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Toxicological information

Skin sensitisation

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Administrative data

Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 October 2009 to 11 November 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories UK Limited, Bicester, Oxon, UK.
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 15-23 g
- Housing: Suspended solid floor polypropylene cages furnished with softwood 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): 19-25 °C
- Humidity (%): 30-70%
- Air changes (per hr): ca. 15
- Photoperiod (hrs dark / hrs light): 12 hours dark/12 hours light

IN-LIFE DATES: Not stated.

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
50% and 25% v/v
No. of animals per dose:
4
Details on study design:
RANGE FINDING TESTS:
- Compound solubility:
For the purpose of the study, the test material was freshly prepared as a solution in acetone/olive oil 4:1. This vehicle was chosen as it produced the most suitable formulation at the required concentration.
- Irritation:
Using available information regarding the systemic toxicity/irritancy potential of the test material, a preliminary screening test was performed using one mouse. The mouse was treated by daily application of 25 µI of the undiluted test material to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The mouse was observed twice daily on Days 1, 2 and 3 and once daily on Days 4, 5 and 6. Any signs of toxicity or excessive local irritation noted during this period were recorded. The bodyweight was recorded on Day 1 (prior to dosing) and on Day 6.
No signs of systemic toxicity were noted.
Based on this information, the undiluted test material and the test material at concentrations of 50% and 25% v/v in acetone/olive oil 4:1 were selected for the main test.


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: Skin Sensitisation: Local Lymph Node Assay
- Criteria used to consider a positive response:
The proliferation response of lymph node cells was expressed as the number of radioactive disintegrations per minute per lymph node (disintegrations per minute/node) and as the ratio of 3HTdR incorporation into lymph node cells of test nodes relative to that recorded for the control nodes (Stimulation Index).
The test material will be regarded as a sensitiser if at least one concentration of the test material results in a threefold or greater increase in 3HTdR incorporation compared to control values. Any test material failing to produce a threefold or greater increase in 3HTdR incorporation will be classified as a "non sensitiser".


TREATMENT PREPARATION AND ADMINISTRATION:
Main test:
Groups of four mice were treated with the test material at a concentration of 50 % or 25% w/w in acetone/olive oil 4:1. The preliminary screening test suggested that the test material would not produce systemic toxicity or excessive local irritation at the highest suitable concentration. The mice were treated by daily application of 25 µl of the appropriate concentration of the test material to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The test material formulation was administered using an automatic micropipette and spread over the dorsal surface of the ear using the tip of the pipette.
A further group of four mice received the vehicle alone in the same manner.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
The proliferation response of lymph node cells was expressed as the number of radioactive disintegrations per minute per lymph node (disintegrations per minute/node) and as the ratio of 3HTdR incorporation into lymph node cells of test nodes relative to that recorded for the control nodes (Stimulation Index).
The test material will be regarded as a sensitiser if at least one concentration of the test material results in a threefold or greater increase in 3HTdR incorporation compared to control values. Any test material failing to produce a threefold or greater increase in 3HTdR incorporation will be classified as a "non sensitiser".

Results and discussion

Positive control results:
The Stimulation Index expressed as the mean radioactive incorporation for the treatment group divided by the mean radioactive incorporation of the vehicle control group is as follows:

Concentration (% v/v) in
acetone/olive oil 4:1 Stimulation Index Result
15 3.70 Positive

alpha-Hexylcinnamaldehyde was considered to be a sensitiser under the conditions of the test.

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Value:
1.05
Remarks on result:
other: 25%
Parameter:
SI
Value:
2.42
Remarks on result:
other: 50%
Parameter:
SI
Value:
2.6
Remarks on result:
other: 100

Any other information on results incl. tables

Concentration (% v/v) in acetone/olive oil 4:1

Disintegrations per Minute (dpm)

Disintegrations per Minute/Node (dpm/Node)

Vehicle

9169.45

1146.18

25

9593.81

1199.23

50

22233.46

2779.18

100

23859.52

2982.44

There were no deaths. No signs of systemic toxicity were noted in the test or control animals during the test.

Bodyweight changes of the test animals between Day 1 and Day 6 were comparable to those observed in the corresponding control group animals over the same period.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
The test material was considered to be a non-sensitiser under the conditions of the test.
Executive summary:

The test material was considered to be a non-sensitiser under the conditions of a Local Lymph Node Assay conducted in accordance with OECD guideline 429.