N,N'-[dithiobis[2-(2-hydroxyethyl)-1-methylvinylene]]bis[N-[(4-amino-2-methyl-5-pyrimidinyl)methyl]formamide

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

12 July 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

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-[dithiobis[2-(2-hydroxyethyl)-1-methylvinylene]]bis[N-[(4-amino-2-methyl-5-pyrimidinyl)methyl]formamide

EC Number:

200-644-4

EC Name:

N,N'-[dithiobis[2-(2-hydroxyethyl)-1-methylvinylene]]bis[N-[(4-amino-2-methyl-5-pyrimidinyl)methyl]formamide

Cas Number:

67-16-3

Molecular formula:

C24H34N8O4S2

IUPAC Name:

N,N'-[dithiobis[2-(2-hydroxyethyl)-1-methylvinylene]]bis[N-[(4-amino-2-methyl-5-pyrimidinyl)methyl]formamide

Test material form:

solid: particulate/powder

Remarks:

Pale yellow powder

Details on test material:

Batch : 18117240
Dose calculation will not be adjusted to purity

In vitro test system

Test system:

human skin model

Remarks:

EpiDerm™ Kit Lot No.: 25806

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

Details on test system:

Epi-200 kits and MTT-100 assays were purchased from MatTek Corporation.

EpiDerm™ Kit :
Lot No.: 25806. The EpiDerm™ tissue consisted of normal, human-derived epidermal keratinocytes which have been cultured to form a multilayered, highly differentiated model of the human epidermis. It consisted of organised basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo. The EpiDerm™ tissues (surface 0.63 cm²) are cultured on specially prepared cell culture inserts (MILLICELL®, 10 mm Ø). EpiDerm™ tissues were shipped at 4 °C on medium-supplemented agarose gels in a 24-well plate and reached Envigo CRS GmbH on 19 April 2017. On day of receipt the pre-incubation phase of the EpiDerm™ tissues started.

MTT-Solution :
The MTT-solution was prepared freshly on day of use (resulting: 1 mg/mL). For use in the pre-test (step 3): MTT from Sigma, Germany, DMEM from Gibco, Germany. For use in the main experiment: MTT concentrate from MatTek, MTT diluent from MatTek.

Amount/concentration applied:

25 ± 2 mg of the test item were added to 1 ml of a MTT/DMEM solution (1 mg/mL).

Duration of treatment / exposure:

• Test Item: 3 ± 0.5 minutes, 60 ± 5 minutes
• Negative Control: 3 ± 0.5 minutes, 60 ± 5 minutes
• Positive Control: 3 ± 0.5 minutes, 60 ± 5 minutes

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

after 3 minutes exposure

Value:

105.4

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other:

Remarks:

Non corrosive

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

After 1 hour exposure

Value:

106.5

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other:

Remarks:

non corrosive

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Remarks:

The test item is non corrosive to skin according to EU CLP and UN GHS.

Conclusions:

After exposure to the test item 5007 TDS HYDRATE SEC the relative absorbance value did not decrease (105.4%) after 3 minutes exposure. After 1 hour exposure the relative absorbance value was not reduced (106.5%). Both values did not affect the threshold for corrosivity which is defined to be 50% after the 3 minutes exposure and 15% after the 1 hour exposure. Therefore, the test item is not considered to be corrosive.
In conclusion, it can be stated that in this study and under the reported experimental conditions, the substance tested is non corrosive to skin according to EU CLP and UN GHS.

Executive summary:

This in vitro study was performed to assess the corrosive potential of the substance named 5007 TDS HYDRATE SEC by means of the Human Skin Model Test with EpiDerm™ tissues models.

The test item did not reduce MTT (test for direct MTT reduction), and it did not change colour when mixed with deionised water (test for colour interference). Consequently, additional tests with freeze-killed or viable tissues to determine correction factors for calculating the true viability in the main experiment were not necessary.

Independent duplicate tissues of EpiDerm™ were exposed to either the test item, the negative control (deionised water) or the positive control (8.0 N KOH) for 3 minutes and 1 hour, respectively.

After exposure to the negative control the absorbance values met the required acceptability criterion of a mean OD570 ≥ 0.8 and ≤ 2.8 for both treatment intervals thereby confirming the acceptable quality of the tissues.

Exposure to the positive control induced a decrease in the relative absorbance as compared to the negative control, both for the 3 minutes exposure period and for the 1 hour exposure period. The 1 hour exposure caused a decrease of the cell viability < 15% of the negative control. The CV in the range 20 – 100% viability between the tissue replicates is ≤ 30%, thus the validity of the test system and the specific batch of the tissue models is confirmed.

After exposure of the tissues to the test item the relative absorbance value did not decrease (105.4%) after 3 minutes exposure. After 1 hour exposure the relative absorbance value was also not reduced (106.5%). Both values did not affect the threshold for corrosivity which is defined to be 50% after the 3 minutes exposure and 15% after the 1 hour exposure. Therefore, the test item is not considered to be corrosive.

In conclusion, it can be stated that in this study and under the reported experimental conditions, the test item 5007 TDS HYDRATE SEC is non corrosive to skin according to EU CLP and UN GHS.