Tungsten disilicide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

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)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Tungsten disilicide

EC Number:

234-909-0

EC Name:

Tungsten disilicide

Cas Number:

12039-88-2

Molecular formula:

Si2W

IUPAC Name:

Tungsten disilicide

Test material form:

solid: particulate/powder

Test animals / tissue source

Species:

cattle

Test system

Vehicle:

other: corn oil

Controls:

yes, concurrent vehicle

Amount / concentration applied:

750 μL tungsten disilicide (suspension) at 20% (w/v) concentration in corn oil.

Duration of treatment / exposure:

Post application the corneas were incubated for approximately 4 h at 32 ºC.

Number of animals or in vitro replicates:

Four sets each consisting of three corneas were tested.

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Value:

0.4

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The IVIS score for the corneas treated with 750 μL tungsten disilicide (suspension) at 20% (w/v) concentration in corn oil were found to be 0.40.
Based on the results of this study, an indication of the classification for tungsten disilicide is as follows:
Classification (OECD 437) : No Category

Executive summary:

EXECUTIVE SUMMARY:This study was conducted to evaluate theocular irritancy of tungsten disilicidein compliance with the OECD437 for theBCOP test.

Four sets each consisting of three corneas were tested. The first set served as control and was treated with750 μLnormal saline. The second set served as positive control and was treated with750 μL20% (w/v) imidazole innormal saline. Test item was found to be insoluble and did not form a homogenous suspension in water. Test item formed a homogenous suspension in corn oil, so the same was selected as vehicle for the treatment.One set was treated with corn oil and served as vehicle control while other set was treated with750 μLtungsten disilicide(suspension) at 20% (w/v) concentration in corn oil.Post application the corneas were incubated for approximately 4 h at32 ºC.At the end of the incubation period reading for opacity were taken.

Post opacity reading permeability was measured by applying1 mL of fluorescein sodium solution (5 mg/mL)on to the anterior surface of the cornea and was incubated forapproximately90 min at32 ºC. At the end of the incubation period Optical Density (OD) was measured at 490 nm for the fluid collected from the posterior chamber.

The meanIn-VitroIrritancy Score(IVIS) ofnormal saline, corn oiland750 μL20% (w/v) imidazole innormal saline(positive control)treated corneaswere found to be 0.98, 1.10 and 124.17,respectively. The IVIS score for the corneas treated with750 μLtungsten disilicide(suspension) at 20% (w/v) concentration in corn oil was found to be 0.40.

Based on the results of this study, an indication of the classification fortungsten disilicideis as follows:

Classification (OECD 437)                                                   :          No Category

COMPLIANCE:Signed and dated GLP and Quality Assurance statements are provided. There was no deviation from regulatory requirements.