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Description of key information

In order to determine the skin sensitisation potential of Methylhydroquinone a Direct Peptide Reactivity assay (DPRA) was performed according to OECD TG 442C, In Chemico Skin Sensitisation.

Mean of percent Cysteine and percent Lysine depletion values is 88.45.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in chemico
Type of information:
experimental study
Adequacy of study:
key study
Study period:
12.3.2018 – 16.3.2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))
Version / remarks:
Adopted: 4 February 2015
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
direct peptide reactivity assay (DPRA)
Details on the study design:
A standard calibration curve was generated for both the Cysteine and the Lysine peptides.
Linearity was determined by mathematical treatment of results obtained by analysis of calibration solutions. These solutions were prepared from series dilution. The concentration interval of the calibration solutions was 0.534 – 0.01669 mM for each peptide.
Each prepared calibration solution was injected and analysed by HPLC with DAD detection.
Positive control results:
The mean percent peptide depletion value of three replicates for the positive control (Cinnamic aldehyd) should be between 60.8% - 100% for Cysteine peptide: 71.9%.
Key result
Run / experiment:
other: Replicate 1
Parameter:
other: Percent Cystein depletion %
Value:
99.9 %
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Key result
Run / experiment:
other: Replicate 2
Parameter:
other: Percent Cystein depletion %
Value:
99.9 %
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Key result
Run / experiment:
other: Replicate 3
Parameter:
other: Percent Cystein depletion %
Value:
99.9 %
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Key result
Run / experiment:
other: Replicate 1
Parameter:
other: Percent Lysine depletion %
Value:
75.6 %
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Key result
Run / experiment:
other: Replicate 2
Parameter:
other: Percent Lysine depletion %
Value:
78.6 %
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Key result
Run / experiment:
other: Replicate 3
Parameter:
other: Percent Lysine depletion %
Value:
76.9 %
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Other effects / acceptance of results:
All study acceptance criteria have been successfully met.

Determining the reactivity class and the DPRA prediction for Methylhydroquinone

Test item 

CAS No.:

Mean of Percent Cystein depletion %

Mean of Percent Lysine depletion %

Mean of Cystein and Lysine Percent depletion %

Reactivity Class

DPRA prediction

Methylhydroquinone

95-71-6

99.9

77.0

88.45

High reactivity

Positive

 

Mean of percent Cysteine and percent Lysine depletion values is 88.45.Test item Methylhydroquinone was included in the reactivity class – high reactivity and was classified as positive (skin sensitizer) in DPRA prediction.

Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Conclusions:
Methylhydroquinone was classified as positive (skin sensitizer) in the DPRA (OECD Test 442C: In Chemico Skin Sensitisation). It was assigned to reactivity class: high reactivity.
Executive summary:

In order to determine the skin sensitisation potential of Methylhydroquinone a Direct Peptide Reactivity assay (DPRA) was performed according to OECD TG 442C, In Chemico Skin Sensitisation.

Mean of percent Cysteine and percent Lysine depletion values is 88.45. Based on the results obtained, the Cysteine 1:10/Lysine 1:50 prediction model was used.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Methylhydroquinone was classified as positive (skin sensitizer) in the DPRA (OECD Test 442C: In Chemico Skin Sensitisation). It was assigned to reactivity class: high reactivity.