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Eye irritation

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Administrative data

Endpoint:
eye irritation: in vivo
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH


1. HYPOTHESIS FOR THE ANALOGUE APPROACH
Diarrylide pigments are inert substances that do not cause eye irritation. The high molecular weight ( > 620 g/mol), their high melting point (decomposition > 300°C) and their insolubility in water and octanol (<0.01 mg/L) render them inactive in the aquatic environment of the eye. This assessment focuses on two structurally related organic pigments. It should however be noted that none of the organic pigments registered so far under REACH are classified for eye irritation. This is consistent with the BfR eye irritation exclusion rule that a substance with a solubility of less 0.005 mg/L is not irritating. The pigments have no structural feature belonging to the BfR inclusion rules.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

Target
Pigment Orange 16
EC 229-388-1
CAS 6505-28-8
2,2'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]


Source 1
Pigment Yellow 14
EC 226-789-3
CAS 5468-75-7
2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis[N-(2-methylphenyl)-3-oxobutanamide]

Source 2
Pigment Yellow 83
EC 226-939-8
CAS 5567-15-7
2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis[N-(4-chloro-2,5-dimethoxyphenyl)-3-oxobutanamide]


The tested substances contain more than 80% % of pigment. (PY 14 containted > 95%, PY 83 > 80%). The target substance as tested in other tests had a purity of >94%. Pigment products containing intentionally added other substances need to be assessed as a formulation.

3. ANALOGUE APPROACH JUSTIFICATION
The target substance has methoxy substitutents on the core structure, whereas the close analogue PY 14 is chlorinated methylated. The higher molecular weight analogue is methoxylated and chlorinated. The substances are all insoluble, have a similar density and decompose prior to melting at temperatures above 300°C. Due to the insolubility, they are not surface active and do not influence the pH. They have no functional groups that can ionize or hydrolyse at physiological conditions in the eye. Both analogues have been tested for eye irritation in rabbits according to a procedure that differs from the current OECD testing guideline 405 in the shorter observation time of 7days. However, since at no observation time point there was any indication of an effect on iris, cornea or conjunctivae, the shorter observation period is not relevant.
The insolubility as an indicator for absence of an eye irritation potential (<1.5 ug/L for the target substance) has been included in the BfR eye irritation exclusion rules.
Considering that the similar pigments cause no irritation at all, it is acceptable to conclude that Pigment Orange 16 does not require a classification for eye irritation without further testing.


4. DATA MATRIX
It is referred to the attachement since it is not possible to enter a table in this field.
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
read-across source
Reference
Endpoint:
eye irritation: in vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Study period:
1974
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well-documented study report which meets basic scientific principles.
Qualifier:
according to guideline
Guideline:
other: described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO)
Deviations:
not specified
GLP compliance:
no
Species:
rabbit
Strain:
other: Russian breed
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied: 0.1 g
Duration of treatment / exposure:
No rinsing of eyes in group 1 (3 animals); rinsing of eyes 30 seconds after application in group 2 (3 animals)
Observation period (in vivo):
7 days
Number of animals or in vitro replicates:
6
Details on study design:
SCORING SYSTEM: on the basis of the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the AFDO (basically in accordance with OECD TG 405)
Irritation parameter:
cornea opacity score
Basis:
mean
Time point:
other: 24, 48, 72 h
Score:
0
Max. score:
4
Remarks on result:
other: group 1 + group 2
Irritation parameter:
iris score
Basis:
mean
Time point:
other: 24, 48, 72 h
Score:
0
Max. score:
2
Remarks on result:
other: group 1 + group 2
Irritation parameter:
conjunctivae score
Remarks:
( no differentiation between redness and chemosis)
Basis:
mean
Time point:
other: 24, 48, 72 h
Score:
0
Max. score:
3
Remarks on result:
other: group 1 + group 2
Irritant / corrosive response data:
No eye responses were noted in any animal at any time point.
Interpretation of results:
GHS criteria not met
Conclusions:
The test material is not irritating to eyes under these test conditions. This conclusion is legitimate as three animals (group 1) were tested basically in accordance with today's standard methods regarding dosing, exposure duration, scoring system, reading time points and no eye responses were noted in any animal at any time point.
Executive summary:

The test material was tested for eye irritancy according to a procedure described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO). 0.1 g neat test substance was applied to the conjunctival sac of one eye each of 6 animals (no washing in 3 animals, group 1, washing after 30 seconds in 3 animals, group 2) and eye responses were watched for seven days. No eye responses were noted in any animal at any time point. The test item is not irritating to eyes and has not to be classified as irritating to eyes according to the criteria of Regulation (EC) No 1272/2008.

Reason / purpose for cross-reference:
read-across source
Reference
Endpoint:
eye irritation: in vivo
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1972
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
other: described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO)
Deviations:
yes
Remarks:
7 day observation period (but absence of findings). Body weights not recorded.
GLP compliance:
no
Specific details on test material used for the study:
- Molecular formula: C36H32Cl4N6O8
- Substance type: powder
- Physical state: solid
- Analytical purity: >=80%
- Stability under test conditions: stable
Species:
rabbit
Strain:
other: English Silver
Details on test animals or tissues and environmental conditions:
TEST ANIMALS:
- Housing: individually
- Diet: NAFAG, Gossau SG, rabbit food, ad libitum
- Water: ad libitum
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied: 0.1 g
Duration of treatment / exposure:
No rinsing of eyes in 3 animals (group 1), rinsing after 30 seconds in other 3 animals (group 2)
Observation period (in vivo):
7 days
Number of animals or in vitro replicates:
6
Details on study design:
REMOVAL OF TEST SUBSTANCE
No rinsing of eyes in 3 animals (group 1), rinsing after 30 seconds in other 3 animals (group 2) with 10 ml lukewarm water

SCORING SYSTEM: "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics"
(19 59) of the US Association of Food and Drug Officials (AFDO), which uses the same grading as OECD TG 405.

TOOL USED TO ASSESS SCORE: slit lamp
Irritation parameter:
cornea opacity score
Basis:
mean
Time point:
other: 24, 48, 72 h
Score:
0
Max. score:
4
Remarks on result:
other: group 1 + group 2
Irritation parameter:
iris score
Basis:
mean
Time point:
other: 24, 48, 72 h
Score:
0
Max. score:
2
Remarks on result:
other: group 1 + group 2
Irritation parameter:
conjunctivae score
Basis:
animal: #1, #2 (group 1), #3, #4, #5 (group 2)
Time point:
other: 24, 48, 72 h
Score:
0
Max. score:
3
Remarks on result:
other: no differentiation between redness, chemosis, discharge
Irritant / corrosive response data:
No eye responses were observed except conjunctivae score 6 (incl. chemosis, discharge) in animal #3 (group 1) 24 h after application, fully reversible by 48 h after application.

         Rabbit #3 (group 1)
 Days after appl.  Cornea  Iris  Conjunctivae
 1  0  0  6
 2  0  0  0
 3  0  0  0
 4  0  0  0
 7  0  0  0

Conjunctivae = [Redness (max. score 3) + Chemosis (max. score 4) + Discharge (max. score 3)] x 2

The conjunctivae score for animal #3 one day after application is put together like (3 + 0 + 0) for redness score 3 or (0 + 3 + 0) for chemosis score 3 in the worst case. Discharge is not relevant for classification according to the criteria of Regulation (EC) No 1272/2008. Therefore, the maximum mean value for either conjunctival redness or chemosis over 24 h, 48 h and 72 h after application is 1, which falls below critical values for classification according to the criteria of Regulation (EC) No 1272/2008.

Interpretation of results:
GHS criteria not met
Conclusions:
According to the classification criteria of Regulation (EC) No 1272/2008 the test material is not irritating to eyes under these test conditions. This conclusion is legitimate as three animals (group 1) were tested basically in accordance with today's standard methods regarding dosing, exposure duration, scoring system, reading time points and the observed eye responses were fully reversible 48 hours after application.
Executive summary:

The test material was tested for eye irritancy according to the technique described in the "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959) of the US Association of Food and Drug Officials (AFDO). 0.1 g test substance was applied to the conjunctival sac of one eye each of 6 animals (no washing in 3 animals, group 1, washing after 30 seconds in other 3 animals, group 2) and eye responses were watched for seven days. No eye responses were observed except conjunctival score 6 (incl. redness, chemosis, discharge) in animal #3 (group 1) 24 h after application, fully reversible by 48 h after application. As the mean values of the observed eye responses fall below the critical values for classification according to the criteria of Regulation (EC) No 1272/2008, the test material is not irritating to eyes and has not to be classified for eye irritation.

Data source

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]
EC Number:
229-388-1
EC Name:
2,2'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]
Cas Number:
6505-28-8
Molecular formula:
C34H32N6O6
IUPAC Name:
2,2'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): C.I. Pigment Orange 16
- Physical state: orange coloured powder
- Storage condition of test material: approximately 4 °C in the dark

Test animals / tissue source

Species:
rabbit

Test system

Vehicle:
unchanged (no vehicle)

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
iris score
Basis:
mean
Time point:
24/48/72 h
Score:
ca. 0
Max. score:
2
Reversibility:
fully reversible
Remarks on result:
no indication of irritation
Irritation parameter:
cornea opacity score
Basis:
mean
Time point:
24/48/72 h
Score:
ca. 0
Max. score:
4
Reversibility:
fully reversible
Remarks on result:
no indication of irritation
Irritation parameter:
conjunctivae score
Basis:
mean
Time point:
24/48/72 h
Score:
ca. 0
Max. score:
4
Reversibility:
fully reversible
Remarks on result:
no indication of irritation
Irritation parameter:
chemosis score
Basis:
mean
Time point:
24/48/72 h
Score:
ca. 0
Max. score:
4
Reversibility:
fully reversible
Remarks on result:
no indication of irritation

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met