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Toxicological information

Eye irritation

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Administrative data

Endpoint:
eye irritation: in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
May 22, 2018 to May25, 2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Data is from experimental study report.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)
Principles of method if other than guideline:
The purpose of this study was to assess potential for the test article to be ocular irritants. The ocular irritation potential of a test article may be predicted by measurement of its cytotoxic effect, as reflected by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, in the MatTek EpiOcular™ model.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
- Name of test material : Diphenyl acetonitrile
- Molecular formula : C14H11N
- Molecular weight : 193.248 g/mol
- Smiles notation : C(c1ccccc1)(c1ccccc1)C#N
- InChl : 1S/C14H11N/c15-11-14(12-7-3-1-4-8-12)13-9-5-2-6-10-13/h1-10,14H
- Substance type: Organic
- Physical state: Solid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL- Source and lot/batch No.of test material: - Lot/batch No.of test material: - Expiration date of the lot/batch:- Purity test date:RADIOLABELLING INFORMATION (Not applicable)- Radiochemical purity: N/A- Specific activity: N/A - Locations of the label: N/A- Expiration date of radiochemical substance: N/ASTABILITY AND STORAGE CONDITIONS OF TEST MATERIAL- Storage condition of test material: Room temperature / Fridge storage- Stability under test conditions: No data available- Solubility and stability of the test substance in the solvent/vehicle: No data available- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No data availableTREATMENT OF TEST MATERIAL PRIOR TO TESTING- Treatment of test material prior to testing: Prior to the main test, the test articles are tested for their ability to reduce/interact with MTT and their ability to stain the tissues itself. All tests are performed according to the by MatTek provided test protocol. - Preliminary purification step (if any): No data available- Final dilution of a dissolved solid, stock liquid or gel: No data available- Final preparation of a solid: No data available FORM AS APPLIED IN THE TEST: SolidOTHER SPECIFICS: No data available

Test animals / tissue source

Species:
human
Strain:
other: Not applicable
Details on test animals or tissues and environmental conditions:
- Description of the cell system used:The normal human-derived keratinocytes were cultured at the air-liquid interface in a chemically defined medium on a permeable polycarbonate insert (surface 0.5 cm2). They were cultured in chemically defined serum free medium to form a multi-layered epithelium similar to that found in native corneal mucosa. Each lot of tissues was Quality Assured by MatTek according to specific QC standards including: histology, tissue viability (MTT mean optical density), reproducibility (SD) and tissue thickness.- Test System IdentificationAll of the EpiOcular™ 3-dimensional human tissues used in this study were identified by the date of arrival and the lot number. Certificate of Analysis for the tissues is included in this report. Tissue plates were appropriately labeled with study information. Bias was not a factor in this test system.- Justification of the test method and considerations regarding applicabilityEpiOcularTM Eye Irritation (OCL) by MatTek In Vitro Life Science Laboratories, Bratislava, SlovakienThe test articles and controls were evaluated for potential ocular irritancy using the EpiOcular™ 3 dimensional human tissue model purchased from MatTek In Vitro Life Science Lab. (Bratislava, Slovakia). The EpiOcular tissue construct is a nonkeratinized epithelium prepared from normal human keratinocytes (MatTek). It models the cornea epithelium with progressively stratified, but not cornified cells. These cells are not transformed or transfected with genes to induce an extended life span in culture. The “tissue” is prepared in inserts with a porous membrane through which the nutrients pass to the cells. A cell suspension is seeded into the insert in specialized medium. After an initial period of submerged culture, the medium is removed from the top of the tissue so that the epithelial surface is in direct contact with the air. This allows the test material to be directly applied to the epithelial surface in a fashion similar to how the corneal epithelium would be exposed in vivo. Each lot of tissues was Quality Assured by MatTek, Inc. according to specific QC standards including: histology (cell layers), tissue viability (MTT mean optical density) and reproducibility (SD).

Test system

Vehicle:
unchanged (no vehicle)
Controls:
other: See ''Remark" for Control Samples used in the study
Amount / concentration applied:
TEST MATERIAL - Amount(s) applied (volume or weight with unit): 50 mg of solid test article - Concentration (if solution): neat (undiluted) VEHICLE (no vehicle) - Amount(s) applied (volume or weight with unit): none - Concentration (if solution): none - Lot/batch no. (if required): none - Purity: noneNEGATIVE CONTROL- Amount(s) applied (volume or weight): 50 µL- Concentration (if solution): neatPOSITIVE CONTROL- Amount(s) applied (volume or weight): 50 µL- Concentration (if solution): neat
Duration of treatment / exposure:
Tissues were exposed for approximately 30 minutes for liquid test article and controls 6 hrs ± 15 min for solid test articles, at approximately 37°C, 5% CO2 in a humidified incubator.
Observation period (in vivo):
Not applicable
Duration of post- treatment incubation (in vitro):
Following the washing step and the post-soak, the tissues were incubated at approximately 37°C, 5% CO2 in a humidified incubator for a post-exposure recovery time of ~2 hours for 18 hrs for solid test articles, or 18 hrs for solid test articles, and controls.
Number of animals or in vitro replicates:
2 tissues were used for test compound and control.
Details on study design:
- Details of the test procedure usedThe tissues were exposed to the test article neat (undiluted). EpiOcular™ tissues were purchased from MatTek. Quality control of the tissues was performed by MatTek and the Certificate of Analysis (CoA) for the tissues is provided and is kept in the study binder. Tissues were exposed for approximately 6 hrs ± 15 min for solid test articles, and controls, at approximately 37°C, 5% CO2 in a humidified incubator. After the exposure, the test article was rinsed off the tissues and the tissues were soaked in media for ~12 minutes for 25 min for solid test articles articles and controls. Following the washing step and the, the tissues were incubated at approximately 37°C, 5% CO2 in a humidified incubator for a post-exposure recovery time totaling ~2 hours for 18 hrs for solid articles and controls. Tissue viability was assessed by 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. - MTT Auto reduction and colouring assessmentMTT Pre-testThe test article was assessed for the potential to interfere with the assay. Approximately 50 µL of liquid test article was added to 1 mL of MTT media (~1 mg/mL) and incubated in a humidified incubator at approximately 37°C and approximately 5% CO2 for 3 hours. 50 µL of ultrapure water was used as a negative control. - Test Article Color TestApproximately 50 µL of liquid test article was added to 1.0 mL of ultrapure water and 2.0 mL isopropanol and incubated in a humidified incubator at approximately 37°C and approximately 5% CO2 for 2 hours, 04 minutes and 35 seconds. Samples were then added to the wells of a clear 96-well plate and the plate was read on a Thermo Scientific Multiskan FC Microplate Photometer to 570 nm. Test articles that tested positive for excessive coloration (OD >0.08) were assessed on living-tissue controls that were incubated in both culture media and MTT media as well (n=3 for both conditions). - MTT Assay Solids: Inserts are removed from the 24-well plate after 3 hrs of incubation and the bottom of the insert is blotted on absorbent material, and then transferred to a pre-labeled 6-well plate containing 1 ml isopropanol in each well so that no isopropanol is flowing into the insert. At the end of the non-submerged extraction inserts and tissues are discarded without piercing and 1 ml of isopropanol is added into each well. The extract solution is mixed and the optical density of the extracted formazan (200 μL/well of a 96-well plate) was determined using aThermo Scientific Multiskan FC Microplate Photometer at 570 nm. Relative cell viability was calculated for each tissue as % of the mean negative control - Evaluation of Test Article in the cell Models1. Cell System: Upon receipt, the MatTek EpiOcular™ tissue cultures were placed in 1.0 mL of fresh Maintenance medium (in a 6-well plate) for 60 minutes. After the 60 minutes incubation, the Maintenance medium was exchanged with fresh medium and the tissues were incubated overnight (16-24 hrs) at approximately 37°C, approximately 5% CO2 in a humidified incubator,2. Control and Test Article Exposures:20 µL of calcium and magnesium free DPBS was added to each tissue and the tissues placed back into the incubator for 30 minutes. The controls and the test article will be applied topically to tissues by pipette. Three tissues will be used per test compound and control.a)Controls: 50 µL of negative control sterile ultrapure water and positive control methyl acetate were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 30 minute exposure time. b)Test Article: When a solid was tested, 50 mg of the solid were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 6 hrs ± 15 min. 3. Post exposure treatment:After the exposure, the tissues were rinsed 20 times with sterile of DPBS to remove test material. The apical surface was gently blotted with a cotton swab and cultures were immediately transferred to a 12-well plate containing 5 mL of media per well. Tissues exposed to solid test articles (and the respective control) were incubated, submerged in the media for ~12 minutes at room temperature.For liquid test articles, tissues, Tissuses were then transferred to 6-well plates containing 1.0 mL fresh Maintenance medium per well and incubated for a post-exposure recovery period for 18 hrs overnight at approximately 37 degC, 5% CO2 in a humidified incubator.- Doses of test chemical and control substances usedTest Article: 50 mg of solid test article were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 6 hrs exposure time Controls: 50 µL of negative control sterile ultrapure water, positive control methyl acetate were added to the tissues. The tissues were placed into the ~37°C humidified incubator with 5% CO2 for the approximately 6 hrs exposure time. - Duration and temperature of exposure, post-exposure immersion and post-exposure incubation periods: Tissues were exposed for approximately 30 minutes for 6 hrs for solid test articles and controls, at approximately 37°C, 5% CO2 in a humidified incubator. Following the washing step and the, the tissues were rinsed and incubated at approximately 37°C, 5% CO2 in a humidified incubator for a post-exposure recovery time totaling ~2 hours for liquid test articles and controls.- Justification for the use of a different negative control than ultrapure H2O (Not applicable)- Justification for the use of a different positive control than neat methyl acetate (Not applicable)- Number of tissue replicates used per test chemical and controls: 2 tissues were used for test compound and control.- Description of the method used to quantify MTT formazanThe blue formazan salt was extracted by submerging tissues in 2 mL isopropanol in a 24-well plate. The extraction for liquid exposed tissues was overnight incubation with a 20 minute 24 second shake the following morning. The optical density of the extracted formazan (200 µL/well of a 96-well plate) was determined using a Thermo Scientific Multiskan FC Microplate Photometer at 570 nm. The blue formazan salt was extracted by placing the tissue insterts in 1 mL isopropanol in a 6-well plate. The extraction for solid exposed tissues was 3 hrs incubation. After an addition of 1 ml isopropanol and mixing, the optical density of the extracted formazan (200μL/well of a 96-well plate) was determined using a Thermo Scientific Multiskan FC Microplate Photometer at 570 nm.- Description of evaluation criteria used including the justification for the selection of the cut-off point for the prediction modelCalculations and Statistical MethodsMTT AssayBlanks: ·  The OD mean from all replicates for each plate (ODblank). Negative Controls (NC): ·  The blank corrected value was calculated: ODNC= ODNCraw– ODblank. ·  The OD mean per NC tissue was calculated. ·  The mean OD for all tissues corresponds to 100% viability. ·  The mean, standard deviation (SD), standard error of the mean (SEM) and the percent coefficient of variation (% CV) was calculated. ODblank= optical density of blank samples (isopropanol alone). ODNCraw= optical density negative control samples. ODNC= optical density of negative control samples after background subtraction. Positive Control (PC): ·        Calculate the blank corrected value: ODPC= ODPCraw– ODblank. ·        The OD mean per PC tissue was calculated. ·        The viability per tissue was calculated: %PC = [ODPC/ mean ODNC] x 100. ·        The mean viability for all tissues was calculated: Mean PC = Σ %PC / number of tissues. ·        The standard deviation (SD), standard error of the mean (SEM) and the percent coefficient of variation (% CV) was calculated. ODPCraw= optical density positive control samples. ODPC= optical density of positive control samples after background subtraction. Tested Articles: ·  Calculate the blank corrected value ODTT= ODTTraw– ODblank. ·  The OD mean per tissue is calculated. ·  The viability per tissue is calculated: %TT = [ODTT/ mean ODNC] x 100. ·  The mean viability for all tissues is calculated: Mean TT = Σ %TT / number of tissues. ·  The standard deviation (SD) and the percent coefficient of variation (% CV)for the controls and the test articles will be calculated. ODTTraw= optical density test article samples. ODPC= optical density of test article samples after background subtraction. Data Correction Procedure for MTT Interfering CompoundsTrue viability = Viability of treated tissue – Interference from test article = ODtvt – ODkt where ODkt = (mean ODtkt – mean ODukt). ODtvt = optical density of treated viable tissue ODkt = optical density of killed tissues ODtkt = optical density of treated killed tissue ODukt = optical density of untreated killed tissue (NC treated tissue) Data Correction Procedure for Colored CompoundsTrue viability = Viability of treated tissue incubated in MTT media – Viability of treated tissue incubated in media without MTT = ODtvt – ODvt. ODtvt = optical density of treated viable tissue incubated in MTT media ODvt = optical density of viable tissues incubated in media alone. Proposed Statistical methods The mean, standard deviation (SD) and the percent coefficient of variation (% CV) for the controls and the test article will be calculated. - Evaluation of data The results of the assay was evaluated and compared to negative control. Table: Irritancy Prediction In VitroResults In VivoPredictionMean tissue viability ≤60% Irritant (I) – Category 1 or 2Mean tissue viability >60% Non-irritant (NI) – No Category- Assay quality controls- Negative Controls (NC)The assay is meeting the acceptance criterion if the mean viability of the NC in terms of Optical Density (OD570) of the NC tissues (treated with sterile ultrapure water) in the MTT assay are >0.8 to <2.5. This is an indicator of tissue viability following shipping and conditions under use.   - Positive Controls (PC)Methyl acetate was used as a PC and tested concurrently with the test article. The assay is meeting the acceptance criteria if the viability of the PC is <50% of the negative control.   - Standard Deviation (SD)Each test of ocular irritancy potential is predicted from the mean viability determined on 3 single tissues. The assay meets the acceptance criteria if SD calculated from individual percent tissue viabilities of the replicates is <18% for three replicate tissues.  

Results and discussion

In vitro

Results
Irritation parameter:
other: mean % tissue viability
Run / experiment:
Run 1
Value:
106.8
Vehicle controls validity:
not specified
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
no indication of irritation
Other effects / acceptance of results:
The MTT data show the assay quality controls were met. The MTT data show the assay quality controls were met, as the OD of the negative control tissues was between 0.981 and 1.284 in run 1. Also, the positive control, methyl acetate, reduced tissue viability to be 22.1% (for 30 minute exposures with liquids) of negative control in run one and the standard deviation (SD) calculated from individual percent tissue viabilities of the test article exposed replicates was D > 20 passing the acceptance criteria. met.

Other: Passing criteria was > 20 D

Applicant's summary and conclusion

Interpretation of results:
other: not irritating
Conclusions:
The ocular irritation potential of test article was determined according to the OECD 492 test guideline followed for this study. The mean % tissue viability of test substance Diphenyl acetonitrile (CAS No: 86-29-3)was determined to be 106.8%. Thus, Diphenyl acetonitrile (CAS No: 86-29-3) was considered to be not irritating to the human eyes.
Executive summary:

The ocular irritation potential of test article was determined according to the OECD 492 test guideline for this study. The MatTek EpiOcular™ model was used to assess the potential ocular irritation of the test articles by determining the viability of the tissues following exposure to the test article via MTT.  Tissues were exposed to solid test articles and control for approx.6 hours, followed by a 25 minute post-soak and approximately 18 hours recovery after the post-soak.  The viability of each tissue was determined by MTT assay. 

 

The MTT data show the assay quality controls were met, and passing the acceptance criteria.

 

The mean % tissue viability of test substance Diphenyl acetonitrile (CAS No: 86-29-3) was determined to be 106.8 %.

 

Hence, under the experimental test conditions it was concluded that test substance Diphenyl acetonitrile (CAS No: 86-29-3) was considered to be not irritating to the human eyes and can thus be “Not classified’’ as per CLP Regulation.