2-[[4-(dimethylamino)phenyl]azo]-1,3-dimethyl-1H-imidazolium 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:

Reported on the 15Apr2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

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)

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

not specified

GLP compliance:

not specified

Remarks:

Only summary report is available - GLP compliace and QA not specified.

Test material

Test material information

Constituent 1

Reference substance name:

2-[[4-(dimethylamino)phenyl]azo]-1,3-dimethyl-1H-imidazolium chloride

EC Number:

278-601-4

EC Name:

2-[[4-(dimethylamino)phenyl]azo]-1,3-dimethyl-1H-imidazolium chloride

Cas Number:

77061-58-6

Molecular formula:

C13H18N5.Cl

IUPAC Name:

2-[[4-(dimethylamino)phenyl]azo]-1,3-dimethyl-1H-imidazolium chloride

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Name of test substance: Vibracolor ruby red
Test substance No.: 10/0383-3
Batch identification: 0009051093
CAS No.: 77061-58-6

In vitro test system

Test system:

human skin model

Remarks:

Human reconstituted epidermis model EpiDerm™

Source species:

human

Cell type:

other: cell type not specified "Human reconstituted epidermis model EpiDerm™"

Cell source:

other: cell source not specified "Human reconstituted epidermis model EpiDerm™"

Source strain:

other: source strain not specified "Human reconstituted epidermis model EpiDerm™"

Vehicle:

unchanged (no vehicle)

Control samples:

yes, concurrent negative control

yes, concurrent positive control

yes, concurrent MTT non-specific colour control

Amount/concentration applied:

Two EpiDerm ™ tissue samples were incubated with 25 μL bulk volume (about 10 mg) of the
undiluted test substance for 3 minutes and 1 hour (corrosion test). Three EpiDerm TM tissue
samples were incubated with 25 μL bulk volume (about 10 mg) of the undiluted test
substance for 1 hour with 42 hours postincubation (irritation test).

Duration of treatment / exposure:

3 minutes and 1 hour (corrosion test).
1 hour with 42 hours postincubation (irritation test).

Duration of post-treatment incubation (if applicable):

42 hours postincubation (irritation test).

Number of replicates:

Duplicate

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

OECD 439In vitro skin irritation test; Final mean variability of tissues after Color Control correction

Value:

45.5

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Remarks:

On the basis that this test substance is non-corrosive in TG 431, the result of <50% viability in this test would indicate a skin irritation IN GHS Category 2 classification.

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

OECD 431 In vitro corrosion test; final mean viability of tissues after colour control correction correction

Value:

93.9

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: Not corrosive according to the criteria in this test

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Remarks:

According to TG 439 where a test chemical is found to be non-corrosive in test TG 431 and where the tissue viability after exposure and post-treatment is <50%, the test chemical is considered to be irritant in accordance with UN GHS Category 2.

Conclusions:

In this OECD TG 431 and TG 439 study the tst substance was found to be non-corrosive according to TG 431. According to TG 439, with a tissue viability percentage after colour control correction of 45.5%, the test chemical is irritating.
According to TG 439 where a test chemical is found to be non-corrosive in test TG 431 and where the tissue viability after exposure and post-treatment is <50%, the test chemical is considered to be irritant in accordance with UN GHS Category 2.

Executive summary:

The objective was to assess the potential for corrosive activity and skin irritation of Vibracolor ruby red. Using the currently available methods a single in vitro assay may not always be sufficient to cover the full range of skin irritating/corrosion potential. Therefore, two in vitro assays were part of this in vitro skin irritation and corrosion test strategy: The Skin Corrosion Test (SCT) (OECD TG 431) and Skin Irritation Test (SIT) (OECD TG 439).

The tests were performed according to the test guidelines and as the test chemical is coloured and to avoid colour interferences with the test methods colour controls and freeze-killed control tissues were included in the study as described in the study guidelines.

In the skin corrosion test (TG 431), after 3 minutes the results of the color control (CC) tissues indicate interference due to the color of the test substance (mean value 3.7% of NC). The results of the KC tissues did not indicate an increased MTT reduction. Thus for the test substance the final mean viability is given after CC correction and was 93.9%; a non-corrosive prediction. After a 1 hour exposure period, the results of the color control (CC) tissues indicate interference due to the color of the test substance (mean value 17.2% ofNC).The results of the KG tissues indicate an increased MTT reduction (mean viability 0.2% of NC). Thus for the test substance the final mean viability is given after CC and KC correction and is 75.1%; a non-corrosive prediction.

In the skin irrtation test (TG 439), although red discoloration of the tissues was observed, no extraction of the test substance into the isopropanol was obtained.The results of the KC tissues did not indicate an increased MTT reduction. Thus for the test substance the final mean viability is given without CC and KC correction and is 45.5%. As this is less than the criteria of less than or equal to 50% the results are indicative of skin irritation.

According to TG 439 where a test chemical is found to be non-corrosive in test TG 431 and where the tissue viability after exposure and post-treatment is <50%, the test chemical is considered to be irritant in accordance with UN GHS Category 2.