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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:
30 December 2009 - ................................
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Compliant to GLP and testing guideline; adequate coherence between data, comments and conclusions.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
temperature and humidity sometimes outside of the target ranges; animals were more than 2 to 4 months old; body weight of animal No. 194 was higher than 3.5 kg (3.6 kg); animals were sacrificed several days after the end of the observation period
Qualifier:
according to
Guideline:
EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)
Deviations:
yes
Remarks:
idem above
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Breeder: Charles River Laboratories (Châtillon-sur-Chalaronne, France)
- Age at study initiation: 2 to 5 months old
- Weight at study initiation: 3.387 +/- 0.218 kg
- Housing: individual Pajon cages
- Diet (e.g. ad libitum): free access to 110 pelleted diet
- Water (e.g. ad libitum): drinking water filtered by a FG Millipore membrane, provided ad libitum
- Acclimation period: at least 5 days before the beginning of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 +/- 3°C
- Humidity (%): 30 to 70%
- Air changes (per hr): 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/ 12 h (7:00 - 19:00)

IN-LIFE DATES: From: 23 December 2009 To: 02 February 2010

Test system

Type of coverage:
semiocclusive
Preparation of test site:
other: clipped
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied: 0.5 mL
Duration of treatment / exposure:
3 minutes, 1 hour, 4 hours.
Observation period:
1 hour, 24, 48 and 72 hours after removal of the dressing, and then daily until the end of the observation period.
Number of animals:
Three males.
Details on study design:
TEST SITE
- Area of exposure: anterior left flank: application for 3 minutes; anterior right flank: application for 1 hour; or the posterior right flank:
application for 4 hours of the animals.
- coverage: 6 cm2
- Type of wrap if used: gauze pad was held in contact with the skin by means of an adhesive hypoallergenic aerated semi-occlusive dressing and a restraining bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): dry cotton pad
- Time after start of exposure: at removal of each dressing.

SCORING SYSTEM:
Dermal irritation was evaluated for each animal according to the following scoring scale:

Erythema and eschar formation:
no erythema 0
very slight erythema (barely perceptible) 1
well-defined erythema 2
moderate to severe erythema 3
severe erythema (beet redness) to slight eschar formation (injuries in depth) 4

Edema formation
no edema 0
very slight edema (barely perceptible) 1
slight edema (edges of area well-defined by definite raising) 2
moderate edema (raised approximately 1 millimeter) 3
severe edema (raised more than 1 millimeter and extending beyond area
of exposure) 4

Any other lesions were noted.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
animal #1
Time point:
other: 24 h, 48 h, 72 h
Score:
3
Max. score:
3
Reversibility:
not reversible
Remarks on result:
other: mean score
Irritation parameter:
erythema score
Basis:
animal #2
Time point:
other: 24 h, 48 h, 72 h
Score:
3
Max. score:
3
Reversibility:
not reversible
Remarks on result:
other: mean score
Irritation parameter:
erythema score
Basis:
animal #3
Time point:
other: 24 h, 48 h, 72 h
Score:
3
Max. score:
3
Reversibility:
not reversible
Remarks on result:
other: mean score
Irritation parameter:
edema score
Basis:
animal #1
Time point:
other: 24 h, 48 h, 72 h
Score:
0
Max. score:
0
Remarks on result:
other: mean score
Irritation parameter:
edema score
Basis:
animal #2
Time point:
other: 24 h, 48 h, 72 h
Score:
0
Max. score:
0
Remarks on result:
other: mean score
Irritation parameter:
edema score
Basis:
animal #3
Time point:
other: 24 h, 48 h, 72 h
Score:
0
Max. score:
0
Remarks on result:
other: mean score
Irritant / corrosive response data:
After a 3-minute exposure (animal No. 194)
A very slight to moderate erythema (grades 1 to 3) was observed from day 1 until day 11.
Dryness of the skin was noted from day 6 until day 15.

After a 1-hour exposure (animal No. 194)
A very slight or well-defined erythema (grade 1 or 2) was observed from day 1 until day 11.
Dryness of the skin was noted from day 7 until day 14.

After a 4-hour exposure (three animals)
A well-defined or moderate erythema (grade 2 or 3) was noted all over the observation period in 2/3 animals (Nos. 194 and 199), associated with a very slight edema (grade 1) on days 6 and 7 in one of them (No. 194).
In the third animal (No. 198), very slight to moderate erythema (grades 1 to 3) was noted all over the observation period, except on days 8 and 9 for which an important dryness of the skin masked the evaluation of erythema.
Dryness of the skin was recorded from day 5 or 7 until day 13 or 15 in all animals.
Mean scores over 24, 48 and 72 hours for each animal were 3.0, 3.0 and 3.0 for erythema and 0.0, 0.0 and 0.0 for edema.

Applicant's summary and conclusion

Interpretation of results:
Category 2 (irritant) based on GHS criteria
Conclusions:
Tert-Dodecylmercaptan was irritating when applied topically to rabbits.
Executive summary:

In a study performed according to OECD guideline #404 and GLP, t-Dodecyl mercaptan was first applied for periods of 3 minutes, 1 hour and 4 hours to a single male New Zealand White rabbit. Since the test item was neither severely irritant nor corrosive on this first animal, it was then applied sequentially for 4 hours to two other animals. A single dose of 0.5 mL of the undiluted test item was applied to the closely-clipped skin of one flank. The test item was held in contact with the skin by means of a semi-occlusive dressing. Cutaneous reactions were observed approximately 1 hour, 24, 48 and 72 hours after removal of the dressing, and then daily until the end of the observation period. The mean values of the scores for erythema and edema were calculated for each animal.

After a 3-minute exposure (one animal), a very slight to moderate erythema was observed from day 1 until day 11. Dryness of the skin was noted from day 6 until day 15. After a 1-hour exposure (one animal), a very slight or well-defined erythema was observed from day 1 until day 11. Dryness of the skin was noted from day 7 until day 14. After a 4-hour exposure (three animals), a well-defined or moderate erythema was noted all over the observation period in 2/3 animals, associated with a very slight edema on days 6 and 7 in one of them. In the third animal, very slight to moderate erythema was noted all over the observation period, excepted on days 8 and 9 for which an important dryness of the skin masked the evaluation of erythema. Dryness of the skin was recorded from day 5 or 7 until day 13 or 15 in all animals. Mean scores over 24, 48 and 72 hours for each animal were 3.0, 3.0 and 3.0 for erythema and 0.0, 0.0 and 0.0 for edema. Under these experimental conditions, tert-dodecylmercaptan was irritating when applied topically to rabbits.