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Description of key information

CLP EU GHS (Regulation (EC) No 1272/2008) classification: sensitizing category 1B (EC3 value > 2%) according to an LLNA OECD 429 (2014)

Inconsistent in vivo data in guinea pigs with several test methods.

Overall suffient data to classify TREGDMA as weak skin sensitizer.

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
Study period:
06 November 2013 - 19 November 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
individual approach (adopted 22 July 2010)
Qualifier:
according to
Guideline:
EU Method B.42 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
dated May 30, 2008
GLP compliance:
yes (incl. certificate)
Type of study:
mouse local lymph node assay (LLNA)
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): 18.0 g - 22.2 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
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 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.
From day 3 up to day 6, the animal treated with 50% test item concentration showed an erythema of the ear skin (Score 1). On day 2, 3 and day 6 the animals treated with 100% of the test item showed an erythema of the ear skin (Score 1), and on day 4 and 5 an erythema of the ear skin (Score 2). In addition the ears were scabby on day 5 and 6. No excessive increase in ear weights and/or ear thickness values were observed.
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).
However, both biological and statistical significance were considered together.
Positive control results:
A positive control performed with alpha-Hexylcinnamaldehyd in October 2016 resulted in an S.I. of 1.5 at 5% (w/v)
alpha-Hexylcinnamaldehyd in acetone/olive oil (4+1, v/v), 3.84 at 10 % and 11.76 at 25 %. An EC3 of 8.2 % (w/v) was calculated.
Parameter:
EC3
Value:
91.6
Parameter:
SI
Value:
1.4
Test group / Remarks:
25%
Parameter:
SI
Value:
1.51
Test group / Remarks:
50%
Parameter:
SI
Value:
3.3
Test group / Remarks:
100%
Parameter:
other: disintegrations per minute (DPM)
Remarks on result:
other: Vehicle control group (negative control with vehicle, only): 999.4 DPM per lymph node (2 lymph nodes) Test substance 25% DPM/lymph node: 1398.8 50% DPM/lymph node: 1510.2 100% DPM/lymph node: 3296.8

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

1925

1901.0

1.9

25

2

7

1563

1539.0

1.5

25

2

8

1710

1686.0

1.7

25

2

9

1116

1092.0

1.1

25

2

10

800

776 .0

0.8

50

3

11

760

736.0

0.7

50

3

12

1918

1894.0

1.9

50

3

13

1625

1601.0

1.6

50

3

14

1823

1799.0

1.8

50

3

15

1545

1521.0

1.5

100

4

16

3100

3076.0

3.1

100

4

17

5249

5225.0

5.2

100

4

18

2036

2012.0

2.0

100

4

19

3746

3722.0

3.7

100

4

20

2473

2449.0

2.5

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)

Interpretation of results:
sensitising
Conclusions:
In this vaild Local Lymph Node Assay according to OECD 429 Triethyleneglycol 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) Triethyleneglycol dimethacrylate (purity: 99.68%) in acetone:olive oil (4+1, v/v), groups of 5 female CBA/CaOlaHsd mice were tested using the LLNA method with the individual approach.

In this Local Lymph Node Assay Triethyleneglycol dimethacrylate is a dermal sensitiser.

 

No systemic findings were observed during the study period. Only the highest dose (100%) induced slight erythema on the ear skin on days 3 to 6 (Score 1). Animals treated with 25 and 50% of the test item did not show any signs of local skin irritation.

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. No cases of mortality were observed.

STIMULATION INDICES (S.I.) of 1.40, 1.51 and 3.30 were determined with the test substance at concentrations of 25%, 50% and 100% (w/v) in acetone:olive oil (4+1, v/v), respectively. 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 91.6 %.

In this study, Triethyleneglycol dimethacrylate is a dermal sensitiser.

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

 

 

NOTE: Any of data in this dataset are disseminated by the European Union on a right-to-know basis and this is not a

publication in the same sense as a book or an article in a journal. The right of ownership in any part of this information is

reserved by the data owner(s). The use of this information for any other, e.g. commercial purpose is strictly reserved to the

data owners and those persons or legal entities having paid the respective access fee for the intended purpose.

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

Non-human information

In a mouse local lymphnode assay, LLNA (MPA, 2014), TREGDMA formulated in acetone/olive oil (4+1 v/v), was assessed for its possible skin sensitising potential using test item concentrations of 25, 50 and 100 %. All treated animals survived the scheduled study period and no signs of systemic toxicity were observed. Only the highest dose of 100% induced slight erythema on the ear skin on days 3 to 6 (Score 1). Animals treated with 25 and 50% of TREGDMA did not show any signs of local skin irritation. 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 this strain and age.

Stimulation Indices (S. I.) of 1.40, 1.51 and 3.30 were determined with TREGDMA at concentrations of 25, 50 and 100%. The test item TREGDMA was found to be a skin sensitiser with weak potency due to the derived EC3 value of 91.6 % (w/v).

Furthermore there are six publications (Klimisch score 2; reliable with restrictions) available for the sensitising potential of TREGDMA:

 

Magnusson-Kligman (GPMT), Intradermal 5% soybean oil or soy bean oil/2-butanone 1:2; epicutaneous induction: 100%; challenge: 25% in petrolatum and 100%

Sensitising (9/20 and 3/20 +ve)

Clemmensen, 1984

Magnusson-Kligman (GPMT), intradermal induction: 5%; epicutaneous induction: 100%; challenge: 1% and 5% in olive oil

Sensitising (6/20 and 15/20 +ve)

Cavelier et al. 1981

Magnusson-Kligman (GPMT), intradermal induction: 1% in AOO; epicutaneous induction: 50% in pet.; challenge: 1% in petrolatum

Not sensitising (1/15 +ve)

Bjoerkner 1984

GPMT, intradermal induction: 1% in liq. paraffin; epicutaneous induction: 100%; challenge: 25% in liq. paraffin

Not sensitising

Huntingdon 1973 for Loctite

Polak-Test; d0: 4 footpad injections, 1 nape injection (0.1 mL of 2 mg/mL emulsion); d7: open skin test (repeated weekly for up to 12 weeks)

Not sensitising

Parker and Turk, 1983

Non-standard protocol, mix of repeated epicutaneous and intradermal induction, partly w. FCA; challenge w. 1 % and 98 %

Not sensitising

Dupont, 1969

 

The available GPMT tests used intradermal induction procedures which are considered to be less relevant for this substance as dermal penetration of TREGDMA under normal use conditions is expected to be low.

The weak sensitizing potential of TREGDMA is confirmed by the negative results obtained in four studies with standard induction concentrations of 1 %. Positive results were obtained in two studies with induction concentrations as high as 5 %.

Skin sensitisation is an immunological process consisting of an induction phase and the subsequent immune reaction. Key steps in the induction phase are penetration of the substance to the viable epidermis, protein binding (haptenation), release of proinflammatory signals by keratinocytes, activation and maturation of dentritic cells and migration of dentritic cells to the draining lymph nodes (OECD, 2012).

Thus, skin penetration is a prerequisite for skin sensitisation. Based on a reliable QSAR model for dermal absorption only low dermal penetration is expected for TREGDMA:

The dermal absorption (steady-state flux) of TREGDMA has been estimated by calculation using the principles defined in the Potts and Guy prediction model. Based on a molecular weight of 286.32 g/mol and a log Kow of 2.3, the predicted flux of TREGDMA is 4.989 μg/cm²/h. The relative dermal absorption is expected to be low.

Moreover, metabolism data show that the substance is rapidly metabolised by unspecific carboxyl hydrolases with hydrolysis half-lives in the range of minutes. The metabolites, methacrylic acid and triethylene glycol are not sensitising.

Intradermal injection of the substance for induction as performed in the available publications, however, bypasses the intact skin barrier and a large part of the capacity of intact skin for ester hydrolysis. In a study with lower alkyl methacrylates, Jones (2001) has demonstrated that intact skin has a significant capacity for hydrolysis if methacrylate esters.

In conclusion, the data available to the public so far do not take into account the low dermal penetration potential of the substance.

The more relevant model to assess the skin sensitisation potential of TREGDMA is the Local Lymph Node Assay as in this assay the skin is left intact. Thus, a Local Lymph Node Assay was conducted. The results of the LLNA test showed a weak positive reaction towards TREGDMA. In conclusion, TREGDMA has to be classified as a dermal skin sensitiser.

 

There is no information available for respiratory sensitisation. Therefore, there is a data gap in this respect. However, the data gap cannot be fulfilled with experimental data, since there is no internationally accepted animal model for respiratory sensitisation. In case human data for respiratory sensitisation emerges, this will be taken into account.

Reference

OECD (2012) The Adverse Outcome Pathway for Skin Sensitisation Initiated by Covalent Binding to Proteins Part 1: Scientific Evidence, Series on Testing and Assessment No.168, ENV/JM/MONO(2012)10/PART1, available online: http://www.oecd.org/env/ehs/testing/seriesontestingandassessmentnon-testingmethodsegqsarandgrouping.htm

 

Compliance to REACh requirements

he requirements are covered with reliable in vivo data, performed with the substance itself and before in vitro testing became current priority.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

No cases of respiratory allergy have been reported in the literature for TREGDMA.

There is no evidence in the literature that exposure to the members of the Multifunctional Methacrylates (MfMA category) has been associated with respiratory allergy.

There is no evidence in the literature that exposure to TREGDMA has been associated with respiratory allergy.
Inhalation is no relevant route of exposure.

Justification for classification or non-classification

Comparison with criteria

According to the CLP criteria, a substance should be classified as sensitising when there are positive results from appropriate animal tests (a response of at least 30 % of the animals in an adjuvant-type test).

In a local lymphnode assay acc. OECD guideline 429 with GLP at concentrations of 25, 50 and 100 % stimulation indices of 1.40, 1.51, and 3.30 were determined as well as an EC3 value of 91.6 % (w/v). Also TREGDMA showed positive response in two studies in Guinea pig maximisation test (GPMT), non-GLP.

In conclusion, TREGDMA is considered as weak sensitizing to skin.

Conclusions on classification and labelling

The classification of TREGDMA was reconsidered based on the positive outcome of a Local Lymph Node Assay performed by MPA, 2014. Therefore TREGDMA has to be classified as a skin sensitiser (Skin Sensitiser Cat.: 1B; H317) according to regulation CLP regulation 1272/2008/EC and UN-GHS.

Based on the available data there is no evidence that TREGDMA causes respiratory sensitisation. Therefore, a classification for respiratory sensitisation is considered as not justified.