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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:
key study
Study period:
2008-01-30 to 2008-04-21
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because the study was conducted similar to OECD 406 guidelines and is GLP compliant.
Justification for type of information:
A discussion and report on the read across strategy is given as an attachment in Section 13.
Cross-reference
Reason / purpose for cross-reference:
read-across: supporting information

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report date:
2008

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The study was conducted in accordance with OECD and EU test guidelines applicable at the time of undertaking.

Test material

Constituent 1
Reference substance name:
Alkenes, C20-24
IUPAC Name:
Alkenes, C20-24
Details on test material:
- Name of test material (as cited in study report): ENORDET O241
- Physical state: liquid, colourless
- Storage condition of test material: room temperature

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River (F-69592 L'Arbresle)
- Age at study initiation: four weeks
- Weight at study initiation: Between 347 to 271 grams
- Housing: groups of two or three in makrolon cages with woodflakes
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 23 degrees Celsius
- Humidity (%): 42 to 60%
- Air changes (per hr): at least ten changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light

IN-LIFE DATES: From: To: Not provided

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
other: olive oil and liquid paraffin
Concentration / amount:
Intradermal Induction: 100% of test material
Topical Induction: 100% of test material
Topical Challenge: 12.5 and 6.25% in liquid paraffin
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: olive oil and liquid paraffin
Concentration / amount:
Intradermal Induction: 100% of test material
Topical Induction: 100% of test material
Topical Challenge: 12.5 and 6.25% in liquid paraffin
No. of animals per dose:
Ten test animals and five control
Details on study design:
RANGE FINDING TESTS:

Yes. 2 animals intradermal induction, 2 animals topical induction, and 3 animals topical challenge.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 1 exposure
- Exposure period: 48 hours
- Test groups: 10 animals
- Control group: 5 animals
- Site: shoulder
- Frequency of applications: Single application
- Concentrations: 100% test material

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 1
- Exposure period: 24 hours
- Test groups: 10 animals
- Control group: 5 animals
- Site: left and right shorn flanks
- Concentrations:
- Evaluation (hr after challenge): Approximately 24 to 48 hours

OTHER: Test material concentration for the challenge phase was 12.5% in liquid paraffin for one side of the flank and 6.25% (v/v) in liquid paraffin on the opposite skin site on the shorn flank.
Challenge controls:
5 control animals.
Positive control substance(s):
not specified

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
other: Challenge
Hours after challenge:
24
Group:
test chemical
Dose level:
12.5%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: other: Challenge. . Hours after challenge: 24.0. Group: test group. Dose level: 12.5%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
other: Challenge
Hours after challenge:
48
Group:
test chemical
Dose level:
12.5%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: other: Challenge. . Hours after challenge: 48.0. Group: test group. Dose level: 12.5%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
other: Challenge
Hours after challenge:
24
Group:
test chemical
Dose level:
6.25%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: other: Challenge. . Hours after challenge: 24.0. Group: test group. Dose level: 6.25%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
other: Challenge
Hours after challenge:
48
Group:
test chemical
Dose level:
6.25%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: other: Challenge. . Hours after challenge: 48.0. Group: test group. Dose level: 6.25%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
other: Challenge
Hours after challenge:
24
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
other: Reading: other: Challenge. . Hours after challenge: 24.0. Group: negative control. Dose level: 0%. No with. + reactions: 0.0. Total no. in groups: 5.0.
Reading:
other: Challenge
Hours after challenge:
48
Group:
negative control
Dose level:
0%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
other: Reading: other: Challenge. . Hours after challenge: 48.0. Group: negative control. Dose level: 0%. No with. + reactions: 0.0. Total no. in groups: 5.0.

Applicant's summary and conclusion

Interpretation of results:
other: Not sensitising
Conclusions:
The study authors concluded that test material produced a 0% (0/10) skin sensitization rate in the female albino guinea pigs.
Executive summary:

In a guinea pig maximization skin test, concentrations for the main study were determined by “sighting tests” in which groups of guinea pigs were treated with various concentrations of test material.

 

Based on the outcome of the “sighting tests”, a group of 15 female guinea pigs were used in the main study with 10 serving as test animals and 5 as controls. In the induction phase, immediately before treatment, on day 0, the animals were clipped free of hair on the shoulder region and a row of three injections comprised of 0.1 mL Freund's Complete Adjuvant plus isotonic sodium chloride in the ratio 1:1, 100% of the test material, and a 50% formulation of the test material 1:1 preparation of Freund's Complete Adjuvant plus olive oil, on each side of the spine.A week later (day 7), the scapular region of all test and control animals was shaved and was brushed with a solution of sodium lauryl sulfate at 10% in thick vaseline, in order to create a local irritation. On Day 8 the same area on the shoulder region was previously for intradermal injetions was clipped again and treated with a topical application of the test material formulation. The topical application of the test material was 100% under occlusive dressing, which was kept in place for 48 hours. The degree of erythema and oedema was determined 24 hours later after the patches were removed using the Draize scale (1977).The induction of the control animals was performed identical to that used for the test animals except that the test material was omitted from the intradermal injections.

The challenge phase applied the test material formulation at 12.5% in liquid paraffin to the flanks of the each animal. The flanks were clipped free of hair. The test material was applied to one side of the shorn flank of each animal under occlusive dressing. To ensure that maximum non-irritant concentration was used in the challenge phase, the test material at a concentration of 6.25% (v/v) in liquid paraffin was also similarly applied to a separate skin site on the opposite shorn flank of the animals. These patches were also occluded to keep the test material in contact with the skin. After a 24 hour contact period, the dressing was carefully removed and the challenge sites were cleaned if required. Approximately 24, and 48 hours after removal of the challenge dressing, the degree of erythema and oedema was quantified using the Draize scale (1977). Any other toxicologically relevant reactions were also noted.

 

In the preliminary sighting tests no skin reactions were noted at the intradermal induction sites following treatment with the test material at concentrations of 100%, 50%, 25%, 12.5%, 6.25% and 3.125%. The concentration chosen for use in the Intradermal Induction phase of the main test was 100%. Well defined erythema was noted at the topical induction sites of the preliminary sighting test after treatment with 100% test material concentration. Slight erythema was noted at the test site for the 50% test material concentration as well as at 25% test material concentration. No skin reactions were noted at the topical induction sites for the 12.5% test concentration sites. No skin reactions were noted at the topical challenge sites of the preliminary sighting test animals following treatment with the test material at concentrations of 12.5%, 6.25%, 3.125% and 1.56%.

 

No skin reactions were noted at the topical challenge site of the 6.25% or 12.5% in liquid paraffin test or control group animals at the 24 and 48 -hour observations.

 

Following topical challenge, no skin reactions were noted at the challenge sites of the test or control animals at the 24 and 48 hour observation period. Animal body weight increases were comparable to those noted in the control group over the course of the study. Based on these results, the study authors concluded that test material produced a 0% (0/10) sensitization rate in the female albino guinea pigs.

 

This study received a Klimisch score of 1 and was classified as reliable without restriction because the study was conducted similar to OECD 406 testing guidelines and is GLP compliant.