1-vinylimidazole

Skin sensitisation

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:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

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:

1-vinylimidazole

EC Number:

214-012-0

EC Name:

1-vinylimidazole

Cas Number:

1072-63-5

Molecular formula:

C5H6N2

IUPAC Name:

1-ethenyl-1H-imidazole

Details on test material:

- Identity: 1-Vinylimidazol
- Appearance: Yellowish, clear liquid
- Batch No.: 87876088Q0
- BASF Substance No.: 00/0335-3
- Purity: 99.8 corr. area-%. Additionally the test item was characterized by IR-, 1H-NMR- and 13C-NMR-spectroscopy and showed the expected signals
- Homogeneity: The test substance appeared to be homogeneous
- Stability in Solvent: Not indicated by the sponsor
- Storage: At room temperature
- Expiration Date: June 21, 2012

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River UK, Manston Road, Margate, Kent CT9 4LT, United Kingdom
- Age at study initiation: pre-test 1 and 3: 9-10 weeks, pre-test 2 and main study: 8-9 weeks
- Weight at study initiation: 17.1-20.3 g
- Housing: Animals were group housed in Makrolon Type III cages, with wire mesh top (EHRET GmbH, 79302 Emmendingen, Germany) and granulated soft wood bedding (Rettenmaier & Söhne GmbH + Co. KG, 73494 Rosenberg, Germany).
- Diet: Pelleted standard diet, ad libitum (Harlan Laboratories B.V., 5960 AD Horst, Netherlands)
- Water: Tap water, ad libitum (Gemeindewerke, 64380 Rossdorf, Germany)
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2
- Humidity (%): 44 - 109
- Photoperiod (hrs dark / hrs light): 12 / 12

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

1, 2.5, and 5 % (w/w)

No. of animals per dose:

5

Details on study design:

Three groups each of five female mice were treated with different concentrations of the test item by topical application at the dorsum of each ear once daily each on three consecutive days. A control group of five 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, pooled per animal and immediately weighed using an analytical balance. Both ears were punched at the apical area and the punches were immediately weighed pooled per animal. Afterwards, single cell suspensions of lymph node cells were prepared from lymph nodes pooled per animal. An aliquot of each cell suspension was used for determination of lymph node cell count. The suspensions were washed and incubated with trichloroacetic acid overnight. The proliferative capacity of pooled lymph node cells was 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:

The mean values and standard deviations were calculated in the body weight tables and for the DPM values (group mean DPM ± standard deviation) as well as for the ear weights, lymph node weights and lymph node cell counts.
A statistical analysis was conducted on the DPM values, the ear weights, the lymph node weights and the lymph node cell count to assess whether the difference was statistically significant between test item groups and negative control group.
For all statistical calculations SigmaStat for Windows (Version 2.0) was used. A One-Way-Analysis-of-Variance was used as statistical method. In case of significant results of the One-Way-ANOVA, multiple comparisons were performed with the Dunnett test. Statistical significance was set at the five per cent level (p < 0.05).
However, both biological and statistical significance were considered together.

Results and discussion

Positive control results:

Mean DPM per animal and S.I. (a-hexyl cinnamalderhyde in AOO)
0 % (w/v): DPM = 460, S.I. = 1.00
5 % (w/v): DPM = 621.1, S.I. = 1.35
10 % (w/v): DPM = 1004.3, S.I. = 2.18
25 % (w/v): DPM = 3720.5. S.I. = 8.08

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Value:

1

Test group / Remarks:

vehicle (AOO 4+1 v/v)

Results 2

Parameter:

SI

Value:

1.02

Test group / Remarks:

1% test substance

Results 3

Parameter:

SI

Value:

0.81

Test group / Remarks:

2.5% test substance

Results 4

Parameter:

SI

Value:

1.11

Test group / Remarks:

5% test substance

Cellular proliferation data / Observations:

- Viability / Mortality: No deaths occurred during the study period.
- Clinical Signs: No systemic findings were observed during the study period. On day 3 only, a slight erythema of the ear skin was observed in the high dose group. In the other groups, no signs of local skin irritation were observed.
- Body Weights: 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.
- Lymph Node Weights and Cell Counts: The measured lymph node weights and –cell counts of all animals treated were recorded after sacrifice. No statistically significant or biologically relevant increase in lymph node weights or lymph node cell count was not observed in any of the test item treated groups in comparison to the vehicle control group.
- Ear Weights: The measured ear weights of all animals treated were recorded after sacrifice. A statistically significant or biologically relevant increase in ear weights was not observed in any treated group in comparison to the vehicle control group.

Any other information on results incl. tables

DPM per group [mean +/- SD]:

- vehicle (AOO 4 +1 v/v): 866.4 +/- 242.4

- 1% test substance: 881.0 +/- 252.8

- 2.5% test substance: 704.0 +/- 338.3

- 5% test substance: 959.6 +/- 187.8

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met