N,N'-diphenyl-p-phenylenediamine

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Skin sensitization potency and cross-reactivity of p-phenylenediamine and its derivatives evaluated by non-radioactive murine local lymph node assay and guinea-pig maximization test

Author:

Yamano T. and Shimizu M.

Year:

2009

Bibliographic source:

Contact Dermatitis 2009: 60: 193–198

Materials and methods

Principles of method if other than guideline:

The LLNA was performed as reported by Yamano et al., 2003
Four female Balb/c mice received a topical induction of 0, 1, 3, 10 or 30% of the test substance. The ear thickness index, cellularity index and BrdU incorporation index were determined.

GLP compliance:

not specified

Type of study:

mouse local lymph node assay (LLNA): BrdU-ELISA

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-diphenyl-p-phenylenediamine

EC Number:

200-806-4

EC Name:

N,N'-diphenyl-p-phenylenediamine

Cas Number:

74-31-7

Molecular formula:

C18H16N2

IUPAC Name:

N,N'-diphenyl-p-phenylenediamine

Test material form:

solid

Specific details on test material used for the study:

- The tested chemical was of superior grade and purchased from Tokyo Kasei Co., Ltd. (Tokyo, Japan).
- Name of substance (as cited in article): N,N'-diphenyl-p-phenylenediamine

In vivo test system

Test animals

Species:

mouse

Strain:

Balb/c

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: CLEA Japan (Tokyo, Japan)
- Age at study initiation: Six-week to eight-week-old

Study design: in vivo (LLNA)

Vehicle:

not specified

Concentration:

TEST CONCENTRATIONS
0, 1, 3, 10 and 30%

No. of animals per dose:

4

Details on study design:

MAIN STUDY
- Irritation/ ear thickness measurements: Skin irritation was judged by measuring ear thickness at the time of auricular lymph node excision.
- Cellularity index: Total lymph node cell count in a chemical treated animal divided by mean lymph node cell count in the control group
- 5-bromo-29-deoxyuridine (BrdU) incorporation index: expressed as optical density in enzyme-linked immunosorbent assay, calculated by dividing BrdU incorporation per well of cells from a chemical-treated animal by mean BrdU incorporation per well of cells from the control group
- Stimulation index (SI): calculated by multiplying the cellularity index by the BrdU incorporation index.
- Minimum induction dose: The minimum dose at which statistically significant increase in the SI was detected compared with the control.

ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: a chemical was designated positive when a statistically significant increase in the SI value was obtained using a non-irritant dose.

Statistics:

Index values for each chemical-treated group and the vehicle-treated control group were compared via Dunnett’s or Steel’s multiple comparison method using a STATLIGHT software package (Yukms Co., Ltd, Tokyo, Japan).

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

1

Test group / Remarks:

1% induction

Results 2

Parameter:

SI

Value:

1.1

Test group / Remarks:

3% induction

Results 3

Key result

Parameter:

SI

Value:

1.54

Test group / Remarks:

10% induction

Results 4

Parameter:

SI

Value:

1.68

Test group / Remarks:

30% induction

Cellular proliferation data / Observations:

The minimum induction dose was determined to be 10%.

Any other information on results incl. tables

Table. Results of LLNA

%	Ear thickness index	Cellularity index	BrdU incorporation index
0	1.00 ± 0.04	1.0 ± 0.1	1.0 ± 0.1
1	0.99 ± 0.04	1.0 ± 0.1	1.0 ± 0.2
3	1.01 ± 0.04	1.0 ± 0.1	1.1 ± 0.1
10	1.03 ± 0.05	1.1 ± 0.1	1.4 ± 0.3*
30	1.01 ± 0.05	1.2 ± 0.2*	1.4 ± 0.3

* Significantly different from control, p<0.05

Applicant's summary and conclusion

Interpretation of results:

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