(4-nonylphenoxy)acetic acid

Endpoint summary

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:

25.03.1985 - 25.04.1985

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study was performed according to OECD guidelines, no GLP statement, however QAU statement is included.

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

(1981)

Qualifier:

according to guideline

Guideline:

other: EEC directive 79/831

GLP compliance:

no

Remarks:

but QAU statement included

Type of study:

guinea pig maximisation test

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
- Age at study initiation: 10 weeks
- Weight at study initiation: 291 - 420 g
- Housing: individually in Macrolon cages (type 3)
- Diet: ad libitum standard guinea pigs pellets - NAFAG No. 846, Gossau SG supplemented with fresh carrots
- Water: ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 +/- 2
- Humidity (%): 50 +/- 10
- Photoperiod (hrs dark / hrs light): 12/12

Route:

intradermal and epicutaneous

Vehicle:

other: intradermal: sesame oil; epidermal: vaseline

Concentration / amount:

1% for intradermal application in sesame oil and saline adjuvant mixture
3% for epidermal application (Induction) in vaseline, about 0.4 g per patch
0.3% for epidermal application (Challenge) in vaseline, about 0.2 g per patch

Route:

epicutaneous, open

Vehicle:

other: intradermal: sesame oil; epidermal: vaseline

Concentration / amount:

1% for intradermal application in sesame oil and saline adjuvant mixture
3% for epidermal application (Induction) in vaseline, about 0.4 g per patch
0.3% for epidermal application (Challenge) in vaseline, about 0.2 g per patch

No. of animals per dose:

20 in test group, 10 in control group

Details on study design:

RANGE FINDING TEST
The concentrations of the test compound for induction and challenge periods were determined on separate animals. (no details given in the report).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (three pairs of intradermal injections and one epidermal applications)
- Exposure period: 48 hours (epidermal patch)
- Test group: 3 pairs of injections: Mixture of adjuvant and saline; test compound in vehicle; mixture of test compound in vehicle plus adujvant/saline mixture
- Control group: treated with adjuvant and vehicle
- Site: neck
- Duration: 1 week (intradermal induction) and 2 weeks (epidermal induction)
- Concentrations: 1% intradermally and 3% epidermally

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: two weeks after epidermal induction
- Exposure period: 24 hours
- Test groups: test substance
- Control group: treated with the vehicle as well as with test compound
- Site: flank
- Concentrations: 0.3%
- Evaluation (hr after challenge): 24 hours and 48 hours

Challenge controls:

The sensitivity of the strain is controlled every six month with p - phenylenediamine

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

1 % intradermal, 0.3 % challenge

No. with + reactions:

15

Total no. in group:

20

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 1 % intradermal, 0.3 % challenge. No with. + reactions: 15.0. Total no. in groups: 20.0.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

1 % intradermal, 0.3 % challenge

No. with + reactions:

15

Total no. in group:

20

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 1 % intradermal, 0.3 % challenge. No with. + reactions: 15.0. Total no. in groups: 20.0.

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0 % intradermal, 0.3 % challenge

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 0 % intradermal, 0.3 % challenge. No with. + reactions: 0.0. Total no. in groups: 10.0.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0 % intradermal, 0.3 % challenge

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 0 % intradermal, 0.3 % challenge. No with. + reactions: 0.0. Total no. in groups: 10.0.

Interpretation of results:

sensitising

Remarks:

Migrated information

Conclusions:

75% of the animals were sensitized by the test article under the experimental conditions employed. The test article, is therefore considered to be a skin sensitizer.

Executive summary:

 In a maximization test according to OECD guideline 406 and performed under QAU surveillance, the test article was tested for sensitizing potential in Pirbright White guinea pigs. The test animals were first induced with three pairs of intradermal injections (adjuvant/saline; 1% test item in sesame oil; 1% test item in sesame oil plus adjuvant/saline). One week later, the animals were treated epicutanously for 48 hours with 3% test material in vaseline. Control animals received the vehicle alone during induction. Two weeks after induction, the animals were challenged by occlusive epicutaneous exposure (0.3 % concentration) for 24 hours. During the challenge, the control group was treated with the vehicle as well as with the test compound 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 is made 48 hours after removing the dressings. In the test group, 15/20 animals showed skin reactions, whereas in the control group no skin reactions could be observed. In animals treated with the vehicle alone, no skin reactions could be observed either. The test article is therefore considered to be skin sensitizing and requires classification. The sensitivity of the strain is controlled every six month with p – phenylenediamine.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

The skin sensitizing properties of the test article were investigated in a valid maximization study (Ciba Geigy, 1985) based on the OECD guideline 406. Although not performed under GLP, the study was performed under GLP-like QAU surveillance and is reported in sufficient detail. Induction was a two stage operation. First, the test animals received three pairs of intradermal injections (adjuvant/saline; 1% test item in sesame oil; 1% test item in sesame oil plus adjuvant/saline). One week later, the animals were treated epicutaneously for 48 hours with 3% test material in vaseline. Two weeks after induction, the animals were challenged by occlusive epicutaneous exposure (0.3 % concentration) for 24 hours. 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 to control the maximal subirritant concentration of the test compound in adjuvant treated animals. In the test group, 15/20 animals showed skin reactions, whereas in the control group no skin reactions could be observed. In animals treated with the vehicle alone, no skin reactions could be observed either. The test article is therefore considered to be skin sensitizing and requires classification.

Migrated from Short description of key information:
The substance was found to be sensitizing in a guinea pig maximization test ( Ciba Geigy, 1985). 75% of test group animals induced intradermally and epidermally with the test article (1% and 3 %, respectively) showed skin reactions after epidermal challenge (with 0.3 %).

Justification for selection of skin sensitisation endpoint:
OECD guideline study

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available study is considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance requires classification with R43 for skin sensitization under Directive 67/548/EEC.

 

Classification, Labeling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance requires classification for skin sensitization Cat. 1A under Regulation (EC) No. 1272/2008.