P-1057

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:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Details on test material:

- Physical state: solid
- Analytical purity: 96%
- Lot/batch No.: PQR0501558 (dried)
- Storage condition of test material: At room temperature, protected from light

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Netherlands, B.V. Postbus 6174, NL - 5960 AD Horst / The Netherlands
- Age at study initiation: 7 - 12 weeks (beginning of acclimatisation)
- Weight at study initiation: 20.1 ± 1.2 g (mean ± SD)
- Housing: Single; Makrolon Type I, with wire mesh top
- Diet (e.g. ad libitum): pelleted standard diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: Under test conditions after health examination. Only animals without any visible signs of illness were used
for the study.
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3ºC
- Humidity (%): 30 – 70 %
- Photoperiod (hrs dark / hrs light): artificial light 6.00 a.m. - 6.00 p.m.

Study design: in vivo (LLNA)

Vehicle:

dimethyl sulphoxide

Concentration:

2.5, 5, and 10 % (w/v)

No. of animals per dose:

4 females (nulliparous and non-pregnant) per group

Details on study design:

RANGE FINDING TESTS:
In a pre-test in two mice, test item concentrations of 1.25, 2.5, 5, and 10 % were tested on one ear each. No irritation effects
were observed at these
concentrations after a single application.
MAIN STUDY
- Criteria used to consider a positive response:
A test item is regarded as a sensitiser in the LLNA if the following criteria are fulfilled:
- First, that exposure to at least one concentration of the test item resulted in an incorporation of 3HTdR at least 3-fold or greater
than that recorded in control mice, as indicated by the stimulation index.
- Second, that the data are compatible with a conventional dose response, although allowance must be made (especially at high
topical concentrations) for either local toxicity or immunological suppression.
The decision to select a STIMULATION INDEX (S.I.) of 3 as an arbitrary indication of sensitizing activity was made on the basis
of investigations performed with a wide range of chemicals.
TREATMENT PREPARATION AND ADMINISTRATION:
Each test group of mice was treated by topical (epidermal) application to the dorsal surface of each ear lobe (left and right) with
different test item concentrations of 2.5, 5, and 10 % (w/v) in dimethylsulfoxide. The application volume, 25 μl, was spread over
the entire dorsal surface (ø 8 mm) of each ear lobe once daily for three consecutive days. A further group of mice was treated
with an equivalent volume of the relevant vehicle alone (control animals).
Five days after the first topical application, all mice were administered with 250 μl of 80.4 μCi/ml 3HTdR (corresponds to 20.1
μCi 3HTdR per mouse) by intravenous injection via a tail vein.

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.
- Mortality / Viability: once daily (week day) from experimental start to necropsy.
- Body weights: prior to the first application and prior to treatment with 3HTdR.
- Clinical signs (local / systemic): once daily (week day). Especially the treatment
sites were observed carefully.

Results and discussion

Positive control results:

Group 1: concentration 5%: Stimulation index: 2.04
Group 2: concentration 10%: Stimulation index: 6.31
Group 3: concentration 25%: Stimulation index: 12.45 EC3: 6.1% (w/v)

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

2.55

Test group / Remarks:

2.5%

Results 2

Key result

Parameter:

SI

Value:

1.63

Test group / Remarks:

5%

Results 3

Key result

Parameter:

SI

Value:

2.22

Test group / Remarks:

10 %

Results 4

Key result

Parameter:

EC3

Remarks on result:

not determinable

Remarks:

Could not be calculated since none of the tested concentrations induced and S.I. greter than 3

Any other information on results incl. tables

No deaths occurred during the study period. No symptoms of local toxicity at the ears of the animals and no systemic findings wereobserved during the study period. 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.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item was not a skin sensitiser in this assay.

Executive summary:

In the study the test item dissolved in dimethylsulfoxide was assessed for its possible contact allergenic potential. For this purpose a local lymph node assay was performed using test item concentrations of 2.5, 5, and 10 %. The animals did not show any clinical signs during the course of the study and no cases of mortality were observed. In this study Stimulation Indices (S.I.) of 2.55, 1.63, and 2.22 were determined with the test item at concentrations of 2.5, 5, and 10 % in dimethylsulfoxide, respectively. The test item was not a skin sensitiser in this assay.