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Toxicological information

Eye irritation

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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

Constituent 1
Chemical structure
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).

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