2-methoxy-2-methylheptane

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 Jan 2017 - 21 Feb 2017

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:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2-methoxy-2-methylheptane

EC Number:

816-311-7

Cas Number:

76589-16-7

Molecular formula:

C9H20O

IUPAC Name:

2-methoxy-2-methylheptane

Test material form:

liquid

Specific details on test material used for the study:

Identification DAIKON ETHER
Appearance Colourless liquid
Chemical name (IUPAC), synonym or trade name 2-Methoxy-2-methylheptane
CAS Number 76589-16-7

In vivo test system

Test animals

Species:

mouse

Strain:

CBA:J

Sex:

female

Details on test animals and environmental conditions:

Species: Mouse
Strain: CBA/J
Condition: Inbred, SPF-Quality
Number of Animals: 25 Females (nulliparous and non-pregnant). Five females per group.
Age at the Initiation of Dosing: Young adult animals (approximately 10 weeks old) were selected.
Weight at the Initiation of Dosing: 18.8 to 23.1 g.
Housing: polycarbonate cages containing sterilized sawdust as bedding material
Mean temperature: 22°C
Mean relative humidity: 42 to 47%
Photoperiod: 12-hour light/12-hour dark cycle
Air change: Ten or greater air changes per hour with 100% fresh air (no air recirculation)
Food: Pelleted rodent diet, ad libitum
Water: Municipal tap-water was freely available
Animal Enrichment: animals were provided with paper

Study design: in vivo (LLNA)

Vehicle:

other: Ethanol/diethylphthalate (1:3 v/v)

Concentration:

0, 25, 50, 100 % w/w

No. of animals per dose:

5

Details on study design:

Pre-screen Test: Two test item concentrations were tested; a 50% and 100% concentration. The highest concentration was the maximum concentration as required in the test guidelines.
Main Study: Three groups of five animals were treated with one test item concentration per group. The highest test item concentration was selected from the pre-screen test. One group of five animals was treated with the vehicle and another group of five animals was treated with the positive control item.
Induction - Days 1, 2 and 3
Excision of the Nodes - Day 6
Tissue Processing for Radioactivity - Day 6
Radioactivity Measurements - Day 7

Positive control substance(s):

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

Results and discussion

Positive control results:

The SI value calculated for the positive control group was 3.3.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

1.5

Test group / Remarks:

concentration: 25% of test item

Results 2

Key result

Parameter:

SI

Value:

2

Test group / Remarks:

concentration: 50% of test item

Results 3

Key result

Parameter:

SI

Value:

4.3

Test group / Remarks:

concentration: 100% of test item

Any other information on results incl. tables

Skin Reactions / Irritation

No irritation was observed in any of the test item treated or vehicle control animals, very slight erythema was noted for all positive control item treated animals between Days 1 and 3., which was considered not to have a toxicologically significant effect on the activity of the nodes.

White test item remnants were present on the dorsal surface of the ears of all animals at 100% (between Days 1 and 6), which did not hamper scoring of the skin reactions.

Systemic Toxicity

No mortality occurred and no clinical signs of systemic toxicity were observed in the animals of the main study. Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

8.2.3. Macroscopic Examination of the Lymph Nodes and Surrounding Area

The majority of auricular lymph nodes were considered normal in size, except for one node in one animal treated with the positive control, which was considered enlarged. No macroscopic abnormalities of the surrounding area were noted for any of the animals.

Radioactivity Measurements and SI Values

Mean DPM/animal values for the experimental groups treated with test item concentrations 25, 50 and 100% were 1132, 1518 and 3322 DPM, respectively. The mean DPM/animal value for the vehicle control group was 769 DPM and a mean DPM/animal value of 2522 DPM was obtained from the positive control group. The SI values calculated for the test item concentrations 25, 50 and 100% were 1.5, 2.0 and 4.3, respectively. The SI value calculated for the positive control group was 3.3.

See attachment

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

Based on these results:
• according to the recommendations made in the test guidelines (including all amendments), the test substance would be regarded as skin sensitizer.
• according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2015) (including all amendments), the test item should be classified as skin sensitizer (Category 1B).
• according to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of items and mixtures (including all amendments), the test item should be classified as skin sensitizer (Category 1B) and labeled as H317: May cause an allergic skin reaction.