1-(N,N-bis(2-ethylhexyl)aminomethyl)-1,2,4-triazole

Endpoint summary

Description of key information

In a guinea pig maximization test the test article caused skin sensitization in 85-95% of the test group animals and is therefore regarded as a strong skin 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:

July - August, 1985

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

adopted May 12, 1981

Deviations:

no

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

Existing in vivo study dated 1985 available of good quality to meet this endpoint

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 LTD. Tierfarm, 4334 Sisseln, Switzerland
- Age at study initiation: 10 weeks old
- Weight at study initiation: 299-416 g
- Housing: individually in Macrolon cages
- Diet: standard guinea pig pellets, NAFAG No.846, ad libitum
- Water: ad libitum
- Acclimation period: 8 days

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

Route:

intradermal and epicutaneous

Vehicle:

other: Sesame oil and vaseline

Concentration / amount:

First induction: 1% in sesame oil
Second induction: 0.4 g paste of 30% test item
Challenge: 0.2 g paste of 30% test item

Route:

epicutaneous, occlusive

Vehicle:

other: Sesame oil and vaseline

Concentration / amount:

First induction: 1% in sesame oil
Second induction: 0.4 g paste of 30% test item
Challenge: 0.2 g paste of 30% test item

No. of animals per dose:

20

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE
The induction was a two-stage operation. First, intradermal injections (into the neck region); second, closed patch exposure over the injection sites one week later.
First induction:
Three pairs of intradermal injections (0.1 mL per injection) were made simultaneously into the shaved neck of the guinea pigs as follows: adjuvant and saline (1: 1), test item in sesame oil, test item in the adjuvant saline mixture.
- Control group: yes, treated with adjuvant and the vehicle
- Site: neck
- Concentrations: 1% solution (0.1 ml per injection)

Second induction:
One week after induction the test item was incorporated in vaseline and applied on a filterpaper patch to the neck of the animals (patch 2 x 4 cm; occluded administration for 48 hours).
The application sites were pretreated the day before with 10 % sodium lauryl sulfate (open application).
- No. of exposures: one
- Exposure period: 48 h
- Control group: yes, treated with adjuvant and the vehicle
- Site: neck
- Concentrations: 30% test item (approx. 0.4 g test item)

B. CHALLENGE EXPOSURE
Two weeks after the epidermal induction application the animals were tested on the flank with the test item in vaseline and the vehicle alone (patch 2 x 2 cm; occluded administration for 24 hours).
- No. of exposures: one
- Day(s) of challenge: Two weeks after the epidermal induction application
- Exposure period: 24 h
- Control group: yes, treated with the vehicle as well as with the test compound
- Site: flank
- Concentrations: 30% test item (approx. 0.2 g test item)
- Evaluation (hr after challenge): 24 h and 48 h

C. CONTROL GROUP
A control group was treated with adjuvant and the vehicle during the induction period. During the challenge period the group was treated with the vehicle as well as with the test compound (at least 10 animals) to control the maximal subirritant concentration of the test item in adjuvant treated animals.

Positive control substance(s):

no

Positive control results:

The sensitivity of the strain was checked every six months with Paraphenylene-diamine or Potassium-dichromate.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

30%

No. with + reactions:

19

Total no. in group:

20

Remarks on result:

positive indication of skin sensitisation

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

30%

No. with + reactions:

17

Total no. in group:

20

Remarks on result:

positive indication of skin sensitisation

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

30%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

30%

No. with + reactions:

0

Total no. in group:

20

Remarks on result:

no indication of skin sensitisation

Group:

positive control

Remarks on result:

not measured/tested

Interpretation of results:

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

Conclusions:

85 to 95% of the animals were sensitised by the test article under the experimental conditions employed. The test substance is therefore regarded a skin sensitizer.

Executive summary:

In a guinea pig maximization test according to OECD guideline No. 406, 10 male and 10 female animals were first induced and then challenged with the test article to investigate its sensitization potential. Induction was a two-stage operation: First, three pairs of intradermal injections (0.1 ml per injection) were made into the shaved neck of the animals with a 1:1 mixture (v/v) of adjuvant/saline, 1% of the test substance in sesame oil, and 1% of the test substance in a 1:1 mixture (v/v) of adjuvant/ saline. One week later the test article was incorporated in vaseline (30% concentration) applied on a filter paper patch to the neck of the animals (patch 2 x 4 cm; 0.4 g, occluded administration for 48 hours). The application sites were pretreated on the previous day with 10 % sodium lauryl sulfate (open application). Two weeks after the epidermal induction application the animals were tested on the flank with 30% test substance in vaseline and the vehicle alone (patch 2 x 2 cm; 0.2 g, occluded administration for 24 hours). A control group of 10 males and 10 females was treated with adjuvant and the vehicle during the induction period. During the challenge period the group was treated with the vehicle as well as with the test compound (at least 10 animals) to control the maximal subirritant concentration of the test compound in adjuvant treated animals. Twenty four hours after removing the dressings the challenge reactions were graded according the Draize scoring scale.

A second evaluation was made 48 hours after removing the dressings. At the 24 hour time point, 19/20 animals of the test group showed dermal irritation reactions. At the 48 hour time point, 17/20 animals were positive. None of the animals of the control group showed reactions either treated with the vehicle or with the test compound during challenge. In conclusion, under the experimental conditions employed, 85 to 95% of the animals of the test group showed skin reactions 24 and 48 hours after removing the dressings. The test article is therefore regarded as a skin sensitizer in albino guinea pigs and requires classification.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The test substance was investigated for its sensitizing potential in a GLP-compliant Maximization test according to OECD guideline 406 (CIBA-GEIGY Ltd., 850296, 1985). Pirbright White guinea pigs received intradermal induction treatments with 1% in sesame oil and one epicutanous induction treatment with 30% in vaseline. For intradermal induction, three pairs of injections (adjuvant/saline; test item in vehicle; test item in adjuvant/saline) were given into the neck, one week later the epicutanous induction was performed occlusively over the same test sites. Epidermal challenge was performed by occlusive application on the flank for 24 h two weeks later (30% in Vaseline). Dermal reactions were assessed 24 and 48 hours after removal of the patches. Concurrent negative vehicle control animals were treated with adjuvant and the vehicle during the induction period and with the vehicle as well as with the test compound during the challenge period. 19/20 and 17/20 animals of the test group showed positive skin reactions at the 24 and 48 hour time point, respectively. None of the animals of the control group showed skin reactions. In conclusion, under the experimental conditions employed, 85 to 95% of the animals of the test group showed skin reactions 24 and 48 hours after removing the dressings. The test article is therefore regarded as a skin sensitizer in albino guinea pigs and requires classification.

This result was confirmed in a modified maximization test performed with Pirbright White guinea pigs (CIBA-GEIGY Ltd., 884219, 1988). In this study, the induction treatment was modified in the following manner: First, 0.1 ml of a freshly prepared adjuvant saline mixture (1:1) was injected intracutaneously at 4 sites into the animals’ neck. Then, the undiluted test item (approx. 0.4 g) was applied occlusively on a filter paper patch over the adjuvant injection sites for 24 hours. One week later 0.4 g of the undiluted test substance was again applied occlusively on the adjuvant injection sites for 48 hours. Epidermal challenge was performed by occlusive application for 24 h on the flank two weeks later (approx. 0.2 g, undiluted). Dermal reactions were assessed 24 and 48 hours after removal of the patches. Concurrent negative vehicle control animals were treated with adjuvant and the vehicle during the induction period and with the vehicle as well as with the test compound during the challenge period. 13/20 and 12/20 animals of the test group showed positive skin reactions at the 24 and 48 hour time point, respectively. None of the animals of the control group showed skin reactions. In conclusion, under the experimental conditions employed, 65% of the animals of the test group showed skin reactions after removing the dressings. The test article is therefore regarded as a skin sensitizer in albino guinea pigs.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The available experimental test data are reliable and suitable for the purpose of classification under Regulation (EC) No.1272/2008.

Based on the data, the test substance requires classification for skin sensitization.