sodium hydrogen [5-(diethylamino)-2-[(2-hydroxy-4-nitrophenyl)azo]phenolato(2-)][5-hydroxy-6-[(2-hydroxy-4-nitrophenyl)azo]-1-naphthalenesulfonato(3-)]-, chromate(2-)

Endpoint summary

Description of key information

Skin sensitising

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 August 22 to September 15, 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)

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

not specified

GLP compliance:

yes

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
- Weight at study initiation: between 334 to 405 g
- Housing: housed individually in Macrolon cages
- Diet: standard guinea pig pellets - NAFAG No. 845, Gossau SG ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 2 ± 3 °C
- Humidity (%): 30-70 %
- Photoperiod (hrs dark / hrs light): 12 hours light cycle day

Route:

intradermal and epicutaneous

Vehicle:

other: (Pretest) Intradermal/Epidermal: physiological saline; (Induction) Intradermal: physiological saline, Bacto Adjuvant, Complete, Freund and physiological saline ; Epidermal: physiological saline; (Challenge): physiological saline.

Concentration / amount:

5% (intradermal injection)
50% (epidermal application)
30% (challenge)

Route:

epicutaneous, occlusive

Vehicle:

other: (Pretest) Intradermal/Epidermal: physiological saline; (Induction) Intradermal: physiological saline, Bacto Adjuvant, Complete, Freund and physiological saline ; Epidermal: physiological saline; (Challenge): physiological saline.

Concentration / amount:

5% (intradermal injection)
50% (epidermal application)
30% (challenge)

No. of animals per dose:

20

Details on study design:

Pretests
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 the 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 of the test substance have been examined on separate animals for the determination of the maximum subirritant concentration:
20, 30, and 50% in physiological saline.
The undiluted test article was not applicable to the skin.
50% was the highest possible concentration of the test article in physiological saline.
Reactions were observed with 50% the test substance in physiological saline.

Test procedure
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% of the test substance in Physiological saline (w/v)
- 5% of the test substance 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% of test substance in physiological saline
Control group:
- physiological saline only
DAY 21: Challenge
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:
- 30% of test substance in physiological saline
- physiological saline only

Challenge controls:

Yes. The right flank was treated with the vehicle alone.

Positive control substance(s):

yes

Remarks:

mercaptobenzothiazole

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

30 %

No. with + reactions:

12

Total no. in group:

20

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

30 %

No. with + reactions:

8

Total no. in group:

20

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

Sensitising

Executive summary:

Method:

To assess the allergenic potential of the test substance in albino guinea pigs the Maximization-Test of B. Magnusson and A.M. Kligman (1969) was used. Ten animals were used as control group and 20 animals were used as test group as described in the OECD guideline 406.

 

Results:

The concentrations for the epidermal applications were selected on account of the primary irritation potential of the test article. The concentrations of the test article have been examined on separate animals for the determination of the maximum subirritant concentration. The concentration selected for the challenge was 30% in physiological saline.

 

Conclusion:

40% to 60% of the animals were positive after treatment with the 30% of test substance in physiological saline. Therefore the test article is considered to be a sensitizer.

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

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 on analog substance, according to the paragraph 3.4. of the CLP Regulation n. 1272/2008, the target substance is classified in Sub Category 1B,  as 40 % to 60 % of the animals were positive after treatment (intradermal dose = 5 % of test substance).