1-Ethyl-3-methylimidazolium benzoate

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2012-07-24 to 2012-09-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

2004-04-13

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-Ethyl-3-methylimidazolium benzoate

EC Number:

695-723-7

Cas Number:

150999-33-0

Molecular formula:

C13H16N2O2

IUPAC Name:

1-Ethyl-3-methylimidazolium benzoate

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Batch No.of test material: 10361/11/203

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

Based on the results of ECVAM (European Center for Validation of Alternative Methods) funded validation studies, it was concluded by the ECVAM Scientific Advisory Committee that the EpiDerm™ human epidermis model is suitable to be used for distinguishing between corrosive and non-corrosive chemicals (ECVAM: ESAC statement on the application of the EpidermTM human skin model for skin corrosivity testing of 14-15 Mar 2000) as well as between irritant and non-irritant chemicals (ECVAM: ESAC statement on the scientific validity of in-vitro tests for skin irritation testing of 5 Nov 2008).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: Epi-200, MatTek In Vitro Life Science Laboratories, Bratislava, Slovakia

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during exposure: 37 °C / room temperature
- Temperature of post-treatment incubation: 37 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Washing steps: with PBS, 3 min or 1 h after start of exposure and after incubation.
- Observable damage in the tissue due to washing: No

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1.0 mg / mL
- Incubation time: 55 - 65 min
- Spectrophotometer: SunriseTM Absorbance Reader
- Wavelength: 570 nm without reference filter

NUMBER OF REPLICATE TISSUES: 2

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 50 %, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15 %.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is greater than or equal to 15 %.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 50 µL

NEGATIVE CONTROL
- Amount applied: 50 µL

POSITIVE CONTROL
- Amount applied: 50 µL
- Concentration: 8-n potassium hydroxide solution

Duration of treatment / exposure:

3 min or 1 h

Duration of post-treatment incubation (if applicable):

3 h

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 min exposure

Value:

107

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 h exposure

Value:

45

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes
- Acceptance criteria met for variability between replicate measurements: The value for inter-tissue variability of the test substance for the exposure period of 1 hour is about 0.34 and therefore out of the acceptance range. Since all other quality criteria of the test were met and the viability values of both tissues are well above the cut off for skin corrosion, this deviation is not considered to adversely affect the result of this study.

Any other information on results incl. tables

		Exposure: 3 min			Exposure: 1 hour
Test substance		Tissue 1	Tissue 2	Mean	Tissue 1	Tissue 2	Mean
NC	Mean OD570	2.109	2.079	2.094	2.113	2.154	2.134
	Viability [% of NC]	100.7	99.3	100	99.0	101.0	100
Test substance	Mean OD570	2.239	2.249	2.244	1.124	0.785	0.954
	Viability [% of NC]	106.9	107.4	107	52.7	36.8	45
PC	Mean OD570	0.486	0.382	0.434	0.047	0.038	0.042
	Viability [% of NC]	23.2	18.3	21	2.2	1.8	2

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met