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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:
Between 05 July and 01 September 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to GLP in accordance with recognised guideline

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Strain: CBA/Ca (CBA/CaOlaHsd)
- Source: Harlan UK Limited, Bicester, Oxon, UK
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 15-23 g
- Housing: Individually housed in suspended solid floor polypropylene cages furnished with softwood flakes.
- Diet (e.g. ad libitum): 2014 Teklad global rodent diet, ad libitum
- Water (e.g. ad libitum):mains tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 °C
- Humidity (%): 30-70 %
- Air changes (per hr): at least 15 changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours continuous light/dark cycle

IN-LIFE DATES: No data available

Study design: in vivo (LLNA)

Vehicle:
acetone/olive oil (4:1 v/v)
Concentration:
CONCS: 25%, 2.5%, and 0.25 v/v
No. of animals per dose:
5 mice per dose.
Details on study design:
TREATMENT PREPARATION AND ADMINISTRATION:

RANGE FINDING TESTS:
- Compound solubility: the vehicle was based on trail formulations. Homogeneity was obtained to visually acceptable levels.
- Irritation: At a 100% test substance concentration mild redness to the neck and ears was noted. The highest test substance concentration selected for the main study was a 25% concentration.
- Lymph node proliferation response: Expressed as the number of radioactive disintegrations per minute per lymph nodes from each individual animal and as the ration of ^3HTdR incorporation into lymph node cells of test nodes relative to that recorded for the control nodes (Stimulation Index).


MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: “Skin Sensitisation: Local Lymph Node Assay”
- Criteria used to consider a positive response: 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.


TREATMENT PREPARATION AND ADMINISTRATION:
The dorsal surface of both ears was epidermally treated (. 25 µl/ear). The concentrations were mixed thoroughly using a vortex mixer immediately prior to dosing. The application was repeated on days 2 and 3. On day 6 an injection of 250 µl phosphate buffered saline (PBS) containing 20 µCi of 3H-methyl thymidine (3H-TdR) was made into the tail vein of each experimental mouse. Five hours later, the draining Auricular lymph node of each ear was excised into PBS. The relative size of the nodes and surrounding area were recorded. The nodes were pooled for each animal in approximately 4mL PBS. A single cell suspension of lymph node cells (LNC) was prepared in PBS by gentle separation through stainless steel gauze. LNC were washed twice with an excess of PBS by centifugation at 190g for 10 minutes at 4C. To precipitate the DNA, the LNC were exposed to 5% trichloroacetic acid (TCA) at 4 C during the night.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:
Concentration v/v in acetone/olive oil 4:1 = 25 %
Stimulation Index: 7.25
Result: Positive

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: Concentration SI vehicle control: N/A 0.25%: 3.05 2.5%: 13.78 25%: 12.54
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Concentration Mean dpm/animal vehicle control: 2576 0.25%: 7845 2.5%: 35504 25%: 32307

Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information
Conclusions:
The test material was considered to be a sensitiser under the conditions of the test.
Executive summary:

A study was performed to assess the skin sensitization potential of the testmaterial in the CBA/Ca strain mouse following topical application to the dorsal surface of the ear according to OECD Guideline No. 429 "Skin Sensitization: Local Lymph Node Assay" (adopted 24 April 2002), Method B42 Skin Sensitization (Local Lymph Node Assay) of Commission Directive 2004/73/EC, and United States Environmental Protection Agency Health Effects Test Guidelines OPPTS 870.2600 Skin Sensitization March, 2003.Followingapreliminaryscreening test, 25% v/vconcentration was selected as the highest dose investigated in the main test of the Local Lymph Node Assay. Three groups, each of five animals, were treated with 50 ul (25 ul per ear) of the test material as a solution in acetone/olive oil 4:1 at concentrations of 25%, 2.5% or 0.25% v/v. A further group of five animals was treated with acetone/olive oil 4:1 alone. The Stimulation index were 3.05, 13.78 and 12.54 for 0.25%, 2.5% and 25% groups, respectively. The results of this studysupported the conclusion that the test substance is askin sensitizer.