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Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
Data is from peer reviewed journal.

Data source

Reference
Reference Type:
publication
Title:
Sensitization to azo dyes: negative patch tests to yellow and red dyes
Author:
M.A.C Thierbach et.al
Year:
1992
Bibliographic source:
Contact Dermatitis, 1992

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: as mentioned below
Principles of method if other than guideline:
Patch tests were performed using the test chemical and other azo dyes to determine their sensitization potential on humans
GLP compliance:
not specified
Type of study:
patch test
Justification for non-LLNA method:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]
EC Number:
228-787-8
EC Name:
2,2'-[(3,3'-dichloro[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]
Cas Number:
6358-85-6
Molecular formula:
C32H26Cl2N6O4
IUPAC Name:
Pigment Yellow 12
Test material form:
solid
Details on test material:
Name of the chemical: 2-{2-[2-chloro-4-(3-chloro-4-{2-[2-oxo-1-(phenylcarbamoyl)propyl]diazen-1-yl}phenyl)phenyl]diazen-1-yl}-3-oxo-N-phenylbutanamide
Common Name: C.I. Pigment Yellow 12
Molecular Formula: C32H26Cl2N6O4
Molecular Weight: 629.5014 g/mol
SMILES Notation: CC(=O)C(/N=N/c1c(cc(cc1)c2cc(c(cc2)/N=N/
C(C(=O)Nc3ccccc3)C(=O)C)Cl)Cl)C(=O)Nc4ccccc4
InChI: 1S/C32H26Cl2N6O4/c1-19(41)29(31(43)35-23-9-5-3-6-10-23)39-37-27-15-13-21(17-25(27)33)22-14-16-28(26(34)18-22)38-40-30(20(2)42)32(44)36-24-11-7-4-8-12-24/h3-18,29-30H,1-2H3,(H,35,43)(H,36,44)/b39-37+,40-38+
Substance Type: Organic
Physical State: Solid

In vivo test system

Test animals

Species:
other: Human
Strain:
other: Not specified
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Department of Dermatology and Venereology, Academic Hospital, The Netherlands
- Age at study initiation: women – mean age = 39.9 years
Men- mean age = 46.6 years

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
other: White petrolatum
Concentration / amount:
2%
Day(s)/duration:
2 days
Adequacy of induction:
other: Patients with well established p-aminoazobenzene allergy were selected for the patch tests
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: White petrolatum
Concentration / amount:
2%
Day(s)/duration:
2 days
Adequacy of challenge:
not specified
No. of animals per dose:
32 patients (20 women and 12 men)
Details on study design:
A patch contain test chemical was placed in a small squares (about 1.0 cm2) and wetted with 1 drop of tap water, water was used to imitate the circumstances (wet hands or sweating of hands). By this procedure a slight but visible yellow stain on the skin was found at the test site after 2 days of application, indicating liberation of the dyes.
Challenge controls:
30 patients with an allergic contact dermatitis but negative to p-aminoazobenzene and PPD[para-phenylenediamine] were also tested with the same patch test series
Positive control substance(s):
not specified

Results and discussion

In vivo (non-LLNA)

Results
Reading:
1st reading
Hours after challenge:
72
Group:
test chemical
Dose level:
2%
No. with + reactions:
0
Total no. in group:
32
Clinical observations:
The chemical did not elicit a positive patch test reaction in any one of the 32 patients’ positive to p-aminoazobenzene nor in the 30 control subjects.
Remarks on result:
no indication of skin sensitisation

In vivo (LLNA)

Cellular proliferation data / Observations:
The chemical did not elicit a positive patch test reaction in any one of the 32 patients’ positive to p-aminoazobenzene nor in the 30 control subjects.

Applicant's summary and conclusion

Interpretation of results:
other: not sensitizing
Conclusions:
The test chemical did not elicit a positive patch test reaction in any of the 32 patients positive to p-aminoazobenzene, nor in the 30 control volunteers.
Hence, it can be considered to be not sensitizing to skin.
Executive summary:

A group of 32 patients with p-aminoazobenzene allergy were presumed that an increase in color printed newspapers might cause dermatitis. Patch tests were performed using the azo dyes in the printed papers along with specimens of the colored-printed newspaper. The test group consisted for 20 women and 12 men. 30 patients with an allergic contact dermatitis but negative to p-aminoazobenzene and PPD were also tested with the same patch test series.

The dyes were kindly provided by the firms Hoechst and Ciba-Geigy. To avoid false-negative reactions, a test concentration of 2% in white petrolatum was chosen. Patch tests were performed using uniform patches and following Standard procedures.

The test chemical did not elicit a positive patch test reaction in any of the 32 patients positive to p-aminoazobenzene, nor in the 30 control  volunteers.

Hence, it can be considered to be not sensitizing to skin.