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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well-documented publication comparable to guideline study

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Investigation of the Dermal Sensitization Potential of Various Essential Oils in the Local Lymph Node Assay.
Author:
Lalko J, Api AM
Year:
2006
Bibliographic source:
Food and Chemical Toxicology 44: 739-746
Reference Type:
secondary source
Title:
No information
Author:
Lalko J, Api AM
Year:
2008
Bibliographic source:
RIFM database

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
GLP compliance:
not specified
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Geraniol
- Analytical purity: 98.5 %

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Interfauna UK, Shaw's Farm, Blackthorne, Bicester, Oxon, UK
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 17 - 21 g
- Housing: groups of 4 per cage
- Diet (e.g. ad libitum): ad libitum, Porton combined Diet, pelleted diet; Special Diets Services Ltd., Witham, UK
- Water (e.g. ad libitum): ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12 / 12

The study described herein was performed in accordance with the Animals (Scientific Procedures) Act 1986 as detailed in the guidance provided by the Home Office (2000).

Study design: in vivo (LLNA)

Vehicle:
other: ethanol : diethyl phthalate, 1:3
Concentration:
2.5%, 5%, 10%, 25%, 50% w/v.
No. of animals per dose:
4
Details on study design:
MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: A material was considered a sensitizer if at least one concentration of the test material was observed to have a stimulation index (SI) value of 3 or more. The SI value for each test material was calculated by dividing the mean dpm (disintegrations per minute) at a given dose level by the mean dpm of the vehicle control group.


TREATMENT PREPARATION AND ADMINISTRATION:
Mice were dosed topically on the dorsum of both ears with 25 µl of Geraniol. Each group received one concentration.
A control group was similary treated with 1:3 Ethanol:Diethylphtalate. Dosing occured daily for three consecutive days.
After two days of "rest" all mice were injected intravenously by the tail vein with 250 µl of phosphate buffered saline containing 20 µCi of [3 H] methyl thymidine (3HTdR; specific activity 2.0 Ci/mmol, Amersham Pharmacia Biotech UK Limited, UK).
Five hours later, the mice were euthanized and the draining auricular lymph nodes were excised and pooled for each experimental group.
Suspensions of the lymph node cells (LNC)were prepared by mechanical disaggregation through 200-mesh stainless steel gauze.
The cell suspensions were washed three times with phosphate buffered saline (PBS) and precipitated overnight at 4 °C with 5% wlv trichloroacetic acid (TCA). The samples were then pelleted by centrifugation.
The cells were resuspended in 1 ml of TCA and transferred to scintillation vials containing 10 ml of scintillation fluid (Optiphase MP, LKB).
The incorporation of 3HTdR was measured by beta-scintillation counting and expressed as disintegrations per minute (dpm) per lymph node for each experimental group.
Statistics:
For each concentration of test material, a stimulation index (SI) relative to the concurrent vehicle-treated control was calculated.
The EC3 value, or estimated concentration of test material required to elicit an SI of 3 or more, was derived from the dose-response data by linear interpolation.
This value was taken as a measure of relative sensitization potential for each material. Using two data points on the dose response curve, one immediately above and one below the SI value of three, the EC3 value was calculated using the equation from Basketter et al. (1999).

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: 2.5%: 1.7 5%: 2.4 10%: 2.8 25%: 4.8 50%: 6.0
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: vehicle control: 330 2.5%: 574 5%: 800 10%: 926 25%: 1582 50%: 2000

Any other information on results incl. tables

RS-Freetext:
Test concentrations [% w/v] / DPM/lymph node / SI /
-----------------------------------------------------------
1:3 EtOH:DEP (vehicle) / 330 / N/A /
2.5 / 574 / 1.7 /
5.0 / 800 / 2.4 /
10.0 / 926 / 2.8 /
25.0 / 1582 / 4.8 /
50.0 / 2000 / 6.0 /
-----------------------------------------------------------
EC3 = 11.4 %
-----------------------------------------------------------
N/A: not applicable
EtOH: ethanol
DEP: Diethyl phthalate

dpm/lymph node: mean desintegrations per minute per lymph node for nodes pooled from each dose group of 4 mice

SI: Stimulation index values >/= 3 are considered to result in a positive response

EC3: The estimated concentration giving rise to a stimulation index of 3 was calculated by linear interpretation of the dose response data for each assay according to Basketter et al. (1999). The lower the EC3 value, the greater the skin sensitization potential.


Applicant's summary and conclusion

Interpretation of results:
sensitising
Remarks:
Migrated information