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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
Remarks:
The test substance (Citronellal; CAS 106-23-0) represents the racemate of the registered substance (R)-3,7-dimethyloct-6-enal (CAS 2385-77-5).
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study according to guideline, GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Qualifier:
according to
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): citronellal FH
- Physical state: liquid
- Analytical purity: 98.7 %
- Lot/batch No.: 602790
- Storage condition of test material: room temperature and protected from light

In vivo test system

Test animals

Species:
mouse
Strain:
CBA
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Jackson Laboratories, Bar Harbor, ME
- Age at study initiation: 11 weeks
- Weight at study initiation: 18-25 g
- Fasting period before study: none
- Housing: 5 animals per cage
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 6 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.1-26.7°C
- Humidity (%): 30-53%
- Photoperiod (hrs dark / hrs light): 12/12 hours

Study design: in vivo (LLNA)

Vehicle:
other: diethyl phthalate/ethanol in a ratio of 3:1
Concentration:
7.5%, 15%, or 30% (v/v) with the vehicle; test concentrations chosen as typical concentrations in fragrances
No. of animals per dose:
5
Details on study design:
MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: The criterion for a positive response is that one or more concentrations of a test material elicits a 3-fold or greater increase in incorporation of 3H-thymidine relative to the vehicle control.


TREATMENT PREPARATION AND ADMINISTRATION: 25 µl administered topically to the dorsum of each ear lobe (left and right) once per day for three consecutive days. Three days after the third topical application (Day 6) all mice were injected intravenously into a tail vein with 250 µl of sterile saline containing approximately 20 µCi [3]H-thymidine. Five hours after the intravenous injection, the animals were sacrificed. Ear thickness measurements of each mouse were recorded and the draining auricular lymph nodes removed. 3H-thymidine incorporation was measured in single cell suspensions of lymph node cells.
Clinical observations: daily, and prior and after application of test substance
Body weight: day 1 and day 6
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
The evaluation of the equality of means for the DPM, body weight and ear thickness data was made by a one-way analysis of variance using the F distribution to assess statistical significance. If statistically significant differences between the means were found, a Dunnett's test was used to determine the degree of significance from the control means

Results and discussion

In vivo (LLNA)

Resultsopen allclose all
Parameter:
SI
Remarks on result:
other: 7.5, 15, 30 % citronellal: SI = 1.28, 1.57, 1.50 positive control (35% hexylcinnamaldehyde): SI=6.27
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: 7.5, 15, and 30% citronellal: 226, 277, 264 vehicle control: 176 positive control: 1103

Any other information on results incl. tables

Table: Measurements of ear thickness

Test group

Concentration

Ear thickness (mm)

Vehicle control

0.315

Citronellal

7.5 %

0.317

15 %

0.314

30 %

0.311

Positive control

0.347 *

* significant increase compared to vehicle control, p<0.001

Applicant's summary and conclusion