Sodium diisopropylnaphthalenesulphonate

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Version / remarks:

Adopted 29 July 2016

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EC Guideline No. 440/2008. Part B: Methods for the Determination of Toxicity and other health effects, Guideline B.40 BIS: "In Vitro Skin Corrosion: Human Skin Model Test".

Version / remarks:

Official Journal of the European Union No. L142, 31 May 2008

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium diisopropylnaphthalenesulphonate

EC Number:

215-343-3

EC Name:

Sodium diisopropylnaphthalenesulphonate

Cas Number:

1322-93-6

Molecular formula:

C16H20O3S.Na

IUPAC Name:

sodium diisopropylnaphthalene-sulfonate

Test material form:

solid: particulate/powder

Details on test material:

white to off-white lumps

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

Justification for test system used:

Recommended test system in international guidelines (OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used:EpiDerm Skin Model (EPI-200)
- Tissue batch number(s):29600 kit J&K
- Shipping date: 7 November 2018
- Date of initiation of testing: One day after receipt

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: All incubations, with the exception of the test item incubation of 3 minutes at room temperature, were carried out at 37.0 ± 1.0°C (actual range 36.2 -36.7°C).


REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 2
- Observable damage in the tissue due to washing: /
- Modifications to validated SOP: /

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT concentrate (5 mg/ml) diluted (1:5) with MTT diluent (supplemented DMEM). Both supplied by MatTek Corporation.
- Incubation time: 3 hours
- Spectrophotometer: The amount of extracted formazan was determined spectrophotometrically at 570 nm in triplicate with the TECAN Infinite® M200 Pro Plate Reader.
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 2

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
No interference with MTT

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

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the relative mean tissue viability obtained after 3-minute treatment compared to the negative control tissues is decreased below 50%. In addition, a test item considered non-corrosive (viability  50%) after the 3-minute treatment is considered corrosive if the relative tissue viability after 1-hour treatment with the test item is decreased below 15%.
- The test substance is considered to be non-corrosive to skin if the relative mean tissue viability obtained after the 3-minute treatment compared to the negative control tissues is not decreased below 50%. In addition, the relative tissue viability after the 1-hour treatment is not decreased below 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
The skin was moistened with 25 μl Milli-Q water (Millipore Corp., Bedford, Mass., USA) to ensure close contact of the test item to the tissue and 27.2 to 31.0 mg of the solid test item was added into the 6-well plates on top of the skin tissues.

NEGATIVE CONTROL / POSITIVE CONTROL
2 tissues were treated with 50 μl Milli-Q water (negative control) and 2 tissues were treated with 50 μl 8N KOH (positive control)

Duration of treatment / exposure:

The test was performed on a total of 4 tissues per test item together with a negative control and positive control. Two tissues were used for a 3-minute exposure to the test item and two for a 1-hour exposure.

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 hour exposure

Value:

5.2

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minutes exposure

Value:

51

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

CH04207 was checked for color interference in aqueous conditions and possible direct MTT reduction by adding the test item to MTT medium. Because the solutions did not turn blue / purple nor a blue / purple precipitate was observed after 1 hour of incubation, it was concluded that the test item did not interfere with the MTT endpoint.

The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the acceptance limits of OECD 431 (lower acceptance limit ≥0.8 and upper acceptance limit <=2.8) and the laboratory historical control data range. The mean relative tissue viability following the 1-hour exposure for the positive control was 6.3%, thus below 15%.
In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was <=15%, indicating that the test system functioned properly.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Conclusions:

In conclusion, CH04207 is corrosive in the in vitro skin corrosion test under the experimental conditions described in this report and should be classified category 1..

Executive summary:

The objective of this study was to evaluate CH04207 for its ability to induce skin corrosion on a human three dimensional epidermal model (EpiDerm (EPI-200)). The possible corrosive potential of CH04207 was tested through topical application for 3 minutes and 1 hour.

The study procedures described in this report were based on the most recent OECD 431 (2016) and EC 440 (2008) guidelines.

Batch CH04207/AM-CON2 of CH04207 consisted if white to off-white lumps with a purity of >97%. Skin tissue was moistened with 25 µL of Milli-Q water and at least 25 mg of CH04207 was applied directly on top of the skin tissue.

The positive control had a mean relative tissue viability of 6.3% after the 1-hour exposure. The absolute mean OD₅₇₀(optical density at 570 nm) of the negative control tissues waswithin the acceptance limits of OECD 431 (lower acceptance limit ≥0.8 and upper acceptance limit <=2.8) and the laboratory historical control data range. In the range of 20 - 100% viability, the Coefficient of Variation between tissue replicates was <=15%, indicating that the test system functioned properly.

Skin corrosion is expressed as the remaining cell viability after exposure to the test item. The relative mean tissue viability obtained after 3-minute and 1-hour treatments with CH04207 compared to the negative control tissues was 51% and 5.2%, respectively. Because the mean relative tissue viability for CH04207 was below 15% after the 1-hour treatment the substance is considered to be corrosive. 

In conclusion, CH04207 is corrosive in the in vitro skin corrosion test under the experimental conditions described in this report and should be classified category 1.