7-(4-ethyl-1-methyloctyl)quinolin-8-ol

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 08 October 2018 and 11 October 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:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EU Method B40-BIS

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of Inspection: 15 and 16 November 2017; Date of Signature on Certificate: 15 May 2018

Test material

Test material information

Constituent 1

Reference substance name:

7-(4-ethyl-1-methyloctyl)quinolin-8-ol

EC Number:

277-531-1

EC Name:

7-(4-ethyl-1-methyloctyl)quinolin-8-ol

Cas Number:

73545-11-6

Molecular formula:

C20H29NO

IUPAC Name:

7-(5-ethylnonan-2-yl)quinolin-8-ol

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 1702-18-01/O
- Expiration date of the lot/batch: 25 March 2021

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Storage at room temperature (20 ± 5 °C); keep away from light.

In vitro test system

Test system:

human skin model

Source species:

other: reconstituted human epidermis

Cell type:

other: reconstituted human epidermis

Cell source:

other: reconstitued human epidermis

Source strain:

other: N/A

Details on animal used as source of test system:

N/A - reconstitued human epidermis

Justification for test system used:

The test system has been validated as acceptable for this purpose

Vehicle:

unchanged (no vehicle)

Details on test system:

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1°C


REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: One
- Observable damage in the tissue due to washing: None reported
- Modifications to validated SOP: N/A

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 3 hours
- Spectrophotometer: Anthos Reader 2010 Flexi
- Wavelength: 570 nm
- Filter: N/A
- Filter bandwidth: N/A
- Linear OD range of spectrophotometer: Not reported


NUMBER OF REPLICATE TISSUES: 2

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE N/A


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



FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: Pass (2.027 +/- 0.095)
- Barrier function: Pass (5.11 hours)
- Contamination: Pass (Sterile)

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 µL
- Concentration (if solution): N/A

VEHICLE
N/A

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL
- Concentration (if solution): N/A

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL
- Concentration (if solution): 8M

Duration of treatment / exposure:

3 minutes and 1 hour

Duration of post-treatment incubation (if applicable):

3 hours

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Experiment 1 - 3 min incubation

Value:

102.4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Experiment 2 - 1 hour incubation

Value:

102.1

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: None reported
- Direct-MTT reduction: No
- Colour interference with MTT: No

DEMONSTRATION OF TECHNICAL PROFICIENCY: Demonstrated. The twelve proficiency substances were correctly classified.

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: Yes
- Range of historical values if different from the ones specified in the test guideline: N/A

Any other information on results incl. tables

Measured Values

As blank, the optical density of isopropanol was measured in 12 wells of the 96-well-plate. The measured values and their mean are given in the following table:

Absorbance values blank isopropanol (OD 570 nm)

Replicate	1	2	3	4	5	6	Mean 0.038
Absorbance	0.040	0.039	0.039	0.039	0.038	0.038
Replicate	7	8	9	10	11	12
Absorbance	0.040	0.038	0.037	0.038	0.038	0.037

The absorbance values of negative control, test item and positive control are given in the following table:

Absorbance Values (OD 570 nm)

Incubation	Negative Control		Test Item		Positive Control
	Tissue 1	Tissue 2	Tissue 1	Tissue 2	Tissue 1	Tissue 2
3 min	1.682	1.738	1.709	1.781	0.415	0.439
	1.691	1.684	1.715	1.748	0.411	0.439
	1.688	1.677	1.709	1.733	0.413	0.438
1 h	1.578	1.570	1.658	1.555	0.250	0.258
	1.546	1.563	1.630	1.539	0.250	0.257
	1.541	1.557	1.630	1.536	0.249	0.258

 

From the measured absorbances, the mean absorbance of isopropanol (given in table 8.1-a) was subtracted. The corrected mean and relative standard deviation (RSD) of the two tissues were also calculated.

Mean Absorbance Values of the 3 Minutes Experiment

Designation	Negative Control	Test Item	Positive Control
Mean – blank (tissue 1)	1.649	1.673	0.375
Mean – blank (tissue 2)	1.661	1.716	0.400
Mean of the two tissues	1.655	1.694	0.387
RSD	0.5%	1.8%	4.7%

Mean Absorbance Values of the 1 h Experiment

Designation	Negative Control	Test Item	Positive Control
Mean – blank (tissue 1)	1.517	1.601	0.211
Mean – blank (tissue 2)	1.525	1.505	0.219
Mean of the two tissues	1.521	1.553	0.215
RSD	0.4%	4.4%	2.6%

Comparison of Tissue Viability

For the test item and the positive control, the following percentage values of mean tissue viability were calculated in comparison to the mean of the negative controls:

% Tissue Viability

Test Item	Positive Control	Incubation
102.4%	23.4%	3 min
102.1%	14.2%	1 h

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item is considered non-corrosive to skin.
After 3 minutes treatment, the mean value of relative tissue viability of the test item was 102.4%. This value is well above the threshold for corrosivity (50%). After 1 hour treatment the mean value of relative tissue viability of the test item was 102.1%. This value is well above the threshold for corrosivity (15%).

The values of the negative control met the required acceptability criterion of mean OD ≥ 0.8 and ≤ 2.8 for both treatment intervals, thus showing the quality of the tissues.
The positive control has met the validity criterion too, thus ensuring the validity of the test system.

For these reasons, the result of the test is considered valid.

Executive summary:

One valid experiment was performed.

Two tissues of the human skin model EpiDerm^TMwere treated with the test itemfor 3 minutes and 1 hour, respectively. The test item was applied to each tissue and spread to match the tissue size.

Demineralised water was used as negative control, 8 M KOH was used as positive control.

After treatment, the respective substance was rinsed from the tissues. Then, cell viability of the tissues was evaluated by addition of MTT, which can be reduced to a blue formazan. Formazan production was evaluated by measuring the optical density (OD) of the resulting solution.

 

After treatment with the negative control, the absorbance values were within the required acceptability criterion of mean OD ≥ 0.8 and ≤ 2.8 for both treatment intervals thus showing the quality of the tissues. The OD was 1.7 (3 minutes experiment) and 1.5 (1 hour experiment).

The positive control showed clear corrosive effects for both treatment intervals. The mean relative tissue viability value was reduced to 14.2% for the 1 hour treatment.

After 3 minutes treatment with the test item, the mean value of relative tissue viability was increased to 102.4%. This value is above the threshold for corrosion potential (50%). After 1 hour treatment, mean value of relative tissue viability was increased to 102.1%. This value, too, is above the threshold for corrosion potential (15%).

 

Therefore, the test item7-(4-ethyl-1-methyloctyl)quinolin-8-olis considered non-corrosive to skin in the Reconstructed Human Epidermis (RHE) Test Method.