1,1'-ethan-1,2-diylbisbenzene, brominated

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 2nd, 2009 - March 24th, 2009

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (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

Reference

Name:

Unnamed

Type:

Constituent

Details on test material:

- Name of test material (as cited in study report): SH-1
- Chemical name of test material (as cited in study report): Benzene, 1,1'-(1,2-ethanediyl)bis-, brominated
- Composition of test material, percentage of components:
-- 0-2 % Penta bromodiphenylethane (CAS No.: 137563-31-6)
-- 40-80 % Hexa bromodiphenylethane (CAS No.: 137563-32-7)
-- 1-20 % Hepta bromodiphenylethane (CAS No.: 137563-33-8)
-- 1-30 % Octa bromodiphenylethane (CAS No.: 137563-34-9)
-- 0-10 % Nona bromodiphenylethane (CAS No.: 137563-35-0)
-- 0-5 % Deca bromodiphenylethane (CAS No.: 137563-36-1, 84852-53-9)
- Physical state: white powder
- Analytical purity: > 99%
- Batch No.: 20090105
- Expiration date of the lot/batch: January 08th, 2011
- Storage condition of test material: room temperature in the dark

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Limited, Bicester, Oxon, UK
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 15 to 23 g
- Housing: individually housed in suspended solid-floor polypropylene cages furnished with softwood woodflakes
- Diet (e.g. ad libitum): 2014 Teklad Global Rodent diet supplied by Harlan Teklad, Blackthorn, Bicester, Oxon, UK
- Water (e.g. ad libitum):mains tap water
- Acclimation period: at least 5 days

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

IN-LIFE DATES: From: March 2nd, 2009 - March 24th, 2009

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Remarks:

This vehicle was chosen as it produced the highest concentration that was suitable for dosing.

Concentration:

Groups of four mice were treated with the test material at concentrations of 25%, 10% or 5% w/w in propylene glycol.

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
see section "any other informations on material and methods" below.

MAIN STUDY
- Criteria used to consider a positive response: Stimulation Index of 3.0 or greater was considered as a positive result.
- 3HTdR incorporation was measured by ß-scintillation counting.
- The number of radioactive disintegrations per minute was then measured using the Beckman LS6500 scintillation system (Beckman Instruments Inc, Fullerton, CA, USA).

INTERPRETATION OF RESULTS:
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 ratio of 3HTdR incorporation into lymph node cells of test nodes relative to that recorded for the control nodes (Stimulation Index).

Positive control substance(s):

other: Phenylacetaldehyde (90%)

Results and discussion

Positive control results:

Methods:
One group of five animals was treated with 50 μl (25 μl per ear) of Phenylacetaldehyde (90%) as a solution in propylene glycol at a concentration of
2.5% v/v. A further control group of five animals was treated with propylene glycol alone.
RESULTS:
Positive, as the stimulation index was found to be 8.00 at 2.5 % v/v of the positive test substance in propylene glycol.
Phenylacetaldehyde (90%) was considered to be a sensitiser under the conditions of the test.

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: At all tested concentrations the stimulation index was < 3.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see table below

Any other information on results incl. tables

A stimulation index of less than 3 was recorded for the three concentrations of the test material (25%, 10% and 5% w/w in propylene glycol).

Table 1: Disintegrations per Minute, Disintegrations per Minute/Node and Stimulation Index

Concentration (% v/V) in acteone/olive oil 4:1	dpm	dpm/Node^a	Stimulation Index^b	Result
Vehicle	3363.26	420.41	na	na
5	3976.04	497.01	1.18	Negative
10	3916.15	489.52	1.16	Negative
25	4892.47	611.56	1.45	Negative

a= Disintegrations per minute/node obtained by dividing the disintegration per minute value by 8 (total number of lymph nodes)

b= Stimulation Index of 3.0 or greater indicates a positive result

na = not applicable

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

According to EU and GHS classification criteria for skin sensitisation no classification is required.

Executive summary:

A study was performed to assess the skin sensitisation potential of the test substance in the CBA/Ca strain mouse following topical application to the dorsal surface of the ear according to OECD Guideline 429 ("Skin Sensitisation: Local Lymph Node Assay"). Following a preliminary screening test in which no clinical signs of toxicity were noted at a concentration of 25% w/w, this concentration was selected as the highest dose investigated in the main test of the Local Lymph Node Assay. Three groups, each of four animals, were treated with 50 μl (25 μl per ear) of the test material as a suspension in propylene glycol at concentrations of 25%, 10% or 5% w/w. A further group of four animals was treated with propylene glycol alone.

The Stimulation Index expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group were less than 3 at all tested concentrations. Therefore the test substance SH-1 was considered to be non-sensitising to the skin.