2-hydroxy-3-(prop-2-enoyloxy)propyl 2-methyl-2-propylhexanoate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From June 17, 2015 to July 21, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

but did not affect the validity of the study

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

but did not affect the validity of the study

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Justification for non-LLNA method:

-

Test material

Test material information

Constituent 1

Reference substance name:

Neodecanoic acid, 1-ester with 1,2,3-propanetriol mono-2-propenoate

Molecular formula:

C16H28O5

IUPAC Name:

Neodecanoic acid, 1-ester with 1,2,3-propanetriol mono-2-propenoate

Constituent 2

Reference substance name:

Neo undecanoic acid, 1-ester with 1,2,3-propanetriol mono-2-propenoate

Molecular formula:

C17H30O5

IUPAC Name:

Neo undecanoic acid, 1-ester with 1,2,3-propanetriol mono-2-propenoate

Constituent 3

Reference substance name:

glycerol 1,3-dineodecanoate

Molecular formula:

C23H44O5

IUPAC Name:

glycerol 1,3-dineodecanoate

Constituent 4

Reference substance name:

Sum of other constituents, each of them at <1%

Molecular formula:

Not available

IUPAC Name:

Sum of other constituents, each of them at <1%

Test material form:

liquid

Specific details on test material used for the study:

Batch no.: JBGJ0045R
Purity: 100% (UVCB)
Appearance: clear yellowish liquid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA/Ca

Remarks:

CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

Source: Harlan Laboratories B.V. Postbus 6174 5960 AD Horst / The Netherlands
Acclimatization: at least 5 days
Body weight: ca. 20g
Temperature: ca. 22±2°C, relative humidity : ca. 45-65% and light regimen: 12-hour light /12-hour dark cycle
Diet: 2018C Teklad Global 18% protein rodent diet, ad libitum
Water: tap water, ad libitum

Study design: in vivo (LLNA)

Vehicle:

acetone/olive oil (4:1 v/v)

Concentration:

0, 0.5, 1 and 2.5% (w/w)
(Pre-tests: 50, 25, 10 and 5%)

No. of animals per dose:

4

Details on study design:

Three groups each of four female mice were treated with different concentrations (25 µL of 0, 0.5, 1, and 2.5% (w/w) in acetone/olive oil (4+1, v/v)) of the test substance by topical application at the dorsum of each ear once daily each on three consecutive days. The highest concentration tested was the highest concentration that could be achieved whilst avoiding systemic toxicity and excessive local skin irritation as confirmed by three pre-experiments. A control group of four mice was treated with the vehicle only. Five days after the first topical application, the mice were intravenously injected into a tail vein with radio-labelled thymidine (3H-methyl thymidine; 3HTdR). Approximately five hours after intravenous injection, the mice were sacrificed and the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes, which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was then determined by the incorporation of 3H-methyl thymidine measured in a β-scintillation counter.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

Mean values and standard deviations

Results and discussion

Positive control results:

alpha- hexylcinnamaldehyde 25% (w/w) in acetone/olive oil (4+1, v/v): S.I. value of 9.5 and was therefore regarded as a sensitiser in the LLNA test, since the exposure to one or more test concentrations resulted in a 3-fold or greater increase in incorporation of 3HTdR compared with concurrent controls.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

1

Test group / Remarks:

0.0% (w/w) in acetone/olive oil (4+1, v/v)

Remarks on result:

other: negative control

Results 2

Key result

Parameter:

SI

Value:

0.84

Test group / Remarks:

0.5% (w/w) in acetone/olive oil (4+1, v/v)

Remarks on result:

other: at 0.5% conc; not a skin sensitiser

Results 3

Key result

Parameter:

SI

Value:

0.92

Test group / Remarks:

1.0% (w/w) in acetone/olive oil (4+1, v/v)

Remarks on result:

other: at 1% conc; not a skin sensitiser

Results 4

Key result

Parameter:

SI

Value:

1.22

Test group / Remarks:

2.5% (w/w) in acetone/olive oil (4+1, v/v)

Remarks on result:

other: at 2.5% conc; not a skin sensitiser

Cellular proliferation data / Observations:

The animals did not show any signs of systemic toxicity during the course of the study and no cases of mortality were observed. The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age. A very slight erythema (score: 1) was observed in the animals of the high dose group on test day 3. In this study, Stimulation Indices (S.I.) of 0.84, 0.92, and 1.22 were determined with the test substance at concentrations of 0.5, 1, and 2.5% (w/w) in acetone/olive oil (4+1, v/v), respectively. The test substance was not a skin sensitiser under the test conditions of this study.
(The estimated concentration of test substance required to produce a S.I. of 3 is referred to as the EC3 value. In this study, the EC3 value could not be calculated, since none of the tested concentrations induced a S.I. greater than the threshold value of 3.)

Applicant's summary and conclusion

Interpretation of results:

other: CLP criteria not met

Remarks:

does not need to be classified

Conclusions:

Under the study conditions, the test substance was not a skin sensitiser (LLNA).

Executive summary:

A study was conducted to determine the skin sensitisation potential of the test substance according to OECD Guideline 429 and EU Method B.42, in compliance with GLP. Groups of 4 female CBA/Ca mice each were treated with 0, 0.5, 1, and 2.5% (w/w) preparations of the test substance in acetone/olive oil (4+1, v/v)) or with the vehicle alone. The highest concentration tested was the highest concentration that could be achieved whilst avoiding systemic toxicity and excessive local skin irritation as confirmed by three pre-experiments. The study used 3 test groups and 1 control groups (vehicle). 25 µL of the respective test substance preparation or of the vehicle were applied to the dorsum of both ears of each animal once daily for three consecutive days. Five days after the first topical application, the mice were intravenously injected into a tail vein with radio-labelled thymidine (3H-methyl thymidine; 3HTdR). Approximately five hours after intravenous injection, the mice were sacrificed and the draining auricular lymph nodes excised and pooled per group. Single cell suspensions of lymph node cells were prepared from pooled lymph nodes, which were subsequently washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was then determined by the incorporation of 3H-methyl thymidine measured in a β-scintillation counter. Mortality / viability was reported at least once daily from experimental start to necropsy. Body weights was measured prior to the first application and prior to treatment with 3HTdR. Clinical signs (local / systemic) were recorded at least once daily. The animals did not show any signs of systemic toxicity during the course of the study and no cases of mortality were observed. The body weight of the animals, recorded prior to the first application and prior to treatment with 3HTdR, was within the range commonly recorded for animals of this strain and age. A very slight erythema (score: 1) was observed in the animals of the high dose group on test day 3. In this study, Stimulation Indices (S.I.) of 1.00, 0.84, 0.92, and 1.22 were determined with the test substance at concentrations of 0, 0.5, 1, and 2.5% (w/w) in acetone/olive oil (4+1, v/v), respectively. The EC3 value could not be calculated, since none of the tested concentrations induced a S.I. greater than the threshold value of 3. Under the study conditions, the test substance was not a skin sensitiser (LLNA) (Roth, 2015).