N,N'-(2-chloro-1,4-phenylene)bis[4-[(4-chloro-2-nitrophenyl)azo]-3-hydroxynaphthalene-2-carboxamide]

Endpoint summary

Description of key information

The pigment was found to be non irritating to rabbit skin and eyes.

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

occlusive dressing, 24 hours exposure duration, only 24- and 72-hour scoring available, 72-hour observation period

GLP compliance:

no

Specific details on test material used for the study:

- Physical state: brown powder

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Porton strain bred on the premises
- Age at study initiation: 3-4 months
- Weight at study initiation: ca. 2.23 kg for males and 2.55 kg for females
- Housing: caged singly in an experimental room
- Diet (e.g. ad libitum): commercial irradiated diet (Styles-Oxoid); ad libitum
- Water (e.g. ad libitum): sterile filtered drinking water; ad libitum
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 1°C
- Humidity (%): 50-70%
- Photoperiod (hrs dark / hrs light): 10/14

Type of coverage:

occlusive

Preparation of test site:

other: shaved or abraded (only data from the shaved skin sites are presented here, since they are suitable for assessment)

Vehicle:

other: 50% aqueous solution of polyethylene glycol

Controls:

other: untreated skin sites of the same animals

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g
- Concentration (if solution): 10 g of the test compound was mixed with 20 ml of a 50% aqueous solution of polyethylene glycol to make a solution of 25ml, 1.25ml of which was applied to each test site.

Duration of treatment / exposure:

24 hours

Observation period:

72 hours

Number of animals:

6 (3 males and 3 females)

Details on study design:

TEST SITE
- Area of exposure: at least 10% of the total body surface (the whole back) was shaved 24 hours before treatment). The shaven skin on the rightt side was slightly scarified immediately before treatment. The abrasions were sufficiently deep to penetrate the stratum corneum but not to damage the dermis. The left hand site remained intact.
- % coverage: a 2.5 cm square gauze pad was used
- Type of wrap if used: the pad was covered with aluminium foil secured with Sleek adhesive tape. The test sites were then enclosed by a 6" wide Coban self adhesive bandage, the edges of which were fixed to the skin by strips of Sleek in order to retain the test substance in close contact with the skin.

REMOVAL OF TEST SUBSTANCE
- Time after start of exposure: the gauze patches were removed 24 hours after the application

SCORING SYSTEM: comparable to the OECD scoring system (only 24- and 72-hour scores were determined)

Irritation parameter:

erythema score

Basis:

mean

Remarks:

Mean of all tested animals

Time point:

other: 24-72-hours

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

other: 48-hour scoring not performed

Irritation parameter:

edema score

Basis:

mean

Remarks:

Mean of all tested animals

Time point:

other: 24-72-hours

Score:

0.5

Max. score:

4

Reversibility:

fully reversible within: 72 hours

Remarks on result:

other: 48-hour scoring not performed

Irritant / corrosive response data:

No erythema formation was observed, neither on intact skin sites nor on the abraded ones. Edema was observed in all but one animals after 24 hours on intact skin sites (one animal with edema score 2 and 4 animals each with edema score 1), and in 4/6 animals at abraded skin sites (one animal with edama score 2 and 3 animals each with edema score 1). The edema formation was completely reversible within 72 hours. It could therefore be assumed that the test substance is not irritating according to EU-CLP.

Interpretation of results:

GHS criteria not met

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

7-day observation period

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Porton strain bred on the premises
- Age at study initiation: 10-12 weeks
- Weight at study initiation: ca. 2.23 kg for males and 2.55 kg for females
- Housing: caged singly in an experimental room
- Diet (e.g. ad libitum): commercial irradiated diet (Styles-Oxoid); ad libitum
- Water (e.g. ad libitum): sterile filtered drinking water; ad libitum
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 1°C
- Humidity (%): 50-70%
- Photoperiod (hrs dark / hrs light): 10/14

Vehicle:

unchanged (no vehicle)

Controls:

other: untreated eye of the same animal

Amount / concentration applied:

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

Duration of treatment / exposure:

continuously (3 animals without rinsing) or 30 second (3 animals with rinsing)

Observation period (in vivo):

up to 7 days

Number of animals or in vitro replicates:

3 without rinsing and 3 with rinsing

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): the treated eyes of 3 rabbits were each rinsed with 10 ml lukewarm water for 1 min (only the rabbits without washing are further considered for assessment, because they are closer to the guideline conditions)
- Time after start of exposure: about 30 seconds after treatment

SCORING SYSTEM: comparable to the OECD scoring system after 1, 6, 24, 48, and 72 hours, and after 7 days.

TOOL USED TO ASSESS SCORE: hand-slit lamp

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

other: 24-48-72-hours

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

iris score

Basis:

mean

Time point:

other: 24-48-72-hours

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

mean

Time point:

other: 24-48-72-hours

Score:

0.11

Max. score:

3

Reversibility:

fully reversible within: 48 hours

Remarks on result:

other: redness score of 1 was observed in one animal after 24 hours, but was completely reversible within 48 hours

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: 24-48-72-hours

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

Only chemosis (in all 3 animals without washing; scores 2, 2 and 1, respectively after 1 hours) and conjunctivae redness (in 2/3 animals after 1 hour [scores, each 1]; in 3/3 animals after 6 hours [1, 2 and 1 respectively]; and in 1/3 animals after 24 hours [1]) were observed, but were fully reversible within 6 and 48 hours, respectively. It therefore can be assumed that the test substance is not irritating to the rabbit eye.

Interpretation of results:

GHS criteria not met

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Pigment Brown 23 (CAS 35869-64-8, 850 g/mol)

 Pigment Brown 23 was tested in two valid studies in rabbits (Ciba-Geigy Ltd 1975) that were performed prior to the introduction in GLP. The eye irritation study followed procedures similar to OECD guideline 405. The observation was stopped after 7 days. A redness score of 1 was observed in one animal after 24 hours, but was completely reversible within 48 hours. Cornea and iris were not affected.

The skin irritation procedure involved 24h exposure with occlusive wrapping and a three-day observation period. The duration is longer than required by the OECD guideline 404, but the observation period is shorter. The study was performed prior to the introduction of GLP, but was reported with sufficient detail for evaluation. No erythema formation was observed, neither on intact skin sites nor on the abraded ones. Edema was observed in all but one animals after 24 hours on intact skin sites (one animal with edema score 2 and 4 animals each with edema score 1), and in 4/6 animals at abraded skin sites (one animal with edema score 2 and 3 animals each with edema score 1). The edema formation was completely reversible within 72 hours. Pigment Brown 23 is not irritating to skin and eyes.

 

Findings are consistent with application of the BfR skin and eye irritation rules. It shows that for all pigments, the inclusion rule as an eye irritant are not met and that several rules for exclusion are met (eg molecular weight > 650 Da, MP > 200°C, water solubility < 4 mg/L). As for skin irritation, again several exclusion rules are met. The alert “phenols” is identified, which is a false alarm, as it is included in the inert cromophore and present in all non-irritating pigments.

 

The materials used for testing in 1975 were not characterized for particles of the nano-size range.

 

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for skin or eye irritation under Regulation (EC) No. 1272/2008, as amended for the thirteenth time in Regulation (EC) No. 2018/1480.

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