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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Justification for type of information:
data is from experimental report

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Principles of method if other than guideline:
To evaluate the dermal irritation potential of the test chemical in New Zealand white rabbits
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: Off white crystalline powder
Details on test material:
- Name of test material (as cited in study report): tert-butyl-4-methoxyphenol
- Substance type: Organic
- Physical state: Solid

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
Source : Institute for Industrial Research & Toxicology
Age : 10 to 12 weeks
Sex : Female
Body weight range : 1.80kg±200g
Identification : By cage tag and corresponding colour body marking
Environmental conditions : Air conditioned rooms with 10-15 air changes per hour, temperature between 22-25 deg C, relative humidity 40-60% and illumination cycle set to 12 hours artificial fluorescent light and 12 hours dark.
Accommodation : Animals were housed individually in stainless steel cages provided with stainless steel mesh bottom and facilities for food and water bottle.
Diet : Pelleted feed supplied by Pranav agro Industries Ltd., B7/6 Ramesh Nagar, Delhi
Water : Community tap water passed through ‘Aqua Guard on line water filter’, was kept in glass bottles, ad libitum

Test system

Type of coverage:
occlusive
Preparation of test site:
shaved
Vehicle:
unchanged (no vehicle)
Controls:
not specified
Amount / concentration applied:
0.5 gm of test compound
Duration of treatment / exposure:
no data
Observation period:
upto 14 days after application
Number of animals:
Three
Details on study design:
Details on study design
TEST SITE
- Area of exposure: dorsal area of the trunk
- % coverage:approx 6 square cm
- Type of wrap if used: impervious dressing
REMOVAL OF TEST SUBSTANCE
- Washing (if done): yes
- Time after start of exposure: after patch removal, the site of application was cleaned with luke warm
water
OBSERVATION TIME POINTS
(indicate if minutes, hours or days) : 1, 24,48 and 72 hours
SCORING SYSTEM: The intact skin site of application was observed for erythema and edema and scored according to Draize method

Results and discussion

In vivo

Results
Irritation parameter:
overall irritation score
Basis:
mean
Time point:
24/48/72 h
Score:
1.67
Max. score:
4
Reversibility:
fully reversible
Remarks on result:
positive indication of irritation
Irritant / corrosive response data:
The test compound when applied at the dose level of 0.5 gm on shaven back skin of rabbit produced slight redness after 4 hours of patch removal. However, no other skin reaction was observed throughout the study period.
Other effects:
The test compound tert-butyl-4-methoxyphenol applied on the shaven back skin of rabbit did not produce any clinical signs of toxicity throughout the examination period of 14 days.

Any other information on results incl. tables

TABLE – 1

INDIVIDUAL ANIMAL DERMAL IRRITATION SCORES

Rabbit No.

Sex

INTACT SKIN

3 Min.

4 Hours

24 Hours

48 Hours

72 Hours

14 days

Erythema

Oedema

Erythema

Oedema

Erythema

Oedema

Erythema

Oedema

Erythema

Oedema

Erythema

Oedema

01

F

0

0

1

0

1

0

0

0

0

0

0

0

02

F

-

-

1

0

0

0

0

0

0

0

0

0

03

F

-

-

1

0

1

0

0

0

0

0

0

0

Total

0

0

3

0

2

0

0

0

0

0

0

0

Mean

0

0

1

0

0.67

0

0

0

0

0

0

0

Grand Total

1.67

Dermal Irritation Index: 1.67/4 = 0.42

Applicant's summary and conclusion

Interpretation of results:
Category 2 (irritant) based on GHS criteria
Conclusions:
The dermal irritation index of the test chemical in New Zealand white rabbits was calculated as 0.42 and test compound can be considered as slightly irritating to the skin of the New Zealand white rabbits under test condition.
Executive summary:

A dermal irritation study was conducted on New Zealand white rabbits in accordance with OECD 404 to assess the irritation parameter of the test chemical.

In the initial test one healthy rabbit of body weight 2.00 kg was selected for the study after acclimatization. The test compound in the amount of 0.5 gm was applied at the different sites on the shaven back skin of animal. The hairs of back sides were removed (approximately 6 cm2) one day earlier before the treatment. The test substance in the amount of 0.5 gm was applied to a small area (approximately 6 cm2) of skin and covered with a gauze patch, which was held in place with non-irritating tape. The first patch was applied on the shaven back skin of rabbit and removed after three minutes. No serious reaction was observed at the site of application. The second patch was applied on the different shaven back side and removed after one hour. There were no signs of skin reaction observed at this site of application. Finally, a third patch was applied at a different site and was removed after four hour. Slight redness was observed at the site of application of test compound after four hour patch removal. This condition was recovered after 24 hours. Finally, the animal was observed for 14 days, for any irritation and corrosion.

 

Because no corrosive effect observed in the initial test, a confirmatory test was done in order to confirm the irritant or negative response of the test substance by using two additional animals. In the confirmatory test the test compound in the amount of 0.5 gm was applied on the shaven back skin of two animals, each with one patch, for an exposure period of four hours. After four hours the patch was removed and the skin reactions were graded according to Draize’s method. The test compound produced slightly redness after four hour patch removal upto 24 hours. There were no other clinical signs and symptoms recorded during the entire observation period.

 The dermal irritation index of the test chemical in New Zealand white rabbits was calculated as 0.42 and test compound can be classified under "Slight irritant ".