 -tert-Butylbenzonitrile was instilled into the right eye of three female albino rabbits (New Zealand White strain). The eyes were not washed afterwards and the left eyes remained untreated and served as negative controls. The animals then were observed 1, 24, 48 and 72 hours after the treatment. Irritation was scored and recorded by a scoring system concerning cornea, iris and conjunctivae.

Under the testing conditions cornea and iris were not affected in all of the test animals. Some injected blood vessels and a very slight swelling were observed in 2/3 animals 1 h p.a. Nevertheless this effect was fully reversible and no lesions were observed at the other examination terms. Therefore no classification for eye irritation of 4 -tert-Butylbenzonitrile is derived from the results of this study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

The dermal irritation/corrosion potential of 4-tert-Butylbenzonitrile was examined in three female New Zealand White rabbits. Parts of there intact and shaved skin were exposed for 4 hours. The treated areas and the surrounding untreated skin (control area) of the animals were examined for erythema/eschar and oedema as well as for other local signs approximately 1, 24, 48, 72 hours after patch removal. Dermal irritation was described and recorded using a scoring system for erythema and oedema. The test substance caused no adverse effects to the skin, except very slight erythema in the animals 60 minutes after removal of the bandage. This effect was fully reversible within 24 h. This indicates that the test substance 4 -tert-Butylbenzonitril did not cause any skin irritation or corrosion in this study.

In an acute eye irritation study according to OECD Guideline 405, 0.1 mL of 4 -tert-Butylbenzonitrile was instilled into the right eye of three female albino rabbits (New Zealand White strain). They eyes were not washed afterwards and the left eyes remained untreated and served as negative controls. The animals then were observed 1, 24, 48 and 72 hours after the treatment. Irritation was scored and recorded by a scoring system concerning cornea, iris and conjunctivae.

Under the testing conditions cornea and iris were not affected in all of the test animals. Some injected blood vessels and a very slight swelling were observed in 2/3 animals 1 h p.a. Nevertheless this effect was fully reversible and no lesions were observed at the other examination terms. Therefore no classification of 4 -tert-Butylbenzonitrile is derived from the results of this study.

 

Justification for classification or non-classification

No classification of 4-tert-Butylbenzonitrile as skin or eye irritating was derived from those two studies according to OECD 404 ("Acute dermal Irritation/Corrosion") and OECD 405 ("Acute Eye Irritation Study").