Registration Dossier

Administrative data

Description of key information

1,3-Butanediol dimethacrylate is considered as skin sensitizer due to the reliable results of a valid OECD 429 GLP study done with the analogous substance 1,4 -butanediol dimethacrylate (Klimisch score: 1, reliabity without restrictions, MPA, 2014).

In his study, the EC3 was calculated to be 31.4 %.

Further data on skin sensitization performed with the analogous substance 1,4 -butanediol dimethacrylate

are as follows.

Freund's complete adjuvant test (RL2): sensitising; non-GLP; intradermal induction: 13% in methyl ethyl ketone:arachis oil 2:1, challenge: 78% in methyl ethyl ketone:arachis oil 2:1; minimum non-irritating concentration 78%

Guinea Pig Maximisation Test (RL2): not sensitising; non-GLP; intradermal induction: 13% in methyl ethyl ketone:arachis oil 2:1, epicutaneous induction: undiluted, challenge+rechallenge: 26% in methyl ethyl ketone:arachis oil 2:1; minimum non-irritating concentration 26%

Guinea Pig Maximisation Test (RL2): not sensitising; non-GLP; intradermal induction: 2% in olive oil:acetone 9:1, topical induction: 50% in petrolatum (pretreatment with 10% SLS in petrolatum), challenge+rechallenge: 1% in petrolatum

The overall conclusion for 1,3 -BDDMA is: sensitising

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
Guideline:
OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)
Version / remarks:
individual approach (adopted 22 July 2010)
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)
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
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.
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.
Parameter:
EC3
Value:
31.6
Test group / Remarks:
25%, 50%, 100%
Parameter:
SI
Value:
2.74
Test group / Remarks:
25%
Parameter:
SI
Value:
3.76
Test group / Remarks:
50%
Parameter:
SI
Value:
5.72
Test group / Remarks:
100%

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)

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%)

 

 

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:

No relevant studies are available for 1,3 –BDDMA as such. However, three, reliable (Klimisch score 2; reliable with restrictions) publications are available on the sensitising potential of the analogous isomer 1,4-BDDMA and, most important, one recently performed Local Lymph Node Assay (LLNA) with 1,4-BDDMA according to OECD 429 (Klimisch score 1, reliable without restrictions, GLP, MPA, 2014).

 

In this study, 1,4 -Butanediol dimethacrylate (purity: 99.63%) in acetone: olive oil (4+1, v/v), was administered to groups of 5 female CBA/CaOlaHsd mice at test item concentrations of 25, 50 and 100% using the LLNA method with the individual approach.

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.

The EC3 was calculated to be 31.4 %. Therefore, 1,4 -Butanediol dimethacrylate was classified as a dermal sensitiser.

In addition, there are three relevant (Klimisch score 2; reliable with restrictions) publications available on the sensitising potential of 1,4-BDDMA providing equivocal results (positive and negative findings were reported):

In a dermal sensitisation study with 1,4-BDDMA (97%), 10 female Dunkin-Hartley guinea pigs were tested using the Freund's complete adjuvant test (Van der Walle 1983).

The following concentrations were used:

intradermal induction: 0.5 M in Aramek (methyl ethyl ketone:arachis oil 2:1) (corresponding to 13% according to the study authors)

challenge: 3 M in Aramek (methyl ethyl ketone:arachis oil 2:1) (corresponding to 78% according to the study authors)

After challenge on day 21, 8/8 animals were sensitised, after rechallenge on day 35 5/8 animals were positive. Therefore, 1,4-BDDMA is a dermal sensitiser in this study.

 

In a dermal sensitisation study with 1,4-BDDMA (97%), 10 female Himalayan white spotted guinea pigs were tested using the method of Magnusson & Kligman (Guinea Pig Maximisation Test).In a pretest the maximum non-irritating concentration was determined to be 1 M (corresponding to 26%; Van der Walle 1983).

The following concentrations were used in this sensitisation study:

intradermal induction: 0.5 M methyl ethyl ketone:arachis oil 2:1 (corresponding to 13% according to the study authors)

epicutaneous induction: undiluted

challenge: 1 M in methyl ethyl ketone:arachis oil 2:1 (corresponding to 26% according to the study authors) After challenge on day 21 0/10 animals were sensitised, after rechallenge on day 35 2/10 animals were positive. According to the authors, a third challenge has been performed on day 49 which confirmed the results auf the second challenge, but the data are not shown in the publication.

Only 10 animals were used in this study instead of 20 as recommended in the OECD guideline.

 

In a further dermal sensitisation study with 1,4-BDDMA (min. 95%), 10 female Dunkin-Hartley guinea pigs were tested using the method of Magnusson & Kligman (Guinea Pig Maximisation Test; Björkner 1984).

The optimal concentrations for intradermal and topical induction and challenge have been determined in animals not participating in the sensitisation procedure. However, the results of the pre-test are not shown in this publication.

The following concentrations were used:

intradermal induction: 2% in olive oil:acetone 9:1

topical induction: 50% in petrolatum (pretreatment with 10% Sodium lauryl sulphate [SLS] in petrolatum)

challenge, rechallenge: 1% in petrolatum

48 h after the first challenge application, the animals received a booster dose intradermally on the neck (2% in olive oil:acetone 9:1, without Freund’s complete adjuvant). The animals were rechallenged one week after the first challenge.

0/10 animals were sensitised in this test. It is not documented whether the scores were obtained after first or second challenge. It is assumed that the highest response rates for any of the challenge times were reported.

In another maximisation test (Clemmensen, 1984), which has been reported as a supporting study, guinea pigs were induced with 5 % 1,4 -BDDMA in soy bean oil or 2 -butanone/soy bean oil 2:1 in the intradermal injection and 100 % in the occlusive epicutaneous exposure. In the challenge phase, 100 % were used in the occlusive epicutaneous exposure after 21 and 35 days.1,4 -BDDMA was not a sensitiser in this test.

Considerations

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 1,4 -BDDMA:

The dermal absorption (steady-state flux) of 1,4 -BDDMA has been estimated by calculation using the principles defined in the Potts and Guy prediction model. Based on a molecular weight of 226.27 g/mol and a log Kow of 3.1, the predicted flux of 1,4 -BDDMA is 2.895μg/cm²/h; the relative dermal absorption is 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 1,4-butanediol are not sensitising.

Intradermal injection of the substance for induction as performed in the available publications (Weight of evidence studies, three puplications, Klimisch score 2, non GLP, reliable with restrictions) provided equivocal results as positive and negative findings were reported. However, the respective treatments bypass the intact skin barrier and does not take into account the low dermal penetration potential of the substance.

Thus, a more relevant model to assess the skin sensitisation potential of 1,4-BDDMA is the Local Lymph Node Assay as in this assay the skin is left intact. Accordingly, a Local Lymph Node Assay was conducted. Based on the new reliable data of this Local Lymphnode Assay with 1,4-Butanediol dimethacrylate according to OECD 429 (MPA, 2014) 1,4-Butanediol dimethacrylate is expected to be a skin sensitiser. Thus 1,4-BDDMA is considered to be a skin sensitiser. By analogy, this is considered true also for 1,3-BDDMA (read across justified in the category document.

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

 

Justification for selection of skin sensitisation endpoint:

No relevant studies are available for 1,3 -BDDMA. Instead three relevant, reliable (Klimisch score 2; reliable with restrictions) publications are available for the sensitising potential of the analogous substance 1,4-BDDMA and one new reliable Local Lymph Node Assay with 1,4-BDDMA according to OECD 429 (Klimisch score 1, reliable without restrictions, GLP, MPA, 2014) is available. Since the more relevant model to assess the skin sensitisation potential of 1,3-BDDMA is the Local Lymph Node Assay as in this assay the skin is left intact. This assay was chosen as key study for the sensitising potential of 1,3-BDDMA.

 

Compliance to REACh requirements

The requirements are covered with reliablein vivodata, performed with the analogous substance 1,4-BDDMA and beforein vitrotesting became current priority.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:

Justification for selection of respiratory sensitisation endpoint:
Inhalation is no relevant route of exposure.

Justification for classification or non-classification

Due to the new results of the valid Local Lymph Node key study (MPA, 2014) obtained with the analogous isomer 1,4-BDDMA the sensitising potential of both isomers of BDDMA was reconsidered. Based on the positive outcome of the new LLNA assay with 1,4-BDDMA, both isomers 1,3- and 1,4-BDDMA are classified as skin sensitiser category 1B according to regulation (EC) 1272/2008.