2,4,6-trimethylcyclohex-3-ene-1-methanol

Endpoint summary

Description of key information

Skin corrosion: No corrosive effects are expected based structural grounds and the 100% application in the LLNA test, not showing corrosive effects.

Skin irritation (OECD TG 439): Irritating
Eye irritation and severe damage (OECD TG 405): Irritating

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 March, 2016 - 14 March, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Version / remarks:

adopted 28 July 2015

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

Amended by EC No. 640/2012 OJ No. L193, 20 July 2012

Deviations:

no

GLP compliance:

yes

Test system:

human skin model

Source species:

human

Cell type:

other: epidermal keratinocytes

Cell source:

other: SkinEthic Laboratories, Lyon, France.

Source strain:

other: Not applicable

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN Small ModelTM, 0.38 cm^2
- Tissue batch number: 16-EKIN-010
- Twenty five μL of the undiluted test substance was added into 12-well plates on top of the skin tissues.
- The test item was applied topically to the corresponding tissues ensuring uniform covering.

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 36.4 - 37.2°C

PRE-TEST PROCEDURE:
Assessment of Direct Test Item Reduction of MTT
MTT Salt Metabolism, Cell Viability Assay
The MTT assay, a colorimetric method of determining cell viability, is based on reduction of the yellow te trazolium salt (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to a blue formazan salt by mitochondrial succinate dehydrogenase in viable cells. One limitation of the assay is possible interference of the test item with MTT. A test item may directly reduce MTT, thus mimicking dehydrogenase activity of thecellular mitochondria. This property of the test item is only a problem, if at the time of the MTT test (after rinsing) there are still sufficient amounts of the test item present on or in the tissues. In this case, the true metabolic MTT reduction and the false direct MTT reduction can be differentiated and quantified.
Test for Direct MTT Reduction + colour interference:
ISOCYCLOGERANIOL was checked for possible direct MTT reduction before the study was started. To assess the ability of the test item to reduce MTT, 25 μL of the test item was added to 2 mL MTT solution (0.3 mg/ml in PBS). The mixture was incubated for 3 hours at 37°C. A negative control, sterile Milli-Q water was tested concurrently. At the end of the incubation period a colour check was performed.

PRE-INCUBATION:
On the day of receipt the tissues were transferred to 12-well plates and preincubated with prewarmed Maintenance Medium for approximately 23 hours at 37°C. Maintenance medium and Assay medium were supplied by Skinethic Laboratories, Lyon,
France.

APPLICATION/TREATMENT OF TEST SUBSTANCE:
The test was performed on a total of 3 tissues per test item together with negative and positive controls. Twenty five μl of the undiluted test item was added into 12-well plates on top of the skin tissues. Three tissues were treated with 25 μL PBS (negative control) and 3 tissues with 25 μL 5% SDS (positive control) respectively. The positive control was re-spread after 7 minutes contact time. After the exposure period of 15 ± 0.5 minutes at room temperature, the tissues were washed with phosphate buffered saline to remove residual test item. After rinsing, the cell culture inserts were each dried carefully and moved to a new well on 2 mL pre-warmed maintenance medium until all tissues were dosed and rinsed. Subsequently the skin tissues were incubated for 42 hours at 37°C.

CELL VIABILITY MEASUREMENT:
After incubation, cell culture inserts were dried carefully to remove excess medium and were transferred into a 12-wells plate prefilled with 2 ml MTT-solution (0.3 mg/ml in PBS). The tissues were incubated for 3 h at 37°C. After incubation the tissues were placed on blotting paper to dry the tissues. Total biopsy was made by using a biopsy punch. Epidermis was separated from the collagen matrix and both parts were placed in prelabeled microtubes and extracted with 500 μl isopropanol (Merck, Darmstadt, Germany). Tubes were stored refrigerated and protected from light for approximately
69 hours. The amount of extracted formazan was determined spectrophotometrically at 570 nm in duplicate with the TECAN Infinite® M200 Pro Plate Reader.
Cell viability was calculated for each tissue as a percentage of the mean of the negative control tissues. Skin irritation potential of the test item was classified according to remaining cell viability following exposure of the test item.

DECISION CRITERIA
- A test substance is considered irritant in the skin irritation test if: The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test substance and 42 hours of post incubation is ≤ 50% of the mean viability of the negative controls.
- A test substance is considered non-irritant in the in vitro skin irritation test if: The relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test substance and 42 hours of post incubation is > 50% of the mean viability of the negative controls.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

Test material
- Applied volume: 25 μL

Duration of treatment / exposure:

15-Minute exposure period and 42 hours post-exposure incubation period.

Number of replicates:

A total of 9 tissues were used: Triplicate tissues were treated with: test substance, positive control or negative control.

Irritation / corrosion parameter:

other: relative mean viability

Value:

12

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: The relative mean tissue viability compared to the negative control tissues (100%).

Other effects / acceptance of results:

Direct MTT Reduction:
ISOCYCLOGERANIOL was checked for colour interference in aqueous conditions and possible direct MTT reduction by adding the test item to MTT medium. Because no colour changes were observed it was concluded that ISOCYCLOGERANIOL did not interact with the MTT endpoint.

Test Item, Positive Control Item and Negative Control Item:
The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with Peomosa compared to the negative control tissues was 12%.

Quality Criteria:
The positive control had a mean cell relative viability compared to the negative control after 15 ± 0.5 minutes exposure of 19%. The absolute mean OD570 of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was less than 9% for the negative control, positive control and the test item, indicating that the test system functioned properly.

Mean OD570 Values and Percentage Viabilities for the Negative Control Item, Positive Control Item and Test Item:

Item	OD570 of tissues	Mean OD562 of triplicate tissues	± SD of OD570	Relative individual tissue viability (%)	Relative mean viability (%)
Negative Control Item	1.143	1.176	0.096		100
	1.102
	1.284
Positive Control Item	0.320	0.227	0.081	28	19
	0.186			17
	0.176			14
Test Item	0.156	0.227	0.081	14	12
	0.146			13
	0.133			10

SD = Standard deviation

*The mean viability of the negative control tissues is set at 100 %

Interpretation of results:

other: a skin irritant

Remarks:

According to Regulation (EC) No. 1272/2008 and its amendments.

Conclusions:

The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with the substance compared to the negative control tissues was 12%. Since the mean relative tissue viability for the substance was below 50%, the substance is considered to be irritant.

Executive summary:

The possible skin irritation potential of the substance was tested in vitro using a human skin model through topical application for 15 minutes. The study procedures described in this report were according to OECD TG 439 guideline and GLP principles. Skin tissue was treated by topical application of 25 μL undiluted test substance. After 42 hours incubation period, determination of the cytotoxic (irritancy) effect was performed. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) MTT at the end of treatment. Skin irritation is expressed as the remaining cell viability after exposure to the test substance. Reliable negative and positive controls were included. The positive control had a mean cell viability of 19% after 15 minutes exposure. The standard deviation value of the percentage viability of three tissues treated identically was less than 9%, indicating that the test system functioned properly. The relative mean tissue viability obtained after 15 minutes treatment with the substance compared to the negative control tissue was 12%. Since the mean relative tissue viability for Isocyclogeraniol was below 50% after 15 minutes treatment the substance is considered to be irritant and the substance shall be classified as a skin irritant.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February 4, 1986 - February 19, 1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The test was performed before the REACH regulation came into force requesting in vitro studies. The results are used for read across to Isocyclogeraniol.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

1981

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

- Source: Nottingham University, School of Agriculture, Sutton Bonington, Leicestershire, U.K.
- Age at study initiation: 12-16 weeks
- Weight at study initiation: Body weights were 2.65-3.14 kg
- Housing: Individually
- Diet: Free access to food (Rabbit Diet, A.W. Tindall Limited, Holbeach, Lincolnshire, U.K.)
- Water: Free access to drinking water
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS (set to maintain)
- Temperature (°C): 18-20
- Humidity (%): 45-55
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

unchanged (no vehicle)

Controls:

other: One eye of each animal remained untreated and served as the reference control.

Amount / concentration applied:

Amount applied: 0.1 mL

Duration of treatment / exposure:

Single instillation on Day 1

Observation period (in vivo):

14 days

Number of animals or in vitro replicates:

3 (sex unknown)

Details on study design:

STUDY DESIGN
The test material was applied undiluted in 3 animals.

TREATMENT
In accordance with OECD 405 (1981). The test substance is placed in the conjunctival sac of one eye of each animal after gently pulling the lower lid away from the eyeball. The lids are then gently held together for about one second. The other eye serves at control.

REMOVAL OF TEST SUBSTANCE
-Washing: No

OBSERVATIONS
- Irritation:
The eyes of each animal were examined approximately 1, 24, 48 and 72 hours and 7 and 14 days after instillation of the test substance.
The irritation scores and a description of all other (local) effects were recorded. The irritation was assessed according to OECD 405 (1981).
Examination of the eye was facilitated by use if a standard ophthalmoscope.

Irritation parameter:

other:

Vehicle controls validity:

other: other information is presented

Remarks on result:

other: Other information is presented

Irritation parameter:

cornea opacity score

Remarks:

Degree

Basis:

animal: #1 and #3 (mean)

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 14 days

Remarks:

But some circum corneal vacualisation was seen in animal 3

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

animal: #2 (mean)

Time point:

24/48/72 h

Score:

2.33

Max. score:

4

Reversibility:

not fully reversible within: 14 days

Irritation parameter:

iris score

Basis:

animal: #1 (mean)

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible

Irritation parameter:

iris score

Basis:

animal: #2 and #3 (mean)

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 14 days

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

animal: #1 and #3 (mean)

Time point:

24/48/72 h

Score:

2.33

Max. score:

3

Reversibility:

fully reversible within: 7 days

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

animal: #2 (mean)

Time point:

24/48/72 h

Score:

2.66

Max. score:

3

Reversibility:

fully reversible within: 14 days

Irritation parameter:

chemosis score

Basis:

animal: #1 (mean)

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritation parameter:

chemosis score

Basis:

animal: #2 (mean)

Time point:

24/48/72 h

Score:

2.33

Max. score:

4

Reversibility:

fully reversible within: 14 days

Irritation parameter:

chemosis score

Basis:

animal: #3 (mean)

Time point:

24/48/72 h

Score:

1.66

Max. score:

4

Reversibility:

fully reversible within: 7 days

Irritant / corrosive response data:

A dulling of the normal lustre of the corneal surface was noted in all treated eyes one hour after treatment. Circumcorneal vascularisation was noted in two of the three treated eyes on day 14 (animal 2 and 3); the remaining treated eye showed a dulling of the normal lustre of the corneal surface at day 7 (animal 1). A small area of opalescent opacity was noted in one treated eye on day 14.
Iridial inflammation was noted in all treated eyes one hour after treatment and in one treated eye on day 7.
Conjunctivitis was noted in all treated eyes one hour after treatment and in one eye on day 7.

Interpretation of results:

other: Irreversible effects on the eye, cat. 1.

Remarks:

According to Regulation (EC) No. 1272/2008 and its amendments

Conclusions:

In an eye irritation study with rabbits, performed according to OECD TG 405 (1981) and GLP principles, irritation was observed in all animals resulting in scores that need classification.
Most test results indicated a Cat 2 classification: All three animals showed conjunctivae redness ≥2 and in 2 of 3 animals conjunctivae oedema (chemosis) ≥2. Iridial inflammation (score = 1) was noted in two animals. All animals showed opacity ≥1. Observed effects were reversible in all animals within 7 to 14 days
However, because in one animal cornea opacity effects (score 3 and circumcorneal vascularisation on day 14) was seen and the not expected reversibility the substance is classified “irreversible effects on the eye, cat. 1” according to Regulation (EC) No. 1272/2008 and Category 1 Serious eye damage according to GHS.

Executive summary:

The substance was tested in an eye irritation test in rabbits according to OECD TG 405 test guideline and in compliance with GLP principles. The eyes of three rabbits were exposed to 0.1 mL of the test substance and observations were made up to 14 days after installation. All three animals showed conjunctivae redness ≥2 and in 2 of 3 animals conjunctivae oedema (chemosis) ≥2. Iridial inflammation (score = 1) was noted in two animals. All animals showed opacity ≥1. Observed effects were reversible in all animals within 7 to 14 days except for opacity effects in one animal (score 3 and circumcorneal vascularisation on day 14). Based on the test results, the substance is classified “irreversible effects on the eye.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Additional information

Skin corrosion:

The substance is not considered corrosive because no corrosive functional groups are present: the substance is an alkyl alcohol. The methyl group attached to the double bond is not a corrosive alert either. In addition, no corrosive effects were seen in the LLNA test up to 100%.

In vitro skin irritation test:

The possible skin irritation potential of the substance was tested in vitro using a human skin model through topical application for 15 minutes. The study procedures described in this report were according to OECD TG 439 guideline and GLP principles. Skin tissue was treated by topical application of 25 μL undiluted test substance. After 42 hours incubation period, determination of the cytotoxic (irritancy) effect was performed. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) MTT at the end of treatment. Skin irritation is expressed as the remaining cell viability after exposure to the test substance. Reliable negative and positive controls were included. The positive control had a mean cell viability of 19% after 15 minutes exposure. The standard deviation value of the percentage viability of three tissues treated identically was less than 9%, indicating that the test system functioned properly. The relative mean tissue viability obtained after 15 minutes treatment with the substance compared to the negative control tissue was 12%. Since the mean relative tissue viability for Isocyclogeraniol was below 50% after 15 minutes treatment the substance is considered to be irritant and the substance shall be classified as a skinirritant.

Eye irritation OECD TG 405:

The substance was tested in an eye irritation test in rabbits according to OECD TG 405 test guideline and in compliance with GLP principles. The eyes of three rabbits were exposed to 0.1 mL of the test substance and observations were made up to 14 days after installation. All three animals showed conjunctivae redness ≥2 and in 2 of 3 animals conjunctivae oedema (chemosis) ≥2. Iridial inflammation (score = 1) was noted in two animals. All animals showed opacity ≥1. Observed effects were reversible in all animals within 7 to 14 days except for opacity effects in one animal (score 3 and circumcorneal vascularisation on day 14). Based on the test results, the substance is classified “irreversible effects on the eye.

Justification for classification or non-classification

Based on the positive result in the skin irritation test with the substance and the positive result in the eye irritation test with the read-across substance, the substance needs to be classified as a skin and eye irritant. According to EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and GHS this results in skin irritation category 2, H315: Causes skin irritation and serious eye damage category 1, H318: Causes serious eye damage.