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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in chemico
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))
GLP compliance:
yes (incl. certificate)
Type of study:
not specified
Justification for non-LLNA method:
The study was performed in order to evaluate the reactivity of the test item Ginger, ext. towards cysteine (Cys-) and lysine (Lys-) containing peptides. The pure test item was in-cubated 24 ± 2 h at 25 °C together with cysteine and lysine peptides, respectively, and the peptide concentration after the incubation was measured using HPLC-UV.
Three replicates were prepared using 1:10 and 1:50 molar ratio of the test item with the Cys- and Lys-peptide, respectively. Triplicate samples of the solvent without test item were incubated and measured in parallel.
The peptide depletion values after incubation are shown in Table 3-a:

Test material

Reference
Name:
Unnamed

Results and discussion

In vitro / in chemico

Results
Parameter:
other: peptide concentration
Value:
> 6.38 - <= 100
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

Table8.3–a   Calculated peptide depletion values for the Lys-Peptide (Assay 1)

Sample name

Depletion [%]

Single

Mean

SD

Positive control Rep. 1

30.20

 

31.57

 

 

1.48

 

Positive control Rep. 2

31.39

Positive control Rep. 3

33.14

Test item Rep. 1

0.00

0.00

0.00

Test item Rep. 2

0.00

Test item Rep. 3

0.00

 

 

 

 

Table8.3–b  Calculated peptide depletion values for the Lys-Peptide (Assay 2)

Sample name

Depletion [%]

Single

Mean

SD

Positive control Rep. 1

33.60

 

36.24

 

 

2.91

 

Positive control Rep. 2

39.36

Positive control Rep. 3

35.75

Test item Rep. 1

0.00

0.00

0.00

Test item Rep. 2

0.00

Test item Rep. 3

0.00

 

Table8.3–c   Calculated peptide depletion values for the Cys-Peptide (Assay 1)

Sample name

Depletion [%]

Single

Mean

SD

Positive control Rep. 1

74.78

 

7.61

 

 

2.46

 

Positive control Rep. 2

78.77

Positive control Rep. 3

79.27

Test item Rep. 1

49.43

55.61

5.77

Test item Rep. 2

56.56

Test item Rep. 3

60.85

 

Table8.3–d  Calculated peptide depletion values for the Cys-Peptide (Assay 2)

Sample name

Depletion [%]

Single

Mean

SD

Positive control Rep. 1

77.73

 

79.69

 

 

1.71

 

Positive control Rep. 2

80.52

Positive control Rep. 3

80.83

Test item Rep. 1

48.71

56.19

8.18

Test item Rep. 2

54.93

Test item Rep. 3

64.93

 

 

Mean depletion of both peptides after incubation with the test item: 27.81 % (Assay 1) and 28.10 % (Assay 2)

 

1.1.1    Acceptance criteria

a)   The mean peptide depletion value for the positive control cinnamaldehyde should be 60.8 % - 100 % with a maximum standard deviation (SD) of < 14.9 % for the Cys-peptide.

b)   The mean peptide depletion value for the positive control 2,3-butanedione should be 10 % - 45 % with a maximum standard deviation < 11.6 % for the Lys-peptide.

c)   The maximum standard deviation for the test item replicates should be < 14.9 % for the percent cysteine depletion and < 11.6 % for the percent lysine depletion

1.1.2    Assessment

a)   The mean peptide depletion and standard deviation of the three replicates of the positive control cinnamaldehyde were in the acceptable range of 60.8 – 100.0 % and ≤ 14.9 %, respectively, for the Cys-peptide.

b)   The mean peptide depletion and standard deviation of the three replicates of the positive control 2,3-Butanedione were in the acceptable range of 10.0 – 45.0 % and ≤ 11.6 %, respectively, for the Lys-peptide.

c)   The maximum standard deviation for the test item replicates was < 14.9 % for the percent cysteine depletion for the test item.

The maximum standard deviation for the test item replicates was < 11.6 % for the percent lysine depletion for the test item.

1.2     Evaluation of results

According to the test guideline, the reactivity is classified as “high”, “moderate”, “low” or “minimal” using the Cysteine 1:10/Lysine 1:50 prediction model shown in Table8.4–a.

 

Table8.4–a   Evaluation of results according to the Cysteine 1:10/Lysine 1:50 prediction model

Mean peptide depletion
[%]

Reactivity Class

DPRA Prediction

0 – ≤ 6.38

Minimal

Negative

> 6.38 – ≤ 22.62

Low

Positive

> 22.62 – ≤ 42.47

Moderate

> 42.47 - ≤ 100

High

 

 

The mean peptide depletion in the Lys-peptide and Cys-peptide assay was 27.81 %, therefore the test had to be repeated for verification of this result. The mean peptide depletion in the Lys-peptide and Cys-peptide in the repeated experiment was 28.10 %. The result of the first experiment was considered verified:

 

DPRA Prediction: Positive

Reactivity class: Moderate

 

Applicant's summary and conclusion

Conclusions:
POSITIVE



All acceptance criteria were fulfilled, therefore the test was considered valid. The DPRA prediction for the test item Ginger, ext. was positive with reactivity class moderate accord-ing to the Cysteine 1:10/Lysine 1:50 prediction model. The result was verified in a second experiment.
No observations arousing doubts concerning the accuracy of the results and the validity of the study were made.