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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:
other: Meets generally accepted scientific standards, well documented and acceptable for assessment.

Data source

Referenceopen allclose all

Reference Type:
other company data
Title:
Unnamed
Year:
1978
Report Date:
1977
Reference Type:
study report
Title:
Unnamed
Year:
1978
Report Date:
1978

Materials and methods

Principles of method if other than guideline:
The test procedure was based on the description in the Code of Federal Regulations 16 (commercial practices) Chapter II, part 1500.41, January 1, 1977.
Six male albino rabbits were treated with test substance at two abraded and two intact sites of the skin. After 24 hours the occluded patch was removed and the first reading was done. After 72 hours the second reading was performed and the primary dermal irritation index was determined.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
no data

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
Weight: 2 - 2.5 kg
Individual housing.

Test system

Type of coverage:
occlusive
Preparation of test site:
other: abraded and intact
Vehicle:
water
Controls:
yes, concurrent vehicle
Amount / concentration applied:
0.5 g
Duration of treatment / exposure:
24 hour
Observation period:
72 hours
Number of animals:
6
Details on study design:
TEST SITE:
Four areas, two on each side of the rabbit´s back, approximately 10 cm apart, were utilized for substance administration. The hair on the backs of the animals was removed with an electric clipper. Two of the four sites were abraded, two were left intact. Abrations were made with a 24-gauge hypodermic needle and consisted of three superficial incisions 1 cm long and 0.5 cm apart. Abrasions were made to the stratum corneum.

EXPOSURE:
0.5 g of solid test substance was applied directly to a coverlet, dissolved in water and applied using a surgical gauze pad (1"x1"). The entire trunk was wrapped with an impervious material for the 24-h exposure period.

READING:
After 24 h the patches were removed and remained off for the duration of the experiment. Readings were performed 1, 24 and 72h following the exposure period.

INTERPRETATION:
An average irritation score was calculated for intact and abraded skin by adding the total irritation scores at 24 and 72 divided by the number of values. The primary dermal irritation index was determined by averaging the average irritation scores of the intact and abraded skin.
Two negative (blank preparation and destilled water) and a positive control (5% sodium lauryl sulfate) were also tested.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
primary dermal irritation index (PDII)
Basis:
mean
Time point:
other: 24 and 72 h
Score:
0.08
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: 24 and 72 h
Score:
0
Max. score:
4
Reversibility:
other: no effects
Remarks on result:
other: intact skin
Irritation parameter:
edema score
Basis:
mean
Time point:
other: 24 and 72 h
Score:
0
Max. score:
4
Reversibility:
other: no effects
Remarks on result:
other: intact skin
Irritation parameter:
erythema score
Basis:
mean
Time point:
other: 24 and 72 h
Score:
0.17
Max. score:
4
Reversibility:
fully reversible within: 72 h
Remarks on result:
other: abraded skin
Irritation parameter:
edema score
Basis:
mean
Time point:
other: 24 and 72 h
Score:
0
Max. score:
4
Reversibility:
other: no effects
Remarks on result:
other: abraded skin
Irritant / corrosive response data:
The PDII reveals a mild irritating effect of the test substance. The effect was only observed in abraded skin. However, a similar mildly irritating effect was observed in control animals on abraded skin.
The positive control (sodium lauryl sulfate) resulted in severe skin irritation on intact and abraded skin (PDII 6 or 5.5).

Any other information on results incl. tables

MDA did not cause dermal irritation on New Zeeland albino rabbits after topical application.

Applicant's summary and conclusion