Trisodium bis[3-[(4,5-dihydro-3-methyl-5-oxo-1-phenyl-1H-pyrazol-4-yl)azo]-2-hydroxy-5-nitrobenzenesulphonato(3-)]chromate(3-)

Endpoint summary

Description of key information

Not 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:

August 17, 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:

no

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: 338 to 421 g
- Housing: the animals were housed individually in Macrolon cages (Type 3) , assigned to the different groups by means of random numbers generated by the random number generator, identified by individual ear tags,
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

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

Route:

intradermal and epicutaneous

Vehicle:

other: physiological saline

Concentration / amount:

Pretests
Intradermal Induction:
5% in physiological saline (w/v).
Epidermal Applications (induction and challenge):
50 % in physiological saline.

Route:

epicutaneous, occlusive

Vehicle:

other: physiological saline

Concentration / amount:

Pretests
Intradermal Induction:
5 % in physiological saline (w/v).
Epidermal Applications (induction and challenge):
50 % in physiological saline.

No. of animals per dose:

5 per sex for the test group and 5 of one sex for controls

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 of test substance have been examined on separate animals for the determination of the maximum sub irritant concentration :
30 and 50 % in physiological saline.
50 % was the highest possible concentration of the test article in physiological saline. The tested concentrations did not induce erythema reactions.

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 % in physiological saline (w/v)
- 5 % 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
The application site of all animals was pretreated with 10% sodium-laurylsulfate (open application) 24 hours prior to the epidermal induction application.
In the test group FAT 20043/D 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 20043/D in physiological saline
Control group:
- physiological saline only

B. CHALLENGE EXPOSURE
The test and control group animals were tested on one flank with FAT 20043/D 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:
- 50% FAT 20043/D in physiological saline
- physiological saline only

Challenge controls:

- physiological saline only

Positive control substance(s):

not specified

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50% in physiological saline

No. with + reactions:

1

Total no. in group:

20

Reading:

1st reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50% in physiological saline

No. with + reactions:

0

Total no. in group:

20

Number of positive animals per group after occlusive epidermal application:

Control Group		After 24 hours		After 48 hours
Vehicle control		0/10		0/10
Test control		0/10		0/10
Test Group		After 24 hours		After 48 hours
Vehicle control		0/10		0/10
Test control		1/10		0/10

Interpretation of results:

other: CLP criteria not met

Conclusions:

Not sensitising

Executive summary:

Method

The study was performed to determine the skin sensitisation potential of the test substance in rabbits according to OECD Guideline 406 (Skin Sensitisation).

Observations

Under the experimental conditions employed, 5 % of the animals of the test group showed skin reactions 24 hours after removing the dressings.

Conclusion

Not sensitising.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

No studies on the "Skin sensitisation" are available for the substance in itself nevertheless, a study was conducted with an analogue molecule (Similar Substance 01). Further information are reported in the Read Across justification attached to section 13.

The study was performed to determine the skin sensitisation potential of the test substance in rabbits according to OECD Guideline 406 (Skin Sensitisation). Under the experimental conditions employed, 5 % of the animals of the test group showed skin reactions 24 hours after removing the dressings.

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 not classified,  as only 1 animal was positive after treatment (intradermal dose = 5 % of test substance).