2,3-Quinoxalinedione, 1,4-dihydro-6-methoxy-7-nitro-

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to: OECD Guideline for the Testing of Chemicals 439: In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method (Original Guideline adopted July 22, 2010) with GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline for the Testing of Chemicals 439: In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method (Original Guideline adopted July 22, 2010)

Deviations:

not specified

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1,4-Dihydro-6-methoxy-7-nitroquinoxaline-2,3-dione

EC Number:

614-960-9

Cas Number:

69399-57-1

Molecular formula:

C9H7N3O5

IUPAC Name:

1,4-Dihydro-6-methoxy-7-nitroquinoxaline-2,3-dione

Details on test material:

Identity: Nitro-C-Dion trocken (NMQD)
CAS No.: 69399-57-1
Purity: 91.0% (w/w), dose calculation not adjusted to purity
Stability in Solvent: Not relevant
Storage: At room temperature

Test system

Amount / concentration applied:

Each approximately 10 mg of the neat test item were applied to three EPISKIN (Skinethic) tissues. Additionally, the tissues were wetted with 15 µL of deionised water.

Duration of treatment / exposure:

The skin equivalents were exposed to the test item for 15 minutes. After completion of the treatment the test item was rinsed off and the skin equivalents were incubated for further 42 hours.

Details on study design:

Each approximately 10 mg of the neat test item and 10 µL of the negative control (deionised water) ot the positive control (5% SLS) were applied to three EPISKIN (Skinethic) tissues. Additionally, the test item treated tissues were wetted with 15 µL of deionised water. The test item as well as the controls were rinsed off after 15 minutes treatment. After further 42 hours incubation the tissues were treated with the MTT solution for 3 hours following approximately 69 hours extraction of the colorant from the cells. The amount of extratced colorant was determined photometrically at a wavelength of 570 nm.

Results and discussion

In vivo

Irritant / corrosive response data:

After treatment with the test item Nitro-C-Dion trocken (NMQD) the relative absorbance value did not decrease (107.6%; threshold for irritancy: ≤ 50%). Therefore, the test item is not considered to possess an irritant potential.

Any other information on results incl. tables

Results after treatment with Nitro-C-Dion trocken (NMQD) and controls

 

Dose group	Treatment Interval	Absorbance 570 nm Tissue 1*	Absorbance 570 nm Tissue 2*	Absorbance 570 nm Tissue 3*	Mean Absorbance of 3 Tissues	Relative Absorbance [%] Tissue 1, 2 + 3**	Standard Deviation [%]	Rel. Absorbance [% of Negative Control]***
Negative Control	15 min	0.907	0.844	0.889	0.880	103.0 95.9 101.1	3.7	100.0
Positive Control	15 min	0.278	0.233	0.156	0.222	31.6 26.5 17.7	7.0	25.3
Test Item	15 min	0.928	0.921	0.992	0.947	105.5 104.6 112.7	4.4	107.6

*       Mean of two replicate wells after blank correction

**      relative absorbance per tissue [rounded values]:
***    relative absorbance per treatment group [rounded values]:

Optical evaluation of the MTT-reducing capacity of the test item after 1 hour incubation with MTT-reagent did not show blue colour.

The relative absorbance value of the test item, corresponding to the cell viability, did not decrease (107.6%; threshold for irritancy:≤50%), consequently the test item was non irritant to skin.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: OECD GHS

Conclusions:

In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item Nitro-C-Dion trocken (NMQD) is non irritant to skin.

Executive summary:

This in vitro study was performed to assess the irritation potential of Nitro-C-Dion trocken (NMQD) by means of the Human Skin Model Test.

Three tissues of the human skin model EpiSkin™ were treated with the test item, the negative or the positive control for 15 minutes.

Approximately 10 mg of the test item were applied to each tissue, wetted with 15 µL of deionised water, and spread to match the tissue size.

The test item and the positive and negative controls were washed off the skin tissues after 15 minutes treatment. After further incubation for about 42 hours the tissues were treated with the MTT solution for 3 hours following 69 hours extraction of the colorant from the cells. The amount of extracted colorant was determined photometrically at 570 nm.

10 µL of either the negative control (deionised water) or the positive control (5% Sodium lauryl sulfate) were applied to each tissue.

After treatment with the negative control the absorbance values were well within the required acceptability criterion of mean OD equal or greater than 0.6 till ≤1.5 for the15 minutes treatment interval thus showing the quality of the tissues.

Treatment with the positive control induced a decrease in the relative absorbance as compared to the negative control to 25.3% thus ensuring the validity of the test system.

The standard deviations between the % variabilities of the test item, the positive and negative controls were below 8% (threshold of the "OECD TG 439 Guideline for the Testing of Chemicals 439: In vitro Skin Irritation: Reconstructed Human Epidermis Test Method”: 18%),thus ensuring the validity of the study.

After treatment with the test item Nitro-C-Dion trocken (NMQD) the relative absorbance value did not decrease (107.6%; threshold for irritancy:≤50%). Therefore, the test item is not considered to possess an irritant potential.