Titanium nitride

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-11-03 to 2014-12-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Titanium nitride

EC Number:

247-117-5

EC Name:

Titanium nitride

Cas Number:

25583-20-4

Molecular formula:

NTi

IUPAC Name:

titanium nitride

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Titanium nitride
- Analytical purity: > 99%
- Physical state: solid
- Colour: yellow
- Lot/batch No.: 84958
- Expiration date of the lot/batch: 2016-09-16
- Storage condition of test material: at room temperature

Test animals / tissue source

Species:

other: BCOP

Strain:

not specified

Details on test animals or tissues and environmental conditions:

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

Test system

Vehicle:

physiological saline

Controls:

yes

Amount / concentration applied:

TEST MATERIAL
- 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): 750 µl

Duration of treatment / exposure:

4h ± 5 minutes at 32 ± 1 °C

Observation period (in vivo):

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 titanium nitride, 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 3 times with minimum essential medium (MEM)
- 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

Results and discussion

In vivo

Results

Irritation parameter:

other: In vitro irritation score (IVIS)

Basis:

mean

Remarks:

(triplicates)

Time point:

other: 90 minutes after 4h exposure

Score:

0.03

Max. score:

202

Remarks on result:

other: Max score= mean in vitro irritation score of positive control

Any other information on results incl. tables

Table 1: In Vitro Irritation Score
Cornea No.	Test Item	Corrected Opacity	Corrected OD490 Value	IVIS
1	Negative Control	0.00	0.005
2		1.00	0.009
3		0.00	0.023
MV		0.33	0.012	0.52
4	Positive Control	187.67	1.791
5		174.67	2.019
6		155.67	2.026
MV		172.67	1.945	201.84
7	Test Item	-0.33	-0.001
8		-0.33	0.008
9		0.67	-0.001
MV		0.00	0.002	0.03
MV = mean value

Table 2: Historical mean in vitro irritation score of the positive control
			IVIS (positive control)
Mean Value (MV)			206.77
Standard deviation (SD)			24.53
MV - 2 x SD			157.71
MV + 2 x SD			255.84

IVIS: in vitro irritation score

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: other: UN GHS

Conclusions:

In conclusion, based on the mean in vitro irritation score of 0.03 obtained in the bovine cornea opacity and permeability assay (OECD 437), titanium nitride is considered to be not irritating under the test conditions reported.

Executive summary:

The eye irritation potential of titanium nitride (> 99% 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 0.03. The positive control induced the appropriate responses, indicating the validity of the assay. Based on the results obtained, titanium nitride can be considered as not irritating to the eye ( UN GHS No Category).