Butane-1,2-diol

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 June – 27 June 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 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of study:

direct peptide reactivity assay (DPRA)

Test material

Test material information

Constituent 1

Reference substance name:

Butane-1,2-diol

EC Number:

209-527-2

EC Name:

Butane-1,2-diol

Cas Number:

584-03-2

Molecular formula:

C4H10O2

IUPAC Name:

butane-1,2-diol

In chemico test system

Details on the study design:

PEPTIDE AND POSITIVE CONTROLS :
Synthetic peptide containing Cysteine: Ac-RFAACAA-COOH
Synthetic peptide containing Lysine: Ac-RFAAKAA-COOH
Positive control: Cinnamic Aldehyde

ANALYTICAL PROCEDURE:
- Preparation of the peptides:
Stock solutions of each peptide at concentrations of 0.667 mM were prepared by dissolution of pre-weighed aliquots of the appropriate peptide in ca 20 mL aliquots of the appropriate buffer solution (Cysteine in 100 mM phosphate buffer pH 7.5, Lysine in 100 mM Ammonium acetate buffer pH 10.2).

- Preparation of the test material:
The solubility of 1,2-butanediol in acetonitrile was assessed at a concentration of 100 mM.
Acetonitrile solutions of 1,2-butanediol were diluted with the Cysteine peptide to prepare solutions (in triplicate for each) containing 0.5 mM Cysteine and 5 mM of 1,2-butanediol.
Acetonitrile solutions of 1,2-butanediol were diluted with the Lysine peptide to prepare solutions (in triplicate for each) containing 0.5 mM Lysine and 25 mM of 1,2-butanediol.

- Preparation of positive control:
Cinnamic aldehyde was prepared at a concentration of 100 mM in acetonitrile.
Cinnamic aldehyde were diluted with the Cysteine peptide to prepare solutions (in triplicate for each) containing 0.5 mM Cysteine and 5 mM of Cinnamic aldehyde.
Cinnamic aldehyde were diluted with the Lysine peptide to prepare solutions (in triplicate for each) containing 0.5 mM Lysine and 25 mM of Cinnamic aldehyde.

INCUBATION:
- Temperature: 25°C
- Duration: minimum 22 hours

ANALYSIS:
- Method: HLPC using UV detection
- Parameter measured: Peptide depletion was determined.
% Peptide depletion = 100 - (Peptide peak area in replicate depletion samples (x100)/ Mean Peptide peak area of reference control samples B)

ACCEPTANCE CRITERIA
Cysteine
- Linearity: > 0.99
- Positive control depletion: 60.8-100 (CV<14.9%)
- Reference controls: 0.45-0.55 mM (CV<15%)
- Test item: CV<14.9%
Lysine
- Linearity: > 0.99
- Positive control depletion: 40.2-69.0 (CV<11.6%)
- Reference controls: 0.45-0.55 mM (CV<15%)
- Test item: CV<11.6%
CV: coefficient of variation

Results and discussion

Positive control results:

All analytical acceptance criteria for each peptide run were met.

In vitro / in chemico

Results

Results 1

Key result

Run / experiment:

other: Cysteine

Parameter:

other: Mean peptide depletion (%)

Value:

0.493

Vehicle controls validity:

other: Reference controls valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Results 2

Key result

Run / experiment:

other: Lysine

Parameter:

other: Mean peptide depletion (%)

Value:

-2.16

Vehicle controls validity:

other: Reference controls valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Other effects / acceptance of results:

All analytical acceptance criteria for each peptide run were met.

Applicant's summary and conclusion

Interpretation of results:

other: no skin sensitising potential based on the key event “protein reactivity”

Conclusions:

There is regulatory acceptance in the EU for the application of the Direct peptide reactivity assay to address key event 1: peptide/protein binding in the skin sensitisation Adverse Outcome Pathway. Under the conditions of the test, the test substance did not show reactivity towards selected proteins. The result is not conclusive with respect to the non-classification or classification as skin sensitiser of the test substance and therefore further evaluation and/or data generation is required.