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Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in chemico
Type of information:
experimental study
Adequacy of study:
key study
Study period:
June - August 2018
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
Qualifier:
according to guideline
Guideline:
OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))
Version / remarks:
February 4, 2015
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
direct peptide reactivity assay (DPRA)

Test material

Constituent 1
Chemical structure
Reference substance name:
3-ethoxy-4-{[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}benzaldehyde
EC Number:
602-769-3
Cas Number:
122397-96-0
Molecular formula:
C15H20O8
IUPAC Name:
3-ethoxy-4-{[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}benzaldehyde
Test material form:
solid: particulate/powder

In chemico test system

Details on the study design:
In the present study Ethyl Vanillin Glucoside was dissolved in dist. water : acetonitrile 1:1 (v/v), based on the results of the pre-experiments.

Based on a molecular weight of 328 g/mol a 100 mM stock solution was prepared. 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.

For the 100 mM stock solution of the test item no turbidity or 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. Slight precipitation was observed for all the samples of the test item and for the samples of the positive control excluding the (co-elution control). Samples were not centrifuged prior to the HPLC analysis. The slight precipitation noted for the test item samples was also observed for reference controls, positive controls and standard solutions. It can be considered that it is related to the peptide and that it is not a precipitation of the test substance. Additionally, the precipitation did not change during the HPLC analysis period. As the stability of the cysteine peptide in the used acetonitrile batch was demonstrated successfully, the reactivity of the positive control towards the cysteine peptide and peptide depletion were identified correctly and the validity of the cysteine run was acceptable the precipitation was considered as not relevant.

For the 100 mM stock solution of the test item no turbidity or 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. Phase separation was observed for all the samples of the positive control including the co-elution control. No precipitation, turbidity or phase separation was observed for the samples of the test item. 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.
No co-elution of test item with the peptide peaks was observed. Sensitising potential of the test item was predicted from the mean peptide depletion of both analysed peptides (cysteine and lysine) by comparing the peptide concentration of the test item treated samples to the corresponding reference control.

Results and discussion

Positive control results:
Cinnamic aldehyde mean depletion of both petides 64.28%

In vitro / in chemico

Resultsopen allclose all
Key result
Run / experiment:
other: mean of 3 runs
Parameter:
other: cysteine depletion %
Value:
0
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
no indication of skin sensitisation
Key result
Run / experiment:
other: mean of 3 runs
Parameter:
other: peptide depletion %
Value:
13.51
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
positive indication of skin sensitisation
Key result
Run / experiment:
other: mean of 3 runs
Parameter:
other: cysteine and lysine depletion %
Remarks:
PM1
Value:
6.76
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
positive indication of skin sensitisation
Remarks:
low reactivity

Applicant's summary and conclusion

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Remarks:
minimal reactivity towards both peptides (PM1)
Conclusions:
In this study under the given conditions the test item showed minimal reactivity towards both peptides, however, due to the borderline depletion no prediction can be made.
Executive summary:

In this study under the given conditions the test item showed minimal reactivity towards both peptides, however, due to the borderline depletion no prediction can be made.