Niobium sulfur tin zinc oxide

Eye irritation

Administrative data

Endpoint:

eye 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 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosive and Severe Irritants, adopted: 7 Sept 2009

Deviations:

yes

Remarks:

Lack of data on analytical purity of the test substance.

GLP compliance:

yes (incl. QA statement)

Remarks:

Bayrisches 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
- Storage condition of test material: at room temperature

Test animals / tissue source

Species:

other: cattle

Details on test animals or tissues and environmental conditions:

TEST METHOD
The bovine corneal opacity and permeability (BCOP) test is an in-vitro test method used to classify substances as “ocular corrosives and severe irritants”. The potential of a test substance to cause ocular corrosivity or severe irritancy is measured by its ability to induce opacity and increased permeability in an isolated bovine cornea. The opacity and permeability assessments of the cornea are combined to derive an in-vitro irritancy score (IVIS), which is used to classify the irritancy level of the test substance.

IDENTIFICATION OF THE SOURCE OF THE EYES, STORAGE AND TRANSPORT CONDITIONS
- Source: Attenberger Fleisch GmbH & Co. KG., Munich, Germany
- Date of eye collection: 10 Jan 2012
- Transport medium and temperature conditions: Hanks´ Balanced Salt Solution (HBSS) with penicillin/streptomycin, on ice

PREPARATION OF THE EYES (BEFORE EXPOSURE)
- Eyes free of defects (scratches, neovascularisation): yes
- Dissection of the eyes and treatment: Corneas were dissected with a 2 to 3 mm rim of sclera. Isolated corneas were mounted in cornea holders.
- Type of cornea holder used: MC2, Clermont, France
- Description of the cornea holder: The cornea holders consist of an anterior and a posterior compartment, which interface with the epithelial and endothelial sides of the cornea.
- Test medium and temperature conditions used in the cornea holder: RPMI Medium (RPMI) with and without phenol red, supplemented with 1% (v/v) fetal calf serum, RPMI with phenol red additionally supplemented with 2 mM L-glutamine; prior to use: pre-warmed to 32 ± 1 °C
- Quality check of the equilibrated corneas: value for the initial opacity

DETERMINATION OF THE INITIAL OPACITY
- Method: Corneal opacity was determined by the amount of light transmission through the cornea via an opacitometer.
- Specification of the device: The opacitometer was purchased from the company MC2, Clermont, France.

Test system

Vehicle:

other: physiological saline (0.9% w/v NaCl)

Controls:

other: number of eyes for the negative control: 3; number of eyes for the positive control: 3

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 750 µL
- Concentration (if solution): 20%

VEHICLE
- Substance: physiological saline
- Concentration (if solution): 0.9%
- Amount(s) applied (volume or weight with unit): 750 µL
- Lot/batch no. (if required): 110900

POSITIVE CONTROL
- Substance: imidazole
- Concentration (if solution): 20% in physiological saline
- Amount(s) applied (volume or weight with unit): 750 µL
- Lot/batch no. (if required): 109K5306V

Duration of treatment / exposure:

4 h ± 5 min at 32 ± 1 °C

Observation period (in vivo):

not applicable

Number of animals or in vitro replicates:

number of eyes for the test substance: 3

Details on study design:

TEST CONDITIONS
- Short description of the method used: closed-chamber method
Closed-Chamber method: The controls or test substance were applied through dosing holes on the top surface of the anterior chamber to cover the epithelial surface of the cornea. After dosing, the holes are subsequently closed with the chamber plugs. Corneas were exposed for 4 h with the test substance or the controls.

POST-EXPOSURE TREATMENT
- Removal of the test substance: The test substance was removed from the anterior chamber and the epithelium washed at least three times.
- Medium for washing the corneas: minimum essential medium (MEM) with phenol red
- Medium for final rinsing: RPMI without phenol red and supplemented with 1% (v/v) FBS and 2 mM L-glutamine

DETERMINATION OF THE FINAL OPACITY
- Method: Corneal opacity was determined by the amount of light transmission through the cornea via an opacitometer.
- Time of determination: Directly after refilling fresh RPMI without phenol red and supplemented with 1% (v/v) FBS and 2 mM L-glutamine in the anterior chamber, the final opacity was measured.
- Specification of the device: The opacitometer was purchased from the company MC2, Clermont, France.

DETERMINATION OF THE CORNEAL PERMEABILITY:
- Method: Sodium fluorescein solution was added to the anterior chamber of the cornea holder while the posterior chamber was filled with fresh medium. The amount of sodium fluorescein that crosses into the posterior chamber was quantitatively measured via UV/VIS spectrophotometry at 490 nm recorded as optical density (OD490).
- Amount and concentration of the dye: 1 mL sodium fluorescein solution (5 mg/mL)
- Incubation time: 90 min at 32 ± 1 °C

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

other: opacity

Basis:

other: mean out of all 3 eyes

Time point:

other: 4 h

Score:

18

Reversibility:

other: not applicable

Remarks on result:

other: Test substance

Results 2

Irritation parameter:

other: permeability

Basis:

other: mean out of all 3 eyes

Time point:

other: 4 h

Score:

-0.001

Reversibility:

other: not applicable

Remarks on result:

other: Test substance

Results 3

Irritation parameter:

other: IVIS

Basis:

other: mean out of all 3 eyes

Time point:

other: 4 h

Score:

17.99

Reversibility:

other: not applicable

Remarks on result:

other: Test substance

Results 4

Irritation parameter:

other: opacity

Basis:

other: mean out of all 3 eyes

Time point:

other: 4 h

Score:

174.67

Reversibility:

other: not applicable

Remarks on result:

other: Positive control

Results 5

Irritation parameter:

other: permeability

Basis:

other: mean out of all 3 eyes

Time point:

other: 4 h

Score:

1.902

Reversibility:

other: not applicable

Remarks on result:

other: Positive control

Results 6

Irritation parameter:

other: IVIS

Basis:

other: mean out of all 3 eyes

Time point:

other: 4 h

Score:

203.2

Reversibility:

other: not applicable

Remarks on result:

other: Positive control

Any other information on results incl. tables

DATA EVALUATION

- Calculation of opacity values:The opacity value was calculated by subtracting the initial opacity reading from the final opacity reading. These values were corrected by subtracting from each the average change in opacity of the negative control corneas. Finally, the mean opacity value for each treatment group was calculated by averaging the single corrected opacity values of each cornea of the treatment group.

 

- Calculation of OD490 (optical density at 490 nm) values:

The permeability value was calculated according to the following steps:

- corrected OD490 change = OD490 change – mean OD490 change of negative control

- mean OD490 value = mean of all corrected OD490 changes per group

 

- Calculation of the IVIS (in-vitro irritancy score) values:

The In-Vitro Irritancy Score (IVIS) was calculated as follows:

- IVIS per cornea = corrected opacity change + (15 x corrected OD490 change)

- IVIS per treatment group = mean of all IVIS per group

 

- Evaluation criteria:

A test substance with an IVIS ≥ 55.1 is regarded as severe irritant/corrosive and labelled Category 1/R 41.

Historical Control Data:

The result of the positive control fell within the two standard deviations of the current historical mean. Therefore, the assay is considered to be valid.

 

 

RESULTS

Table 1: Opacity values

Parameter	Initial opacity	Final opacity	Opacity change	Mean opacity change of NC	Corrected opacity change	Mean opacity value
Negative control (NC)	5	5	0	-0.33	-	-
	5	5	0
	5	4	-1
Test substance	4	19	15	-	15.33	18.00
	5	21	16		16.33
	4	26	22		22.33
Positive control	5	171	166	-	166.33	174.67
	6	197	191		191.33
	5	171	166		166.33

Table 2: Permeability values (optical density (OD) at 490 nm)

Parameter	OD490 change	Mean OD490 change of NC	Corrected OD490 change	Mean OD490 value
Negative control (NC)	0.008	0.007	-	-
	0.006
	0.006
Test substance	0.004	-	-0.003	-0.001
	0.005		-0.002
	0.008		0.001
Positive control	2.035	-	2.028	1.902
	1.854		1.847
	1.837		1.830

Table 3: In-Vitro Irritancy Score (IVIS) values

	IVIS	Mean IVIS
Test substance	15.285	17.99
	16.3
	22.345
Positive control	196.75	203.20
	219.035
	193.78

Since the test substance resulted in an IVIS value < 55.1, it is not regarded as severe irritant/corrosive.

Applicant's summary and conclusion

Interpretation of results:

other: not corrosive

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

There is regulatory acceptance in the EU that a substance can be considered as severe eye irritant (Serious eye damage Category 1/R41) based on a positive result in the Bovine Corneal Opacity and Permeability (BCOP) test. Negative in-vitro corrosivity responses are not conclusive with respect to non-classification or classification as irritant (Category 2/R36) and shall therefore be subject to further evaluation.