Ethanol, 2,2'-iminobis-, N-tallow alkyl derivs., N-oxides

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2018-07-03 to 2018-07-07

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

4 February 2015

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: DB-ALM (INVITTOX) Protocol 154: Direct Peptide Reactivity assay (DPRA) for skin sensitisation testing

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: SANCO Guideline 3030/99

Version / remarks:

rev.4, July 11, 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Test material

Test material information

Constituent 1

Reference substance name:

Ethanol, 2,2'-iminobis-, N-tallow alkyl derivs., N-oxides

EC Number:

263-179-6

EC Name:

Ethanol, 2,2'-iminobis-, N-tallow alkyl derivs., N-oxides

Cas Number:

61791-46-6

Molecular formula:

n.a

IUPAC Name:

Ethanol, 2,2'-iminobis-, N-tallow alkyl derivs., N-oxides

Test material form:

semi-solid (amorphous): gel

In chemico test system

Details on the study design:

The reactivity of a test chemical and synthetic cysteine or lysine containing peptides was evaluated by combining the test chemical with a solution of the peptide (reaction samples) and monitoring the remaining concentration of the peptide following 24 ± 2 hours of interaction time at room temperature (25 ± 2.5°C). The peptide is a custom material containing phenylalanine to aid in detection and either cysteine or lysine as the reactive centre. Relative concentrations of the peptide following the 24 hour reaction time were determined by HPLC with gradient elution and UV detection at 220 nm. Samples were prepared and analysed in triplicates in batches to keep the total HPLC analysis time less than 30 hours.

Results and discussion

Positive control results:

The positive control replicates (Cinnamaldehyde) showed the expected percent peptide depletion values within acceptable limits (68.53% with cysteine peptide and 51.63 % mean percent lysine peptide depletion).

In vitro / in chemico

Results

Key result

Parameter:

other: average peptide depletion of both peptides [%]

Value:

2.69

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

DEMONSTRATION OF TECHNICAL PROFICIENCY:
Prior to routine use of the method, TOXI-COOP ZRT. demonstrated technical proficiency in a separate study (Study number.: 392-442-2996) by correctly obtaining the expected DPRA prediction for 10 proficiency substances as recommended in the OECD TG 442C guideline.

ACCEPTANCE OF RESULTS: All acceptance citeria are fulfilled.
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes (cystein peptide depletion value of 68.53% (SD 2.03%) and a mean lysine peptide depletion of 51.63% (SD 2.35%))
- Acceptance criteria met for variability between replicate measurements: Yes (SD for the test chemical replicates was 7.14% for percent cysteine depletion and 0.85% for the percent lysine peptide depletion)

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Results obtained from this in chemico Direct Peptide Reactivity Assay with the test item Ethanol, 2,2’-iminobis-, N-tallow alkyl derivs., N-oxides indicated that the test item has no or minimal reactivity towards the synthetic peptides, thus is not a potential skin sensitizer.

Executive summary:

The skin sensitisation of the test item Ethanol, 2,2’-iminobis-, N-tallow alkyl derivs., N-oxides was evaluated according to OECD guideline 442C (Direct Peptide Reactivity Assay, DPRA).

At the beginning of the assay the solubility of the test chemical was assessed and acetonitrile was chosen as the appropriate solvent with which the test item formed a homogenous solution. Concentrations of the synthetic cysteine and lysine peptides following the 24 hours incubation time were determined by HPLC with gradient elution and UV detection at 220 nm.

Cysteine and lysine depletion values were to be used to categorize the test chemical in one of the four classes of reactivity. No co-elution was observed with either cysteine or lysine peptide, therefore the Cysteine 1:10 / Lysine 1:50 prediction model was used. The threshold of 6.38 % mean percent peptide depletion supported the discrimination between skin sensitisers and non-sensitisers in the framework of Integrated Approaches to Testing and Assesment (IATA).

The positive control replicates showed the expected percent peptide depletion values within acceptable limits (68.53% with cysteine peptide and 51.63 % mean percent lysine peptide depletion). The back-calculated values of the reference control replicates were within the expected molarity concentration range of 0.50 ± 0.05 mM. The experiment was considered to be valid.

The percent cysteine peptide depletion value of Ethanol, 2,2’-iminobis-, N-tallow alkyl derivs., N-oxides was 3.58 % while the percent lysine peptide depletion was 1.79 %. The Cysteine 1:10 / Lysine 1:50 prediction model was used for the discrimination between sensitisers and non-sensitisers based on the threshold of 6.38 %. The average percent peptide depletion value of the test item was 2.69 % which does not exceed the threshold. Results obtained from this in chemico Direct Peptide Reactivity Assay with the test item Ethanol, 2,2’-iminobis-, N-tallow alkyl derivs., N-oxides indicated that the test item has no or minimal reactivity towards the synthetic peptides, thus is not a potential skin sensitizer.