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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 performed between 14 February 2008 and 29 February 2008.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 404 (Acute Dermal Irritation / Corrosion)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
Date of inspection: 15-09-2009 Date of Signature: 26-11-2009

Test material

Constituent 1
Reference substance name:
1,3-Cyclohexanedione
IUPAC Name:
1,3-Cyclohexanedione
Details on test material:
Sponsor's identification : 1,3-Cyclohexanedione
Description : pale yellow powder
Batch number : 184731073312
Date received : 14 January 2008
Storage condition : room temperature in the dark

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:

Animals and Animal Husbandry
Three New Zealand White rabbits were supplied by Harlan France SARL, 03800 GANNAT, France.

At the start of the study the animals were in the weight range of 2.0 to 3.5 kg and were twelve to twenty weeks old.

After an acclimatisation period of at least five 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 (Certified Rabbit Diet) 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. Any occasional deviations from these targets were considered not to have affected the purpose or integrity of the study.

The rate of air exchange was at least fifteen changes per hour and the lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve 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.

Test system

Type of coverage:
semiocclusive
Preparation of test site:
shaved
Vehicle:
other: At each test site a quantity of 0.5g of the test material, moistened with 0.5 ml of distilled water.
Controls:
no
Amount / concentration applied:

On the day before the test each rabbit was 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.

One rabbit was initially treated.

Three suitable sites were selected on the back of the rabbit.

At each test site a quantity of 0.5g of the test material, moistened with 0.5 ml of distilled water, was introduced under a 2.5 cm x 2.5 cm cotton gauze patch and placed in position on the shorn skin.

Duration of treatment / exposure:
4 hours
Observation period:
Approximately one hour following the removal of the patches, and 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored.

Number of animals:
3
Details on study design:
On the day before the test each rabbit was 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.

One rabbit was initially treated.

Three suitable sites were selected on the back of the rabbit. At each test site a quantity of 0.5g of the test material, moistened with 0.5 ml of distilled water, was introduced under a 2.5 cm x 2.5 cm cotton gauze patch and placed in position on the shorn skin. Each patch was secured in position with a strip of surgical adhesive tape.
To prevent the animal interfering with the patches, the trunk of the rabbit was wrapped in an elasticated corset for the duration of the exposure period.
One patch was removed at each of three time points: 3 minutes, 1 hour and 4 hours after application.

Any residual test material was removed by gentle swabbing with cotton wool soaked in distilled water.

After consideration of the skin reactions produced in the first animal, two additional animals were treated with 0.5 g of test material moistened with 0.5 ml of distilled water. One patch was applied to the back of each rabbit, and was allowed to remain in contact with the skin for a period of four hours.

Approximately one hour following the removal of the patches, and 24, 48 and 72 hours later, the test sites were examined for evidence of primary irritation and scored according to the following scale:


SCORING SYSTEM:
Please see table "EVALUATION OF SKIN REACTIONS"

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Basis:
animal: 67222 male
Time point:
other: Mean score at 24, 48 and 72 hours
Score:
0.33
Max. score:
1
Reversibility:
fully reversible within: 48 Hours
Irritation parameter:
erythema score
Basis:
animal: 67239 Male
Time point:
other: Mean at 24, 48 and 72 hours
Score:
0.33
Max. score:
1
Reversibility:
fully reversible within: 48 Hours
Irritation parameter:
erythema score
Basis:
animal: 67240 male
Time point:
other: mean at 24, 48 and 72 hours
Score:
0.33
Max. score:
1
Reversibility:
fully reversible within: 48 Hours
Irritation parameter:
edema score
Basis:
animal: 67222 male
Time point:
other: mean of 24, 48 and 72 hours
Score:
0
Max. score:
0
Reversibility:
other: No evidence of skin irritation
Irritation parameter:
edema score
Basis:
animal: 67239 male
Time point:
other: mean at 24, 48 and 72 hours
Score:
0
Max. score:
0
Reversibility:
other: No evidence of skin irritation
Irritation parameter:
edema score
Basis:
animal: 67240 male
Time point:
other: Mean at 24, 48 and 72 hours
Score:
0
Max. score:
0
Reversibility:
other: No evidence of skin irritation
Irritant / corrosive response data:
3-Minute Exposure Period
The individual scores for erythema/eschar and oedema are given in Table 1.

No evidence of skin irritation was noted during the study.

1-Hour Exposure Period
The individual scores for erythema/eschar and oedema are given in Table 1.

No evidence of skin irritation was noted during the study.

4-Hour Exposure Period
The individual scores for erythema/eschar and oedema are given in Table 2.

Very slight erythema was noted at all treated skin sites at the 24-hour observation. All treated skin sites appeared normal at the 48-hour observation.
Other effects:
None

Any other information on results incl. tables

Interpretation of Results

Calculation of Primary Irritation Index and Grading of Irritancy Potential Using the Draize Scheme

The scores for erythema and oedema at the 24 and 72-hour readings were totalled for the three test rabbits (12 values) and this total was divided by six to give the primary irritation index of the test material. The test material was classified according to the following scheme devised by Draize J H (1959) "Dermal Toxicity" In: Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics. Association of Food and Drug Officials of the United States, Austin, Texas, p.46-59:

Primary Irritation Index

Classification of Irritancy

0

Non-irritant

> 0 to 2

Mild irritant

> 2 to 5

Moderate irritant

> 5 to 8

Severe irritant

If irreversible alteration of the dermal tissue is noted in any rabbit, as judged by the Study Director, which include ulceration and clear necrosis or signs of scar tissue, the test material is classified as corrosive to rabbit skin. Classification according to Draize may, therefore, not be applicable.

Table 1               Individual Skin Reactions Following 3-Minute and 1-Hour Exposures

Skin Reaction

Observation Time

Individual Scores - Rabbit Number and Sex

67222 Male

3-Minute Exposure

1-Hour Exposure

Erythema/Eschar Formation

1 Hour

0

0

24 Hours

0

0

48 Hours

0

0

72 Hours

0

0

Oedema Formation

1 Hour

0

0

24 Hours

0

0

48 Hours

0

0

72 Hours

0

0

 


Table 2               Individual Skin Reactions Following 4-Hour Exposure

Skin Reaction

Observation Time

Individual Scores – Rabbit Number and Sex

Total

67222 Male

67239 Male

67240 Male

Erythema/Eschar Formation

1 Hour

0

0

0

(0 )

24 Hours

1

1

1

3

48 Hours

0

0

0

( 0 )

72 Hours

0

0

0

0

Oedema Formation

1 Hour

0

0

0

( 0 )

24 Hours

0

0

0

0

48 Hours

0

0

0

( 0 )

72 Hours

0

0

0

0

Sum of 24 and 72-hour Readings (S)             :              3

Primary Irritation Index (S/6)                          :              3/6 = 0.5

Classification                                                      :              MILD IRRITANT


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

Applicant's summary and conclusion

Interpretation of results:
other: Mild irritant to rabbit skin.
Remarks:
Criteria used for interpretation of results: other: Draize classification scheme.
Conclusions:
The test material produced a primary irritation index of 0.5 and was classified as a mild irritant to rabbit skin according to the Draize classification scheme.
Executive summary:

Introduction. 

The study was performed to assess the irritancy potential of the test material to the skin of the New Zealand White rabbit. The method was designed to meet the requirements of the following:

§        OECD Guidelines for the Testing of Chemicals No. 404 “Acute Dermal Irritation/Corrosion” (adopted)

§        Method B4 Acute Toxicity (Skin Irritation) of Commission Directive 2004/73/EC

Initial considerations. 

Available information indicated that the test material had the potential to produce severe irritation/corrosion and to confirm this initial assessment an ex vivo pre-screen test, the Transcutaneous Electrical Resistance (TER) Assay, was performed. The results of the pre-screen test indicated that the test material was considered not to be corrosive to the skin and thein vivo study was performed. The results of the TER Assay are given in Appendix 1.

Results. 

3-minute and 1-hour semi-occluded applications of the test material to the intact skin of one rabbit produced no evidence of skin irritation.

A single 4-hour, semi-occluded application of the test material to the intact skin of three rabbits produced very slight erythema. All treated skin sites appeared normal at the 48-hour observation. No corrosive effects were noted.

Conclusion.

The test material produced a primary irritation index of 0.5 and was classified as a mild irritant to rabbit skin according to the Draize classification scheme.