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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Justification for type of information:
Data is from experimental study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: as mentioned below
Principles of method if other than guideline:
The test is designed to investigate the irritation effects of substances when applied once to the intact skin under a semi-occlusive dressing.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline
Details on test material:
- Name of test material: 2, 2, 2-trichloro-1-phenylethyl acetate
- Molecular formula: C10H9Cl3O2
- Molecular weight: 267.54
- Substance type: Organic
- Physical state: Solid

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
- Age at study initiation: 9-12 weeks

Test system

Type of coverage:
semiocclusive
Preparation of test site:
clipped
Vehicle:
unchanged (no vehicle)
Controls:
yes
Amount / concentration applied:
0.5 ml of each test and std. solution (0.2 gm for solid samples)
Duration of treatment / exposure:
7 days
Observation period:
24,48 and 72 hours after treatment, and occasionally up to 7 days
Number of animals:
8 animals
Details on study design:
TEST SITE
- Area of exposure: -clipped dorsum of each rabbit
- Type of wrap if used:Occlusive patches are prepared by attaching a piece of thin flexible polythene (3cm x 3cm) to a piece of zinc oxide plaster 9cm x 2.5cm. A 2.5 cm square of cotton gauze (8 ply folded in two) is laid on the polythene such that the edges of the pad are attached to the zinc oxide plaster

REMOVAL OF TEST SUBSTANCE
- Washing (if done): treated areas were wiped clean of excess material.
- Time after start of exposure: sites were evaluated at 24, 48 and 72 hours after treatment, and occasionally up to 7 days after treatment

SCORING SYSTEM: The wilcoxon matched - pairs signed ranks test, which consideres the size and direction of differences between reactions is used to test the significance of differences between pairs of treatment groups.

other: The whole dorsal surface is clipped 3-4 days before the test is due to start and animals in the telogen phase of hair growth are selected. Test solutions (0.5 ml) are applied to a dry patch. Test solids are applied to a moistened patch. Aerosol preparations are applied directly to the skin with two 1 second burst and the patches are saturated with spray which acts as a reservoir.

The patches are firmly attached to ensure good contact between the skin and test substance. The animals are immobilised in a canvas body sleeve for 4 hours after application of the patch. When the patches are removed, the treatment sites are wiped clean of excess material. The position of treatment sites are randomised.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
overall irritation score
Remarks:
Test chemical
Basis:
mean
Time point:
24/48/72 h
Score:
11
Reversibility:
fully reversible within: 72 hours
Remarks on result:
other: By 48 and 72 hours there were no visible macroscopic changes.
Irritation parameter:
other: Mean Score per site
Remarks:
test chemical
Basis:
mean
Time point:
other: 4/24/48/72 h
Reversibility:
fully reversible within: 72 hours
Remarks on result:
no indication of irritation
Irritation parameter:
other: Mean score per site per day
Basis:
mean
Time point:
other: 4/24/48/72 h
Score:
0.34
Reversibility:
fully reversible within: 72 hours
Remarks on result:
no indication of irritation
Irritant / corrosive response data:
A single application of the test chemical produced marginal erythema in a few animals and marginal edema in one animal at 24 hours. By 48 and 72 hours there were no visible macroscopic changes.

Any other information on results incl. tables

Table 2: Daily microscopic assessment of irritation reaction of Test Chemical

Rabbit

Treatment site no.

4 Hours

24 Hours

48 Hours

72 Hours

Total

Total score

No.

Wt (Kg)

 

er

oe

cr

sc

 

 

er

oe

cr

sc

 

 

er

oe

cr

sc

 

 

er

oe

cr

sc

 

 

er

oe

cr

sc

 

 

 

1144

 

2

a

a

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

1

1

0

0

 

 

2

1145

 

3

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

0

0

0

0

 

 

0

1146

 

4

a

a

-

-

 

 

a

a

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

2

2

0

0

 

 

4

1147

 

5

a

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

1

0

0

0

 

 

1

1092

 

6

-

-

-

-

 

 

a

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

1

0

0

0

 

 

1

1101

 

1

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

0

0

0

0

 

 

0

1163

 

1

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

0

0

0

0

 

 

0

1164

 

4

a

b

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

-

-

-

-

 

 

1

2

0

0

 

 

3

Overall irritation score

11

Mean score per site

1.38

Mean score per site per day

0.34

 

Note:

er

Erythema

oe

Oedema

cr

Cracking

sc

Scaling

sb

Scabbing

ex

Exudate

hae

Haemorrahage

 

Reaction grades and scores:

Marginal/very slight

1

Slight

2

Fairly distinct

3

Quite distinct

4

Becoming well developed

6

Well developed

8

Becoming severe

10

Severe

12

Table 3: Total Irritation Scores

Rabbit number

Treatment groups

C

B

D

A

F

E

1144

0

2

1

26

21

27

1145

3

0

1

38

45

40

1146

1

4

2

34

26

33

1147

1

1

2

25

31

31

1092

0

1

2

18

30

31

1101

1

0

9

21

24

22

1163

0

0

3

26

44

39

1164

4

3

3

25

15

19

Overall irritation score

10

11

23

213

236

242

Mean score per site

1.25

1.38

2.88

26.63

29.5

30.25

Mean score per site per day

0.31

0.34

0.72

6.66

7.38

7.56

Mean Irritation Ranking

1.75

1.81

2.44

4.63

5.06

5.31

Reaction Grades and Score

a- Marginal/very slight = 1

b- Slight = 2

c- Fairly distinct = 3

d- Quite distinct = 4         

e- Becoming well developed = 6

f- Well developed = 8

g- becoming severe = 10

h- severe = 12

Applicant's summary and conclusion

Interpretation of results:
other: Not Irritating
Conclusions:
A single application of the test chemical produced marginal erythema in a few animals and marginal edema in one animal at 24 hours. By 48 and 72 hours there were no visible macroscopic changes. The mean score per site per day for test chemical was calculated to be 0.34. Based on the scores and observations, the test material can be considered as not irritating to New Zealand White rabbit skin.
Executive summary:

The test is designed to investigate the irritation effects of when applied once to the intact skin under a semi-occlusive dressing. Eight New Zealand White rabbits were used for the study.

in this test, the dorsal surface was clipped 3 -4 days before the test was due to start. Occlusive patches were prepared by attaching a piece of thin flexible polythene (3*3 cm) to a piece of zinc oxide plaster 9cm*2.5cm. A 2.5 cm square of cotton gauze was laid on the polythene such that the edges of the pad are attached to the zinc oxide plaster. 0.2 gm of undiluted test chemical on a patch dampened with Diethyl Phthalate and 0.5ml of the standards for comparison were applied to the clipped dorsum of rabbits for 4 hours under individual semi-occlusive patches. Bromostyrene, Coumarin, Diethyl phthalate, Cyclamen aldehyde and Geraniol were used as standards for comparison.

Four hours after exposure, the patches were removed and the test sites were wiped cleaned of the excess test material. The sites were scored for erythema, edema, cracking and scaling and any other feature using an 8 point grading scale ranging from "a" (very slight) to "h"(very severe). At the end of the test the reaction grades which were used to calculate the total irritation score per site, a mean irritation score per site per day for each treatment group.

A single application of the test chemical produced marginal erythema in a few animals and marginal edema in one animal at 24 hours. By 48 and 72 hours there were no visible macroscopic changes. The response was similar to that produced by Coumarin and Diethyl phthalate, but considerably less than that produced by Geraniol and Cyclamen aldehyde.

The mean score per site per day for test chemical was calculated to be 0.34.

Based on the scores and observations, the test material can be considered as not irritating to New Zealand White rabbit skin.