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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:
The study was conducted between 15 December 2015 and 18 December 2015
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2016
Report Date:
2016

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)
Deviations:
no
Principles of method if other than guideline:
None
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
None
Specific details on test material used for the study:
None

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
Animals and Animal Husbandry
Two New Zealand White (Hsdlf:NZW) strain rabbits were supplied by Envigo RMS (UK) Limited, Leicestershire, UK. At the start of the study the animals weighed 2.57 or 3.52 kg and were 12 to 20 weeks old. After an acclimatization period of at least 5 days each animal was given a number unique within the study which was written with a black indelible marker pen on the inner surface of the ear and on the cage label.

The animals were individually housed in suspended cages. Free access to mains drinking water and food (2930C Teklad Global Rabbit diet supplied by Envigo RMS (UK) Limited, Oxon, UK) was allowed throughout the study. The diet and drinking water were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

The temperature and relative humidity were set to achieve limits of 17 to 23 °C and 30 to 70% respectively. The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give 12 hours continuous light and 12 hours darkness.

The animals were provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

Justification
The rabbit is the preferred species of choice as historically used for irritation studies and is specified in the appropriate test guidelines. The number of animals used was the minimum required to achieve the objectives of the study. Testing was conducted in two animals and the response in those animals was such that exposure of a third animal would not affect classification of the test item, no further testing was needed.

Test system

Type of coverage:
semiocclusive
Preparation of test site:
clipped
Vehicle:
unchanged (no vehicle)
Controls:
no
Amount / concentration applied:
0.5 g of the test item moistened sufficiently with 0.5 mL of distilled water.
Duration of treatment / exposure:
4 hours
Observation period:
72 hours
Number of animals:
Two
Details on study design:
Procedure
On the day before the test two rabbits were clipped free of fur from the dorsal/flank area using veterinary clippers. Only animals with a healthy intact epidermis by gross observation were selected for the study.

On the day of the test a suitable test site was selected on the back of each rabbit. At each test site a quantity of 0.5 g of the test item, moistened sufficiently with 0.5 mL of distilled water, was introduced under a 2.5 cm x 2.5 cm cotton gauze patch. The patch was secured in position with a strip of surgical adhesive tape. To prevent the animals interfering with the patches, the trunk of each rabbit was wrapped in an elasticated corset and the animals were returned to their cages for the duration of the exposure period.

Four hours after application the corset and patches were removed from each animal and any residual test item removed by gentle swabbing with cotton wool soaked in distilled water.

Immediately following removal of the patches and approximately 1, 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored.

Any other skin reactions and clinical signs of toxicity, if present, were also recorded.

Individual body weights were recorded on Day 0 (the day of dosing) and at the end of the observation period.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Remarks:
75285 Male
Basis:
mean
Time point:
other: 24, 48 and 72 hours
Score:
0
Max. score:
4
Reversibility:
other: Not applicable
Remarks on result:
other: No corrosive or irritant effects were observed
Irritation parameter:
erythema score
Remarks:
75286 Male
Basis:
mean
Time point:
other: 24, 48 and 72 hours
Score:
0
Max. score:
4
Reversibility:
other: Not applicable
Remarks on result:
other: No corrosive or irritant effects were observed
Irritation parameter:
edema score
Remarks:
75285 Male
Basis:
mean
Time point:
other: 24, 48 and 72 hours
Score:
0
Max. score:
4
Reversibility:
other: Not applicable
Remarks on result:
other: No corrosive or irritant effects were observed
Irritation parameter:
edema score
Remarks:
75286 Male
Basis:
mean
Time point:
other: 24, 48 and 72 hours
Score:
0
Max. score:
4
Reversibility:
other: Not applicable
Remarks on result:
other: No corrosive or irritant effects were observed
Irritant / corrosive response data:
Dark blue colored staining, not preventing evaluation of skin responses, was noted at both treated skin sites at all observations. No evidence of skin irritation was noted during the study.
Other effects:
Body Weight
Both animals showed expected gain in body weight during the study.

Any other information on results incl. tables

Individual Skin Reactions

Skin Reaction

Observation Time
(following patch removal)

Individual Scores

Total

Rabbit Number and Sex

75285Male

75286Male

Erythema/Eschar Formation

Immediately

0STA

0STA

(0 )

1 Hour

0STA

0STA

( 0 )

24 Hours

0STA

0STA

0

48 Hours

0STA

0STA

( 0 )

72 Hours

0STA

0STA

0

Edema Formation

Immediately

0

0

( 0 )

1 Hour

0

0

( 0 )

24 Hours

0

0

0

48 Hours

0

0

( 0 )

72 Hours

0

0

0

Sum of 24 and 72‑Hour Readings (S) :        0

Primary Irritation Index (S/4)              :        0/4 = 0.0

Classification                                       :        NON‑IRRITANT

(   ) =    Total values not used for calculation of primary irritation index

STA =    Dark blue colored staining

Individual Body Weights and Body Weight Change

Rabbit Number
and Sex

Individual Body Weight (kg)

Body Weight Change (kg)

Day 0

Day 3

75285
Male

2.57

2.60

0.03

75286
Male

3.52

3.64

0.12

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test item can be considered to be non-irritant.
Executive summary:

A skin irritation study was conducted according to OECD Guideline 404 and EU Method B.4. Two New Zealand White rabbits were exposed to a single 4‑hour, semi‑occluded application of the test item to the intact skin. There was no evidence of skin irritation recorded. The test item produced a primary irritation index of 0. Hence the test item can be considered to be non-irritant.