Sodium 3-[[3-methoxy-4-[(4-methoxyphenyl)azo]phenyl]azo]benzenesulphonate

Endpoint summary

Description of key information

The test substance is a non-sensitizer.

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:

Experiment start date - 30 May 1994; Experiment end date - 30 June 1994; Study completion date - 23 September 1994.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes

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: Tectilon Gelb 4R roh, feucht , laborgetrocknet (FAT 20004/I)
Description: red-orange powder
Batch-Number: P 3+4 PM
Purity / Formulation: approx. 90 %
Expiration date - 09/98
Storage Conditions: at room temperature (approx. 20 °C)
Safety precautions: Gloves, goggles and face mask were obligatory to ensure personnel health and safety.

Species:

guinea pig

Strain:

other: Ibm: GOHI; SPF-quality guinea pigs

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: BRL, Biological Research Laboratories Ltd. Wölferstrasse 4, 4414 Füllinsdorf/Switzerland
- Age at study initiation: 5 - 7 weeks
- Weight at study initiation: 304-429 g
- Housing: Individually in Makrol on type-3 cages with autoclaved standard softwood bedding ("Lignocel", Schill AG, CH-4132 Muttenz).
- Diet: Pelleted standard Kliba 342, Batch no. 62/94 (at delivery of the animals to 02-JUN-1994) and 63/94 (from 03-JUN-1994 to termination of test) guinea pig breeding/ maintenance diet ("Kliba", Klingentalmühle AG, CH-4303 Kaiseraugst), ad libitum.
- Water: Community tap water from Füllinsdorf, ad libitum. Once weekly additional supply of ascorbic acid (1 g/l) via the drinking water.
- Acclimation period: One week for the control and test group under test conditions after health examination. No acclimatization for the animals of the pretest only animals without any visual signs of illness were used for the study.


ENVIRONMENTAL CONDITIONS
- Temperature: 22 - 25°C
- Humidity: 56 - 82 %,
- Photoperiod: 12 hours artificial fluorescent light (approx. 100 Lux) /12 hours dark, music during the light period.

IN-LIFE DATES: 06- to 30-JUN-1994

Route:

intradermal

Vehicle:

water

Concentration / amount:

5%

Day(s)/duration:

Day 1

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Route:

epicutaneous, open

Vehicle:

other: vaselinum album

Concentration / amount:

50%

Day(s)/duration:

Day 8

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

No.:

#1

Route:

epicutaneous, open

Vehicle:

other: vaselinum album

Concentration / amount:

25 %

Day(s)/duration:

Day 22

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

Main test: 10 control animals and 20 treated animals (10 males and 10 females).

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal injections / performed on test day 1: An area of dorsal skin from the scapular region (approximately 6 x 8 cm) was clipped free of hair. Three pairs of intradermal injections (0.1 ml/site) were made at the border of a 4 x 6 cm area in the clipped region as follows:
Test group: 1) 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.
2) The test article, diluted to 5 % with bi-distilled water
3) The test article diluted to 5 % by emulsion in a 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.

Control Group: 1) 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.
2) Bi-distilled water
3) 1:1 (w/w) mixture of bi-distilled water in a 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline.

Epidermal applications / performed on test day 8:

On test day 7 and approximately 24.5 hours prior to the epidermal application the scapular area (approximately 6 x 8 cm) was clipped, shaved free of hair and the test area was pretreated with 10 % Sodium-Lauryl-Sulfate (SLS) in paraffinum perliquidum as no primary irritation had been observed in the pretest. The SLS was massaged into the skin with a glass rod without bandaging. This 10 % concentration of SLS enhances sensitization by provoking a mild inflammatory reaction. On test day 8 a 2 x 4 cm patch of filter paper was saturated with the test article (50 % in vaselinum album) and placed over the injection sites of the test animals. The patch was covered with aluminum foil and firmly secured by an elastic plaster wrapped around the trunk of the animal and secured with impervious adhesive tape. The dressings were left in place for 48 hours. The epidermal application procedure described ensured intensive contact of the test article. The guinea-pigs of the control group were treated as described above with vaselinum album only. Reaction sites were assessed for erythema and oedema 24 and 48 hours after

B. CHALLENGE EXPOSURE
The test and control guinea-pigs were challenged two weeks after the epidermal induction application. The test and control guinea-pigs were treated in the same way. Hair was clipped and shaved from a 5 x 5 cm area on the left and right flank of each guinea-pig just prior to the application. Two patches ( 2 x 2 cm) of filter paper were saturated with the non-irritating concentration of 25 % (left flank) and the vehicle only (vaselinum album, applied to the right flank) using the same method as for the epidermal application. The dressing were left in place for 24 hours. 21 hours after removing of the dressing the test sites were depilated with an approved depilatory cream (VEET Cream, Reckitt & Colman AG, CH-4123 Allschwil).The cream was placed on the patch sites for 3-5 minutes and then washed off with a stream of warm running water. When the application sites were clean and any stains from the test article removed the animals were dried with a disposable paper towel and returned to their cages.24 and 48 hours after the removal of the dressing the application sites were assessed for erythema and oedema using the numerical scoring system according to Draize.

Positive control substance(s):

yes

Remarks:

2-MERCAPTOBENZOTHIAZOLE

Positive control results:

The intradermal induction was performed with a dilution at 5 % in mineral oil. For the induction period a 25 % dilution was selected. The non-irritating test article concentration used for challenge application was 25 % in mineral oil. 6/10 animals showed positive results.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

5 % Intradermal Induction; 50 % Epidermal induction; 25 % Epidermal challenge.

No. with + reactions:

1

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5 % Intradermal Induction; 50 % Epidermal induction; 25 % Epidermal challenge.

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

no indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

5 % Intradermal induction; 25 % Epidermal induction; 25 % epidermal challenge.

No. with + reactions:

6

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

5% Intradermal induction; 25% Epidermal induction; 25% epidermal challenge.

No. with + reactions:

6

Total no. in group:

10

Remarks on result:

positive indication of skin sensitisation

Interpretation of results:

GHS criteria not met

Conclusions:

The test article was considered to be a non-sensitiser.

Executive summary:

A guinea pig maximization study was conducted to evaluate the skin sensitisation potential of the test substance (90 % purity) according to OECD Guideline 406 and EEC Directive 92/69 with deviations. In this study, following concentration was used;

5 % test article in distilled water - intradermal induction;

50 % test article in vaselinum album - epidermal induction;

25 % test article in vaselinum album - epidermal challenge

In this study 5 % of the animals of the test group were positive after treatment with a non-irritant test substance concentration of 25 % in vaselinum album. No positive reactions were observed in the control group. The body weight of the animals was within the normal range of variability. No symptoms of systemic toxicity were observed in the animals. As there were no deaths during the course of the treatment period no necropsies were performed. The response of at least 30 % positive animals is considered positive "R43" following the "Commission Directive 93/21/EEC, April 27, 1993 adapting to technical progress for the 18th time Council Directive 67/548/EEC on the approximation of the laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances". Therefore, the test article was considered to be a non-sensitiser.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A guinea pig maximization study was conducted to evaluate the skin sensitisation potential of the test substance (90 % purity) according to OECD Guideline 406 and EEC Directive 92/69 with deviations. In this study, following concentration was used:;

5 % test article in distilled water - intradermal induction;

50 % test article in vaselinum album - epidermal induction;

25 % test article in vaselinum album - epidermal challenge

In this study 5 % of the animals of the test group were positive after treatment with a non-irritant test substance concentration of 25 % in vaselinum album. No positive reactions were observed in the control group. The body weight of the animals was within the normal range of variability. No symptoms of systemic toxicity were observed in the animals. As there were no deaths during the course of the treatment period no necropsies were performed. The response of at least 30 % positive animals is considered positive "R43" following the "Commission Directive 93/21/EEC, April 27, 1993 adapting to technical progress for the 18th time Council Directive 67/548/EEC on the approximation of the laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances". Therefore, the test article was considered to be a non-sensitiser.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the above stated assessment of the skin sensitisation potential, the substance does need to be classified as a non-sensitiser according to CLP (Regulation (EC) No 1272/2008 Of The European Parliament And Of The Council) as implementation of UN-GHS in the EU.