Reaction mass of Sodium, bis[3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulphonato(3-)]chromate(1-) and sodium [3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1Hpyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulphonato(3-)]hydroxychromate(1-)]

Endpoint summary

Description of key information

Skin sensitiser

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

From March 14 to April 08, 1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The test was conducted by means of Read Across approach. The reliability of the source study report is 1. Further information was attached at section 13

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

1992

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

A LLNA study has not been conducted because adequate data from guinea pig Maximisation test study are already available.

Species:

guinea pig

Strain:

other: Pirbright White Strain (Tif: DHP)

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: CIBA-GEIGY Limited, Animal Production, 4332 Stein / Switzerland
- Females (if applicable) nulliparous and non-pregnant: not specified
- Microbiological status of animals, when known:
- Age at study initiation:
- Weight at study initiation: between 335 to 418 g
- Housing: individually in Macrolon cages (Type 3)
- Diet (e.g. ad libitum): standard guinea pig pellets - NAFAG No. 845, Gossau SG ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period:
- Indication of any skin lesions:
- Randomisation: assigned to the different groups by means of random numbers generated by the random number generator, identified by individual ear tags

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C
- Humidity (%): 30 to 70%
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 hours light cycle day

Route:

intradermal and epicutaneous

Vehicle:

other: Physiological saline and Bacto Adjuvant, Complete, Freund

Concentration / amount:

5 % for Intradermal injection
50 % for epidermal application

Day(s)/duration:

day 0 for intradermal injection and 8 for epidermal applicxation

Route:

epicutaneous, occlusive

Vehicle:

physiological saline

Concentration / amount:

10 %

Day(s)/duration:

Day 22

No. of animals per dose:

5 male and 5 female in the test group
5 male in the control group

Details on study design:

RANGE FINDING TESTS:
Intradermal Induction
The concentration for the intradermal injections was selected on account of the solubility of the test article in standard vehicles and its local and systemic tolerability in a pretest.
The following concentration of test article has been used for intradermal injection:
5% in physiological saline (w/v).
Since 5% of test substance in physiological saline could be injected and was well tolerated, this concentration was used for the intradermal induction.
Epidermal Applications (induction and challenge)
The concentrations for the epidermal applications were selected on account of the primary irritation potential of the test article. The following concentrations have been examined on separate animals for the determination of the maximum subirritant concentration:
- 10, 20, 30, and 50% in physiological saline.
50% was the highest possible concentration of the test article in physiological saline.
Reactions were observed with 20, 30, and 50% in physiological saline


MAIN STUDY
A. INDUCTION EXPOSURE:
DAY 0: INDUCTION, intradermal injections
Three pairs of intradermal injections (0.1 ml per injection) were made simultaneously into the left and right side of the shaved neck of the test and control group animals.
Test group:
- adjuvant/saline mixture 1:1 (v/v)
- 5% FAT 21061/C in physiological saline (w/v)
- 5% FAT 21061/C in the adjuvant/saline mixture (w/v)
Control group:
- adjuvant/saline mixture 1:1 (v/v)
- adjuvant/saline mixture 1:1 (v/v)
- physiological saline
DAY 8: INDUCTION, epidermal application
In the test group the test substance was incorporated in physiological saline and applied on a filterpaper patch to the neck of the animals (patch 2x4 cm; approx. 0.4 g per patch; occluded administration for 48 hours).
The control group was treated with the vehicle only.
Test group:
- 50% FAT 21061/C in physiological saline
Control group:
- physiological saline only

B. CHALLENGE EXPOSURE: day 22
The test and control group animals were tested on one flank with the test substance in physiological saline and on the other flank with the vehicle alone (patch 2x2 cm; approx. 0.2 g per patch; occluded administration for 24 hours).
Test and control group:
- 10% FAT 21061/C in physiological saline
- physiological saline only

Positive control substance(s):

yes

Remarks:

2-mercaptobenzothiazole

Positive control results:

Test and results fullfill the requirements for reliability check of the OECD Guideline 406.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

10 %

No. with + reactions:

7

Total no. in group:

10

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10 %

No. with + reactions:

8

Total no. in group:

10

Observations and records

Induction reactions

After the intradermal and the epidermal induction application irritant reactions are normally induced by the adjuvant and the

high test article concentration. Because most of the reactions are treatment related and not compound related, the reactions

are only described in special cases in the section of results.

Challenge reactions

Twenty four and forty eight hours after removing the dressings, the challenge reactions were graded according to the Draize

scoring scale.

General

The body weight was recorded at start and end of the test.

Interpretation of results

The sensitising potential of the test susbtance was classified according to the grading of Magnusson and Kligman.

According to the guide to the labelling of dangerous substances and the criteria for the choice of sentences indicating particular hazards (R sentences) attributed to dangerous substances (Commission Directive 93/21/EEC, April 27, 1993) a test article was classified as a sensitiser in the case where a positive response was noted in at least 30 % of the animals.

Interpretation of results:

other: Category 1B (indication of skin sensitising potential) based on CLP criteria

Conclusions:

Skin sensitising

Executive summary:

Method

The test substance was evaluated for its skin sensitisation potential using the "Guinea Pig Maximisation test", as described in the OECD Guideline 406.

Results

Under the experimental conditions employed, 70 % and 80 % of the animals of the test group showed skin reactions 24 and 48 hours after removing the dressings, respectively.

Body weights were not affected by treatment.

Conclusion

The test substance for this test is considered as a skin sensitiser.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

SKIN SENSITIZATION

Category 1

Substances shall be classified as skin sensitizers in category 1 where data are not sufficient for sub-categorisation in accordance with the following criteria:

(a) if there is evidence in humans that the substance can lead to sensitisation by skin contact in a substantial number of persons; or

(b) if there are positive results from an appropriate animal test.

Specific criteria of animal test:

when an adjuvant type test method for skin sensitisation is used, a response of at least 30 % of the animals is considered as positive.

For a non-adjuvant Guinea pig test method a response of at least 15 % of the animals is considered positive.

Furthermore, stimulation index of three or more is considered a positive response in the local lymph node assay.

Sub-category 1A

Substances showing a high frequency of occurrence in humans and/or a high potency in animals can be presumed to have the potential to produce significant sensitisation in humans. Severity of reaction may also be considered.

Specific criteria:

Local lymph node assay-EC3 value ≤ 2 %

Guinea pig maximisation test-≥ 30 % responding at ≤ 0,1 % intradermal induction dose or ≥ 60 % responding at > 0,1 % to ≤ 1 % intradermal induction dose

Buehler assay - ≥ 15 % responding at ≤ 0,2 % topical induction dose or ≥ 60 % responding at > 0,2 % to ≤ 20 % topical induction dose

Sub-category 1B

Substances showing a low to moderate frequency of occurrence in humans and/or a low to moderate potency in animals can be presumed to have the potential to produce sensitisation in humans. Severity of reaction may also be considered.

Local lymph node assay - EC3 value > 2 %

Guinea pig maximisation test- ≥ 30 % to < 60 % responding at > 0,1 % to ≤ 1 % intradermal induction dose or ≥ 30 % responding at > 1 % intradermal induction dose.

Buehler assay - ≥ 15 % to < 60 % responding at > 0,2 % to ≤ 20 % topical induction dose or ≥ 15 % responding at > 20 % topical induction dose.

Based on animal test (Guinea pig maximisation test) results performed, according to the paragraph 3.4. of the CLP Regulation n. 1272/2008, the test substance is Classified in Sub category 1B,  as 8 animal were positive after treatment (intradermal dose = 5 % of test substance).