Benzyl methacrylate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records

Reference

Reference 1

Endpoint:

skin sensitisation: in vivo (LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-01-16 to 2007-02-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 24 April 2002

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

certificate dated 6 January 2005

Type of study:

mouse local lymph node assay (LLNA)

Specific details on test material used for the study:

Name of test material (as cited in study report): Benzyl methacrylate; 2-Propenoic acid, 2-methyl-, benzenemethyl ester

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- CBA/CaOlaHsd mice, nulliparous, non-pregnant
- Age at study initiation: 7-8 weeks (at beginning of acclimatisation)
- Weight at study initiation: 18.9 g ± 1.2 g
- Housing: single; Makrolon Type I, with wire mesh top
- Diet (e.g. ad libitum): pelleted standard, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C ± 3°C
- Humidity (%): 30-72%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: From: 2007-02-07 To: 2007-02-13

Vehicle:

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

Concentration:

-non-GLP pretest (test substance): 12.5%; 25%; 50%; 100%
-Main study (test substance): 25%; 50%; 100%
-Positive control: α-Hexylcinnamaldehyde in acetone: olive oil (4+1)
-Negative control: vehicle

No. of animals per dose:

4 female mice

Details on study design:

RANGE FINDING TESTS:
Concentrations were tested on two mice on one ear each.
- Compound solubility:
in water: virtually insoluble at 20°C
in vehicle: miscible with most organic solvents
- Irritation: no irritation effects were observed at any concentration after single application (even not at 100%).
- Lymph node proliferation response: no data

MAIN STUDY

TREATMENT PREPARATION AND ADMINISTRATION:
Each group of mice was treated by topical (epidermal) application to the dorsal surface of each ear lobe (left and right) with different test item concentrations of 25, 50 and 100% (w/v) in acetone: olive oil (4+1). The application volume (25 µL) was spread over the entire dorsal surace (diam. approx. 8 mm) of each ear lobe once daily for three consecutive days. The control group of mice was treated with an equivalent volume of the vehicle alone.
5 days after the 1st topical application, all mice were administered with 250 µL of 80.5 µCi/mL 3HTdR (=20.13 µCi 3HTdR per mouse) by intravenous injection via a tail vein. 5 hours after this injection, all mice were euthanised.
The draining lymph nodes were excised and pooled per group (8 nodes per group). Single cell suspensions (in phosphate buffered saline) of pooled lymph node cells were prepared by gentle mechanical disaggregation through stainless steel gauze (200 µm mesh size). After washing two times with phosphate buffered saline (approx. 10 mL) the lymph node cells were resuspended in 5% trichloroacetic acid (approx. 3 mL) and incubated at approx. +4°C for at least 18 hours for precipitation of macromolecules. The precipitates were then resuspended in 5% trichloroacetic acid (1 mL) and transferred to plastic scintillation vials with 10 mL scintilation liquid and thoroughly mixed.
The level of 3HTdR incorporation was then measured on a β-scintillation counter. Similarly, background 3HTdR levels were also measured in two 1 mL-aliquots of 5% trichloroacetic acid. The β-scintillation counter expresses 3HTdR incorporation as the number of radioactive disintegrations per minute (DPM).
The proliferate response of lymph node cells is expressed as DPM/node and as the ratio of 3HTdR incorporated into lymph node cells of test lymph nodes relative to that recorded for control lymph nodes (stimulation index). Before DPM/node values were determined, mean scintillation background DPM was subtracted from test and control raw data. Background DPM was measured with a duplicate set of 1 mL 5% trichloroacetic acid.

CRITERIA USED TO CONSIDER A POSITIVE RESPONSE::
Two criteria needed to be fulfilled:
(1) exposure to at least one concentration of the test item resulted in incorporation of 3H-methyl thymidine (3HTdR) being at least 3-fold or greater than that recorded in control mice, as indicated by the stimulation index (based on investigations performed with a wide range of chemicals, the indication of sensitizing activity was set to S.I.=3)
(2) data are compatible with conventional dose response (although allowance must be made (especially. at high topical concentrations) for either local toxicity or immunological suppression)

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Statistics:

none

Positive control results:

A positive control performed with alpha-Hexylcinnamaldehyd in December 2006 resulted in an S.I. of 2.04 at 5% (w/v) alpha-Hexylcinnamaldehyd, 6.31 at 10% and 12.45 at 25%. An EC3 of 6.1% (w/v) was calculated.

Parameter:

SI

Value:

4.28

Test group / Remarks:

25 %

Remarks on result:

other: EC3 could not be calculated due to all S.I. being above 3.

Parameter:

SI

Value:

6.92

Test group / Remarks:

50 %

Remarks on result:

other: EC3 could not be calculated due to all S.I. being above 3.

Parameter:

SI

Value:

6.57

Test group / Remarks:

100 %

Remarks on result:

other: EC3 could not be calculated due to all S.I. being above 3.

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: Vehicle control group (negative control with vehicle, only): 794.2 DPM per lymph node (8 lymph nodes of pooled animals of a dose group assessed) Test substance: 25% DPM/lymph node: 3403 50% DPM/lymph node: 5498.5 100% DPM/lymph node: 5219.6

Interpretation of results:

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

Conclusions:

In this local lymphnode assay Benzyl methacrylate is a dermal sensitiser and attained the criteria of Skin sens Category 1 B.

Executive summary:

In a dermal sensitisation study according to OECD Guideline 429 (adopted 24 April 2002) with BNMA in acetone:olive oil (4+1, v/v), groups of 4 female CBA/CaOlaHsd mice were tested using the LLNA method.

STIMULATION INDICES (S.I.) of 4.28, 6.92 and 6.57 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 6.1% (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 at any concentration tested. However, the EC3 could not be calculated due to all calculated S.I.s being above 3. Accordingly, the EC3 is estimated to be below a concentration of the test substance of 25% (w/v).

In this local lymphnode assay Benzyl methacrylate is a dermal sensitiser and attained the criteria of Skin sens Category 1 B.

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.

Reference 2

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1984-03-23 to 1984-04-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

With acceptable restrictions. GLP.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Version / remarks:

adopted 12 May 1981

GLP compliance:

yes

Type of study:

guinea pig maximisation test

Specific details on test material used for the study:

- Name of test material (as cited in study report): Methacrylate de Benzyle (MABz)

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- albino Dunkin-Hartley guinea pigs
- Age at study initiation: ca. 5 to 8 weeks
- Weight at study initiation: 278 – 382 g
- Housing: in groups of up to four in solid-floor polypropylene cages furnished with softwood shavings
- Diet (e.g. ad libitum): standard laboratory guinea pig diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: min. 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.5 ± 3.5°C
- Humidity (%): 45-60%
- Air changes (per hr): ca. 10
- Photoperiod (hrs dark / hrs light): 12/12

Route:

intradermal and epicutaneous

Vehicle:

other: arachis oil for intradermal injections; abs. ethanol for topical application

Concentration / amount:

- 5% for intradermal induction
- 100% for epicutaneous induction
- 100% for epicutaneous challenge

Route:

epicutaneous, occlusive

Vehicle:

other: arachis oil for intradermal injections; abs. ethanol for topical application

Concentration / amount:

- 5% for intradermal induction
- 100% for epicutaneous induction
- 100% for epicutaneous challenge

No. of animals per dose:

10 for test substance, 10 for negative control

Details on study design:

RANGE FINDING TESTS:
- intradermal injection of 0.1 mL of 1% and 5% test substance in arachis oil (one guinea pig/concentration)
- observation after 24, 48, 72 h and 7 days for signs of toxicity and necrosis

- topical application of 50% (vehicle: abs. ethanol) and 100% for 24 h (4 guinea pigs, each treated with 50% and 100%)
- observation after patch removal: 1, 24, 48 h for signs of irritation

MAIN STUDY
A. INDUCTION EXPOSURE
Intradermal induction
- No. of exposures: 1
- Exposure period: n/a
- Test groups: test substance
- Control group: vehicle (arachis oil)
- Site: shoulder region, pairwise injections
- Frequency of applications: 1x
- Concentrations:
0.1 mL Freund’s complete adjuvant (FCA)
0.1 mL 5% test substance (or vehicle only in control)
0.1 mL 50:50 mixture of 5% test substance (or vehicle only in control) and FCA

Topical induction
- No. of exposures: 1
- Exposure period: 48 h
- Test groups: 100% test substance
- Control group: vehicle (abs. ethanol)
- Site: shoulder region, same as for intradermal injections
- Concentrations: 100% test substance (or vehicle in control)
- No pretreatment to create local skin irritation was done before epicutaneous induction.

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: day 21
- Exposure period: 24 h
- Test groups: 100% test substance (right), vehicle (left)
- Control group: 100% test substance (right), vehicle (left)
- Site: flanks
- Concentrations: 100%
- Evaluation (hr after challenge): 24 h, 48 h

Challenge controls:

yes, vehicle only (abs. ethanol)

Positive control substance(s):

not specified

Remarks:

sensitivity is of the strain is regularly checked in the laboratory

Positive control results:

no data; sensitivity is of the strain is regularly checked in the laboratory

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. No with. + reactions: 0.0. Total no. in groups: 10.0.

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

scattered mild redness

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. No with. + reactions: 1.0. Total no. in groups: 10.0. Clinical observations: scattered mild redness.

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

No. with + reactions:

0

Total no. in group:

10

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. No with. + reactions: 0.0. Total no. in groups: 10.0.

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

scattered mild redness

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. No with. + reactions: 1.0. Total no. in groups: 10.0. Clinical observations: scattered mild redness.

Dose range finding test:

- Intradermal application:

-- 1 % and 5 %: no evidence of necrosis or systemic toxicity

- Topical application:

-- 100 % (undiluted) and 50%: 2/4 animals showed 1 hour after removal of patches skin reactions score 1 (scattered mild redness), which were fully reversible at the second evaluation 24 hours after patch removal.

Main study:

- Induction: no documentation of reactions

- Challenge: One animal in the test group showed scattered mild redness (score 1) after 24 h and 48 h.

Interpretation of results:

GHS criteria not met

Remarks:

Criteria used for interpretation of results: other: CLP, EU GHS (Regulation (EC) No 1272/2008)

Conclusions:

BNMA is not a dermal sensitiser in this study.

Executive summary:

In a dermal sensitization study similar to OECD guideline 406 (adopted 12 May 1981) with BNMA (no information on purity), 10 young adult female Dunkin-Hartley guinea pigs were tested using the method of Magnusson & Kligman (Guinea Pig Maximisation Test).

Test concentrations were selected based on pretest results.For the intradermal and epicutaneous induction procedure concentrations of 5 % in arachis oil and 100 % were used, respectively. The test article concentration for the challange procedure was 100 %. No pretreatment to create local skin irritation was done before epicutaneous induction

A single animal in the test group showed scattered mild redness (score 1) at the 24 h and 48 hour readings. No reactions were observed at the test material challenge site in any of the control group animals at either the 24 or 48 hour readings. No reactions were seen at the control sites of any of the test or control group animals.

The test material produced a response in 10% of animals. According to CLP, EU GHS (Regulation (EC) No 1272/2008), a response of at least 30 % of the test animals of an adjuvant type guinea pig test method for skin sensitisation is considered as positve.

BNMA is not a dermal sensitiser in this study.

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:

Two reliable (RL1 -2), relevant and adequate studies are available to assess the sensitising potential of BNMA, a Local Lymph Node Assay in mice and a Guinea Pig Maximisation Test.

 

In a dermal sensitisation study according to OECD Guideline 429 (adopted 24 April 2002) with BNMA in acetone:olive oil (4+1, v/v), groups of 4 female CBA/CaOlaHsd mice were tested using the LLNA method.

STIMULATION INDICES (S.I.) of 4.28, 6.92 and 6.57 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 6.1% (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 at any concentration tested. However, the EC3 could not be calculated due to all calculated S.I.s being above 3. Accordingly, the EC3 is estimated to be below a concentration of the test substance of 25% (w/v).

In this study, BNMA is a dermal sensitiser.

 

In a dermal sensitisation study similar to OECD guideline 406 (adopted 12 May 1981) with BNMA (no information on purity), 10 young adult female Dunkin-Hartley guinea pigs were tested using the method of Magnusson & Kligman (Guinea Pig Maximisation Test).

Test concentrations were selected based on pretest results.For the intradermal and epicutaneous induction procedure concentrations of 5 % in arachis oil and 100 % were used, respectively. The test article concentration for the challange procedure was 100 %. No pretreatment to create local skin irritation was done before epicutaneous induction

A single animal in the test group showed scattered mild redness (score 1) at the 24 h and 48 hour readings. No reactions were observed at the test material challenge site in any of the control group animals at either the 24 or 48 hour readings. No reactions were seen at the control sites of any of the test or control group animals.

The test material produced a response in 10% of animals. According to CLP, EU GHS (Regulation (EC) No 1272/2008), a response of at least 30% of the test animals of an adjuvant type guinea pig test method for skin sensitisation is considered as positve. BNMA is not a dermal sensitiser in this study.

 

Considering all available data, BNMA is a dermal sensitiser. Although no exact EC3 can be determined from the LLNA due to the fact that all stimulation indices were above 3, it can be judged based on the dose-response curve that the EC3 will most probably be above a substance concentration of 2%. Thus, BNMA can be regarded as sensitiser of low to moderate potency.

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.

Short description of key information:
Local Lymph Node Assay: sensitising; OECD guideline 429, GLP; S.I. of 4.28, 6.92 and 6.57 at 25%, 50% and 100% (w/v) in acetone:olive oil; EC3<25%

Justification for selection of skin sensitisation endpoint:
The Local Lymph Node Assay (OECD guideline study; GLP) has been selected as key study as this is the preferred method for the assessment of sensitisation potential.

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

Based on the available data, BNMA has to be classified as dermal sensitiser, sub-category 1B according to the criteria given in regulation (EC) 1272/2008. Although no exact EC3 can be determined due to the fact that all stimulation indices were above 3, it can be judged based on the dose-response curve, that the EC3 will most probably be above a substance concentration of 2%. Thus, BNMA can be regarded as sensitiser of low to moderate potency.