2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide]

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 09 AUG 2006 to 15 AUG 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: guideline study (OECD TG 429)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

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:

GLP according to Chemikaliengesetz and Directive 88/320/EEC

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide]

EC Number:

225-822-9

EC Name:

2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[N-(2,4-dimethylphenyl)-3-oxobutyramide]

Cas Number:

5102-83-0

Molecular formula:

C36H34Cl2N6O4

IUPAC Name:

2,2'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis[N-(2,4-dimethylphenyl)-3-oxobutanamide]

Test material form:

solid: nanoform

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- strain: CBA/CaOlaHsd
- Source: Harlan Netherlands
- Age at study initiation: 7-8 weeks (beginning of acclimatization)
- Weight at study initiation: mean: 19.2 g (17.1-20.8)
- Housing: individually, Makrolon Type I cages
- Diet: pelleted standard diet (Harlan Winkelmann, Borchen), ad libitum
- Water: tap water, ad libitum
- Acclimatization: yes (acclimatization period not given)


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/-3
- Humidity (%): 30-85%
- Photoperiod (hrs dark / hrs light): 12 hrs/12 hrs

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

0%, 2.5%, 5%, 10% (w/v)

No. of animals per dose:

4 females per dose group
2 females in the pre-test

Details on study design:

RANGE FINDING TESTS:
- non GLP
- Compound solubility: 10% (w/v) suspension in propylene glycol was the highest technically applicable concentration; higher concentrations could also not be achieved with other vehicles
- Irritation: no irritation effects were observed at these concentrations after a single application
- Lymph node proliferation response: no data


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response:
1: exposure to at least one concentration of the test item resulted in an incorporation of 3H-methyl thymidine at least 3-fold or greater than that recorded in control mice as indicated by the stimulation index
2: data are compatible with a conventional dose response, although allowance must be made for either local toxicity or immunological suppression


TREATMENT PREPARATION AND ADMINISTRATION:
- individual preparation of weight volume dilutions using a magnetic stirrer as homogenizer
- test item preparations were made freshly before each dosing occasion
- 25 µl were spread over the entire dorsal surface of each ear lobe once daily for three consecutive days

Positive control substance(s):

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

Statistics:

- calculation of mean values and standard deviations for body weight

Results and discussion

Positive control results:

Stimulation indices of 2.30, 4.31 and 11.21 were determined with the positive control substance at concentrations of 5%, 10% and 25% (w/v), respectively, in acetone:olive oil (4+1). An EC3 value of 6.7% (w/v) was calculated.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

2.26

Test group / Remarks:

10%

Results 2

Key result

Parameter:

SI

Value:

17.1

Test group / Remarks:

2,5%

Remarks on result:

other: Stimulation indices were all below 3. The following SI were calculated: 2.5% test item: 1.71 5% test item: 1.32 10% test item: 2.26

Results 3

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: see Remark

Remarks:

There was a dose dependent increase in the dpm, which were measured for the pooled lymph nodes of each treatment group (8 lymph nodes per dose group): Background: 17.56 or 20.36 dpm Control group: 3102.24 dpm 2.5% test item: 5291.91 dpm 5% test item: 4100.26 dpm 10% test item: 6990.34 dpm

Results 4

Key result

Parameter:

SI

Value:

1.32

Test group / Remarks:

5%

Any other information on results incl. tables

The animals did not show any clinical signs during the course of the study and no cases of mortality were observed. The body weight of the animals was within the normal range. Calculation of the EC3 value was not performed, because no test concentration produced a SI of 3 or higher.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

The test substance was not sensitising in this LLNA in concentrations up to 10% (w/v) in propylene glycol, the highest technically achievable concentration.

Executive summary:

In the study the test item suspended in propylene glycol was assessed for its possible contact allergenic potential.

For this purpose a local lymph node assay was performed using test item concentrations of 2.5, 5 and 10% (w/v).

The animals (4 female mice/dose grouop) did not show any clinical signs during the course of the study and no cases of mortality were observed. In this study Stimulation Indices (S.I.) of 1.71, 1.32 and 2.26 were determined with the test item at concentrations of 2.5, 5 and 10% (w/v) in propylene glycol, respectively. The results obtained with the positive control confirmed the validity of the test.

The test item was not a skin sensitiser in this assay. Therefore, the test item has not to be classified as skin sensitiser according to Regulation (EC) No 1272/2008.