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Toxicological information

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:
Experimental study on skin sensitization potencies and cross-reactivities of hair-dye-related chemicals in guinea pigs
Author:
Zhenlin Xie et.al
Year:
2000
Bibliographic source:
Contact Dermatitis

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Magnusson & Kligman guinea pig maximization test (GPMT)
Principles of method if other than guideline:
To evaluate skin sensitization potential of the test chemical on guinea pigs
GLP compliance:
not specified
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
- Name of test material : 1-(4-(phenylazo)phenylazo)-2-naphthol
- Molecular formula : C22H16N4O
- Molecular weight : 352.3954 g/mol
-Smiles:c12c(\N=N\c3ccc(\N=N\c4ccccc4)cc3)c(ccc1cccc2)O
-InChI:1S/C22H16N4O/c27-21-15-10-16-6-4-5-9-20(16)22(21)26-25-19-13-11-18(12-14-19)24-23-17-7-2-1-3-8-17/h1-15,27H/b24-23+,26-25+
- Substance type: organic
- Physical state: solid powder
- Purity: 99%
- Impurities : approx 1%

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Nippon Bio Supp. Center, Tokyo
- Age at study initiation: 4 weeks
- Weight at study initiation: 300 – 350 g
- Housing: housed in groups of 3 in stainless steel wire-mesh cages
- Diet (e.g. ad libitum): solid diet ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 1 week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22± 2°C
- Humidity (%): 55±5%
- Air changes (per hr): 15x/h
- Photoperiod (hrs dark / hrs light): 12 h daily

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
olive oil
Concentration / amount:
(1) 0.1 ml emulsified mixture of Freund’s complete adjuvant and saline (1:1);
(2) 0.1 ml of 0.1% chemicals in olive oil
(3) 0.1 ml of the 0.1% test substance in FCA and saline mixture (1:1).
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Route:
epicutaneous, occlusive
Vehicle:
petrolatum
Concentration / amount:
0.5 g of 1.0% test chemicals in petrolatum
Day(s)/duration:
48 hours
Adequacy of induction:
non-irritant substance, but skin pre-treated with 10% SDS
Challenge
No.:
#1
Route:
epicutaneous, open
Vehicle:
other: acetone
Concentration / amount:
0.03 ml
Day(s)/duration:
72 hours
Adequacy of challenge:
other: the highest soluble concentrations were used
No. of animals per dose:
Total=6
Details on study design:
MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3 injections
- Exposure period: no data
- Test groups: 6 animals
- Control group: not specified
- Site: 2x4 cm clipped neck
- Frequency of applications: not specified
- Duration: not specified
- Concentrations: 0.1 ml of 0.1% test material

B. INDUCTION EXPOSURE
- No. of exposures: not specified
- Day(s) of induction: on day 7
- Exposure period: 48 hrs
- Test groups: 6 animals
- Control group: not specified
- Site: 2x4 cm clipped neck

- Concentrations: 0.5 g of 1.0% test chemical

C. CHALLENGE EXPOSURE
- No. of exposures: not specified
- Day(s) of challenge: 1
- Exposure period: 72 hrs
- Test groups: 6 animals
- Control group: not specified
- Site: flank regions
- Concentrations: 0.03 ml in acetone
- Evaluation (hr after challenge): 48 h


OTHER: In order to enhance the sensitization, sodium lauryl sulfate 10% in petrolatum was applied on induction area for 24 h before the topical induction.
Challenge controls:
vehicle control used
Positive control substance(s):
not specified

Results and discussion

In vivo (non-LLNA)

Results
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
0.03 ml in acetone
No. with + reactions:
0
Total no. in group:
6
Clinical observations:
In Sudan III-induced animals, no positive reaction was elicited at 0.1% concentrations
Remarks on result:
no indication of skin sensitisation

In vivo (LLNA)

Cellular proliferation data / Observations:
No positive reaction was elicited at 0.1% concentrations

Applicant's summary and conclusion

Interpretation of results:
other: Not sensitizing
Conclusions:
The skin sensitization potential of the test chemical was evaluated on 6 Female Hartley strain albino guinea pigs.
No positive reaction was elicited at the concentrations tested. Hence, the test chemical was considered to be not sensitizing to guinea pig’s skin.
Executive summary:

Magnusson & Kligman guinea pig maximization test (GPMT) was conducted on six Female Hartley strain albino guinea pigs to assess the dermal sensitization potential of the test chemical.

Induction treatment consisted of 3 intra-dermal injections and one topical induction. On day 0, a row of 3 injections of 0.1 ml test material emulsified mixture of Freund’s complete adjuvant and saline (1:1) in olive oil was given on each side of the 2x4 cm clipped neck . In order to enhance the sensitization, sodium lauryl sulfate 10% in petrolatum was applied on induction area for 24 h before the topical induction. On day 7, 0.5 g of 1.0% test chemicals in petrolatum were occlusively applied for 48 h. The samples were covered with lint pads which were lining with Blenderm tape.

The challenge treatment was given by open topical application. On day 21, the flank regions of the animals were clipped and shaved, and then 0.03 ml of test material in acetone was applied to the skin for 72 hrs. Observations were made 48 hrs after challenge. No positive reaction was elicited at the concentrations tested.

Hence, the test chemical was considered to be not sensitizing to guinea pig’s skin.