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Description of key information

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
Number of animals: 6; Exposure time: 24 h; Intact and abraded skin was exposed
GLP compliance:
no
Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
The rabbits were individually house in metal cages,
Room temperature: 19 °C
Relative humidity: 30-70 %
Air exchange: 19/h
Aritificial light: 12h in each 24 hour period
Preparation of test site:
other: abraded and intact skin
Vehicle:
water
Controls:
not required
Amount / concentration applied:
0,5 g amount of 2,2’-[azobis(1-methylethylidene)]bis[4,5-dihydro-1H-imidazole dihydrochloride, was applied under a 2.5 cm square gauze pad moist with 0,5mL distiiled water
Duration of treatment / exposure:
24 h
Observation period:
24 and 72 h
Number of animals:
6
Irritation parameter:
erythema score
Remarks:
Intact skin
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
fully reversible
Irritation parameter:
erythema score
Remarks:
Abraded skin
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
fully reversible
Irritation parameter:
edema score
Remarks:
Intact skin
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
fully reversible
Irritation parameter:
edema score
Remarks:
Abraded skin
Basis:
mean
Time point:
24/48/72 h
Score:
0
Max. score:
4
Reversibility:
fully reversible

Erythema and Eschar Formation

No erythema...................................................................................................................... 0

Very slight erythema (barely perceptible) ............................................................. ........... 1

Well defined erythema .................................................................................................... ...2

Moderate to severe erythema ...................................................................................... ...... 3

Severe erythema (beef redness) to eschar formation preventing grading of erythema..... ... 4

Maximum possible: 4

Oedema Formation No oedema ............................................................................................ 0

Very slight oedema (barely perceptible) ...................................................... ...... . 1

Slight oedema (edges of area well defined by definite raising) .............................. ............ 2

Moderate oedema (raised approximately 1 mm) 3

Severe oedema (raised more than 1 mm and extending beyond area of exposure) ......... ..... 4

Maximum possible: 4

Interpretation of results:
other: Based on "Appraisal of the Safety of Chemicals in Foods, Drugs, and Cosmetics", published by the Association of Food and Drug Officials of the United States, 1959, p. 46.
Conclusions:
2,2’-[azobis(1-methylethylidene)]bis[4,5-dihydro-1H-imidazole dihydrochloride is considered to be non - irritant to rabbit skin
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Referenceopen allclose all

Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)
GLP compliance:
yes (incl. certificate)
Species:
cattle
Strain:
not specified
Details on test animals or tissues and environmental conditions:
Isolated bovine cornea: The test system (target tissue) is the isolated bovine cornea. Bovine eyes are obtained as a by-product of freshly slaughtered cattle (age of the animals: minimum 12 months, maximum 60 months).
Vehicle:
other: De-ionized water
Controls:
yes, concurrent positive control
yes, concurrent negative control
Amount / concentration applied:
20% (w/v) solution in de-ionized water
Duration of treatment / exposure:
The corneas were incubated in a horizontal position at about 32 °C for approximately 4 hours (non-surfactant solids).
Number of animals or in vitro replicates:
Each treatment group (test substance, NC and PC) consisted of 3 corneas
Irritation parameter:
in vitro irritation score
Value:
2.6
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Interpretation of results:
GHS criteria not met
Remarks:
The IVIS score of the test substance of 2.6 would classify it as a substance that does not cause eye irritation or serious eye damage
Conclusions:
Applying the criteria of the OECD 437 for the assessment of the BCOP test results, the IVIS score of the test substance of 2.6 would classify it as a substance that does not cause eye irritation or serious eye damage. However, the Guideline also states, that due to limited accuracy of the BCOP test to correctly identify substances that do not require classification for eye irritation or serious eye damage, this test method should not be the first choice to initiate a bottom-up approach. Based on this statement test substances leading to IVIS <3 are generally examined in the EpiOcular test as well.
Endpoint:
eye irritation, other
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 405 (Acute Eye Irritation / Corrosion)
Qualifier:
according to
Guideline:
OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)
Version / remarks:
adopted 28. July 2015
GLP compliance:
yes (incl. certificate)
Species:
human
Details on test animals or tissues and environmental conditions:
The EpiOcularTM model (OCL-200) is a three-dimensional non-keratinized tissue construct composed of normal human derived epidermal keratinocytes used to model the human corneal epithelium. The EpiOcularTM tissues (surface 0.6 cm²) arecultured on especially prepared cell culture inserts and are
commercially available as kits (EpiOcular™ 200), containing 24 tissues on shipping agarose.
Vehicle:
other: The test substance is applied undiluted, therefore no preparation of the test substance in a vehicle was performed
Controls:
yes, concurrent positive control
yes, concurrent negative control
Amount / concentration applied:
A volume of 50 μL of the test material was applied covering the whole tissue surface.
Duration of treatment / exposure:
exposure time: 6 hours
Duration of post- treatment incubation (in vitro):
Postincubation period: 18 h
Number of animals or in vitro replicates:
3
Irritation parameter:
other: Optical density (wavelength 570 nm)
Value:
4
Negative controls validity:
valid
Remarks:
100
Positive controls validity:
valid
Remarks:
21
Interpretation of results:
Category 2 (irritating to eyes) based on GHS criteria
Conclusions:
In the current case, the EpiOcular test was positive and the test substance was assessed to be irritating.
Executive summary:

Applying the criteria of the OECD 437 for the assessment of the BCOP test results, the IVIS score of the test substance of 2.6 would classify it as a substance that does not cause eye irritation or serious eye damage. However, the Guideline also states, that due to limited accuracy of the BCOP test to correctly identify substances that do not require classification for eye irritation or serious eye damage, this test method should not be the first choice to initiate a bottom-up approach. Based on this statement and the experience of the test facility, test substances leading to IVIS < 3 are generally examined in the EpiOcular test as well. In the current case, the EpiOcular test was positive and the test substance was assessed to be irritating.

Based on the results for BCOP and EpiOcular Test and applying the evaluation criteria described in section 3.10, Azo Initiator VA044 shows an eye irritation potential in the in vitro eye irritation test strategy under the test conditions chosen.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Justification for classification or non-classification

Skin irritation/corrosion:

2,2’-[azobis(1-methylethylidene)]bis[4,5-dihydro-1H-imidazole dihydrochloride is considered to be non - irritant to rabbit skin

Eye irritation:

In the current case, the EpiOcular test was positive and the test substance was assessed to be eye irritating. Based on the findings the substance is considered to fulfil the criteria for classification of eye irritant category 2.