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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 performed Between 31 August 2011 and 09 September 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2011
Report Date:
2012

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
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: solid
Details on test material:
Sponsor's identification: Carbohydrazide
Identifier : TIS I0352
CAS number : 497-18-7
Description : white solid
Batch number : OJ24-21M
Date received : 04 April 2011
Expiry date : 24 January 2013
Storage conditions: room temperature in the dark, over silica gel

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
Three New Zealand White (Hsdlf:NZW) strain rabbits were supplied by Harlan Laboratories UK Ltd. , UK. At the start of the study the animals weighed 2.37 to 2.79 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 (2930 Teklad Global Certified Rabbit diet) was allowed throughout 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.

Test system

Type of coverage:
semiocclusive
Preparation of test site:
clipped
Vehicle:
other: Test item was moistened with distilled water.
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:
3 minutes, 1 hour and 4 hours for initial animal.
4 hours for subsequent animals.
Observation period:
72 hours
Number of animals:
3
Details on study design:
MEASUREMENT OF PH:
The pH of the test item was determined prior to commencement of the study and foud to be as follows:
10% w/w aqueous preparation of the test item: 8.3 (immediately and after 10 minutes).

PROCEDURE:
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 0.5 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. 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 item was removed by gentle swabbing with cotton wool soaked in distilled water.

After consideration of the skin reactions produced in the first animal, an additional two animals were treated with 0.5 g of test item, moistened sufficiently 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.

SCORING SYSTEM:
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 according to the following scale:

EVALUATION OF SKIN REACTIONS
Erythema and Eschar Formation
No erythema: 0
Very slight erythema (barely perceptible): 1
Well-defined erythema: 2
Moderate to severe erythema: 3
Severe erythema (beef redness) to eschar formation preventing grading of erythema.: 4

Oedema Formation
 No oedema: 0
Very slight oedema (barely perceptible): 1
Slight oedema (edges of area well-defined by definite raising): 2
Moderate oedema (raised approximately 1 millimetre): 3
Severe oedema (raised more than 1 millimetre and extending beyond the area of exposure): 4

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

Individual bodyweights 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
Basis:
mean
Remarks:
(Animal 70904 - male)
Time point:
other: Mean of scores at 24, 48 and 72 hours
Score:
0.33
Max. score:
4
Reversibility:
fully reversible within: 48 hours
Remarks on result:
other: Results from 4-Hour Exposure
Irritation parameter:
erythema score
Basis:
mean
Remarks:
(Animal 70926 - male)
Time point:
other: Mean of scores at 24, 48 and 72 hours
Score:
0
Max. score:
4
Reversibility:
fully reversible within: 24 hours
Remarks on result:
other: Results from 4-Hour exposure.
Irritation parameter:
erythema score
Basis:
mean
Remarks:
(Animal 70927 - male)
Time point:
other: Mean of scores at 24, 48 and 72 hours
Score:
0
Max. score:
4
Reversibility:
fully reversible within: 24 hours
Remarks on result:
other: Results from 4-Hour exposure
Irritation parameter:
edema score
Basis:
mean
Remarks:
(Animal 70904 - male)
Time point:
other: Mean of scores at 24, 48 and 72 hours
Score:
0.33
Max. score:
4
Reversibility:
fully reversible within: 48 hours
Remarks on result:
other: Results from 4-Hour exposure
Irritation parameter:
edema score
Basis:
mean
Remarks:
(Animal 70926 - male)
Time point:
other: Mean of scores at 24, 48 and 72 hours
Score:
0
Max. score:
4
Remarks on result:
other: Results from 4-Hour exposure
Irritation parameter:
edema score
Basis:
mean
Remarks:
(Animal 70927 - male)
Time point:
other: Mean of scores at 24, 48 and 72 hours
Score:
0
Max. score:
4
Remarks on result:
other: Results from 4-Hour exposure
Irritant / corrosive response data:
Skin Reactions:
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 Exposur Period :
The individual scores for erythema/eschar and oedema are given in Table 2.
Very slight erythema and very slight oedema were noted at one treated skin site with very slight erythema noted at two treated skin sites one hour after patch removal. Very slight erythema and very slight oedema were noted at one treated skin site at the 24‑hour observation.
Two treated skin sites appeared normal at the 24‑hour observation and the remaining treated skin site appeared normal at the 48-Hour observation. 
Other effects:
Bodyweight:
Individual bodyweights and bodyweight changes are given in Table 3.
All animals showed expected gain in bodyweight during the study.

Any other information on results incl. tables

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

Skin Reaction

Observation Time
(following patch removal)

Individual Scores - Rabbit Number and Sex

70904Male

3-Minute Exposure

1-Hour Exposure

Erythema/Eschar Formation

Immediately

0

0

1 Hour

0

0

24 Hours

0

0

48 Hours

0

0

72 Hours

0

0

Oedema Formation

Immediately

0

0

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
(following patch removal)

Individual Scores – Rabbit Number and Sex

Total

70904Male

70926Male

70927Male

Erythema/Eschar Formation

Immediately

0

0

0

(0 )

1 Hour

1

1

1

( 3 )

24 Hours

1

0

0

1

48 Hours

0

0

0

( 0 )

72 Hours

0

0

0

0

Oedema Formation

Immediately

0

0

0

( 0 )

1 Hour

1

0

0

( 1 )

24 Hours

1

0

0

1

48 Hours

0

0

0

( 0 )

72 Hours

0

0

0

0

Sum of 24 and 72-hour Readings (S)     :          2

Primary Irritation Index (S/6)                  :          2/6 = 0.3

Classification                                       :          MILD IRRITANT


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

Table 3              Individual Bodyweights and Bodyweight Changes

Rabbit Number
and Sex

Individual Bodyweight (kg)

Bodyweight Change (kg)

Day 0

Day 3

70904Male

2.49

2.53

0.04

70926Male

2.37

2.43

0.06

70927Male

2.79

2.80

0.01

Applicant's summary and conclusion

Interpretation of results:
not classified
Remarks:
Migrated information mild irritant Criteria used for interpretation of results: EU
Conclusions:
The test item produced a primary irritation index of 0.3 and was classified as a mild irritant to rabbit skin according to the Draize classification scheme. No corrosive effects were noted.
The test item did not meet the criteria for classification according to the Classification, Labelling and Packaging Regulation or the Globally Harmonised Classification System.
Executive summary:

Introduction.

The study was performed to assess the irritancy potential of the test item to the skin of the New Zealand White rabbit. The method was designed to be compatible with the following:

- OECD Guidelines for the Testing of Chemicals No. 404 "Acute Dermal Irritation/Corrosion" (adopted 24 April 2002)

- Method B4 Acute Toxicity (Skin Irritation) of Commission Regulation (EC) No. 440/2008

Results.

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

A single 4-hour, semi-occluded application of the test item to the intact skin of three rabbits produced very slight erythema and very slight oedema. Two treated skin sites appeared normal at the 24-hour observation and the remaining treated skin site appeared normal at the 48-Hour observation. No corrosive effects were noted.

Conclusion.

The test item produced a primary irritation index of 0.3 and was classified as a mild irritant to rabbit skin according to the Draize classification scheme.

The test item did not meet the criteria for classification according to the Classification, Labelling and Packaging Regulation or the Globally Harmonised Classification System.