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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
Further information is included under 'Attached justification' in IUCLID section 13 and 'Cross-reference'.
Cross-reference
Reason / purpose:
read-across: supporting information
Reference
Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
Further information is included under 'Attached justification' in IUCLID section 13 and 'Cross-reference'.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
1992
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Version / remarks:
1996
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Version / remarks:
2003
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Done in conjunction with the LLNA method
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source/batch No.of test material:
Sigma-Aldrich, Munich, Germany / Aldrich No. L1376
- Purity: 99%
Species:
guinea pig
Strain:
other: SPF-Hsd Poc: DH
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source:
Harlan Winkelmann, Borchen, Germany
- Females nulliparous and non-pregnant: yes
- Microbiological status of animals, when known:
SPF
- Weight at study initiation:
300 - 500 grams
- Housing:
Terluran cages on Altromin saw fiber bedding or Lignocel bedding
- Diet (e.g. ad libitum):
Ad libitum
- Water (e.g. ad libitum):
Ad libitum
- Acclimation period:
At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 55 ± 10
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 / 12
Route:
intradermal
Vehicle:
other: 1:1 (v/v) mixture of FCA/physiological saline
Concentration / amount:
5%
Day(s)/duration:
Day 0
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
other: Vaseline
Concentration / amount:
100%
Day(s)/duration:
Day 7 / 48 hours
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: Vaseline
Concentration / amount:
50%
Day(s)/duration:
Day 20 / 24 hours
Adequacy of challenge:
not specified
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
other: Vaseline
Concentration / amount:
50%
Day(s)/duration:
Day 28 / 24 hours
Adequacy of challenge:
not specified
No. of animals per dose:
10 test animals and 5 control animals
Details on study design:
RANGE FINDING TESTS: Performed in a preliminary experiment assessing the irritant effects of the test compound after intradermal and topical application

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: Day 0 and Day 7 (48 hours)
- Test groups: One test group exposed to linoleic acid
- Control group: One control group exposed to vehicle only
- Frequency of applications: Once
- Duration: Day 0 to Day 20
- Concentrations: Intradermal induction - 5%; Topical induction - 100%

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: 20 and 28
- Exposure period: 24 hours
- Test groups: One test group exposed to linoleic acid
- Control group: One control group exposed to vehicle only
- Concentrations: 50%
- Evaluation (hr after challenge): 24, 48 and 72 hours
Challenge controls:
Vehicle only
Positive control substance(s):
not specified
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
2
Total no. in group:
10
Remarks on result:
not determinable
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
50%
No. with + reactions:
1
Total no. in group:
10
Remarks on result:
not determinable
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
not determinable
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
4
Total no. in group:
10
Remarks on result:
not determinable
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
50%
No. with + reactions:
3
Total no. in group:
10
Remarks on result:
not determinable
Reading:
rechallenge
Hours after challenge:
72
Group:
test group
Dose level:
50%
No. with + reactions:
2
Total no. in group:
10
Remarks on result:
not determinable
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100%
Remarks on result:
other: Not reported.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100%
No. with + reactions:
1
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
100%
Remarks on result:
other: Not reported.
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Remarks on result:
not measured/tested
Reading:
rechallenge
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested

After challenge and re-challenge with linoleic acid, skin reactions were observed in the control group as frequently or even at a higher incidence than the test group. Therefore, it was concluded that the test concentration was too high and included irritative reactions and no conclusion regarding skin sensitization could be drawn.

Interpretation of results:
other: Data inconclusive
Conclusions:
Due to non-specific irritative skin reactions observed, it was concluded that the challenge test concentration was too high, and no conclusion in regard to skin sensitization could be made.
Executive summary:

Female SPF-Hsd Poc: DH guinea pigs, weighing between 300 and 500 grams, were obtained for this guinea pig maximisation test (GPMT). The guinea pigs were divided into 2 groups, a negative control group containing 5 guinea pigs, and a test group containing 10 guinea pigs. The animals recieved two induction treatments, an intradermal injection (day 0) and a topical application (day 7). The test concentrations used for the two induction tests were 5% linoleic acid for the intradermal induction and 100% linoleic acid for the topical induction. The animals also recieved two topical challenge treatments, one on day 20 and one on day 28. The test concentration used for the two challenge tests was 50% linoleic acid. Isotonic saline was used as the vehicle for the intradermal injection and vaseline was used as the vehicle for the topical exposures, and control animals were dosed with the vehicle alone. After challenge and re-challenge with linoleic acid, skin reactions were observed in the control group as frequently or even at a higher incidence than the test group. Therefore, it was concluded that the test concentration was too high and included irritative reactions and therefore no conclusion regarding skin sensitization could be drawn.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
1992
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Version / remarks:
1996
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
Version / remarks:
2003
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
Done in conjunction with the LLNA method

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source/batch No.of test material:
Sigma-Aldrich, Munich, Germany / Aldrich No. L1376
- Purity: 99%

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: SPF-Hsd Poc: DH
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source:
Harlan Winkelmann, Borchen, Germany
- Females nulliparous and non-pregnant: yes
- Microbiological status of animals, when known:
SPF
- Weight at study initiation:
300 - 500 grams
- Housing:
Terluran cages on Altromin saw fiber bedding or Lignocel bedding
- Diet (e.g. ad libitum):
Ad libitum
- Water (e.g. ad libitum):
Ad libitum
- Acclimation period:
At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 55 ± 10
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 / 12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
other: 1:1 (v/v) mixture of FCA/physiological saline
Concentration / amount:
5%
Day(s)/duration:
Day 0
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
epicutaneous, occlusive
Vehicle:
other: Vaseline
Concentration / amount:
100%
Day(s)/duration:
Day 7 / 48 hours
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challengeopen allclose all
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: Vaseline
Concentration / amount:
50%
Day(s)/duration:
Day 20 / 24 hours
Adequacy of challenge:
not specified
No.:
#2
Route:
epicutaneous, occlusive
Vehicle:
other: Vaseline
Concentration / amount:
50%
Day(s)/duration:
Day 28 / 24 hours
Adequacy of challenge:
not specified
No. of animals per dose:
10 test animals and 5 control animals
Details on study design:
RANGE FINDING TESTS: Performed in a preliminary experiment assessing the irritant effects of the test compound after intradermal and topical application

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2
- Exposure period: Day 0 and Day 7 (48 hours)
- Test groups: One test group exposed to linoleic acid
- Control group: One control group exposed to vehicle only
- Frequency of applications: Once
- Duration: Day 0 to Day 20
- Concentrations: Intradermal induction - 5%; Topical induction - 100%

B. CHALLENGE EXPOSURE
- No. of exposures: 2
- Day(s) of challenge: 20 and 28
- Exposure period: 24 hours
- Test groups: One test group exposed to linoleic acid
- Control group: One control group exposed to vehicle only
- Concentrations: 50%
- Evaluation (hr after challenge): 24, 48 and 72 hours
Challenge controls:
Vehicle only
Positive control substance(s):
not specified

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
2
Total no. in group:
10
Remarks on result:
not determinable
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
50%
No. with + reactions:
1
Total no. in group:
10
Remarks on result:
not determinable
Reading:
other: 3rd reading
Hours after challenge:
72
Group:
test group
Dose level:
50%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
not determinable
Reading:
rechallenge
Hours after challenge:
24
Group:
test group
Dose level:
50%
No. with + reactions:
4
Total no. in group:
10
Remarks on result:
not determinable
Reading:
rechallenge
Hours after challenge:
48
Group:
test group
Dose level:
50%
No. with + reactions:
3
Total no. in group:
10
Remarks on result:
not determinable
Reading:
rechallenge
Hours after challenge:
72
Group:
test group
Dose level:
50%
No. with + reactions:
2
Total no. in group:
10
Remarks on result:
not determinable
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100%
Remarks on result:
other: Not reported.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100%
No. with + reactions:
1
Total no. in group:
10
Reading:
rechallenge
Hours after challenge:
24
Group:
negative control
Dose level:
100%
Remarks on result:
other: Not reported.
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Remarks on result:
not measured/tested
Reading:
rechallenge
Hours after challenge:
24
Group:
positive control
Remarks on result:
not measured/tested

Any other information on results incl. tables

After challenge and re-challenge with linoleic acid, skin reactions were observed in the control group as frequently or even at a higher incidence than the test group. Therefore, it was concluded that the test concentration was too high and included irritative reactions and no conclusion regarding skin sensitization could be drawn.

Applicant's summary and conclusion

Interpretation of results:
other: Data inconclusive
Conclusions:
Due to non-specific irritative skin reactions observed, it was concluded that the challenge test concentration was too high, and no conclusion in regard to skin sensitization could be made.
Executive summary:

Female SPF-Hsd Poc: DH guinea pigs, weighing between 300 and 500 grams, were obtained for this guinea pig maximisation test (GPMT). The guinea pigs were divided into 2 groups, a negative control group containing 5 guinea pigs, and a test group containing 10 guinea pigs. The animals recieved two induction treatments, an intradermal injection (day 0) and a topical application (day 7). The test concentrations used for the two induction tests were 5% linoleic acid for the intradermal induction and 100% linoleic acid for the topical induction. The animals also recieved two topical challenge treatments, one on day 20 and one on day 28. The test concentration used for the two challenge tests was 50% linoleic acid. Isotonic saline was used as the vehicle for the intradermal injection and vaseline was used as the vehicle for the topical exposures, and control animals were dosed with the vehicle alone. After challenge and re-challenge with linoleic acid, skin reactions were observed in the control group as frequently or even at a higher incidence than the test group. Therefore, it was concluded that the test concentration was too high and included irritative reactions and therefore no conclusion regarding skin sensitization could be drawn.