[No public or meaningful name is available]

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-10-22 to 2007-11-15

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:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

reported April 29, 1993

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted: 24th April 2002

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Version / remarks:

March 2003

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:

-

EC Number:

477-470-2

EC Name:

-

Molecular formula:

UVCB substance

IUPAC Name:

Reaction product of tetraethylsilicate, ethylpolysilicate, dioctyltinoxide, methanol and benzoic acid

Test material form:

liquid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA/Ca

Remarks:

CBA/Ca01aHSD

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelman GmbH, D-33178 Borchen
- Females nulliparous and non-pregnant: not specified
- Microbiological status of animals, when known: SPF
- Age at study initiation: 8 - 12 weeks old
- Weight at study initiation: 18 - 22 g
- Housing: Macrolon cages on Altromin saw fiber bedding
- Diet (ad libitum): Altromin 1324 maintanenance diet for rats and mice, specific pathogen-free
- Water (ad libitum): tap water
- Acclimation period: at least 5 days
- Indication of any skin lesions: not specified

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3
- Humidity (%): 55 +/- 10
- Air changes (per hr): at least 10
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

25%, 50%, 100%

No. of animals per dose:

5 animals per dose

Details on study design:

PRE-SCREEN TESTS

with 50% and 100%

- Compound solubility: yes
- Irritation: none at 50%, hair loss at 100%
- Systemic toxicity: none at 50%,
- Ear thickness measurements: below 30%
- Erythema scores: none


MAIN STUDY

ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response: stimulation index equal to or greater than 3.0.

TREATMENT PREPARATION AND ADMINISTRATION:
Topical application of 25 µL of the test item was performed once daily over three consecutive days.

Statistics:

EC3 value calculation was performed according to OECD 429.

Results and discussion

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

EC3

Value:

> 76

Test group / Remarks:

test item

Results 2

Parameter:

SI

Value:

2.1

Test group / Remarks:

25%

Results 3

Parameter:

SI

Value:

1.7

Test group / Remarks:

50%

Results 4

Parameter:

SI

Value:

4.2

Test group / Remarks:

100%

Cellular proliferation data / Observations:

CLINICAL OBSERVATIONS:
Please refer to "signs of toxicity". No other clinical signs were recorded in any of the animals.

BODY WEIGHTS
Weight development of all animals was within the expected range, which includes a weight loss of up to 2 g throughout the study. As the weight loss was observed in dosed animals only, test item relation cannot be excluded.

SIGNS OF TOXICITY
Animals treated with 100% of the test item showed hair los and clotted hair.

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

The test item was concluded to be a skin sensitizer. A stimulation index (SI) of > 3 was recorded for a test item concentration of 100%, the EC3 value (derived by linear interpolation) was calculated to be at least 76%.

Executive summary:

The test item was assayed for skin sensitizing properties in the Local Lymph Node Assay (LLNA) according to OECD 429. Based on the results of a preliminary study, test item concentrations of 25%, 50% and 100% were used. The vehicle was Acetone/Olive Oil (AOO).

Each mouse was treated by topical application of the prepared test item to the entire dorsal surface of each ear daily over three consecutive days.

Five days after the first topical application, all mice were injected intravenously with [3]H-methyl thymidine. Approximately 5 hours after the injection, all mice were sacrificied. The draining "auricular lymphnodes nodes" were excised.

A single cell suspension of the lymph nodes for each animal was prepared. The [3]H-methyl thymidine-incorporation was measured in a beta-counter and expressed as the number of disintgrations per minute (DPM). Determination of radioactivity was performed individually for each animal.

The proliferative response of lymph nodes was calculated as the ratio of [3]H-methyl thymidine- incorporation into lymph node cells of test group animals. A stimulation index (SI) of the test item/ negative control was calculated for each concentrtation.

Weight development of all animals was within the expected range, which includes a weight loss of up to 2 g throughout the study.

All animals tested with the 100% concentration showed hair loss and clotted hair. No other visible clinical symptoms were recorded at the daily clinical observation in any the animals.

SI-values of 2.1, 1.7 and 4.2 were calculated for 25%, 50% and 100% of the test item. The EC3 value (derived by linear interpolation) was calculated to be at least 76%. 

The test item was concluded to be a skin sensitizer.