Dibromomethane

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and appropriate OECD testing guidelines

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

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:

Dibromomethane

EC Number:

200-824-2

EC Name:

Dibromomethane

Cas Number:

74-95-3

Molecular formula:

CH2Br2

IUPAC Name:

dibromomethane

Test material form:

other: liquid

Details on test material:

Certificate of analysis of the test item is attched

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

At the start of the study the animals were in the weight range of 15 to 23 g, and were eight to twelve weeks old.
The temperature and relative humidity were controlled to remain within target ranges of 19 to 25°C and 30 to 70%, respectively.

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

50 µL (25 µL per ear) of the undiluted test material

No. of animals per dose:

Three groups, each of five animals

Details on study design:

Following a preliminary screening test in which 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 of the Local Lymph Node Assay.
Three groups, each of five animals, were treated with 50 µL (25 µL per ear) of the undiluted test material,
or the test material as a solution in acetone/olive oil 4: 1 at concentrations of 50% or 25% v/v.
A further group of five animals was treated with acetone/olive oil 4: 1 alone.

Positive control substance(s):

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

Results and discussion

Positive control results:

Positive Control Material
Concentration Stimulation Index Result
15% v/v in acetone/olive oile 4:1.....................................4.10..........................................Positive

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

The Stimulation Indices expressed as the mean radioactive incorporation for each treatment group devided by the mean radioactive incorporation of the vehicle control group are presented: Concentration Stimulation Indiex Result Test Material 25% v/v in acetone/olive oile 4:1.....................................0.70..........................................Negative 25% v/v in acetone/olive oile 4:1.....................................0.70..........................................Negative 50% v/v in acetone/olive oile 4:1.....................................0.63..........................................Negative 100% v/v in acetone/olive oile 4:1...................................1.39..........................................Negative Positive Control Material 15% v/v in acetone/olive oile 4:1.....................................4.10..........................................Positive

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: A table of 'Individual disintegration per minute' is attached in the : "Attached background material" section.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

Dibromomehtane is a non sensitiser.

Executive summary:

Following a preliminary screening test in which no clinical signs of toxicity were noted at a concentration of 100%, this concentration was selected as the highest dose investigated in order to assess the skin sensitisation potential of the test material in the CBA/Ca strain mouse. Three groups, each of five animals, were treated by topical application to the dorsal surface of the ear with 25 µl undiluted test material (99.5% purity, DBM) or the test material as a solution in acetone/olive oil 4:1 at concentrations of 50% or 25% v/v. A further group of five animals was treated with acetone/olive oil 4:1 alone.

The study results demonstrate that the Stimulation Index (SI) expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group were 1.39, 0.63 and 0.70 for all concentrations of the test material investigated (100%, 50% & 25%, respectively). The positive control group (a concentration of 15% of α-hexylcinnamaldehyde in 4:1 Acetone/Olive oil) showed an acceptable response for a valid study with an SI of 4.10. Hence, it was concluded that the DBM is not skin sensitizer.