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Description of key information

Disperse Yellow 042 was found to be sensitising in a Guinea pig maximisation test (GPMT).

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
yes
Remarks:
(2 concentrations were applied on the same animal during first and rechallenge, skin sensitization study with the positive control was conducted within 7 months (instead of 6 months))
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
yes
Remarks:
(2 concentrations were applied on the same animal during first and rechallenge, skin sensitization study with the positive control was conducted within 7 months (instead of 6 months))
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Data from a reliable in vivo test conducted before the enforcement of Commission Regulation (EU) 640/2012 of 06 July 2012 amending, for the purpose of its adaptation to technical progress, Regulation (EC) No. 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 of the European Parliament and of the Council on the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) are available.
Specific details on test material used for the study:
Identification: Terasil Gelb GWL roh feucht laborgetrocknet (FAT 36014/F)
Description: Yellow to brown powder
EN/Batch Number: 292347.26
Purity/formulation: 90.7 % active ingredients
Stability of test article: Stable; expiration date: April 1998
Storage Conditions: At room temperature
Safety precautions: Gloves, goggle and face mask were obligatory to assure personnel health and safety.
Species:
guinea pig
Strain:
other: Ibm: GOHI; SPF-quality guinea pigs (synonym: Himalayan spotted)
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: BRL, Biological Research Laboratories Ltd., Wolferstrasse 4, CH-4414 Füllinsdorf/Switzerland
- Age at study initiation: Preliminary study- 6 to 8 weeks; Main study- 7 to 9 weeks
- Weight at study initiation: Preliminary study- 316 to 432 g; Main study- 301 to 426 g
- Housing: Individually in Makrol on type-3 cages (size: 22x37x15 cm) with standard softwood bedding ("Lignocel", Schill AG, CH-4132 Muttenz).
- Diet: Pelleted standard Kliba 342, Batch nos. 77/93 (from acclimatization start to July 20, 1993) and 78/93 (from July 21, 1993 to termination) guinea pig breeding/maintenance diet ("Kliba", Klingentalmühle AG, CH-4303 Kaiseraugst), ad libitum.
- Water: Community tap water from Fullinsdorf, ad libitum. Once weekly additional supply of ascorbic acid (1 g/L) via the drinking water.

ENVIRONMENTAL CONDITIONS
Air-conditioned with 10-15 air changes/h and continuously monitored environment with a temperature of 22 ± 3 °C, a relative humidity between 40-70 %, 12 h artificial fluorescent light (approx. 100 lux) /12 h dark, music during the light period.

IN-LIFE DATES: From July 19, 1993 to August 26, 1993
Route:
intradermal
Vehicle:
other: Acetone
Concentration / amount:
5%
Day(s)/duration:
0
Adequacy of induction:
highest technically applicable concentration used
Route:
epicutaneous, occlusive
Vehicle:
physiological saline
Concentration / amount:
25%
Day(s)/duration:
7 days
Adequacy of induction:
highest technically applicable concentration used
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: vaselinum album
Concentration / amount:
10% test substance - Posterior left flank
15% test substance - Anterior left flank
Day(s)/duration:
22
Adequacy of challenge:
highest non-irritant concentration
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
other: Vaselinum album
Concentration / amount:
10% test substance - Anterior left flank
15% test substance - Posterior left flank
Day(s)/duration:
36
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
Preliminary study: Intradermal injections group: 2 animals
Topical applications group: 4 animals

Main study:
Control group: 10 animals
Test group: 20 treated animals
Details on study design:
RANGE FINDING TESTS:
Intradermal injections: Intradermal injections (0.1 mL/site) were made into the clipped flank of two animals at concentrations of 5, 3 and 1 % of the test substance in acetone. The resulting dermal reactions were assessed 24 h later. For intradermal induction application a 5% test substance dilution was selected. Epidermal applications: Patches of filter paper (2 cm x 2 cm, held in place with occlusive dressing) were saturated with test substance at 25, 15, 10 and 5 % in vaselinum album and applied to the clipped and shaved flanks of 4 animals. The dressings were removed after an exposure period of 24 h and the depilated reaction sites were assessed 24 and 48 h after removal of the bandage for skin reactions using Draize scoring system.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: Topical induction: 48 h
- Test group:
Intradermal injection: On Day 1, 3 pairs (top, middle and down) of 5 % test substance in acetone were administered by intradermal injection in the clipped scapular region.
Topical induction: On Day 8, a filter paper (2 cm x 4 cm; held in place with occlusive dressing) was fully-loaded with 25 % test substance in vaselinum album), and then applied to the clipped and shaved scapular area (approx. 6 cm x 8 cm), over the intradermal injection sites for 48 h. The induction phase was followed by a 14 d rest period.
- Control group: Animals were treated as described above with the omission of test substance (acetone and vaselinum album only for intradermal and topical inductions respectively).
- Site: Scapular region
- Frequency of applications: Once intradermal, once topical
- Evaluations: Reaction sites were assessed for erythema and oedema 24 and 48 h after removal of the dressing using Draize scoring system.

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: First challenge: Day 22; Second challenge: Day 36
- Exposure period: 24 h
- First challenge: Test and control groups: On Day 22, three patches of filter paper ( 2 cm x 2 cm, held in place with occlusive dressing) were saturated with the 10 % (applied on the posterior left flank), 15 % (applied on the anterior left flank) of the test substance and the vehicle only (vaselinum album, applied to the right flank), using the same method as for the epidermal application. The dressings were removed after approx. 24 h.
- Second challenge: On Day 36, animals in the test group were treated in the same manner as that described for the first challenge except the applications were made to the opposite flanks of the animals. The control animals were treated with the vehicle alone on the left flank.
- Evaluation: Reaction sites were assessed for erythema and oedema 24 and 48 h after removal of the dressing using Draize scoring system.

OBSERVATIONS:
- Viability/mortality: Daily
- Clinical signs (local/systemic): Daily
- Skin reactions: At the times specified during the induction and challenge periods, scored in each animal according to the following scale:
Erythema and eschar formation:
No erythema.........................................................................................................................................0
Very slight erythema (barely perceptible).................................................................................................1
Well-defined erythema............................................................................................................................2
Moderate to severe erythema..................................................................................................................3
Severe erythema (beet redness) to slight eschar formation (injuries in depth)...............................................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 the area of exposure)....................................4

Any observations of edema or other lesions were recorded.
- Body weight: The body weight of each animal was recorded at the beginning of the acclimatization period, at Day one and at the termination of the test
- Necropsy: No necropsies performed except in one animal of the control group which was found dead on Day 18 of the treatment period.
Challenge controls:
First challenge: Test subsatnce (left flanks) and vehicle (right flank)
Second challenge: Vehicle (left flank)
Positive control substance(s):
yes
Remarks:
(2-mercaptobenzothiazole tested in another study)
Positive control results:
5/10 animals showed positive reactions (50%).
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
15 % epidermal application (anterior left flank)
No. with + reactions:
1
Total no. in group:
20
Clinical observations:
very slight erythematous reaction, grade 1
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. Hours after challenge: 24. Group: test group. Dose level: 15 % epidermal application (anterior left flank). No with. + reactions: 1. Total no. in groups: 20. Clinical observations: very slight erythematous reaction, grade 1.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10 % epidermal application (posterior left flank)
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no positive reactions
Remarks on result:
other: Reading: 1st reading. Hours after challenge: 24. Group: test group. Dose level: 10 % epidermal application (posterior left flank). No with. + reactions: 0. Total no. in groups: 20. Clinical observations: no positive reactions.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
15 % epidermal application (anterior left flank)
No. with + reactions:
3
Total no. in group:
20
Clinical observations:
very slight erythematous reaction, grade 1
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. Hours after challenge: 48. Group: test group. Dose level: 15 % epidermal application (anterior left flank). No with. + reactions: 3. Total no. in groups: 20. Clinical observations: very slight erythematous reaction, grade 1.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10 % epidermal application (posterior left flank)
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
no positive reactions
Remarks on result:
other: Reading: 2nd reading. Hours after challenge: 48. Group: test group. Dose level: 10 % epidermal application (posterior left flank). No with. + reactions: 0. Total no. in groups: 20. Clinical observations: no positive reactions.
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
15% epidermal application (anterior right flank)
No. with + reactions:
16
Total no. in group:
20
Clinical observations:
erythematous reactions, grade 1 to 3
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: 15% epidermal application (anterior right flank). No with. + reactions: 16.0. Total no. in groups: 20.0. Clinical observations: erythematous reactions, grade 1 to 3.
Reading:
rechallenge
Hours after challenge:
24
Group:
test chemical
Dose level:
10% epidermal application (posterior right flank)
No. with + reactions:
15
Total no. in group:
20
Clinical observations:
erythematous reactions, grade 1 to 3
Remarks on result:
other: see Remark
Remarks:
Reading: rechallenge. . Hours after challenge: 24.0. Group: test group. Dose level: 10% epidermal application (posterior right flank). No with. + reactions: 15.0. Total no. in groups: 20.0. Clinical observations: erythematous reactions, grade 1 to 3.
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
15% epidermal application (anterior right flank)
No. with + reactions:
17
Total no. in group:
20
Clinical observations:
erythematous reactions, grade 1 to 3
Remarks on result:
other: Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: 15% epidermal application (anterior right flank). No with. + reactions: 17.0. Total no. in groups: 20.0. Clinical observations: erythematous reactions, grade 1 to 3.
Reading:
rechallenge
Hours after challenge:
48
Group:
test chemical
Dose level:
10% epidermal application (posterior right flank)
No. with + reactions:
16
Total no. in group:
20
Clinical observations:
erythematous reactions, grade 1 to 3
Remarks on result:
other: see Remark
Remarks:
Reading: rechallenge. . Hours after challenge: 48.0. Group: test group. Dose level: 10% epidermal application (posterior right flank). No with. + reactions: 16.0. Total no. in groups: 20.0. Clinical observations: erythematous reactions, grade 1 to 3.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No erythema or oedema observed
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No erythema or Oedema was observed
Remarks on result:
no indication of skin sensitisation
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No erythema or edema
Remarks on result:
no indication of skin sensitisation
Reading:
rechallenge
Hours after challenge:
48
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No erythema or Edema
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
25%
No. with + reactions:
5
Total no. in group:
10
Clinical observations:
Erythema observed
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
25%
No. with + reactions:
5
Total no. in group:
10
Clinical observations:
Erythema observed
Remarks on result:
positive indication of skin sensitisation

Cutaneous reactions:

- In the preliminary test: At the 24 h reading of intradermal injection: A very slight erythema (grade 1) was noted at the injection sites of 2/2 animals.

- At both 24 and 48 h readings of epidermal application: Very slight erythema (grade 1) was noted at 15 % (1/4) and 25 % (3/4) concentrations of test substance.

- In the control group: The area around the intradermal injection sites were oedematous and erythematous from Day 2 to 4, and became necrotic from Day 5 to 12. Encrustation was observed from Day 13 to 17 and exfoliation of encrustation from Day 18 to 39 (termination of test).

- After first challenge in the control group, at the 24 and 48 h readings, no positive reactions were observed in the animals, neither when treated with vehicle alone (right flank) nor when treated with the test substance at 10 % (posterior left flank) and 15 % (anterior left flank). Similarly, after rechallenge in the control group, at the 24 and 48 h readings, no positive reactions were observed in the animals, when treated with vehicle alone (left flank).

- In the test substance treated group: the area around the intradermal injection sites was oedematous and erythematous from Day 2 to 4 (no erythema in second pair of injections), necrotic from Day 5 to 12/13 . Encrustation was observed from Day 13/14 to 17 and exfoliation of encrustation from Day 18 to 39 (termination of test).

- The cutaneous reactions observed after rechallenge on the right flank (test substance-treated) of the test substance treated group were of higher incidence and severity than those recorded on the left flank (vehicle treated) of the control group. Therefore, these findings were considered to be attributed to delayed contact hypersensitivity.

- Mortality: No unscheduled deaths occurred except one death in control group.

- Clinical signs (systemic): No symptoms of systemic toxicity were observed in the animals.

- Body weight: The body weight gain of the animals was not affected adversely during the study.

- Necropsy: One control animal was found dead on Day 18 of the treatment period. At necropsy, lungs, dark-red discoloured, were observed.

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
The test substance was considered to be sensitizing and is classified as Skin sensitizer.
Executive summary:

A guinea pig maximization study was conducted to evaluate the skin sensitization potential of the test substance (of 90.7% purity) according to OECD Guideline 406 and EU Method B.6 in compliance with GLP. Based on the results of a preliminary study, 5 and 25 % were selected as intradermal and topical induction concentrations, respectively. The highest non-irritating test substance concentration used for challenge application was 10 %. However, an additional test substance concentration of 15 % was applied in the challenge procedure because only one animal out of 4 showed a positive skin reaction during the epidermal pretest. A second challenge was performed two weeks after the first one. The treatment procedure was the same as adapted for the first challenge except that the applications were made to the opposite flanks of the guinea pigs. In the first challenge, 5 and 15 % of the animals showed erythematous reactions after the 24 and 48 h reading when treated with the test substance at 15 %. No reactions were noted at 10 %. In the second challenge, 80 % and 85 % of the animals showed erythematous reactions after the 24 and 48 h reading at 15 % and 75 % to 80 % of animals with the test substance at 10 %. Based on the observations of the study, the test substance was considered to be sensitizing and is classified as Skin sensitizer - 1B according to CLP Regulation.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

A guinea pig maximization study was conducted to evaluate the skin sensitization potential of the test substance (90.7 % purity) according to OECD Guideline 406 and EU Method B.6 in compliance with GLP. Based on the results of a preliminary study, 5 and 25 % were selected as intradermal and topical induction doses, respectively. The highest non-irritating test substance concentration used for challenge application was 10 %. However, an additional test substance concentration of 15 % was applied in the challenge procedure because only one animal out of 4 showed a positive skin reaction during the epidermal pretest. A second challenge was performed two weeks after the first one. The treatment procedure was the same as adapted for the first challenge except that the applications were made to the opposite flanks of the guinea pigs. In the first challenge, 5 and 15 % of the animals showed erythematous reactions after the 24 and 48 h reading when treated with the test substance at 15 %. No reactions were noted at 10 %. In the second challenge, 80 and 85 % of the animals showed erythematous reactions after the 24 and 48 h reading at 15 % and 75 to 80 % of animals with the test substance at 10 %. Based on the observations of the study, the test substance was considered to be sensitizing and is classified as Skin sensitizer - 1B according to CLP Regulation.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Disperse Yellow 042 was found to be sensitising in a Guinea pig maximisation test (GPMT) and warrants a classification as skin sensitiser 1B according to Regulation (EC) No. 1272/2008.