Registration Dossier

Administrative data

Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
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:
other: OECD guideline and EU method. GLP study.
Reference:
Composition 0
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymphnode assay (LLNA)
Test material information:
Composition 1
Species:
mouse
Strain:
other: CBA/Ca (sub-strain CBA/CaOlaHsd
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories UK Ltd., Oxon
- Age at study initiation: Approx. 8 - 12 weeks at start of treatment
- Weight at study initiation: 15 - 23g at start of treatment
- Housing: Housed in suspended polypropylene cages fitted with stainless steel mesh lids and furnished with softwood woodflakes (Datesand Ltd., Cheshire, UK). The animals will be individually housed during the study to avoid the transfer of test item between animals.
- Diet (e.g. ad libitum): Rodent 2014C Teklad Global Certified Diet, ad libitum.
- Water (e.g. ad libitum): Tap water, ad libitum.
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 30 to 70%
- Air changes (per hr): At least fifteen air changes per hour
- Photoperiod (hrs dark / hrs light): Twelve hours of continuous artificial light in each twenty-four hour period
Vehicle:
propylene glycol
Concentration:
5, 10 and 25%
No. of animals per dose:
Five animals per dose
Details on study design:
MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Criteria used to consider a positive response:
For each individual animal, the proliferative response of the lymph node cells will be expressed as the number of radioactive disintegrations per minute per animal (DPM/animal). The mean DPM/animal will be determined for each test group and also for the vehicle control group. The ratio of 3HTdR incorporation into the l ymph node cells of test nodes relative to that recorded for the control nodes (the Stimulation Index; SI) will be calculated for each test concentration by dividing the mean DPManimal of each test group by the DPM/animal of the vehicle control group.

The decision process with regard to identification of a positive response will include a SI of ≥ 3, together with consideration of dose-response, and where appropriate, statistical significance. Any test item failing to produce a SI of ≥ 3 at all test concentrations will not be regarded as a skin sensitiser.

When a positive response is obtained, it may be possible to calculate an EC3 value. The EC3 represents the concentration of test item expected to cause a 3-fold increase in 3HTdR incorporation (increase in draining lymph node cell proliferative activity) compared with the concurrent vehicle treated controls. It is therefore the effective concentration of test item required to produce a SI of 3.

TREATMENT PREPARATION AND ADMINISTRATION:
The mice will be treated by daily application of 25 µl of the appropriate concentration of the test item to the dorsal surface of each ear for three consecutive days (Days 1, 2, 3). The test item will be administered using an automatic micropipette. The test substance will be spread over the entire dorsal surface of the ear using the tip of the pipette.

A further group of five mice will receive the vehicle alone in the same manner.

3H-methyl thymidine Administration
Five days following the first topical application of the test item (Day 6) all mice will be injected via the tail vein with 250 µI of phosphate buffered saline (PBS) containing 3H-methyl thymidine (3HTdR:80 µCi/ml) giving a total of 20 µCi to each mouse. If intravenous injection of the required amount of3H-methyl thymidine is unsuccessful, then the mouse/mice will be removed from the group and the assay continued using the remaining mice. Rejection of the animal(s) will be
documented.
Positive control substance(s):
other: phenylacetaldehyde
Positive control results:
SI of 6.48 at a concentration of 2.5%.

Table 1: Summary of results

Concentration

mean dpm/animal

Test / Control Ratio

Result

Blank

1526.37

N/A

N/A

5%

7478.87

4.90

Positive

10%

6980.21

4.57

Positive

25%

9287.12

6.08

Positive

Interpretation of results:
sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Based on the results, the substance is classified as skin sensitiser.
Executive summary:

The study was performed to assess the skin sensitising potential of the test item in the mouse following topical application to the dorsal surface of the ear. The method was designed to be compatible with the following:

- OECD Guidelines for the Testing of Chemicals No. 429

- Method B42 of Commission Regulation (EC) No. 440/2008

Based on the results, the substance is classified as skin sensitiser. Based on the results, the substance is classified as skin sensitiser.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

Key study: OECD guideline 429 and EU method B.42. GLP study.

Based on the results, the substance is classified as a skin sensitiser.


Migrated from Short description of key information:
Key study: OECD guideline 429 and EU method B.42. GLP study.
Based on the results, the substance is classified as a skin sensitiser.

Justification for selection of skin sensitisation endpoint:
Only one study available

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the results, the substance is classified as a skin sensitiser.