2-[(o-nitrophenyl)azo]-p-cresol

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report date:

1996

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-[(o-nitrophenyl)azo]-p-cresol

EC Number:

215-863-0

EC Name:

2-[(o-nitrophenyl)azo]-p-cresol

Cas Number:

1435-71-8

Molecular formula:

C13H11N3O3

IUPAC Name:

4-methyl-2-[(2-nitrophenyl)diazenyl]phenol

Details on test material:

- Identification: TKA 40136
- Product name: Monoazo 3113
- Physical state: Red-brownish solid
- Analytical purity: > 95%
- Lot/batch No.: Pa 369
- Expiration date of the lot/batch: November 01, 1997
- Stability under storage conditions: stable
- Stability in vehicle (water): not known
- Storage condition of test material: At room temperature in the dark

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Broekman Institute, Someren, Netherlands
- Age at study initiation: Approx. 8 weeks
- Weight at study initiation: 1563 - 1788 grams
- Housing: single
- Diet: Standard laboratory rabbit diet (LKK-20, pellet diameter 4 mm, Hope Farms, Woerden, Netherlands), approximately 100 gram per day; in addition, hay (BMI, Helmond, Netherlands) was provided once a week;
- Water: Free access to tap-water diluted with decalcified water;
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21
- Humidity (%): 50
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: A pre-test revealed that the test substance was hydrophobic. Therefore the skin of the animals was moistened with distilled water, to ensure close contact of the test substance to the skin.

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3 male rabbits

Details on study design:

TEST SITE
- Area of exposure: approximately 150 square centimeters (10x15 cm2)
- Type of wrap if used: Scotchpak-non-woven patch of 2x3 cm mounted on Micropore tape, which was wrapped around the abdomen and secured with Coban elastic bandage (3M, St. Paul, USA).


REMOVAL OF TEST SUBSTANCE
- Washing (if done): The remaining test substance was removed using a tissue moistened with tap-water and subsequently a dry tissue.
- Time after start of exposure: 4 hours


SCORING SYSTEM: according to OECD 404 / Draize; the calculation of the primary irritation index is based on Draize et.al. (1944), J.Pharmacol.Exp. 82, 377

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Remarks:

(animal 1-3)

Time point:

other: 24 - 48 - 72 hours

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Remarks on result:

other: No erythema score available 1 hour after exposure due to brown/red staining. Erythema (score 1) in all animals 24 hours after the exposure (reversible within 24 hours). See table below for details.

Results 2

Irritation parameter:

edema score

Basis:

mean

Remarks:

(animal 1-3)

Time point:

other: 24 - 48 - 72 hours

Score:

0

Max. score:

4

Reversibility:

other: no effects observed

Remarks on result:

other: Edema (score 1) in 1 animal 1 hour after exposure (reversible within 24 hours). See table below for details.

Irritant / corrosive response data:

Brown/red staining of the treated skin by the test substance was observed during the observation period, and prevented scoring for erythema at 1 hour post exposure.

Other effects:

No signs of systemic intoxication were observed during the study period.

Any other information on results incl. tables

Exposition:	4 h
Animal	Reading	Erythema	Edema	Symptoms
1	1 h	/	1	No erythema score possible due to brown/red staining.
2	1 h	/	0	No erythema score possible due to brown/red staining.
3	1 h	/	0	No erythema score possible due to brown/red staining.
1	24 h	1	0	Brown/red staining of skin by test substance.
2	24 h	1	0	Brown/red staining of skin by test substance.
3	24 h	1	0	Brown/red staining of skin by test substance.
1	48 h	0	0	Brown/red staining of skin by test substance.
2	48 h	0	0	Brown/red staining of skin by test substance.
3	48 h	0	0	Brown/red staining of skin by test substance.
1	72 h	0	0	Brown/red staining of skin by test substance.
2	72 h	0	0	Brown/red staining of skin by test substance.
3	72 h	0	0	Brown/red staining of skin by test substance.
Mean (animal 1)	24 - 72 h	0.3	0.0
Mean (animal 2)	24 - 72 h	0.3	0.0
Mean (animal 3)	24 - 72 h	0.3	0.0
mean	24 - 72 h	0.3	0.0

Dermal application of the test substance resulted in a primary irritation index of 0.5 (mildly irritating) when applied to the intact rabbit skin.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The substance is considered not irritant to skin.