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Toxicological information

Skin sensitisation

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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

Constituent 1
Chemical structure
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)

Resultsopen allclose all
Parameter:
SI
Value:
1
Test group / Remarks:
1% induction
Parameter:
SI
Value:
1.1
Test group / Remarks:
3% induction
Key result
Parameter:
SI
Value:
1.54
Test group / Remarks:
10% induction
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