4-(4-nitrophenylazo)-2,6-di-sec-butyl-phenol

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This study was carried according to OECD Guideline No. 404 and EEC Directive 84/449/EEC, Part 8.4 and in accordance with the Principles of Good Laboratory Practices (GLP) as the remanants of the test substance could not be removed from the treatment area and the scores were from approximately 25% of the exposed area.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

Principles of method if other than guideline:

not applicable

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

MORTRACE SB CONC.

IUPAC Name:

MORTRACE SB CONC.

Constituent 2

Reference substance name:

4-(4-Nitrophenylazo)-2,6-di- sec.butylphenol

IUPAC Name:

4-(4-Nitrophenylazo)-2,6-di- sec.butylphenol

Constituent 3

Reference substance name:

4-(4-nitrophenylazo)-2,6-di-sec-butyl-phenol

EC Number:

410-610-2

EC Name:

4-(4-nitrophenylazo)-2,6-di-sec-butyl-phenol

Cas Number:

111850-24-9

Molecular formula:

C20 H25 N3 O3

IUPAC Name:

2,6-bis(butan-2-yl)-4-[2-(4-nitrophenyl)diazen-1-yl]phenol

Test material form:

other: dark red-brown liquid

Details on test material:

- Name of test material (as cited in study report): Mortrace SB Conc.
- Physical state: dark red-brown liquid
- Analytical purity: concentrate
- Lot/batch No.: MR 26592 SBC
- Expiry date: June 03, 1993
- Stability under storage conditions: stable
- Storage condition of test material: at room temperature protected from light

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Broekman Institute, Someren, The Netherlands
- Age at study initiation: approximately 13 weeks
- Weight at study initiation: 2748 - 3096 grams
- Housing: individually housed
- Diet: standard rabbit pelleted diet provided approximately 100 grams/day
- Water: ad libitum
- Acclimation period: at least 5 days before start of treatment

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21°C
- Humidity (%): 55%
- Air changes (per hr): 15 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours light/dark cycle

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

0.5 grams

Duration of treatment / exposure:

4 hours

Observation period:

The skin reactions were assessed at approximately 45 minutes, 24, 48 and 72 hours and 7, 14 and 21 days after the removal of the dressings and test substance.

Number of animals:

3 male rabbits

Details on study design:

Approximately 24 hours before treatment, the dorsal fur was shaved with electric clippers, exposing an area of approximately 150 square centimeters (10 cm x 15 cm).
Prior to test substance administration, the animals were physically examined and the shaved area of skin to be treated was normal.
On test day 1, 0,5 gram of the test substance was applied to the intact skin of the shaved area on one flank, using a Scotchpak non-woven patch (2x3 cm, 3M, St.Paul, U.S.A.) mounted on Micropore tape (3M, St. Paul, U.S.A.). The contralateral flank was similarly prepared (but without test substance) to act as a procedural control. The dressing was wrapped around the abdomen and secured with an elastic bandage (Coban, 3M, St. Paul, U.S.A.).
Four hours after the application, the dressing was removed and an attempt was made to remove the remaining test substance, using a tissue moistened with tap water and subsequently a dry tissue. However, a brown/yellow sticky layer remained in the treated area.
In order to facilitate the scoring, the skin sites concerned of all animals were reshaved before the observation on days 2, 3, 4, 15 and 22. However, reshaving on days 2, 3 and 4 of the treated skin sites was difficult due to the presence of sticky remnants of’ the test substance.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal: rabbit # 3987

Time point:

other: 24, 48 and 72 hours

Score:

0

Reversibility:

other: not applicable

Results 2

Irritation parameter:

erythema score

Basis:

animal: rabbit # 3988

Time point:

other: 24, 48 and 72 hours

Reversibility:

other: No data

Remarks on result:

not determinable

Remarks:

Erythema could not be scored due to the presence of a brown/yellow, sticky layer of remnants of the test substance in the area of application.

Results 3

Irritation parameter:

erythema score

Basis:

animal: rabbit # 3989

Time point:

other: 24, 48 and 72 hours

Reversibility:

other: No data

Remarks on result:

not determinable

Remarks:

Erythema could not be scored due to the presence of a brown/yellow, sticky layer of remnants of the test substance in the area of application

Results 4

Irritation parameter:

edema score

Basis:

animal: rabbit #3987

Time point:

other: 24, 48 and 72 hours

Score:

1.3

Max. score:

2

Reversibility:

fully reversible within: 14 days

Results 5

Irritation parameter:

edema score

Basis:

animal: rabbit # 3988

Time point:

other: 24, 48 and 72 hours

Score:

1.3

Max. score:

1

Reversibility:

fully reversible within: 14 days

Results 6

Irritation parameter:

edema score

Basis:

animal: rabbit # 3989

Time point:

other: 24, 48 and 72 hours

Score:

1.3

Max. score:

2

Reversibility:

not fully reversible within: 21 days

Irritant / corrosive response data:

The test substance could not be removed from the treated skin sites after the 4 hour exposure. The presence of a brown/yellow, sticky layer made scoring of (large parts of) the skin sites impossible for erythema and/or oedema for the first four days of the study. The parts of’ the skin that could be scored, showed no or very slight erythema and very slight or slight oedema. At the observation 7 days after exposure the treated skin sites of all three animals were noted to be bald and showed moderate to severe erytherna and very slight oedema. The sites were covered with a thick layer of scales, mixed with remnants of the test substance. The skin irritation had resolved within 14 days after exposure in animals 3987 and 3988. Slight skin irritation and scaliness persisted in animal 3989 at the 14-day and 21-day observations. The treated skin of all three animals was still noted to be bald at the final observation.
There was no evidence of a corrosive effect on the skin.

Other effects:

A brown/yellow sticky layer of remnants of the test substance could not be removed from the treated area after the 4 hour exposure period and was also noted at the observations on days 1 to 4 in all three animals. Brown/yellow remnants of the test substance were still noted in the treated area on day 8 in all three animals and on days 15 and 22 in animal 3989.
No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

Any other information on results incl. tables

Individual scores

24 hours-

Rabbit	Erythema	Edema	Comments
3987	0	2	Approx. 75% of the treated area could not be scored due to the presence of a brown/yellow, sticky layer of remnants of the test substance.
3988	-	1	Oedema could be scored for approx. 25% of the treated area. Scoring of the remaining area was impossible due to the presence of remnants of the test substance.
3899	-	1	same as above

- Erythema could not be scored due to the presence of a brown/yellow, sticky layer of remnants of the test substance in the area of’ application.

48- hours-

Rabbit	Erythema	Edema	Comments
3987	0	1	Approx. 75% of the treated area could not be scored due to the presence of a brown/yellow, sticky layer of remnants of the test substance.
3988	-	1	In animals 3988 and 3989, oedema could be scored forapprox. 25% of the treated area. Scoring of the remaining area was impossible due to the presence of remnants of the test substance.
3899	-	1	same as above

- Erythema could not be scored due to the presence of a brown/yellow, sticky layer of remnants of the test substance in the area of’ application.

72 -hours-

Rabbit	Erythema	Edema	Comments
3987	0	1	In all three animals, both erythenia and oederna could be scored for approx. 25% of the treated area. Scoring of the remaining area was impossible due to the presence or a brown/yellow, sticky layer of remnants of the test substance.
3988	1	2	same as above
3899	1	2	same as above

- Erythema could not be scored due to the presence of a brown/yellow, sticky layer of remnants of the test substance in the area of’ application.

7 days-

Rabbit	Erythema	Edema	Comments
3987	3	1	In all three animals a thick layer of scales, mixed with brown/yellow remnants of the test substance, was seen in the area of application. Underneath, a bald skin with erythema score 3 was observed.
3988	3	1	same as above
3899	3	1	same as above

14 days-

Rabbit	Erythema	Edema	Comments
3987	0	0	In all three animals, approx. 80% of’ the treated skin was noted to be bald. Scaliness, mixed with orange/yellow remnants of the test substance, was noted in approx. 50% of the treated area of animal 3989.
3988	0	0	same as above
3899	0	1	same as above

21 days-

Rabbit	Erythema	Edema	Comments
3987	0	0	In all three animals, approx. 80% of the treated skin was noted to be bald. In animal 3989, the bald skin showed erythema score 1 and scaliness, mixed with orange/yellow remnants of’ the test substance, was noted at the edges of the treated area.
3988	0	0	same as above
3899	1	2	same as above

Applicant's summary and conclusion

Interpretation of results:

irritating

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

Using the available scores a primary irritation index of 1.8 was calculated, indicating that MORTRACE SB CONC. was mildly irritating to the rabbit skin. However, the appearance of a bald skin, moderate to severe erythema and scaliness 7 days after exposure indicate that the scores obtained at the 24 to 72 hour observations were probably an underestimation of the irritating potential. Therefore, for the purpose of safety evaluation, NORTRACE SB CDNC. was considered moderately irritating.

Executive summary:

The purpose of this study was to assess the possible skin irritation or skin corrosion potential of MORTRACE SB CONC. in rabbits.

This study was carried out in accordance with DECO Guideline No. 404, “Acute Dermal Irritation / Corrosion” and EEC Directive 84/449/EEC, Part 8.4, “Acute Toxicity - Skin Irritation”.

MORTRACE SB CONC. was applied onto shaved skin of three male albino rabbits using semi-occlusive dressings for 4 hours, followed by seven observations at approximately 1, 24, 48 and 72 hours and 7, 14 and 21 days after removal of the dressings and remaining test substance.

The test substance could not be removed from the treated skin sites and made scoring impossible and/or difficult during the first four days of the study. The parts of the skin that could be scored, showed only slight irritation. 7 Days after exposure a bald skin, scaliness and moderate to severe erythema and very slight oedema were noted in all three animals. The skin irritation had resolved within 14 days after exposure in two animals and slight skin irritation and scaliness persisted in one animal untill termination (day 22). There was no evidence of a corrosive effect on the skin.

No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

A primary irritation index of 1.8, calculated using the available scores, indicate that MORTRACE SB CONe, was mildly irritating to the rabbit skin. However, based on the clinical signs noted from day 7 onwards the test substance was considered moderately irritating, for the purpose of safety evaluation.

Due to the absence of critical scores, classification of MORTRACE SB CONC. in accordance to the EEC criteria for general classification and labelling requirements for dangerous substances and preparations (EEC Directive 91/325/EEC, Amendment to Annex VI of the EEC Directive 67/548/EEC) was difficult. The clinical signs observed from day 7 onwards indicated an irritating potential of the test substance when applied to the rabbit skin. Therefore it was considered that MORTRACE SB CONC. should be labelled as a skin irritant.