3-(benzothiazol-2-yl)-7-(diethylamino)-2-oxo-2H-1-benzopyran-4-carbonitrile

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

1111

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3-(benzothiazol-2-yl)-7-(diethylamino)-2-oxo-2H-1-benzopyran-4-carbonitrile

EC Number:

274-668-9

EC Name:

3-(benzothiazol-2-yl)-7-(diethylamino)-2-oxo-2H-1-benzopyran-4-carbonitrile

Cas Number:

70546-25-7

Molecular formula:

C21H17N3O2S

IUPAC Name:

3-(1,3-benzothiazol-2-yl)-7-(diethylamino)-2-oxo-2H-chromene-4-carbonitrile

Test material form:

solid

Specific details on test material used for the study:

Batch number: CHA91249
Purity: 97.6 %

In vitro test system

Test system:

artificial membrane barrier model

Source species:

human

Cell type:

other: reconstructed human epidermis

Cell source:

other: reconstructed human epidermis

Source strain:

other: reconstructed human epidermis

Justification for test system used:

Human full thickness skin models and reconstituted epidermal equivalents are in vitro engineered tissue cultures that provide a three dimensional architecture which is biochemically, morphologically and functionally comparable to human epidermal tissue/skin in vivo. In contrast, organotypic skin explant systems are based on ex vivo skin removed from human or mouse and cultured in toto, afterwards. According to the literature all the models are useful in screening for topically applied irritant, corrosive or photocytotoxic substances.

Vehicle:

unchanged (no vehicle)

Details on test system:

The model used for this study has a functional stratum corneum with an underlying layer of living cells as recommended by the test guidelines. The barrier function of the stratum corneum is adequate, as has been shown by the supplier.

The viability of the living cells in the model must be sufficiently high to discriminate well between the positive and negative control substances. Cell viability is measured by the amount of MTT reduction, i.e. an OD value, following exposure to the negative control substance or the test item.

Control samples:

yes, concurrent vehicle

yes, concurrent positive control

yes, concurrent MTT non-specific colour control

Amount/concentration applied:

Three replicates of the epiCS inserts were exposed to the test item (30 mg), negative or positive control (each 30 µl). For the solid test item 30 µl of 0.9% NaCl were used to moisten and ensure good contact with the epidermis surface. A piece of nylon mesh was used as a spreading aid.

Duration of treatment / exposure:

The incubation of the treated epiCS inserts was carried out at RT for 20 min.

Duration of post-treatment incubation (if applicable):

After a post treatment incubation period of 42 h of the rinsed tissue in the incubator a MTT assay was performed

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean of 3 replicates

Value:

98.81

Vehicle controls validity:

valid

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

Executive summary:

A study was performed for the assessment of the skin irritancy of the test item Macrolex Fluoreszenzrot G with reconstructed human epidermis (RhE). The experiment was carried out in vitro using the commercially available test method epiCS®.

The study was conducted in accordance with OECD TG 439 and EU Test Method B.46.

The test item was applied undiluted topically to the RhE tissue construct in triplicates and incubated for 20 minutes, followed by a 42 hours post-treatment incubation period.

Cell viability was measured in a photometer by the amount of MTT (methylthiazole tetrazolium) reduction. The optical density value obtained for the test item was used to calculate the percentage of viability relative to the negative control, which is set at 100%.

The results of the concurrent negative control (NC, 0.9 % NaCl) and positive control (PC, 5 % SDS) demonstrated the viability (NC) and sensitivity (PC) of the test model.

The following value of cell viability was recorded for the test item: 99 % (rounded).

In conclusion the results of the assay used show no skin irritant properties of the test item Bayscript Magenta BB and thus, the test item requires no classification according to UN GHS.