2-[4-(dimethylamino)phenyl]-3,6-dimethylbenzothiazolium chloride

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

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)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-[4-(dimethylamino)phenyl]-3,6-dimethylbenzothiazolium chloride

EC Number:

219-228-9

EC Name:

2-[4-(dimethylamino)phenyl]-3,6-dimethylbenzothiazolium chloride

Cas Number:

2390-54-7

Molecular formula:

C17H19N2S.Cl

IUPAC Name:

2-[4-(dimethylamino)phenyl]-3,6-dimethylbenzothiazolium chloride

Test material form:

solid: particulate/powder

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

This test uses the EPISKIN-SM™ reconstructed human epidermis model (SkinEthic) which consists of normal human epidermal keratinocytes (NHEK) and therefore represents in vitro the target organ of the species of interest and closely mimics the biochemical and physiological properties of the upper parts of the human skin, i.e. the epidermis.

Vehicle:

water

Remarks:

Distilled water (aqua dest.) was applied to the epidermal surface in order to improve further contact between the powder and the epidermis. The water was gently spread on the surface.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

1. Negative control 10 µL DPBS
2. Positive control 10 µL 5% SDS solution
3. Test Item 10 ± 2 mg + 5 µL aqua dest.

Duration of treatment / exposure:

15 min exposure

Duration of post-treatment incubation (if applicable):

42 h post-incubation

Number of replicates:

The test was performed on a total of 3 tissues per dose group

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean value

Value:

ca. 88.1

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions the test item showed no irritant effects. The relative mean tissue viability after 15 min of exposure and 42 h post-incubation was > 50%. The test item is therefore classified as “non-irritant” in accordance with UN GHS “No Category”.

Executive summary:

In the present study theskin irritant potential of Basic Yellow 1 was analysed. The EPISKIN-Standard Model™ (EPISKIN-SM^TM), a reconstituted three-dimensional humanepidermismodel, was used as a replacement for the Draize Skin Irritation Test (OECD TG 404[8]) to distinguish between UN GHS “Category 2” skin irritating test substances and not categorized test substances (“No Category”) which may be considered as non-irritant. Hereby, the test item was applied topically. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT after a 15 min exposure and 42 h post-incubation period and compared to those of the concurrent negative controls.

The test item showed no non-specific MTT-reducing potential. The mixture of the test item with aqua dest. and isopropanol showed colouring potential and absorbed light in the relevant wavelength range, therefore additional viable tissue controls were necessary. Since NSC_livingwas below the 5% threshold value (2.7%), no correction of results was necessary.

The test item showed no irritant effects. The mean relative tissue viability (% negative control) was> 50% (88.1%) after 15 min treatment and 42 h post-incubation.

1.1.       Conclusion

In this study under the given conditions the test item showed no irritant effects. The relative mean tissue viability after 15 min of exposure and 42 h post-incubation was> 50%. The test item is therefore classified as “non-irritant” in accordance with UN GHS “No Category”.