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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
Study period:
15 NOV 2006 - 07 DEC 2006
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
This study was conducted according to Good Laboratory Practice (GLP) and followed the OECD Guideline for Testing of Chemicals No 404. Only one test animal was used.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Version / remarks:
April 24, 2002
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)
Version / remarks:
December 29, 1992
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline

Test animals

Species:
rabbit
Strain:
New Zealand White
Remarks:
Crl:KBL
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Wiga GmbH, Kißlegg
- Age at study initiation: about 18 week
- Weight at study initiation: 3.98 kg (one female animal)
- Housing: special rabbit cage (manufacturer: Becker; type K99/30 KU, floor area about 5400 cm2, a shelter with an integrated sitting board of about 1820 cm2; overall height: 60 cm) with plastic grids placed on mobile racks
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16 to 18 °C
- Humidity (%): 47 to 67 %
- Air changes (per hr): air-conditioned room
- Photoperiod (hrs dark / hrs light): 12-hour light and a 12-hour dark

Test system

Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
other: paraffin oil
Controls:
not required
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g

VEHICLE
Liquid paraffin
- Amount(s) applied (volume or weight with unit): some drops
- Lot/batch no. (if required): K32250274
Duration of treatment / exposure:
4 hours
Observation period:
21 days
Number of animals:
One female animal
Details on study design:
TEST SITE
- Area of exposure: left side
- % coverage: 6 cm2
- Type of wrap if used: adhesive fabric (Fixomull® stretch, Beiersdorf), semi-occlusive

REMOVAL OF TEST SUBSTANCE
- wiped off dry

OBSERVATION TIME POINTS
1, 24, 48, 72 hours after removal of patches and then daily up to day 22

SCORING SYSTEM:
- Method of calculation: Skin changes at the application sites were evaluated according to the DRAIZE-, OECD-and EEC recommendations.

Grading scale for evaluation:

Erythema and eschar formation

Scores
--------------------------------------------------
No erythema 0

Very slight erythema (barely perceptible) 1

Well defined erythema 2

Moderate to severe erythema 3

Severe erythema (beet redness) to eschar
formation preventing grading of erythema 4
--------------------------------------------------
Maximum possible: 4
--------------------------------------------------

Edema formation
Scores
--------------------------------------------------
No edema 0

Very slight edema (barely perceptible) 1

Slight edema (edges of area well
defined by definite raising) 2

Moderate edema (raised approx. 1 mm) 3

Severe edema (raised more than 1 mm
and extending beyond area of exposure) 4
--------------------------------------------------
Maximum possible: 4
--------------------------------------------------

Total possible irritation score (maximum): 8

Mean score = Mean grading for erythema or edema of all the rabbits per time point
Mean cumulative score = Mean grading of all readings for erythema and edema per time point
Mean score per animal = Mean grading for each animal of erythema or edema (24, 48, and 72 hours after removal of the patches)

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
2.33
Max. score:
3
Reversibility:
fully reversible within: 9 days
Remarks on result:
probability of moderate irritation
Irritation parameter:
edema score
Basis:
animal #1
Time point:
24/48/72 h
Score:
1.67
Max. score:
2
Reversibility:
fully reversible within: 6 days
Remarks on result:
probability of weak irritation
Irritant / corrosive response data:
After a single application to the intact dorsal skin of a rabbit, for 4 hours under semiocclusive conditions, erythema (scores 1 to 4) were observed from day 1 up to day 9 and edema (scores 1 to 2) were observed from day 2 up to day 5 of the study. Furthermore brittle skin from day 6 up to day 9 and small scales from day 10 up to day 17 of the study were seen at the site of application. From day 18 up to the end of the experimental part increased growth of hair was observed.
Other effects:
None

Any other information on results incl. tables

Symptoms

No signs of clinical toxicity were detected.

Mortality

The animal survived the observation period.

Body weight

Body weight development of the treated rabbit was inconspicuous.

Pretests

Prior to testing the pH of a preparation was determined with pH-test strips. The pH could not be measured, as the test material was an oily liquid.

The test material was screened for its irritating potential using the hen's egg test on the chorioallantoic membrane (HET-CAM) as described below.

Fertile hen eggs, on day 10 of incubation, provided the test system. The egg shell was entered above the air cell by a dentist's rotary and then pared off the shell with the attached outer membrane and inner egg membrane was carefully opened. After the membrane had been moistened with isotonic sodium chloride solution, it was removed to expose the chorioallantoic membrane (CAM) of the fertilized egg, which lies immediately below. The chorioallantoic membrane (CAM) of fertilized and incubated hen eggs provides a suitable model for membranes with an intact and functional vascular system. The CAM has no nerve fibers in the early stages of development and is, thus, regarded as being insensitive to pain.

In this model the cumulative irritation score of the test item was 0.00.

Applicant's summary and conclusion

Interpretation of results:
other: Category 2 (irritant) based on EU GHS criteria
Conclusions:
According to Regulation (EC) No 1272/2008 the test material should be regarded as an irritant to the skin.
Executive summary:

The substance was tested for skin irritation in an Acute Dermal Irritation / Corrosion test according to OECD Guideline 404 following GLP.

Purpose

The purpose of this assay was to identify the skin irritation/corrosion potential of the test material when applied to the intact skin of previously shaven rabbits for a 4 hours period under semiocclusive conditions.

This study should provide a rational basis for risk assessment to the irritating potential of the test item in man.

Study Design

To test for primary skin irritation, 0.5 g of the test material was mixed with some drops of liquid paraffin to ensure good contact with the skin. Afterwards the test material was spread onto 6 cm2 patches and applied to the intact skin of previously shaven rabbits for a 4 hours period under semiocclusive conditions. The study was started as an initial test with one animal. This animal showed signs of irritation (well defined erythema, edema, brittle skin, and scales) and no more animals were treated. The first examination of the treated skin sites followed 1 hour after removal of the patches. Thereafter, examinations were performed daily for further 21 days.

Results

Only one rabbit was used for the study. No signs of pain were observed after administration. Under the conditions of the present study erythema (scores 1 to 3) were observed from day 1 up to day 5 and edema (scores 1 to 4) were observed from day 2 up to day 9 of the study. Furthermore brittle skin from day 6 up to day 9 and small scales from day 10 up to day 17 of the study were seen at the site of application. From day 18 up to the end of the experimental part increased growth of hair was observed.

Conclusion

The test material caused irritative effects at the site of application. According to Regulation (EC) No 1272/2008 the test material should be regarded as an irritant to the skin.