Cesium tungsten oxide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04 Jan 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Adopted 26 Jul 2013

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU method B.47 (Bovine corneal opacity and permeability test method for identifying ocular corrosives and severe irritants)

Version / remarks:

Commission Regulation (EC) No. 440/2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom, London, England

Test material

Test material information

Constituent 1

Test material form:

solid: nanoform, no surface treatment

Test animals / tissue source

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Local abattoir as a by-product from freshly slaughtered animals.
- Characteristics of donor animals: Adult cattle, typically 12 to 60 months old
- Storage, temperature and transport conditions of ocular tissue: Eyes were excised after slaughter and were transported on the same day (of slaughter) over ice packs in Hank's Balanced Salt Solution (HBSS) supplemented with antibiotics.
- Time interval prior to initiating testing: Corneas were prepared immediately on arrival
- indication of any existing defects or lesions in ocular tissue samples: The eyes were free of defects such as scratches, and neovascularization. Prior to testing, corneal opacity was determined by the amount of light transmitted through the cornea via a opacitometer.
- Indication of any antibiotics used: Penicillin 100 IU/mL and streptomycin 100 µg/mL in HBSS.

Test system

Vehicle:

physiological saline

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.75 mL
- Concentration (if solution): 20% (w/v) solution in 0.9% (w/v) sodium chloride

VEHICLE
- Amount applied: 0.75 mL
- Concentration (if solution): 0.9% sodium chloride solution
- Lot/batch no.: Aguettant Ltd. batch number 3011542
- Purity: 0.9%

Duration of treatment / exposure:

240 minutes at 32 ± 1 °C

Observation period (in vivo):

Not applicable

Duration of post- treatment incubation (in vitro):

Not applicable

Number of animals or in vitro replicates:

3

Details on study design:

SELECTION AND PREPARATION OF CORNEAS: Sourced from a local abattoir as a by-product from freshly slaughtered animals.

QUALITY CHECK OF THE ISOLATED CORNEAS: The eyes were visually inspected to be free of defects such as scratches, and neovascularization. Prior to testing, corneal opacity was determined by the amount of light transmitted through the cornea via a opacitometer.

NUMBER OF REPLICATES: 3

NEGATIVE CONTROL USED: 0.9% sodium chloride

POSITIVE CONTROL USED: Imidazole 20% (w/v) in 0.9% (w/v) sodium chloride

APPLICATION DOSE AND EXPOSURE TIME: 0.75 mL for 240 minutes at 32 ± 1 °C

TREATMENT METHOD: closed chamber

POST-INCUBATION PERIOD: no

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: at least three times

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: a post-treatment opacity was measured and each cornea was visually observed prior to incubation with sodium fluorescein
- Corneal permeability: passage of sodium fluorescein dye measured with the aid of [UV/VIS spectrophotometry / microtiter plate reader] (OD490): after 90 minutes at 32 ± 1 °C
- Others: visual observations

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

DECISION CRITERIA: the decision criteria as indicated in the TG was used

Results and discussion

In vitro

Results

Irritation parameter:

in vitro irritation score

Run / experiment:

mean out of all 3 eyes

Value:

14.6

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

not determinable

Other effects / acceptance of results:

- Acceptance criteria:
OECD 437: "A test is considered acceptable if the positive control gives an IVIS that falls within two standard deviations of the current historical mean, which is to be updated at least every three months, or each time an acceptable test is conducted in laboratories where tests are conducted infrequently (i.e., less than once a month). The negative or solvent/vehicle control responses should result in opacity and permeability values that are less than the established upper limits for background opacity and permeability values for bovine corneas treated with the respective negative or solvent/vehicle control. A single testing run composed of at least three corneas should be sufficient for a test chemical when the resulting classification is unequivocal."

- positive control criterion: Imidazole 20% (w/v) was used for positive control purposes. The test was acceptable if the positive control produced an in vitro Irritancy Score which fell within two SD of the historical mean during 2015 for this testing facility. Therefore the in vitro Irritancy score should fall within the range of 50.8 to 100.4.
- negative control criterion: Sodium chloride 0.9% (w/v) was used for negative control purposes. The test was acceptable if the negative control produced an in vitro Irritancy Score which is less than or equal to the upper limit for background opacity and permeability values during 2015 for bovine corneas treated with the respective negative control. When testing solids the negative control for opacity should be ≤ 5.4 and for permeability ≤ 0.070.

IVIS Classification
≤ 3 No Category. Not requiring classification to UN GHS or to EU CLP
> 3; ≤ 55 No prediction on eye irritation can be made.
> 55 Category 1. UN GHS or EU CLP Causes serious eye damage.
____________________________________________________________________________________________________________________________
IVIS Scores

Treatment IVIS Score
Test Item 14.6
Negative Control 1.1 The negative control gave opacity of ≤ 5.4 and permeabilty of ≤0.070, therefore acceptance criteria were satisfied.
Positive Control 93.1 The positive control IVIS was within the range of 50.8 to 100.4, therefore the acceptance criteria were satisfied.

Any other information on results incl. tables

 

Treatment	Cornea Number	Opacity				Permeability (OD)		In Vitro Irritancy Score (IVIS)
		Pre-trmt	Post-trmt	Post - Pre	Corrected		Corrected
Negative Control	1	3	3	0		0.017
	2	3	4	1		0.039
	3	3	4	1		0.024
				0.7*		0.027^@		1.1
Positive Control	4	3	81	78	77.3	1.481	1.454
	5	3	68	65	64.3	1.939	1.912
	6	2	62	60	59.3	1.876	1.849
					67.0^#		1.739^#	93.1
Test Item	7	2	13	11	10.3	0.119	0.092
	8	2	18	16	15.3	0.049	0.022
	9	2	19	17	16.3	0.025	0.000
					14.0^#		0.038^#	14.6

OD = optical density

trmt = treatment

*= mean of the post-treatment – pre-treatment values

^#= mean corrected values

^@= mean permeability

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

No prediction on eye irritation can be made

Executive summary:

The Bovine Corneal Opacity and Permeabilty (BCOP) test was conducted using undissolved test item in accordance with OECD Guideline 437. Test item was suspended in sodium chloride (20 % w/v) and 0.75 mL applied evenly to the surface of three corneas, the test time was 240 minutes . A negative and positive control group, each containing 3 corneas, were also prepared.  Measurements for corneal opacity and corneal permeability were made.  Corneal opacity and corneal permeability media solutions were analysed by a spectrophotometer at 490 nanometers (OD490). The test item did not interfere with result interpretation.   

The resulting in an In Vitro Irritation Score (IVIS) of ~14.  It was concluded that under the condition of this study the test item no prediction could be made in respect of its potential to cause eye irritation, but the test item does not cause eye damage/corrosion.