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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:
key study
Study period:
21 January 1991 - 7 March 1991
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
Buehler test
Justification for non-LLNA method:
The Murine Local Lymph Node Assay (LLNA) is the first-choice method for in vivo testing according to the REACH Regulation. However, this test was performed before entry into force of the REACH Regulation.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
- Name of test material (as cited in study report): 6398-24-1, Project #90-018
- Substance type: clear colorless liquid
- Physical state: liquid
- Analytical purity: responsibility of the sponsor
- Stability under test conditions: no apparent change in the physical appearance of the test article during administration
- Storage condition of test material: responsibility of the sponsor

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Buckberg Lab Animals, Tomkins Cove, New York
- Weight at study initiation: 300-700 g
- Age at study initiation: no data
- Housing: individually in wire mesh cages
- Diet (e.g. ad libitum): purina guinea pig diet, ad libitum
- Water (e.g. ad libitum): fresh tap water, ad libitum
- Acclimation period: minimum 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 3°C
- Humidity (%): 30-70 %
- Photoperiod (hrs dark / hrs light): 12 hrs dark / 12 hrs light

Study design: in vivo (non-LLNA)

Induction
Route:
epicutaneous, occlusive
Vehicle:
other: 80% ethanol (inductions) and acetone (challenge)
Concentration / amount:
Volume administered: 0.3 ml/dose
Induction: 5.0% (v/v); challenge: 5.0% (v/v)
Challenge
Route:
epicutaneous, occlusive
Vehicle:
other: 80% ethanol (inductions) and acetone (challenge)
Concentration / amount:
Volume administered: 0.3 ml/dose
Induction: 5.0% (v/v); challenge: 5.0% (v/v)
No. of animals per dose:
dose range: 8 (4 males, 4 females);
test article: 20 (10 males, 10 females);
positive control: 5 (2 males, 3 females);
negative control: 10 (5 males, 5 females)
Details on study design:
RANGE FINDING TESTS:
8 animals (4 males, 4 females) were each exposed to 4 concentrations of the test material in either 80% ethanol (test concentrations of 1, 10, 50 and 100%) or acetone (test concentrations of 1.0, 2.5, 5.0 and 10%)
Primary irritation responses were graded after 24h as follows:
0 = no reaction
+ = slighly patchy erythema
1 = slight of confluent or moderate patchy erythema
2 = moderate erythema
3 = severe erythema with/without edema
The highest non-irritatting concentration was that concentration in the vehicle that induced responses not exceeding two + and two 0 grades in the group of 4 animals.
Based upon the results of the dose-range-finding studies and in discussion with the sponsor, the test article was dosed at 5.0% in 80% ethanol for induction and at 5.0% in acetone for challenge.


MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3 inductions
- Exposure period: Once a week for three weeks, a total of three six-hour inductions.
- Test groups: test substance in vehicle (80% ethanol)
- Control group: vehicle only
- Site: left shoulder
- Frequency of applications: once a week
- Duration: 6 h
- Concentrations: 5.0%


B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 14 days after the last induction sensitizing exposure
- Test groups: test substance in vehicle (acetone)
- Control group: vehicle only (left flank), test article (right flank)
- Site: naive site on left side
- Concentrations: 5.0%
- Evaluation (hr after challenge): 24 and 48h


OTHER:
24h after challenge, all animals were depilated with Neet Cream Hair Remover (Whitehall Laboratories, Inc., New York). A minimum of 2h after depilation, test sites were graded.
Challenge controls:
The negative control group was challenged with vehicle (acetone) on the left flank.
Positive control substance(s):
yes
Remarks:
1-chloro-2,4-dinitrobenzene (0.3%)

Results and discussion

Positive control results:
A positive response was elicited in the animals receiving the positive control article, 1-chloro-2,4-dinitrobenezen (DNCB)

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
5.0%
No. with + reactions:
3
Total no. in group:
20
Clinical observations:
severity= 0.5
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
5.0%
No. with + reactions:
6
Total no. in group:
20
Clinical observations:
severity= 0.7
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
0.3%
No. with + reactions:
5
Total no. in group:
5
Clinical observations:
severity= 3.0
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
0.3%
No. with + reactions:
5
Total no. in group:
5
Clinical observations:
severity= 3.0
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
vehicle (acetone)
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
severity= 0.0
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
vehicle (acetone)
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
severity= 0.0
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
other: naive control
Dose level:
5.0% test article
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
severity= 0.1
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
other: naive control
Dose level:
5.0% test article
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
severity= 0.1

Any other information on results incl. tables

Results dose-range finding test:

Vehicle 80% ethanol: 1.0% dose caused no reaction, 10% dose caused slightly patchy erythema (1/4), slight or confluent or moderate patchy erythema (2/4) and severe erythema (1/4), 50% and 100% doses caused severe erythema.

Vehicle acetone: 1.0% and 2.5% doses caused no reaction, 5.0% dose caused no reaction (1/4) and slightly patchy erythema (3/4), 10% dose caused no reaction (2/4), slightly patchy erythema (1/4) and severe erythema (1/4).

The highest non-irritating dose (max. two animals with slightly patchy erythema) for challenge exposure was chosen to be 5% in acetone. The highest dose to cause mild irritation for induction exposure was chosen to be 5% in 80% ethanol.

Applicant's summary and conclusion

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
Based upon the observations made in the assay, the substance induced and challenged at a 5.0% concentration caused delayed contact hypersensitivity in guinea pigs.