reaction mass of 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one and 1-(1,2,3,4,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one and 1-(1,2,3,5,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 June - 26 July 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Two independent tests were run which are combined in the present record.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline 439; In vitro skin irritation: Reconstructed human epidermis method

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

1

Reference substance name:

Reaction Mass of 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one and 1-(1,2,3,4,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one and 1-(1,2,3,5,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

EC Number:

915-730-3

Molecular formula:

C16H26O

IUPAC Name:

Reaction Mass of 1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one and 1-(1,2,3,4,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one and 1-(1,2,3,5,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

Constituent 1

Reference substance name:

1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

EC Number:

259-174-3

EC Name:

1-(1,2,3,4,5,6,7,8-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

Cas Number:

54464-57-2

Molecular formula:

C16H26O

IUPAC Name:

1-(2,3,8,8-tetramethyl-1,2,3,4,5,6,7,8-octahydronaphthalen-2-yl)ethanone

Constituent 2

Reference substance name:

1-(1,2,3,5,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

EC Number:

268-978-3

EC Name:

1-(1,2,3,5,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

Cas Number:

68155-66-8

Molecular formula:

C16H26O

IUPAC Name:

1-(2,3,8,8-tetramethyl-1,2,3,5,6,7,8,8a-octahydronaphthalen-2-yl)ethanone

Constituent 3

Reference substance name:

1-(1,2,3,4,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

EC Number:

268-979-9

EC Name:

1-(1,2,3,4,6,7,8,8a-octahydro-2,3,8,8-tetramethyl-2-naphthyl)ethan-1-one

Cas Number:

68155-67-9

Molecular formula:

C16H26O

IUPAC Name:

1-(2,3,8,8-tetramethyl-1,2,3,4,6,7,8,8a-octahydronaphthalen-2-yl)ethanone

Test material form:

liquid

Test animals

Species:

other: EPISKIN human epidermis skin constructs.

Strain:

other: Commercial test kit

Details on test animals or test system and environmental conditions:

Not applicable

Test system

Type of coverage:

not specified

Preparation of test site:

not specified

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 µL
- Concentration (if solution): 100%

Duration of treatment / exposure:

15 minutes

Observation period:

not applicable

Number of animals:

not applicable

Details on study design:

See any other information below

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

other: other: Tissue viability as percentage of mean OD negative control

Run / experiment:

1

Value:

59.1

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

other: other: Tissue viability as percentage of mean OD negative control

Run / experiment:

2

Value:

41.6

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 3

Irritation / corrosion parameter:

other: other: Tissue viability as percentage of mean OD negative control

Run / experiment:

3

Value:

45.5

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 4

Irritation / corrosion parameter:

other: other: Tissue viability as percentage of mean OD negative control

Run / experiment:

Mean of 3

Value:

48.8

Remarks on result:

other:

Remarks:

Borderline result: 45-55%, but substance is considered an irritant

Results 5

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

4

Value:

58.2

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 6

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

5

Value:

57.2

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 7

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

6

Value:

49.2

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 8

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

mean of 3

Value:

55

Remarks on result:

other:

Remarks:

Less irritancy is seen compared to the first test but final conclusion is that the substance is an irritant

Any other information on results incl. tables

Table 1 EPISKIN Results Repeat Study (key study)

 

Sample	Tissue viability as percentage of mean OD negative control				Prediction MTT endpoint
	Replicate Tissues			Mean ± SD
	a	b	c
Negative Control	101.6	99.3	99.1	100.0 ± 1.4	Non-irritant
Positive control	19.3	28.4	12.1	19.9 ± 8.2	Irritant
IFF TM 09 -221	59.1	41.6	45.5	48.8 ± 9.2	Irritant

As the mean tissue viability was less than 50% of the negative control value in the repeat study (48.8% +/- 9.2%), it was decided to classify the test-substance conservatively as Irritant R38 (EU DSD) / Irritant H315 (EU CLP) and not to run another repeat study.

Table 2 EPISKIN Results Original Study

 

Sample	Tissue viability as percentage of mean OD negative control				Prediction MTT endpoint
	Replicate Tissues			Mean ± SD
	a	b	c
Negative Control	114.5	87.0	98.5	100.0 ± 13.8	Not applicable
Positive control	10.8	11.3	13.9	12.0 ± 1.7	Irritant
IFF TM 09 -221	58.2	57.2	49.5	55.0 ± 4.8	Non-irritant

As the tissue viability of 55.0% was a borderline result in the range 45-55%, it was proposed to repeat the test in a further study, although the OECD guideline does not have an absolute requirement for a repeat test.

Methodology

The mean Optical Density (OD) for the 6 replicate blanks was subtracted from the individual substance and control tissues OD.

The viability of each tissue was expressed as a percentage of the mean negative control value.

Assay acceptance criteria

The OD from the negative control tissue in the MTT assay is an indicator of tissue viability after the shipping and storage procedure and under the specific conditions of the assay. The mean absorbance of the triplicate negative control values should be >=0.6 and the Standard Deviation (SD) value of the % viability should be ≤18. The OD of the positive control is an indicator of the sensitivity of the tissues. The mean viability should be ≤30% of the negative control and the SD ≤18.

Data interpretation - Prediction model

If the mean tissue viability was less than 50% of the negative control value, the sample was classed as Irritant

If the mean tissue viability was greater than 50% of the negative control value, the sample was classed as non-irritant.

Applicant's summary and conclusion

Interpretation of results:

other: skin irritant Cat 2

Remarks:

according to EU CLP (EC 1272/2008 and its amendments)

Conclusions:

Two skin irritation test showed tissue viability between 45 and 55%. To be conservative the substance is considered an irritant to the skin Cat 2.

Executive summary:

An in vitro skin irritation study was performed in accordance with OECD 439. As the tissue viability presented borderline result in the range 45 -55%, with a mean of 48% tissue viability. In a second test the mean tissue viability was 55%. A conservative approach has been taken and result in the substance being a skin irritant.