Yttrium chloride hexahydrate

Endpoint summary

Description of key information

Skin irritation/corrosion

Yttrium trichloride hexahydrate was concluded not to be corrosive in an in vitro skin corrosion study performed according to OECD guideline 431 (Reconstructed Human Epidermis Test method, EPISKIN) and conform GLP requirements (Orovecz, 2016). In a consequent GLP-conform in vitro study performed according to OECD guideline 439 (EPISKIN), the substance was concluded not to be irritant to skin and does not require classification for skin irritation under the CLP Regulation (Varga-Kanizsai, 2017a). Both studies are reliable without restrictions (Klimisch 1) and are included in a weight of evidence approach for endpoint coverage.

Eye irritation

Yttrium trichloride hexahydrate was found to be a test item inducing serious eye damage (requiring classification as Eye Damage Cat. 1 under the CLP Regulation) in a bovine corneal opacity and permeability test (BCOP) performed according to OECD guideline 437 and conform GLP requirements (Gerbeix, 2017). This study was considered reliable without restrictions (Klimisch 1) and was assigned key status for endpoint coverage.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

11 August 2016 - 17 October 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Version / remarks:

28 July 2015

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EU Method B.40 Bis (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

31 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

No correction for purity of the test item was applied.

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: not specified (adult)

Source strain:

other: not applicable

Justification for test system used:

The EPISKIN (SM) model has been validated for corrosivity testing in an international trial (Fentem, 1998) and its use is recommended by the relevant OECD guideline for corrosivity testing (OECD No. 431). Therefore, it was considered to be suitable for this study.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN TM (SM) (0.38 cm²), SkinEthic, France
- Tissue batch number(s): 16-EKIN-032
- Expiry date: August 15, 2016
- Date of initiation of testing: August 11, 2016

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 24.2-25.3°C
- Temperature of post-treatment incubation (if applicable): 37.0°C
- All incubations were carried out in a humid atmosphere (80-100%) containing 5.0 ± 0.5% CO2 in air in the dark at 37.0 ± 1.0°C. Temperature and humidity were continuously monitored once on each working day. Temporary deviations from the temperature, humidity and CO2 percentage may occur due to opening and closing of the incubator door. Any variation to these conditions were evaluated and maintained in the raw data.

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: After the incubation time, the test item treated tissues or also the positive control tissues were removed and rinsed thoroughly with phosphate buffered saline (PBS) to remove all the remaining test or positive control material from the epidermal surface. Likewise, negative control tissues were processed accordingly. The rest of the PBS was removed from the epidermal surface using a pipette (without touching the epidermis).
- Observable damage in the tissue due to washing: no

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL
- Incubation time: 3 hours
- Spectrophotometer: yes, plate reader, not further specified
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 2

ADDITIONAL CONTROL TISSUES
- No additional control tissues were used for direct interference with MTT as there was no indication of direct interference during a preliminary experiment.
- As the test item had an intrinsic colour, two additional test item-treated living tissues were used for the non-specific OD evaluation. These tissues followed the same test item application and all steps as for the other tissues, except for the MTT step: MTT incubation was replaced by incubation with fresh Assay Medium to mimic the amount of colour from the test item that may be present in the test disks. OD readings were conducted following the same conditions as for the other tissues.

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
For 2 disks:
If both disks have mean viability of ≥ 35% = Non Corrosive
If both disks have mean viability of < 35% = Corrosive (at the corresponding incubation period)

Otherwise:
If the mean value is ≥ 35% and the variability is less than 50% = Non Corrosive
If the mean value is < 35% and the variability is less than 50% = Corrosive

VALIDITY OF THE TEST
- The mean OD value of the two negative control tissues should be ≥ 0.6 and ≤ 1.5 and negative control OD values should not be below historically established boundaries.
- The acceptable mean viability % range for positive control is ≤ 20%.
- The difference of viability between the two tissue replicates should not exceed 30%.
- The mean OD value of the blank samples (acidified isopropanol) should be < 0.1.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 20 mg (100 μL physiological saline was added to the test item to ensure good contact with the epidermis)

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL
- Concentration (if solution): 0.9% (w/v)
- Lot/batch no. (if required): 52532Y05-2
- Expiry date: 31 May 2018

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL
- Concentration (if solution): no data
- Lot/batch no. (if required): 15A160011
- Expiry date: 30 November 2017

Duration of treatment / exposure:

4 hours (± 10 min)

Number of replicates:

2 per group (test item, positive control, negative control)

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

mean of 2 replicates

Value:

86.7

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: range: 85.4 to 88.0%

Other effects / acceptance of results:

OTHER EFFECTS
- Visible damage on test system: no
- Direct-MTT reduction: no
- Colour interference with MTT: As the test item was coloured, two additional test item-treated living tissues were used for the non-specific OD evaluation. The mean optical density (measured at 570 nm) of these tissues was determined to be 0.003 and Non Specific Colour % (NSCliving%) was calculated as 0.4%. This is below the threshold of 5%, therefore correction due to colouring potential was not necessary.

VALIDITY OF THE TEST
After receipt, the two indicators of the delivered kits were checked. Based on the observed colours, the epidermis units were in proper conditions in each case.
The mean OD value of the two negative control tissues was in the recommended range (0.917).
The two positive control treated tissues showed 0.6% viability demonstrating the proper performance of the assay.
The difference of viability between the two test item-treated tissue samples in the MTT assay was 3.0%.
The mean OD value of the blank samples (acidified isopropanol) was 0.047.
All these parameters were within acceptable limits and therefore the study was considered to be valid.

RESULTS
Following exposure with yttrium trichloride hexahydrate, the mean cell viability was 86.7% compared to the negative control. This is above the threshold of 35%, therefore the test item was considered as being non-corrosive. The experiment met the validity criteria, therefore the study was considered to be valid.

Optical Density (OD) and the calculated Non Specific Colour % (NSCliving%) of the additional control tissues

Additional control		OD Measured	OD Blank Corrected	NSC% (living)
Treated with	1	0.054	0.007
Test Item	2	0.047	0.000	0.4
	Mean	-	0.003

Note: Mean blank value was 0.047. Optical density means the mean value of the duplicate wells for each sample (rounded to three decimal places).

Optical Density (OD) and the calculated relative viability % of the samples

Substance		OD Measured	OD Blank Corrected	Viability (%RV)
Negative Control	1	0.940	0.893	97.4
(0.9% (w/v) NaCl)	2	0.988	0.941	102.6
	mean	-	0.917	100.0
Positive Control	1	0.055	0.008	0.9
(Glacial Acetic Acid)	2	0.050	0.003	0.3
	mean	-	0.005	0.6
Test Item	1	0.854	0.807	88.0
	2	0.830	0.783	85.4
	mean	-	0.795	86.7

Note: Mean blank value was 0.047. Optical density means the mean value of the duplicate wells for each sample (rounded to three decimal places).

Interpretation of results:

GHS criteria not met

Conclusions:

Following exposure with the test item yttrium trichloride hexahydrate, the mean cell viability was 86.7% compared to the negative control. This is above the threshold of 35%, therefore the test item was considered as being non-corrosive. The experiment met the validity criteria, therefore the study was considered to be valid.
In conclusion, in the in vitro EPISKIN™(SM) model test, the results indicated that the test item is non-corrosive to skin.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

16 November 2016 - 17 January 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

28 July 2015

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

6 July 2012

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

No correction for purity of the test item was applied.

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: not specified (adult)

Source strain:

other: not applicable

Justification for test system used:

The EPISKIN TM (SM) model has been validated for irritation testing in an international validation study and its use is recommended by the relevant OECD guideline for irritation testing (OECD No. 439). Therefore, it was considered to be suitable for this study.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN TM (SM) (0.38 cm2), SkinEthic, France
- Tissue batch number(s): 16-EKIN-046
- Expiry date: 21 November 2016
- Date of initiation of testing: 16 November 2016

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 23.9-26.0°C
- Temperature of post-treatment incubation (if applicable): 37.0 ± 1.0°C
- All incubations were carried out in a humid atmosphere (> 95%) containing 5.0 ± 0.5% CO2 in air in the dark at 37.0 ± 1.0°C. Temperature and humidity were continuously monitored once on each working day. Temporary deviations from the temperature, humidity and CO2 percentage may occur due to opening and closing of the incubator door. Any variation to these conditions were evaluated and maintained in the raw data.

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: After 15 min incubation time, the EPISKIN TM (SM) units were removed and rinsed thoroughly with phosphate buffered saline (PBS) to remove any remaining material from the epidermal surface as much as possible. To remove the test item stuck on the surface of the epidermis additional rinsing was used. The rest of the PBS was removed from the epidermal surface with a pipette (without touching the epidermis).
- Observable damage in the tissue due to washing: no

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL
- Incubation time: 3 hours (± 5 min)
- Spectrophotometer: yes, plate reader, not further specified
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 3

ADDITIONAL CONTROL TISSUES
- As the test item was coloured, two additional test item-treated living tissues were used for the non-specific OD evaluation. These tissues followed the same test item application and all steps as for the other tissues, except for the MTT step: MTT incubation was replaced by incubation with fresh Assay Medium to mimic the amount of colour from the test item that may be present in the test disks. OD reading was conducted following the same conditions as for the other tissues.
- As no colour change (yellow colour) was observed after three hours of incubation of the test item in MTT working solution, the test material was concluded not to interact with MTT. Therefore, additional controls and data calculations were not necessary.

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA
- The test substance is considered to be non-irritant to skin if the relative mean viability of three individual tissues after 15 minutes exposure to the test item and 42 hours post incubation is more than 50% of the mean variability of the negative controls.

VALIDITY CRITERIA
- The mean OD value of the three negative control tissues should be between 0.6 and 1.5, and the standard deviation value (SD) of the % viability values should be ≤ 18.  
- The acceptable mean percentage viability range for positive controls is 0-40% and the standard deviation value (SD) of the % viability values should be ≤ 18.
- The SD calculated from individual % tissue viability values of the three test item treated replicates should be <18.
- The mean OD value of the blank samples (acidified isopropanol) should be <0.1.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 20 mg. As the test item was solid, first an appropriate amount (10 µL) of distilled water was applied to the epidermal surface in order to improve further contact between test item and epidermis.

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 μL
- Concentration (if solution): 5% (w/v)

Duration of treatment / exposure:

15 minutes (± 0.5 min)

Duration of post-treatment incubation (if applicable):

42 hours (± 1 h)

Number of replicates:

3 per group (test item, positive control, negative control)

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

mean of 3 replicates

Value:

91.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Remarks:

range: 80.5 to 98.7

Other effects / acceptance of results:

OTHER EFFECTS
- Visible damage on test system: no
- Direct-MTT reduction: no
- Colour interference with MTT: As the test item was coloured, two additional test item-treated tissues were used for the non-specific OD evaluation. The mean optical density (measured at 570 nm) of the two additional tissues was 0.009. Non Specific Colour % was calculated as 1.2%. This value was below 5%, therefore additional data calculation was not necessary.

VALIDITY OF THE TEST
After receipt, the two indicators of the delivered kit were checked. Based on the observed colours, the epidermis units were in proper conditions.
The mean OD value of the three negative control tissues was in the recommended range (0.744). Standard deviation of the viability results for negative control samples was 4.7.
The positive control treated tissues showed 6.3% viability demonstrating the proper performance of the assay. The standard deviation of the viability results for positive control samples was 1.6.
The standard deviation of viability values of the three test item-treated tissue samples in the MTT assay was 9.8.
The mean OD value of the blank samples (acidified isopropanol) was 0.046.
All these parameters met the acceptability criteria, therefore the study was considered to be valid.

INTERPRETATION OF RESULTS
Following exposure with yttrium trichloride hexahydrate, the mean cell viability was 91.8% compared to the negative control. This is above the threshold of 50%, therefore the test item was considered as being non-irritant to skin. The experiment met the validity criteria, therefore the study was considered to be valid.

Optical Density (OD) and the calculated Non Specific Colour % (NSCliving%) of the additional control tissue

Additional Control		OD Measured	OD Blank corrected	NSC%
Treated with	1	0.054	0.008
Test Item	2	0.055	0.009	1.2
	mean	-	0.009

Optical Density (OD) and the calculated relative viability % of the samples

Substance		OD Measured	OD Blank Corrected	Viability (% RV)
	1	0.790	0.744	100.1
Negative Control:	2	0.754	0.708	95.2
Phosphate Buffered Saline	3	0.824	0.778	104.7
	mean	---	0.744	100
Positive Control:	1	0.087	0.041	5.5
5% (w/v) SDS solution	2	0.085	0.039	5.3
	3	0.107	0.061	8.2
	mean	---	0.047	6.3
	1	0.645	0.599	80.5
Test Item	2	0.780	0.734	98.7
	3	0.761	0.715	96.2
	mean	---	0.683	91.8

Notes:

1. Mean blank value was 0.046.

2. Optical density means the mean value of the duplicate wells for each sample (rounded to three decimal places).

Interpretation of results:

GHS criteria not met

Conclusions:

Following exposure with the test item, the mean cell viability was 91.8% compared to the negative control. This is above the threshold of 50%, therefore the test item was considered as being non-irritant to skin. The experiment met the validity criteria, therefore the study was considered to be valid.
In conclusion, in the in vitro EPISKIN model test, the results indicated that the test item is non-irritant to skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01 December 2016 - 2 February 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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)

Version / remarks:

26 July 2013

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Treatment of test material prior to testing: The test item was tested neat (in its original form).
- Correction factor: No correction factor was applied for this type of study.

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Bovine eyes were obtained from freshly slaughtered cattle at the abattoir EVA, Saint-Pierre-sur-Dives, France.
- Characteristics of donor animals (e.g. age, sex, weight): bovine cattle were up to 12 months old (typically, 5 to 8 months old)
- Storage, temperature and transport conditions of ocular tissue (e.g. transport time, transport media and temperature, and other conditions): Eyes were transported at ambient temperature in a cool box, immerged in cooled buffered Hanks medium containing an antibiotic [Hank’s Balanced Salts Solution (HBSS) plus penicillin/streptomycin (100 units/100 μg/mL final)]. A container with smooth internal surfaces was used for transport to avoid damage to the corneas. The corneas were selected on the day of arrival in the laboratory.
- Time interval prior to initiating testing: Maximum 24 hours, stored individually in 12 mL of M199 medium containing 5% dextran, plus penicillin/streptomycin, at +4°C.
- Indication of any existing defects or lesions in ocular tissue samples: A careful macroscopic examination was performed on all eyes to detect the presence of any
defects (opacity, scratches, pigmentation, neovascularisation, etc). Any eyes with defects were discarded. The examination was performed under a lamp, using HBSS in order to keep the eyes moistened and shiny. Particular attention was paid to the corneas and the eyes were swiveled in order to observe the fringe areas and any scratches directly under the light.
- Indication of any antibiotics used: Hank’s Balanced Salts Solution (HBSS) plus penicillin/streptomycin (100 units/100 μg/mL final).

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 750 mg (± 75 mg)

NEGATIVE CONTROL
- Amount(s) applied (volume or weight with unit): 750 µL (± 8 µL)
- Concentration (if solution): 0.9% (w/v)

POSITIVE CONTROL
- Amount(s) applied (volume or weight with unit): 750 µL (± 8 µL)
- Concentration (if solution): 20% (w/v) in 0.9% NaCl (w/v)

Duration of treatment / exposure:

4 hours (± 5 minutes)

Duration of post- treatment incubation (in vitro):

90 minutes ± 5 minutes

Number of animals or in vitro replicates:

3 per group (test item, positive control, negative control)

Details on study design:

SELECTION AND PREPARATION OF CORNEAS
- Macroscopic examination was performed on all eyes to detect the presence of any defects (opacity, scratches, pigmentation, neovascularisation, etc). Any eyes with defects were discarded. The examination was performed under a lamp, using HBSS in order to keep the eyes moistened and shiny. Particular attention was paid to the corneas and the eyes were swiveled in order to observe the fringe areas and any scratches directly under the light.
- Tissues surrounding the eyeball were carefully pulled away and the cornea, surrounded by approximately 2 to 3 mm of sclera, was dissected out. The isolated corneas were stored in Hank’s Balanced Salts Solution (HBSS) until all corneas had been prepared.
- The corneas were washed 3 times for 15 min in HBSS plus penicillin/streptomycin (100 units/100 μg/mL final) at room temperature. The corneas were used within a maximum of 24 hours. Each cornea was stored individually in 12 mL of M199 medium containing 5% dextran, plus penicillin/streptomycin, at +4°C, for a maximum of 24 hours before use.
- The corneas were carefully examined macroscopically before their assembly in the holders, in order to detect the presence of any defects. Any corneas with defects were discarded. The corneas were then mounted in the corneal holders (one cornea per holder) with the endothelial side against the O-ring of the posterior chamber. The anterior half of the holder was then positioned on top of the cornea and tightened with screws.
- For pre-incubation, both chambers of the corneal holder were filled to overflowing with MEM culture media supplemented with 1% fetal bovine serum plus penicillin/streptomycin (cMEM) at room temperature. The posterior chamber was always filled first to maintain the natural concave shape of the cornea. After making sure that no air bubbles were present within the holder, it was immersed in a water bath, horizontally (cornea positioned vertically), up to approximately three quarters of its height. The holders were pre-incubated for 1 hour and 5 minutes (± 5 minutes) at +32°C (± 1°C).
- At the end of the pre-incubation period, the medium was removed from both chambers of the holder using a metal gavage tube attached to a vacuum pump to ensure complete evacuation. They were refilled with fresh cMEM (previously heated to +32°C), starting with the posterior chamber and taking care that no air bubbles were present. The chambers were re-sealed and the corneas were examined macroscopically through the holder to detect the presence of any defects. Then, the opacity of the cornea was measured to obtain OPT0.

QUALITY CHECK OF THE ISOLATED CORNEAS: Corneas that showed any macroscopic defect or an OPT0 value over 7 were discarded.

NUMBER OF REPLICATES: 3

TREATMENT METHOD
- Closed chamber method for negative and positive controls.
- Open chamber method for test item treatment.
- Application of test item: The window-locking ring and glass window from the anterior chamber were removed. The test item was gently applied onto the epithelium of the cornea, as uniformly as possible in order to ensure that it covers the whole epithelial surface. The glass window of the anterior chamber was then replaced (without the window-locking ring).

REMOVAL OF TEST SUBSTANCE
- Number of washing steps after exposure period: 4 times with pre-warmed cMEM containing phenol red, then the corneas were finally rinsed with pre-warmed cMEM without phenol red.

POST-EXPOSURE INCUBATION: Yes, 90 min in 5 mg/mL fluorescein stain at +32°C.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: An opacitometer was used to measure light transmission (i.e. the level of opacity) through the center of each mounted cornea. A numerical opacity measurement (arbitrary unit) was displayed and recorded.
- Corneal permeability: Passage of sodium fluorescein dye measured with the aid of UV/VIS spectrophotometry (OD490).

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)

ACCEPTANCE CRITERIA:
For the validation of an experiment, the following criteria had to be fulfilled:
- the mean In Vitro Irritancy Score (IVIS) of the positive control corneas should fall within two standard deviations of the historical mean;
- the mean opacity of the negative control corneas should be < 4.4;
- the mean OD490 nm of the negative control corneas should be < 0.043.

DECISION CRITERIA:
The IVIS cut-off values for identifying the test item as inducing serious eye damage (UN GHS Category 1) or as not requiring classification for eye irritation or serious eye damage (UN GHS No Category) are the following:
IVIS UN GHS
If the test item induces an IVIS ≤ 3 No category
If the test item induces an 3 < IVIS ≤ 55 No prediction can be made
If the test item induces an IVIS > 55 Category 1

A single experiment composed of at least three corneas is sufficient for a test item when the resulting classification is unequivocal.

Irritation parameter:

in vitro irritation score

Run / experiment:

mean of 3

Value:

93

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Remarks:

range: 88 to 97

Other effects / acceptance of results:

FURTHER DETAILS ON RESULTS
Mean opacity scores (range):
- negative control: 1.3 (0 to 3)
- positive control (corrected corneal opacity): 118.7 (107-127)
- test item (corrected corneal opacity): 87.7 (79-93)

Mean permeability scores (range):
- negative control: 0.036 (0.017-0.051)
- positive control (corrected optical density): 2.912 (2.456-3.272)
- test item (corrected optical density): 0.386 (0.224-0.648)

Mean in vitro irritancy score (range):
- positive control: 162 (156-168)
- test item: 93 (88-97)

No notable opaque spots or irregularities were observed on negative control corneas.
Opacity, fluorescein fixation and thickening of the corneas were observed on those treated with the test item and with the positive control.

All acceptance criteria were fulfilled. The study was therefore considered as valid.

The mean In Vitro Irritancy Score (IVIS) of the test item-treated corneas was 93.

As the mean IVIS was > 55, the test item was considered as inducing serious eye damage (UN GHS Category 1).

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Conclusions:

Under the experimental conditions of this study, the test item was identified as a test item inducing serious eye damage (UN GHS Category 1).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irreversible damage)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation/corrosion

First, a comparable to guideline study (Krivograd, 2016; Klimisch 2) was performed in which the pH of a 10% solution of yttrium trichloride hexahydrate was determined to be 4.499, 5.553 and 4.488 (three measurements) (see IUCLID Section 4.20). Therefore, a determination of the acid reserve was not considered applicable and based on these data the substance was not considered to be corrosive. Consequently, an in vitro skin corrosion test was initiated.

Orovecz (2016; Klimisch 1) performed an in vitro skin corrosion study using the EPISKIN TM (SM) human epidermis model according to OECD guideline 431 and conform GLP requirements. Following exposure with the test item yttrium trichloride hexahydrate, the mean cell viability was 86.7% compared to the negative control. This is above the threshold of 35%, therefore the test item was considered as being non-corrosive. The experiment met the validity criteria, therefore the study was considered to be valid.

Consequently, Varga-Kanizsai (2017a; Klimisch 1) performed an in vitro skin irritation study using the EPISKIN TM (SM) human epidermis model according to OECD guideline 439 and conform GLP requirements. Following exposure with the test item, the mean cell viability was 91.8% compared to the negative control. This is above the threshold of 50%, therefore the test item was considered as being non-irritant to skin. The experiment met the validity criteria, therefore the study was considered to be valid.

Based on the results of the two in vitro studies (which were included in a weight of evidence approach), it was concluded that yttrium trichloride hexahydrate is non-irritant to skin and does not need to be classified for this endpoint under the CLP Regulation.

Eye irritation

A single in vitro study is available for this endpoint. In this study, Gerbeix (2017) performed a bovine corneal opacity and permeability test according to OECD guideline 437 and conform GLP requirements. The irritating potential of the test item yttrium trichloride hexahydrate was based on the calculation of an IVIS (In Vitro Irritancy Score) which combines permeability and opacity values for each cornea. The mean IVIS for the three replicates exposed to the test item was 93. Since the IVIS was > 55, it was concluded that the test item is capable of inducing serious eye damage and needs to be classified for Eye Damage Cat. 1 under the CLP Regulation. This study is considered reliable without restrictions and is assigned key status for endpoint coverage.

Justification for classification or non-classification

Skin irritation/corrosion

The test item was demonstrated not to be irritant to skin in an in vitro study performed according to OECD guideline 439 and is therefore not to be classified according to the CLP regulation.

Eye irritation

The test item was demonstrated to be capable of inducing serious eye damage in an ex vivo study performed according to OECD guideline 437 and is therefore classified as Eye Damage Cat. 1 according to the CLP Regulation.