Potassium niobate

Endpoint summary

Description of key information

Skin Irritation/Corrosion:

In a in vitro skin corrosion study conducted according to OECD guideline 439, the EpiDerm™-Skin Model was topically exposed to Potassium niobate (Purity > 99.8 %) for 3 mins and 60 mins. Corrosive potential of the test item was predicted from the relative mean tissue viabilities obtained compared to the corresponding negative control tissues concurrently treated with DPBS. The test item showed no corrosive effects. The mean relative tissue viability (% negative control) was > 50% (88.3%) after 3 min treatment and > 15% (91.4%) after 60 min treatment. Based on this result, the test item is classified as a non-irritant according to the UN GHS.

In a primary dermal irritation study conducted according to OECD guideline 439, the EpiDerm™-Model (EPI-200 -SIT) was topically exposed to Potassium niobate (Purity > 99.8 %) for 60 mins and 42 h post incubation period. Irritant potential of the test item was predicted from the relative mean tissue viabilities obtained compared to the corresponding negative control tissues concurrently treated with DPBS. The mean relative tissue viability (% negative control) was > 50% (89.7 %). Based on this result, the test item is classified as a non-irritant according to the UN GHS.

 

Eye Irritation:

The eye irritation potential of potassium niobate ( ≥ 99.8% purity) was investigated in the bovine cornea opacity and permeability assay in accordance to OECD 437 (BCOP). The test item was suspended with 0.9% NaCl to gain a 20% concentration. The corneal opacity was measured before and after treatment (4 hours). The mean in vitro irritation score was determined with 14.93. The positive control induced the appropriate responses, indicating the validity of the assay. Based on the results obtained, potassium niobate can not be classified and further testing in another suitable method was required.

In a subsequent primary eye irritation study, according to OECD 405, 0.1 g of the test item of purity ≥ 99.8% was instilled into the conjunctival sac of one eye of three male New Zealand White rabbits. The treated eye was rinsed with physiological saline 1 hour after the application. The untreated eye served as control. Control and treated animals were observed for a period of up to 9 days (until full reversibility of effects). 2 of 3 tested animals had an iritis score of ≥ 1 (mean value of 24, 48, 72h reading). In this study, the test item is an eye irritant under the UN GHS “Category 2.”

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-09-11 to 2017-10-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Version / remarks:

Adopted 29th July, 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

The EpiDerm Skin Model is a well-established organotypic, three-dimensional model of the human epidermis and is used for in vitro experiments since many years. It is known for its similarity to human skin.

Vehicle:

water

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm^TM
- Tissue bach number(s): 20171402

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: room temperature
- Temperature of post-treatment incubation (if applicable): MTT assay plate incubated at 37+/- 1 °C

EpiDerm Kit:
The EpiDerm^TM tissues were provided as kits (e.g. EPI-200; MatTek), consisting of the following components relevant for this study:
1x sealed plate containing e.g. 24 reconstructed epidermis units (area: 0.63 cm2); each reconstructed epidermis is attached to a cell culture insert and maintained on nutritive agar for transport (Lot: 25841)
2x 24-well plates
4x 6-well plates
1x bottle of assay medium (DMEM-based medium; Lot: 090717TMC)
1x bottle of DPBS Rinse Solution (Lot: 062717MGKA)
25 pieces Nylon Mesh circles (8 mm diameter, 200 µm pore)

REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: Using a wash bottle, the tissue will be gently rinsed about 20 times with PBS (phosphate buffered saline) to remove any residual test item


MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT stock solution with 5 mg/mL MTT in PBS, diluted 1 + 4 with DMEM-based medium (final concentration: 1 mg/mL)
- Incubation time: 1h
- Spectrophotometer: plate spectrophotometer
- Wavelength: 570 nm

NUMBER OF INDEPENDENT TESTING RUNS / EXPERIMENTS TO DERIVE FINAL PREDICTION:
The test is performed on a total of 4 tissues per dose group, 2 replicas for each treatment period (3 min and 60 min exposure time).

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERNCE
- killed tissue
- N. of replicates: two tissues per treatment period were treated with 25 mg of the test item (KT) and two killed tissues were left untreated
- Method of calculation used: The non-specific colour of additional killed tissues (NSCkilled) was calculated according to: NSCkilled [%] = [ODTKT/ODNK]*100
The true tissue viability is then calculated as the percent tissue viability obtained with living tissues minus NSMTT minus NSCliving plus NSCkilled.

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
A test item is classified as non-corrosive if both of the following statements hold true: mean tissue viability after 3 min and 60 min treatment is not decreased to less than 50% and 15% of the corresponding negative control tissues, respectively.
A test item is classified corrosive (C, in accordance with UN GHS category 1) in any case, if the mean tissue viability after 3 min treatment is decreased below 50%: if viability is reduced to less than 50% after 3 min treatment and to more than 15% after 60 min treatment. A test item which decreases viability below 25% after 3 min treatment is classifed as corrosive in accordance with optional UN GHS sub-category 1A.

Control samples:

yes, concurrent negative control

yes, concurrent vehicle

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Name: Potassium niobate
- Batch No.: 20171402
- CAS No.: 12030-85-2
- Aggregate state at RT: solid powder
- Colour: white
- Storage conditions: RT, stored in tightly closed container
- Expiry Date: 22 August 2019


- Amount(s) applied (volume or weight with unit): 25 mg of the test substance mixed per 1 mL MTT medium was applied directly atop the EpiDerm^TM tissue.

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL distilled water

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL 8 N KOH

Duration of treatment / exposure:

3 min and 60 min
20 sec. betweeen dosin

Duration of post-treatment incubation (if applicable):

3 h MTT incubation period

Number of replicates:

2 tissues per dose group and time point

Irritation / corrosion parameter:

% tissue viability

Remarks:

3 mins exposure

Run / experiment:

Mean of replicates

Value:

88.3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Irritation / corrosion parameter:

% tissue viability

Remarks:

60 minutes exposure

Run / experiment:

Mean of replicates

Value:

91.4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions, the test item showed no corrosive effects to the skin. The relative mean tissue viability after 3 min 60 min of exposure was > 50%. The test item is therefore considered "non-corrosive” in accordance with UN GHS.

Executive summary:

In a skin corrosion study conducted according to OECD guideline 431, the EpiDerm™-Model was topically exposed to Potassium niobate (Purity > 99.8 %) for 3 mins and 60 mins. Corrosive potential of the test item was predicted from the relative mean tissue viabilities obtained compared to the corresponding negative control tissues concurrently treated with DPBS. The mean relative tissue viability (% negative control) was > 50% (88.3%) after 3 min treatment and > 15% (91.4%) after 60 min treatment. Based on this result, the test item is classified as a non-corrosive according to the UN GHS..

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-10-23 to 2017-11-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 28 Jul. 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

The EpiDerm Skin Model is a well-established organotypic, three-dimensional model of the human epidermis and is used for in vitro experiments since many years. It is known for its similarity to human skin.

Vehicle:

other: Dulbecco´s phosphate buffered saline (DPBS)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDermTM
- Tissue batch number(s): 20171402
- Production date:

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: room temperature
- Temperature of post-treatment incubation (if applicable): MTT assay plate incubated at 37+/- 1 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: Tissue are washed by filling and emptying the inserts 15 times with DPBS and shaken to remove rests of the test item.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT stock solution with 5 mg/mL MTT in PBS, diluted 1 + 4 with DMEM-based medium (final concentration: 1 mg/mL)
- Incubation time: 3 h
- Spectrophotometer: plate spectrophotometer
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- Killed tissues
- N. of replicates : 3
- Method of calculation used: The non-specific colour of additional killed tissues (NSCkilled) was calculated according to:
NSCkilled [%] = [ODTKT/ODNK]*100

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be irritant to skin in accordance with regulation EC 1272/2008 (UN GHS "Category 2") if the viability after exposure and post-incubation is less or equal to 50%.
- The test substance is considered to be non-irritant to skin in accordance with regulation EC 1272/2008 (UN GHS "No Category") if the viability after exposure and post-incubation is more than 50%.

Control samples:

yes, concurrent negative control

yes, concurrent vehicle

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Name: Potassium niobate
- Batch No.: 20171402
- CAS No.: 12030-85-2
- Aggregate state at RT: solid powder
- Colour: white
- Storage conditions: RT, stored in tightly closed container
- Expiry Date: 22 August 2019

- Amount(s) applied (volume or weight with unit): 25 mg

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 30 μL DPBS
POSITIVE CONTROL
- Amount(s) applied (volume or weight): 30 μL 5% SDS solution

Duration of treatment / exposure:

35 min and 60 min
1 min between dosing

Duration of post-treatment incubation (if applicable):

42 h

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

mean

Value:

89.7

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: if mean obsolute OD 570nm of the three negative control tissues is ≥ 0.8 and ≤ 2.8
- Acceptance criteria met for positive control: if mean relative tissue viability of the three positive cpntrol tissues is ≤ 20%
- Acceptance criteria met for variability between replicate measurements: standars deviation (SD) of relative tissue viability obtained from each three concurrently tested tissues is ≤ 18%

Table 2: Result of the Test Item Potassium niobate

Name	Negative control			Positive control			Test Item
Tissue	1	2	3	1	2	3	1	2	3
Absolute OD570	1.625 1.644	1.601 1.592	1.495 1.528	0.114 0.113	0.084 0.084	0.088 0.088	1.496 1.526	1.423 1.430	1.333 1.325
OD570 (Blank Corrected)	1.581 1.600	1. 557 1.548	1.451 1.484	0.070 0.069	0.040 0.040	0.044 0.044	1.452 1.482	1.379 1.3860	1.289 1.281
Mean OD570 of the Duplicates (Blank Corrected)	1.591	1.552	1.467	0.07	0.04	0.044	1.467	1.383	1.285
Total Mean OD570 of 3 replicate tissues ( Blank corected)	1.537*			0.051			1.378
SD 0D570	0.063			0.016			0.091
Relative Tissue Viability (%)	103.5	101	95.5	4.5	2.6	2.9	95.5	90	83.6
Mean Relative Tissue Viablity (%)	100			3.3**			89.7
SD Tissue Viability (%)***	4.1			1			5.9
CV (% viabilities)	4.1			31.3			6.6

* Blank-corrected mean OD 570 nm of the negative control corresponds to 100% absolute tissue viability

** Mean relative tissue viabilitx of the three positive control tissues is ≤ 20%

*** Standard deviation (SD) obtained from the three concurrently tested tissues is ≤ 18%

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions, Potassium niobate showed no irritant effects. The relative mean tissue viability after 60 min of exposure and 42 h post-incubation was > 50%. The test item is therefore classified as “non-irritant” in accordance with UN GHS “No Category”.

Executive summary:

In a primary dermal irritation study conducted according to OECD guideline 439, the EpiDerm™-Model (EPI-200 -SIT) was topically exposed to Potassium niobate (Purity > 99.8 %) for 60 mins and 42 h post incubation period. Irritant potential of the test item was predicted from the relative mean tissue viabilities obtained compared to the corresponding negative control tissues concurrently treated with DPBS. The mean relative tissue viability (% negative control) was > 50% (89.7 %). Based on this result, the test item is classified as a non-irritant according to the UN GHS.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-12-12 to 2018-03-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

Adopted, 9th October 2017

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, 97633 Sulzfeld, Germany
- Age at study initiation: animal no. 1 approximately 35 weeks old, animal no. 2 approximately 36 weeks old and animal no. 3 approximately 37 weeks old
- Weight at study initiation: 3.8 – 4.3 kg
- Housing: - Housed in ABS-plastic or Noryl rabbit cages, floor 4200 cm2
- Diet (e.g. ad libitum): Yes
- Water (e.g. ad libitum): Yes
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 + / - 3
- Humidity (%): 55 + / - 10
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 / 12

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 g

Duration of treatment / exposure:

The test item was applied at a single dose in the conjunctival sac of one eye of each test animal after pulling the lower lid away from the eyeball. The lids were then gently held together for about 1 second in order to prevent loss of the material.

Observation period (in vivo):

up to 9 days

Duration of post- treatment incubation (in vitro):

N.A.

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Yes with physiological saline 0.9% NaCl
- Time after start of exposure: 1 hour after the application

SCORING SYSTEM: Eye irritation scores according to Draze

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible within: 24 h

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 6 d

Remarks on result:

positive indication of irritation

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

fully reversible

Remarks on result:

positive indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 24h

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1.33

Max. score:

4

Reversibility:

fully reversible within: 7 d

Remarks on result:

positive indication of irritation

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.33

Max. score:

4

Reversibility:

fully reversible within: 4 d

Remarks on result:

positive indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.67

Max. score:

3

Reversibility:

fully reversible within: 72 h

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 8 d

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.67

Max. score:

3

Reversibility:

fully reversible within: 9d

Other effects:

No systemic changes or body weight changes were observed. However, local changes were observed.

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Conclusions:

In an in vivo acute eye irritation/corrosion study in rabbits, the test item was classified as an irritant under the GHS Criteria "Category 2."

Executive summary:

In a primary eye irritation study, 0.1 g of the test item of purity ≥ 99.8% was instilled into the conjunctival sac of one eye of three male New Zealand White rabbits (obtained from Charles River Deutschland, 35, 36 and 37 weeks old respectively, 3.8 – 4.3 kg) for about one second. The treated eye was rinsed with physiological saline 1 hour after the application. The untreated eye served as control. Control and treated animals were observed for a period of 9 days. Irritation was scored by the method of Draize. All effects were reversible within 9 days after application.

Conjunctival redness, chemosis and iritis were observed with the highest score of 2, 1.33, and 1, respectively. 2 of 3 tested animals had an iritis score of ≥ 1, meeting the UN GHS for “Category 2A” for eye irritating effects.

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-08-24 to 2017-12-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)

Version / remarks:

adopted 26th July 2013

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

cattle

Strain:

not specified

Remarks:

BCOP

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: uses isolated corneas obtained as a by-product from animals freshly slaughtered at the abattoir A. Moksel AG, Buchloe, Germany

Vehicle:

physiological saline

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 750 µL
- Concentration (if solution): test item was suspended with 0.9% NaCl to gain a 20% concentration.

VEHICLE
- Amount(s) applied (volume or weight with unit):
- Concentration (if solution): 20%
- Lot/batch no. (if required): 17264409
- Purity: 0.9% NaCl
- Expiry date: 2017-11-15
- Source: B. Braun Melsungen AG, Carl-Braun-Str. 1, 34121 Melsungen, Germany

OTHER MATERIALS
- Imidazole (Sigma, lot no. SLBL7984V, expiry date: 30/11/2017)
- RPMI 1640 without phenol red
- Fetal bovine serum (FBS)
- L-glutamine
- Minimum essential medium (MEM) with phenol red (used for the rinsing of test substances only)
- Hanks’ balanced salt solution (HBSS) with Ca++ and Mg++ containing penicillin/ streptomycin
- Sodium fluorescein

Duration of treatment / exposure:

4h ± 5 minutes at 32 ± 1 °C

Duration of post- treatment incubation (in vitro):

Opacity measurements were performed before and directly after exposure.
The optical density at 490 nm was measured upon 90 minutes of incubation with fluorescein after exposure to the test item by using a spectrophotometer.

Number of animals or in vitro replicates:

Three corneas each for potassium niobate, negative control (physiological saline 0.9% NaCl) and positive control (20 % imidazole in physiological saline 0.9 NaCl%).

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): at least three times with MEM (containing phenol red)
- Time after start of exposure: 4h ± 5 minutes

SCORING SYSTEM:
In vitro irritation score (IVIS) = mean opacity value + (15x mean permeability OD490 value)
The IVIS cut-off values for identifiying test substances as inducing serious eye damage (UN GHS Category 1) and test substances not requiring classification for eye irritation of serious eye damage (UN GHS No Category):
IVIS: ≤ 3 - UN GHS: No Category
IVIS: > 3 - ≤ 55 - UN GHS: No prediction can be made
IVIS: > 55 - UN GHS: Category 1

TOOL USED TO ASSESS SCORE:
Opacity measurement was performed with an opacitometer

Irritation parameter:

in vitro irritation score

Run / experiment:

Mean of replicates

Value:

14.93

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

not determinable

Table 1: Opacity

Cornea No.	Test item	Initial opacity	Final opacity	Change of opacity value	Corrected opacity value
1	Negative Control	0.73	1.36	0.63
2		0.39	0.49	0.10
3		0.52	1.19	0.66
MV		0.55	1.01	0.46
4	Positive Control	1.15	98.20	97.05	96.59
5		1.19	84.99	83.81	83.34
6		1.26	100.26	99.01	98.54
MV		1.20	94.49	93.29	92.82
7	Test Item	-0.18	11.74	11.92	11.45
8		-0.11	17.623	17.73	17.27
9		-0.35	16.19	16.53	16.07
MV		-0.21	15.18	15.39	14.93

MV = Mean value

Table 2: Permeability

Cornea No.	Test item	OD490	Corrected OD490 Value
1	Negative Control	0.012
2		0.010
3		0.006
MV		0.009
4	Positive Control	2.110	2.101
5		1.745	1.736
6		1.443	1.434
MV		1.766	1.757
7	Test Item	0.010	0.001
8		0.008	-0.001
9		0.013	0.004
MV		0.010	0.001

Table 3: In Vitro Irritation Score

Cornea No.	Test item	Corrected Opacity	Corrected OD490 Value	IVIS
1	Negative Control	0.63	0.012
2		0.10	0.010
3		0.66	0.006
MV		0.46	0.009	0.60
4	Positive Control	96.59	2.101
5		83.34	1.736
6		98.54	1.434
MV		92.82	1.757	117.17
7	Test Item	11.45	0.001
8		17.27	-0.001
9		16.07	0.004
MV		14.93	0.001	14.94

Table 4: Historical mean In Vitro Irritation Score of the Positive Control

	IVIS Positive Control – Imidazole 20%
Mean Value (MV)	124.00
Standard Deviation (SD)	17.90
MV – 2x SD	88.20
MV + 2x SD	159.81
Number of Replicates providing Historical Mean: 29

Interpretation of results:

study cannot be used for classification

Conclusions:

No prediction can be made regarding the classification of the test substance Potassium niobate according to the evaluation criteria. Further testing in another suitable method is required.

Executive summary:

The eye irritation potential of potassium niobate ( ≥ 99.8% purity) was investigated in the bovine cornea opacity and permeability assay in accordance to OECD 437. The test item was suspended with 0.9% NaCl to gain a 20% concentration. The corneal opacity was measured before and after treatment (4 hours). The mean in vitro irritation score was determined with 14.93. The positive control induced the appropriate responses, indicating the validity of the assay. Based on the results obtained, potassium niobate can not be classified and further testing in another suitable method is required.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the result from a primary eye irritation study, according to OECD guideline 405, potassium niobate needs to classifed as an eye irritant, category 2, H319 according to CLP regulation 1272/2008.