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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:
09 May 2012 to 11 May 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
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. The study report was conclusive, done to a valid guideline and the study was conducted under GLP conditions.

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Substance type: white to pale yellow powder, a slightly characteristic odour.
- Storage condition of test material: room temperature

Test system

Vehicle:
unchanged (no vehicle)
Amount / concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 20 mg.
Duration of treatment / exposure:
15 minutes

Results and discussion

In vivo

Other effects:
CELL VIABILITY
- The viability results of the test material treated disks was 88 % of the negative control, since this is > 50 % of the negative control the test material is considered to be a non-irritant.

VALIDITY OF THE TEST
The mean OD value of the three negative control tissues was 0.756. The positive control result showed a mean of 6.9 % viability. Each standard deviation value (SD) of the % viability was below 18. All validity criteria were within acceptable limits and therefore the study can be considered as valid.

INDICATOR FOR POTENTIAL FALSE VIABILITY
> Possible direct MTT reduction with the test material: No colour change was observed after three hours of incubation of the test item in MTT solution. The test material did not interact with the MTT, therefore additional controls and data calculations were not necessary. A false estimation of viability due the MTT interaction can be precluded.
> Colouring potential of the test material: As the test material is coloured, one additional chemical-treated tissue was used for the non specific OD evaluation. Optical Density (measured at 540 nm) of this tissue was determined as 0.034, Non Specific Colour % was calculated as 4.5 %, below the threshold of 50 %. Therefore additional data calculation was not necessary.

Any other information on results incl. tables

Table 1: Optical Density (OD) and the Calculated % Viability

 Substance

Optical Density (OD)

Viability (%)

Negative Control

1

0.820

108

2

0.659

87

3

0.788

104

Mean

0.756

100

(SD)

 

11.15

Positive Control

1

0.040

5.3

2

0.079

10

3

0.041

5.4

Mean

0.053

6.9

(SD)

 

2.69

Test Material

1

0.721

95

2

0.536

71

3

0.746

99

Mean

0.668

88

(SD)

 

15.14

Applicant's summary and conclusion

Interpretation of results:
not irritating
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Under the conditions of the test, the results indicate that the test material is not a skin irritant.
Executive summary:

The potential for the test material to cause skin irritation was predicted in vitro using the EPISKIN Model in a study conducted under GLP conditions and in line with OECD 439 and EU Method B.46. The test material was applied topically to the surface of the skin for 15 minutes, which was terminated by rinsing with PBS 1 x solution (0.9 %). Epidermis units were then incubated at 37 °C for 42 hours in an incubator with 5 % CO2. The viability of each disk was assessed by incubating the tissues for 3 hours with MTT solution at 37 °C in 5 % CO2 protected from light. The formazan extract in acidified isopropanol was then spectrophotometrically evaluated for optical density (OD) and quantified. Positive and negative controls were run concurrently and tissue viability was expressed as a % relative to the negative control.

Under the conditions of the study, exposure to the test material resulted in a mean relative cell viability of 88 %. Since the cell viability was determined to be > 50 % of the negative control the test material was considered to be non-irritating.