Niobium sulfur tin zinc oxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions. Lack of data on analytical purity of the test substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method, adopted July 2010)

Deviations:

yes

Remarks:

Lack of data on analytical purity of the test substance.

GLP compliance:

yes (incl. QA statement)

Remarks:

Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit, Landesinstitut für Arbeitsschutz und Produktsicherheit, München

Test material

Test material information

Constituent 1

Reference substance name:

niobium oxygen sulfur zinc λ²-stannane

EC Number:

800-035-9

Cas Number:

1374645-21-2

Molecular formula:

Sn1.8Zn0.2Nb2O6.8S0.2 (Sn(2-x)Zn(x)Nb2O(7-y)S(y) with x/2 ≤ y, 0.02 ≤ x ≤ 0.22, 0.01 ≤ y ≤ 0.22)

IUPAC Name:

niobium oxygen sulfur zinc λ²-stannane

Details on test material:

- Name of test material (as cited in study report): Niobium Sulfur Tin Zinc Oxide Lot No. Ex 1455
- Physical state: solid
- Appearance: yellow powder
- Analytical purity: no data
- Lot No.: L1903
- pH value: 6.1
- Storage condition of test material: at room temperature

Test animals

Species:

human

Strain:

other: EPISKIN-Standard Model™; reconstituted three-dimensional human epidermis

Details on test animals or test system and environmental conditions:

TEST SKIN MODEL
- Source: SkinEthic, Lyon, France

TEST METHOD
The model represents a reconstructed three-dimensional skin model based on normal human-derived epidermal keratinocytes which have been cultured to form a multilayered epidermis including basal, spinous and granular layers, and a multi-layered stratum corneum. Irritant materials are identified by their ability to penetrate the stratum corneum and to damage the underlaying cell layers which is determined through a decrease in cell viability as determined by MTT reduction assay.

ADAPTATION TO CELL CULTURE CONDITIONS
Upon receipt, tissues were transferred into 12-well plates containing 2 mL prewarmed assay medium per well and preincubated in a humidified incubator for at least 24 h (37 ± 1 °C, 5% CO2) before use.

INCUBATION CONDITIONS (INCUBATOR)
- Temperature (°C): 37 ± 1
- CO2 gas concentration (%): 5
- Humidity: maximum

Test system

Type of coverage:

other: open: in vitro system

Preparation of test site:

other: intact reconstructed human epidermis

Vehicle:

unchanged (no vehicle)

Controls:

other: Concurrent control tissues treated with PBS served as negative controls, positive controls were exposed to 5% SDS in distilled water.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 mg (26.3 mg/cm2) moistened with 10 µL distilled water

CONTROL SUBSTANCES
- Positive control substance: 5% sodium dodecyl sulfate (SDS) in distilled water
- Negative control substance: Phosphate Buffered Saline (PBS)

Duration of treatment / exposure:

15 ± 0.5 min

Observation period:

Not applicable. Post-treatment period: 42 ± 1 h.

Number of animals:

Not applicable. The test was performed in triplicates for each treatment and control group.

Details on study design:

TEST SITE
- Area of exposure: 0.38 cm2


REMOVAL OF TEST SUBSTANCE
- Washing (if done): The treated skin surfaces were washed with PBS to remove the test substance.
- Time after start of exposure: 15 ± 0.5 min
- Post-treatment period: 42 ± 1h

CELL VIABILITY MEASUREMENTS:
For determining alterations in cell viability, MTT reduction assays were performed after the post-treatment period. Therefore, tissues were incubated in 2 mL prewarmed MTT solution for 3 h ± 5 min at 37 ± 1 °C and 5% CO2. After this, the tissues were dried on blotting paper. Extraction of the formazan product was carried out in 0.5 mL acidic isopropanol over the weekend at 2 - 8 °C. The optical density (OD) was measured at 550 nm in a plate spectrophotometer.

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

other: other: cell viability

Value:

100

Remarks on result:

other:

Remarks:

Basis: other: mean value of the negative control (PBS). Time point: 15 min. Reversibility: other: not applicable. (migrated information)

Results 2

Irritation / corrosion parameter:

other: other: cell viability (% of negative control)

Value:

2.9

Remarks on result:

other:

Remarks:

Basis: other: mean value of the positive control (5% SDS in distilled water). Time point: 15 min. Reversibility: other: not applicable. (migrated information)

Results 3

Irritation / corrosion parameter:

other: other: cell viability (% of negative control)

Value:

92.6

Remarks on result:

other:

Remarks:

Basis: other: mean value of the test substance in distilled water. Time point: 15 min. Reversibility: other: not applicable. (migrated information)

Any other information on results incl. tables

Table 1: MTT assay after 15 min exposure

	Negative Control			Positive Control			Test substance
Tissue sample	1	2	3	1	2	3	1	2	3
OD550(absolute)	1.269 1.292	1.036 1.050	1.107 1.129	0.077 0.077	0.072 0.077	0.075 0.077	1.117 1.103	1.023 1.047	1.065 1.038
corrected OD550-blank	1.225 1.248	0.992 1.006	1.063 1.085	0.033 0.033	0.028 0.033	0.031 0.033	1.073 1.059	0.979 1.003	1.021 0.994
OD550(mean of duplicates)	1.237	0.999	1.074	0.033	0.031	0.032	1.066	0.991	1.008
OD550(mean of 3 replicates) ± SD	1.103 ± 0.11			0.032 ± 0.00			1.022 ± 0.04
Relative tissue viabilities (%)	112.1	90.6	97.4	3.0	2.8	2.9	96.6	89.8	91.3
Mean tissue viability (%) ± SD	100.0 ± 11.0			2.9 ± 0.1			92.6 ± 3.6

Blank = 0.044

SD: standard deviation

The MTT assay conducted with the test substance met the test acceptance criteria. Since the tissue viability after exposure and post-treatment incubation period is above 50%, the test substance is considered as non-irritant.

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified
DSD: not classified