lambda4-cerium(4+) zirconium(4+) tetraoxidandiide

Endpoint summary

Description of key information

- Skin irritation: not irritating (conclusion for both nano and bulk forms, should the latter be placed on the market)
- Eye irritation: slightly irritating, not resulting in classification (conclusion for both nano and bulk forms, should the latter be placed on the market))

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 16-OCT-1995 to 08-MAR-1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Elevage Cunicole de Val de Selle, 80160 Prouzel, France
- Age at study initiation: no data
- Weight at study initiation: 2.4 +/- 0.2 kg
- Housing: individually in polystyrene cages (35x55x32 cm or 48.2x58x36.5 cm)
- Diet (e.g. ad libitum): free access to 112 pelleted diet (U.A.R., 91360 Villemoisson-sur-Orge, France)
- Water (e.g. ad libitum): drinking water filtered by a Millipore membrane (0.22 micron), ad libitum
- Acclimation period: at least 5 days before the start of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 +/- 3°C
- Humidity (%): 30 to 70% relative humidity
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12h / 12h

IN-LIFE DATES: From: 15 nov 1995 To: 18 nov 1995

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

other: control on the other untreated flank

Amount / concentration applied:

500 mg

Duration of treatment / exposure:

4 hours

Observation period:

72 hours

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: 500 mg of the substance was applied to a 6 cm2 moistened gauze pad which was thus applied to the right flank of the animals.
- Type of wrap if used: The test item and the gauze pad were held in contact with the skin by means of an adhesive hypoallergenic aerated semi-occlusive dressing and a restraining bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Any residual test item was wiped off by means of a moistened gauze pad.

SCORING SYSTEM: according to EEC Criteria

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Interpretation of results:

GHS criteria not met

Conclusions:

Not irritating to skin.

The reaction mass of cerium dioxide and zirconium dioxide is not classified according to the criteria of the EU-CLP Regulation 1272/2008.

Executive summary:

In a primary dermal irritation study (CIT, 1996), New Zealand White rabbits (3 males) were dermally exposed to 500 mg of the reaction mass of cerium dioxide and zirconium dioxide onto one flank.

Test sites were covered with semi-occlusive dressing for 4 hours. The cutaneous examinations were performed 1, 24, 48 and 72 hours after removal of the dressing. The mean score values for erythema and oedema were calculated for 24, 48 and 72 hours.

No cutaneous reactions were observed during the study.

In this study, the reaction mass of cerium dioxide and zirconium dioxide is not classified according to the EU classification criteria.

Reference 2

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2008-12-02 to 2009-01-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

No information was provided on the initial test or weight of evidence to waive the need for an initial test.

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan UK Limited, Bicester, Oxon, UK
- Age at study initiation: 12-20 weeks
- Weight at study initiation: 2.0 to 3.5 kg
- Housing: individually in suspended cages
- Diet (e.g. ad libitum): ad libitum, 2030 Taklad Global Rabbit diet
- Water (e.g. ad libitum): mains drinking water
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-23
- Humidity (%): 30-70
- Air changes (per hr): 15/hour
- Photoperiod (hrs dark / hrs light): 12/12 (06:00 - 18:00 light)


IN-LIFE DATES: From: no data To: no data

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

water

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g

VEHICLE
- Amount(s) applied (volume or weight with unit): 0.5 mL

Duration of treatment / exposure:

4 hours

Observation period:

1, 24, 48 and 72 hours

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: dorsal/flank
- Type of wrap if used: Cotton gauze patch was used to apply test substances to shorn skin. The patch was secured in position with a strip of surgical adhesive tape. The trunk of each test animal was wrapped in an elasticated corset and the animals were returned to their cages for the duration of the exposure period.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): water soaked cotton wool cloth
- Time after start of exposure: 4 hours

SCORING SYSTEM: Draize (1959) - The scores for erythema and oedema at the 24 and 72-hour readings were totalled for the three test rabbits and this total was divided by six to give the primary irritation index of the test substance.

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24 and 72-hour readings

Score:

0

Max. score:

8

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No evidence of skin irritation was reported under the test conditions.

Other effects:

All test animals showed expected gain in body weight during the study.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the test, the test substance failed to produce an irritation to the skin of the test animals. Under these test conditions it can be stated that the test substance can be classified as not irritating to rabbit skin according to the Draize classification scheme. No corrosive effects were reported.

Reference 3

Endpoint:

skin corrosion: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro skin irritation study does not need to be conducted because adequate data from an in vivo skin irritation study are available

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The in vivo studies with the reaction mass were performed in 1996 and 2009. At this date, the OECD guidelines for in vitro studies were not implemented yet / had not become mandatory.

Reason / purpose for cross-reference:

data waiving: supporting information

Reason / purpose for cross-reference:

data waiving: supporting information

Reference 4

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

November 1982 - February 1983

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Roucher, Couhé France - EGAV, Passais-la-Conception France - Elevage Scientifique des Dombes, Châtillon-sur-Chalaronne France - Gwen Meur, Trégonneau France
- Age at study initiation: not specified
- Weight at study initiation: 2.5 kg +/- 200 g
- Housing: individual polystyrene cages (54 x 36 x 31.5 cm)
- Diet: 150 g pelleted diet/animal/day
- Water: ad libitum
- Acclimation period: at least 8 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 +/- 3
- Humidity (%): 50 +/- 20
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12 / 12 (7.30 am - 7.30 pm)


IN-LIFE DATES: 23 November 1982 (application)

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

other: moistening with 0.1 mL water

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.5 g

Duration of treatment / exposure:

4 hours

Observation period:

14 days

Number of animals:

3 males

Details on study design:

TEST SITE
- Area of exposure: approximately 6 cm² skin surface
- Type of wrap: semiocclusive dressing


REMOVAL OF TEST SUBSTANCE
- Washing: yes
- Time after start of exposure: 4 hours


SCORING SYSTEM:
- Erythema and Eschar Formation:
No erythema -> 0
Very slight erythema (barely perceptible) ->1
Well defined erythema -> 2
Moderate to severe erythema -> 3
Severe erythema (beef redness) to eschar formation preventing grading of erythema -> 4

- Oedema Formation:
No oedema -> 0
Very slight oedema (barely perceptible) -> 1
Slight oedema (edges of area well defined by definite raising) -> 2
Moderate oedema (raised approximately 1 mm) -> 3
Severe oedema (raised more than 1 mm and extending beyond area of exposure) -> 4

- Primary Dermal Irritation Index = (Sum of individual Erythema scores + Sum of individual Edema scores) / 12

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 1, 24, 48, 72 hours

Score:

0

Max. score:

8

Reversibility:

other: not applicable

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Summary table of individual irritation scores

 

Rabbit number	445	446	447	Total	Mean
Erythema score
Time points (h) 1 24 48 72	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0
Oedema score
Time points (h) 1 24 48 72	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0

Interpretation of results:

GHS criteria not met

Conclusions:

Cerium Oxide is not considered to be a skin irritant.

Executive summary:

In a primary dermal irritation study (Institut Français de Toxicologie report No. 302314), 3 male New Zealand White rabbits were dermally exposed to 0.5 g of Cerium Oxide moistened with 0.1 mL water applied on a ~6 cm² skin area maintained under semi-occlusive dressing for 4 hours. Animals then were observed for up to 72 hours. Irritation was scored 1, 24, 48 and 72 h after removal of the dressing by calculating dermal irritation scores, based on the grading of cutaneous erythema and oedema.

 

No signs of cutaneous erythema or oedema were observed. The dermal irritation scores were equal to 0.

 

The test substance was therefore considered as non-irritant to the skin. No classification for skin irritation is warranted based on the absence of cutaneous reactions following a 4-hour exposure, according to the criteria of Annex VI Directive 67/548/EEC or UN/EU GHS.

 

This study is classified as acceptable. It satisfies the OECD 404 guideline requirements for acute dermal irritation or corrosion.

Reference 5

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Not specified

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

EpiDerm skin irritation test (as described by Fallerl et al., 2002; Fentem et al., 2001 or Hartung, 2007).

GLP compliance:

not specified

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: reconstructed human epidermis

Details on animal used as source of test system:

Not applicable

Justification for test system used:

According to Park B et al., the EpiDerm™ EPI-200 human epidermal model from MatTek Corporation (USA) was utilised in their preliminary screening approach for assessment of the safety of the test material since the skin is a potential route of exposure during the formulation and use of the test material containing diesel fuel additive when accidental.
Skin contamination might reasonably be expected to occur.

Vehicle:

not specified

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ EPI-200 human epidermal model from MatTek Corporation (Ashland, MA, USA)
- Tissue batch number(s), production date, shipping date, delivery date, date of initiation of testing: no data available

TEMPERATURE USED FOR TEST SYSTEM
No data available

REMOVAL OF TEST MATERIAL AND CONTROLS
No data available

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
No data available

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
No data available

NUMBER OF REPLICATE TISSUES:
No data available

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
No data available

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION:
No data available

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- Justification for the selection of the cut-off point(s) if different than recommended in TG 431 and 439:
MIP calculation equation: MIP = (ET50 [reference material]) / (ET50 [test material])
MIP values > 0.8 => potential to be an in vivo skin irritant

Control samples:

yes, concurrent negative control

yes, concurrent positive control

other: standard reference material

Amount/concentration applied:

50 mg of test substance applied

Duration of treatment / exposure:

Exposure times: 960, 1200 and 1440 minutes

Duration of post-treatment incubation (if applicable):

Not applicable

Number of replicates:

No data available

Irritation / corrosion parameter:

other: mean irritation potential

Value:

< 0.03

Remarks on result:

other: Basis: mean. Reversibility: no data.

ET50 values for non-nano cerium oxide, 1% (w/v) Triton X-100 (positive control) and 1% of 20% (w/v) SLS (standard reference material) were >1440, 410.60 and 46.22 minutes respectively.

Interpretation of results:

other: not irritating - expert judgement

Conclusions:

Since non-nanoparticular cerium dioxide had a Mean Irritation Potential value < 0.8, it was not considered to have the potential to be an in vivo skin irritant in this in vitro EpiDerm test.

Reference 6

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published data with limited level of details.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

Standard Draize method

GLP compliance:

not specified

Specific details on test material used for the study:

No details provided

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

No details provided

Type of coverage:

occlusive

Preparation of test site:

other: one intact and one abraded site per animal

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.5 g

Duration of treatment / exposure:

24 hours

Observation period:

72 hours

Number of animals:

6

Details on study design:

TEST SITE
- Area of exposure: approx. 2.5 cm²
- Type of wrap if used: occlusive


REMOVAL OF TEST SUBSTANCE
- Washing: test site wiped
- Time after start of exposure: 24 hours


SCORING SYSTEM:
According to the method of Draize (describe in: Draize HH et al. Methods for the study of irritation and toxicity of substances applied topically to the skin and mucous membranes. J. Pharmacol. Exp. Ther. 83: 377-90, 1944)

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 24 and 72 hours

Score:

0

Max. score:

8

Reversibility:

other: not applicable

Interpretation of results:

other: not irritating

Conclusions:

Cerium Oxide is not considered to be a skin irritant.

Reference 7

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1986-03-04 to 1986-07-17

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Well documented, scientifically sound GLP study that was based on the OECD Guideline 404 "Acute Dermal Irritation/Corrosion". The test substance was tested simultaneously on the same animals.

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

substances were tested simultaneously on the same animals

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Regal Rabbits, Great Bookham, Surrey
- Housing: individually in metal grid-floored cages
- Diet: ad libitum, Grain Harvester's special rabbit diet 679
- Water: ad libitum tap water
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-23
- Humidity (%): 43-74

Type of coverage:

occlusive

Preparation of test site:

shaved

Vehicle:

water

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): spread on a patch previously moistened with 0.5 mL of water to ensure good contact with the skin

Duration of treatment / exposure:

4 hours

Observation period:

24, 48 and 72 hours

Number of animals:

4 male animals

Details on study design:

TEST SITE
- Area of exposure: dorsal
- Type of wrap if used: 2.5 cm square patches were applied to the skin on 6 cm square patches of polythene held in place by adhesive tape and elastic net bandages.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): tap water
- Time after start of exposure: 4 hours

SCORING SYSTEM: Draize (1959), indices of irritation were calculated for each animal by totalling the scores for oedema and erythema for each animal and dividing by two.

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24 h

Score:

ca. 0

Max. score:

8

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

48 h

Score:

ca. 0

Max. score:

8

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

72 h

Score:

ca. 0

Max. score:

8

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #4

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #4

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No reaction to the test substances was reported in any of the test animals.

Interpretation of results:

GHS criteria not met

Conclusions:

The test substance was determined to be not irritating to the skin of rabbits.

Reference 8

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Not specified

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Reason / purpose for cross-reference:

reference to same study

Qualifier:

no guideline followed

Principles of method if other than guideline:

EpiDerm 'EPI-200' human epidermal model skin irritation test (as developed in MatTek Corporation, Ashland, MA, USA).

GLP compliance:

not specified

Species:

other: not applicable

Strain:

other: not applicable

Type of coverage:

not specified

Preparation of test site:

not specified

Vehicle:

not specified

Controls:

other: not applicable

Amount / concentration applied:

50 mg of test substance applied

Duration of treatment / exposure:

Exposure times: 960, 1200 and 1440 minutes

Observation period:

No data

Number of animals:

Not applicable

Irritation / corrosion parameter:

other: mean irritation potential

Value:

< 0.01

Remarks on result:

other: Basis: mean calculated as ET50 (reference material) / ET50 (test material). Reversibility: no data. (migrated information)

ET50 values for nano cerium oxide, 1% (w/v) Triton X-100 (positive control) and 1% of 20% (w/v) SLS (standard reference material) were 1517.18, 260.10 and 20.68 minutes respectively.

Interpretation of results:

study cannot be used for classification

Conclusions:

Since nanoparticular cerium dioxide had a Mean Irritation Potential value < 0.8, it was not considered to have the potential to be an in vivo skin irritant in this in vitro EpiDerm test.

Reference 9

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2000-02-08 to 2000-03-23

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented, scientifically sound study with methods similar to OECD guidline 404 with the following deviations: not GLP, no information on environmental conditions, and no mention of untreated areas used as controls.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

Not GLP, no information on environmental conditions, and no mention of untreated areas used as controls.

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Biotech Co., Ltd
- Age at study initiation: 3 months
- Weight at study initiation: 2.91-3.28 kg
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: no data


ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data


IN-LIFE DATES: From: no data To: no data

Type of coverage:

occlusive

Preparation of test site:

not specified

Vehicle:

water

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 g; moistened with distilled water for injection
- Concentration (if solution): no data

VEHICLE
- Amount(s) applied (volume or weight with unit): no data
- Concentration (if solution): no data
- Lot/batch no. (if required): not applicable
- Purity: not applicable

Duration of treatment / exposure:

4 hours

Observation period:

1, 24 and 48 hours after the lint removal.

Number of animals:

3 male animals

Details on study design:

TEST SITE
- Area of exposure: dorsal
- % coverage: no data
- Type of wrap if used: 0.5 g of the test agent was applied to a 2.5 cm square lint (Nankai Sangyou Inc.), and was secured with a piece of White Tape (Nichiban Co., Ltd.). Two application areas were established per animal. Each area was covered with a piece of oilpaper (Amadin Inc.), and the torso was covered by Silkytex (Alcare Co., Ltd.) to protect and secure the lint.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): the area was wiped off with distilled water for injection to remove the test agent
- Time after start of exposure: 4 hours

SCORING SYSTEM: Grades were given based on the Draize scoring method. The skin irritation of the test agent was evaluated according to skin primary irritation evaluation standard of the AFNOR (1982)

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: 1 hour

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

72 h

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

not measured/tested

Remarks:

The last observation was after 48 h, which is acceptable since no signs of irritation were observed in any of the exposed animals.

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: 1 hour

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

72 h

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

not measured/tested

Remarks:

The last observation was after 48 h, which is acceptable since no signs of irritation were observed in any of the exposed animals.

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: 1 hour

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

72 h

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

not measured/tested

Remarks:

The last observation was after 48 h, which is acceptable since no signs of irritation were observed in any of the exposed animals.

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: 1 hour

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #1

Time point:

72 h

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

not measured/tested

Remarks:

The last observation was after 48 h, which is acceptable since no signs of irritation were observed in any of the exposed animals.

Irritation parameter:

edema score

Basis:

animal #2

Time point:

other: 1 hour

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #2

Time point:

72 h

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

not measured/tested

Remarks:

The last observation was after 48 h, which is acceptable since no signs of irritation were observed in any of the exposed animals.

Irritation parameter:

edema score

Basis:

animal #3

Time point:

other: 1 hour

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritation parameter:

edema score

Basis:

animal #3

Time point:

72 h

Max. score:

4

Reversibility:

other: not applicable

Remarks on result:

not measured/tested

Remarks:

The last observation was after 48 h, which is acceptable since no signs of irritation were observed in any of the exposed animals.

Irritation parameter:

primary dermal irritation index (PDII)

Basis:

mean

Time point:

other: 1, 24 and 48 hours

Score:

0

Max. score:

8

Reversibility:

other: not applicable

Remarks on result:

no indication of irritation

Irritant / corrosive response data:

No irritation was observed after 48 hours.

Other effects:

There were no abnormalities in the general condition or the weight changes to any of the 3 animals.

Interpretation of results:

GHS criteria not met

Conclusions:

No irritative reaction was observed during the observation period.

Reference 10

Endpoint:

skin irritation: in vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Justification for type of information:

The in vivo skin irritation studies on nano and bulk cerium dioxide, zirconium dioxide and yttrium zirconium dioxide are considered relevant for supporting the conclusion drawn from the study conducted on the reaction mass of cerium dioxide and zirconium dioxide itself.
The read across justification document is attached to IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Remarks:

The results of the in vivo studies performed with cerium dioxide, zirconium dioxide and yttrium zirconium dioxide were similar to the results obtained with the reaction mass of cerium dioxide and zirconium dioxide. The reaction mass is not expected to cause skin irritation and therefore does not need to be classified for skin irritation or corrosion.

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Remarks on result:

no indication of irritation

Remarks:

The results of the in vivo studies performed with cerium dioxide, zirconium dioxide and yttrium zirconium dioxide were similar to the results obtained with the reaction mass of cerium dioxide and zirconium dioxide. The reaction mass is not expected to cause skin irritation and therefore does not need to be classified for skin irritation or corrosion.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 16-OCT-1995 to 08-MAR-1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Elevage Cunicole de Val de Selle, 80160 Prouzel, France
- Age at study initiation: no data
- Weight at study initiation: 2.5 +/- 0.4 kg
- Housing: individually in polystyrene cages (35x55x32 cm or 48.2x58x36.5 cm)
- Diet (e.g. ad libitum): free access to 112 pelleted diet (U.A.R., 91360 Villemoisson-sur-Orge, France)
- Water (e.g. ad libitum): drinking water filtered by a Millipore membrane (0.22 micron), ad libitum
- Acclimation period: at least 5 days before the start of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 +/- 3°C
- Humidity (%): 30 to 70% relative humidity
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12h / 12h

IN-LIFE DATES: From: 22 nov 1995 To: 29 nov 1995

Vehicle:

unchanged (no vehicle)

Controls:

other: the right eye served as control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 100 mg

Observation period (in vivo):

One hour, 24, 48 and 72 hours after the administration and then daily for 4 days at the latest.
Reversibility of ocular lesions was observed on day 4 (two animals) or 8.

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE: not rinsed
SCORING SYSTEM: according to EEC Criteria
TOOL USED TO ASSESS SCORE: fluorescein

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.7

Max. score:

4

Reversibility:

fully reversible within: 5 days

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 5 days

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 5 days

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Max. score:

2

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.7

Max. score:

2

Reversibility:

fully reversible within: 72 h

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0.3

Max. score:

3

Reversibility:

fully reversible within: 8 days

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 8 days

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

2.3

Max. score:

3

Reversibility:

fully reversible within: 8 days

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 72 h

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 72 h

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 72 h

Other effects:

Clear ocular discharge was observed in 2 rabbits for 24 or 48 hours after administration of the test substance.

Interpretation of results:

GHS criteria not met

Conclusions:

The reaction mass of cerium dioxide and zirconium dioxide was found to be slightly irritating to rabbit eyes, however, the observed effects did not reach the classification limits under the CLP Regulation and therefore the reaction mass is not classified for eye irritation under the CLP Regulation.

Executive summary:

In a primary eye irritation study (CIT, 1996), 100 mg of the reaction mass of cerium dioxide and zirconium dioxide was instilled into the conjunctival sac of the left eye of New Zealand White rabbits (3 animals). Eyes were not rinsed and the right eye served as control. The ocular examinations were performed 1, 24, 48 and 72 hours after instillation.

Mean scores calculated for each animal over 24, 48 and 72 hours were 1.0, 1.0 and 1.3 for chemosis, 0.3, 1.0 and 2.3 for redness of the conjunctivae, 0.0, 0.0 and 0.7 for iris lesions and 0.7, 0.3 and 1.3 for corneal opacity. Total reversibility was observed by day 4 (2 animals) or day 8.

In this study, the reaction mass of cerium dioxide and zirconium dioxide is not classified as eye irritant based on the EU classification criteria.

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

an in vitro eye irritation study does not need to be conducted because adequate data from an in vivo eye irritation study are available

Reason / purpose for cross-reference:

data waiving: supporting information

Reference 3

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

November 1982

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Roucher, Couhé France - EGAV, Passais-la-Conception France - Elevage Scientifique des Dombes, Châtillon-sur-Chalaronne France - Gwen Meur, Trégonneau France
- Age at study initiation: not specified
- Weight at study initiation: 2.5 kg ± 200 g
- Housing: individual polystyrene cages (54 x 36 x 31.5 cm)
- Diet: 150 g pelleted diet/animal/day
- Water: ad libitum
- Acclimation period: at least 8 days

ENVIRONMENTAL CONDITIONS
- Temperature: 20 ± 3°C
- Humidity: 50 ± 20%
- Air changes: 12 per hr
- Photoperiod: 12 hrs dark / 12 hrs light (7.30 am - 7.30 pm)

IN-LIFE DATES: 25 November 1982 (instillation)

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.1 g

Duration of treatment / exposure:

Single conjunctival instillation

Observation period (in vivo):

7 days

Number of animals or in vitro replicates:

3 males

Details on study design:

REMOVAL OF TEST SUBSTANCE
- No washing

SCORING SYSTEM:
- Conjunctivae
* Chemosis: Swelling (refers to lids and/or nictating membranes)
Normal -> 0
Some swelling above normal -> 1
Obvious swelling, with partial eversion of lids -> 2
Swelling, with lids about half closed -> 3
Swelling, with lids more than half closed -> 4
(VALUE A)

* Discharge
No discharge -> 0
Slight discharge -> 1
Discharge with humidification of lids and hair around -> 2
Discharge with humidification of lids and large area around -> 3
(VALUE B)

* Redness (refers to palpebral and bulbar conjunctivae; excluding cornea and iris)
Normal -> 0
Some blood vessels hyperaemic (injected) -> 1
Diffuse, crimson colour; individual vessels not easily discernible -> 2
Diffuse beefy red -> 3
(VALUE C)

- Iris
Normal -> 0
Markedly deepened rugae, congestion, swelling, moderate circumcorneal hyperaemia;
or injection; iris reactive to light (a sluggish reaction is considered to be an effect -> 1
Hemorrhage, gross destruction, or no reaction to light -> 2
(VALUE D)

- Cornea
* Opacity: degree of density (readings from most dense area)
No ulceration or opacity -> 0
Scattered or diffuse areas of opacity (other than slight dulling of normal lustre);
details of iris clearly visible -> 1
Easily discernible translucent area; details of iris slightly obscured -> 2
Nacrous area; no details of iris visible; size of pupil barely discernible -> 3
Opaque cornea; iris not discernible through the opacity -> 4
(VALUE E)

* Surface of opacity:
Less than 1/4 -> 1
Between 1/4 and 1/2 -> 2
Between 1/2 and 3/4 -> 3
Between 3/4 and whole surface -> 4
(VALUE F)

=> Conjunctiva score = 2 x (A + B + C)
=> Iris score = 5 x D
=> Cornea score = 5 x E x F
=> Individual total score (per time-point) = Conjunctiva + Iris + Cornea scores (maximum 110)
=> Maximum Mean Total Score (at a given time-point)

TOOLS USED TO ASSESS SCORE: Heine's ophthalmoscope ± slit lamp

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Remarks:

reading stopped at 48h

Remarks on result:

no indication of irritation

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

other: not applicable

Remarks:

reading stopped at 48h

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

3

Reversibility:

other: not applicable

Remarks:

reading stopped at 48h

Remarks on result:

no indication of irritation

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 24 hours

Remarks:

reading stopped at 48h

Remarks on result:

no indication of irritation

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

other: 1 hour

Score:

9.33

Max. score:

110

Reversibility:

fully reversible within: 3 days from instillation

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24 h

Score:

1.33

Max. score:

110

Reversibility:

fully reversible within: 3 days from instillation

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

48 h

Score:

0.67

Max. score:

110

Reversibility:

fully reversible within: 3 days from instillation

Irritant / corrosive response data:

See table below for details

Summary of the observed ocular irritation scores (3 rabbits)

 

Time after instillation	1 h			1 d			2 d
Rabbit number	448	449	450	448	449	450	448	449	450
Conjunctivae Chemosis Discharge Redness	2 1 1	1 1 1	1 1 0	1 0 0	0 0 0	1 0 0	0 0 0	0 0 0	0 0 0
Iris	1	1	0	0	0	0	0	0	0
Cornea Opacity Surface	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0
Individual score	13	11	4	2	0	2	2	0	0
Mean (3 animals)	-	-	9.33	-	-	1.33	-	-	0.67
Time after instillation	3 d			4d			7 d
Rabbit number	448	449	450	448	449	450	448	449	450
Conjunctivae Chemosis Discharge Redness	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0	0 0 0
Iris	0	0	0	0	0	0	0	0	0
Cornea Opacity Surface	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0	0 0
Individual score	0	0	0	0	0	0	0	0	0
Mean (3 animals)	-	-	0	-	-	0	-	-	0

Interpretation of results:

GHS criteria not met

Remarks:

slightly irritating

Conclusions:

Cerium Oxide is not classified as an eye irritant.

Executive summary:

In a primary eye irritation study (Institut Français de Toxicologie report No. 302314), 0.1 g of Cerium Oxide were instilled into the conjunctival sac of the right eye of 3 male New Zealand White rabbits. Exposed eyes were not washed. Animals then were observed for 7 days. Irritation was scored 1 hours after instillation and on days 1, 2, 3, 4 and 7 by calculating ocular irritation scores, based on the grading of conjunctiva, iris and cornea scores.

 

Slight to moderate conjunctival chemosis was observed in all 3 rabbits within 48 hours after instillation, together with slight conjunctival discharge in all animals and conjunctival enanthema and iris congestion in 2 animals, at 1 hour after instillation. All the irritation signs had reversed by day 3. Mean ocular irritation scores were 9.33, 1.33 and 0.67 at 1 h after instillation and on days 1 and 2, respectively.

 

The test substance was therefore not classified as irritant to the eye, according to the criteria of Annex VI Directive 67/548/EEC.

 

This study is classified as acceptable. It satisfies the OECD 405 guideline requirements for acute eye irritation or corrosion.

Reference 4

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: published data with limited level of details

Principles of method if other than guideline:

Standard Draize method

GLP compliance:

not specified

Specific details on test material used for the study:

No details provided

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

No details provided

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount applied: 0.1 g

Duration of treatment / exposure:

Single conjunctival instillation

Observation period (in vivo):

72 hours

Number of animals or in vitro replicates:

6

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing: rinsing with saline in 3 out of 6 eyes
- Time after start of exposure: 30 seconds post-instillation

SCORING SYSTEM:
According to the method of Draize (describe in: Draize HH et al. Methods for the study of irritation and toxicity of substances applied topically to the skin and mucous membranes. J. Pharmacol. Exp. Ther. 83: 377-90, 1944)

TOOL USED TO ASSESS SCORE: not specified

Irritation parameter:

other: Draize score

Basis:

mean

Remarks:

unwashed eyes

Time point:

other: 24 hours

Score:

8.3

Max. score:

110

Reversibility:

not fully reversible within: 72 hours post-instillation

Irritation parameter:

other: Draize score

Basis:

mean

Remarks:

unwashed eyes

Time point:

other: 48 hours

Score:

6.3

Max. score:

110

Reversibility:

not fully reversible within: 72 hours post-instillation

Irritation parameter:

other: Draize score

Basis:

mean

Remarks:

unwashed eyes

Time point:

other: 72 hours

Score:

1.3

Max. score:

110

Reversibility:

not fully reversible within: 72 hours post-instillation

Irritation parameter:

other: Draize score

Basis:

mean

Remarks:

washed eyes

Time point:

other: 24 hours

Score:

5.7

Max. score:

110

Reversibility:

fully reversible within: 72 hours post-instillation

Irritation parameter:

other: Draize score

Basis:

mean

Remarks:

washed eyes

Time point:

other: 48 hours

Score:

1.3

Max. score:

110

Reversibility:

fully reversible within: 72 hours post-instillation

Irritation parameter:

other: Draize score

Basis:

mean

Remarks:

washed eyes

Time point:

other: 72 hours

Score:

0

Max. score:

110

Reversibility:

fully reversible

Interpretation of results:

other: minimally irritating

Conclusions:

Cerium Oxide is considered to be minimally irritating to both washed and unwashed eyes when instilled undiluted but is not classified as an eye irritant according to the CLP criteria.

Reference 5

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2000-02-08 to 2000-03-23

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Well documented, scientifically sound study according to a method similar to OECD guideline 405 with a few deviations. However, not GLP, no information on environmental conditions, individual eye endpoints (cornea, iris, conjunctiva) not reported in the results.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

not GLP, no information on environmental conditions, individual eye endpoints (cornea, iris, conjunctiva) were not reported in the results

GLP compliance:

no

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Biotech Co., Ltd
- Age at study initiation: 4 months old
- Weight at study initiation: 3.22-3.59 kg
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data

IN-LIFE DATES: From: no data To: no data

Vehicle:

unchanged (no vehicle)

Controls:

other: right eyes were kept as controls

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1 g
- Concentration (if solution): not applicable

VEHICLE
- Amount(s) applied (volume or weight with unit): not applicable
- Concentration (if solution): not applicable
- Lot/batch no. (if required): not applicable
- Purity: not applicable

Duration of treatment / exposure:

single instillation

Observation period (in vivo):

1, 24, 48, and 72 hours

Number of animals or in vitro replicates:

3 animals (administered to the left eye of each animal)

Details on study design:

SCORING SYSTEM: According to Draize's standard (1959). Cornea, iris and conjunctiva were observed, and acknowledged damages were recorded. After calculating the total scores of each observation of each animal (Individual ocular irritation index, IOI) and the average score of each observation of each group (Mean ocular irritation index, MOI), the evaluation was made according to the AFNOR (1982) evaluation criteria. The acute ocular irritation index (AOI) was defined as the maximum of the MOI.

Accident Value Test of Corneal Epithelium: After the accident value test of anterior ocular segment done 24 hours after the application, corneal epithelium were dyed with fluorescein, and the stainability was evaluated.

TOOL USED TO ASSESS SCORE: hand-slit lamp

Irritation parameter:

other: MOI

Basis:

mean

Remarks:

of 3 animals

Time point:

other: 1 hour

Score:

4.7

Max. score:

110

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

other: MOI

Basis:

mean

Remarks:

of 3 animals

Time point:

24 h

Score:

6

Max. score:

110

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

other: MOI

Basis:

mean

Remarks:

of 3 animals

Time point:

48 h

Score:

2

Max. score:

110

Reversibility:

fully reversible within: 72 hours

Irritation parameter:

other: MOI

Basis:

mean

Remarks:

of 3 animals

Time point:

72 h

Score:

0

Max. score:

110

Reversibility:

other: not applicable

Irritation parameter:

other: AOI

Basis:

mean

Remarks:

of 3 animals

Time point:

24 h

Score:

6

Max. score:

110

Reversibility:

fully reversible within: 72 hours

Irritant / corrosive response data:

The AOI was determined to be 6.0 at 24 hours and the MOI after 48 hours was 2.0, therefore, this test agent was determined to be slightly irritating based on the AFNOR (1982) criteria. No irritation was observed after 72 hours.

The Accident Value Test of Corneal Epithelium 24 hours after application was zero in all three animals.

Other effects:

There were no abnormalities in the general condition or the weight changes to any of the 3 animals.

Interpretation of results:

GHS criteria not met

Conclusions:

The test agent was determined to be slightly irritating based on the AFNOR criteria. It does however not need to be classified for eye irritation according to the CLP criteria.

Reference 6

Endpoint:

eye irritation: in vivo

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Justification for type of information:

The in vivo eye irritation studies on cerium dioxide and yttrium zirconium dioxide (zirconium dioxide with a small w/w % of yttrium oxide in it) are considered relevant for supporting the conclusion drawn from the study conducted on the reaction mass of cerium dioxide and zirconium dioxide itself.
The read across justification document is attached to IUCLID Section 13.

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across source

Irritation parameter:

overall irritation score

Remarks:

read across conclusion

Remarks on result:

no indication of irritation

Remarks:

Based on the results of the in vivo studies performed with cerium dioxide and yttrium zirconium oxide, it can be concluded that no eye irritation requiring classification would be observed in a similar study with the reaction mass of cerium dioxide and zirconium dioxide. This was confirmed in the study performed with the reaction mass of cerium dioxide and zirconium dioxide itself.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin and eye irritation studies (Klimisch 1) are available for a representative nanoform of the reaction mass of cerium dioxide and zirconium dioxide. For skin irriation, a second study is available for the reaction mass but the nano-status of the test material is unclear. Further information on skin and eye irritation potential is also available for the constituents of the reaction mass, cerium dioxide and zirconium dioxide. As these constituents showed similar physicochemical, toxicological, ecotoxicological and environmental properties, results of studies performed on both constituents can be used as supporting studies. The studies on cerium dioxide and zirconium dioxide are mostly on bulk test materials. One of the studies conducted with cerium dioxide also investigated a nanoform of the substance.

Skin irritation

In a primary dermal irritation study (De Jouffrey, 1996b; Klimisch 1), 3 male New Zealand White rabbits were dermally exposed to 500 mg of the reaction mass of cerium dioxide and zirconium dioxide (representative nanoform) onto one flank. Test sites were covered with semi-occlusive dressing for 4 hours. The cutaneous examinations were performed 1, 24, 48 and 72 hours after removal of the dressing. The mean scores for erythema and oedema were calculated for 24, 48 and 72 hours.

No cutaneous reactions were observed during the study warranting classification.

In addition, an acute dermal irritation test in New Zealand White rabbits was performed by MEL Chemicals (2009) (Klimisch 1). Three rabbits were dermally exposed to 500 mg of the reaction mass of cerium dioxide and zirconium dioxide (nano-status unclear) onto a dorsal flank for 4 hours. Cotton gauze was used to apply the test substance to shorn skin. The cutaneous examinations were performed 1, 24, 48 and 72 hours after removal of the dressing. The mean scores for erythema and oedema were calculated for 24, 48 and 72 hours. No evidence of skin irritation was reported under the test conditions.

Both studies are used in a weight of evidence approach as they both indicate that the reaction mass is not irritating to skin.

The skin irritation properties of cerium dioxide were tested both in vitro and in vivo. In a in vivo study (Gonnet and Guillot, 1983; Klimisch 1), 3 male rabbits were dermally exposed to cerium dioxide for 4 hours and were observed up to 72 hours following application. No signs of cutaneous irritation were observed in this study. The absence of irritating properties was confirmed by another in vivo study (Lambert et al., 1993) and was consistent with in vitro testing (Park et al., 2007) where both bulk and nano cerium dioxide were considered unlikely to be a skin irritant based on results of an EpiDerm test.

A reliable (Klimisch 2) in vivo skin irritation study was performed with zirconium dioxide (BIBRA, 1986). The GLP study was performed according to OECD Guideline 404 with minor deviations. The substance was not irritating to New Zealand White rabbit skin after 4 hours of exposure. These observations were supported by the results of the non-GLP in vivo study of the Chemical Evaluation and Research Institute (2000a; Klimisch 2) conducted with zirconium dioxide containing a small w/w % yttrium oxide.

Taking all information together, it can be reasonably concluded that neither the nanoforms nor the bulk forms (should bulk forms be placed on the market) of the reaction mass are irritating to skin.

Eye irritation

In a primary eye irritation study (Klimisch 1), selected as the key study (De Jouffrey, 1996c), 100 mg of a representative nanoform of the reaction mass of cerium dioxide and zirconium dioxide was instilled into the conjunctival sac of the left eye of New Zealand White rabbits (3 animals). Eyes were not rinsed and the right eye served as a control. The ocular examinations were performed 1, 24, 48 and 72 hours after treatment. Mean scores calculated for each animal over 24, 48 and 72 hours were 1.0, 1.0 and 1.3 for chemosis, 0.3, 1.0 and 2.3 for redness of the conjunctivae, 0.0, 0.0 and 0.7 for iris lesions and 0.7, 0.3 and 1.3 for corneal opacity. Total reversibility was observed by day 4 (2 animals) or day 8.

Therefore, according to these results the reaction mass of cerium dioxide and zirconium dioxide is not classified as eye irritant based on the EU classification criteria. This conclusion was obtained for a representative nanoform but it can be safely concluded that a bulk form, should such form be placed on the market, would not cause irritation to an extent requiring classification either.

The conclusion is further supported by data available for bulk forms of cerium dioxide and for zirconium dioxide containing a small w/w % of yttrium oxide.

The eye irritation properties of cerium dioxide were tested in vivo. In one study (Klimisch 2) (Gonnet and Guillot, 1983), 3 male rabbits were observed for up to 7 days following a single conjunctival instillation of cerium dioxide in unwashed eyes. Signs of minimal ocular irritation were noted, mainly 1 hour after instillation, and had subsided by day 3. These changes were likely related to the mechanical irritation properties of cerium dioxide as a solid powder. These observations were consistent with the other study (Lambert et al., 1993) where cerium dioxide was found minimally irritating to both washed and unwashed rabbit eyes. However, due to their low intensity and short duration, the ocular changes did not warrant classification of cerium dioxide for eye irritation.

A reliable acute eye irritation and corrosion study was performed on yttrium zirconium dioxide (Chemical Evaluation and Research Institute, 2000b) in New Zealand White rabbits according to OECD guideline 405 with some minor deviations. The test substance was determined to be slightly irritating based on the AFNOR criteria. Observed effects were fully reversible within 72 hours. The substance however does not need to be classified for eye irritation according to the EU classification criteria.

	Reaction mass (nano)	Cerium dioxide (bulk)	Zirconium dioxide	Yttrium zirconium oxide
Skin irritation	Not irritating	Not irritating	/	Not irritating
Eye irritation	Not irritating	Not irritating	/	Not irritating

Justification for classification or non-classification

Based on the classification criteria of the CLP Regulation, the absence of dermal irritation and the low magnitude and rapid reversibility of ocular irritation in rabbits resulted in no classification for the reaction mass of cerium dioxide and zirconium dioxide for skin and eye irritation. These results are supported by those observed in the individual constituents.