2,2'-dibromobiphenyl

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Nov 09, 2016 - Jan 13, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

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)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2,2'-dibromo-1,1'-biphenyl

EC Number:

625-732-3

Cas Number:

13029-09-9

Molecular formula:

C₁₂H₈Br₂

IUPAC Name:

2,2'-dibromo-1,1'-biphenyl

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Envigo RMS B.V., Inc Postbus 6174 5960 AD Horst / The Netherlands
- Age at study initiation: Pre-test and Main test: 8 - 9 weeks
- Weight at study initiation: Pre-test and Main test: 19.9+/- 0.9 g
- Housing: grouped per dose
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 + 2°C
- Humidity (%): 45-65%
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: day 1 To: day 6

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

5, 10, and 25 (w/w)

No. of animals per dose:

5

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: 50% in MEK
- Irritation: No
- Lymph node proliferation response: -

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: OECD 429
- Criteria used to consider a positive response: Stimulation index > 3

Positive control substance(s):

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

Statistics:

Standard statistical methods have been applied for data processing.

Results and discussion

Positive control results:

Conc. SI
0%: 1.00
5% 1.50
10% 3.84
25% 11.76

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

2.4

Test group / Remarks:

Test Group: 10% in MEK

Results 2

Key result

Parameter:

SI

Value:

4

Test group / Remarks:

Test Group: 36% in MEK

Results 3

Key result

Parameter:

SI

Value:

3.1

Test group / Remarks:

Test Group: 50% in MEK

Cellular proliferation data / Observations:

CELLULAR PROLIFERATION DATA : see "any other information on results"

EC3 CALCULATION : EC3 = (a-c) [(3-d)/(b-d)] + c; a,b,c,d = co-ordinates of the two pairs of data lying immediately above and below the S.I. value of 3 on the LLNA dose response plot

CLINICAL OBSERVATIONS: No deaths occurred during the study period. No symptoms of local skin irritation at the ears of the animals and no signs of systemic toxicity were observed during the study period.

BODY WEIGHTS: The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age.

Any other information on results incl. tables

Calculation of Stimulation Indices per Dose Group

Test item concentration	Group Calculation
	Mean DPM per animal (2 lymph nodes)	SD	S.I.
MEK (Vehicle Control)	1489.8	800.1	1.0
10 % Test Item in MEK	3587.2	1497.3	2.4
25 % Test Item in MEK	6033.2	2096.6	4.0
50 % Test Item in MEK	4562.8	1162.6	3.1

Applicant's summary and conclusion

Interpretation of results:

Category 1B (indication of skin sensitising potential) based on GHS criteria

Conclusions:

The test item was found to be a skin sensitiser and an EC3 value of 15.6% was derived.

Executive summary:

The informtion for this endpoint study record was obtained from an experimental study. The OECD GLP criteria were met and the methods applied are fully compliant with OECD TG 429.

For this purpose a local lymph node assay was performed using test item concentrations of 10, 25, and 50% (w/w). The highest concentration tested was the highest concentration that could technically be achieved.

The test item was found to be a skin sensitiser in this assay and an EC3 value of 15.6% was derived.