Registration Dossier

Administrative data

Description of key information

Skin sensitisation (OECD 442E): sensitising

Skin sensitisation (OECD 442C): not sensitising

Skin sensitisation (OECD 442D): no prediction can be made

Skin sensitisation (OECD 442B): sensitising

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Referenceopen allclose all

Endpoint:
skin sensitisation: in vitro
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
13 June - 01 July 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
/ cytotoxicity measurement and estimation of the CV75 value of the dose finding assay was performed by XTT test instead of flow cytometry, no demonstration of technical proficiency in the report
Qualifier:
according to
Guideline:
other: OECD Guideline 442E (In Vitro Skin Sensitisation: human Cell Line Activation Test)
Version / remarks:
29 July 2016
Deviations:
yes
Remarks:
/ cytotoxicity measurement and estimation of the CV75 value of the dose finding assay was performed by XTT test instead of flow cytometry, no demonstration of technical proficiency in the report
GLP compliance:
yes (incl. certificate)
Remarks:
Hess. Ministerium für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany
Type of study:
activation of dendritic cells
Details on study design:
TEST CELL LINE
- Source: American Type Culture Collection (ATCC)
- Passage number: 4 (XTT test); 10 + 11 (h-CLAT)

CELL CULTURE CONDITIONS
- Type and identity of media: RPMI-1640 supplemented with 10% (v/v) FBS, 100 U/mL penicillin, 100 µg/mL streptomycin, 0.05 mM 2-mercaptoethanol, 4.5 g/L glucose, 1% (v/v) sodium pyruvate and 1% (v/v) L-glutamine
- Temperature (°C): 37 ± 1.5
- CO2 (%): 5.0 ± 0.5

INFORMATION FOLLOWING IN THE NEXT 9 PARAGRAPHS RELATE TO DETAILS ON XTT:

The XTT test is a method to investigate the cytotoxicity of a test substance. The test is based on the cleavage of the yellow tetrazolium salt, sodium 3'-(1-phenylaminocarbonyl)-(3,4 - tetrazolium)-bis-(4–methoxy-6-nitro)-benzenesulfonic acid hydrate (XTT), to form an orange water soluble formazan dye by dehydrogenase activity in active mitochondria. Two independent cytotoxicity experiments were performed with different cell cultures and on different days to obtain a reliable concentration showing 75% cell viability (CV75).

CONTROLS
Negative Control
- Substance: culture medium
Vehicle control
- Substance: dimethyl sulfoxide (DMSO)
- Concentration: 0.2 - 0.5%

EXPOSURE CONDITIONS
- Exposure duration: 24 ± 1 h

TEST CONCENTRATIONS
- Justification for top dose: The test substance was soluble in DMSO up to and including 125 µg/mL.
0.975, 1.95, 3.91, 7.81, 15.63, 31.25, 62.5 and 125 µg/mL

NUMBER OF REPLICATIONS: 4 samples per dose group were tested in two independent experiments

MEASUREMENT
- Device: microplate reader (Versamax, Molecular Devices)
- Wavelength: 450 nm
- Reference wavelength: 690 nm

EVALUATION CRITERIA
A decrease in number of living cells results in a decrease in the overall activity of mitochondrial dehydrogenases in the sample. This decrease directly correlates to the amount of orange formazan formed, as monitored by the absorbance. The relative absorbance as compared to the solvent control is calculated using the formula:
Relative absorbance = 100 x [(mean absorbance test substance) - (absorbance blank)] / [(mean absorbance vehicle control) - (absorbance blank)]

To calculate the concentration of test substance needed to reduce the relative absorbance to 75% of the vehicle control (CV75) the following formula is used:
CV75 = Conc. > 75 - ([(Conc. > 75) - (Conc. < 75)] x [(% > 75) - 75] / [(% > 75) - (% < 75)])
a) Conc. > 75: max. measured concentration with the % of vehicle control > 75%
b) Conc. < 75: min. measured concentration with the % of vehicle control < 75%
c) % > 75: relative absorbance at a) in %
d) % < 75: relative absorbance at b) in %

ACCEPTANCE CRITERIA
The XTT test is considered to be acceptable if it meets the following criteria:
- mean absorbance of the negative control is ≥ 0.5
- mean viability of the vehicle control is ≥ 70%


INFORMATION FOLLOWING IN THE NEXT PARAGRAPHS RELATE TO DETAILS ON H-CLAT:

The h-CLAT method is an in vitro method which quantifies changes of cell surface marker expression (CD86 and CD54) on a human cell line, THP-1 cells, following 24 h exposure to the test substance. The changes of surface marker expression are measured by flow cytometry following cell staining with fluorescein isothiocyanate (FITC)-labelled antibodies. The relative fluorescence intensity of surface markers compared to solvent control are calculated and used in the prediction model to support the discrimination between sensitisers and non-sensitisers.

CONTROLS
Negative Control
- Substance: culture medium
Vehicle control
- Substance: DMSO
- Concentration: 0.2%
Positive control
- Substance: 2,4-dinitrochlorobenzene in DMSO
- Concentration: 2 and 3 µg/mL

EXPOSURE CONDITIONS
- Exposure duration: 24 ± 1 h

TEST CONCENTRATIONS
- Justification for top dose: The highest concentration should have been 1.2 × highest soluble test item concentration (125 μg/mL), i.e. 150 μg/mL. However, due to a calculation error, the highest test substance concentration used was 300 μg/mL instead of 150 μg/mL.
83.7, 100.5, 120.6, 144.7, 173.6, 208.3, 250 and 300 μg/mL

NUMBER OF REPLICATIONS: at least in triplicates for the different stainings in two independent experiments

STAINING
- Antibodies: FITC anti-CD54 (Clone: Fun-1); FITC anti-CD86 (Clone: 6.5B5); FITC mouse IgG1 (isotype control)
- Temperature: 2 - 8 °C (on ice)
- Duration: 30 ± 5 min

MEASUREMENT
- Device: FACSCalibur (Becton Dickinson)

EVALUATION CRITERIA
The relative fluorescence intensity (RFI) is used as an indicator of CD86 and CD54 expression, and is calculated for each concentration as follows:
RFI (%) = [(MFI of test substance treated cells) - (MFI of test substance isotype control cells) / (MFI of vehicle control cells) - (MFI of vehicle isotype control cells)] x 100
MFI: geometric mean fluorescence intensity (GeoMean)

The cell viability is calculated as follows for each concentration:
Cell viability (%) = (mean cytotox of vehicle control cells) / (mean cytotox of test substance treated cells) x 100
Where the mean cytotox is the mean of GeoMean (7-AAD) isotype control, GeoMean (7-AAD) CD54 and GeoMean (7-AAD) CD86.

The test substance is tested in 2 independent runs. If the RFI of CD86 is ≥ 150% or if the RFI of CD54 is ≥ 200% in both independent run data, the test substance is considered to be a sensitizer. Otherwise it is considered to be a non-sensitizer. In case of different results in both runs, a third run has to be performed. If the RFI of CD86 is ≥ 150% at any dose in at least 2 of 3 independent run data, or if the RFI of CD54 is ≥ 200% in at least 2 of 3 independent run data, the test substance is considered to be a sensitizer. Otherwise it is considered to be a non-sensitizer.

ACCEPTANCE CRITERIA
The study is considered as valid, if the following criteria are met:
- Cell viability of negative control is adjusted to 100% and the cell viability of the vehicle control should be more than 90% in comparison to the negative control.
- In the positive control, RFI values of both CD86 and CD54 should exceed the positive criteria (CD86 ≥ 150% and CD54 ≥ 200%) and the cell viability should be > 50%.
- In the vehicle control, RFI values compared to the negative control of both CD86 and CD54 should not exceed the positive criteria (CD86 ≥ 150% and CD54 ≥ 200%).
- For negative and vehicle controls, the MFI ratio of CD86 and CD54 to isotype control should be > 105%.
- For the test substance resulting in negative outcome, the cell viability at the 1.2 × CV75 value should be less than 90%. If the cell viability at the 1.2 × CV75 value is more than 90% for a positive tested test substance, the data will be acceptable. If 5 mg/mL in saline, 1 mg/mL in DMSO or the highest soluble dose will be used as the maximal test concentration instead of CV75-based dose, the data for test substance are accepted independent by the cell viability.
- The cell viability of at least 4 doses in each experiment should be ≥50%.
Key result
Parameter:
other: relative fluorescence intensity (RFI) of CD54 (%)
Run / experiment:
24 h incubation
Value:
> 200
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: exceeding positive criteria, except of at 100.5 μg/mL in exp.1 and from 83.7 to 144.7 μg/mL in exp.2 (< 200%)
Key result
Parameter:
other: relative fluorescence intensity (RFI) of CD86 (%)
Run / experiment:
24 h incubation
Value:
< 150
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: only in exp.1 at 300 μg/mL an RFI of > 150% (exceeding positive criteria) was observed
Other effects / acceptance of results:
ADDITIONAL INFORMATION ON CYTOTOXICITY:
XTT test
No cytotoxic effects (i.e. cell viability less than 50%) were observed following incubation with the tested concentrations.

DEMONSTRATION OF TECHNICAL PROFICIENCY: no information provided

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for vehicle control: In the vehicle control, RFI values compared to the negative control of both CD86 and CD54 did not exceed the positive criteria (CD86 ≥150% and CD54 ≥ 200%).
- Acceptance criteria met for positive control: The RFI values of the positive control for CD86 and CD54 exceeded the positive criteria (CD86 >150% and CD54 >200%) and the cell viability was >50%.

Table 1: Results of the first XTT test

 

Concentration [µg/mL]

Mean absorbance*

Blank

Absorbance in % of vehicle control**

Negative control

-

0.806 ± 0.019

0.223

97.03

Vehicle control

-

0.870 ± 0.018

0.268

100.0

Test item

0.98

0.798 ± 0.033

0.265

88.72

1.95

0.785 ± 0.021

0.271

85.33

3.91

0.774 ± 0.021

0.267

84.19

7.81

0.728 ± 0.036

0.274

75.43

15.63

0.782 ± 0.034

0.273

84.59

31.25

0.809 ± 0.028

0.278

88.41

62.5

0.810 ± 0.040

0.280

87.95

125

0.828 ± 0.052

0.293

88.85

*: mean absorbance (absolute) of 4 wells

**: relative absorbance

 

Table 2: Results of the second XTT test

 

Concentration [µg/mL]

Mean absorbance*

Blank

Absorbance in % of vehicle control**

Negative control

-

0.733 ± 0.006

0.261

96.29

Vehicle control

-

0.758 ± 0.027

0.268

100.0

Test item

0.98

0.728 ± 0.026

0.254

96.65

1.95

0.738 ± 0.010

0.253

98.88

3.91

0.741 ± 0.018

0.255

98.88

7.81

0.735 ± 0.012

0.253

98.35

15.63

0.742 ± 0.019

0.264

97.33

31.25

0.767 ± 0.006

0.262

102.91

62.5

0.814 ± 0.035

0.262

112.48

125

0.823 ± 0.040

0.268

113.05

*: mean absorbance (absolute) of 4 wells

**: relative absorbance

 

Table 3. Results of the first h-CLAT run

 

Concentration [µg/mL]

Antibody / ISO

MFI

GeoMean (FITC)

MFI - ISO

Cyto(Geo) GeoMean

(7-AAD)

Mean Cyto

RFI (%)

Viability (%)

Negative control

-

ISO

2.51

-

2.35

2.1

-

100.0

CD54

3.16

0.65

2.00

100.0

CD86

4.37

1.86

1.94

100.0

Vehicle control

-

ISO

2.35

-

2.26

2.0

-

100.0

CD54

3.17

0.82

2.06

100.0

CD86

4.32

1.97

1.82

100.0

Positive control

(DNCB)

2

ISO

2.73

-

2.61

2.0

-

104.6

CD54

9.45

6.72

1.74

819.5*

CD86

12.57

9.84

1.52

499.5*

3

ISO

2.67

-

2.88

2.1

-

98.7

CD54

11.36

8.69

1.77

1059.8*

CD86

13.66

10.99

1.57

557.9*

Test item

83.7

ISO

2.74

-

1.38

2.1

-

97.9

CD54

4.70

1.96

1.93

239.0*

CD86

4.75

2.01

1.96

102.0

100.5

ISO

2.71

-

2.34

2.1

-

99.8

CD54

4.16

1.45

2.00

176.8

CD86

5.21

2.50

1.81

126.9

120.6

ISO

2.75

-

2.35

2.1

-

98.6

CD54

4.43

1.68

1.99

204.9*

CD86

4.85

2.10

1.89

106.6

144.7

ISO

2.90

-

2.53

2.2

-

92.3

CD54

5.09

2.19

2.10

267.1*

CD86

5.52

2.62

2.02

133.0

173.6

ISO

2.92

-

2.83

2.4

-

84.8

CD54

4.90

1.98

2.26

241.5*

CD86

5.35

2.43

2.15

123.4

208.3

ISO

3.01

-

2.76

2.4

-

85.5

CD54

5.07

2.06

2.30

251.2*

CD86

5.79

2.78

2.12

141.1

250

ISO

3.03

-

2.95

2.5

-

81.9

CD54

5.33

2.30

2.34

280.5*

CD86

5.77

2.74

2.21

139.1

300

ISO

3.41

-

4.20

3.6

-

57.5

CD54

6.50

3.09

3.35

376.8*

CD86

7.57

4.16

3.13

211.2*

  *: RFI value of CD86 or CD54 exceeded the criteria for a positive response (CD86 ≥ 150% and CD54 ≥ 200%).

DNCB = 2,4-dinitrochlorobenzene

Table 4. Results of the second h-CLAT run

 

Concentration [µg/mL]

Antibody / ISO

MFI GeoMean (FITC)

MFI - ISO

Csto(Geo) GeoMean (7-AAD)

Mean Cyto

RFI (%)

Viability (%)

Negative control

-

ISO

2.28

-

2.35

2.2

-

100

CD54

2.94

0.66

2.19

100

CD86

3.86

1.58

1.98

100

Vehicle control

-

ISO

2.22

-

2.39

2.1

-

100

CD54

2.96

0.74

2.24

100

CD86

4.09

1.87

1.52

100

Positive control

2

ISO

2.42

-

2.78

2.4

-

87.2

CD54

7.23

4.81

2.29

650.0*

CD86

6.42

4.00

1.98

213.9*

3

ISO

2.61

-

3.25

2.3

-

89.8

CD54

8.83

6.22

1.83

840.5*

CD86

9.39

6.78

1.77

362.6*

Test substance

83.7

ISO

2.55

-

2.71

2.3

-

88.6

CD54

3.68

1.13

2.23

152.7

CD86

4.31

1.76

2.00

94.1

100.5

ISO

2.54

-

2.48

2.2

-

93.5

CD54

3.82

1.28

2.16

173.0

CD86

4.54

2.00

1.94

107.0

120.6

ISO

2.60

-

2.52

2.2

-

94.8

CD54

3.97

1.37

2.18

185.1

CD86

5.10

2.50

1.79

133.7

144.7

ISO

2.60

-

2.67

2.3

-

87.7

CD54

3.99

1.39

2.25

187.8

CD86

4.20

1.60

2.09

85.6

173.6

ISO

2.61

-

2.76

2.4

-

84.6

CD54

4.29

1.68

2.33

227.0*

CD86

4.56

1.95

2.18

104.3

208.3

ISO

2.72

-

2.95

2.5

-

80.5

CD54

4.87

2.15

2.42

290.5*

CD86

5.00

2.28

2.27

121.9

250

ISO

2.81

-

2.99

2.6

-

78.6

CD54

4.98

2.17

2.53

293.2*

CD86

5.48

2.67

2.30

142.8

300

ISO

3.01

-

3.23

2.8

-

74.1

CD54

5.18

2.17

2.63

293.2*

CD86

5.80

2.79

2.44

149.2

  *: RFI value of CD86 or CD54 exceeded the criteria for a positive response (CD86 ≥ 150% and CD54 ≥ 200%).

DNCB =2,4-dinitrochlorobenzene

In the first run the relative fluorescence intensity of CD86 exceeded the threshold of 150% in the cells treated with test item concentration of 300 μg/mL. In the second run the relative fluorescence intensity of CD86 did not exceed the threshold at the test item concentrations tested.

In the first run the relative fluorescence intensity of CD54 exceeded the threshold of 200% in the cells treated with test item concentration of 83.7 μg/mL and between 120.6 and 300 μg/mL. In the second run the relative fluorescence intensity of CD54 exceeded the threshold in cells treated with the test item concentration between 173.6 and 300 μg/mL. Even if higher test item concentrations were used in the main experiment as recommended according to the guideline, the result is considered to be valid and acceptable since the cell viability at this test substance concentration did not fall below 50% cell viability.

Interpretation of results:
other: skin sensitising potential based on the key event “activation of dendritic cells”
Conclusions:
Under the conditions of the test, the test substance induces dendritic cell activation. The result does not allow for the non-classification or classification as skin sensitiser of the test substance and therefore further evaluation and/or data generation is required.
Executive summary:

In the Human Cell Line Activation Test (h-CLAT) (OECD 442E) (2016),THP-1cells were treated for 24 h with concentrations ranging from83.7 to 300 μg/mL, resulting in a relative fluorescence intensity (RFI) of CD54 >200% (at 83.7 μg/mL and between 120.6 and 300 μg/mL in exp. 1 and at 173.6 and 300 μg/mL in exp. 2) and of CD86 < 150% (at all concentrations in both exp., except at 300 μg/mL in exp. 1).

Based on this result, the h-CLAT prediction is considered positive for skin sensitisation.

Endpoint:
skin sensitisation: in chemico
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
27 June - 14 July 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
/ no information on co-elution control and reference controls provided, no demonstration of technical proficiency in the report
Qualifier:
according to
Guideline:
OECD Guideline 442C (In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA))
Version / remarks:
04 Feb 2015
Deviations:
yes
Remarks:
/ no information on co-elution control and reference controls provided, no demonstration of technical proficiency in the report
GLP compliance:
yes (incl. certificate)
Remarks:
THE DEPARTMENT OF HEALTH OF THE GOVERNMENT OF THE UNITED KINGDOM, UK
Type of study:
direct peptide binding assay
Details on study design:
TEST SYSTEM
- Supplier: AnaSpec
- Cysteine-containing peptide:
Alternative name: Ac-RFAACAA-OH
Batch number: 1556171
Molecular weight: 751.5 g/mol
Purity: 95%
Expiry date: 5 years
- Lysine-containing peptide:
Alternative name: Ac-RFAAKAA-OH
Batch number: 1556172
Molecular weight: 776 g/mol
Purity: 90 - 95%
Expiry date: 5 years

TEST METHOD
The DPRA is an in chemico test system proposed to address the molecular initiating event of the skin sensitisation adverse outcome pathway, namely protein reactivity, by substance towards model synthetic peptides containing either lysine or cysteine. The DPRA quantifies the free concentration of cysteine- or lysine-containing peptide following incubation with the test substance. Relative peptide concentration is measured by HPLC with gradient elution and UV detection at 220 nm. Cysteine- and lysine peptide percent depletion values are then calculated and used in the prediction model which allows assigning the test substance to one of four reactivity classes used to support the discrimination between sensitisers and non-sensitisers.

POSITIVE CONTROL
- Substance: cinnamic aldehyde
- Supplier: SAFC
- Batch number: MKBR2427V
- Purity: >95%
- Expiry date: Feb 2019

STABILITY AND PRECISION CONTROL
Stability and precision controls of both peptides were prepared at a concentration of 0.5 mM.

POSITIVE CONTROL PREPARATION
The positive control was prepared at a concentration of 100 mM.

TEST SUBSTANCE PREPARATION
The test substance was prepared as a 100 mM preparation in acetonitrile.

PEPTIDE STOCK SOLUTION PREPARATION
Cysteine-containing peptide:
- Solvent: phosphate buffer (pH 7.5)
- Concentration: 0.667 mM
Lysine-containing peptide:
- Solvent: ammonium acetate buffer (pH 10.2)
- Concentration: 0.667 mM

INCUBATION CONDITIONS
- Peptide solutions: Cysteine-containing peptide: 0.5 mM peptide and 5 mM test item/ positive control; Lysine-containing peptide: 0.5 mM peptide, 25 mM test item/ positive control
- Temperature used during treatment / exposure: 25 °C
- Duration of treatment / exposure: at least 22 h

NUMBER OF REPLICATES
triplicates, for each peptide for treatment and positive control

HIGH PERFORMANCE LIQUID CHROMATOGRAPHY
- Specification of the device: Waters Alliance 2695 separation module and 2487 dual wavelength detector
- Column: Agilent Zorbax SB C18, 3.5 µm, 100 x 2.1 mm with guard column Phenomenex AJO4286
- HPLC mobile phase:
A: 0.1% (v/v) trifluoracetic acid in water
B: 0.085% (v/v) trifluoracetic acid in acetonitrile
- Flow: 0.35 mL/min
- Gradient:
Time (min): 0, 20, 21, 23, 23.5, 30
% A: 90, 75, 10, 10, 90, 90
% B: 10, 25, 90, 90, 10, 10
- Wavelength: 220 nm, UV
- Injection volume: 2 µL
- Column temperature: 30 °C
Key result
Parameter:
other: % depletion of cysteine-containing peptide
Remarks:
(mean value of 3 replicates)
Run / experiment:
≥ 22 h incubation
Value:
6.45
Vehicle controls validity:
not specified
Negative controls validity:
not specified
Positive controls validity:
valid
Key result
Parameter:
other: % depletion of lysine-containing peptide
Remarks:
(mean value of 3 replicates)
Run / experiment:
≥ 22 h incubation
Value:
-0.95
Vehicle controls validity:
not specified
Negative controls validity:
not specified
Positive controls validity:
valid
Key result
Parameter:
other: mean of cysteine and lysine % depletion
Run / experiment:
≥ 22 h incubation
Value:
3.23
Vehicle controls validity:
not specified
Negative controls validity:
not specified
Positive controls validity:
valid
Other effects / acceptance of results:
TEST-SPECIFIC CONFOUNDING FACTORS
The solubility of the test item in acetonitrile at a nominal concentration of 100 mM was confirmed.

DEMONSTRATION OF TECHNICAL PROFICIENCY: no information provided

ACCEPTANCE OF RESULTS:
All analytical acceptance criteria for each peptide were met.
- Acceptance criteria met for negative control: The measured values of the reference control (0.527 and 0.497 mM for cystein and lysine, respectively) were in the range of the acceptance criteria (0.45 - 0.55 mM for cystein and lysine)
- Acceptance criteria met for positive control: The measured depletion values of the positive control (69.7 and 58.4% for cystein and lysine, respectively) were in the range of the acceptance criteria (60.8 - 100% and 40.2 - 69.0% for cystein and lysine, respectively)
- Acceptance criteria met for variability between replicate measurements: The Coefficients of Variation (CV) of 2.79 and 0.37% for cystein and lysine, respectively, met the acceptance criteria (< 14.9 and 11.6% for cystein and lysine, respectively).

Table 5: Mean peptide depletion of cysteine-containing peptide.

 

Peak area (µV.sec)

Peptide concentration [µg/mL)*

Peptide depletion (%)**

Mean depletion ± CV (%)

Test item

916327

382.22

3.47

6.45 ± 2.79

870350

362.52

8.31

877331

365.51

7.58

Positive control

279682

109.54

70.5

69.7 ± 2.41

291615

114.65

69.3

291759

114.72

69.3

 *: Samples prepared at a concentration of 376 μg/mL (0.5 mM)

**: Calculated against a mean reference control peak area of 949240 μV.sec (n=6)

Table 6: Mean peptide depletion of lysine-containing peptide.

 

Peak area (µV.sec)

Peptide concentration [µg/mL)*

Peptide depletion (%)**

Mean depletion ± CV (%)

Test item

790895

395.23

-1.37

-0.95 ± 0.37

786470

393.01

-0.81

785498

392.52

-0.68

Positive control

314190

156.37

59.7

58.4 ± 3.22

324364

161.47

58.4

335094

166.84

57.0

*: Samples prepared at a concentration of 388 μg/mL (0.5 mM)

**: Calculated against a mean reference control peak area of 780180 μV.sec (n=6)

Table 7: Overall mean of cysteine and lysine peptide depletion

 

Cysteine

peptide depletion (%)

Lysine peptide
depletion (%)

Overall mean
depletion (%)

Reactivity class

DPRA result

Test item

6.45

0.00*

3.23

no or minimal reactivitity

negative

*Actual value: -0.95%

Interpretation of results:
other: No skin sensitising potential based on the key event “protein reactivity”
Conclusions:
Under the conditions of the test, the test substance did not show reactivity or only minimal activity towards selected proteins.
Executive summary:

In the In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA) (OECD 442C) (2017),model synthetic peptides containing either lysine or cysteine were incubated for at least 22 h with 25 mM and 5 mM, respectively. The mean depletion ofcysteine-containing peptides was 6.45%, while the mean peptide depletion of lysine-containing peptides was -0.95, resulting in an overall mean of cysteine and lysine peptide depletion of 3.23% and therefore a negative outcome of the test (threshold for a positive result was > 6.38%).

Based on this result, the DPRA showed no or minimal peptide reactivity of the test substance.

Endpoint:
skin sensitisation: in vitro
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
21 Nov - 02 Dec 2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test Method)
Version / remarks:
adopted 04 February 2015
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
GLP-Landesleitstelle Bayern, Bayrisches Landesamt für Gesundheit und Lebensmittelsicherheit, Schwabach, Germany
Type of study:
activation of keratinocytes
Details on study design:
TEST METHOD
The in vitro KeratinoSens™ assay enables detection of the sensitising potential of a test substance 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 sensitiser and non-sensitisers.

TEST CELL LINE
- Type: KeratinoSens™
- Source: Givaudan, Switzerland
- Passage number: 05 (exp. 1), 06 (exp. 2)

CELL CULTURE CONDITIONS
- Type and identity of media:
Maintenance medium: Dulbecco’s Modified Eagle Medium (GlutaMAX TM) supplemented with 1.0 g/L D-glucose and Na-pyruvate, 10% fetal bovine calf serum and 1% geneticin (final concentration 500 µg/mL)
Assay medium: Dulbecco’s Modified Eagle Medium (GlutaMAX TM) supplemented with 1.0 g/L D-glucose and Na-pyruvate and 10% fetal bovine calf serum
Test item exposure medium: Dulbecco’s Modified Eagle Medium (GlutaMAX TM) supplemented with 1.0 g/L D-glucose and Na-pyruvate and 1% fetal bovine calf serum
- Temperature (°C): 37 ± 1.0
- CO2 (%): 5.0

TEST CONCENTRATIONS
0.98, 1.95, 3.91, 7.81, 15.63, 31.25, 62.5, 125, 250, 500, 1000 and 2000 µM

CONTROLS
Vehicle control
- Substance: dimethyl sulfoxide (DMSO)
- Final concentration: 1%
Positive control
- Substance: cinnamic aldehyde
- Final concentration: 4 - 64 µM

EXPOSURE CONDITIONS
- Exposure duration: 48 ± 1 h

NUMBER OF REPLICATIONS: two independent exp. with 3 replicates (test item and positive control group) and 6 replicates (vehicle control group)

DETERMINATION OF CELL VIABILITY
- Method: MTT assay
- MTT concentration: 5 mg/mL (stock solution)
- Incubation time: 4 h at 37 °C
- Device: plate reader
- Wavelength: 600 nm

DETERMINATION OF LUMINESCENCE
- Luciferase reagent: Luciferase Assay Kit (Promega, Cat. no. E1501, Lot. no. 0000221803)
- Device: plate reader
Key result
Parameter:
other: maximum luciferase activity induction
Remarks:
(mean of 3 replicates)
Run / experiment:
exp. 1
Value:
3.87
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Remarks on result:
other: at 2000 µM
Key result
Parameter:
other: maximum luciferase activity induction
Remarks:
(mean of 3 replicates)
Run / experiment:
exp. 2
Value:
5.2
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid
Remarks on result:
other: at 2000 µM
Other effects / acceptance of results:
OTHER EFFECTS: An increase in metabolic activity (cell viability > 150%) was observed in cells showing a positive maximal luciferase intensity (starting at 500 µM in exp.1 and 2).

DEMONSTRATION OF TECHNICAL PROFICIENCY: no information provided

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for vehicle control: The average CV of the luminescence reading for the vehicle control was < 20% (9.6% and 12.5% in exp. 1 and 2, respectively).
- Acceptance criteria met for positive control: The luciferase activity induced by the positive control at a concentration of 64 µM was between 2 and 8 (2.73 and 2.82 in exp. 1 and 2, respectively) and the calculated EC1.5 value was between 7 and 30 µM (25.69 and 17.20 µM in exp. 1 and 2, respectively).

Table 2: Results of the cytotoxicity measurement

 

Concentration [µM]

Cell viability (%)

exp. 1

exp. 2

Mean ± SD

Vehicle control

-

100

100

100 ± 0.0

Positive control

4

104.5

106.5

105.5 ± 1.4

8

103.7

120.0

111.9 ± 11.6

16

114.1

127.0

120.5 ± 9.1

32

127.3

125.9

126.6 ± 1.0

64

120.7

147.7

134.2 ± 19.1

Test item

0.98

110.4

101.6

106.0 ± 6.2

1.95

117.5

115.7

116.6 ± 1.3

3.91

120.9

119.0

119.9 ± 1.4

7.81

120.2

131.8

126.0 ± 8.2

15.63

98.3

133.7

 111.5 ± 31.4

31.25

100.1

134.1

 117.1 ± 24.0

62.50

120.9

154.3

 137.6 ± 23.6

125

129.7

154.0

 141.9 ± 17.2

250

133.3

170.9

152.1 ± 26.6

500

152.7

183.1

167.9 ± 21.5

1000

158.3

184.6

171.4 ± 18.6

2000

194.3

228.5

211.4 ± 24.1

 

Table 3: Overall induction of luciferase activity

 

Concentration [µM]

Fold induction

exp. 1

exp. 2

Mean ± SD

Solvent control

-

1.00

1.00

1.00 ± 0.00

Positive control

4

1.17

1.11

1.14 ± 0.04

8

1.14

1.25

1.20 ± 0.08

16

1.37

1.50

1.43 ± 0.09

32

1.58*

1.55*

1.57 ± 0.02*

64

2.73*

2.82*

2.77 ± 0.06*

Test item

0.98

1.05

0.94

0.99 ± 0.08

1.95

0.94

0.99

0.97 ± 0.04

3.91

0.96

1.04

1.00 ± 0.05

7.81

0.98

0.94

0.96 ± 0.03

15.63

1.05

1.08

1.07 ± 0.02

31.25

1.09

0.98

1.04 ± 0.08

62.50

1.06

1.17

1.11 ± 0.08

125

1.19

1.30

1.24 ± 0.08

250

1.29

1.37

1.33 ± 0.06

500

1.72*

1.63*

1.67 ± 0.06*

1000

2.13*

2.34*

2.23 ± 0.15*

2000

3.87*

5.20*

4.54 ± 0.94*

*: significant induction according to Student’s T-test, p<0.05

Interpretation of results:
other: inconclusive
Remarks:
according to OECD TG 442D
Conclusions:
The test item did induce a significant increase of luciferase activity in the transgenic KeratinoSens™ cell line in at least two independent experiment runs. Due to interference of the test item with the test system the test has to be considered as inconclusive.
Executive summary:

In the first experiment, a max luciferase activity (Ir„,) induction of 3.87 was determined at a test itemconcentration of 2000.00 pM. The corresponding cell viability was 194.3%. The lowest testedconcentration with a significant luciferase induction >1.5 (1.72) was found to be 500.00 pM. Thecorresponding cell viability was >70% (152.7%). The calculated EC1.5 was < 1000 pM (372.41 pM).

In the second experiment, a max luciferase activity (I„) induction of 5.20 was determined at a testitem concentration of 2000.00 pM. The corresponding cell viability was 228.5%. The lowest testedconcentration with a significant luciferase induction >1.5 (1.63) was found to be 500.00 pM. Thecorresponding cell viability was >70% (183.1%). The calculated EC1.5 was < 1000 pM (374.4 pM).Adose response for luciferase activity induction was observed for each individual run as well as foran overall luciferase activity induction.

However, for test item concentrations inducing a luciferase activity >1.5 an increased cell viabilityabove >150% could be observed in parallel. This cellular reaction indicates interference of the testitem with the test system and might be related to a cellular stress reaction. Based on theseobservations the results cannot be interpreted properly.Therefore, under the condition of this study the results of the test item are considered asinconclusive.

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
10 May - 07 June 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 442B (Skin Sensitization: Local Lymph Node Assay: BrdU-ELISA)
Version / remarks:
22 July 2010
Deviations:
yes
Remarks:
/ No data given in study report about results of range finding study, 4 days of acclimatisation (instead of 5), CBA/N strain used (instead of CBA/JN)
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA): BrdU-ELISA
Species:
mouse
Strain:
CBA
Remarks:
, CBA/N, SPF
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Central Lab. Animal Inc., Republic of Korea
- Females nulliparous and non-pregnant: not specified
- Age at study initiation: 9 weeks (Pretest and Main test)
- Weight at study initiation: 18.8 – 21.6 g (Pretest) and 17.6 – 22.2 (Main test)
- Housing: 2 – 3 animals/cage in Polysulfone cage ( 200x320x140 (mm))
- Diet: Pelleted rodent chow (Teklad Certified Irradiated Global 18% Protein Rodent Diet 2918C, Envigo RMS Inc., U.S.A.), ad libitum
- Water: Public tap water (filtered and irradiated by UV light), ad libitum
- Acclimation period: 4 days
- Indication of any skin lesions: no

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.2 – 23.0 (main study)
- Humidity (%): 45.9 – 54.6 (main study)
- Air changes (per hr): 10 - 15
- Photoperiod (hrs dark / hrs light): 12/12
Vehicle:
acetone/olive oil (4:1 v/v)
Remarks:
(AOO)
Concentration:
5, 25, 100%
No. of animals per dose:
5
Details on study design:
PRE-SCREEN TESTS:
In the pre-screen test, 25 μL of five different concentrations of the test item (5, 10, 25, 50 and 100% dissolved in AOO) were applied to the dorsum of both ears of all animals (2 mice/ concentration), once a day for 3 consecutive days. All animals were observed for mortality, general condition and clinical signs for 6 days. Body weights were recorded prior to dosing (Day 1) and on the day of necropsy (Day 6). Furthermore, erythema measurements were performed for 6 days, ear thickness was measured on Day 1 (pre-dose), Day 3 (approximately 48 hours after the first dose) and Day 6 (the day of necropsy). Additionally the ears were punched after sacrifice about 1 mm from the outside of the ear and tissues of both sides were weighed together.
No information is given in the report about the results of the range finding test.
- Compound solubility: 100%

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local Lymph Node Assay: BrdU-ELISA: The proliferative capacity of lymph node cells was determined by the incorporation of BrdU measured in a photometer.
- Criteria used to consider a positive response: BrdU incorporation in test item group at least 1.6-fold higher compared to control group (indicated by the Stimulation Index (SI)), proven validity (by a positive result of positive control group)

TREATMENT PREPARATION AND ADMINISTRATION:
25 μL of three different concentrations of the test item (5, 25 and 100% dissolved in AOO) as well as of the vehicle control (AOO) and positive control substance (hexyl cinnamic aldehyde) were applied to the dorsum of both ears of all animals (5 mice/ concentration), once a day for 3 consecutive days. All animals were observed for mortality, general condition and clinical signs for 6 days. Body weights were recorded prior to dosing (Day 1) and on the day of necropsy (Day 6). Furthermore, erythema measurements were performed for 6 days, ear thickness was measured on Day 1 (pre-dose), Day 3 (approximately 48 hours after the first dose) and Day 6 (the day of necropsy). On day 5, 500 μL of a Bromodeoxyuridine (BrdU) (10 mg/mL in phosphate buffered saline (PBS)) solution were injected intraperitoneally. 24 hours later, the animals were sacrificed and the ears were punched about 1 mm from the outside of the ear and tissues of both sides were weighed together. The draining lymph nodes of each ear were excised A single cell suspension of lymph node cells was prepared from each mouse by gentle mechanical disaggregation through a 70 μm nylon mesh. The lymph node cells were re-suspended in PBS to achieve an optimized volume (based on the mean absorbance within 0.1 - 0.2 in the negative control group). The incorporation of BrdU into lymph node cells was determined using a commercial cell proliferation assay kit (Roche Applied Science, Mannheim, Germany). After fixation and denaturation of the lymph node cells, anti BrdU antibody was added. After removal of the antibody the substrate solution was added. The chromogen formation was determined by measurement of the absorbance at 370 nm (reference wavelength = 492 nm) by an ELISA Reader (PowerWave XS, BioTek Instruments, Inc., U.S.A.).
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
Bartlett’s test was employed on homogeneity of variance (significance level: 0.05) for body weights, ear thickness, ear weight and stimulation index data.
One-way analysis of variance (ANOVA) was employed on homogeneous data.
Dunnett’s ttest was applied for multiple comparisons (significance levels: 0.05 and 0.01, one-tailed) between the negative control group and each of the test substance groups or positive control substance group. Since it was not significant, Kruskal-Wallis test was employed on heterogeneous data and Steel’s test was applied for multiple comparisons (significance levels: 0.05 and 0.01, one-tailed) between the negative control group and each of the test substance groups or positive substance group.
A statistical program (version 9.3, SAS Institute Inc., U.S.A.) was used for all analyses.
Positive control results:
The positive control substance (25% hexyl cinnamic aldehyde (Batch number: MKBX3483V, Sigma-Aldrich Co., U.S.A.) in AOO) induced a positive reaction, determined by a SI of 2.11. A significant, but only slight increase was observed in erythema, ear thickness and ear weight and a significant increase in SI compared to the negative control group. No differences were observed regarding to clinical signs or body weight compared to the negative control group.
Key result
Parameter:
SI
Remarks:
/ mean of 5 animals
Value:
0.66
Test group / Remarks:
5 % test group
Key result
Parameter:
SI
Remarks:
/ mean of 5 animals
Value:
2.28
Test group / Remarks:
25 % test group
Key result
Parameter:
SI
Remarks:
/ mean of 5 animals
Value:
2.16
Test group / Remarks:
100 % test group
Parameter:
SI
Remarks:
/ mean of 5 animals
Value:
2.11
Test group / Remarks:
positive control group
Cellular proliferation data / Observations:
CELLULAR PROLIFERATION DATA
Significantly increased lymphoproliferation (SI ≥ 1.6) was observed for the test item at treatment concentrations of 25 and 100%. At 5% of the test item, no significant increase in the lymphoproliferation was observed.


DETAILS ON STIMULATION INDEX CALCULATION
The SI is derived by dividing the mean BrdU labeling index of each test item group or positive control group by the mean BrdU labeling index of the vehicle group.

EC3 CALCULATION: SI values were calculated to be above 1.6 at doses of 50 and 100% in the main study. Thus, EC1.6 value was calculated to be 16.6% following the equation:

EC1.6 =c + [(1.6-d)/(b-d)] x (a-c)

a = dose concentration with higher SI
b = higher SI value
c = dose concentration with lower SI
d = lower SI value

CLINICAL OBSERVATIONS: No mortality or symptoms of systemic toxicity were observed in any treatment group. No signs of irritation or any other local effect were observed in any treatment group.
Significant, but only slight increases in ear thickness (<25%) were observed on Day 3 and 6 and in ear weight (<10%) on Day 6 in the treatment groups 25 and 100%.

BODY WEIGHTS
There were no significant differences compared to the negative control group.

Table 1: Mean Stimulation Indices

Compound

Concentration [%]

BrdU labeling Index

Mean BrdU labeling Index ± SD

Stimulation index (SI)

Mean SI ± SD

AOO

100

0.87

0.80 ± 0.12

1.09

1.00 ± 0.15

0.93

1.16

0.81

1.01

0.61

0.76

0.79

0.99

Test substance

5

0.5

0.53 ± 0.18

0.62

0.66 ± 0.22

0.32

0.4

0.8

0.99

0.45

0.56

0.6

0.75

25

2.03

1.83 ± 0.12

2.52

2.28 ± 0.15
**

1.74

2.17

1.88

2.34

1.71

2.13

1.81

2.26

100

1.86

1.74 ± 0.19

2.31

2.16 ± 0.24
**

1.72

2.14

1.83

2.28

1.41

1.75

1.87

2.33

HCA

25

1.81

1.70 ± 0.38

2.26

2.11 ± 0.47
**

1.45

1.8

1.26

1.57

2.25

2.8

1.72

2.14

Table 2: Mean Body Weights

Compound

Concentration [%]

Body weight [g] (Mean ± SD)

Day 1

Day 6

AOO

100

20.5 ± 1.7

20.7 ± 1.6

Test substance

5

20.2 ± 1.1

20.3 ± 1.3

25

20.6 ± 0.9

20.5 ± 0.8

100

20.2 ± 1.0

20.4 ± 1.5

HCA

25

20.1 ± 1.6

21.0 ± 1.2

Table 3: Mean Erythema Scores

Compound

Concentration [%]

Erythema scores (Mean ± SD)

Day 1

Day 2

Day 3

Day 4

Day 5

Day 6

AOO

100

0 ± 0

0 ± 0

0 ± 0

0 ± 0

0 ± 0

0 ± 0

Test substance

5

0 ± 0

0 ± 0

0 ± 0

0 ± 0

0 ± 0

0 ± 0

25

0 ± 0

0 ± 0

0 ± 0

0 ± 0

0 ± 0

0 ± 0

100

0 ± 0

0 ± 0

0 ± 0

0 ± 0

1 ± 1

1 ± 1

HCA

25

0 ± 0

0 ± 0

1 ± 1

1 ± 1

1 ± 0 **

1 ± 0 **

Table 4: Mean Ear Thickness

Compound

Concentration [%]

Ear thickness [mm] (Mean ± SD)

Day 1

Day 3

Day 6

AOO

100

0.19 ± 0.00

0.19 ± 0.00

0.19 ± 0.00

Test substance

5

0.19 ± 0.00

0.19 ± 0.00

0.19 ± 0.00

25

0.19 ± 0.00

0.19 ± 0.00 **

0.20 ± 0.00 **

100

0.19 ± 0.00

0.20 ± 0.00 **

0.20 ± 0.00 **

HCA

25

0.19 ± 0.00

0.20 ± 0.00 **

0.21 ± 0.00 **

Table 5: Mean Ear Weights

Compound

Concentration [%]

Ear weight [mg] (Mean ± SD)

AOO

100

12.6 ± 0.3

Test substance

5

12.8 ± 0.3

25

13.7 ± 0.7 **

100

13.5 ± 0.6 *

HCA

25

14.3 ± 0.4 **

*   statistically significant difference vs. vehicle control group (p<0.05)

** statistically significant difference vs. vehicle control group (p<0.01)

AOO = Acetone: Olive oil (4:1 (v/v) mixture)

HCA = Hexyl cinnamic aldehyde

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
CLP: Skin Sens. 1B
Executive summary:

The skin sensitisation potential of the test substance was determined by a LLNA test using the BrdU ELISA method according to OECD Guideline 442B in compliance with GLP (2017). After treatment of CBA/N mice with the test substance, stimulation indices of 0.66, 2.28 and 2.16 were determined at the concentrations of 5, 25 and 100%, respectively. The EC1.6 value was calculated as 16.6%.

Based on this result, the test substance is considered as a weak skin sensitiser (Skin Sens. 1B).

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

Sensitsation

The skin sensitisation potential of the test substance was first determined by the skin sensitisation in vitro test battery in compliance with GLP.

In the Human Cell Line Activation Test (h-CLAT) (OECD 442E) (2016), THP-1 cells were treated for 24 h with concentrations ranging from 83.7 to 300 μg/mL, resulting in a relative fluorescence intensity (RFI) of CD54 >200% (at 83.7 μg/mL and between 120.6 and 300 μg/mL in exp. 1 and at 173.6 and 300 μg/mL in exp. 2) and of CD86 < 150% (at all concentrations in both exp., except at 300 μg/mL in exp. 1).

Based on this result, the h-CLAT prediction is considered positive for skin sensitisation.

In the In Chemico Skin Sensitisation: Direct Peptide Reactivity Assay (DPRA) (OECD 442C) (2017), model synthetic peptides containing either lysine or cysteine were incubated for at least 22 h with 25 mM and 5 mM, respectively. The mean depletion of cysteine-containing peptides was 6.45%, while the mean peptide depletion of lysine-containing peptides was -0.95, resulting in an overall mean of cysteine and lysine peptide depletion of 3.23% and therefore a negative outcome of the test (threshold for a positive result was > 6.38%).

Based on this result, the DPRA showed no or minimal peptide reactivity of the test substance.

In the In Vitro Skin Sensitisation: ARE-Nrf2 Luciferase Test (OECD 442D) (2017), the KeratinoSens™ cells were incubated in two experiments for 48 h with concentrations ranging from 0.98 to 2000 μM. This resulted in a maximum luciferase activity induction of 3.87 and 5.20 with corresponding cell viabilities of 194.3 and 228.5% at 2000 μM, in exp. 1 and 2, respectively. The lowest tested concentration with a significant luciferase induction of >1.5 (1.72 and 1.63 in exp. 1 and 2, respectively) was found to be 500.00 µM with corresponding cell viabilitis of >70% (152.7 and 183.1% in exp. 1 and 2, respectively). The EC1.5 values of 372.41 and 374.4 µM were calculated for exp. 1 and 2, respectively.

As the test item concentrations inducing a luciferase activity >1.5 also increased the cell viability to over 150%, indicating an interference of the test item with the test system and the observed effect might be related to a cellular stress reaction, the results cannot be interpreted properly.

As the results of the in vitro tests did not allow a definitive prediction, the skin sensitisation potential of the test substance was in addition determined by a LLNA test using the BrdU ELISA method according to OECD Guideline 442B in compliance with GLP (2017). After treatment of CBA/N mice with the test substance, stimulation indices of 0.66, 2.28 and 2.16 at the concentrations of 5, 25 and 100%, respectively. The EC1.6 value was calculated as 16.6%.

Based on this result, the test substance is considered as a weak skin sensitiser (Skin Sens. 1B).

In conclusion, based on the available data the test substance is considered to be a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

The available data on skin sensitisation meet the criteria for classification according to Regulation (EC) 1272/2008, and the substance is therefore classified as skin sensitiser Category 1B (H317).