Beryllium oxide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-01-25 to 2010-02-04

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to OECD 437 without deviations and fully GLP compliant.

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 437: Bovine opacity and permeability test method for identifying ocular corrosives and severe irritants (September 2009)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Beryllium oxide

EC Number:

215-133-1

EC Name:

Beryllium oxide

Cas Number:

1304-56-9

Molecular formula:

BeO

IUPAC Name:

oxoberyllium

Details on test material:

- Name of test material (as cited in study report): beryllium oxide powder
- Substance type: Powder
- Physical state: Solid
- Analytical purity: 99.9 %
- Lot/batch No.: UOX Lot-No 1846-B; Batch No. 0000690266
- Expiration date of the lot/batch: Not applicable
- Stability under test conditions: Stable under storage conditions
- Storage condition of test material: At room temperature (range of 20 ± 5 °C, provided by Harlan Laboratories Ltd.), light protected

Test system

Vehicle:

physiological saline

Remarks:

0.9 % (w/v) NaCl

Amount / concentration applied:

Prior to the application the test item was suspended in saline (20% (w/v)). 0.75 mL of a 20 % (w/v) solution of the test item were applied to the isolated corneas

Duration of treatment / exposure:

The corneas were exposed to the test item for 4 hours.

Details on study design:

Corneas were treated with the test item solution. After 4 hour treatment at 32 ± 2 °C the opacity of the corneas was determined.After the test item or control items, respectively, were rinsed off from the application side by changing cMEM several times, fresh cMEM was replaced in both compartments and opacity was measured (t240).
In the second step of the assay permeability of the cornea possibly caused by the test item was determined. Fresh complete medium was added to the posterior compartment and 1 mL of a Na-fluorescein solution, 0.5 % (w/v) dissolved in HBSS (Hank’s buffered salt solution) was placed in the anterior compartment. Corneae were incubated again in a horizontal position for further 90 minutes at 32 ± 2 °C in the water-bath. The optical density of an aliquot of the mixed complete medium from the posterior chamber was measured spectrophotometrically at 490 nm (OD490).

Following to the opacity readings, the permeability endpoint was measured as an indication of the integrity of the epithelial cell sheets. After the final opacity measurement was performed, the complete medium was removed from the anterior compartment and replaced by 1 mL of a 0.5% (w/v) fluorescein solution in HBSS. Corneae were incubated again in a horizontal position for 90 minutes in a water-bath at 32 ± 2 °C. Complete medium from the posterior compartment was removed with a 5 mL-syringe, well mixed and the optical density at 490 nm (OD490) was determined with a spectrophotometer.

Results and discussion

In vivo

Irritant / corrosive response data:

With the negative control (0.9% NaCl solution) neither an increase of opacity nor permeability of the corneae could be observed. The positive control (10 % (w/v) Benzalconium chloride) showed clear opacity and distinctive permeability of the corneae and therefore, is classified as very severe eye irritant.

The test item BeO Powder caused opacity of the corneae compared with the results of the negative control, while the permeability of the corneae did not change. The calculated mean in vitro score was 6.69 and therefore, the test item was classified as mild eye irritant.

Any other information on results incl. tables

In Vitro Score Calculation:

The following formula was used to determine the in vitro score of the negative control:

In vitro Score = opacity value + (15 x OD490 value)

The following formula was used to determine the in vitro score of the positive control and the

test item:

In vitro Score = (opacity value – opacity value mean negative control) + (15 x corrected OD490 value)

The in vitro score was calculated for each individual treatment and positive control cornea. The mean in vitro score value of each treated group was calculated from the individual in vitro score values.

Table 2: Results after 240 Minutes Incubation Time

Test Group	Opacity value = Difference (t240-t0) of Opacity^*		Permeability at 490 nm (OD490)^*		In vitro Score	Meanin vitroScore	Proposed in vitro Irritation Scale
		Mean		Mean
Negative Control	0	-0.33	0.066	0.056	0.99	0.50	Non eye irritant
Negative Control	-1		0.052		-0.22
Negative Control	0		0.049		0.74
Positive Control	126.33*		0.212*		129.52	120.39	Very severe eye irritant
Positive Control	113.33*		0.273*		117.43
Positive Control	111.33*		0.192*		114.22
BeO Powder	16.33*		-0.007*		16.23	6.69	Mild eye irritant
BeO Powder	2.33*		0.005*		2.41
BeO Powder	1.33*		0.006*		1.43

*corrected values

Applicant's summary and conclusion

Interpretation of results:

other: mildly irritating

Remarks:

Criteria used for interpretation of results: other: according to OECD 437: Bovine opacity and permeability test method for identifying ocular corrosives and severe irritants (September 2009)

Conclusions:

In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item BeO powder is considered to be a mild eye irritant.

Executive summary:

This in vitro study was performed to assess the corneal irritation and damage potential of BeO Powder by means of the BCOP assay using fresh bovine corneae. After a first opacity measurement of the fresh bovine corneae (t0), the 20 % (w/v) suspension in saline (0.9 % (w/v) NaCl in deionised water) of the test item BeO Powder, the positive, and the negative controls were applied to corneae and incubated for 240 minutes at 32 ± 2 °C.

The posterior chamber contained MEM medium supplemented with sodium bicarbonate and L-glutamine and 1 % fetal calf serum (FCS) (complete medium = cMEM). After the incubation phase the test item, the positive, and the negative controls were each rinsed from the corneae and opacity was measured again (t240). After the opacity measurements permeability of the corneae was determined while application of 1 mL of a fluorescein solution for 90 minutes at 32 ± 2 °C in a horizontal position.

The liquid coming out was measured spectrophotometrically. With the negative control (0.9 % NaCl solution) neither an increase of opacity nor permeability of the corneae could be observed. The positive control (10 % (w/v) Benzalconium chloride) showed clear opacity and distinctive permeability of the corneae and therefore, is classified as very severe eye irritant. The test item BeO Powder caused opacity of the corneae compared with the results of the negative control, while the permeability of the corneae did not change.

The calculated mean in vitro score was 6.69 and therefore, the test item was classified as mild eye irritant.

In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item BeO powder is considered to be a mild eye irritant.