Reaction mass of (R*,R*)-7-methoxy-3,7-dimethyl-2-octanol and (R*,S*)-7-methoxy-3,7-dimethyl-2-octanol

Endpoint summary

Description of key information

In a GLP study conducted in compliance with OECD Guideline 4442B with the registered substance, an EC1.6 value could not be determined because SI<1.6 up to 100%.

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08-21 November 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 442B (Skin Sensitization: Local Lymph Node Assay: BrdU-ELISA)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

27 April 2017

Type of study:

mouse local lymph node assay (LLNA): BrdU-ELISA

Species:

mouse

Strain:

other: CBA/J (CBA/JRj)

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Elevage Janvier Labs, Le Genest-Saint-Isle, France.
- Age at study initiation: 8 weeks
- Weight at study initiation: 20.2-23.8 g
- Housing: Animals were individually housed in suspended solid-floor polypropylene cages furnished with softwood wood flakes.
- Diet: Teklad Global 16% Protein Rodent Diet (Envigo, 2016), ad libitum
- Water: Drinking water (tap water from public distribution system), ad libitum
- Acclimation period: at least5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19-25 °C
- Humidity: 30-70 %
- Air changes: 10 changes/h
- Photoperiod: 12 h dark / 12 h light

Vehicle:

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

Concentration:

Preliminary test: 100 %
Main test: 25, 50 and 100 %

No. of animals per dose:

Preliminary test: one animal
Main test: 4 females/dose

Details on study design:

PRELIMINARY TEST:
- The mouse was treated by daily application of 25 μL of the test item undiluted (100 %) to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The mouse was observed daily from day 1. Any signs of toxicity or excessive local irritation noted during this period were recorded. Ear thickness was recorded on Days 1, 3 and 6.
- No cutaneous reactions were noted at the concentration of 100 %. Therefore this concentration was chosen as the highest concentration for the main study.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT:
- Animals were randomly allocated to the groups.
- Name of test method: Local Lymph Node Assay (LLNA:BrdU)
- Criteria used to consider a positive response: Test item should be classified if at least one concentration of the test item results in a SI≥ 1.6, as sensitiser. Any test item failing to produce a SI> 1.6 was classified as a "non-sensitiser". However, the strength of the dose-response relationship, the statistical significance and the consistency of the solvent/vehicle and positive control responses may also be used when determining whether a borderline result (i.e. SI value between 1.6 and 1.9) is declared positive.

TREATMENT PREPARATION AND ADMINISTRATION: 25 µL of control and test item were applied to the dorsal surface of both ears on Days 1, 2 and 3. On Day 5, 0.5 mL (5 mg/mouse) of BrdU (10 mg/mL) solution was injected by intra-peritoneal route. On day 6 (end of the test), the animals were were sacrificed by pentobarbital sodium and the auricular lymph nodes were excised. Then, the proliferation of lymphocytes in the draining auricular lymph nodes was determined by measurement of BrdU content in DNA of lymphocyte with ELISA kit.

Positive control substance(s):

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

Statistics:

No data

Positive control results:

The EC1.6 of the current positive control, tested with HCA, was 18.51%. Therefore, the positive control is classified as sensitiser, as expected.

Key result

Parameter:

other: EC1.6

Remarks:

%

Remarks on result:

not determinable

Key result

Parameter:

SI

Value:

1.04

Test group / Remarks:

25%

Key result

Parameter:

SI

Value:

1.28

Test group / Remarks:

50%

Key result

Parameter:

SI

Value:

1.3

Test group / Remarks:

100%

Clinical observations and mortality

No mortality and no signs of systemic toxicity were noted in the test and control animals during the test.

Bodyweights

Bodyweight changes of the test animals between Day 1 and Day 6 were comparable to those observed in the corresponding control group animals over the same period.

Local irritation

Dryness of the skin was noted on Day 6 in all animals treated with undiluted test item.

No significant increase in ear thickness and in ear weight was noted in animals treated at 25, 50 and 100 %. Therefore, the test item has to be considered as not excessively irritant at these concentrations.

 

Table 7.4.1/1: BrdU index & Stimulation index per group and calculation of EC_1.6

Groups	Test item	Brdu-index (Mean*)	Stimulation Index (SI)	Result
1	0 (AOO)	0.491	-	Negative
2	25 %	0.510	1.04	Negative
3	50 %	0.629	1.28	Negative
4	100 %	0.640	1.30	Negative

Interpretation of results:

GHS criteria not met

Conclusions:

The test item does not require any classification for skin sensitisation in accordance with CLP Regulation (EC) No 1272/2008 and GHS Regulation.

Executive summary:

In a local lymph node assay (LLNA:BrdU) performed according to OECD Guideline 442B and in compliance with GLP, groups of CBA/J mice (4 females/dose) were topically applied with 25 µL of the registered substance at concentrations of 25, 50 and 100 % to the dorsal surface of both ears for three consecutive days. Vehicle control group of four females received the vehicle (acetone/olive oil (4/1; v/v)). On Day 5, 0.5 mL of BrdU solution (10 mg/mL) was injected by intra-peritoneal route. On Day 6, the proliferation of lymphocytes in the draining auricular lymph nodes was determined by measurement of BrdU content in DNA of lymphocyte with ELISA kit and Stimulation Indices (SI) were calculated. Animals were observed for mortality, clinical signs and body weight during the study. The test concentrations for the main study were determined from a preliminary study (100% on one animal).

No mortality and no signs of systemic toxicity were noted in the treated and control animals during the test. Dryness of the skin was noted on Day 6 in all animals treated with undiluted test item. No significant increase in ear thickness and in ear weight was noted in animals treated at 25, 50 and 100%. Therefore, the test item has to be considered as not excessively irritant at these concentrations.

Stimulation Index was 1.04, 1.28 and 1.30 for the treated groups at 25, 50 and 100%, respectively. The EC1.6 could therefore not be determined.

The EC1.6 of the current positive control, tested with HCA, was 18.51%. Therefore, the positive control is classified as sensitiser, as expected.

Therefore, the registered substance does not require any classification for skin sensitisation in accordance with CLP Regulation (EC) No 1272/2008 and GHS Regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

In a local lymph node assay (LLNA:BrdU) performed according to OECD Guideline 442B and in compliance with GLP, groups of CBA/J mice (4 females/dose) were topically applied with 25 µL of the registered substance at concentrations of 25, 50 and 100% to the dorsal surface of both ears for three consecutive days. Vehicle control group of four females received the vehicle (acetone/olive oil (4/1; v/v)). On Day 5, 0.5 mL of BrdU solution (10 mg/mL) was injected by intra-peritoneal route. On Day 6, the proliferation of lymphocytes in the draining auricular lymph nodes was determined by measurement of BrdU content in DNA of lymphocyte with ELISA kit andStimulation Indices (SI) were calculated. Animals were observed for mortality, clinical signs and body weight during the study. The test concentrations for the main study were determined from a preliminary study (100% on one animal).

No mortality and no signs of systemic toxicity were noted in the treated and control animals during the test. Dryness of the skin was noted on Day 6 in all animals treated with undiluted test item. No significant increase in ear thickness and in ear weight was noted in animals treated at 25, 50 and 100%. Therefore, the test item has to be considered as not excessively irritant at these concentrations.

Stimulation Index was 1.04, 1.28 and 1.30 for the treated groups at 25, 50 and 100%, respectively. The EC1.6 could therefore not be determined.

The EC1.6 of the current positive control, tested with HCA, was 18.51%. Therefore, the positive control is classified as sensitiser, as expected.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

No skin sensitisation potential could be identified in a LLNA-Brdu study (conducted according to OECD Guideline 442B) with the registered substance tested up to 100%, therefore the registered substance does not require any classification for skin sensitisation in accordance with CLP Regulation (EC) No 1272/2008 and GHS Regulation.