Reaction mass of butanoic acid, 2-ethyl-2,3,3-trimethyl-, ethyl ester and butanoic acid, 2,3-dimethyl-2-(1-methylethyl)-, ethyl ester and pentanoic acid, 2,2,4,4-tetramethyl-, ethyl ester and ethyl 2,2,3,3-tetramethylpentanoate and ethyl 2,2,3,4-tetramethylpentanoate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2020

Report date:

2020

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

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)

Version / remarks:

2019-06-18

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Guidance document on integrated approaches to testing and assessment (IATA) for serious eye damage and eye irritation, Series on Testing and Assessment No. 263

Version / remarks:

2019-07-05

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

BASF SE, Experimental Toxicology and Ecology, 67056 Ludwigshafen, Germany

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

liquid

Test animals / tissue source

Species:

human

Details on test animals or tissues and environmental conditions:

- Justification of the test method and considerations regarding applicability: This Test Guideline describes an in vitro procedure allowing the identification of chemicals not requiring classification and labelling for eye irritation or serious eye damage in accordance with UN GHS. The reconstructed human cornea-like epithelium (RhCE) closely mimics the histological, morphological, biochemical and physiological properties of the human corneal epithelium and has been validated, considered scientifically valid and adopted as OECD test Guideline.

- Description of the cell system used: The EpiOcularTM model (OCL-200) is a three-dimensional, non-keratinized tissue construct composed of normal human-derived, epidermal keratinocytes used to model the human corneal epithelium. The EpiOcularTM tissues are cultured on cell culture inserts.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount applied (volume or weight with unit): 50 µL of undiluted test substance

VEHICLE
- Amount applied (volume or weight with unit): 50 µL

Duration of treatment / exposure:

Pre-treatment of tissues: 30 minutes with PBS
Application of the test substance/controls: 30 minutes

Duration of post- treatment incubation (in vitro):

12 minutes post-soak immersion and 2 hours post-incubation period

Number of animals or in vitro replicates:

2 tissues

Details on study design:

- Details of the test procedure used
- RhCE tissue construct used: EpiOcula model (OCL-200), MatTek In Vitro Life Science Laboratories, Bratislava, Slovakia (Lot No: 30637)

- Duration and temperature of exposure, post-exposure immersion and post-exposure incubation periods: Exposure for 30 minutes at 37°C, post-exposure immersion for 12 minutes in pre-warmed medium and post-incubation period for 2 hours at 37°C, incubation with MTT solution for 3 hours at 37°C.

- Indication of controls used for direct MTT-reducers: The test substance was added to 0.9 mL MTT solution. The mixture was incubated in the dark at about 37°C for 3 hours. A negative control (deionized water) was tested concurrently. As no MTT reduction occurs, no freeze-killed control tissues (KC) are included in the main test.

- Number of tissue replicates used per test chemical and controls: 2 tissues were treated with each the test substance, positive and negative control

- Wavelength used for quantifying MTT formazan: 570 nm (optical density) without reference filter using a SunriseTM Absorbance Reader

- Description of the method used to quantify MTT formazan: Optical density, for data evaluation see section "DATA EVALUATION" in "Any other information on materials and methods incl. tables".

- Description of evaluation criteria used including the justification for the selection of the cut-off point for the prediction model: See "Any other information on materials and methods incl. tables" section.

- Reference to historical positive and negative control results demonstrating suitable run acceptance criteria: See section "ACCEPTANCE CRITERIA" in "Any other information on materials and methods incl. tables".

- Positive and negative control means and acceptance ranges based on historical data: See section "ACCEPTANCE CRITERIA" in "Any other information on materials and methods incl. tables".

- Acceptable variability between tissue replicates for positive and negative controls: See section "ACCEPTANCE CRITERIA" in "Any other information on materials and methods incl. tables".

- Acceptable variability between tissue replicates for the test chemical: See section "ACCEPTANCE CRITERIA" in "Any other information on materials and methods incl. tables".

Results and discussion

In vitro

Results

Results 1

Irritation parameter:

other: Relative tissue viability [% of NC]

Run / experiment:

mean of 2 tissues

Value:

79

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation parameter:

other: Relative tissue viability [% of NC]

Run / experiment:

tissue 1

Value:

78.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 3

Irritation parameter:

other: Relative tissue viability [% of NC]

Run / experiment:

tissue 2

Value:

79.1

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes.
- Acceptance criteria met for positive control: Yes.

The test substance is not able to reduce MTT directly.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met