Reaction product of 4-aminophenol with 2-ethyl-6-methylbenzenamine and sodium polysulfide

Endpoint summary

Description of key information

Skin irritation:

Based on the results of an OECD 439 study, the test item is considered not to be irritant to skin (UN GHS no Category).

Eye irritation:

Based on the results of an OECD 438 study, the test item is considered not to have an eye damaging potential (not UN GHS Cat. 1).

Based on the results of an OECD 437 study, the test item is considered not to have an eye damaging potential (UN GHS no Category).

These two in vitro studies lead to the overall conclusion that the test item has no eye damaging potential (UN GHS no Category).

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:

12 December 2016 - 01 March 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:

2015 July 28

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2012 July 06

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Vehicle:

unchanged (no vehicle)

Control samples:

yes, concurrent negative control

yes, concurrent positive control

yes, concurrent MTT non-specific colour control

Amount/concentration applied:

The epidermal surface was first moistened with 5 µL deionised water in order to improve further contact between powder and epidermis. Subsequently, 10 mg of the test item was applied evenly to the epidermal surface.

Duration of treatment / exposure:

The plates with the treated epidermis units were incubated for the exposure time of 15 minutes (± 0.5 min) at room temperature.
After the incubation time the EpiSkinTMSM units were removed and rinsed thoroughly with approximately 25 mL PBS 1x solution to remove all of the test material from the epidermal surface. The rest of the PBS was removed from the epidermal surface with suitable pipette tip linked to a vacuum source (care was taken to avoid the damage of epidermis).

Duration of post-treatment incubation (if applicable):

After rinsing the units were placed into the plate wells with fresh pre-warmed maintenance medium (2 mL/well) below them and then incubated for 42 hours (± 1 h) at 37 °C in an incubator with 5 % CO2, ≥ 95 % humidified atmosphere.

Number of replicates:

In this assay 3 replicates per test item and 3 replicates negative controls, 3 replicates positive controls, 2 replicates colour controls and 2 replicates non-specific colour control were used. Furthermore, 3 killed treated tissues and 3 killed negative control tissues are used for the MTT evaluation.

Irritation / corrosion parameter:

% tissue viability

Remarks:

mean

Run / experiment:

1-3

Value:

96

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

Validity of the Test
The mean OD value of the three negative control tissues was 1.048. The mean OD value obtained for the positive control was 0.116 and this result corresponds to 11 % viability when compared to the results obtained from the negative control. Each calculated standard deviation value (SD) for the % viability was below 18. All validity criteria were within acceptable limits and therefore the study can be considered as valid.

Indicator for potential false viability
Possible direct MTT reduction with test item:
As the test item has an intrinsic colour (black to brownish black), the check-method for possible direct MTT reduction with test item was impossible. The direct interaction with MTT was not defined. However, to avoid the effect of possible interactions with the MTT, an additional control was necessary.
The non-specific MTT reduction (NSMTT) was determined to be 0.488 %. As the NSMTT were below 50 % the true MTT metabolic conversion in all occasions and the correction of viability percentages were undertaken.

Colouring potential of test item:
As the test item has an intrinsic colour (black to brownish black), two additional test item-treated tissues were used for the non-specific OD evaluation. Mean OD (measured at 570 nm) of these tissues was determined as 0.010. The Non Specific Colour % (NSC %) was calculated as 0.9 % (below 5 %). Therefore additional data calculation was not necessary. A false estimation of viability can be precluded.

Table 1: OD values and viability percentages of the controls:

Substance	Optical Density (OD)		Viability (%)
Negative Control: 1x PBS	1	1.135917	108
	2	0.909867	87
	3	1.096867	105
	mean	1.047550	100
	standard deviation (SD)		11.53
Positive Control: SDS (5 % aq.)	1	0.053267	5
	2	0.090567	9
	3	0.203817	19
	mean	0.115883	11
	standard deviation (SD)		7.48

Table 2: OD values and viability percentages of the test item (including corrected values):

Test Item	Optical Density (OD)		TODTT	Viability (%)	Relative Viability (%)
	1	0.980617	0.975500	94	93
	2	1.090367	1.085250	104	104
	3	0.957067	0.951950	91	91
	mean	1.009350	1.004233	96	96
	standard deviation (SD)			6.79	6.79

Table 3: OD values of additional controls for MTT-interacting test item:

Additional controls	Optical Density (OD)
Negative control killed tissues: 1x PBS	1	0.022267
	2	0.026317
	3	0.030267
	mean	0.026283
Test item treated killed tissues:	1	0.025767
	2	0.032567
	3	0.035867
	mean	0.031400

Table 4: OD values and NSC % of additional control:

Additional colour control	Optical Density (OD)		Non Specific Colour %(NSC %)
Test item (test item treated tissueswithout MTT incubation)	1	0.009117	0.9
	2	0.010217
	mean	0.009667

Interpretation of results:

GHS criteria not met

Conclusions:

The test item is determined not to be irritant to skin and is therefore not classified (UN GHS No Category).

Executive summary:

EpiSkinTMSM test with the test item has been performed to predict its irritation potential by measurement of its cytotoxic effect, as reflected in the MTT assay, according to the OECD Test Guideline No. 439. Disks of EPISKIN (three units) were treated with test item and incubated for 15 minutes at room temperature. Exposure of test material was terminated by rinsing with PBS 1x solution. Epidermis units were then incubated at 37 °C for 42 hours in an incubator with 5% CO2. The viability of each disk was assessed by incubating the tissues for 3 hours with MTT solution at 3 7°C in 5% CO2 protected from light. The precipitated formazan was then extracted using acidified isopropanol and quantified spectrophotometrically. SDS (5% aq.) and 1×PBS treated (three units / positive and negative control) epidermis were used as positive and negative controls respectively. For each treated tissue viability was expressed as a percentage relative to negative control. The test item has an intrinsic colour (black to brownish black), therefore two additional test item treated tissues were used for the non-specific OD evaluation. The test item is also a possible MTT-reducer, therefore additional controls (test item treated killed tissues and negative control treated killed tissues) were used to detect and correct for test substance interference with the viability measurement. As the test item is a possible MTT-reducer and has an intrinsic colour (black to brownish black) to avoid a possible double correction for colour interference, a third control for non-specific colour in killed tissues was performed. Two killed treated tissues were used to avoid a possible double correction for colour interference. The test chemical is identified as requiring classification and labelling according to UN GHS (Category 2 or Category 1), if the mean relative viability after 15 minutes exposure and 42 hours post incubation is less or equal (≤) to 50% of the negative control.

In this in vitro skin irritation test using the EPISKIN model, the test item did not show significantly reduced cell viability in comparison to the negative control (mean viability: 96 %). All obtained test item viability results were above 50 % when compared to the viability values obtained from the negative control. Positive and negative controls showed the expected cell viability values within acceptable limits. The experiment was considered to be valid. The results obtained from this in vitro skin irritation test, indicated that the test item reveals no skin irritation potential under the utilised testing conditions. The test item is considered to be non-irritant to skin and is therefore not classified (UN GHS No Category).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Reference 1

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

26 July 2017 - 05 March 2018

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 Ocular Corrosives and Severe Irritants)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

- Source: Schlachthof Aschaffenburg, 63739 Aschaffenburg, Germany
- Age at study initiation: at least 9 month old donor cattle

Vehicle:

physiological saline

Controls:

yes, concurrent vehicle

yes, concurrent positive control

Amount / concentration applied:

The test item was tested as a 20% suspension (w/v) in saline using sonication for 10 minutes. Prior to treatment of the corneae the pH-value of the test item suspension was determined (pH 7.79).

Duration of treatment / exposure:

240 minutes

Number of animals or in vitro replicates:

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

Details on study design:

Three corneas were exposed to each 0.75 mL of a 20% (w/v) suspension of the stest item in physiological saline for 240 minutes.
After treatment the test item suspension was rinsed off the corneas and the corneas' opacity was determined. In a second step the permeability of the corneas was determined photometrically after 90 minutes treatment with fluorescein solution.

SCORING SYSTEM:
Opacity measurement
The opacitometer determines changes in the light transmission passing through the corneae, and displays a numerical opacity value. This value was recorded in a table. The opacitometer OP_KiT opacitometer (Electro Design, 63-Riom France) was calibrated as described in the manual and the opacity of each of the corneae was determined by reading each holder placed in the photoreceptor compartment for treated cornea.

For equilibration and prior to application of the test item or controls, the corneae in the holder were incubated in a vertical position for about one hour at 32 ± 1 °C in a water-bath. At the end of the incubation period, the basal opacity was determined (t0). After exposure of the corneae to the test groups, after rinsing and further incubation of the corneae for two hours, the opacity value was determined again (t240).

Permeability Determination
Following to the opacity readings, the permeability was measured as an indication of the integrity of the epithelial cell sheets. After the final opacity measurement was performed, the incubation medium will be removed from the anterior compartment and replaced by 1 mL of a 0.5% (w/v) sodium fluorescein solution in HBSS. Corneae were incubated again in a horizontal position for 90 ± 10 minutes in a water-bath at 32 ± 1 °C. Incubation medium from the posterior compartment were removed, well mixed and transferred into a 96 well plate and the optical density at 490 nm (OD490) was determined with a spectrophotometer (Versamax® Molecular Devices). The absorbance values will be determined using the software SoftMax Pro Enterprise (version 4.7.1).

DATA EVALUATION
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.

Permeability
The corrected OD490 value of each cornea treated with positive control and test item is calculated by subtracting the average negative control cornea value from the original permeability value for each cornea.

IVIS Calculation
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 – 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 score obtained, the test item is classified into the following category according to OECD guideline 437:

IVIS: In vitro Irritancy Score (according to OECD 437):

≤ 3 No Category (according to GHS)
> 3; ≤ 55 No prediction can be made
> 55 Serious eye damaging according to CLP/EPA/GHS (Cat 1)


Criteria for Determination of a Valid Test

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

Remarks:

mean

Run / experiment:

1-3

Value:

2.18

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Irritation parameter:

in vitro irritation score

Remarks:

Replicate 1

Run / experiment:

1

Value:

2.09

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Irritation parameter:

in vitro irritation score

Remarks:

Replicate 2

Run / experiment:

1

Value:

2.2

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Irritation parameter:

in vitro irritation score

Remarks:

Replicate 3

Run / experiment:

1

Value:

2.26

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Results after 240 Minutes Treatment Time

Test Group	Opacity value = Difference (t240-t0) of Opacity		Permeability at 490 nm (OD490)		IVIS	Mean IVIS	Proposed in vitro Irritancy Score	Standard deviation of in vitro score
		Mean		Mean
Negative Control	0	0.00	0.054	0.057	0.81	0.86	Not categorized	0.04
	0		0.059		0.89
	0		0.058		0.87
Positive Control	121.00*		0.019*		121.29	119.53	Category 1	2.91
	116.00*		0.011*		116.17
	121.00*		0.009*		121.14
Test item	2.00*		0.006*		2.09	2.18	Not categorized	0.08
	2.00*		0.013*		2.20
	2.00*		0.017*		2.26

*corrected values

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, according to the current study and under the experimental conditions reported, the test item is not categorised as an eye irritant (GHS).

Executive summary:

This in vitro study according to OECD guideline 437 was performed to assess the corneal damage potential of the test item by means of the BCOP assay using fresh bovine corneas. After a first opacity measurement of the fresh bovine corneas (t0), the 20% (w/v) suspension in saline of the test item, the positive, and the negative controls were applied to the different corneas and incubated for 240 minutes at 32 ± 1 °C. After the incubation phase, the test item as well as the positive and the negative controls were each rinsed from the corneas and opacity was measured again (t240). After the opacity measurements, permeability of the corneas was determined by measuring spectrophotometrically the transfer of sodium fluorescein after incubation in a horizontal position for 90 minutes at 32 ± 1 °C.

For the negative control (saline) neither an increase of opacity nor permeability of the corneas could be observed (mean IVIS =0.86). The positive control (10% (w/v) benzalkonium chloride in saline) showed clear opacity and distinctive permeability of the corneas (mean IVIS = 119.53) corresponding to a classification as serious eye damaging (CLP/EPA/GHS (Cat 1)). The negative control responses resulted in opacity and permeability values that are less than the established upper limits for background opacity and permeability values for bovine corneas treated with the respective negative control. Therefore the acceptability criteria were fulfilled. The test item was tested as suspension. Relative to the negative control, the test item did not cause a relevant increase of the corneal opacity. The calculated mean IVIS was 2.18 (threshold for serious eye damage: IVIS > 55). According to OECD 437, the test item is not categorised as an eye irritant (GHS).

Reference 2

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 December 2016 - 30 January 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye 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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU method B.48 (Isolated chicken eye test method for identifying occular corrosives and severe irritants)

Version / remarks:

2010

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

chicken

Strain:

other: ROSS 308

Details on test animals or tissues and environmental conditions:

Head collection was performed by a slaughter house technician. Heads were removed immediately after sedation of the chickens (sedation was happened by electric current). The heads were transported to Toxi-Coop ZRT. at the earliest convenience for use approximately within 2 hours from collection. The ambient temperature was optimal
(19.4ºC to 20.3ºC) during the transport. All eyes used in the assay were from the same groups of eyes collected on one specific day.
After collection, the heads were inspected for appropriate quality and wrapped with paper moistened with saline, then placed in a plastic box that can be closed (4 5 heads/box).
After removing the head from the plastic box, it was put on soft paper. The eyelids were carefully cut away with scissors, avoiding damaging the cornea. One small drop of fluorescein solution 2 (w/v) % was applied onto the cornea surface for a few seconds and subsequently rinsed off with 20 mL isotonic saline. Then the fluorescein-treated cornea was examined with hand-held slit lamp or slit lamp microscope, with the eye in the head, to ensure that the cornea was not damaged. If the cornea was in good condition, the eyeball was carefully removed from the orbit.
The eyeball was carefully removed from the orbit by holding the nictitating membrane with surgical forceps, while cutting the eye muscles with bent scissors without cutting off the optical nerve too short. The procedure avoided pressure on the eye in order to prevent distortion of the cornea and subsequent corneal opacity. Once removed from the orbit, the eye was placed onto damp paper and the nictitating membrane was cut away with other connective tissue. The prepared eyes were kept on the wet papers in a closed box so that the appropriate humidity was maintained.

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

The test item and positive control applied in an amount of 0.03 g/eye.

Duration of treatment / exposure:

10 seconds

Number of animals or in vitro replicates:

Three test item treated eyes, three positive control and one negative control eyes were used in this study.

Details on study design:

isolated chicken eye test (ICET)

Removal of test item:
The time of application was monitored, then after an exposure period of 10 seconds from the end of the application the cornea surface was rinsed thoroughly with 20 mL saline solution at ambient temperature, while taking care not to damage the cornea but attempting to remove all the residual test item if possible. The eye in the holder was then returned to its chamber. The time while the eye was out of the chamber was limited to the minimum. The Imidazole and test item were stuck on the corneas’ surface in all eyes at 30 minutes after the post-treatment rinse. The gentle rinsing with 20 mL saline was performed in all Imidazole treated eyes after the 30, 75, 120 and 180 minutes of observation, but cornea surfaces were not totally cleared at 240 minutes after the post-treatment rinse. The gentle rinsing with 20 mL saline was performed in all (three eyes) test item treated eyes after the 30 and 75 minutes of observation. All test item treated eyes were totally cleared at 120 minutes after the post-treatment rinse.

Results from corneal opacity, swelling, and fluorescein retention were evaluated separately to generate an ICE (Isolated Chicken Eye) class for each endpoint. The ICE classes for each endpoint were then combined to generate an Irritancy Classification for each test substance.

Irritation parameter:

in vitro irritation score

Run / experiment:

1-3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: The overall ICE class was 3xII.

Remarks:

The overall in vitro classification is neither UN GHS Classification Category I (an ocular corrosive or severe eye irritant) nor No Category. Thus, according to the guideline OECD 438, the test item has been categorised as “No prediction can be made”.

Test Item:

Observation	Value	ICE Class^1
Mean maximum corneal swelling at up to 75 min	10%	II
Mean maximum corneal swelling at up to 240 min	18%	II
Mean maximum corneal opacity	1.3	II
Mean fluorescein retention	1.3	II
Other Observations	None
Overall ICE Class^1	3xII

Positive Control: Imidazole 

Observation	Value	ICE Class^1
Mean maximum corneal swelling at up to 75 min	28%	IV
Mean maximum corneal swelling at up to 240 min	37%	IV
Mean maximum corneal opacity	4.0	IV
Mean fluorescein retention	3.0	IV
Other Observations	Cornea opacity score 4 was observed in two eyes at 30 minutes after the post-treatment rinse.
Overall ICE Class^1	3xIV

The positive control Imidazole was classed as corrosive/severely irritating, UN GHS Classification: Category 1.

 

Negative Control: NaCl (9 g/L saline) 

Observation	Value	ICE Class^1
Mean maximum corneal swelling at up to 75 min	0%	I
Mean maximum corneal swelling at up to 240 min	0%	I
Mean maximum corneal opacity	0.0	I
Mean fluorescein retention	0.5	I
Other Observations	None
Overall ICE Class^1	3xI

The negative control NaCl (9 g/L saline) had no significant effects on the chicken eye in this study.

Positive and negative control values were within the corresponding historical control data ranges.

Interpretation of results:

other: not Category 1 (irreversible effects on the eye) based on GHS criteria

Remarks:

The test item has been categorized as “No prediction can be made”.

Conclusions:

In this ICET, the test item did not cause ocular corrosion or severe irritation in the enucleated chicken eyes (not UN GHS Cat. 1).

Executive summary:

The purpose of this Isolated Chicken Eye Test (ICET) according to OECD guideline 438 was to evaluate the potential ocular corrosivity of the test item by its ability to induce toxicity in enucleated chicken eyes. The test compound was applied in a single dose (30 mg/eye) onto the cornea of isolated chicken eyes in order to potentially classify the test compound as either 1: causing "serious eye damage" (category 1 of the Globally Harmonised System for the Classification and Labelling of Chemicals (GHS)), or 2: not requiring classification for eye irritation or serious eye damage according to the GHS. Tested corneas were evaluated pre-treatment and at approximately 30, 75, 120, 180, and 240 minutes after the post-treatment rinse. The endpoints evaluated were corneal opacity, swelling, fluorescein retention, and morphological effects. All of the endpoints, with the exception of fluorescein retention (which was determined only at pre-treatment and 30 minutes after test substance exposure) were determined at each of the above time points. The test item and Imidazole (positive control) was ground before use in the study and applied in an amount of 30 mg/eye by powdering the entire surface of the cornea attempting to cover the cornea surface uniformly with the test substance or positive control. Three test item treated eyes and three positive control eyes were used in this study. One negative control eye was treated with 30 µL saline solution. After an exposure period of 10 seconds from the end of the application the cornea surface was rinsed thoroughly with about 20 mL saline solution at ambient temperature and this procedure was repeated for each eye.

Adherence of the test item and the positive control Imidazole was observed on the cornea surfaces at 240 min after the post-treatment rinse. Positive and negative controls showed the expected results. The experiment was considered to be valid. The overall ICE class of the test item was 3xII. The test item did not cause ocular corrosion or severe irritation in the enucleated chicken eyes (not UN GHS Cat. 1).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation:

OECD 439:

EpiSkinTMSM test with the test item has been performed to predict its irritation potential by measurement of its cytotoxic effect, as reflected in the MTT assay, according to the OECD Test Guideline No. 439. Disks of EPISKIN (three units) were treated with test item and incubated for 15 minutes at room temperature. Exposure of test material was terminated by rinsing with PBS 1x solution. Epidermis units were then incubated at 37 °C for 42 hours in an incubator with 5% CO2. The viability of each disk was assessed by incubating the tissues for 3 hours with MTT solution at 3 7°C in 5% CO2 protected from light. The precipitated formazan was then extracted using acidified isopropanol and quantified spectrophotometrically. SDS (5% aq.) and 1×PBS treated (three units / positive and negative control) epidermis were used as positive and negative controls respectively. For each treated tissue viability was expressed as a percentage relative to negative control. The test item has an intrinsic colour (black to brownish black), therefore two additional test item treated tissues were used for the non-specific OD evaluation. The test item is also a possible MTT-reducer, therefore additional controls (test item treated killed tissues and negative control treated killed tissues) were used to detect and correct for test substance interference with the viability measurement. As the test item is a possible MTT-reducer and has an intrinsic colour (black to brownish black) to avoid a possible double correction for colour interference, a third control for non-specific colour in killed tissues was performed. Two killed treated tissues were used to avoid a possible double correction for colour interference. The test chemical is identified as requiring classification and labelling according to UN GHS (Category 2 or Category 1), if the mean relative viability after 15 minutes exposure and 42 hours post incubation is less or equal (≤) to 50% of the negative control.

In this in vitro skin irritation test using the EPISKIN model, the test item did not show significantly reduced cell viability in comparison to the negative control (mean viability: 96 %). All obtained test item viability results were above 50 % when compared to the viability values obtained from the negative control. Positive and negative controls showed the expected cell viability values within acceptable limits. The experiment was considered to be valid. The results obtained from this in vitro skin irritation test, indicated that the test item reveals no skin irritation potential under the utilised testing conditions. The test item is considered to be non-irritant to skin and is therefore not classified (UN GHS No Category).

Eye irritation:

OECD 438:

The purpose of the Isolated Chicken Eye Test (ICET) according to OECD guideline 438 was to evaluate the potential ocular corrosivity of the test item by its ability to induce toxicity in enucleated chicken eyes. The test compound was applied in a single dose (30 mg/eye) onto the cornea of isolated chicken eyes in order to potentially classify the test compound as either 1: causing "serious eye damage" (category 1 of the Globally Harmonised System for the Classification and Labelling of Chemicals (GHS)), or 2: not requiring classification for eye irritation or serious eye damage according to the GHS. Tested corneas were evaluated pre-treatment and at approximately 30, 75, 120, 180, and 240 minutes after the post-treatment rinse. The endpoints evaluated were corneal opacity, swelling, fluorescein retention, and morphological effects. All of the endpoints, with the exception of fluorescein retention (which was determined only at pre-treatment and 30 minutes after test substance exposure) were determined at each of the above time points. The test item and Imidazole (positive control) was ground before use in the study and applied in an amount of 30 mg/eye by powdering the entire surface of the cornea attempting to cover the cornea surface uniformly with the test substance or positive control. Three test item treated eyes and three positive control eyes were used in this study. One negative control eye was treated with 30 µL saline solution. After an exposure period of 10 seconds from the end of the application the cornea surface was rinsed thoroughly with about 20 mL saline solution at ambient temperature and this procedure was repeated for each eye.

Adherence of the test item and the positive control Imidazole was observed on the cornea surfaces at 240 min after the post-treatment rinse. Positive and negative controls showed the expected results. The experiment was considered to be valid. The overall ICE class of the test item was 3xII. The test item did not cause ocular corrosion or severe irritation in the enucleated chicken eyes (not UN GHS Cat. 1).

OECD 437:

An in vitro study according to OECD guideline 437 was performed to assess the corneal damage potential of the test item by means of the BCOP assay using fresh bovine corneas. After a first opacity measurement of the fresh bovine corneas (t0), the 20% (w/v) suspension in saline of the test item, the positive, and the negative controls were applied to the different corneas and incubated for 240 minutes at 32± 1 °C. After the incubation phase, the test item as well as the positive and the negative controls were each rinsed from the corneas and opacity was measured again (t240). After the opacity measurements, permeability of the corneas was determined by measuring spectrophotometrically the transfer of sodium fluorescein after incubation in a horizontal position for 90 minutes at 32 ± 1 °C.

For the negative control (saline) neither an increase of opacity nor permeability of the corneas could be observed (mean IVIS =0.86). The positive control (10% (w/v) benzalkonium chloride in saline) showed clear opacity and distinctive permeability of the corneas (mean IVIS = 119.53) corresponding to a classification as serious eye damaging (CLP/EPA/GHS (Cat 1)). The negative control responses resulted in opacity and permeability values that are less than the established upper limits for background opacity and permeability values for bovine corneas treated with the respective negative control. Therefore the acceptability criteria were fulfilled. The test item was tested as suspension. Relative to the negative control, the test item did not cause a relevant increase of the corneal opacity. The calculated mean IVIS was 2.18 (threshold for serious eye damage: IVIS > 55). According to OECD 437, the test item is not categorised as an eye irritant (GHS).

Justification for classification or non-classification

Classification, Labeling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. Based on this data, the substance is not considered to be classified for skin and eye irritation under Regulation (EC) No 1272/2008, as amended for the twelfth time in Regulation (EC) No 2019/521.