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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:
19 Apr 2011 to 22 Jun 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
yes
Qualifier:
according to guideline
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
yes
Principles of method if other than guideline:
The deviations had no impact on the quality, integrity or validity of the study.
GLP compliance:
yes
Type of study:
mouse local lymph node assay (LLNA)

Test material

Constituent 1
Chemical structure
Reference substance name:
3,7-dimethyloctanal
EC Number:
227-810-9
EC Name:
3,7-dimethyloctanal
Cas Number:
5988-91-0
Molecular formula:
C10H20O
IUPAC Name:
3,7-dimethyloctanal
Specific details on test material used for the study:
TEST MATERIAL
Name ( stated on the report) : 992123 (Virisal)
Appearance: Clear colorless liquid
Batch: 1000346568

In vivo test system

Test animals

Species:
mouse
Strain:
CBA:J
Sex:
female
Details on test animals and environmental conditions:
- Age Range: 9-10 weeks at start of dosing; records of dates of birth for animals used in this study are retained in the Calvert archives.
- Body Weight Range: 18-26 grams at the outset (Day 1) of the study.
- Animal Source: Harlan
- Identification: Tail marked with an indelible marker
- Housing: Animals were group-housed 5 per cage upon receipt in compliance with National Research Council "Guide for the Care and Use of Laboratory Animals". Animals were also group-housed during the study (5 per cage). The room in which the animals were kept was documented in the study records. No other species were kept in the same room.
- Lighting: 12 hours light/12 hours dark
- Room Temperature: 24 to 27°C
- Relative Humidity: 26 to 69%
- Food: Animals had access to Harlan Teklad Certified Rodent Chow 2016C ad libitum.
- Water: Tap water was available ad libitum, via water bottles.
- Acclimation: Study animals were acclimated to their housing for seven days prior to their first day of dosing.

Study design: in vivo (LLNA)

Vehicle:
other: 3:1 Diethyl Phthalate :Ethanol (3:1 DEP:EtOH)
Concentration:
2.5%, 5%, 10%, 25% and 50%
No. of animals per dose:
5 animals per group dose
Details on study design:
- Route: Topically on the dorsal surface of both ears
- Frequency: Once daily for 3 consecutive days (Days 1-3). The timing of dose administration remained consistent(± 2 hours) during the dosing phase.
- Procedure: A volume of 25 μI/ear was applied using a micropipette.
Positive control substance(s):
other: HCA at 5%, 15% and 35%

Results and discussion

In vivo (LLNA)

Results
Key result
Parameter:
SI
Value:
< 3

Any other information on results incl. tables

There was no mortality and all animals appeared normal throughout the study.

No erythema or edema was noted in any of the mice in the vehicle group or in those dosed with the test article at 2.5%, 5%, 10%, 25% or 50% (v/v). The ears of the mice treated with the vehicle appeared wet on Days 3 through 6, while the ears of all the mice in all the test article treated groups appeared wet on Days 2 through 6. There were no other findings. Mean body weights at Day 1 and Day 6 and mean changes in body weights were evaluated. There were no statistically significant differenced in mean body weights on Days 1 and 6 or in the mean body weight changes between any of the groups. Therefore, administration of the test article or positive control did not appear to exert any overt toxicity.

At termination, the lymph nodes from the mice treated with test article at concentrations of 2.5%, 5%, 10% and 50% (v/v) were normal in size and appearance. The lymph nodes from one of the five test article treated mice at 25% and one of the vehicle treated mice were enlarged but otherwise normal in appearance. Exposure to 992123 (Virisal) at concentrations of 2.5%, 5%, 10%, 25% or 50% (v/v) resulted in stimulation indices of 0.9, 0.8, 0.8, 1.2, and 0.8, respectively. There were no statistically significant differences between any of the groups.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
A test material is considered to have skin sensitizing activity if, at one or more concentrations, it induces a 3-fold or greater increase in proliferative activity relative to the concurrent vehicle treated control. Thus, a stimulation index : 3.0 is regarded as a positive response. Therefore, based on the criteria of this study, treatment with 992123 (Virisal) at concentrations up to 50% did not resulted in a stimulation indices of 3.0 or greater and hence it is not considered to have skin sensitizing activity.
Executive summary:

The purpose of this study was to determine if the test article, Virisal would induce a hypersensitivity response in mice as measured by the proliferation of lymphocytes in the draining lymph nodes according to the OECD Guideline No. 429.

Groups of 5 CBA/J female mice were treated on the dorsal surface of both ears once per day for 3 days with 2.5%, 5%, 10%, 25% or 50% (v/v) of 992123 (Virisal), or with the vehicle (3:1 Diethyl Phthalate:Ethanol [3:1 DEP:EtOH]). On Day 6, the mice were injected, i.v., with 20 μCi of 3H-thymidinein sterile saline. Five hours later, the mice were euthanized and the draining auricular lymph nodes were removed. The lymph node cells from individual mice (un-pooled) were precipitated with 5% trichloroacetic acid (TCA) and the pellets counted in a r..-scintillation counter to determine incorporation of the 3H-thymidine.

There was no mortality and all animals appeared normal throughout the study.

No erythema or edema was noted in any of the mice in the vehicle group or in those dosed with the test article at 2.5%, 5%, 10%, 25% or 50% (v/v). The ears of the mice treated with the vehicle appeared wet on Days 3 through 6, while the ears of all the mice in all the test article treated groups appeared wet on Days 2 through 6. There were no other findings. Mean body weights at Day 1 and Day 6 and mean changes in body weights were evaluated. There were no statistically significant differenced in mean body weights on Days 1 and 6 or in the mean body weight changes between any of the groups. Therefore, administration of the test article or positive control did not appear to exert any overt toxicity.

At termination, the lymph nodes from the mice treated with test article at concentrations of 2.5%, 5%, 10% and 50% (v/v) were normal in size and appearance. The lymph nodes from one of the five test article treated mice at 25% and one of the vehicle treated mice were enlarged but otherwise normal in appearance. Exposure to 992123 (Virisal) at concentrations of 2.5%, 5%, 10%, 25% or 50% (v/v) resulted in stimulation indices of 0.9, 0.8, 0.8, 1.2, and 0.8, respectively. There were no statistically significant differences between any of the groups.

A test material is considered to have skin sensitizing activity if, at one or more concentrations, it induces a 3-fold or greater increase in proliferative activity relative to the concurrent vehicle treated control. Thus, a stimulation index : 3.0 is regarded as a positive response. Therefore, based on the criteria of this study, treatment with 992123 (Virisal) at concentrations up to 50% did not resulted in a stimulation indices of 3.0 or greater and hence it is not considered to have skin sensitizing activity.