2-(1-methylethoxy)ethyl acetate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 - 18 Sep 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(adopted 22 July 2010)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2-(1-methylethoxy)ethyl acetate

EC Number:

242-901-3

EC Name:

2-(1-methylethoxy)ethyl acetate

Cas Number:

19234-20-9

Molecular formula:

C7H14O3

IUPAC Name:

2-(propan-2-yloxy)ethyl acetate

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 57033
- Expiration date of the lot/batch: 25 November 2014

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark.

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/Ca (CBA/CaOlaHsd)

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon, UK
- Weight at study initiation: 15 - 23 g
- Housing: individually in suspended solid-floor polypropylene cages furnished with softwood wooldflakes
- Diet: 2014C Teklad Glabal Rodent diet (Harlan Laboratories UK Ltd,. Oxoon, UK); ad libitum
- Water: tap water; ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25
- Humidity (%): 30 - 70
- Air changes (per hr): approx. 15
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

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

Remarks:

(AOO)

Concentration:

100%, 50%, and 25%

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
One mouse was treated by daily application of 25 µL of the undiluted test item to the dorsal surface of each ear for three consecutive days. Local skin irritiaton and any clinical signs were recorded until day 6.
- Irritation: A mean ear thickness increase of >= 25% was considered to indicate excessive irritation. Excessie local skin irritiaotn is also indicated by and erythema score of >=2.
As no clinical signs of toxicity were noted at a concentration of 100%, this concentration was selected as the highest dose investigated in the main test.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: The test item will be regarded as a sensitiser if at least one concentration of the test item results in a threefold or greater increase in ³HTdR incorporation compared to control value. Any test item failing to produce a threefold or greater increase in ³HTdR incorporation will be classified as a "non-sensitiser".

TREATMENT PREPARATION AND ADMINISTRATION:
3 groups of 4 animals were treated with 50 µL (25 µL per ear) of the test substance at concentrations of 100%, 50% or 25%, respectively, or the vehicle (AOO) for 3 consecutive days (day 1, 2, 3). At day 6 all mice were injected via the tail vein with 250 µL of PBS containing ³H-methyl thymidine (³HTdR: 80 µCi/mL, specific activity 2.0 Ci/mmol, ARC UK Ltd) giving a total of 20 µCi to each mouse.
All animals were observed twice daily on days 1, 2 and 3 and once daily on days 4, 5 and 6. 5 hours following the administration of ³HTdR all mice were killed. The draining auricular lymph nodes from the four mice were excised and pooled for each experimental group.
The proliferation response of lymph node cells was expressed as the number of radioactive disintegrations per minute per lymph node (disintegrations per minute/node) and as the ration of ³HTdR incorportation into lymph node cells of test nodes relative to that recorded for the control nodes (Stimulation Index; SI).

Positive control substance(s):

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

Results and discussion

Positive control results:

- Stimulation index, positive control: 5.76

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: - Test item (25%): 1.49 - Test item (50%): 1.26 - Test item (100%): 1.10

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: DPM: - Negative control: 14101.54 - Test item (25%): 21038.54 - Test item (50%): 17702.86 - Test item (100%): 15522.68 DPM/Node: - Negative control: 1762.69 - Test item (25%): 2629.82 - Test item (50%): 2212.86 - Test item (100%): 1940.34

Any other information on results incl. tables

Bodyweights and body weight changes were comparable to the corresponding control group over the study period.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

CLP: not classified
DSD: not classified