1-methyltrimethylene dimethacrylate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 November 2013 - 19 November 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

individual approach (adopted 22 July 2010)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)

Version / remarks:

dated May 30, 2008

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:

Tetramethylene dimethacrylate

EC Number:

218-218-1

EC Name:

Tetramethylene dimethacrylate

Cas Number:

2082-81-7

Molecular formula:

C12H18O4

IUPAC Name:

butane-1,4-diyl bis(2-methylacrylate)

Test material form:

liquid

In vivo test system

Test animals

Species:

mouse

Strain:

other: Mice, CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- CBA/CaOlaHsd mice, nulliparous, non-pregnant
- Age at study initiation (pre-test and main study): 8 - 9 weeks (beginning of treatment)
- Weight at study initiation (main test): 17.8 g - 22.3 g
- Housing: single; Makrolon Type II (pre-test)/ III (main study, with wire mesh top
- Diet (e.g. ad libitum):2018C Teklad Global 18% protein rodent diet (certified), ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: at least 5 days prior to start of dosing
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C ± 2°C
- Humidity (%): 35-65 %
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 / 12

Study design: in vivo (LLNA)

Vehicle:

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

Concentration:

1 (Control ) 0
2 (Low Dose) 25% (w/v)
3 (Mid Dose) 50% (w/v)
4 (High Dose) 100% (w/v)

No. of animals per dose:

Main study: 5 females (nulliparous and non-pregnant)
Pre-test: 2 females

Details on study design:

RANGE FINDING TESTS:
Concentrations of 50 and 100 % of the test substance were tested by (epidermal) topical application on two mice on one ear each once daily each on three consecutive days. The animals were sacrificed on day 6.
In the pre-test the tested animals did not show any signs of systemic toxicity.
On day 4, the animal treated with the undiluted test item showed transiently a slightly reduced spontaneous activity. However relevant body weight loss did not occur during the course of the study. On days 3 to 6, the animal treated with 50% test item concentration showed an erythema of the ear skin (Score 1). The animal treated with 100% test item concentration showed an erythema of the ear skin as well (Score 1 on day 2, 3 and 6 and Score 2 on day 4 and 5. Furthermore, scabby ears were observed on day 5 in the animal treated with the undiluted test item.
Thus, the test item in the main study was assayed at 25, 50 and 100%. The highest concentration tested was the highest level that could be achieved whilst avoiding systemic toxicity and excessive local skin irritation as confirmed in the pre-experiment.

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 and for the DPM values (group mean DPM ± standard deviation).
The Dean-Dixon-Test and the Grubb's test were used for identification of possible outliers (performed with Microsoft Excel 2007). An outlier animal (animal l4) was detected in the Dean­ Dixon-Test but and in the Grubb's test but the outlier was not excluded from any subsequent calculations, as exclusion of the outlier would not change the overall test result.
However, both biological and statistical significance were considered together.

Results and discussion

Positive control results:

A positive control performed with alpha-Hexylcinnamaldehyd in October 2013 resulted in an S.I. of 1.8 at 5% (w/v)
alpha-Hexylcinnamaldehyd in acetone/olive oil (4+1, v/v), 3.2 at 10 % and 5.8 at 25 %. An EC3 of 9.3 % (w/v) was calculated.

In vivo (LLNA)

Results

Results 1

Parameter:

EC3

Value:

31.6

Test group / Remarks:

25%, 50%, 100%

Results 2

Parameter:

SI

Value:

2.74

Test group / Remarks:

25%

Results 3

Parameter:

SI

Value:

3.76

Test group / Remarks:

50%

Results 4

Parameter:

SI

Value:

5.72

Test group / Remarks:

100%

Any other information on results incl. tables

Calculation and Results of Individual Data

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

Test item concentration			DPM values measured	DPM-BG per animal (2 lymph nodes)^a)	S.I.^b)
%	Group no.	Animal no.
---	---	BG I	24	---	---
---	---	BG II	24	---	---
0	1	1	482	458.0	---
0	1	2	927	903.0	---
0	1	3	1007	983.0	---
0	1	4	1106	1082.0	---
0	1	5	1595	1571.0	---
25	2	6	2641	2617.0	2.6
25	2	7	2855	2831.0	2.8
25	2	8	2214	2190.0	2.2
25	2	9	3024	3000.0	3.0
25	2	10	3090	3066.0	3.1
50	3	11	3249	3225.0	3.2
50	3	12	2933	2909.0	2.9
50	3	13	2787	2763.0	2.8
50	3	14	6139	6115.0	6.1
50	3	15	3797	3773.0	3.8
100	4	16	8745	8721.0	8.7
100	4	17	4587	4563.0	4.6
100	4	18	6649	6625.0	6.6
100	4	19	4979	4955.0	5.0
100	4	20	3734	3710.0	3.7

1    =  Control Group

2-4=  Test Group

^a)   =  values corrected for mean background value (BGI and BGII)

^b)    =  Stimulation Indices relative to the mean of the control group (Group 1)

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

In this vaild Local Lymph Node Assay according to OECD 429 1,4-Butanediol dimethacrylate is a dermal sensitiser.
CLP EU GHS (Regulation (EC) No 1272/2008) classification: sensitizing category 1B (EC3 value > 2%)

Executive summary:

In this vaild dermal sensitisation study according to OECD Guideline 429 (adopted July 2010) 1,4 -Butanediol dimethacrylate (purity: 99.63%) in acetone:olive oil (4+1, v/v), groups of 5 female CBA/CaOlaHsd mice were tested using test item concentrations of 25, 50 and 100% using the LLNA method with the individual approach.

In this Local Lymph Node Assay 1,4 -Butanediol dimethacrylate is a dermal sensitiser.

A loss in body weight did not occur in the test item treated animals during the course of the study. No cases of mortality were observed.

All test item treated animals developed an erythema of the ear skin during the course of the observation period (animals treated with the undiluted test item: score 1 on days 2 and 6, score 2 on days 3 - 5; animals treated with 50% test item: score 1 on days 3 - 5; animals treated with 25% test item: score 1 on days 3 and 4).

STIMULATION INDICES (S.I.) of 2.74, 3.76 and 5.72 were determined with the test substance at concentrations of 25%, 50% and 100% in acetone:olive oil (4+1, v/v), respectively. A clear dose response was observed.

An outlier was identified in the group treated with 50% concentration of the test item (DPM value determined for animal number 14). Exclusion of the outlier led to a slight reduction in the corresponding S.I.for the mid dose group but was still above the threshold value of 3 for a positive response (S.I. of 3.17). The exclusion of the outlier did not change the overall test result and was thus not excluded from the calculations.

The positive control substance was α-Hexylcinnamaldehyde, which gave an EC3 at 9.3 % (w/v). A result is regarded as positive when the S.I. is ≥3.

Based on these criteria, the test substance was found to be a sensitiser. The EC3 was calculated to be 31.4 %.

In this study, 1,4 -Butanediol dimethacrylate is a dermal sensitiser.

CLP EU GHS (Regulation (EC) No 1272/2008) classification: sensitizing category 1B (EC3 value > 2%)

 

 

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