2-heptadecyl-1H-imidazole

Eye irritation

Administrative data

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 May 2017 - 11 Jan 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 492 (Reconstructed Human Cornea-like Epithelium (RhCE) Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage)

Version / remarks:

28 Jul 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Landesleitstelle Bayern, Bayerisches Landesamt für Gesundheit, Schwabach, Deutschland

Test material

Test material information

1

Reference substance name:

2-heptadecyl-1H-imidazole

EC Number:

245-589-7

EC Name:

2-heptadecyl-1H-imidazole

Cas Number:

23328-87-2

Molecular formula:

C20H38N2

IUPAC Name:

2-heptadecyl-1H-imidazole

Test animals / tissue source

Species:

human

Details on test animals or tissues and environmental conditions:

- reconstructed human cornea-like epithelium (RhCE) tissue construct, EpiOcular™ (OCL-200 EIT)
- Lot number: 27015
- Keratinocyte strain: 4F1188
- no biological contaminants (virus, bacteria, yeast or fungi) detected
- Acceptance criteria for tissue viability met: 1.958 ± 0.065 (Acceptance criteria: OD (540-570 nm) [1.1 - 3.0])
- Acceptance criteria for Barrier function met: 25.64 min (Acceptance criteria: ET-50 [12.2 - 37.5])

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 50 mg

NEGATIVE CONTROL
- Amount(s) applied: 50 µL
- Lot/batch no.: Sigma, RNBF7110

POSITIVE CONTROL
- Amount(s) applied: 50 µL
- Lot/batch no.: Merck, S6943111

Duration of treatment / exposure:

6 ± 0.25 h

Duration of post- treatment incubation (in vitro):

25 ± 2 min (post-soak plate)
18 ± 0.25 h (post-treatment plate)

Number of animals or in vitro replicates:

duplicates for each treatment and control group; from each tissue, 2 absorbance measurements after 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) incubation were performed

Details on study design:

- RhCE tissue construct used, including batch number: EpiOcular™, Test Kit name: OCL-200-EIT (MatTek), Lot number: 27015
- Duration and temperature of exposure, post-exposure immersion and post-exposure incubation periods: exposure: 6 ± 0.25 h at 37 ± 1°C, post exposure: 25 ± 2 min at room temperature (post-soak plate), 18 ± 0.25 h (post-treatment plate) at 37 ± 1°C
- Indication of controls used for direct MTT-reducers and/or colouring test chemicals: The ability of the test substance to directly reduce MTT and to change the color of the MTT medium was assessed in a pre-experiment. Since the MTT solution colour did not change, the test substance is not presumed to have reduced the MTT. Furthermore, mixture of the test substance with distilled water or isopropanol showed no colouring potential as compared to the solvent.
- Number of tissue replicates used per test chemical and controls: 2
- Wavelength: 570 nm ± 30 nm
- Spectrophotometer: plate spectrophotometer
- Description of evaluation criteria used: The test substance is considered to be not irritating to eye if the tissue viability is > 60%. The test substance is considered to be irritating to eye if the tissue viability is ≤ 60%.
- Positive and negative control means and acceptance ranges: The test meets acceptance criteria if: mean absolute OD570 of the negative control is > 0.8 and < 2.5, mean relative tissue viability of the positive control is < 50%
- Acceptable variability between tissue replicates for positive and negative controls and for the test substance: Differences of two tissue cell viabilities in each treatment group are < 20%

Results and discussion

In vitro

Results

Irritation parameter:

other: % tissue viability mean value of 2 tissues

Value:

109.6

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

OTHER EFFECTS:
The mixture of the test substance with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) medium showed no reduction of MTT as compared to the solvent. The mixture did not turn blue/purple.
The mixture of the test substance with distilled water or isopropanol showed no colouring as compared to the solvent.

ACCEPTANCE OF RESULTS:
The controls confirmed the validity of the study.
The mean absolute OD570 of the two negative control tissues was > 0.8 and < 2.5 (1.776).
The mean relative tissue viability (% negative control) of the positive control was < 50% (19.1%).
The inter tissue difference of replicate tissues of all dose groups was < 20% (6.3%).

Any other information on results incl. tables

Table 2: Summary of Results

Name	Negative Control		Positive Control		Test Substance
Tissue	1	2	1	2	1	2
OD570 values (blank-corrected)	1.818	1.737	0.312	0.365	1.939	1.902
	1.847	1.704	0.328	0.356	2.016	1.929
Mean of the duplicates	1.833	1.720	0.320	0.360	1.978	1.915
Mean OD	1.776*		0.340		1.946
Mean sd OD	0.07		0.02		0.05
Tissue viability [%]	103.2	96.8	18.0	20.3	111.3	107.8
Relative tissue viability difference [%]^***	6.3		2.3		3.5
Mean tissue viability [%]	100.0		19.1**		109.6

*         Corrected mean OD570 of the negative control corresponds to 100% absolute tissue viability

**        mean relative tissue viability of the positive control is < 50%

***       relative tissue viability difference of replicate tissues is < 20%.

OD = optical density

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria not met, no classification required according to Regulation(EC) No. 1272/2008

Conclusions:

Under the conditions of the RhCE test method the test substance did not show irritant properties.
CLP: not classified