2,2'-dimethyl-2,2'-azodipropiononitrile

Endpoint summary

Description of key information

2,2'-AZOBIS(ISOBUTYRONITRILE) (AZDN) is considered as non-irritant to skin and eyes (guideline studies , OECD 404 and 405).

Skin irritaton :

In the skin irritation test (OECD 404), no cutaneous reactions were observed after a 4-hour exposure period to the skin of 3 rabbits. The mean of oedema score and erythema score was 0 (out of 4) at 24, 48 and 72 hours. The test substance is therefore considered as non-irritant to the skin.

 

Eye irritation :

AZDN is considered as non-irritant for the eye even though it did show very slight and transient ocular reactions when administered into the eyes of 3 rabbits (OECD 405). The mean scores calculated for 3 rabbits mean over 24, 48 and 72 hours were 0.3 for chemosis; 0.6 for redness of the conjunctiva; 0.1 for iris lesions, 0.3 for cornea (opacity) and 0.3 for corneal (area). All effects were fully reversible in 72 hours.

 

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:

3 July 1996 - 6 July 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute 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: Elevage cunicole de Val de Selle, 80160 Prouzel, FRANCE.
- Weight at study initiation: 2.7 +/- 0.1 kg
- Housing: Individually in polystyrene cages (35 cm x 55 cm x 32 cm or 48.2 cm x 58 cm x 36.5 cm)
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: At least five days before the beginning of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 +/- 3 °C
- Humidity (%): 30 to 70 %
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12h / 12h

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped

Vehicle:

unchanged (no vehicle)

Controls:

other: the untreated skin served as control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 500 mg

Duration of treatment / exposure:

4 hours

Observation period:

The skin was examined 1 hour, 24, 48 and 72 hours after removal of the dressing. If there were persistent cutaneous reactions after 72 hours, the observation was extended to a maximum of 14 days (until day 15) in order to determine the progress of the lesions and their reversibility.

Number of animals:

3 rabbits

Details on study design:

TEST SITE
- Area of exposure: 6 cm2
- Type of wrap if used: semi-occlusive


REMOVAL OF TEST SUBSTANCE
Any residual was wiped off by means of a dry gauze pad.

SCORING SYSTEM:
Dermal irritation was evaluated for each animal according to the grading scale as per OECD test guideline 404 (see below).

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

48 h

Score:

0

Max. score:

4

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

72 h

Score:

0

Max. score:

4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24 h

Score:

0

Max. score:

4

Irritation parameter:

edema score

Basis:

animal #2

Time point:

48 h

Score:

0

Max. score:

4

Irritation parameter:

edema score

Basis:

animal #3

Time point:

72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

No cutaneous reactions were observed during the study.

Interpretation of results:

not irritating

Remarks:

According to EU regulation (EC) No 1272/2008 (CLP)

Conclusions:

No cutaneous reactions were observed after a 4-hour exposure period onto the skin of 3 rabbits. According to the criteria laid down in Council Directive 67/548/EEC (and subsequent adaptations) on the approximation of laws, regulations and administrative provisions relative to the classification, packaging and labelling of dangerous substances, the test item is considered as non-irritant to the skin.

Executive summary:

The potential of the test item 2,2'-AZOBIS(ISOBUTYRONITRILE) to induce skin irritation was evaluated in rabbits according to OECD guideline 404. The study was conducted in compliance with the principles of the Good Laboratory Practice Regulations.

Methods:

The test item was applied for 4 hours to 3 New Zealand White rabbits. A single dose of 500 mg of the test substance was applied to the closely-clipped skin of the flank. The test substance was held in contact with the skin by means of a semi-occlusive dressing. Cutaneous reactions were observed approximately 1 hour, 24, 48 and 72 hours after removal of the dressing. The mean values of the scores for erythema and oedema were calculated for each animal.

Results:

No cutaneous reactions were observed during the study.

Conclusion:

 The test item 2,2' AZOBIS(ISOBUTYRONITRILE) is considered as non-irritant to the skin and is not classified.

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:

9 July 1996 - 12 July 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Elevage cunicole de Val de Selle, 80160 Prouzel, FRANCE
- Weight at study initiation: 2.8 +/- 0.1 kg
- Age at study initiation : no data
- Housing: no data
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least five days before the beginning of the study


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 +/- 3 °C
- Humidity (%): 30 -70 %
- Air changes (per hr): 12 cycles/hour
- Photoperiod (hrs dark / hrs light): 12h/12h

Vehicle:

unchanged (no vehicle)

Controls:

other: the right eye which remained untreated served as a control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 100 mg

Duration of treatment / exposure:

The lower and upper eyelids were held together for about one second to avoid any loss of test substance. The eyes were not rinsed after administration of the test substance.

Observation period (in vivo):

The eyes were examined approximately 1 hour, 24, 48 and 72 hours after administration of the test substance. If there was persistent ocular irritation after 72 hours, the observation period is extended to a maximum of 21 days (until day 22) in order to determine the progress of the lesions and their reversibility.

Number of animals or in vitro replicates:

Three rabbits

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): the eyes were not rinsed after administration of the test substance.

SCORING SYSTEM: Ocular irritation was evaluated for each animal according to the grading scale of OECD test guideline 405


TOOL USED TO ASSESS SCORE: To determine the presence or absence of corneal opacification, one or two drops of 0.5 % sodium fluorescein solution was instilled into the eye before the 24-hour reading.

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 24-72 hours

Irritation parameter:

conjunctivae score

Remarks:

(Redness)

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

0.6

Max. score:

3

Reversibility:

fully reversible within: 48-72 hours

Irritation parameter:

iris score

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

0.1

Max. score:

2

Reversibility:

fully reversible within: 48 hours

Remarks on result:

other: (1 animal)

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24, 48 and 72 hours

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 48-72 hours

Irritation parameter:

cornea opacity score

Remarks:

(area)

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 48-72 hours

Irritant / corrosive response data:

At the 1-hour reading, slight conjunctival reactions were observed in all animals: very slight or slight chemosis (grade 1 or 2) and very slight conjunctival redness (grade 1) were noted. These conjunctival reactions persisted up to day 2 (1 animal) and 3 (2 animals).
A very slight iritis (grade 1) was observed in one animal on day 1: it persisted for 24 hours.
At the 24-hour reading, a very slight corneal opacity (grade 1) was observed in two animals: it persisted for 24 hours in one of them.
The mean scores calculated for each animal over 24, 48 and 72 hours were 0.3, 0.0 and 1 for chemosis; 0.3, 0.7 and 0.7 for redness of the conjunctiva; 0.0, 0.0 and 0.3 for iris lesions and 0.3, 0.0 and 0.7 for corneal opacity.

Individual ocular examination and mean values of the scores recorded at each reading (24, 48 and 72 hours) for each animal :

Rabbit number	Region of eye	Description of ocular reactions	Scores				Mean irritation score
			1h D1	24h D2	48h D3	72h D4
01	Conjunctivae     Iris   Corneal opacity	- Chemosis - Redness       - Intensity	2 1   0   0	1 1   0   1	0 0   0   0	0 0   0   0	0.3 0.3   0   0.3
02	Conjunctivae     Iris   Corneal opacity	- Chemosis - Redness       - Intensity	1 1   0   0	0 1   0   0	0 1   0   0	0 0   0   0	0 0.7   0   0
03	Conjunctivae     Iris   Corneal opacity	- Chemosis - Redness       - Intensity	2 1   1   0	2 1   1   1	1 1   0   1	0 0   0   0	1 0.7   0.3   0.7

Interpretation of results:

slightly irritating

Remarks:

Migrated information (but not classified) Criteria used for interpretation of results: other: According to EU regulation (EC) No 1272/2008 (CLP) and EU Directive 67/584/EEC

Conclusions:

Very slight and transient ocular reactions were observed after administration of the test item into the eye of 3 rabbits. According to the criteria laid down in Council Directive 67/548/EEC, AZDN is considered as non-irritant for the eye.

Executive summary:

The potential of the test item 2,2'-AZOBIS(ISOBUTYRONITRILE) to induce eye irritation was evaluated in rabbits according to OECD guideline 405. The study was conducted in compliance with the principles of the Good Laboratory Practice Regulations.

Methods:

As no irritant effects were anticipated, a single dose of 100 mg of the test substance was introduced into the left conjunctival sac of three New Zealand White rabbits. The right eye served as a control. The test substance was used in its original form. The eyes were not rinsed after administration of the test substance.

The mean values of the scores recorded for each animal after 24, 48 and 72 hours were calculated.

Results:

At the 1-hour reading, slight conjunctival reactions were observed in all animals: very slight or slight chemosis (grade 1 or 2) and very slight conjunctival redness (grade 1) were noted. These conjunctival reactions persisted up to day 2 (1 animal) and 3 (2 animals).

A very slight iritis (grade 1) was observed in one animal on day 1: it persisted for 24 hours. At the 24-hour reading, a very slight corneal opacity (grade 1) was observed in two animals: it persisted for 24 hours in one of them.

The mean scores calculated for each animal over 24, 48 and 72 hours were 0.3, 0 and 1 for chemosis, 0.3, 0.7 and 0.7 for redness of the conjunctivae, 0, 0 and 0.3 for iris lesions and 0.3, 0 and 0.7 for corneal opacity.

Conclusions:

According to the criteria laid down in Council Directive 67/548/EEC (and subsequent adaptations), the test item 2,2'-AZOBIS(ISOBUTYRONITRILE) is considered as non-irritant for the eye and is not classified.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Justification for classification or non-classification

Skin and Eye irritation: the substance was unclassified according to the criteria laid down in  EU CLP No 2008/1272.