2,5-di-tert-butyl-p-benzoquinone

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Oct 2017-28 Feb 2018

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Justification for non-LLNA method:

The correlation of protein reactivity with skin sensitization potential is well established. Haptenation i.e. the covalent biding of low molecular weight substances (“Haptens”) to proteins present in skin is considered a prominent mechanism through which chemicals or their metabolites become antigenic. Therefore, information inferred from the DPRA assay is relevant for assessment for skin sensitization potential of chemicals.

Test material

Test material information

Constituent 1

Reference substance name:

2,5-di-tert-butyl-p-benzoquinone

EC Number:

219-552-0

EC Name:

2,5-di-tert-butyl-p-benzoquinone

Cas Number:

2460-77-7

Molecular formula:

C14H20O2

IUPAC Name:

2,5-di-tert-butyl-1,4-benzoquinone

Test material form:

solid: bulk

In chemico test system

Details on the study design:

Solutions of test item and positive control prepared at 100 mM concentration were used in the sample preparation for analysis. Test solution, positive control and reference control was added to cysteine and lysine peptides and incubated in dark at 25°C for 24±2 hours. The test samples were then loaded in HPLC auto sampler to measure the peptide depletion. The test samples were then analysed by reversed-phase HPLC coupled
with UV detector for detection of peptides at 220nm. The HPLC column Zorbax SBC18 (2.1mm X100mm X 3.5 micron) was equilibrated at 30°C with 50% phase A (0.1% (v/v) trifluoroacetic acid in water) and 50% phase B (0.085% (v/v) trifluoroacetic acid in acetonitrile). Analysis was carried out at a flow rate of 0.35 mL/min, with sample injection volume range of 10 μL. A linear gradient from 10% to 25% Acetonitrile over 10 minutes, was used for separation, followed by a rapid increase to 90% acetonitrile to remove other materials. Cysteine and lysine peptide Percent Depletion Values were then calculated from peptide peak areas obtained from the HPLC analysis.

Results and discussion

Positive control results:

Positive control cinnamaldehyde showed 71.03% and 35.59% mean cysteine and lysine peptide depletion.

In vitro / in chemico

Results

Results 1

Key result

Parameter:

other: cysteine peptide depletion %

Value:

19.56

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Key result

Parameter:

other: lysine peptide depletion %

Value:

0

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

2,5 Di Tertiary Butyl 1,4-Benzoquinone was concluded as positive with low reactivity in the skin sensitisation assay by Direct Peptide Reactivity Assay (DPRA)

Executive summary:

Skin sensitisation test by in chemico test method, Direct Peptide Reactivity Assay (DPRA) was carried out using the nucleophile containing synthetic cysteine and lysine peptides to evaluate the skin sensitisation potential of the test item 2,5-Di Tertiary Butyl 1,4-Benzoquinone (YAPOX2255) and classify them as skin sensitisers or non-skin sensitisers.

Cysteine and lysine peptide Percent Depletion Values are then calculated from peptide peak areas obtained from the HPLC analysis. The test item 2,5-Di Tertiary Butyl 1,4-Benzoquinone showed 19.56% mean cysteine peptide depletion and 0.0% mean lysine peptide depletion. Under the same circumstances positive control cinnamaldehyde showed 71.03% and 35.59% mean cysteine and lysine peptide depletion confirming the sensitivity of the assay. Based on the prediction model for classification Di Tertiary Butyl 1,4-Benzoquinone (YAPOX2255)] was concluded as positive with low reactivity in the skin sensitisation assay by Direct Peptide Reactivity Assay (DPRA).