Benzyl methacrylate

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-10-19 to 2011-12-27

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

With acceptable restrictions. limit test, GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Version / remarks:

adopted 30 May 2008

Deviations:

yes

Remarks:

3 animals were subject to reduced exposure time ranging between >4 to 24 hours

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Version / remarks:

adopted 24th Feb, 1987

Deviations:

yes

Remarks:

3 animals were subject to reduced exposure time ranging between >4 to 24 hours

GLP compliance:

yes (incl. QA statement)

Remarks:

Certificate dated 6 April 2009

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Benzyl methacrylate

EC Number:

219-674-4

EC Name:

Benzyl methacrylate

Cas Number:

2495-37-6

Molecular formula:

C11H12O2

IUPAC Name:

benzyl methacrylate

Test material form:

liquid

Specific details on test material used for the study:

- Name of test material (as cited in study report): Benzyl methacrylate

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- WISTAR rats Crl:WI(Han) (full barrier)
- Age at study initiation: males: approx. 13 weeks, females: approx. 14 weeks
- Weight at study initiation: males: 250-267 g, females: 205-223 g
- Fasting period before study: no
- Housing: separate IVC cages, type III H, polysulphone cages on Altromin saw fibre bedding, full barrier in air-conditioned room
- Diet (e.g. ad libitum): Altromin 1324 maintenance diet for rats and mice, ad libitum
- Water (e.g. ad libitum): tap water, sulphur acidified to a pH value of approx. 2.8 (drinking water, municipal residue control, microbiological controls at regular intervals), ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): 55 ± 10%
- Air changes (per hr): 10/hr
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: 2011-09-20 to 2011-11-10

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

TEST SITE
- Area of exposure: dorsal area of the trunk
- % coverage: 10
- Type of wrap if used: gauze-dressing with non-irritating tape, fixed with additional dressing in suitable manner.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): tap water
- Time after start of exposure: 24 h

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2000 mg/kg bw
- Concentration (if solution): n/a (undiluted)
- Constant volume or concentration used: yes (single dose)

Duration of exposure:

24 h (except for 3 test animals which unwrapped themselves overnight, leading to a shortened application period of 4 to 24 hours)
For the animals which unwrapped themselves, no signs of toxicity and significant dermal irritation were observed. As at the 4 h control observation the dressing was tight on all animals, it is very likely that the 3 animals unwrapped themselves clearly after the 4 h period. It can be expected that these animals have been exposed to the test item partially also by the oral route, while grooving, in addition to the dermal route.
It is concluded that the abbreviated exposure period has no effect on the overall result and the classification of the test item, and that a sufficient estimation of the dermal toxicity is ensured.
The validity of the study is not affected and according to animal welfare reasons it was decided not to repeat the study.

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: clinical observation several times on day of dosing (at least once during first 30 minutes and with special attention given during the first 4 hours post-dose). Symptoms were recorded as soon as noticed. Thereafter, daily observations for clinical signs until end of observation period. All abnormalities were recorded. Animals were weighed on day 1 (prior to application of dose) and on day 8 and 15.
- Necropsy of survivors performed: yes
- Other examinations performed:
-- In case of gross pathological changes, tissues were preserved for a possible histopathological evaluation.
-- The treated areas of skin were examined daily for signs of primary skin irritation. Signs of erythema and oedema were assessed using the scoring system laid down in OECD Guideline 404, adopted 24th April 2002.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

act. ingr.

Mortality:

All animals survived until the end of the observation period of 14 days.

Clinical signs:

other: No signs of systemic toxicity were observed

Gross pathology:

With the exception of acute injection of blood vessels in the abdominal region, which is due to the euthanasia injection, no specific gross pathological changes were recorded for any animal.

Other findings:

Signs of irritation:
- very slight erythema (grade 1, reversible within 8 days) was observed in 1/5 females on days 4, 5, and 7; this animal showed also eschar (up to day 10) and desquamation (up to day 12)
- eschar, desquamation and scratches were observed in one further female, without leading to scoring
- all effects were reversible within 13 days - females with reduced exposure time due to unwrapping showed either no effects or only non-scored eschar (day 5 to 7) or scratches (day 7)
- No skin irritation was observed at the males.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

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

Conclusions:

The LD50-value for acute dermal toxicity of the test substance BNMA is > 2000 mg/kg bw.

Executive summary:

In an acute dermal toxicity study according to OECD guideline 402 (adopted 24th Feb, 1987), EU Method B.3 (adopted 30 May 2008), 5 male and 5 female young adult WISTAR Crl: WI(Han) rats were dermally exposed to BNMA (98.37%) for 24 hours under a semiocclusive dressing to approx. 10% of body surface area at doses of 2000 mg/kg bw. Animals then were observed for 14 days.

No animal died. Erythema grade 1 was observed in 1 of 5 female animals. Eschar and scratches were observed in 3 of 5 female animals. Desquamation was observed in 2 of 5 female animals. No signs of irritation were found for the male animals. All signs of irritation were reversible within the observation period. No clinical signs of systemic toxicity were observed. Weight gain was positive and within normal range, except for 3 female rats which temporarily lost weight in the first week. No macroscopic substance related pathologic organ findings were noted during necropsy.

Dermal LD₅₀

Males > 2000  mg/kg bw

Females > 2000  mg/kg bw

Combined > 2000  mg/kg bw

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