Cesium fluoroaluminate

Endpoint summary

Description of key information

Skin irritation: not irritating (OECD 439, GLP)

Eye irritation: not irritating (OECD 437, GLP)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-08-17 to 2017-11-03

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:

2015-07-28

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2015-09-14

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature

Test system:

human skin model

Source species:

human

Cell type:

other: normal, human-derived epidermal keratinocytes

Cell source:

other: humans

Source strain:

not specified

Details on animal used as source of test system:

not applicable

Justification for test system used:

In an international prevalidation study performed by ECVAM, the in vitro skin irritation test using the human skin model EpiDerm™ and measurement of cell viability by dehydrogenase conversion of MTT into a blue formazan salt have turned out as a sufficiently promising predictor for skin irritancy potential.

Vehicle:

other: Dulbecco's phosphate buffered saline

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ skin model (source: MatTek Corporation, 82105 Bratislava, Slovakia)
- Tissue lot number: 25853
- Delivery date: 2017-11-01

TEMPERATURE USED FOR TEST SYSTEM
- Temperature of pre-incubation: 37 ± 1.5 °C (about 90 minutess)
- Temperature used during treatment / exposure: 37 ± 1.5 °C for 35 minutes, room temperature for 25 minutes
- Temperature of post-treatment incubation: 37 ± 1.5 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
After the end of the treatment interval the inserts were rinsed with DPBS at least 15 times in order to remove any residual test material.

After the rinsing the inserts were submerged in DPBS at least three times. Afterwards the inserts were again rinsed with DPBS. The tissues were then transferred into plates with assay medium. Tissues were incubated for about 23.5 hours at 37 ± 1.5 °C, 5 ± 0.5 % CO2. After incubation medium will be changed (pre-warmed fresh medium). Thereafter tissues were incubated for another approximately 18 hours at 37 ± 1.5 °C, 5 ± 0.5 % CO2. The complete incubation time was 41.5 hours.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL (300 µL/ well)
- Incubation time with MTT: 3 hours
- Extraction of Formazan: after the incubation period, the tissues were rinsed three times with DPBS. The tissues were transferred into new plates containing extractant solution (isopropanol) in each well ensuring that the tissues were completely covered and the plate was sealed to inhibit the isopropanol evaporation. The formazan salt was extracted for about 2.5 hours while shaking at room temperature.
After the extraction period was completed, the inserts were pierced with an injection needle to allow the extract to run into the well from which the insert was taken and the insert was discarded. The 24-well plates were placed on a shaker for 15 minutes until the solution was homogeneous in colour.
Per each tissue, 3 × 200 μL aliquots of the blue formazan solution were transferred into a 96-well flat bottom microtiter plate from the 15 minutes exposure. The optical density was determined with a microplate reader. Mean values were calculated from the 3 wells per tissue.
- Spectrophotometer: Versamax® Molecular Devices
- Wavelength: 570 nm

TEST FOR COLOUR INTERFERENCE
Before the test started, functional check for colour interference was performed. 25 ± 2 mg of the test item were added to deionised water. The mixture was incubated in the incubator (37 ± 1.5 °C, 5 ± 0.5 % CO2) for 60 minutes. At the end of the exposure time, the mixture was shaken and the presence and intensity of the staining (if any) was evaluated.

TEST FOR DIRECT MTT REDUCTION
The test item was evaluated for its potential to interfere with MTT assay. To test if a test item directly reduces MTT, 25 ± 2 mg of the test item were added to 1 mL of the MTT-solution (1mg/mL) and was incubated in the incubator (37 ± 1.5 °C, 5 ± 0.5% CO2) for 60 minutes. Untreated MTT medium was used as control.

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: tissues pass analysis for tissue viability
- Barrier function: tissues pass analysis for tissue functionality
- Morphology: presence of a functional stratum corneum, a viable basal cell layer, and intermediate spinous and granular layers
- Contamination: absence of bacteria, yeast, and other fungi (long term antibiotic, antimycotic free culture) as well as absence of HIV1- virus, Hepatitis B virus, and Hepatitis C virus
Please also refer to the field "Attached background material" below.

PREDICTION MODEL / DECISION CRITERIA
The mean optical density (OD) of the three negative control tissues was calculated after blank correction. This value corresponds to 100% tissue viability in the current test. For each individual tissue treated with the test item or the positive control the individual relative tissue viability is calculated according to the following formula: relative viability(%) = (mean OD test item or positive control/ mean OD of negative control) x 100
For the test item and the positive control, the mean relative viability ± relative standard deviation of the three individual tissues was calculated and used for classification according to the following prediction model: if the mean relative tissue viability of three individual tissues is less or equal to 50% of the negative control, the test item needs to be classified and labeled for its skin irritauion potential: Category 2 – irritant, H315 according to Regulation (EC) No 1272/2008.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): approx. 25 mg of the test item, wetted with vehicle

VEHICLE
- Amount(s) applied (volume or weight with unit): 25 µL DPBS
- Lot no.: 23308

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL DPBS

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL of a 5% Sodium Lauryl Sulfate (SLS) solution

Duration of treatment / exposure:

60 minutes

Duration of post-treatment incubation (if applicable):

41.5 hours

Number of replicates:

triplicates

Irritation / corrosion parameter:

% tissue viability

Remarks:

(mean)

Value:

59.7

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Colour interference with MTT: the test item did not change colour in the presence of water. An additional test with viable tissues (but without MTT addition) was not necessary to be performed.
- Direct-MTT reduction: the MTT solution did not turn blue/purple, the test item was not considered to reduce MTT and an additional test with freeze-killed tissues did not have to be performed.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: after treatment with the negative control, the absorbance values (1.406, 1.436, and 1.451 (mean: 1.431)) were well within the required acceptability criterion of mean OD ≥ 0.8 and ≤ 2.8 for the 60 minutes treatment interval.
- Acceptance criteria met for positive control: treatment with the positive control induced a decrease in the relative absorbance compared with the negative control to 4.7 % (acceptability criterion: positive control is ≤ 20 %).
- Acceptance criteria met for variability between replicate measurements: the relative standard deviations between the % variability values of the test item, the positive and negative controls in the main test were below 6 % (threshold of the "OECD Guideline for the Testing of Chemicals 439: In vitro Skin Irritation: Reconstructed Human Epidermis Test Method”: < 18%).
Please refer to the field "Any other information on results incl. tables" below

HISTORICAL DATA

Positive Control		Negative Control [OD570]
Mean Viability	4.37%	Mean Absorption	1.74
Rel. Standard Deviation	21.60%	Rel. Standard Deviation	9.40%
Range of Viabilities	2.20% - 6.78%	Range of Absorbance	1.34– 2.00
Mean Absorption	0.08
Rel. Standard Deviation	20.12%
Range of Absorbance	0.03 - 0.11

Data of 103 studies performed from July 2015 until March 2017

Table 1: Results after treatment with cesium tetrafluoroaluminate and the controls

Treatment group	Tissue No.	OD 570 nm Well 1	OD 570 nm Well 2	OD 570 nm Well 3	Mean OD of 3 Wells	Mean-OD of 3 wells blank corrected	Mean OD of 3 tissues blank correction	Mean Rel. Viablity [%]*
Blank		0.037	0.037	0.037	0.037
Negative Control	1	1.447	1.438	1.444	1.443	1.406	1.431	100.0
	2	1.468	1.481	1.469	1.473	1.436
	3	1.452	1.499	1.514	1.488	1.451
Positive Control	1	0.104	0.103	0.103	0.104	0.067	0.067	4.7
	2	0.105	0.104	0.104	0.104	0.067
	3	0.104	0.106	0.105	0.105	0.068
Test Item	1	0.902	0.909	0.927	0.913	0.876	0.854	59.7
	2	0.826	0.835	0.840	0.834	0.797
	3	0.929	0.925	0.930	0.928	0.891

*mean relative viabiliy [rounded values]:100 x (mean absorbance (test item/ positive control/negative control))/ (mean absorbance (negative control))

Interpretation of results:

GHS criteria not met

Conclusions:

The test item is not irritating to the skin.
According to the Regulation (EC) No 1272/2008 and subsequent regulations, the test item is not irritating to the 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:

2017-08-29

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:

2013-07-26

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2015-09-14

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: AB Schlachthof GmbH & Co. KG, 63739 Aschaffenburg, Germany
- Characteristics of donor animals: at least 9 month old donor cattle
- Storage, temperature and transport conditions of ocular tissue: isolated eyes were transported to the laboratory in Hank’s Buffered Salt Solution (HBSS) supplemented with streptomycin / penicillin.
- Time interval prior to initiating testing: corneae were isolated and used on the same day after delivery of the eyes

Vehicle:

other: 0.9 % NaCl in deionised water

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.75 mL
- Concentration: 20 % suspension (w/v) in vehicle

Duration of treatment / exposure:

240 minutes

Observation period (in vivo):

not applicable

Duration of post- treatment incubation (in vitro):

not required

Number of animals or in vitro replicates:

Number of bovine corneae per dose:
Test item: triplicates
Negative control: triplicates
Positive control: triplicates

Details on study design:

PREPARATION OF CORNEAS
- each isolated cornea was mounted in a specially designed cornea holder according to the description given in OEDC guideline 437, which consists of anterior and posterior compartments, which interface with the epithelial and endothelial sides of the cornea, respectively. Both compartments of the holder were filled with incubation medium cMEM (MEM, supplemented with sodium bicarbonate, L-glutamine, penicillin/streptomycin and 1 % fetal calf serum).
- for equilibration, the corneae in the holder were incubated in a vertical position for about one hour at 32 ± 1 °C in a water-bath.

QUALITY CHECK OF THE ISOLATED CORNEAS
- all eyes were carefully examined macroscopically for defects before removing the cornea. Those presenting defects such as vascularization, pigmentation, opacity and scratches were discarded.
- at the end of the equilibration period of the corneae in the holder, the basal opacity was determined (t0).
- each corneae with a value of the basal opacity > 7 was discarded.

APPLICATION DOSE AND EXPOSURE TIME
- the anterior compartment received the test item suspension or negative or positive control at a volume of 0.75 mL each on the surface of the corneae.
- corneae were incubated in a horizontal position at 32 ± 1 °C in the water-bath (incubation time: 240 minutes).
- after the incubation time, the test item or control items were rinsed off with saline.
- fresh incubation medium was added into the anterior compartment and opacity was measured (t240).
- permeability of the corneae was determined.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity: the opacitometer (OP_KiT opacitometer (Electro Design)) was calibrated and the opacity of each of the corneae was determined by reading each holder placed in the photoreceptor compartment for treated cornea.
Evaluation of opacity:
- the change of opacity value of each treated cornea or positive and negative control corneae is calculated by subtracting the initial basal opacity from the post treatment opacity reading (t240 – t0), for each individual cornea.
- the average change in opacity of the negative control corneae is calculated and this value is subtracted from the change in opacity of each treated cornea or positive control to obtain a corrected opacity.

- Corneal permeability: passage of sodium fluorescein dye measured with the aid of microplate reader (Versamax® Molecular Devices)(OD490).
- after the final opacity measurement was performed, the incubation medium was removed from the anterior compartment and replaced by 0.5% (w/v) sodium fluorescein solution in HBSS
- corneae were incubated in a horizontal position for 90 ± 10 minutes in a water-bath at 32 ± 1 °C.
- incubation medium from the posterior compartment was removed, mixed and the optical density at 490 nm was determined with a microplate reader.
Evaluation permeability:
- the corrected OD490 value of each cornea treated with positive control or test item is calculated by subtracting the average negative control cornea value from the original permeability value for each cornea.

SCORING SYSTEM: In Vitro Irritancy Score (IVIS)
The following formula is used to determine the IVIS of the negative control:
IVIS = opacity value + (15 x OD490 value)
The following formula is used to determine the IVIS of the positive control and the test item:
IVIS = (opacity value – corrected opacity value mean negative control) + (15 x corrected OD490 value)
The mean IVIS value of each treated group is calculated from the IVIS values.
Depending on the IVIS score obtained, the test item is classified into the following category according to OECD guideline 437 (please refer to table 1 in the field "Any other information on material and methods incl. tables" below).

DECISION CRITERIA:
The test will be acceptable if:
- the positive control gives an IVIS that falls within two standard deviations of the current historical mean (updated every three months), and if
- the negative control responses result in opacity and permeability values that are less than the established upper limits for background opacity and permeability values for bovine corneae treated with the respective negative control.

Irritation parameter:

in vitro irritation score

Value:

0.24

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- for the negative control an increase of neither opacity nor permeability of the corneae could be observed (mean IVIS = 1.38).
- the positive control showed clear opacity and distinctive permeability of the corneae (mean IVIS = 127.81) corresponding to a classification as serious eye damaging (CLP/EPA/GHS (Cat 1)).

Please refer to the field "Any other information on results incl. tables" below.

Table 1: Results after 240 Minutes Treatment Time

Test Group	Opacity value = Difference (t240-t0) of Opacity		Permeability at 490 nm (OD490)		IVIS	Mean IVIS	Proposedin vitroIrritancy Score
		Mean		Mean
Negative Control	0	0.33	0.065	0.070	0.98	1.38	Not categorized
	0		0.068		1.02
	1		0.077		2.16
Positive Control	133.67*		0.006*		133.76	127.81	Category 1
	122.67*		0.011*		122.83
	126.67*		0.011*		126.83
Cesium tetrafluoroaluminate	0.67*		0.002*		0.70	0.24	Not categorized
	-0.33*		-0.011*		-0.50
	0.67*		-0.010*		0.52

*corrected values

** negative values will be set to zero

Table 2: Historical Data

	Positive Control	Negative Control
Mean IVIS	115.29	1.28
Standard Deviation IVIS	9.57	0.20
Range of IVIS	98 - 131	1 - 2
Mean Opacity t240min	113.93	0.20
Standard Deviation Opacity t240min	12.24	0.20
Range of Opacity t240min	82 - 135	000 - 000
Mean Permeability	0.09	0.07
Standard Deviation of Permeability	0.12	0.01
Range of Permeability	000 - 001	000 - 000

Values of 41 studies with solid test items sharing 20 sets of controls, performed between January 2017 and October 2017.

Interpretation of results:

GHS criteria not met

Conclusions:

Relative to the negative control, the test item Cesium tetrafluoroaluminate did not cause an increase of the corneal opacity. The calculated mean in vitro irritancy score was 0.24. According to OECD 437 and in accordance with Regulation (EC) 1272/2008 and subsequent regulations the test item is not categorized (GHS).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation

The substance was not observed to be irritating to the skin in a reliable in vitro skin irritation study according to OECD 439.

Eye irritation:

The substance was not oberved to be irritating to the eye in a reliable in vitro eye irritation study according to OECD 437.

Justification for classification or non-classification

Skin irritation

The substance does not possess an skin irritating potential based on an in vitro OECD 439 (2015) test and does not require classification as skin irritating according to Regulation (EC) No 1272/2008 and its subsequent adaptations.

Eye irritation:

The substance does not possess an eye irritation potential according to an in vitro OECD 437 test and does not require classification as eye irritant according to Regulation (EC) No 1272/2008 and its subsequent adaptations.