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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:
2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
1992
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
study was conducted before the implementation of the LLNA

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Expiration date of the lot/batch: None provided
- Receipt date: February 7, 2000
- Appearance: White to offwhite granules
- storage: stored at room temperature.

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Hilltop Lab Animals, Inc., Scottdale, Pennsylvania
- Age at study initiation: nn
- Weight at study initiation: nn
- Housing: Cage cards displaying at least the study number, animal number and sex were affixed to each cage. The animals were housed individually in suspended stainless steel cages. All housing and care were based on the standards recommended by the Guide for the Care and Use of Laboratory Animals
- Diet (e.g. ad libitum): PMI Certified Guinea Pig Chow ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: 5d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-23
- Humidity (%): 32-60
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12

IN-LIFE DATES: 2.3.-3.4.2000

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal
Vehicle:
polyethylene glycol
Concentration / amount:
Injections for induction were as indicated below:
a. Injection Pair A: 0.1 mL of FCA emulsion
b. Injection Pair B: 0.1 mL of 1.0% test material in PEG 400
c. Injection Pair C: 0.1 mL of 1.0% test material/FCA emulsion
Challenge
Route:
intradermal and epicutaneous
Vehicle:
polyethylene glycol
Concentration / amount:
Injections for the challenge and rechallenge control animals were as indicated below:
a. Injection Pair A: 0.1 mL of FCA emulsion
b. Injection Pair B: 0.1 mL of PEG 400
c. Injection Pair C: 0.1 mL of 1.0% PEG 400/FCA emulsion
No. of animals per dose:
10
Details on study design:
Dermal Observations
The test sites at challenge were graded for dermal irritation at approximately 24 and 48 hours following chamber removal using the Dermal Grading System

Clinical Observations
Any unusual observations and mortality were recorded. The animals were observed for general health/mortality twice daily, once in the morning and once in the afternoon.

Body Weights
Individual body weights were obtained for all sensitization study animals on the day prior to intradermal induction (day -1) and for the test and challenge control animals on the day prior to challenge dosing. Final body weights were collected for all animals prior to euthanasia.

Scheduled Euthanasia
All sensitization study animals were euthanized by carbon dioxide inhalation following each animal's final scoring interval. Gross necropsy examinations were not required for these animals.
Challenge controls:
topical induction 0.8 ml PEG (solvent), challenge: 0.25g
Positive control substance(s):
yes
Remarks:
alpha-Hexylcinnamaldehyde

Results and discussion

Positive control results:
Using «-Hexylcinnamaldehyde as a positive control, Springbom Laboratories, Inc., Spencerville, Ohio, has completed a study during the past six months which provided historical control data for contact sensitization to this agent utilizing the test system described herein (Maximization Design). Following intradermal induction at 5.0% w/v alpha-Hexylcinnamaldehyde in propylene glycol, topical induction at 5.0% w/v alpha-Hexylcinnamaldehyde in propylene glycol and challenge at levels of 0.5% and 1.0% w/v «-Hexylcinnamaldehyde in propylene glycol, a contact sensitization response was observed, thereby demonstrating the susceptibility of the test system to this sensitizing agent.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
100%
No. with + reactions:
0
Total no. in group:
20
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
100%
No. with + reactions:
0
Total no. in group:
10

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
Based on the results of this study, the test substance is not considered to be a contact sensitizer in guinea pigs. The results of the alpha-Hexylcinnamaldehyde historical control study demonstrated that the test design utilized by Springbom Laboratories would detect potential contact sensitizers.
Executive summary:

The dermal sensitization potential of the test substance was evaluated in Harley-derived albino guinea pigs. Ten male and ten female guinea pigs received intradermal injections of 1.0 % w/v of the test substance in polyethylene glycol 400 (PEG 400) along with injections of FCA and the test substance in FCA. One week later, the test animals received a topical application of 100 % test substance. Challenge and rechallenge control animals received similar intradermal and topical treatments except PEG 400 was used in place of the test article. Following a two-week rest period, a challenge was performed whereby the twenty test and ten challenge control guinea pigs were topically treated with 100 % w/v test substance. Challenge responses in the test animals were compared with those of the challenge control animals. Following the challenge with 100 % test substance, dermal scores of 0 to +/- were noted in all test animals, while dermal scores of 0 were noted in all challenge control animals. Group mean dermal scores in the test animals were comparable to the challenge control animals. Using alpha-Hexylcinnamaldehyde as a positive control, the laboratory has completed a study during the past six months which provided historical control data for contact sensitization to this agent utilizing the test system described herein (Maximization Design). Following intradermal induction at 5.0 % w/v alpha-Hexylcinnamaldehyde in propylene glycol, topical induction at 5.0 % w/v alpha-Hexylcinnamaldehyde in propylene glycol and challenge at levels of 0.5 % and 1.0 % w/v alpha-Hexylcinnamaldehyde in propylene glycol, a contact sensitization response was observed, thereby demonstrating the susceptibility of the test system to this sensitizing agent. Based on the results of this study, the test substance is not considered to be a contact sensitizer in guinea pigs. The results of the alpha-Hexylcinnamaldehyde historical control study demonstrated that the test design utilized by Springborn Laboratories would detect potential contact sensitizers.