Reaction mass of disodium oxide and zirconium dioxide and silicon dioxide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 Apr 2010 - 14 Apr 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP-Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 437: Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants (07 Sep 2009)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of silicon dioxide and zirconium dioxide

EC Number:

910-388-1

Molecular formula:

not applicable (multi-constituent substance)

IUPAC Name:

Reaction mass of silicon dioxide and zirconium dioxide

Details on test material:

- Name of test material (as cited in study report): Silica-Zirkonia Filler
- Physical state: White powder
- Batch: IT-253
- Analytical purity of components: 72.4% silicon dioxide (CAS No. 7631-86-9) and 26.0% zirconium dioxide (CAS No. 1314-23-4) and a not stated percentage of disodium oxide (CAS No. 1313-59-3)
- Storage: at room temperature in the dark
- Stability: stable under storage conditions
- Expiry date: 20 Nov 2010
- not soluble in water

Test animals / tissue source

Species:

other: bovine eye

Strain:

not specified

Test system

Vehicle:

physiological saline

Controls:

yes, concurrent vehicle

Amount / concentration applied:

750 µL of a 20% (w/w) suspension (in saline from Merck, Germany) of the test material, the vehicle control or the positive control were introduced onto the epithelium of the cornea and uniformously distributed over the entire cornea.

Negative control: physiological saline (Merck, Germany)
Positive control: 20% (w/w) Imidazole (Merck Schuchardt DHG, Germany, CAS No. 288-32-4) solution prepared in physiological saline

Duration of treatment / exposure:

Corneas were incubated in a horizontal position for 240 +/- 10 min at 32 ºC.

Observation period (in vivo):

Measurement directly after incubation

Number of animals or in vitro replicates:

Not applicable, in vitro testing in triplicate

Details on study design:

Bovine eyes were used as soon as possible after slaughter on the same day (slaughterhouse Vitelco, 's Hertogenbosch, The Netherlands). Eyes were transported in physiological saline. Only intact eyes were used. The corneas were isolated and stored at 32 ºC in cell culture medium (cMEM). Each isolated cornea was mounted in a corneal holder of MC2 (Clermont, France) with the endothelial side against the O-ring of the posterior half of the holder. The anterior half of the holder was positioned on top of the cornea and tightened with screws. The compartments of the corneal holder were filled with cMEM and incubated for at least 1 hour at 32 ºC. Thereafter the initial opacity of each cornea was measured with an opacitometer (OP-KIT, MC2, Clermont, France) and recorded. Corneas with an initial opacity > 3 were not used.

After the incubation the solutions were removed and the epithelium was washed at least three times with cMEM. The anterior and the posterior compartement were refilled with fresh cMEM and an opacity determination was performed without any further incubation. After the completion of the incubation period each cornea were inspected visually for dissimilar opacity patterns and the opacity determination was performed. Permeability of the cornea was evaluated using 5 mg/mL sodium fluorescein in the anterior compartment. After 90 minutes incubation time the amount of fluorescein that crosses into the posterior compartment was measured by UV/VIS spectrophotomerty as optical density at 490 nm (OD490).

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

other: mean in vitro irritation score (IVIS)

Basis:

other:

Time point:

other: negative control (physiol. saline)

Score:

0

Remarks on result:

other: mean opacity value + (15 x mean OD490 value)

Results 2

Irritation parameter:

other: mean in vitro irritation score

Basis:

other:

Time point:

other: test substance (20% solution in physiol. saline)

Score:

2

Remarks on result:

other: mean opacity value + (15 x mean OD490 value)

Results 3

Irritation parameter:

other: mean in vitro irritation score

Basis:

other:

Time point:

other: positive control (20% imidazole)

Score:

106

Remarks on result:

other: mean opacity value + (15 x mean OD490 value)

Irritant / corrosive response data:

The treated corneas showed opacity values ranging from 1 to 3 and permeability values ranging from 0 to 0.009. The corneas were clear after the 240 minutes exposure. Hence, the in vitro irritancy scores ranged from 1 to 3 after 240 minutes of treatment.
The laboratories historical control values collected in a period of July 2008 to October 2009 ranged from 0 to 1 for opacity, from -0.007 to 0.009 for permeability and from -0.1 to 1.1 for In vitro Irritancy Score. The values for the test material (tested as 20% solution) were slightly outside the historical control range.

Any other information on results incl. tables

Table 1: Summary of opacity, permeability and in vitro scores

	Mean Opacity	Mean Permeability	Mean In vitro Irritation Score^1,2
Negative control (physiol. saline)	0	0.000	0
Test material (20% (w/w) suspension in physiol. saline	2	0.003	2
Positive control (20% (w/w) Imidazole in physiol. saline)	76	1.998	106

¹Calculated using the negative control mean opacity and mean permeability values.

²In vitro irritancy score (IVIS) = mean opacity value + (15 x mean OD₄₉₀value).

Applicant's summary and conclusion

Interpretation of results:

other: Since the mean in vitro irritancy score for the test substance was below 55.1 after 240 minutes treatment, the test substance is considered to be neither corrosive nor severely irritating.

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

According to OECD Guideline 437, the tested substance was neither corrosive nor severely irritating, as the IVIS was found to be < 55.1.