3-methyltetrahydrothiophene 1,1-dioxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 Sep 2017 - 16 Oct 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

28 July 2015

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

20 July 2012

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

3-methyltetrahydrothiophene 1,1-dioxide

EC Number:

212-833-9

EC Name:

3-methyltetrahydrothiophene 1,1-dioxide

Cas Number:

872-93-5

Molecular formula:

C5H10O2S

IUPAC Name:

3-methyl-1λ⁶-thiolane-1,1-dione

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: Adult donors 17-EKIN-041

Source strain:

other: 09-KERA-007 09-KERA-010

Justification for test system used:

In the interest of sound science and animal welfare, a sequential testing strategy is recommended to minimize the need of in vivo testing. One of the validated in vitro skin irritation tests is the EPISKIN test, which is recommended in international guidelines (e.g. OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN Small ModelTM (EPISKIN-SMTM, 0.38 cm2)
- Tissue batch number(s): Batch no.: 17-EKIN-041
- Production date: 10 Oct 2017
- Date of initiation of testing: 10 Oct 2017

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: room temperature
- Temperature of post-treatment incubation (if applicable): 37C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: untill all test item was removed
- Observable damage in the tissue due to washing: no

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL in PBS
- Incubation time: 3 h
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader.
- Wavelength: 570nm

NUMBER OF REPLICATE TISSUES: 3

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA
- A test item is considered irritant in the skin irritation test if:
The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is ≤ 50% of the mean viability of the negative controls.
- A test item is considered non-irritant in the in vitro skin irritation test if:
The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is > 50% of the mean viability of the negative controls.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 µL
- Concentration (if solution): Undiluted

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 25µL
- Concentration (if solution): undiluted

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 25µL
- Concentration (if solution): 5%

Duration of treatment / exposure:

15 ± 0.5 minutes

Duration of post-treatment incubation (if applicable):

42 hours at 37°C

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Main

Value:

101

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction: No
- Colour interference with MTT: No

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes
- Acceptance criteria met for variability between replicate measurements: Yes
- Range of historical values if different from the ones specified in the test guideline: refer to table

Any other information on results incl. tables

Historical Control Data for In Vitro Skin Irritation Studies

	Negative control (absorption; OD570)	Positive control (absorption; OD570)
Range	0.676 – 1.336	0.036 – 0.549
Mean	1.01	0.16
SD	0.16	0.10
n	155	154

SD = Standard deviation

n = Number of observations

The above mentioned historical control data range of the controls were obtained by collecting all data over the period of November 2013 to November 2016.

Applicant's summary and conclusion

Interpretation of results:

other: not irritant

Remarks:

in accordance with Annex I of 1272/2008/EC (CLP)

Conclusions:

Based on the results of this study 3-methyl sulfolane does not need to be classified for skin irritation in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).

Executive summary:

3-Methyl Sulfolane was evaluated for its ability to induce skin irritation on a human three dimensional epidermal model (OECD TG 439 (EPISKIN-SMTM)). The test item was applied undiluted (25 µl), directly on top of the skin tissue for 15 ± 0.5 minutes. After a 42 hour post-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.

Skin irritation is expressed as the remaining cell viability after exposure to the test item. The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with the test item compared to the negative control tissues was 101%. Since the mean relative tissue viability for the test item was above 50% after 15 ± 0.5 minutes treatment the test item is considered to be non-irritant.

The positive control had a mean cell viability of 10% after 15 ± 0.5 minutes exposure. The absolute mean OD570(optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was < 5%, indicating that the test system functioned properly.

In conclusion, 3-Methyl Sulfolane is non-irritant in the in vitro skin irritation test under the experimental conditions described in this report andshould not be classified according to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) of the United Nations and according tothe criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).