p-toluic acid

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 October to 01 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

not specified

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

p-toluic acid

EC Number:

202-803-3

EC Name:

p-toluic acid

Cas Number:

99-94-5

Molecular formula:

C8H8O2

IUPAC Name:

4-methylbenzoic acid

Test material form:

solid: crystalline

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Bx 20170320
- Expiration date of the lot/batch: 20 March 2018
- Purity test date:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature (15-25°C, ≤70% Relative Humidity, RH), protected from humidity (tight closed container), protected from light.
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle:
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing:
- Preliminary purification step (if any):
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid:

FORM AS APPLIED IN THE TEST (if different from that of starting material)

TYPE OF BIOCIDE/PESTICIDE FORMULATION (if applicable)

OTHER SPECIFICS:

In vitro test system

Test system:

artificial membrane barrier model

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKINTM (SM)
- Tissue batch number(s): Manufacturer: SkinEthic, France, Batch No.:17-EKIN-042, Expiry Date: 23 October 2017
- Production date:
- Shipping date:
- Delivery date:
- Date of initiation of testing:

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 26.2-26.8°C
- Temperature of post-treatment incubation (if applicable):

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps:
- Observable damage in the tissue due to washing:
- Modifications to validated SOP:

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration:
- Incubation time:
- Spectrophotometer:
- Wavelength:
- Filter:
- Filter bandwidth:
- Linear OD range of spectrophotometer:

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability:
- Barrier function:
- Morphology:
- Contamination:
- Reproducibility:

NUMBER OF REPLICATE TISSUES:

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- Fresh tissues / killed tissues
- Procedure used to prepare the killed tissues (if applicable):
- N. of replicates :
- Method of calculation used:

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

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if [complete, e.g. the viability after 3 minutes exposure is less than 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.]
- The test substance is considered to be non-corrosive to skin if [complete, e.g. the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.]
- Justification for the selection of the cut-off point(s) if different than recommended in TG 431 and 439:

Control samples:

yes, concurrent negative control

yes, concurrent positive control

yes, concurrent MTT non-specific colour control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 20 mg
- Concentration (if solution):

VEHICLE
- Amount(s) applied (volume or weight with unit): 10 µL distilled water
- Concentration (if solution):
- Lot/batch no. (if required):
- Purity:

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL
- Concentration (if solution):

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 5% w/v
- Concentration (if solution): 5% w/v

Duration of treatment / exposure:

15 m

Duration of post-treatment incubation (if applicable):

42 h

Number of replicates:

3

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

72.7

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

2

Value:

73.1

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3

Value:

80.1

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, in this in vitro EPISKIN TM (SM) model test with p-toluic acid (Batch number: 20170320), the results indicate that the test item is non-irritant to skin.