3-octoxypropane-1,2-diol

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation, other

Remarks:

In silico assessment

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

An in silico assessment is mentioned in the ECHA guidance as one of the non-animal tests that may be performed as part of a weight of evidence approach for the endpoint skin sensitization.

Qualifier:

no guideline required

Principles of method if other than guideline:

An in silico assessment was performed with DEREK NEXUS version 6.0.1

GLP compliance:

no

Justification for non-LLNA method:

Since 11 October 2016 it is legally required to consider all available information for the endpoint skin sensitisation and to use a non in vivo test strategy based on in chemico, in silico and in vitro skin tests combined in a weight-of-evidence approach. An in vivo test (LLNA) is only allowed as last resort. DEREK results are adequate to be used in a weight-of-evidence approach together with in chemico/in vitro studies to complete the endpoint skin sensitisation.

Key result

Run / experiment:

other: Caprylyl Glyceryl Ether

Parameter:

other: Prediction of skinsensitization

Remarks on result:

no indication of skin sensitisation

Other effects / acceptance of results:

Caprylyl Glyceryl Ether does not contain any unclassified or misclassified features and is consequently predicted to be a non-sensitizer (see prediction in study report).

Interpretation of results:

other: study is part of a weight of evidence approach and is not used for classification on its own

Conclusions:

Caprylyl Glyceryl Ether is predicted to be not sensitizing to the skin.

Executive summary:

DEREK NEXUS version 6.0.1 did not yield any alerts for skin sensitization for the test item. Additionally, Caprylyl Glyceryl Ether does not contain any unclassified or misclassified features and is consequently predicted to be a non-sensitizer.

Reference 2

Endpoint:

skin sensitisation: in chemico

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

02 Sep 2019 to 06 sep 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The validated in chemico skin sensitization test is the DPRA assay, which is recommended in international guidelines (e.g. OECD) and mentioned in the ECHA guidance as the in chemico test to be performed as part of weight of evidence.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

18 June 2019

Deviations:

no

GLP compliance:

yes

Type of study:

direct peptide reactivity assay (DPRA)

Justification for non-LLNA method:

A validated in chemico skin sensitization test is the DPRA assay, which is recommended in international guidelines (e.g. OECD) and mentioned in the ECHA guidance as one of the non-animal tests to be performed as part of weight of evidence.

Details on the study design:

TEST ITEM PREPARATION:
Solubility of the test item in an appropriate solvent was assessed before performing the DPRA. An appropriate solvent dissolved the test item completely, i.e., by visual inspection the solution had to be not cloudy nor have noticeable precipitate. The following solvent was evaluated: acetonitrile (ACN).
Test item stock solutions were prepared freshly for each reactivity assay.
For both the cysteine and lysine reactivity assay 34.78 mg of test item was pre-weighed into a clean amber glass vial and dissolved, just before use, in 1702 µL ACN after vortex mixing to obtain a 100 mM solution. Visual inspection of the forming of a clear solution was considered sufficient to ascertain that the test item was dissolved. The test item, positive control and peptide samples were prepared less than 4 hours before starting the incubation of the cysteine (cys) or lysine (lys) reactivity assay, respectively.

TEST SYSTEM
Test system: Synthetic peptides containing cysteine (SPCC) (Ac RFAACAA COOH) or synthetic peptides containing lysine (SPCL) (Ac RFAAKAA COOH). The molecular weight is 750.9 g/mol for SPCC and 775.9 g/mol for SPCL.
Source: JPT Peptide Technologies GmbH, Berlin, Germany.
Storage: The peptides were stored in the freezer (≤ 15°C) for a maximum of 6 months.
Incubation: The samples (reference controls, calibration solutions, co-elution control, positive controls and test item samples) were placed in the autosampler in the dark and incubated at 25±2.5°C. The incubation time between placement of the samples in the autosampler and analysis of the first RCcysB- or RClysB-sample was 24.2 hours. The time between the first RCcysB- or RClysB-injection and the last injection of a cysteine or lysine sequence did not exceed 30 hours.
Analysis: All samples were analyzed according to the HPLC method presented in Table 1. (See 'other information on materials and methods').
The HPLC sequences of the cysteine and lysine reactivity assay for the test item are presented in Table 2. (See 'other information on materials and methods').

POSITIVE CONTROL: Cinnamic aldehyde
- Purity: 99.1%
- Batch: MKCB9907
- Expiry of batch: 30 November 2021

DATA EVALUATION
The concentration of SPCC or SPCL was spectrophotometrically determined at 220 nm in each sample by measuring the peak area of the appropriate peaks by peak integration and by calculating the concentration of peptide using the linear calibration curve derived from the standards.
The Percent Peptide Depletion was determined in each sample by measuring the peak area and dividing it by the mean peak area of the relevant reference controls C according to the following formula:
Percent Peptide Depletion= [1-(Peptide Peak Area in Replicate Injection (at 220 nm))/Mean Peptide Peak Area in Reference Controls (at 220 nm))]×100
In addition, the absorbance at 258 nm was determined in each sample by measuring the peak area of the appropriate peaks by peak integration. The ratio of the 220 nm peak area and the 258 nm peak was used as an indicator of co-elution. For each sample, a ratio in the range of 90%
DATA INTERPRETATION (see Table 3 `other information on materials and method')
The mean Percent Cysteine Depletion and Percent Lysine Depletion were calculated for the test item. Negative depletion was considered as “0” when calculating the mean. By using the Cysteine 1:10 / Lysine 1:50 prediction model (see table below), the threshold of 6.38% average peptide depletion was used to support the discrimination between a skin sensitizer and a non-sensitizer.

ACCEPTABILITY CRITERIA
The following criteria had to be met for a run to be considered valid:
a) The standard calibration curve had to have a r2>0.99.
b) The mean Percent Peptide Depletion value of the three replicates for the positive control cinnamic aldehyde had to be between 60.8% and 100% for SPCC and between 40.2% and 69.0% for SPCL.
c) The maximum standard deviation (SD) for the positive control replicates had to be <14.9% for the Percent Cysteine Peptide Depletion and <11.6% for the Percent Lysine Peptide Depletion.
d) The mean peptide concentration of Reference Controls A had to be 0.50 ± 0.05 mM.
e) The Coefficient of Variation (CV) of peptide areas for the nine Reference Controls B and C in ACN had to be <15.0%.
The following criteria had to be met for a test item’s results to be considered valid:
a) The maximum SD for the test item replicates had to be <14.9% for the Percent Cysteine Depletion and <11.6% for the Percent Lysine Depletion.
b) The mean peptide concentration of the three Reference Controls C in the appropriate solvent had to be 0.50±0.05 mM.

Key result

Run / experiment:

other: Cysteine Reactivity Assay

Parameter:

other: Mean Percentage SPCC depletion

Value:

0.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

CV Between reference controls: 0.6%

Positive controls validity:

valid

Remarks:

mean percentage SPCC: 71.1% ± 0.2%.

Key result

Run / experiment:

other: Lysine Reactivity Assay

Parameter:

other: Mean Percentage SPCL depletion

Value:

0.4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

CV between reference controls: 0.4%

Positive controls validity:

valid

Remarks:

Mean percentage SPCL: 62.3% ± 3.4%

Other effects / acceptance of results:

- Upon preparation as well as after incubation of the SPCC and SPCL test item samples, no precipitate or phase separation was observed in any of the samples.
- In the cysteine reactivity assay the test item showed 0.8% SPCC depletion while in the lysine reactivity assay the test item showed 0.4% SPCL depletion. The mean of the SPCC and SPCL depletion was 0.6% and as a result the test item was negative in the DPRA and was classified in the “no or minimal reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model.

Acceptability of the Direct Peptide Reactivity Assay (DPRA)

	Cysteine reactivity assay		Lysine reactivity assay
	Acceptability criteria	Results for SPCC	Acceptability criteria	Results for SPCL
Correlation coefficient (r^2) standard calibration curve	>0.99	1.000	>0.99	1.000
Mean peptide concentration RC-A samples (mM)	0.50 ± 0.05	0.506 ± 0.002	0.50 ± 0.05	0.502 ± 0.001
Mean peptide concentration RC-C samples (mM)	0.50 ± 0.05	0.507 ± 0.003	0.50 ± 0.05	0.501 ± 0.002
CV (%) for RC samples B and C	<15.0	0.6	<15.0	0.4
Mean peptide depletion cinnamic aldehyde (%)	60.8-100	71.1	40.2-69.0	62.3
SD of peptide depletion cinnamic aldehyde (%)	<14.9	0.2	<11.6	3.4
SD of peptide depletion for the test item (%)	<14.9	0.2	<11.6	0.2

RC = Reference Control; CV = Coefficient of Variation; SD = Standard Deviation.

SPCC and SPCL Depletion, DPRA Prediction and Reactivity Classification forthe Test Item

Test item	SPCC depletion		SPCL depletion		Mean of SPCC and SPCL depletion	DPRA prediction and reactivity classification
	Mean	± SD	Mean	± SD		Cysteine 1:10 / Lysine 1:50 prediction model
Saskine ™ 80	0.8%	±0.2%	0.4%	±0.2%	0.6%	Negative: No or minimal reactivity

SD = Standard Deviation.

Interpretation of results:

other: study is part of a weight of evidence approach and is not used for classification on its own

Conclusions:

In a DPRA performed according to OECD TG 442C the mean of the SPCC and SPCL depletion was 0.6% and the substance is classified in the “no or minimal reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model.

Executive summary:

A DPRA study was performed according to the OECD TG 442C and in accordance with GLP principles. SPCC and SPCL Percent Depletion Values were calculated and used in a prediction model which allows assigning the test item to one of four reactivity classes used to support the discrimination between sensitizers and non-sensitizers. The relative peptide concentration was determined by High-Performance Liquid Chromatography (HPLC) with gradient elution and spectrophotometric detection at 220 nm and 258 nm. The validation parameters, i.e. calibration curve, mean concentration of Reference Control (RC) samples, the CV for RC samples, the mean percent peptide depletion values for the positive control with its standard deviation value and the standard deviation value of the peptide depletion for the test item, were all within the acceptability criteria for the DPRA. Since all acceptability criteria were met this DPRA is considered to be valid. No coelution of the test item with SPCC or SPCL was observed.

In the cysteine reactivity assay the test item showed 0.8% SPCC depletion while in the lysine reactivity assay the test item showed 0.4% SPCL depletion. The mean of the SPCC and SPCL depletion was 0.6% and as a result the test item was considered to be negative in the DPRA and classified in the “no or minimal reactivity class” when using the Cysteine 1:10 / Lysine 1:50 prediction model.

 

Reference 3

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

22 August - 1 November 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The validated in vitro skin sensitization test is the KeratinoSens TM, which is recommended in international guidelines (e.g. OECD) as the in vitro test to be performed as part of weight of evidence.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

June, 2018

Deviations:

no

GLP compliance:

yes

Type of study:

activation of keratinocytes

Justification for non-LLNA method:

The validated in vitro skin sensitization test is the KeratinoSens TM, which is recommended in international guidelines (e.g. OECD) as the in vitro test to be performed as part of weight of evidence.

Details on the study design:

Skin sensitisation (In vitro test system) - Details on study design:

Controls:
Positive control: ethylene dimethacrylate glycol, 7.8-250 uM, tested in triplicate, final concentration DMSO of 1%; Negative control: DSMO (vehicle) (1% in exposure medium); Blank: on each plate three blank wells were tested (no cells and no treatment) to assess background values.

Number of replicates: for each repetition, three replicates were used for the luciferase activity measurements, and one parallel replicate used for the MTT cell viability assay.

Test system:
A transgenic cell line having a stable insertion of the luciferase reporter gene under the control of the ARE-element is used (e.g. the KeratinoSensTM cell line). Upon receipt, cells are propagated (e.g. 2 to 4 passages) and stored frozen as a homogeneous stock. Cells from this original stock can be propagated up to a maximum passage number from the frozen stock (i.e. 25) and are employed for routine testing using the appropriate maintenance medium.
Cells were subcultured upon reaching 80-90% confluency. To maintain the integrity of the response, the cells were grown for more than one passage from the frozen stock, and were not cultured for more than 25 passages from the frozen stock (P+25).
One day prior to testing cells were harvested, and distributed into 96-well plates (10,000 cells/well) in basic medium. For each repetition, three replicates were used for the luciferase activity measurements, and one parallel replicate used for the MTT cell viability assay. The cells were incubated overnight in the incubator.
The passage number used was P+13 in experiment 1, P+15 in experiment 2 and P+4 in experiment 3.

Test item preparation:
No correcction was made for the composition/purity of the test item. The test item was dissolved in DMSO to a final concentration of 40 mg/mL (clear colourless solution). From this stock 11 splike solutions in DMSO were prepared (2-fold dilution series). The stock and spike solution were diluted 25-fold with exposure medium. These solutions were diluted 4-fold with exposure medium in the assay. No precipitation was observed at the start and end of the incubation period in the 96-well plates.

Media:
Basic medium: Dulbecco's minimal (DMEM glutamax) supplemented with 9.1% (v/v) heat-inactivated) (56C; 30 min) fetal calf serum
Maintenance medium: Dulbecco's minimal (DMEM glutamax) supplemented with 9.1% (v/v) heat-inactivated (56C; 30 min) fetal calf serum and geneticin (500 ug/mL)
Exposure medium: Dulbecco's minimal (DMEM glutamax) supplemented with 1% (v/v) heat-inactivated (56C; 30 min) fetal calf serum

Treatment of cells:
The medium was removed and replaced with fresh culture medium (150 uL culture medium containing serum but without Geneticin) to which 50 uL of the 25-fold diluted test chemical and control items were added. Three wells per plate were left empty (no cells and no treatment) to assess background values. The treated plates were covered with foil and then incubated for about 48 hours +/- 1 hour at 37+/- 1°C in the presence of 5% CO2.

Luciferase activity measurement:
The Steady-Glo Luciferase Assay Buffer (10 mL) and Steady-Glo Luciferase Substrate (lyophilized) from Promega were mixed together. The assay plates were removed from the incubator and the medium is removed. Then 200 uL of the Steady-Glo Luciferase substrate solution (prior to addition 1:1 mixed with exposure medium) was added to each well. The plates were shaken for at least 5 minutes at room temperature. Plates with the cell lysates were placed in the luminometer to assess the quantitiy of luciferase (integration time two seconds).

Cytotoxicity assessment:
For the KeratinoSensTM cell viability assay, medium was replaced after the 48 hour exposure time with fresh medium containing MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, Thiazolyl blue tetrazolium bromide; CAS No. 298-93-1) and cells were incubated for 3 - 4 hours at 37°C ± 1.0°C in the presence of 5% CO2. The MTT medium was then removed and cells were lysed overnight by adding 10% SDS solution to each
well. After shaking, the absorption was measured at 570 nm with the TECAN Infinite® M200 Pro Plate Reader.

Positive control results:

The EC1.5 of the positive control was within two standard deviations of the historical mean (52 μM, 59 μM and 33 μM in experiment 1, 2 and 3, respectively). A dose response was observed and the induction at 250 μM was higher than 2-fold (3.12-fold, 2.69-fold and 3.41-fold in experiment 1, 2 and 3, respectively).

Key result

Run / experiment:

other: Experiment 1

Parameter:

other: Imax

Value:

1.1

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: no EC1.5 could be calculated

Key result

Run / experiment:

other: Experiment 2

Parameter:

other: Imax

Value:

1.72

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: EC1.5: 8.8 μg/mL

Key result

Run / experiment:

other: Experiment 3

Parameter:

other: Imax

Value:

1.91

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: EC1.5: 1.2 μg/mL

Other effects / acceptance of results:

The test item showed toxicity. In the first experiment, IC30 was 0.97 μg/mL and IC50 was 14 μg/mL. In the second experiment, IC30 was 39 μg/mL and the IC50 was 59 μg/mL. In the third experiment, IC30 was 52 μg/mL and IC50 was 68 μg/mL.

All experiments passed the acceptance criteria:
- The luciferase activity induction obtained with the positive control, Ethylene dimethacrylate glycol, was statistically significant above the threshold of 1.5-fold in at least one concentration.
- The EC1.5 of the positive control was within two standard deviations of the historical mean (52 μM, 59 μM and 33 μM in experiment 1, 2 and 3, respectively. Historical control range: -2.8 - 120). A dose response was observed and the induction at 250 μM was higher than 2-fold (3.12-fold, 2.69-fold and 3.41-fold in experiment 1, 2 and 3, respectively).
- Finally, the average coefficient of variation of the luminescence reading for the vehicle (negative) control DMSO was below 20% (12%, 5.3% and 14% in experiment 1 and 2, respectively).

Table 1 Overview Luminescence induction and Cell viabiliby of the test item in experiment 1, 2 and 3

Concentration (μg/mL)	0.20	0.39	0.78	1.6	3.1	6.3	13	25	50	100	200	400
Exp 1 luminescence	1.00	0.92	0.93	0.89	1.10	0.97	0.98	1.03	0.87	0.22	0.00	0.00
Exp 1 viability (%)	78.8	77.1	71.8	64.4	58.7	54.3	50.3	47.4	38.9	4.0	-0.2	-0.2
Exp 2 luminescence	1.07	1.09	1.13	1.22	1.28	1.43	1.61***	1.72***	1.24	0.15	0.00	0.00
Exp 2 viability (%)	101.4	100.1	97.7	99.0	95.1	93.5	87.1	82.9	59.6	3.3	-0.4	-0.2
Exp 3 luminescence	1.39	1.42	1.41	1.60***	1.69***	1.81***	1.91***	1.90***	1.58***	0.55	0.00	-0.01
Exp 3 viability (%)	107.7	99.0	97.9	93.4	92.6	83.4	84.0	78.8	72.9	10.6	-0.3	-0.3

*** p<0.001 Student's t test

Table 2 Overview Luminescence induction and cell viability positive control EDMG in experiment 1, 2 and 3

Concentration (μM)  7.8  16  31  63  125  250  Exp 1 luminescence  1.17  1.14  1.36  1.57***  2.02***  3.12***  Exp 1 viability (%)  104.5  113.6  105.6  96.0  99.8  93.9  Exp 2 luminescence  1.00 1.11   1.25  1.53***  2.02***  2.69***  Exp 2 viability (%)  109.7  101.8  98.8  100.7  103.9  104.0  Exp 3 luminescence  1.18  1.29  1.48  1.77***  2.31***  3.41***  Exp 3 viability (%)  121.4  129.6  129.3  131.5  130.7  142.5

*** p<0.001 Student's t test

Table 3 Overview EC1.5, IMax, IC30 and IC50 values

EC1.5 (μg/mL)  Imax  IC30 (μg/mL)  IC50 (μg/mL) Test item Experiment 1  NA  1.10  0.97  14 Test item Experiment 2  8.8  1.72  39 59 Test item Experiment 3  1.2 1.91   52  68    EC1.5 (μM)  Imax  IC30 (μM)  IC50 (μM)  Pos control Experiment 1  52  3.12  NA  NA  Pos control Experiment 2  59  2.69  NA  NA  Pos control Experiment 3  33  3.41  NA  NA

NA=Not applicable

Interpretation of results:

other: study is part of a weight of evidence approach and is not used for classification on its own

Conclusions:

Under the experimental conditions described in this report, the substance is classified as positive for activation of the antioxidant/electrophile responsive element (ARE)-dependent pathway in keratinocytes.

Executive summary:

A KeratinoSens™ assay was performed according to OECD guidelines and in accordance with GLP principles. The highest test concentration was the highest dose required in the current guideline. No precipitate was observed at any dose level tested. Three independent experiments were performed. Overall it is concluded that the test conditions were adequate and that the test system functioned properly.

In the first experiment, the test item showed toxicity (IC30 value of 0.97 μg/mL and IC50 value of 14 μg/mL). No biologically relevant induction of the luciferase activity (no EC1.5 value) was measured at any of the test concentrations. The maximum luciferase activity induction (Imax) was 1.10-fold leading to an individual run conclusion of negative. In the second experiment, the test item showed toxicity (IC30 value of 39 μg/mL and IC50 value of 59 μg/mL). A biologically relevant, dose-related induction of the luciferase activity (EC1.5 value of 8.8 μg/mL) was measured. The maximum luciferase activity induction (Imax) was 1.72-fold leading to an individual run conclusion of positive. Since the first two experiments were not concordant a third experiment was performed to provide a final conclusion. In the third experiment, the test item showed toxicity (IC30 value of 52 μg/mL and IC50 value of 68 μg/mL). A biologically relevant, dose-related induction of the luciferase activity (EC1.5 value of 1.2 μg/mL) was measured. The maximum luciferase activity induction (Imax) was 1.91-fold leading to an individual run conclusion of positive. The susbstance is classified as positive in the KeratinoSensTM assay since positive results (>1.5-fold induction) were observed at test concentrations < 200 μg/mL with a cell viability of >70% compared to the vehicle control in two out of three experiments.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

A DEREK prediction on the skin sensitizing potential of Saskine™ 80 yielded no alerts for skin sensitization. All structural fragments of Saskine™ 80 were found in DEREKs negative prediction database and therefore the substance is predicted to be not skin sensitizing to the skin. The DPRA showed that Saskine™ 80 does not interact with cysteine or lysine moieties and therefore key event 1 of the skin sensitization AOP, a reaction with endogenous skin proteins, is not expected to take place. The KeratinoSensTM assay was positive as a dose dependent increase in luciferase activity was observed however the applicability of the assay to assess the skin sensitizing properties of this substance is doubted. In the KeratinoSensTM assay luciferase induction is mediated by the Keap1 (Kelch-like ECH-associated protein 1)- Nrf2 (nuclear factor-erythroid 2-related factor 2)-ARE (antioxidant response element) pathway. A study showed that an alkyl glyceryl ether, chimyl alcohol (CAS: 6145-69-3), can act as an agonist for PPAR-γ1. Both Nrf2 and PPARγ have been shown to play key roles in establishing the cellular antioxidative defence system and direct regulation of the Nrf2 pathway by PPARγ has been described (2),(3). It may be possible that this chemical class of alkyl glyceryl ethers may induce Nrf2 via PPAR-γ and thus inadvertently induce luciferase production. Considering Saskine™ 80 is an alkyl glyceryl ether the positive result obtained may well be a false positive result and thus no conclusion on key event 2 can be drawn with sufficient confidence. Step 2, addressing key event 3 with the U-SENSTM assay was omitted as the cytotoxicity properties of Saskine™ 80 will preclude the experimental runs as positive regardless of whether activation of dendritic cells is observed. Instead a h-CLAT (OECD 442E) performed with the analogue Saskine™ 70 was available to assess key event 3. In the assay no dendritic activation (no increase in CD54 and CD86) was observed at non-cytotoxic levels and therefore the outcome was concluded to be negative. Saskine™ 70 is structurally similar to Saskine™ 80, both are alkyl glyceryl ethers. They differ solely by the length of the alkyl chain which is one carbon shorter for Saskine™ 70 compared to Saskine™ 80 (see appendix 1). Similar to Saskine™ 80, Saskine™ 70 was negative in the DEREK and DPRA and both substances showed to be (false) positive in the KeratinoSens assay. Considering the high structural similarity and similar behavior in other skin sensitization in vitro assays a similar response in the h-CLAT is expected for Saskine™ 80. As a result, the third key event is considered negative for Saskine™ 80 based on the read-across of the negative h-CLAT result for Saskine™ 70. Based on the experimental results obtained and information provided by the structurally similar analogue Saskine™ 70 sufficient evidence is presented to conclude that Saskine™ 80 is not a skin sensitizer and is thus not expected to lead to an allergic response following skin contact. This conclusion is supported by a review prepared by Cosmetic Ingredient Review Expert Panel in which the available skin sensitization data for alkyl glyceryl ethers was evaluated. No skin sensitization incidents were reported and alkyl glyceryl ethers including Saskine™ 80 were regarded as safe for use as cosmetic ingredients(4)

Based on these considerations, it is concluded that Saskine™ 80 does not need to be classified for skin sensitization according to Regulation (EC) No 1272/2008 and related amendments.

1) Yokota, M., Yahagi, S., Tokudome, Y., & Masaki, H. (2018). Chimyl alcohol suppresses PGE2 synthesis by human epidermal

keratinocytes through the activation of PPAR-γ. Journal of Oleo Science, 67(4), 455–462. https://doi.org/10.5650/jos.ess17157

2) Lee, C. (2017). Collaborative Power of Nrf2 and PPAR γ Activators against Metabolic and Drug-Induced Oxidative Injury. Oxidative

Medicine and Cellular Longevity, 2017. https://doi.org/10.1155/2017/1378175

3) Polvani, S., Tarocchi, M., & Galli, A. (2012). PPAR and oxidative stress: Con(β) catenating NRF2 and FOXO. PPAR Research, 2012.

https://doi.org/10.1155/2012/641087

4) Cosmetic Ingredient Review. (2011). Final Safety Assessment On the Safety Assessment of Alkyl Glyceryl Ethers As Used in Cosmetics.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the results of the available studies, the substance does not need to be classified for skin sensitization according to Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments).