3-methyl-5-phenylpent-2-enenitrile

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-03-02 to 2007-03-06

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2002

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

3-methyl-5-phenylpent-2-enenitrile

EC Number:

299-682-2

EC Name:

3-methyl-5-phenylpent-2-enenitrile

Cas Number:

93893-89-1

Molecular formula:

C12 H13 N

IUPAC Name:

(2E)-3-methyl-5-phenylpent-2-enenitrile

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 15-23 g
- Housing: individually
- Diet: certified rat and mouse diet, ad libitum
- Water: tap water ad libitum
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 30-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

1, 0.5, 0.25 %

No. of animals per dose:

4

Details on study design:

RANGE FINDING TESTS:
- Irritation: Seven mice were treated daily by application of 25 µL of the undiluted test material and concentrations of 50, 25, 10, 5, 2.5 and 1 %. Severe signs of systemic toxicity were observed in all dose groups except the 1 % dose group. The dose level selected for the main test was therefore 1 %.

MAIN STUDY

TREATMENT PREPARATION AND ADMINISTRATION:
Groups of four mice per concentration were treated by daily application of 25 µL to the dorsal surface of each ear for three consecutive days. Administration was carried out using an automatic micropipette and spread over the dorsal surface of the ear using the tip of the pipette.

Positive control substance(s):

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

Statistics:

The proliferation response of lymph node cells was expressed as the number of radioactive disintegrations per minute per lymph node (disintegrations per minute/node) and as the ratio of 3HTdR incorporation into lymph node cells of test nodes relative to that recorded for the control nodes (Stimulation Index).

The EC3 value is the concentration of test material expected to cause a 3 fold increase in HTdR incorporation.
The equation used for the calculation of EC3 is:
EC3 = c + [(3-d/b-d) x (a-c)]
a = lowest concentration giving stimulation index >3
b = actual stimulation index caused by a
c = highest concentration failing to produce a stimulation index of 3
d = actual stimulation index caused by c

Results and discussion

Positive control results:

The stimulation index (expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group) of a 5 % (v/v) concentration in acetone/ olive oil 4:1 was 2.5, the SI of a 10 % concentration was 4.03 and the SI of a 25 % concentration was 9.13. Therefore, the positive control substance was considerd to be a sensitiser.

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

EC3

Value:

0.77

Test group / Remarks:

in %

Results 2

Parameter:

SI

Value:

3.75

Test group / Remarks:

Test substance concentration 1 %

Results 3

Parameter:

SI

Value:

2.16

Test group / Remarks:

Test substance concentration 0.5 %

Results 4

Parameter:

SI

Value:

2.11

Test group / Remarks:

Test substance concentration 0.25 %

Any other information on results incl. tables

Table 1: Disintegrations per Minute, Disintegrations per Minute/Node and Stimulation Index

Concentration (% v/v) in acetone/olive oil 4:1	DPM	DPM/Node	Stimulation Index	Result
Vehicle	7740.67	967.58	NA	NA
0.25	16328.71	2041.09	2.11	Negative
0.5	16749.20	2093.65	2.16	Negative
1	29046.08	3630.76	3.75	Positive

An EC3 value of 0.77% was calculated.

Applicant's summary and conclusion

Interpretation of results:

Category 1A (indication of significant skin sensitising potential) based on GHS criteria

Conclusions:

The test substance was found to be skin-sensitising.

Executive summary:

A study was performed to assess the skin sensitization potential of the test material in the CBA/Ca strain mouse following topical application to the dorsal surface of the ear. The study was performed according to OECD Guideline 429 and GLP. Following a preliminary screening test, three groups, each of four animals, were treated with 50 µL (25 (µL per ear) of the test material as a solution in acetone/olive oil 4:1 at concentrations of 1 %, 0.5 % or 0.25 % v/v. A further group of four animals was treated with acetone/olive oil 4:1 alone. The stimulation indices of the concentrations 0.25, 0.5 and 1 % were 2.11, 2.16 and 3.75, respectively. An EC3 value of 0.77 % was calculated. Therefore, the test result of the substance at a concentration of 1 % was considered positive and the test substance was found to be a skin sensitiser (Cat. 1A).