Benzoic acid, 2-([1,1'-biphenyl]-4-ylcarbonyl)-

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From March 04, 2014 to May 18, 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-{[1,1'-biphenyl]-4-carbonyl}benzoic acid

EC Number:

700-862-4

Cas Number:

42797-18-2

Molecular formula:

C20 H14 O3

IUPAC Name:

2-{[1,1'-biphenyl]-4-carbonyl}benzoic acid

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material (as cited in study report): 2-(4Phenylbenzoyl)benzoic acid
- Physical state: white powder
- Analytical purity: 99.9%
- Lot/batch No.: 5307
- Expiration date of the lot/batch: 01 May 2015
- Storage condition of test material: room temperature in the dark

Specific details on test material used for the study:

Batch No.: 5307; Purity: 99.9%; Appearance: white powder

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: EPISKIN model - reconstructed human epidermis

Details on test system:

EPISKIN Reconstructed Human Epidermis Model Kit
Supplier: SkinEthic Laboratories, Lyon, France
Date received: 04 March 2014
EpiSkin Tissues (0.38 cm2) lot number: 14-EKIN-007
Maintenance Medium lot number: 14-MAIN3-009
Assay Medium lot number: 14-ESSC-008

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

10 mg (26.3 mg/cm2) of the test substance was applied to the epidermal surface.
Triplicate tissues treated with 10 μL of DPBS served as the negative controls and triplicate tissues treated with 10 μL of SDS 5% w/v served as the positive controls. To ensure satisfactory contact with the positive control substance, the SDS solution was spread over the entire surface of the epidermis using a pipette tip (taking particular care to cover the centre). After 7-Minutes contact time the SDS solution was re-spread with a pipette tip to maintain the distribution of the SDS for the remainder of the contact period. The plates were kept in the biological safety cabinet at room temperature for 15 min.

Duration of treatment / exposure:

15 min

Duration of post-treatment incubation (if applicable):

42 h

Number of replicates:

Triplicates for the test substance, positive and negative control

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Value:

99.7

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

Direct MTT Reduction
The MTT solution containing the test substance did not turn blue which indicated that the test substance did not directly reduce MTT.

Test substance
The relative mean viability of the test substance treated tissues was 99.7% after a 15 min exposure period and 42 h post-exposure incubation period.
It was considered unnecessary to perform IL-1a analysis as the results of the MTT test were unequivocal.

Quality Criteria
The relative mean tissue viability for the positive control treated tissues was 7.5% relative to the negative control treated tissues and the standard deviation value of the percentage viability was 1.8%. The positive control acceptance criterion was therefore satisfied.
The mean OD 562 for the negative control treated tissues was 0.926 and the standard deviation value of the percentage viability was 1.7%. The negative control acceptance criterion was therefore satisfied.
The standard deviation calculated from individual percentage tissue viabilities of the three identically test substance treated tissues was 5.1%. The test substance acceptance criterion was therefore satisfied.

Applicant's summary and conclusion

Interpretation of results:

other: CLP criteria not met

Conclusions:

Under the study conditions, the test substance was concluded to be non-irritating to skin.

Executive summary:

An in vitro study was conducted to determine the skin irritation potential of the test substance PBBA according to OECD Guideline 439 and EU Method B.46, in compliance with GLP. Skin irritation potential was examined using the EPISKIN reconstructed human epidermis model following a treatment period of 15 min and a post-exposure incubation period of 42 h. The principle of the assay is based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test substance by means of the colorimetric MTT reduction assay. Cell viability is measured by enzymatic reduction of the yellow MTT tetrazolium salt to a blue formazan salt in the substance treated tissues relative to the negative controls. To identify possible interference of the test substance with the MTT endpoint, the test substance was checked for the ability to directly reduce MTT prior to the main assay. On the day of the main test, triplicate tissues were treated with the test substance for an exposure period of 15 min. At the end of the exposure period, each tissue was rinsed before incubating for 42 h at 37°C, 5% CO2 in air. Formazan extraction was performed at Day 3. At the end of the post-exposure incubation period, each tissue was taken for MTT-loading. Thereafter, a total biopsy of each epidermis was made and placed into micro-tubes containing acidified isopropanol for extraction of formazan crystals out of the MTT-loaded tissues. Absorbance or optical density measurements were conducted at Day 6. The optical density was measured at 562 nm. The relative mean viability of the test substance treated tissues was 99.7%, which is well above the non-irritant viability limit of >50%. Under the study conditions, the test substance is concluded to be non-irritating to skin (Warren, 2014).