Phenol, 4-(phenylamino)-, sulfurized, leuco deriv.

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

18-Jun-2012 to 10-Sep-2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: EU method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: OECD Guideline no. 439: In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

phenol, 4-(phenylamino)-, sulfurised, leuco deriv.

Molecular formula:

not applicable

IUPAC Name:

phenol, 4-(phenylamino)-, sulfurised, leuco deriv.

Test system

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): The skin was moistened with 5 µl Milli-Q water to ensure close contact of the test substance to the tissue and the pasty test substance was added on top of the skin tissues using a cotton swab. Consequently, the exact amount of test substance applied was unknown.

NEGATIVE CONTOL:
- Amount(s) applied (volume or weight with unit): 25 µl Phosphate buffered saline

POSITIVE CONTROL
- Amount(s) applied (volume or weight with unit): 25 µl
- Concentration (if solution): 5% (aq) Sodium dodecyl sulphate

Duration of treatment / exposure:

Exposure:15 minutes
Post incubation period: 42 hours

Details on study design:

TEST SITE
- Area of exposure: human epidermis model
- % coverage: 0.38 cm2

REMOVAL OF TEST SUBSTANCE
- Washing (if done): phosphate buffered saline
- Time after start of exposure: 15 minutes

POST INCUBATION PERIOD
- 42 hours

SCORING SYSTEM:
- After a 42 hour incubation period, determination of the cytotoxic (irritancy) effect was performed. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT at the end of the treatment. Cell viability was calculated for each tissue as a percentage of the mean of the negative control tissues.

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

other: percentage viability

Remarks:

percentage of control / time point: 15 minutes

Value:

98

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction: C.I. Leuco Sulphur Brown 96 was checked for possible direct MTT reduction by adding the test substance to MTT medium. Because no colour change was observed it was concluded that C.I. Leuco Sulphur Brown 96 did not interact with MTT.

Any other information on results incl. tables

The positive control had a mean cell viability after 15 minutes exposure of 46% and did not meet the acceptability criteria. Approximately 1 hour after the performance of this test another in vitroskin irritation test was performed using the same batch of skin and the same batch of 5% (aq) SDS. The positive control had a mean cell viability of 5% and met the acceptability criteria. The absolute mean OD₅₇₀of the negative control tissues (in both in vitro skin irritation tests) were within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was less than 11%, indicating that the test system functioned properly. It can be concluded that the deviation in the mean cell viability of the positive control in the first in vitro skin irritation test was caused by a technical error.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Conclusions:

Based on an in vitro skin irritation test, conducted according to OECD 439 guideline, the test item is considered not to be irritant.

Executive summary:

An in vitro test in reconstructed human skin (OECD 439) was performed to assess the irritation/corrosion potential of the test item. Twenty-five µL of the test substance were applied to the skin for 15 minutes. After test substance removal and a post incubation period of 42 hours the cytotoxicity was determined by means of Formazan reduction to MTT.

The relative mean tissue viability obtained after 15 minutes treatment with C.I. Leuco Sulphur Brown 96 compared to the negative control tissues was 98%. Since the mean relative tissue viability for C.I. Leuco Sulphur Brown 96 was above 50% after 15 minutes treatment C.I. Leuco Sulphur Brown 96 is considered to be non-irritant.