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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
08 June - 26 July 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Two independent tests were run which are combined in the present record.

Data source

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

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: OECD Guideline 439; In vitro skin irritation: Reconstructed human epidermis method
GLP compliance:
yes (incl. certificate)

Test material

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

Test animals

Species:
other: EPISKIN human epidermis skin constructs.
Strain:
other: Commercial test kit
Details on test animals and environmental conditions:
Not applicable

Test system

Type of coverage:
not specified
Preparation of test site:
not specified
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 µL
- Concentration (if solution): 100%

Duration of treatment / exposure:
15 minutes
Observation period:
not applicable
Number of animals:
not applicable
Details on study design:
See any other information below

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
other:
Run / experiment:
1
Value:
59.1
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
other:
Run / experiment:
2
Value:
41.6
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
other:
Run / experiment:
3
Value:
45.5
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
other:
Run / experiment:
Mean of 3
Value:
48.8
Remarks on result:
other:
Remarks:
Borderline result: 45-55%, but substance is considered an irritant
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
4
Value:
58.2
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
5
Value:
57.2
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
6
Value:
49.2
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
mean of 3
Value:
55
Remarks on result:
other:
Remarks:
Less irritancy is seen compared to the first test but final conclusion is that the substance is an irritant

Any other information on results incl. tables

Table 1 EPISKIN Results Repeat Study (key study)

 

Sample

Tissue viability as percentage of mean OD negative

control

Prediction MTT endpoint

 

Replicate Tissues

Mean ± SD

 

a

b

c

 

 

Negative Control

101.6

99.3

99.1

100.0 ± 1.4

Non-irritant

Positive control

19.3

28.4

12.1

19.9 ± 8.2

Irritant

IFF TM 09 -221

59.1

41.6

45.5

48.8 ± 9.2

Irritant

As the mean tissue viability was less than 50% of the negative control value in the repeat study (48.8% +/- 9.2%), it was decided to classify the test-substance conservatively as Irritant R38 (EU DSD) / Irritant H315 (EU CLP) and not to run another repeat study.

Table 2 EPISKIN Results Original Study

 

Sample

Tissue viability as percentage of mean OD negative

control

Prediction MTT endpoint

 

Replicate Tissues

Mean ± SD

 

a

b

c

 

 

Negative Control

114.5

87.0

98.5

100.0 ± 13.8

Not applicable

Positive control

10.8

11.3

13.9

12.0 ± 1.7

Irritant

IFF TM 09 -221

58.2

57.2

49.5

55.0 ± 4.8

Non-irritant

As the tissue viability of 55.0% was a borderline result in the range 45-55%, it was proposed to repeat the test in a further study, although the OECD guideline does not have an absolute requirement for a repeat test.

Methodology

The mean Optical Density (OD) for the 6 replicate blanks was subtracted from the individual substance and control tissues OD.

The viability of each tissue was expressed as a percentage of the mean negative control value.

Assay acceptance criteria

The OD from the negative control tissue in the MTT assay is an indicator of tissue viability after the shipping and storage procedure and under the specific conditions of the assay. The mean absorbance of the triplicate negative control values should be >=0.6 and the Standard Deviation (SD) value of the % viability should be ≤18. The OD of the positive control is an indicator of the sensitivity of the tissues. The mean viability should be ≤30% of the negative control and the SD ≤18.

Data interpretation - Prediction model

If the mean tissue viability was less than 50% of the negative control value, the sample was classed as Irritant

If the mean tissue viability was greater than 50% of the negative control value, the sample was classed as non-irritant.

Applicant's summary and conclusion

Interpretation of results:
other: skin irritant Cat 2
Remarks:
according to EU CLP (EC 1272/2008 and its amendments)
Conclusions:
Two skin irritation test showed tissue viability between 45 and 55%. To be conservative the substance is considered an irritant to the skin Cat 2.
Executive summary:

An in vitro skin irritation study was performed in accordance with OECD 439. As the tissue viability presented borderline result in the range 45 -55%, with a mean of 48% tissue viability. In a second test the mean tissue viability was 55%. A conservative approach has been taken and result in the substance being a skin irritant.