Docosyl methacrylate

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:

2018

Report date:

2018

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

Reference substance name:

Docosyl methacrylate

EC Number:

240-714-1

EC Name:

Docosyl methacrylate

Cas Number:

16669-27-5

Molecular formula:

C26H50O2

IUPAC Name:

docosyl methacrylate

Test material form:

solid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Envigo RMS GmbH, C/O Postfach 553 NL-5800 AN Venray
- Age at study initiation: 9 weeks (pretest) / 8 weeks (main test)
- Weight at study initiation: 20.3 g - 21.7 g (prestest) / 18.1 g - 21.4 g (main test)
- Housing: single
- Diet (e.g. ad libitum):Kliba mouse/rat maintenance diet "GLP" supplied by Provimi Kliba SA, Kaiseraugst, Basel, Switzerland, ad libitum.
- Water (e.g. ad libitum): drinkin water ad libitum
- Acclimation period: 5 days before the first application

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24°C
- Humidity (%): 45 - 65%.
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

methyl ethyl ketone

Concentration:

2.5, 10 and 40 % (w/w)

No. of animals per dose:

5

Details on study design:

The test material is solid wax at room temperature. It had to be heated up to ca. 50 °C to get dissolved in the solvent MEK.

Each test group of mice was treated by (epicutaneous) topicla application to the dorsum fo both ears with test item concentrations of 2.5, 10 and 40% in MEK. The application volume 25 µL per ear, was spread over the dorsal surface of both ears once daily for three consecutive days. Treatment of control group 1 is analogous to that of the test groups, but only with the vehicle and without test substance.
On study day five (about 66 to 72 hours after the last application of test substance to the ears), 20 μCi 3H-thymidine1 in 250 μL sterile saline will be injected intravenously (i.v.) into a tail vein of the mice.
lmmediately after sacrifice, a circular piece of tissue (diameter 0.8 cm) will be punched out of the apical part of each ear of all animals. The weight of the pooled punches will be determined for each animal using an analytical balance. These measurements serve for detecting a potential inflammatory ear swelling.

Positive control substance(s):

other: A positive control with a substance that has been proven to cause skin sensitization in the animal strain used will not be included in this study. A separate study with a positive control is carried out in the laboratory twice a year.

Statistics:

Gell count, 3H-thymidine incorporation, lymph node weight and ear weight, WILCOXON - Test

Results and discussion

In vivo (LLNA)

Results

Results 1

Parameter:

EC3

Remarks:

%

Value:

9.3

Remarks on result:

other: thymidine incorporation

Results 2

Parameter:

other: EC1.5

Remarks:

%

Value:

19.4

Remarks on result:

other: cell-count stimulation index

Any other information on results incl. tables

Test item concentration	Group Calculation
	Mean DPM per animal (2 lymph nodes)	SD	S.I.
Vehicle Control Group (MEK)	180.9	56.0	1.00
2.5% Docosyl methacrylate	292.5	162.7	1.62
10 %Docosyl methacrylate	568.2	312.8	3.14
40% Docosyl methacrylate	624.2	223.2	3.45

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

The test item Docosyl methacrylate was a skin sensitiser under the test conditions of this study.