Pentan-2-one

Endpoint summary

Description of key information

3 in vitro/in chemico studies were conducted (DPRA, h-CLAT, Keratinosense) that did not indicate sensitizing properties.

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:

weight of evidence

Study period:

2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 442C (In Chemico Skin Sensitisation Assays addressing the Adverse Outcome Pathway key event on covalent binding to proteins)

GLP compliance:

yes (incl. QA statement)

Type of study:

direct peptide reactivity assay (DPRA)

Justification for non-LLNA method:

The DPRA is one in a trio of non-animal screen studies required to be conducted in order to determine if an LLNA needs to be conducted.

Specific details on test material used for the study:

Name: Methyl Propyl Ketone
Batch No.: TD21033302
CAS No: 107-87-9
Molecular Weight: 86.13 g/mol
Purity: 94.79%
Physical State: liquid
Colour: colourless
Stability: stable
Storage Conditions: ambient
Expiry Date: 01 January 2023
Safety Precautions: The routine hygienic procedures will be sufficient to assure personnel health and safety.

Details of test system:

cysteine peptide, (Ac-RFAACAA-COOH)

lysine peptide (Ac-RFAAKAACOOH)

Vehicle / solvent:

water

Positive control:

cinnamic aldehyde

Group:

test chemical

Run / experiment:

mean

Parameter:

mean lysine depletion

Value:

0.53 %

At concentration:

0.5 mM

Vehicle controls validity:

valid

Remarks:

Reference control

Negative controls validity:

valid

Remarks:

Co-elution control

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Remarks:

The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Group:

test chemical

Run / experiment:

mean

Parameter:

mean cystein depletion

Value:

1.18 %

At concentration:

0.5 mM

Vehicle controls validity:

valid

Remarks:

Reference control

Negative controls validity:

valid

Remarks:

Co-elution control

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Remarks:

The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Outcome of the prediction model:

negative [in vitro/in chemico]

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 Methyl Propyl Ketone was dissolved in dist. water, based on the results of the pre-experiments.

Based on a molecular weight of 86.13 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.

All test item solutions were freshly prepared immediately prior to use.

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. No precipitation, turbidity or phase separation was observed for any of the samples.

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. No precipitation, turbidity or phase separation was observed for any of the samples.

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 C (RC C_{dist. water}).

The 100 mM stock solution of the test item showed minimal reactivity towards the synthetic peptides. The mean depletion of both peptides was ≤ 6.38% (0.86%). Based on the prediction model 1 the test item can be considered as non-sensitiser.

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions the test item showed minimal reactivity towards both peptides. The test item is considered as a “non-sensitiser”.
The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Executive summary:

The in chemicodirect 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 Methyl Propyl Ketone was dissolved in dist. water, based on the results of the pre-experiments.

Based on a molecular weight of 86.13 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.

All test item solutions were freshly prepared immediately prior to use.

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. No precipitation, turbidity or phase separation was observed for any of the samples.

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. No precipitation, turbidity or phase separation was observed for any of the samples.

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 C (RC C_{dist. water}).

The 100 mM stock solution of the test item showed minimal reactivity towards the synthetic peptides. The mean depletion of both peptides was ≤ 6.38% (0.86%). Based on the prediction model 1 the test item can be considered as non-sensitiser.

 Conclusion

In this study under the given conditions the test item showed minimal reactivity towards both peptides. The test item is considered as a “non-sensitiser”.

The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Reference 2

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 442E (In Vitro Skin Sensitisation assays addressing the key event on activation of dendritic cells on the Adverse Outcome Pathway for skin sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

human Cell Line Activation Test (h-CLAT)

Justification for non-LLNA method:

The h-CLAT is a mandated study to be conducted as part of an initial screen before the need for an LLNA is determined

Specific details on test material used for the study:

Name: Methyl Propyl Ketone
Batch No.: TD21033302
CAS No: 107-87-9
Molecular Weight: 86.13 g/mol
Purity: 94.79%
Physical State: liquid
Colour: colourless
Log KOW: not specified by the sponsor
Stability: stable
Storage Conditions: ambient
Expiry Date: 01 January 2023
Safety Precautions: The routine hygienic procedures were sufficient to assure personnel health and safety.

Details of test system:

THP-1 cell line [442E]

Vehicle / solvent control:

DMSO

Negative control:

DL-Lactic acid

Positive control:

dinitrochlorobenzene (DNCB) [442E]

Positive control results:

The positive controls DNCB and NiSO4 led to upregulation of the cell surface markers CD54 and CD86. The negative control LA did not induce an upregulation of CD54 and CD86.

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

other: CV75 (442E)

Remarks:

CV75 could not be determined due to a lack of toxicity at the highest concentrations

Value:

0 %

At concentration:

1 000 mM

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

RFI CD54>150 [442E]

Remarks:

RFI of CD54 at all the concentrations tested are less than 200%

Value:

89 %

At concentration:

1 000 other: µg/mL

Cell viability:

93.6%

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Group:

test chemical

Run / experiment:

run/experiment 2

Parameter:

RFI CD54>150 [442E]

Remarks:

RFI of CD54 at all the concentrations tested are less than 200%

Value:

79 %

At concentration:

1 000 other: µg/mL

Cell viability:

94.2%

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

RFI CD86>200 [442E]

Remarks:

RFI of CD86 at all the concentrations tested are less than 150%

Value:

86 %

At concentration:

1 000 other: µg/mL

Cell viability:

93.9%

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Group:

test chemical

Run / experiment:

run/experiment 2

Parameter:

RFI CD86>200 [442E]

Remarks:

RFI of CD86 at all the concentrations tested are less than 150%

Value:

88 %

At concentration:

1 000 other: µg/mL

Cell viability:

95.5%

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Results of the Cell Batch Activation Test Batch 15

Sample	Concentration [µg/mL]	CD86			CD54			Activated	Pass /Fail
		Cell Viability [%]	RFI	Threshold OECD TG 442E	Cell Viability [%]	RFI	Threshold OECD TG 442E	yes/no
DNCB	4 µg/mL	84	245	>150	84	632	>200	yes	pass
NiSO4	100 µg/mL	78	211	>150	82	885	>200	yes	pass
LA	1000 µg/mL	91	74	£150	88	74	£200	no	pass

 Results of the Cell Batch Activation Test Batch 16

Sample	Concentration [µg/mL]	CD86			CD54			Activated	Pass /Fail
		Cell Viability [%]	RFI	Threshold OECD TG 442E	Cell Viability [%]	RFI	Threshold OECD TG 442E	yes/no
DNCB	4 µg/mL	84	219	>150	85	658	>200	yes	pass
NiSO4	100 µg/mL	74	171	>150	83	678	>200	yes	pass
LA	1000 µg/mL	89	70	£150	93	61	£200	no	pass

Results of the Dose Finding Assay

Sample		Concentration applied [µg/mL]	Cell Viability [%]
Medium Control	--	--	92.60
Solvent Control	DMSO	--	92.39
Methy Propyl Ketone	C8	7.81	91.59
	C7	15.63	91.17
	C6	31.25	92.17
	C5	62.50	91.84
	C4	125.00	92.23
	C3	250.00	92.64
	C2	500.00	92.09
	C1	1000.00	92.53
Calculated CV75 [µg/mL]		No CV75

 

CD54 and CD86 Expression Experiment 1

Sample	Conc. [μg/mL]	Cell Viability [%]			Mean Fluorescence Intensity			corrected Mean Fluorescence Intensity		Relative Fluorescence Intensity (RFI)		Ratio Isotype IgG1 to [%]
		CD86	CD54	Isotype IgG1	CD86	CD54	Isotype IgG1	CD86	CD54	CD86	CD54	CD86	CD54
Medium Control	-	93.6	92.7	92.8	2022	720	461	1561	259	122	93	439	156
Solvent Control	0.20%	93.9	94.0	91.6	1697	694	415	1282	279	100	100	409	167
DNCB	4.00	80.6	79.0	78.1	3643	2012	486	3157	1526	246	547	750	414
Methyl Propyl Ketone	1000	93.9	93.6	87.6	1531	673	425	1106	248	86	89	360	158
	833.33	94.2	94.0	92.4	1747	704	436	1311	268	102	96	401	161
	694.44	95.6	93.9	92.9	1642	705	447	1195	258	93	92	367	158
	578.70	93.2	93.3	92.2	1938	713	440	1498	273	117	98	440	162
	482.25	94.2	94.8	93.3	1770	693	445	1325	248	103	89	398	156
	401.88	92.8	94.3	94.4	1810	702	451	1359	251	106	90	401	156
	334.90	91.9	93.0	94.4	1801	693	460	1341	233	105	84	392	151
	279.08	94.0	93.6	85.7	1637	695	461	1176	234	92	84	355	151

CD54 and CD86 Expression Experiment 2

Sample	Conc. [μg/mL]	Cell Viability [%]			Mean Fluorescence Intensity			corrected Mean Fluorescence Intensity		Relative Fluorescence Intensity (RFI)		Ratio Isotype IgG1 to [%]
		CD86	CD54	Isotype IgG1	CD86	CD54	Isotype IgG1	CD86	CD54	CD86	CD54	CD86	CD54
Medium Control	-	96.4	95.6	96.4	1209	545	367	842	178	90	74	329	149
Solvent Control	0.20%	93.6	92.9	94.9	1283	586	345	938	241	100	100	372	170
DNCB	4.0	83.3	83.8	83.8	3893	1651	419	3474	1232	370	511	929	394
Methyl Propyl Ketone	1000.00	95.5	94.2	93.2	1181	543	352	829	191	88	79	336	154
	833.33	94.1	95.5	90.9	1217	545	359	858	186	91	77	339	152
	694.44	94.7	95.2	95.0	1228	534	363	865	171	92	71	338	147
	578.70	94.1	95.3	94.4	1419	564	357	1062	207	113	86	397	158
	482.25	94.4	95.7	93.2	1248	552	350	898	202	96	84	357	158
	401.88	95.0	96.0	95.8	1354	531	363	991	168	106	70	373	146
	334.90	94.7	94.7	95.4	1228	524	363	865	161	92	67	338	144
	279.08	96.0	95.9	95.3	1197	540	372	825	168	88	70	322	145

Acceptance Criteria

Acceptance Criterion	Range	Experiment 1			pass/fail	Experiment 2			pass/fail
cell viability solvent controls [%]	>90	91.6	-	94.0	pass	92.9	-	96.4	pass
number of test dosed with viability >50% CD86	≥4	8			pass	8			pass
number of test dosed with viability >50% CD54	≥4	8			pass	8			pass
number of test dosed with viability >50% IgG1	≥4	8			pass	8			pass
RFI of positive control of CD86	≥150	246			pass	370			pass
RFI of positive control of CD54	≥200	547			pass	511			pass
RFI of solvent control of CD86	<150	82			pass	111			pass
RFI of solvent control of CD54	<200	108			pass	135			pass
MFI ratio CD86/IgG1 for medium control [%]	>105	439			pass	329			pass
MFI ratio CD86/IgG1 for DMSO control [%]	>105	409			pass	372			pass
MFI ratio CD54/IgG1for medium control [%]	>105	156			pass	149			pass
MFI ratio CD54/IgG1for DMSO control [%]	>105	167			pass	170			pass

The in vitrohuman 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.

Prior to the main study the cell batches were checked for its reactivity towards known positive and negative controls and was found to be acceptable for further testing.

In the present study Methyl Propyl Ketone was dissolved in DMSO. For the dose finding assay stock solutions with concentrations ranging from 500 mg/mL to 3.91 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.

Due to a lack of cytotoxicity, no CV75 could be derived. Therefore, the main experiment was performed covering the following concentration steps:

1000, 833.33, 694.44, 578.70, 482.25, 401.88, 334.90, 279.08 µg/mL

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.

No cytotoxic effects were observed for the cells treated with the test item. Relative cell viability at the highest test item concentration was reduced to 93.9% (CD86), 93.6% (CD54) and 87.6% (isotype IgG1 control) in the first experiment and to 95.5% (CD86), 94.2% (CD54) and 93.2% (isotype IgG1 control) in the second experiment.

The expression of the cell surface marker CD86 was not upregulated above the threshold of 150% in any of the experiments. The expression of cell surface marker CD54 was not upregulated above the threshold of 200% in any of the experiments. Therefore, the test item can be considered as non-sensitiser.

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions the test item did not upregulate the expression of the cell surface marker in at least two independent experiment runs. Therefore, the test item might be considered as non-sensitiser.
The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Executive summary:

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.

Prior to the main study the cell batches were checked for its reactivity towards known positive and negative controls and was found to be acceptable for further testing.

In the present study Methyl Propyl Ketone was dissolved in DMSO. For the dose finding assay stock solutions with concentrations ranging from 500 mg/mL to 3.91 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.

Due to a lack of cytotoxicity, no CV75 could be derived. Therefore, the main experiment was performed covering the following concentration steps: 1000, 833.33, 694.44, 578.70, 482.25, 401.88, 334.90, 279.08 µg/mL 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.

No cytotoxic effects were observed for the cells treated with the test item. Relative cell viability at the highest test item concentration was reduced to 93.9% (CD86), 93.6% (CD54) and 87.6% (isotype IgG1 control) in the first experiment and to 95.5% (CD86), 94.2% (CD54) and 93.2% (isotype IgG1 control) in the second experiment.

The expression of the cell surface marker CD86 was not upregulated above the threshold of 150% in any of the experiments. The expression of cell surface marker CD54 was not upregulated above the threshold of 200% in any of the experiments. Therefore, the test item can be considered as non-sensitiser.

Conclusion

In this study under the given conditions the test item didnotupregulate the expression of the cell surface marker in at least two independent experiment runs. Therefore, the test item is considered as non-sensitiser.

The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Reference 3

Endpoint:

skin sensitisation: in vitro

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2022

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 442D (In Vitro Skin Sensitisation: ARE-Nrf2 luciferase KeratinoSens™ test method)

GLP compliance:

yes (incl. QA statement)

Type of study:

ARE-Nrf2 luciferase KeratinoSens™ test method

Justification for non-LLNA method:

The study was conducted due to the requirement to do in vitro testing before in vivo testing

Specific details on test material used for the study:

Name: Methyl Propyl Ketone
Batch No.: TD21033302
CAS No: 107-87-9
Molecular Weight: 86.13 g/mol
Purity: 94.79%
Physical State: liquid
Colour: colourless
Log KOW not specified by the sponsor
Stability: stable
Storage Conditions: ambient
Expiry Date: 01 January 2023
Safety Precautions: The routine hygienic procedures were sufficient to assure personnel health and safety.

Details of test system:

Keratinoses transgenic cell line [442D]

Vehicle / solvent control:

DMSO

Positive control:

cinnamic aldehyde [442D]

Group:

test chemical

Run / experiment:

run/experiment 1

Parameter:

EC 1.5 [442D]

Remarks:

No significant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC1.5 value could be calculated

Value:

1

At concentration:

2 000 other: µM

Cell viability:

106.3

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Remarks:

No significant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC1.5 value could be calculated.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.

Group:

test chemical

Run / experiment:

run/experiment 2

Parameter:

EC 1.5 [442D]

Remarks:

no significant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC1.5 value could be calculated.; Luciferase activity

Value:

1.06

At concentration:

2 000 other: µM

Cell viability:

94.3%

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of skin sensitisation

Remarks:

No significant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC1.5 value could be calculated.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.

Thein vitroKeratinoSens™ 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 the presentstudy Methyl Propyl Ketone was dissolved in DMSO.

Based on a molecular weight of 86.13 g/mol a stock solution of 200 mMwas prepared.

Based on the stock solution a set of twelve master solutions in 100% solvent was prepared by serial dilution using a constant dilution factor of 1:2. These master solutions were diluted 1:100 in cell culturemedium and a stable suspension was formed. Thefollowing concentration range was tested in the assay: 2000.00, 1000.00, 500.00, 250.00, 125.00, 62.50, 31.25, 15.63, 7.81, 3.91, 1.95, 0.98 µM

Cells were incubated with the test item for 48 h at 37°C. After exposure cells were lysed and luciferase activity was assessed by luminescence measurement.

In the first experiment, nosignificant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC_1.5value could be calculated.

In the second experiment,nosignificant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC_1.5value could be calculated.

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.

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions the test item did not induce the luciferase activity in the transgenic KeratinoSens™ cell line in two independent experiment runs. Therefore, the test item can be considered as a non-sensitiser.
The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Executive summary:

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 the presentstudy Methyl Propyl Ketone was dissolved in DMSO. Based on a molecular weight of 86.13 g/mol a stock solution of 200 mM was prepared. Based on the stock solution a set of twelve master solutions in 100% solvent was prepared by serial dilution using a constant dilution factor of 1:2. These master solutions were diluted 1:100 in cell culturemedium and a stable suspension was formed. Thefollowing concentration range was tested in the assay: 2000.00, 1000.00, 500.00, 250.00, 125.00, 62.50, 31.25, 15.63, 7.81, 3.91, 1.95, 0.98 µM Cells were incubated with the test item for 48 h at 37°C. After exposure cells were lysed and luciferase activity was assessed by luminescence measurement. In the first experiment, nosignificant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC_1.5value could be calculated.

In the second experiment,nosignificant luciferase induction > 1.5 was found in the tested concentration range. Therefore, no EC_1.5value could be calculated. 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.

 

In this study under the given conditions the test item did not induce the luciferase activity in the transgenic KeratinoSens™ cell line in two independent experiment runs. Therefore, the test item can be considered as anon-sensitiser. The data generated with this method may be not sufficient to conclude on the absence of skin sensitisation potential of chemicals and should be considered in the context of integrated approach such as IATA.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

No classification is necessary as the trio of studies showed no potential for sensitization.