Methyl 3-methoxypropionate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2010

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

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:

Methyl 3-methoxypropionate

EC Number:

223-358-1

EC Name:

Methyl 3-methoxypropionate

Cas Number:

3852-09-3

Molecular formula:

C5H10O3

IUPAC Name:

methyl 3-methoxypropanoate

Details on test material:

- Lot/batch No.: M50623Y02
- Storage condition of test material: at room temperature

In vivo test system

Test animals

Species:

mouse

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories S.r.l.
- Age at study initiation: 10 weeks old
- Weight at study initiation: 20.0-21.6
- Housing: group caging
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.0-25.9
- Humidity (%): 31-87
- Air changes (per hr): 15-20
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

100 (undiluted), 50, 25, 0 % w/v

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
- Irritation: no irritation observed

MAIN STUDY
- Pooled treatment group approach
- Criteria used to consider a positive response:
a) That exposure to at least one concentration of the test item resulted in an incorporation of 3HTdR at least 3-fold or greater than recorded in control mice, as indicated by the stimulation index.
b) The data are compatible with a conventional dose response, although allowance must be made (especially at high topical concentrations) for either local toxicity or immunological suppression.

TREATMENT PREPARATION AND ADMINISTRATION:
Animals were topically dosed with 25 µL of the appropriate formulation using a pipette on the dorsal surface of each ear. Each animal was dosed once a day for three consecutive days (Days 1, 2 and 3). There was no treatment on Days 4, 5 and 6.

Positive control substance(s):

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

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

0.5

Test group / Remarks:

100%

Results 2

Parameter:

SI

Value:

0.7

Test group / Remarks:

50%

Results 3

Parameter:

SI

Value:

0.9

Test group / Remarks:

25%

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the conditions of the present assay, methyl 3-methoxypropionate, tested in a suitable vehicle, was shown to have no sensitisation potential (non-sensitizer) in the Local Lymph Node Assay.

Executive summary:

The Preliminary Irritation/Toxicity Test was performed in CBA/CaOlaHsd mice using two doses (2 animals/dose): 100 % (undiluted) and 50 % (w/v) in AOO. Based on the observations recorded in the preliminary test, the 100 % (undiluted) was selected as top dose for the main test.

 

In the main assay, twenty female CBA/CaOlaHsd mice were allocated to five groups of four animals each:

-   three groups received methyl 3-methoxypropionate (formulated in AOO) at 100 % (undiluted), 50 and 25 % (w/v) concentrations,

-   the negative control group received the vehicle (AOO),

-   the positive control group received 25 % (w/v) HCA (dissolved in AOO).

 

The test item solutions were applied on the dorsal surface of ears of experimental animals (25 µL/ear) for three consecutive days (Days 1, 2 and 3). There was no treatment on Days 4, 5 and 6. The cell proliferation in the local lymph nodes was measured by incorporation of tritiated methyl thymidine (³HTdR) and the values obtained were used to calculate stimulation indices (SI).

 

No mortality or signs of systemic toxicity were observed during the study. Minimal amount of residual test item was observed on the ears of the experimental animals in the 100 % (undiluted) dose group on Days 1-3. There were no indications of any irritancy at the site of application. No treatment related effects were observed on the mean body weight changes in the study.

 

The stimulation index values were 0.5, 0.7 and 0.9 at concentrations of 100 % (undiluted), 50, and 25 % (w/v), respectively.

 

The result of the positive control substance alpha-Hexylcinnamaldehyde (HCA) dissolved in the same vehicle was used to demonstrate the appropriate performance of the assay. A lymphoproliferative response in line with historic positive control data was noted for the positive control chemical, this result confirmed the validity of the assay.

 

In conclusion, under the conditions of the present assay, methyl 3-methoxypropionate, tested in a suitable vehicle, was shown to have no sensitisation potential (non-sensitizer) in the Local Lymph Node Assay.