4,4'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one]

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From19 Oct 2005 to 8 Nov 2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD 429), GLP compliant

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

4,4'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one]

EC Number:

222-530-3

EC Name:

4,4'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one]

Cas Number:

3520-72-7

Molecular formula:

C32H24Cl2N8O2

IUPAC Name:

4,4'-[(3,3'-dichlorobiphenyl-4,4'-diyl)didiazene-2,1-diyl]bis(5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one)

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
- Source: Harlan Netherlands, Horst, The Netherlands
- Age at study initiation: 6-8 weeks
- Weight prior to treatment: 20.1 +/- 1.2 g (mean +/- SD)
- Housing: individually in Macrolon cages
- Diet (ad libitum): pelleted standard diet (Harlan Winkelmann, Borchen, Germany)
- Water (ad libitum): tap water
- Acclimation period: yes, but duration not stated

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3
- Humidity (%): 30-70
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

methyl ethyl ketone

Concentration:

0, 2.5, 5 and 10% in vehicle

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
To determine the most suitable vehicle a pre-test was performed using the vehicles listed in OECD Guidline 429. Based on the results of this pre-test methyl ethyl ketone was selected as vehicle. To determine the highest non-irritant and technically applicable test item concentration, a pretest was performed in two mice with concentrations of 1.25, 2.5, 5 and 10% in methyl ethyl ketone. The top dose is the highest technically achievable concentration. Due to the intense orange colour of the test item local irritation reactions such as ear redness could not be examined.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response:
A test item is regarded as a sensitiser in the LLNA if the following criteria are fulfilled:
- First, that exposure to at least one concentration of the test item resulted in an
incorporation of 3HTdR at least 3-fold or greater than that recorded in control mice, as
indicated by the stimulation index.
- Second, that the data are compatible with a conventional dose response, although
allowance must be made (especially at high topical concentrations) for either local
toxicity or immunological suppression.

TREATMENT PREPARATION AND ADMINISTRATION:
Application volume 25 µl, applied on the dorsal surface of each ear lobe, spread over the entire dorals surface, once daily for three consecutive days

Positive control substance(s):

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

Results and discussion

Positive control results:

EC3: 22.2%

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

1.12

Test group / Remarks:

2.5%

Remarks on result:

other: no indication of skin sensitisation based on in vivo test

Results 2

Parameter:

SI

Value:

1.14

Test group / Remarks:

5%

Remarks on result:

other: no indication of skin sensitisation based on in vivo test

Results 3

Parameter:

SI

Value:

1.33

Test group / Remarks:

10%

Remarks on result:

other: no indication of skin sensitisation based on in vivo test

Results 4

Parameter:

other: disintegrations per minute (DPM)

Value:

2 750.32

Test group / Remarks:

2.5%

Remarks on result:

other: no indication of skin sensitisation based on in vivo test

Results 5

Parameter:

other: disintegrations per minute (DPM)

Value:

2 795.81

Test group / Remarks:

5%

Remarks on result:

other: no indication of skin sensitisation based on in vivo test

Results 6

Parameter:

other: disintegrations per minute (DPM)

Value:

3 267.7

Test group / Remarks:

10%

Remarks on result:

other: no indication of skin sensitisation based on in vivo test

Any other information on results incl. tables

Due to the intense orange colour of the test item local irritation reactions such as ear redness could not be examined.

The EC3 value could not be calculated, since all SI were < 3.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of this study the test item was not senitising in the LLNA test

Executive summary:

In the study the test item suspended in methyl ethyl ketone was assessed for its possible contact allergenic potential. For this purpose a local lymph node assay was performed according to guideline OECD 429, using test item concentrations of 2.5, 5 and 10%. No systemic findings were observed during the study period. Due to the intense orange colour of the test item local irritation reactions such as ear redness could not be examined. In this study Stimulation Indices (S.I.) of 1.12, 1.14 and 1.33 were determined with the test item at concentrations of 2.5, 5 and 10% (w/v) in methyl ethyl ketone, respectively. The test item was not a skin sensitiser in this assay.