Ethyl difluoroacetate

Skin sensitisation

Administrative data

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:

other: GLP, Guideline study (OECD)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (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:

Ethyl difluoroacetate

EC Number:

207-223-4

EC Name:

Ethyl difluoroacetate

Cas Number:

454-31-9

Molecular formula:

C4H6F2O2

IUPAC Name:

ethyl difluoroacetate

Details on test material:

- Name of test material (as cited in study report): Ethyl difluoroacetate
- Analytical purity: 99.9%
- Lot/batch No.: 33244/106 A
- Stability under test conditions: The stability under storage conditions over the study period was guaranteed by the sponsor, and the sponsor holds
- Other: The test substance was homogeneous by visual inspection.

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories
- Age at study initiation: 6-12 weeks
- Weight at study initiation: 19.4 g – 22.6 g
- Housing: single housed
- Diet: Kliba-Labordiät (Maus / Ratte Haltung “GLP”)
- Water (e.g. ad libitum): Tap water ad libitum
- Acclimation period: 7 days before the first test-substance application

ENVIRONMENTAL CONDITIONS
- Temperature (°C): The animals were housed in fully air-conditioned rooms. Central air-conditioning guaranteed a range of 20 – 24°C.
- Humidity (%): 30 – 70% for relative humidity
- Photoperiod (hrs dark / hrs light): 12 h / 12 h (6.00 a.m. – 6.00 p.m. / 6.00 p.m. – 6.00 a.m.)

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

Control group 1: Vehicle: propylene glycol
Test group 2: Test substance 10% in propylene glycol
Test group 3: Test substance 30% in propylene glycol
Test group 4: Test substance undiluted

No. of animals per dose:

5 animals

Details on study design:

TREATMENT PREPARATION AND ADMINISTRATION:
- 3 consecutive applications (day 0 – day 2) to the same application site
- On study day five (about 66 to 72 hours after the last application of test substance to the ears) the mice were injected intravenously with 20 μCi of 3H-thymidine in 250 μl of sterile saline into a tail vein.
- The animals were sacrificed on study day 5 about 5 hours after 3H-thymidine injection by cervical dislocation.

Statistics:

The stimulation indices of cell count, 3H-thymidine incorporation, lymph node weight and ear weight were calculated as the ratio of the test group values for these parameters divided by those of the vehicle control group.

Results and discussion

In vivo (LLNA)

Results

Parameter:

SI

Remarks on result:

other: 1.5

Any other information on results incl. tables

The stimulation indices (fold of change as compared to the vehicle control) for cell count, 3H-thymidine incorporation, lymph node weight and ear weight are summarized for each test group in the table below:

Test group	Treatment	Cell Count Stimulation Index	³H-thymidine incorporation Stimulation Index	Lymph Node weight Stimulation Index	Ear weight Stimulation Index
1	vehicle propylene glycol	1.00	1.01	1.02	1.03
2	10% in propylene glycol	0.84	1.20	0.94	1.06
3	30% in propylene glycol	1.17	1.67	1.13	1.02
4	undiluted	0.88	0.94	0.85	1.04

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

It is concluded that Ethyl difluoroacetate does not show a skin sensitizing effect in the Murine Local Lymph Node Assay under the test conditions chosen.