1,3-phenylenebis((4-hydroxyphenyl)methanone)

Endpoint summary

Description of key information

- Skin corrosion / irritation: not corrosive (OECD 431, GLP, K, rel.1), not irritant (OECD 439, GLP, K, rel.1)

- Eye irritation/damage: not classified (OECD 437, GLP, K, rel. 1)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 September 2017 - 13 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study has been performed according to OECD and/or EC guidelines and acc ording to GLP principles.

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 29 July 2016

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EC Guideline No. 440/2008. Part B: Methods for the Determination of Toxicity and other health effects, Guideline B.40 BIS: "In Vitro Skin Corrosion: Human Skin Model Test".

Version / remarks:

Official Journal of the European Union No. L142, 31 May 2008.

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Specific details on test material used for the study:

- Appearance: Off white crystalline powder
- Test item storage: At room temperature
- Stable under storage conditions until: 15 May 2018 (expiry date)

Test system:

human skin model

Remarks:

EpiDerm Skin Model

Source species:

human

Cell type:

other: Adult human-derived epidermal keratinocytes

Cell source:

other: MatTek Corporation, Ashland MA, U.S.A.

Justification for test system used:

Recommended test system in international guidelines (OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm Skin Model, EPI-200
- Tissue batch number(s): 27144 Kit I and Kit J

TEMPERATURE USED FOR TEST SYSTEM
- Temperature of pre-incubation: 37°C
- Temperature used during treatment / exposure: 3 minutes or 1 hour at room temperature (26.4-27.6°C)
- Temperature of post-treatment incubation: 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: Volume of phosphate buffered saline and number of washing steps not specified
- Observable damage in the tissue due to washing: None
- Modifications to validated SOP: None

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT concentrate (5 mg/ml) diluted (1:5) with MTT diluent (supplemented DMEM)
- Incubation time: 3 hours at 37°C in air containing 5% CO2
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: MTT QC assay, 4 hours, n=3: OD (540-570 nm)= 1.989+/-0.122 [Acceptance criteria: 1.0-3.0]
- Barrier function: ET-50 assay, 100 µL 1% Triton X-100, 4 time-points, n=3, MTT assay: ET-50= 6.21 hrs [Acceptance criteria: 4.77-8.72 hrs]
- Morphology: Presence of a functional stratum corneum, a viable basal cell layer, and intermediate spinous and granular layers
- Contamination: No contamination

NUMBER OF REPLICATE TISSUES: 4 (Two tissues were used for a 3-minute exposure to the test item and two for a 1-hour exposure) or 2 (2 tissues for negative control and 2 tissues for positive control)

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- None, the test item did not interfere with the MTT endpoint.

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 3

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- A test item is considered corrosive in the in vitro skin corrosion test if:
a) The relative mean tissue viability obtained after 3-minute treatment compared to the negative control tissues is decreased below 50%.
b) In addition, a test item considered non-corrosive (viability >= 50%) after the 3-minute treatment is considered corrosive if the relative tissue viability after 1-hour treatment with the test item is decreased below 15%.
- A test item is considered non corrosive in the in vitro skin corrosion test if:
a) The relative mean tissue viability obtained after the 3-minute treatment compared to the negative control tissues is not decreased below 50%.
b) In addition, the relative tissue viability after the 1-hour treatment is not decreased below 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 28.2 to 32.8 mg of the solid test item directly applied on top of the skin tissue after moisture with 25 µl Milli-Q water.

VEHICLE
- No vehicle

NEGATIVE CONTROL
- Amount(s) applied: 50 µL

POSITIVE CONTROL
- Amount(s) applied: 50 µL
- Concentration: 8.0 N

Duration of treatment / exposure:

3 minutes or 1 hour

Number of replicates:

4 (two tissues for a 3-minute exposure to the test item and two for a 1-hour exposure) or 2 (two tissues for negative control and two tissues for positive control)

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3-minute exposure

Value:

114

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

100%

Positive controls validity:

valid

Remarks:

11%

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1-hour exposure

Value:

104

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

100%

Positive controls validity:

valid

Remarks:

7.6%

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: No
- Direct-MTT reduction: No
- Colour interference with MTT: No

DEMONSTRATION OF TECHNICAL PROFICIENCY: Yes

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes [mean OD570 of the two tissues within the laboratory historical control data range: 1.324-2.615 (3-minute exposure) or 1.361-2.352 (1-hour exposure)]
- Acceptance criteria met for positive control: Yes [mean relative viability following 1-hour exposure < 15%]
- Acceptance criteria met for variability between replicate measurements: Yes [in the range 20 - 100% viability, CV =< 30%]
- Range of historical values if different from the ones specified in the test guideline:
Negative control (3-minute treatment, OD570): 1.324 - 2.615
Negative control (1-hour treatment, OD570): 1.361 - 2.352
Positive control (3-minute treatment, OD570): 0.0172 - 0.56
Positive control (1-hour treatment, OD570): 0.046 - 0.339
Historical data range obtained by collecting all data over the period of November 2013 to November 2016.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the test substance, 1,3-Bis (4-hydroxy benzoyl) benzene, is not corrosive to the skin.

Executive summary:

The assessment of the corrosive potential to skin of 1,3-Bis (4-hydroxy benzoyl) benzene was carried out in compliance with GLP, using an in vitro skin corrosive test based on the guidelines described in: OECD No. 431 (adopted 29 July 2016) and EU Method B.40 BIS.

The test consisted of topical application of 1,3-Bis (4-hydroxy benzoyl) benzene (28.2 to 32.8 mg of the solid test item with 25 µl Milli-Q water) on the skin tissue for 3-minute and 1 -hour exposure. After exposure the skin tissue was thoroughly rinsed to remove the test item followed by immediate determination of the cytotoxic (corrosive) effect.

Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) at the end of the treatment.

The test item did not interfere with the MTT endpoint. The positive control (Potassium hydroxide) had a mean relative tissue viability of 7.6 % after the 1-hour exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control (Milli-Q water) tissues was within the acceptance limits of OECD 431 (lower acceptance limit ≥0.8 and upper acceptance limit =< 2.8) and the laboratory historical control data range (actual range 1.4955 – 1.8957). In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was =< 13%, indicating that the test system functioned properly.

The relative mean tissue viability obtained after the 3-minute and 1-hour treatments with 1,3 -Bis (4 -hydroxy benzoyl) benzene compared to the negative control tissues was 114% and 104% respectively.

Because the mean relative tissue viability for 1,3 -Bis (4 -hydroxy benzoyl) benzene was not below 50% after 3 minutes treatment and not below 15% after 1 hour treatment, 1,3-Bis (4-hydroxy benzoyl) benzene is considered to be non-corrosive in the performed experiment.

The substance is not classified as corrosive to skin according to UN-GHS criteria.

Reference 2

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 November 2017 - 17 January 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study has been performed according to OECD and/or EC guidelines and acc ording to GLP principles.

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Adopted 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:

20 July 2012

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Appearance: Off white crystalline powder
- Test item storage: At room temperature
- Stable under storage conditions until: 15 May 2018 (expiry date)

Test system:

human skin model

Remarks:

EPISKIN Small Model (EPISKIN-SM, 0.38 cm2)

Source species:

human

Cell type:

other: Adult human-derived epidermal keratinocytes

Cell source:

other: SkinEthic Laboratories, Lyon, France

Justification for test system used:

Recommended test system in international guidelines (OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN Small Model (EPISKIN-SM, 0.38 cm2)
- Tissue batch number(s): 17 EKIN 045
- Expiration date: 13 November 2017

TEMPERATURE USED FOR TEST SYSTEM
- Temperature of pre-incubation: 37°C
- Temperature used during treatment / exposure: 15 minutes at room temperature
- Temperature of post-treatment incubation: 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: Volume of phosphate buffered saline and number of washing steps not specified
- Observable damage in the tissue due to washing: None
- Modifications to validated SOP: None

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL in PBS
- Incubation time: 3 hours at 37°C
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Histology scoring= 23.3+/-0.3 [Acceptance criteria: >= 19.5]
- IC50 determination= 2.3 mg/mL [Acceptance criteria: 1.5-3.0 mg/mL]
- Morphology: Well differentiated epidermis consisting of a basal layer, several spinous and granular layers and a thick stratum corneum.
- Contamination: No contamination

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- None, the test item did not interfere with the MTT endpoint.

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 2

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- A test item is considered irritant in the skin irritation test if:
The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test itema nd 42 hours of post incubation is ≤ 50% of the mean viability of the negative controls.
- A test item is considered non-irritant in the in vitro skin irritation test if:
The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is > 50% of the mean viability of the negative controls.

Control samples:

yes, concurrent vehicle

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 21.55 to 30.76 mg of the solid test item directly applied on top of the skin tissue after moisture with 5 µl Milli-Q water.

VEHICLE
- No vehicle

NEGATIVE CONTROL
- Amount(s) applied: 25 µL

POSITIVE CONTROL
- Amount(s) applied: 25 µL
- Concentration: 5%

Duration of treatment / exposure:

15 ± 0.5 minutes

Duration of post-treatment incubation (if applicable):

42 hours

Number of replicates:

3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

15-minute exposure

Value:

99

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

100%

Positive controls validity:

valid

Remarks:

7.0%

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: No
- Direct-MTT reduction: No
- Colour interference with MTT: No

DEMONSTRATION OF TECHNICAL PROFICIENCY: Yes

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes [mean OD570 of the three tissues within the laboratory historical control data range: 0.422-1.547 and SD of the % viability =< 18]
- Acceptance criteria met for positive control: Yes [mean relative viability =< 50% and SD of the % viability =< 18]
- Acceptance criteria met for variability between replicate measurements: Yes [SD from individual % tissue viabilitiesof the three identically treated replicates =< 18]
- Range of historical values if different from the ones specified in the test guideline:
Negative control (OD570): 0.422 - 1.547
Positive control (OD570): 0.023 - 0.437
Historical data range obtained by collecting all data over the period of November 2014 to November 2017.

Interpretation of results:

GHS criteria not met

Conclusions:

Under the test conditions, the test substance, 1,3-Bis (4-hydroxy benzoyl) benzene is non-irritant in the in vitro skin irritation test.

Executive summary:

The assessment of the skin irritation potential of 1,3-Bis (4-hydroxy benzoyl) benzene was carried out, under GLP compliance, using an in vitro skin irritation test based on the guidelines described in: OECD No. 439 (adopted 28 July 2015) and EU Method B.46 (Amended by EC No. 640/2012 OJ No. L193, 20 July 2012).

The test consisted of topical application of 1,3-Bis (4-hydroxy benzoyl) benzene (21.55 to 30.76 mg of the solid test item with 5 µl Milli-Q water) on the skin tissue for 15 minutes. After exposure the skin tissue was thoroughly rinsed to remove the test item and transferred to fresh medium. After a 42 hour incubation period, determination of the cytotoxic (irritancy) effect was performed.

Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) at the end of the treatment.

The positive control had a mean cell viability of 7% after 15 ± 0.5 minutes exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was <8%, indicating that the test system functioned properly.

The relative mean tissue viability obtained after the 15 -minute treatment with 1,3-Bis (4-hydroxy benzoyl) benzene compared to the negative control tissues was 99%.

Since the mean relative tissue viability for the test item was above 50%, 1,3 -Bis (4 -hydroxy benzoyl) benzene is considered to be non-irritant.

Finally, 1,3-Bis (4-hydroxy benzoyl) benzene is non-irritant in the in vitro skin irritation test under the experimental conditions described in this report and should not be classified according to the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) of the United Nations.

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:

06 October 2017 - 13 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

The study has been performed according to OECD and/or EC guidelines and acc ording to GLP principles.

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:

adopted July 26, 2013

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Appearance: Off white crystalline powder
- Test item storage: At room temperature
- Stable under storage conditions until: 15 May 2018 (expiry date)

Species:

cattle

Strain:

not specified

Details on test animals or tissues and environmental conditions:

SOURCE OF COLLECTED EYES
- Source: Bovine eyes from young cattle were obtained from the slaughterhouse (Vitelco, -'s Hertogenbosch, The Netherlands)
- Number of animals: Not specified
- Characteristics of donor animals (e.g. age, sex, weight): Not specified
- Storage, temperature and transport conditions of ocular tissue: Eyes were collected and transported in physiological saline in a suitable container under cooled conditions.
- Time interval prior to initiating testing: Not specified

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): 337.1 to 402.6 mg
- Concentration (if solution): Undiluted

Duration of treatment / exposure:

240 +/- 10 minutes at 32 +/- 1°C

Number of animals or in vitro replicates:

3 corneas were selected at random for each treatment group

Details on study design:

SELECTION AND PREPARATION OF CORNEAS
The eyes were checked for unacceptable defects, such as opacity, scratches, pigmentation and neovascularization by removing them from the physiological saline and holding them in the light. Those exhibiting defects were discarded.
The isolated corneas were stored in a petri dish with cMEM (Earle’s Minimum Essential Medium (Life Technologies, Bleiswijk, The Netherlands) containing 1% (v/v) L-glutamine (Life Technologies) and 1% (v/v) Foetal Bovine Serum (Life Technologies)). The isolated corneas were mounted in a corneal holder (one cornea per holder) of BASF (Ludwigshafen, Germany) with the endothelial side against the O-ring of the posterior half of the holder. The anterior half of the holder was positioned on top of the cornea and tightened with screws.
The compartments of the corneal holder were filled with cMEM of 32 +/- 1°C. The corneas were incubated for the minimum of 1 hour at 32 +/- 1°C.

QUALITY CHECK OF THE ISOLATED CORNEAS
After the incubation period, the medium was removed from both compartments and replaced with fresh cMEM. Opacity determinations were performed on each of the corneas using an opacitometer (BASF-OP3.0, BASF, Ludwigshafen, Germany). The opacity of each cornea was read against a cMEM filled chamber, and the initial opacity reading thus determined was recorded. Corneas that had an initial opacity reading higher than 7 were not used.

NUMBER OF REPLICATES
3 corneas were selected at random for each treatment group

NEGATIVE CONTROL USED
physiological saline (Eurovet Animal Health, Bladel, The Netherlands)

POSITIVE CONTROL USED
Imidazole 20% (w/v) (Merck Schuchardt OHG, Germany)

APPLICATION DOSE AND EXPOSURE TIME
The medium from the anterior compartment was removed and 750 µl of the negative control and 20% (w/v) Imidazole solution (positive control) were introduced onto the epithelium of the cornea. 1,3-Bis (4-hydroxy benzoyl) benzene was weighed in a bottle and applied directly on the corneas in such a way that the cornea was completely covered (337.1 to 402.6 mg). The holders were slightly rotated, with the corneas maintained in a horizontal position, to ensure uniform distribution of the control or the test item over the entire cornea. Corneas were incubated in a horizontal position for 240 +/- 10 minutes at 32 +/- 1°C.

TREATMENT METHOD: closed chamber

POST-INCUBATION PERIOD: no

REMOVAL OF TEST SUBSTANCE
After the incubation the solutions and the test compound were removed and the epithelium was washed at least three times with MEM with phenol red (Earle’s Minimum Essential Medium Life Technologies). Possible pH effects of the test item on the corneas were recorded. Each cornea was inspected visually for dissimilar opacity patterns. The medium in the posterior compartment was removed and both compartments were refilled with fresh cMEM and the opacity determinations were performed.

METHODS FOR MEASURED ENDPOINTS:
- Corneal opacity:
The opacity of a cornea was measured by the diminution of light passing through the cornea. The light was measured as illuminance (I = luminous flux per area, unit: lux) by a light meter.
The opacity value (measured with the device OP-KIT) was calculated according to:

Opacity = [(I0/I) -0.9894] / 0.0251

With I0 the empirically determined illuminance through a cornea holder but with windows and medium, and I the measured illuminance through a holder with cornea.
The change in opacity for each individual cornea (including the negative control) was calculated by subtracting the initial opacity reading from the final post-treatment reading. The corrected opacity for each treated cornea with the test item or positive control was calculated by subtracting the average change in opacity of the negative control corneas from the change in opacity of each test item or positive control treated cornea.
The mean opacity value of each treatment group was calculated by averaging the corrected opacity values of the treated corneas for each treatment group.

- Corneal permeability:
Following the final opacity measurement, permeability of the cornea to Na-fluorescein (Sigma-Aldrich, Germany) was evaluated.
The medium of both compartments (anterior compartment first) was removed. The posterior compartment was refilled with fresh cMEM. The anterior compartment was filled with 1 mL of 5 mg Nafluorescein (Sigma-Aldrich Chemie GmbH, Germany)/ml cMEM solution.
The holders were slightly rotated, with the corneas maintained in a horizontal position, to ensure uniform distribution of the sodium-fluorescein solution over the entire cornea. Corneas were incubated in a horizontal position for 90 +/- 5 minutes at 32 +/- 1°C.
After the incubation period, the medium in the posterior compartment of each holder was removed and placed into a sampling tube labelled according to holder number. 360 μl of the medium from each sampling tube was transferred to a 96-well plate. The optical density at 490 nm (OD490) of each sampling tube was measured in triplicate using a microplate reader (TECAN Infinite® M200 Pro Plate Reader). Any OD490 that was 1.500 or higher was diluted to bring the OD490 into the acceptable range (linearity up to OD490 of 1.500 was verified before the start of the experiment). OD490 values of less than 1.500 were used in the permeability calculation.
The mean OD490 for each treatment was calculated using cMEM corrected OD490 values.
If a dilution has been performed, the OD490 of each reading of the positive control and the test item was corrected for the mean negative control OD490 before the dilution factor was applied to the reading.

- Others (e.g, pertinent visual observations, histopathology): Additionally the opacity and permeability values were evaluated independently to determine whether the test item induced irritation through only one of the two endpoints.

SCORING SYSTEM: In Vitro Irritancy Score (IVIS) = mean opacity value + (15 x mean OD490 value)

DECISION CRITERIA:
The IVIS cut-off values for identifying the test items as inducing serious eye damage (UN GHS Category 1) and test items not requiring classification for eye irritation or serious eye damage (UN GHS No Category) are given hereafter:

In vitro score range: UN GHS:
=< 3 No Category
> 3 ; =< 55 No prediction can be made
> 55 Category 1

ACCEPTABILITY CRITERIA
The assay is considered acceptable if:
- The positive control gives an in vitro irritancy score that falls within two standard deviations of the current historical mean.
- The negative control responses should result in opacity and permeability values that are less than the upper limits of the laboratory historical range.

Irritation parameter:

in vitro irritation score

Run / experiment:

1

Value:

0.6

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

2.8

Positive controls validity:

valid

Remarks:

150

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: The corneas treated with the positive control were turbid after the 240 minutes of treatment whereas those treated with 1,3-Bis (4-hydroxy benzoyl) benzene appeared clear after treatment.

DEMONSTRATION OF TECHNICAL PROFICIENCY: Yes

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes
- Range of historical values if different from the ones specified in the test guideline:
IVIS for the negative control, historical control data: -5.3 - 5.3 (data range obtained by collecting all data over the period of Aug 2014 to Aug 2017).
Opacity for the negative control, historical data: -5.4 - 5.2 (data range obtained by collecting all data over the period of Aug 2014 to Aug 2017).
Permeability for the negative control, historical data: -0.010 - 0.205 (data range obtained by collecting all data over the period of Aug 2014 to Aug 2017).
IVIS for the positive control, historical control data: 86.5 - 211.4 (data range obtained by collecting all data over the period of Aug 2014 to Aug 2017).

Interpretation of results:

GHS criteria not met

Conclusions:

Under the experimental conditions of this study, 1,3-Bis (4-hydroxy benzoyl) benzene induced an IVIS =< 3, therefore, the test substance is not classified for eye irritation or serious eye damage, according to Regulation (EC) No. 1272/2008 (CLP) and to the UN-GHS Regulation.

Executive summary:

The eye hazard potential of the 1,3-Bis (4-hydroxy benzoyl) benzene was evaluated using the Bovine Corneal Opacity and Permeability test (BCOP test), under GLP compliance, according to the OECD Guideline No. 437.

The corneal damage potential of test substance was assessed using fresh bovine corneae. 337.1 to 402.6 mg of test item was directly applied to cornea for 240 minutes at 32 ± 1 °C and corneal opacity was measured. Three corneas were used for each treated series (undiluted test item; negative control: physiological saline; positive control: imidazole). Following the opacity measurement, the permeability of the corneas to sodium fluorescein was evaluated. Two endpoints, corneal opacity and permeability, were measured and combined to give an In Vitro Irritancy Score.

The individual in vitro irritancy scores for the negative controls ranged from 0.8 to 4.7. The individual positive control in vitro irritancy scores ranged from 112 to 199. The corneas treated with the positive control were turbid after the 240 minutes of treatment. The mean in vitro irritancy score of the positive control was 150 and within two standard deviations of the current historical positive control mean (86.5 - 211.4). One of the negative control eyes was excluded from the analysis since the permeability (0.558) was above the historical database (-0.010 - 0.205) which resulted in an IVIS outside the historical data base. Since the other two eyes completely met the criteria and the test item results were not influenced by this result, this does not affect the study outcome (Study Plan deviation). It was therefore concluded that the test conditions were adequate and that the test system functioned properly.

The corneas were clear after the 240 minutes of treatment with 1,3-Bis (4-hydroxy benzoyl) benzene. No pH effect of the test item was observed on the rinsing medium. Hence, the in vitro irritancy scores ranged from -0.3 to 1.8 after 240 minutes of treatment with 1,3-Bis (4-hydroxy benzoyl) benzene and, the mean IVIS was lower than or equal to 3.

The test substance, 1,3-Bis (4-hydroxy benzoyl) benzene, is not classified for eye irritation or serious eye damage, according to Regulation (EC) No. 1272/2008 (CLP) and to the UN-GHS Regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation/corrosion:

Two key studies were identified for the skin irritation / corrosion.

A key study (CRL, 2017, Rel.1) was performed to evaluate the corrosive potential of the test substance for skin. This in vitro skin corrosion study was performed according to the OECD Guideline 431 and EU Method B.40 BIS and in compliance with GLP, using the EpiDerm™ Human Skin Model. The relative mean tissue viability obtained after the 3-minute and 1-hour treatments with 1,3 -Bis (4 -hydroxy benzoyl) benzene compared to the negative control tissues was 114% and 104% respectively. The quality criteria required for acceptance of results in the test were satisfied. With a tissue viability > 50% after 3 minutes of exposure and > 15% after 60 minutes of exposure, the test material was considered not to be corrosive to skin.

A key study (CRL, 2018, Rel.1) was performed to evaluate the irritant potential of the test substance for skin. This in vitro skin irritation study was performed according to the OECD Guideline 439 and EU Method B.46, and in compliance with GLP, using the EPISKIN™ Reconstructed Human Epidermis Model. The relative mean tissue viability obtained after the 15-minute treatment with 1,3-Bis (4-hydroxy benzoyl) benzene followed by 42 hour posttreatment incubation compared to the negative control tissues was 99%. The quality criteria required for acceptance of results in the test were satisfied. Since the mean relative tissue viability for the test item was above 50%, the test material was considered as non-irritant to skin.

Eye irritation:

A key study was identified for eye irritation.

This BCOP assay (CRL, 2017, Rel.1) was performed according to the OECD Guideline 437 and in compliance with GLP, using bovine corneas. The quality criteria required for acceptance of results in the test were satisfied. The corneas were clear after the 240 minutes of treatment with 1,3-Bis (4-hydroxy benzoyl) benzene. No pH effect of the test item was observed on the rinsing medium. Hence, the in vitro irritancy scores ranged from -0.3 to 1.8 after 240 minutes of treatment with 1,3-Bis (4-hydroxy benzoyl) benzene and, the mean IVIS was lower than or equal to 3. Therefore, the test substance, 1,3-Bis (4-hydroxy benzoyl) benzene, is not considered to induce eye irritation or serious eye damage.

Respiratory irritation:

No study was available.

Justification for classification or non-classification

Harmonized classification:

The substance has no harmonized classification according to the Regulation (EC) No. 1272/2008.

Self-classification:

Based on the available data no additional self-classification is proposed for the substance regarding skin and eye irritation according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP) and to the UN-GHS.

No data was available regarding respiratory irritation, however the substance not being classified for skin and eye irritation, no classification is expected for respiratory irritation.