Farnesol

Endpoint summary

Description of key information

In an LLNA assay conducted in accordance with OECD 429, Stimulation Indices (SI) of 2.8, 4.7, and 17.6 were determined with the test item at concentrations of 5, 10 and 25% (w/v) in acetone:olive oil (4:1). The EC3 value calculated was 5.5 % (w/v). The test item was found to be a skin sensitiser.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

2002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation:8 - 12 weeks (beginning of acclimatisation)
- Housing: Makrolon Type 1 with wire mesh top, single caging
- Diet: Pelleted standard diet, ad libitum
- Water: Tap water, ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 30 to 70%
- Photoperiod (hrs dark / hrs light): 12 hour photoperiod with artificial light

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

5%, 10% and 25%

No. of animals per dose:

4

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA assay
- Criteria used to consider a positive response: Stimulation Index >3

TREATMENT PREPARATION AND ADMINISTRATION:
Each test group of mice was treated by topical (epidermal) application to the dorsal surface of each ear lobe (left and right) with different test item concentrations of 5, 10 and 25% (w/v) in acetone:olive oil (4:1). The application volume, 25 ul, was spread over the entire dorsal surface (0 - 8 mm) of each ear lobe once daily for three consecutive days. A further group of mice was treated with an equivalent volume of the relevant vehicle alone (control animals). A hair dryer was used to dry the ear's surface as quickly as possible to avoid loss of test item applied.

Five days after the first topical application, all mice were administered with 250 uL of 78.9 uCi/mL 3HTdR (corresponding to 19.73 uCi 3HTdR per mouse) by intravenous injection via a tail vein. Approximately five hours after treatment with 3HTdR all mice were euthanised by intraperitoneal injection of Na-thiopental. The draining lymph nodes were rapidly excised and pooled for each experimental group (8 nodes per group). The level of 3HTdR incorporation was measured on a ß-scintillation counter, expressed as the number of radioactive disintegrations per minute (DPM).

Mortality, bodyweights and clinical signs of toxicity were also recorded during the study.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

A statistical analysis was conducted for assessment of the dose-response relationship and the EC3 value was calculated. EC3 is the estimated concentration of the test item required to produce a 3-fold increase in draining lymph node cell proliferative activity.

Positive control results:

The validation/positive control study was performed with alpha-Hexylcinnamaldehyde in acetone:olive oil, 4:1 (v/v) using CBA/CaOlaHsd mice in a separate study (April 2004). Stimulation indices at 5, 10 and 25 % (w/v) positive control concentrations were determined to be 1.9, 6.1 and 11.5, respectively. An EC3 pf 6.3% (w/v) was calculated.

Key result

Parameter:

EC3

Value:

> 3

Parameter:

SI

Value:

3.8

Test group / Remarks:

5% test item (w/v)

Parameter:

SI

Value:

6.7

Test group / Remarks:

10% test item (w/v)

Parameter:

SI

Value:

12.7

Test group / Remarks:

25% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

771.6

Test group / Remarks:

5% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

1 359.3

Test group / Remarks:

10% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

2 568.9

Test group / Remarks:

25% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

202.2

Test group / Remarks:

Control

Cellular proliferation data / Observations:

No mortality was observed during the study and the test item had no significant effect on bodyweight. The ears of all animals treated with the highest concentration (25%) were slightly red after the second treatment and all four treated animals had red inflamed ears after the third treatment. Two animals treated with 10% test item had slightly red ears after the last application. No systemic findings were, however, observed during the study period.

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

Stimulation indices at 5, 10 and 25 % (w/v) test item concentrations were determined to be 3.8, 6.7 and 12.7, respectively. The EC3 could not be calculated as the SI of lowest concentration tested was above 3.

Executive summary:

The skin sensitising potential of the test item was assessed by local lymph node assay (LLNA). Female mice were treated daily with the test item at concentrations of 5, 10 and 25% (w/v) in acetone:olive oil (4:1) by topical application to the dorsum of each ear lobe for three consecutive days. A control group of four mice was treated with the vehicle only. Five days after the first topical application the mice were injected intravenously into a tail vein with radio-labelled thymidine. Approximately five hours after intravenous injection, the mice were sacrificed, the draining auricular lymph nodes excised and pooled per group. The proliferative capacity of pooled lymph node cells was determined by the incorporation of 3H-methyl thymidine measured in a beta-scintillation counter. No mortality or adverse effects on bodyweight were observed during the study period. Redness of the ear was observed at higher concentrations and with repeat dosing. The stimulation indices at 5, 10 and 25 % (w/v) test item concentrations were determined to be 3.8, 6.7 and 12.7, respectively. The EC3 could not be calculated as the SI of lowest concentration tested was above 3. This study is considered to be reliable without restriction (Klimisch 1) as the study was GLP-compliant and was conducted according to OECD 429.

A test item is regarded as a sensitiser in the LLNA if the exposure to one or more test concentrations resulted in 3-fold or greater increase in incorporation of 3HTdR compared with concurrent controls, as indicated by the Stimulation Index, according to ECHA's Guidance on the Application of the CLP Criteria (2015, version 4.1). The EC3 was surpassed in the lowest concentration tested, therefore the test item is classified as a skin sensitiser.

Reference 2

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

2002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation:8 - 12 weeks (beginning of acclimatization)
- Housing: Makrolon Type 1 with wire mesh top, single caging
- Diet Pelleted standard diet, ad libitum
- Water: Tap water, ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 30 to 70%
- Photoperiod (hrs dark / hrs light): 12 hour photoperiod with artificial light

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

5%, 10% and 25%

No. of animals per dose:

4

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA assay
- Criteria used to consider a positive response: Stimulation Index >3

TREATMENT PREPARATION AND ADMINISTRATION:
Each test group of mice was treated by topical (epidermal) application to the dorsal surface of each ear lobe (left and right) with different test item concentrations of 5, 10 and 25% (w/v) in acetone:olive oil (4:1). The application volume, 25 ul, was spread over the entire dorsal surface (0 - 8 mm) of each ear lobe once daily for three consecutive days. A further group of mice was treated with an equivalent volume of the relevant vehicle alone (control animals). A hair dryer was used to dry the ear's surface as quickly as possible to avoid loss of test item applied.

Five days after the first topical application, all mice were administered with 250 uL of 78.9 uCi/mL 3HTdR (corresponding to 19.73 uCi 3HTdR per mouse) by intravenous injection via a tail vein.Approximately five hours after treatment with 3HTdR all mice were euthanised by intraperitoneal injection of Na-thiopental. The draining lymph nodes were rapidly excised and pooled for each experimental group (8 nodes per group). The level of 3HTdR incorporation was measured on a ß-scintillation counter, expressed as the number of radioactive disintegrations per minute (DPM).

Mortality, bodyweights and clinical signs of toxicity were also recorded during the study.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

A statistical analysis was conducted for assessment of the dose-response relationship and the EC3 value was calculated. EC3 is the estimated concentration of the test item required to produce a 3-fold increase in draining lymph node cell proliferative activity.

Positive control results:

The validation/positive control study was performed with alpha-Hexylcinnamaldehyde in acetone:olive oil, 4:1 (v/v) using CBA/CaOlaHsd mice in a separate study (April 2004). Stimulation indices at 5, 10 and 25 % (w/v) positive control concentrations were determined to be 2.8, 4.7 and 17.6, respectively. An EC3 of 5.5% (w/v) was calculated.

Key result

Parameter:

EC3

Value:

5.5

Parameter:

SI

Value:

2.8

Test group / Remarks:

5% test item (w/v)

Parameter:

SI

Value:

4.7

Test group / Remarks:

10% test item (w/v)

Parameter:

SI

Value:

17.6

Test group / Remarks:

25% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

574.4

Test group / Remarks:

5% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

944.4

Test group / Remarks:

10% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

3 564.2

Test group / Remarks:

25% test item (w/v)

Parameter:

other: disintegrations per minute (DPM)

Value:

202.2

Test group / Remarks:

Control

Cellular proliferation data / Observations:

No mortality was observed during the study and the test item had no significant effect on bodyweight. The ears of all animals treated with the highest concentration (25%) were slightly red after the second treatment and all four treated animals had red inflamed ears after the third treatment. Slightly red ears were observed with 10% test item in one animal after the second application and two animals after the third application. No systemic findings were, however, observed during the study period.

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

Stimulation indices at 5, 10 and 25 % (w/v) test item concentrations were determined to be 2.8, 4.7 and 17.6, respectively. An EC3 of 5.5% (w/v) was calculated.

Executive summary:

The skin sensitising potential of the test item was assessed by local lymph node assay (LLNA). Female mice were treated daily with the test item at concentrations of 5, 10 and 25% (w/v) in acetone:olive oil (4:1) by topical application to the dorsum of each ear lobe for three consecutive days. A control group of four mice was treated with the vehicle only. Five days after the first topical application the mice were injected intravenously into a tail vein with radio-labelled thymidine. Approximately five hours after intravenous injection, the mice were sacrificed, the draining auricular lymph nodes excised and pooled per group. The proliferative capacity of pooled lymph node cells was determined by the incorporation of 3H-methyl thymidine measured in a beta-scintillation counter. No mortality or adverse effects on bodyweight were observed during the study period. Redness of the ear was observed at higher concentrations and with repeat dosing. The stimulation indices at 5, 10 and 25 % (w/v) test item concentrations were determined to be 2.8, 4.7 and 17.6, respectively. An EC3 of 5.5% (w/v) was calculated. This study is considered to be reliable without restriction (Klimisch 1) as the study was GLP-compliant and was conducted according to OECD 429.

A test item is regarded as a sensitiser in the LLNA if the exposure to one or more test concentrations resulted in 3-fold or greater increase in incorporation of 3HTdR compared with concurrent controls, as indicated by the Stimulation Index, according to ECHA's Guidance on the Application of the CLP Criteria (2015, version 4.1). The EC3 was determined to be 5.5% (w/v), therefore the test item is classified as a skin sensitiser.

Reference 3

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

2002

Deviations:

yes

Remarks:

Evaluation not based on measurement of incorporated radioactivity in lymph nodes

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Species:

mouse

Strain:

NMRI

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: About 9 weeks old
- Weight at study initiation: 23 to 35g
- Housing: Transparent polycarbonate cages (macrolone type III, floor area 810 cm2) with 2 groups at 6 animals each
- Diet: Pelleted complete rodent diet "Altromin 1314", ad libitum
- Water: Domestic quality drinking water acidified with hydrochloric acid to pH 2.5 in order to prevent microbial growth, ad libitum
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21°C ± 3°C
- Humidity (%): 55% ± 15%
- Air changes (per hr): 10/hr
- Photoperiod (hrs dark / hrs light): 12 hours light and 12 hours darkness

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

5% , 10% or 25%

No. of animals per dose:

6

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Local lymph node assay
- Criteria used to consider a positive response: 0 < DI < 1 inflammation and DI > 1 allergic reaction

TREATMENT PREPARATION AND ADMINISTRATION:
Three applications of 25 uL treatment solution were made on three consecutive days, applied topically on the dorsal side of the ears. Mice were sacrificed on the fourth day and auricular lymph nodes were removed. Circular ear tissue and lymph node pairs were weighed and the lymph node cell counts were determined manually by Trypan blue exclusion using a NEUBAUER-chamber. Ear thickness was also assessed at the start and end of the study.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Positive control results:

A Differentiation Index of 2.28 was determined for undluted alpha-hexylcinnamaldehyde in a separate study (2-5 September 2003).

Key result

Parameter:

other: differentiation index

Value:

4.04

Test group / Remarks:

5% test item

Remarks on result:

other: Differentiation Index = % maximum LN cell count index and % maximum ear swelling Since a positive ear swelling was not recorded, a fixed value of 0.01 mm ear swelling was used.

Key result

Parameter:

other: differentiation index

Value:

4.77

Test group / Remarks:

10% test item

Remarks on result:

other: Differentiation Index = % maximum LN cell count index and % maximum ear swelling Since a positive ear swelling was not recorded, a fixed value of 0.01 mm ear swelling was used.

Key result

Parameter:

other: differentiation index

Value:

4.77

Test group / Remarks:

25% test item

Remarks on result:

other: Differentiation Index = % maximum LN cell count index and % maximum ear swelling Since a positive ear swelling was not recorded, a fixed value of 0.01 mm ear swelling was used.

Cellular proliferation data / Observations:

No significant effects were observed for ear thickness, ear tissue weight and lymph node weight, however a significant increase of lymph node cells was recorded. The lymph nodes of one animal in the 5% group and 10% group could not be completely removed and data of these animals were excluded from the study evaluation.

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

The Differentiation Index was determined to be 4.04, 4.77 and 4.77 at test item concentrations of 5, 10 and 25%, respectively.

Executive summary:

Female albino mice of the strain Crl:NMRI were treated with 5, 10 and 25% SYM04/130329 and a negative control (acetone/olive oil (4:1 v/v)) on three consecutive days. An amount of 25 µL of the test substance was applied on the dorsal sides of each ear. The determination of ear thickness, ear weight, lymph node weight and lymph node cell count compared with the negative control was used to determine whether the test item has a specific (sensitising) or nonspecific (irritant) stimulation potential. No significant effects were observed for ear thickness, ear tissue weight and lymph node weight, however a significant increase of lymph node cells was recorded. The Differentiation Indices were determined to be 4.04, 4.77 and 4.77 at test item concentrations of 5, 10 and 25%, respectively. This study is reliable without restriction (Klimisch 1) as it was conducted according to OECD 429 and GLP.

As the threshold value of DI=1 was exceded, the test item is considered to be a skin sensitiser at all the 3 dose levels tested.

Reference 4

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Study conducted in accordance with OECD 406 guideline and GLP. The Guinea-pig maximisation test is not the preferred study for this endpoint due to a perceived lack of sensitivity in comparison with the preferred OECD 429 test

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Species:

guinea pig

Strain:

Pirbright-Hartley

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 335 to 430 g (male) and 341 to 428 g (female)
- Housing: Collective housing up to a maximum of 5 animals per cage (Makrolon® type IV)
- Diet (e.g. ad libitum): Pellets with added vitamins, ad libitum
- Water (e.g. ad libitum): Drinking water fit for human consumption, ad libitum
- Acclimation period: 16 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 C
- Relative humidity: 30 to 70 %
- Photoperiod (hrs dark / hrs light): 12 hour photoperiod with artificial lighting (120 lux)

Route:

intradermal

Vehicle:

peanut oil

Concentration / amount:

5%

Day(s)/duration:

Day 1

Adequacy of induction:

other: No skin reactions observed after injection of the test article at 5% test item concentration.

Route:

epicutaneous, occlusive

Vehicle:

peanut oil

Concentration / amount:

100%

Day(s)/duration:

Day 7 / 48 hours

Adequacy of induction:

highest technically applicable concentration used

Route:

epicutaneous, occlusive

Vehicle:

peanut oil

Concentration / amount:

25%

Day(s)/duration:

14 days after topical induction / 24 hours

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

10 animals for control and 20 animals for treatment group

Details on study design:

RANGE FINDING TESTS:
A 5% solution of the test item with aqua ad iniect and Freund's complete adjuvant were intradermally injected into two animals. No skin reactions were observed 48 hours after treatment.

Solutions of 25, 50, 75 and 100% test item concentration were applied topically on two animals per dose and covered with an occlusive bandage and tape. Erythema was observed in one animal at 50% test item concentration and in both animals at 75 and 100% tem item concentration after 48 hours. Oedema was observed in one animal at 100% test item concentration only.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: Two intradermal injections followed by topical application under an occlusive dressing 7 days later
- Exposure period: Topical application 48 hr
- Test groups: 20 animals
- Control group: 10 animals
- Site: Shoulders, clipped area of 4 x 5 cm for topical exposure
- Frequency of applications: Once
- Duration: 9 days
- Concentrations: intradermal injection 5% ; topical application - 100%

B. CHALLENGE EXPOSURE
- No. of exposures: One
- Day(s) of challenge: 14 days after topical induction
- Exposure period: 24hr under an occlusive dressing
- Test groups: 20 animals
- Control group: 10 animals
- Site: flank, clipped area of 5 x 5 cm
- Concentrations: 25%
- Evaluation (hr after challenge): 24 and 48 hours

OTHER: Skin area evaluated on a numerical scale according to Draize
Erythema and eschar formation (0 to 4 scale)
Oedema formation (0 to 4 scale)

Positive control substance(s):

yes

Remarks:

2,4 dinitrochlorobezene was tested in a separate study (16 Dec 1994 to 9 Jan 1995).

Positive control results:

The sensitisation rate at 24 and 48 hours was 60 and 20%, respectively, for the positive control at 0.1% concentration and 10 and 0%, respectively, at 0.01% concentration. Based on the maximization scheme of Magnusson and Kligman (J. Invest. Dermatol., 52, 268-276, 1969), 2,4-dinitrochlorobenzene is classified as a moderate sensitiser at 0.1% concentration and a mild sensitiser at 0.01% concentration.

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

25%

No. with + reactions:

0

Total no. in group:

20

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

25%

No. with + reactions:

0

Total no. in group:

20

Interpretation of results:

GHS criteria not met

Conclusions:

No sensitisation was observed in guinea pigs at 24 and 48 hours after induction and challenge at 25% test item concentration.

Executive summary:

The skin sensitising potential of the test item was assessed in a guinea pig maximization test. The induction phase consisted of an intradermal injection of 5% test item in peanut oil, followed by topical application seven days later of 100% test item, secured under an occlusive dressing for 24 hours. The animals were subjected to a challenge exposure of 25% test item two weeks later and the treated skin area was evaluated 24 and 48h after application of the challenge dose. No sensitisation was observed in guinea pigs at 24 and 48 hours after induction and challenge. This study is reliable without restriction (Klimisch 1) as it was conducted according to OECD 406 and GLP.

The test item at 25 % preparation, is considered to be a non-sensitiser, according to CLP Regulation No 1272/2008.

Reference 5

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Study is siimilar to OECD 406, but not GLP and not sufficient for complete assessment of the endpoint as only a 10% preparation was tested.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Method similar to OECD 406.

GLP compliance:

not specified

Type of study:

guinea pig maximisation test

Species:

guinea pig

Strain:

Pirbright-Hartley

Sex:

not specified

Details on test animals and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 255 g
- Housing: Makrolon III cage (14 x 25 x 42 cm), 2 guinea pigs per cage
- Diet (e.g. ad libitum): Pellets
- Water (e.g. ad libitum): Tap water fit for human consumption, ad libitum
- Acclimation period: approximately 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 +/- 2 C
- Humidity (%):45 to 55 %
- Photoperiod (hrs dark / hrs light): 12 hour photoperiod with tungsten lighting (120 lux, 4000 K)

IN-LIFE DATES: From: 20/12/1983 To: 7/1/1983

Route:

intradermal

Vehicle:

peanut oil

Concentration / amount:

5% test item

Day(s)/duration:

Day 0

Adequacy of induction:

not specified

Route:

epicutaneous, open

Vehicle:

unchanged (no vehicle)

Concentration / amount:

10% test item

Day(s)/duration:

Day 1

Adequacy of induction:

non-irritant substance, but skin pre-treated with 10% SDS

Route:

intradermal

Vehicle:

peanut oil

Concentration / amount:

5% test item

Day(s)/duration:

Day 2

Adequacy of induction:

not specified

No.:

#1

Route:

epicutaneous, semiocclusive

Vehicle:

peanut oil

Concentration / amount:

2.5 % test item

Day(s)/duration:

14 days after the last induction treatment / 24 hours

Adequacy of challenge:

not specified

No.:

#2

Route:

epicutaneous, semiocclusive

Vehicle:

peanut oil

Concentration / amount:

5% test item

Day(s)/duration:

14 days after the last induction treatment / 24 hours

Adequacy of challenge:

not specified

No.:

#3

Route:

epicutaneous, semiocclusive

Vehicle:

peanut oil

Concentration / amount:

10% test item

Day(s)/duration:

14 days after the last induction treatment / 24 hours

Adequacy of challenge:

not specified

No. of animals per dose:

20 animals per treatment

Details on study design:

MAIN STUDY
A. INDUCTION EXPOSURE

Three pairs of injection, six injections in total, were made intradermally in the shaved skin: a) 0.05 mL Freund's adjuvant (1: 1 diluted in distilled water), and, b) 0.05 mL farnesol 10 % in white petrolatum (diluted 1: 1 with peanut oil). The day after the first two intradermal injections, the left half of the cropped shoulder region was treated with 10% sodium lauryl sulphate in white petrolatum to cause mild irritation and 6 - 8 hours later the test substance allergen or control substances were applied dermally. The test substance was applied in a 10% emulsion in white petrolatum and the treated area was covered with gauze and Elastoplast .The following day ( = 48 hours after the two intradermal treatments), the dresssing was removed and was followed by the 3rd intradermal injection.

- No. of exposures: 3 intradermal injections and 2 topical applications
- Exposure period: 14 days
- Test groups: 1
- Control group: Negative and positive controls
- Site: Shoulder area in a size of about 8 x 5 cm was shaved
- Frequency of applications: Daily
- Duration: 48 hours
- Concentrations: 5% farnesol for intradermal application and 10% farnesol for topical application

B. CHALLENGE EXPOSURE

The challenge exposure was carried out as a " closed patch" test 14 days after the last treatment using three different concentrations per animal. The left flank of the animals was shaved the day before the challenge and 0.5 mL of the challenge concentrations were applied in small round patches. The application area was covered with a gauze pad and the trunk was wrapped in a strip of Elastoplast. After 24 hours, the dressing was removed and the test sites were examined (24 hours post application) and then re-examined a day later (48 hours post application).

- No. of exposures: 1
- Day(s) of challenge: 1
- Exposure period: 1 day
- Test groups: 20
- Control group: 20 negative and 20 positve
- Site: flanks
- Concentrations: 100% 50% and 25% of a 10% farnesol in white Vaseline
- Evaluation (hr after challenge): 24 and 48 hours

Positive control substance(s):

yes

Remarks:

Methyl methacrylate (Merck Schuchard, Hohenbrunn)

Positive control results:

Sensitisation responses were observed in all positive control test animals.

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

2.5% test item

No. with + reactions:

0

Total no. in group:

20

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

5% test item

No. with + reactions:

0

Total no. in group:

20

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

10% test item

No. with + reactions:

0

Total no. in group:

20

Interpretation of results:

GHS criteria not met

Conclusions:

No primary irritant response was observed in guinea pigs exposed to the test item at 2.5, 5 and 10% concentration after induction and challenge.

Executive summary:

A guinea pig maximisation test was conducted according to Magnusson and Kligmann. 2,6,10-Dodecatrien-1-ol, 3,7,11-trimethyl- 10% in white Vaseline was applied in a series of intradermal and topical doses, followed by a challenge test 14 days later. Two pairs of intradermal injections of a 1:1 solution of the test item in peanut oil, with and without adjuvant, were made in the shoulder of guinea pigs. A day later, sodium lauryl sulfate in a white Vaseline vehicle was topically applied to the injection sites to induce a slight irritation and a topical application of 2,6,10-Dodecatrien-1-ol, 3,7,11-trimethyl- 10% in white Vaseline, positive control or negative control was applied six to eight hours later. The topical application was secured with dressing and removed the next day, at which point a third pair of injections were made. Fourteen days after the last injection, the challenge exposure was carried out as a closed patch test with 2.5, 5.0 and 10% 2,6,10-Dodecatrien-1-ol, 3,7,11-trimethyl- in white Vaseline. The exposure area was occluded for 24 hours after application and skin irritation and sensitisation were assessed at 24 and 48 hours after the challenge application. No primary irritant response was observed in guinea pigs exposed to 2,6,10-Dodecatrien-1-ol, 3,7,11-trimethyl- 10% in white Vaseline after induction and challenge. This study is reliable with restrictions (Klimisch 2) as the study was not GLP-compliant and no guideline was reported (although it was conducted similar to OECD 406), and the highest concentration tested was 10% test item.

According to CLP Regulation (EC) No. 1272/2008, the test item up to 10% concentration is considered to be a non-sensitiser.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (sensitising)

Additional information:

Three LLNA assays have been performed with the test substance (2004a, 2004b, 2004c). A positive response was identified in both the key study (EC3 of 5.5%) and a supporting study (EC could not be calculated as SI was greater than 3 at the lowest tested dose of 5%). In the third LLNA study, the Differentiation Index, to distinguish irritant and sensitisation responses, also produced positive responses at the 3 doses tested (5, 10 and 25%). However, a good quality regulatory guinea-pig maximisation test gave a non-sensitising result with the maximum non-irritating dose concentration of 25% (1995), and this result was supported by a similar non-GLP study in which the highest concentration tested was only 10%, but which also gave a negative response (1983). A human repeat insult patch test conducted with 107 male and female volunteers also revealed a non-sensitising outcome at a dose concentration of 15% (2013). All data considered are reliable and relevant (Klimisch 1 and 2).

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

According to CLP Regulation (EC) No 1272/2008, the test item is classified as skin sensitiser Category 1B.