Octadecanoic acid, reaction products with triethylenetetramine, chloromethane-quaternized

Endpoint summary

Description of key information

The in chemico direct peptide reactivity assay (DPRA) enables detection of the sensitising potential of a test item by quantifying the reactivity of test chemicals towards synthetic peptides containing either lysine or cysteine. In this study the test item showed minimal reactivity towards both peptides. Due to the observed precipitation and the unknown concentration of the test item the prediction model does not apply and a prediction cannot be made.

 

The in vitro KeratinoSens™ assay enables detection of the sensitising potential of a test item by addressing the second molecular key event of the adverse outcome pathway (AOP), namely activation of keratinocytes, by quantifying the luciferase activity in the transgenic cell line KeratinoSens™. The luciferase activity, assessed by luminescence measurement, compared to the respective solvent controls is used to support discrimination between skin sensitisers and non-sensitisers. In this study under the given conditions the test item did not induce the luciferase activity in the transgenic KeratinoSens™ cell line in at least two independent experiment runs. Therefore, the test item can be considered as non-sensitiser.

 

The in vitro human cell line activation test (h-CLAT) enables detection of the sensitising potential of a test item by addressing the third molecular key event of the adverse outcome pathway (AOP), namely dendritic cell activation, by quantifying the expression of the cell surface markers CD54 and CD86 in the human monocytic cell line THP-1. The expression of the cell surface markers compared to the respective solvent controls is used to support discrimination between skin sensitisers and non-sensitisers. In this study under the given conditions the test item did upregulate the cell surface marker CD86 in at least two independent experiment runs. Therefore, the test item is considered to be a skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Details on the study design:

The in chemico direct peptide reactivity assay (DPRA) enables detection of the sensitising potential of a test item by quantifying the reactivity of test chemicals towards synthetic peptides containing either lysine or cysteine.

In the present study Octadecanoic acid, reaction product with triethylenetetramine, chloromethane-quaternized was dissolved in methanol, based on the results of the pre-experiments. Since no molecular weight could be derived the test item was tested to its maximum solubility, which was 45 mg/mL. The test item solutions were tested by incubating the samples with the peptides containing either cysteine or lysine for 24 ± 2 h at 25 ± 2.5 °C. Subsequently samples were analysed by HPLC analysis.

For the 45 mg/mL stock solution of the test item precipitation was observed when diluted with the cysteine peptide solution. After the 24 h ± 2 h incubation period but prior to the HPLC analysis samples were inspected for precipitation, turbidity or phase separation. Precipitation was observed for the samples of the test item (including the co-elution control). Samples were centrifuged prior to the HPLC analysis.

For the 45 mg/mL stock solution of the test item precipitation was observed when diluted with the lysine peptide solution. After the 24 h ± 2 h incubation period but prior to the HPLC analysis samples were inspected for precipitation, turbidity or phase separation. Precipitation was observed for the samples of the test item (including the co-elution control). Samples were centrifuged prior to the HPLC analysis. Phase separation was observed for the samples of the positive control (including the co-elution control). Samples were not centrifuged prior to the HPLC analysis.
Since the acceptance criteria for the depletion range of the positive control were fulfilled, the observed phase separation was regarded as not relevant.

Positive control results:

Cinnamic aldehyde ((2E)-3-phenylprop-2-enal)

Key result

Run / experiment:

other: HPLC determination of adducts between lysine-peptides and cisteine-peptides with the test substance.

Parameter:

other: Percentage depletion of peptides

Value:

0.31

Positive controls validity:

valid

Remarks on result:

not determinable

Remarks:

The solubility of the test substance was assayed with different solvents: - acetonitrile - dist. water - dist. water : acetonitrile 1:1 (v/v) - isopropanol - methanol - 1,4-butanediol - N,N-dimethylformamide - ethanol - tert. butanol The test item was not soluble at the highest concentration (100 mg/mL) in any of the tested solvents. However, as methanol seemed to be the best suited solvent tested, the concentration was lowered stepwise. At a concentration of 45 mg/mL the test item was completely soluble in methanol, therefore, methanol was chosen as suitable vehicle for the main experiments. The stock solution of the test item showed minimal reactivity towards the synthetic peptides. The mean depletion of both peptides was ≤ 6.38% (0.31%). Since precipitation was observed, the full contact of peptide and test item is not guaranteed. According to the evaluation criteria in the guideline, no firm conclusion on the lack of reactivity should be drawn from a negative result, if a test chemical is tested in concentration < 100 mM. Therefore, no prediction can be made.

Interpretation of results:

study cannot be used for classification

Conclusions:

In this study under the given conditions the test item showed minimal reactivity towards both peptides. Due to the observed precipitation and the unknown concentration of the test item the prediction model does not apply and a prediction cannot be made.

Reference 2

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From March 29 to July 26, 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD Guidelines for Testing of Chemicals, No. 442E: In Vitro Skin Sensitisation assays addressing the Key Event on activation of dendritic cells on the Adverse Outcome Pathway for Skin Sensitisation”, adopted 25 June 2018

Qualifier:

according to guideline

Guideline:

other: Human Cell Line Activation Test (h-CLAT) for Skin Sensitisation, DB-ALM Protocol n°158, July 1st, 2015

GLP compliance:

yes (incl. QA statement)

Type of study:

activation of dendritic cells

Specific details on test material used for the study:

Name: Octadecanoic acid, reaction product with triethylenetetramine, chloromethane-quaternized
Batch No.: I1-00001496126
CAS No.: 90459-71-5
Molecular Weight: not applicable (UVCB)
Storage Conditions: room temperature, protected from light
Expiry Date: 21 May 2019

Details on the study design:

Octadecanoic acid, reaction product with triethylenetetramine, chloromethane-quaternized was dissolved in 0.9% NaCl. For the dose finding assay stock solutions with concentrations ranging from 50 mg/mL to 0.39 mg/mL were prepared by a serial dilution of 1:2. Cells were incubated with the test item for 24 h at 37°C. After exposure cells were stained with propidium iodide and cell viability was measured by FACS analysis.

Run / experiment:

other: Second experiment

Parameter:

other: expression of the cell surface marker CD86

Value:

284

Negative controls validity:

valid

Positive controls validity:

valid

Run / experiment:

other: Third experiment

Parameter:

other: expression of the cell surface marker CD86

Value:

175

Negative controls validity:

valid

Positive controls validity:

valid

In all experiments no precipitation or turbidity of the test item was observed for all concentration steps when mixing the test item stock solutions with cell culture medium.

Cells were incubated with the test item for 24 h at 37°C. After exposure cells were stained and cell surface markers CD54 and CD86 were measured by FACS analysis. Cell viability was assessed in parallel using propidium iodide staining.

Slight cytotoxic effects were observed for the cells treated with the test item. Relative cell viability at the highest test item concentration was reduced to 89.2% (CD86), 89.6% (CD54) and 88.7% (isotype IgG1 control) in the first experiment, to 76.6% (CD86), 77.5% (CD54) and 97.1% (isotype IgG1 control) in the second experiment and to 84.4% (CD86), 81.1% (CD54) and 77.1% (isotype IgG1 control) in the third experiment.

In the first experiment the expression of cell surface marker CD86 and CD54 was not upregulated. The expression of the cell surface marker CD86 was upregulated up to 284% in the second experiment and up to 175% in the third experiment (24.53 µg/mL). The expression of the cell surface marker CD54 was upregulated up to 160% only in the second experiment (24.53 µg/mL).

Since the expression of the cell surface marker CD86 clearly exceeded the threshold in two independent experiments the test item is considered to be a skin sensitiser.

The controls confirmed the validity of the study for all experiments as shown inTable 8.

The data generated with this test should be considered in the context of integrated approached such as IATA, combining the result with other complementary information, e.g. derived from in vitro assays addressing other key events of the skin sensitisation AOP.

Since the expression of the cell surface marker CD86 clearly exceeded the threshold in two independent experiments the test item is considered to be a skin sensitiser.

Interpretation of results:

Category 1 (skin sensitising) based on GHS criteria

Conclusions:

In this study under the given conditions the test item did upregulate the cell surface marker CD86 in at least two independent experiment runs. Therefore, the test item is considered to be a skin sensitiser.

Reference 3

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test Method)

GLP compliance:

yes (incl. QA statement)

Type of study:

activation of keratinocytes

Details on the study design:

In the present study Octadecanoic acid, reaction product with triethylenetetramine, chloromethane-quaternized was dissolved in dist. water. As the test item had no defined molecular weight, the test was performed using a pro forma molecular weight of 200 g/mol. Based on this, a stock solution of 200 mM was prepared. It gave a stable suspension.

Based on the stock solution a set of twelve master solutions in 100% solvent was prepared by serial dilution:
400, 200, 100, 50, 25, 12.5, 6.25, 3.13, 1.56, 0.78, 0.39, 0.2 µM

The test was carried out using the transgenic cell line KeratinoSens™ , a cell line derived from human keratinocytes (HaCaT) transfected with a stable insertion of the Luciferase construct.

Cinnamic aldehyde was used as positive control, DMSO at a final concentration of 1% (v/v) in test item exposure medium was used as negative control.

After seeding cells were grown for 24 h ± 1 h in assay medium at 37 °C ± 1 °C and 5% CO2. Thereafter, the assay medium was discarded and replaced by test item exposure medium.
After 48 h ± 1 h of exposure, the supernatant was aspirated from the white assay plates and discarded. Cells were washed once with DPBS. Subsequently 20 µL of passive lysis buffer were added into each well and the plate was incubated for 20 min at room temperature in the absence of light.

Plates with the cell lysate were placed in the plate reader for luminescence measurement. Per well 50 µL of the luciferase substrate were injected by the injector of the plate reader. The plate reader waited for 1 sec. before assessing the luciferase activity for 2 sec.

For the cell viability plate the medium was replaced with 200 µL test item exposure medium. 27 µL MTT solution were added directly to each individual well. The plate was covered with a sealing tape and incubated for 4 h at 37 °C ± 1 °C and 5% CO2. Afterwards the medium was removed and replaced by 200 µL 10% SDS solution per well and incubated over the weekend (experiment 2) or for ten days (experiment 1) . After the incubation period the OD was measured at λ = 600 nm.

Run / experiment:

other: Experiment 2

Parameter:

other: luciferase induction

Value:

1.5

Negative controls validity:

valid

Positive controls validity:

valid

Run / experiment:

other: Experiment 1

Parameter:

other: luciferase induction

Value:

1.5

Negative controls validity:

valid

Positive controls validity:

valid

Interpretation of results:

study cannot be used for classification

Conclusions:

No dose response for luciferase activity induction was observed for each individual run as well as for an overall luciferase activity induction.

Under the condition of this study the test item is therefore considered as non-sensitiser.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to the integrated testing strategy adopted for the evaluation of the skin sensitization potential, the substance Octadecanoic acid, reaction products with triethylenetetramine, chloromethane-quaternized is considered as a skin sensitizer and therefore it is classified as Skin Sens 1, H317.