2-ethylhexyl 10-ethyl-4-[[2-[(2-ethylhexyl)oxy]-2-oxoethyl]thio]-4-methyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

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:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

, none that affected the integrity of the study

GLP compliance:

yes

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexyl 10-ethyl-4-[[2-[(2-ethylhexyl)oxy]-2-oxoethyl]thio]-4-methyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

EC Number:

260-828-5

EC Name:

2-ethylhexyl 10-ethyl-4-[[2-[(2-ethylhexyl)oxy]-2-oxoethyl]thio]-4-methyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

Cas Number:

57583-34-3

Molecular formula:

C31H60O6S3Sn

IUPAC Name:

2-ethylhexyl 10-ethyl-4-({2-[(2-ethylhexyl)oxy]-2-oxoethyl}sulfanyl)-4-methyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecan-1-oate

Test material form:

liquid

Details on test material:

- Analytical purity: 88.7 %
- Purity test date: 2009-08-21
- Lot/batch No.: GKN2009-65
- Expiration date of the lot/batch: 2011-12-01
- Stability under test conditions: stable
- Storage condition of test material: room temperature

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/Ca

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan UK
- Age at study initiation: 11 to 12 weeks
- Weight at study initiation: 20.7 to 24.5 grams
- Housing: housed individually in solid floor standard polysulfone cages (Size: Approximately L 360 x B 205 x H 140 mm), with stainless steel top grill
- Diet (e.g. ad libitum): Ssniff mice pellet food, ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 5 days before the start of treatment


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 23 deg C
- Humidity (%): 57 to 66 %
- Air changes (per hr): 14.2 air changes/hr
- Photoperiod (hrs dark / hrs light): 12 hrs light/ 12 hrs dark


IN-LIFE DATES: From: 2009-08-03 To: 2009-08-18

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

5, 25, 50, 75 % in vehicle and 100 % of the test substance

No. of animals per dose:

6

Details on study design:

RANGE FINDING TESTS:
- Compound solubility: The test item was miscible at all the tested concentrations in Acetone:olive oil
- Irritation: erythema was observed at 75 and 100 % concentrations
- Lymph node proliferation response: screen looked at irritation only

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: randomly distributed to different groups by body weight stratification method.
- Criteria used to consider a positive response: Any test material that produces a SI , 3 in the LLNA is normally considered "positive" for dermal sensitisation potential

TREATMENT PREPARATION AND ADMINISTRATION:
The test substance was combined with Acetone Olive oil to obtain concentrations of 5, 25 and 50 % v/v. Test item solution was prepared daily just prior to dosing.
The application of the test item (25 µL/ear) was made on the dorsum of both ears in a manner to prevent test item loss. Six female
mice/group received vehicle (Acetone : Olive oil) or positive control (30 % α-hexylcinnamaldehyde) or 5, 25 and 50 % test substance once daily for three consecutive days. Ears were inspected prior to application on test item solution, and erythema was evaluated on days 2,3 and 6. All mice were weighed on days 1 and 6.

Positive control substance(s):

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

Statistics:

Means and SD were generated for body weight data (absolute and gain) and LLNA response (dpm and SI values). The body weight and dpm data
were analysed by one-way analysis of variance. When the differences are indicated by the ANOVA, a comparison of treated vs. control groups was done using a Dunnett's t-test (Ps0.05). Statistically significant differences (P≤ 0.05).

Results and discussion

Positive control results:

30 % HCA in Acetone: olive oil elicited a stimulation index (SI) of 8.48, in comparison with the vehicle-treated mice

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

2.13

Test group / Remarks:

5 % v/v test substance

Results 2

Key result

Parameter:

SI

Value:

7.25

Test group / Remarks:

25 % v/v test substance

Results 3

Key result

Parameter:

SI

Value:

9.05

Test group / Remarks:

50 % v/v test substance

Results 4

Key result

Parameter:

EC3

Value:

8.4

Cellular proliferation data / Observations:

DPM/Mouse:
- Vehicle (AOO): 1000.50; 378.07
- 30 % HCA in AOO: 8482.50; 2857.66
- 5 % test substance in AOO: 2131.33; 568.45
- 25 % test substance in AOO: 7251.83; 1066.03
- 50 % test substance in AOO: 9054.67; 2509.62

Any other information on results incl. tables

The analysed radioactivity of 3H-TdR working solution was 83.72 uCi/mL against the nominal concentration of 80 uCi/mL.

Applicant's summary and conclusion

Interpretation of results:

other: Classified as a sensitiser as Category 1B in accordance with EU criteria

Conclusions:

Topical application with 5, 25 and 50 % v/v test substance elicited a stimulation index (SI) of 2.13, 7.25 and 9.05, respectively. The calculated EC3 value was 8.40 %

Executive summary:

The Local Lymph Node Assay (LLNA) was conducted to evaluate the potential of the test substance to cause contact sensitization by measuring lymphocyte proliferative response from auricular lymph nodes following topical application of the test item to the female CBA/Ca mouse ear.

Screening Study: Three daily topical application of 5, 25, 50 and 75 % v/v in Acetone Olive oil and 100 % of the test substance were given to one animal at each dose level. Erythema was observed at 75 and 100 % concentration. The mice exposed to 50, 75 and 100 % concentration lost body weights. Results from this study were used to determine the dosing concentration in the LLNA study.

LLNA study: Six female CBA/Ca mice group received vehicle (Acetone Olive oil [AOO]) or 30 % α-hexylcinnarnaldehyde (HCA: positive control in AOO) or 5, 25 and 50 % of the test substance on days 1 to 3. On day 6, uptake of 3H-methyl thymidine into the auricular lymph nodes draining the site of test item application was measured five hours post administration. Proper conduct of the LLNA was confirmed via a positive response using 30 % α-hexylcinnamaldehyde, contact sensitiser, which elicited proliferation with a Stimulation Index (SI) value of 8.48, in comparison to vehicle-treated mice. The test substance did not elicit erythema. The test substance at the dose concentration of 50 % v/v decreased the body weight gain. The SI values for 5, 25 and 50 % of test substance were 2.13, 7.25 and 9.05, respectively. The EC3 value was 8.40 %.