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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes
Type of study:
mouse local lymphnode assay (LLNA)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Details on test material:
- Purity: 99.2%

In vivo test system

Test animals

Species:
mouse
Strain:
other: CBA/JHsd
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Sprague Dawley, Frederick, Maryland, U.S.A.
- Females (if applicable) nulliparous and non-pregnant: not specified
- Age at study initiation: approximately 9 weeks old
- Weight at study initiation: weighed between 20.7 and 23.5 grams
- Housing: animals were housed one group per plastic shoebox cage with appropriate bedding
- Diet (e.g. ad libitum): PMI® Nutrition International, LLC Certified Rodent LabDiet® 5002
- Water (e.g. ad libitum): Water samples are analyzed for total bacterial counts, and the presence of coliforms, lead, and other contaminants
- Acclimation period: quarantined for a minimum of 6 days
- Indication of any skin lesions: free from any ear abnormalities (e.g., torn, scratched)

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-26ºC
- Humidity (%): 30-70%
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): approximate 12-hour light/dark cycle

Study design: in vivo (LLNA)

Vehicle:
dimethyl sulphoxide
Concentration:
5, 25, 50, 75%
No. of animals per dose:
5
Details on study design:
The objective of this study was to evaluate the potential of the test substance to produce a dermal sensitization response in mice using the local lymph node assay (LLNA). Five groups of 5 female CBA/JHsd mice were dosed for 3 consecutive days with 0% (vehicle control), 5%, 25%, 50%, or 75% of the test substance on both ears. Dimethylsulfoxide (DMSO) was used as the diluting vehicle. One group of 5 female mice was dosed for 3 consecutive days with 25% hexylcinnamaldehyde (HCA) in DMSO as a positive control. On test day 5 of the assay, mice received ³H-thymidine by tail vein injection and were sacrificed approximately 5 hours later. The cell proliferation in the draining auricular lymph nodes of the ears from the test substance groups was then evaluated and compared to the vehicle control group.
Positive control substance(s):
hexyl cinnamic aldehyde (CAS No 101-86-0)
Statistics:
Significance was judged at p < 0.05 except for dpm data that were judged at p < 0.01. Lymph node dpm data were transformed to Log to obtain normality or homogenous variances.

Results and discussion

In vivo (LLNA)

Results
Key result
Parameter:
SI
Value:
< 3

Any other information on results incl. tables

Table 1                     Stimulation Index Data

Group

Material tested

# of animals

Mean (dpm)

Standard deviation (dpm)

Stimulation Index

 

1

Vehicle Control

5

793.90

223.95

----

2

5%

5

618.10

148.39

0.78

3

25%

 4*

546.25

325.15

0.69

4

50%

5

453.70

94.23

0.57

5

75%

5

391.50

198.62

0.49

6

Positive Control

5

3552.70

733.45

4.47

 

* One mouse was not injected with the appropriate amount of radioactive material and the lymph nodes for this mouse were not analyzed

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The test substance is not a dermal sensitizer in mice
Executive summary:

The objective of this study was to evaluate the potential of the test substance to produce a dermal sensitization response in mice using the local lymph node assay (LLNA). Five groups of 5 female CBA/JHsd mice were dosed for 3 consecutive days with 0% (vehicle control), 5%, 25%, 50%, or 75% of the test substance on both ears. Dimethylsulfoxide (DMSO) was used as the diluting vehicle. One group of 5 female mice was dosed for 3 consecutive days with 25% hexylcinnamaldehyde (HCA) in DMSO as a positive control. On test day 5 of the assay, mice received ³H-thymidine by tail vein injection and were sacrificed approximately 5 hours later. The cell proliferation in the draining auricular lymph nodes of the ears from the test substance groups was then evaluated and compared to the vehicle control group (OECD Guideline 429)

 

No statistically significant differences in mean body weights and body weight gains compared to the vehicle control group were observed at any test concentration. No clinical signs of toxicity were observed in the study.

 

No statistically significant increases in cell proliferation measurements compared to the vehicle control group were observed at any test concentration. Stimulation indices (SIs) of less than 3.0 were observed at all test concentrations of the test substance. Therefore, the EC3 value (the estimated concentration required to induce a threshold positive response, i.e., SI = 3) for the test substance under the conditions of this study was not calculable. A 25% concentration of the positive control, HCA, produced a dermal sensitization response in mice. Therefore, the LLNA test system was valid for this study with the test substance. Under the conditions of this study, the test substance did not produce a dermal sensitization response in mice.

 

Based on these data, the test substance is not a dermal sensitizer in mice.