Benzyl methacrylate

Endpoint summary

Description of key information

In an OECD Guideline 422 and GLP study with Benzyl methacrylate, the NOAEL for repeated dose toxicity is determined to 500 mg/kg/day which was the highest dose tested. Moreover, there is sufficient information to confirm the absence of a critical potential by read across to data on structurally related substances and the relevant metabolites methacrylic acid, benzyl alcohol and benzoic acid.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1 June 2012 to 21 July 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Version / remarks:

adopted 22 March 1996.

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Identity : Benzyl methacrylate
Alternative names : VISIOMER® BNMA; Benzylmethacrylat
CAS number : 2495-37-6
EINECS number : 219-674-4

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

A total of 90 Sprague Dawley [Crl:CD(SD)BR] rats (45 males and 45 virgin females), 7 to 8 weeks old and weighing 211-232 g for males and 135-199 g for females, were received from Charles River Italia S.p.A., Calco (Lecco), Italy.
After arrival the weight range for each sex was determined and the animals were temporarily identified within the cage by means of a coloured mark on the tail. A health check was then performed by a veterinarian.
An acclimatisation period of 14 days was allowed before the start of treatment, during which time the health status of the animals was assessed by thorough observations.

Animal room controls were set to maintain temperature and relative humidity at 22°C  2°C and 55%  15% respectively; actual conditions were monitored, recorded and the records retained. No relevant deviations from these ranges were recorded during the study. There were approximately 15 to 20 air changes per hour and the rooms were lit by artificial light for 12 hours each day.

In-life data from: 24 May 2012 to 21 July 2012

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

The test item was administered orally by gavage at a dose volume of 5 mL/kg body weight. Control animals received the vehicle alone at the same dose volume.

The required amount of Benzyl methacrylate was suspended in the vehicle (corn oil) and brought to the final volume appropriate for each concentration (concentrations of 10, 35 and
100 mg/mL) and kept under magnetic stirrer at room temperature prior to use and until the time of dosing of the last animal.
The formulations were prepared daily and the concentrations were calculated and expressed in terms of test item as supplied.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Prior to commencement of treatment, analysis was performed to confirm that the proposed formulation procedure was acceptable (content check and homogeneity). Results of the analyses were within the limits of acceptance.
The stability was found to be 24 hours at room temperature in the concentration range of 10 to 100 mg/mL.
Samples of the formulations prepared on Week 1 and last Week were also analysed to check the concentration and homogeneity. Results of the analyses were within the limits of acceptance.
Chemical analysis was carried out by the Analytical Chemistry Department at RTC according to a validated method (RTC Study No. 90820), in the range from 1 to 200 mg/mL. The software used for this activity was the Empower® Pro build No. 2154.

Duration of treatment / exposure:

Males
Animals were dosed once a day, 7 days a week, for 2 consecutive weeks prior to pairing and thereafter through the day before necropsy.

Dose volumes were adjusted once per week for each animal according to the last recorded body weight.

Females
Animals were dosed once a day, 7 days a week, for 2 consecutive weeks prior to pairing and thereafter during pairing, post coitum and post partum periods until Day 3 post partum (the day before sacrifice).

Dose volumes were adjusted once per week for each animal according to the last recorded body weight.
During the post coitum period, dose volumes were calculated according to individual body weight on Days 0, 7, 14 and 20 post coitum and on Day 1 post partum. Thereafter individual dose volumes remained constant.

Frequency of treatment:

once a day

Dose / conc.:

50 mg/kg bw/day (nominal)

Dose / conc.:

175 mg/kg bw/day (nominal)

Dose / conc.:

500 mg/kg bw/day (nominal)

No. of animals per sex per dose:

3 groups comprised 10 male and 10 female rats received the test item at the dose levels of 50, 175 and 500 mg/kg/day. A similary constituted group of
animals received the vehicle alone (corn oil) and acted as control.

Control animals:

yes

Details on study design:

The oral route was selected as it is a possible route of exposure of the test item in man.
Dose levels of 50, 175 and 500 mg/kg/day were selected by the Sponsor based on information from previous non GLP compliant studies (RTC Study nos.: 90830EXT and 90840EXT).

Positive control:

no

Observations and examinations performed and frequency:

Mortality

Throughout the study, all animals were checked early in each working day in the morning and in the afternoon. At weekends and Public Holidays a similar procedure was followed except that the final check was carried out at approximately mid-day.

Clinical signs

Once before commencement of treatment and at least once daily during the study, each animal was observed and any clinical signs were recorded. Observations were performed approximately at the same time interval each day, the interval was selected taking into consideration the presence of post-dose reactions.

Clinical observations (Functional Observation Battery Tests)

Once before commencement of treatment and once a week thereafter, each animal was given a detailed clinical examination.
Each animal was removed from the home cage and observed in an open arena.
The tests included observation of changes in gait and posture, reactivity to handling, presence of clonic or tonic movements, stereotypies or bizarre behaviour and effects on the autonomic nervous system (e.g. lachrymation, piloerection, pupil size, unusual respiratory pattern).
All observations were recorded for individual animals.

Animals were examined in an open arena for a minimum of three minutes.

Grip strength and sensory reactivity to stimuli

Once during the study, towards the end of treatment, 5 males and 5 females were randomly selected from each group for evaluation of sensory reactivity to stimuli of different modalities (e.g. auditory, visual and proprioceptive stimuli); an assessment of grip strength was also performed. For males the tests were performed on Day 29 of the study and for females on Day 3 post partum.

Motor activity assessment (MA)

Once during the study, towards the end of treatment, 5 males and 5 females were randomly selected from each group and the motor activity was measured (at least 5 minutes) by an automated activity recording device. Measurements were performed using a computer generated random order. For males the tests were performed on Day 29 of the study and for females on Day 3 post partum.

Body weight

Males were weighed on the day of allocation to treatment groups, on the day of treatment commencement, weekly thereafter and at termination.

Females were weighed on the day of allocation to treatment groups, on the day of treatment commencement, weekly thereafter until pairing and on Days 0, 7, 14 and 20 post coitum. Dams were also weighed on Days 1 and 4 post partum.


Food consumption

The weight of food consumed by each cage of males and females was recorded weekly, where possible, during the pre-mating period following allocation. Individual food consumption for the females was measured on Days 7, 14 and 20 post coitum starting from Day 0 post coitum and on Day 4 post partum starting from Day 1 post partum

Clinical pathology investigations

As a part of the sacrificial procedure, samples of blood were withdrawn under isofluorane anaesthesia from the abdominal vena cava from 5 males and 5 females (females with viable litters) randomly selected from each group, under condition of food deprivation.
The blood samples collected were divided into tubes as follows:

EDTA anticoagulant: for haematological investigations
Heparin anticoagulant : for biochemical tests
Citrate anticoagulant : for coagulation tests


The measurements performed on blood samples are listed below:

Haematology

Haematocrit
Haemoglobin
Red blood cell count
Reticulocyte count
Mean red blood cell volume
Mean corpuscular haemoglobin
Mean corpuscular haemoglobin concentration
White blood cell count
Differential leucocyte count
- Neutrophils
- Lymphocytes
- Eosinophils
- Basophils
- Monocytes
- Large unstained cells
Platelets

Coagulation tests

Prothrombin time



Clinical chemistry

Alkaline phosphatase
Alanine aminotransferase
Aspartate aminotransferase
Gamma-glutamyltransferase
Urea
Creatinine
Glucose
Triglycerides
Bile acids
Phosphorus
Total bilirubin
Total cholesterol
Total protein
Albumin
Globulin
A/G Ratio
Sodium
Potassium
Calcium
Chloride

Sacrifice and pathology:

Parental animals were killed by exsanguination under isofluorane anaesthesia

Parental males:
Males were sacrificed after completion of the mating period after 33 days of treatment.

Parental females:
The females with live pups were killed on Day 4 post partum

Necropsy

The clinical history of the males and females of the parental generation was studied and a detailed post mortem examination was conducted (including examination of the external surface and orifices).
Changes were noted, the requisite organs weighed and the required tissue samples preserved in fixative and processed for histopathological examination

Females:
All females were examined also for the following:

a) external and internal abnormalities;
b) number of visible implantation sites (pregnant animals);
c) number of corpora lutea (pregnant animals).

Organ weights

From all animals completing the scheduled test period, the organs were dissected free of fat and weighed.
The ratios of organ weight to body weight were calculated for each animal.

Tissues fixed and preserved

Samples of all the tissues were fixed and preserved in 10% neutral buffered formalin (except testes and epididymides which were fixed in modified Davidson's fluid and preserved in 70% ethyl alcohol).


Histopathological examination

After dehydration and embedding in paraffin wax, sections of the tissues were cut at 5 micrometer thickness and stained with haematoxylin and eosin.

In addition, the testes and epididymides were cut at 2-3 micrometer thickness and stained with Periodic Acid Schiff (PAS). The morphological evaluation of the seminiferous epithelium (staging of spermatogenic cycle) was performed.

The examination was restricted as detailed below:

a) Tissues specified in section 4.5.6 from 5 males and 5 females randomly selected (animals evaluated for clinical pathology) in the control and high dose groups killed at term.
b) All abnormalities in all groups

Statistics:

Standard deviations were calculated as appropriate. For continuous variables the significance of the differences amongst group means was assessed by Dunnett’s test or a modified t test, depending on the homogeneity of data.
The non-parametric Kruskal-Wallis analysis of variance was used for the other parameters. Intergroup differences between the control and treated groups were assessed by the non-parametric version of the Williams test.
The mean values, standard deviations and statistical analysis were calculated from actual values in the computer without rounding off.

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Details on results:

Mortality and fate of females

No mortality occurred throughout the study.
All females proved to be pregnant.
The number of females with live pups on Day 4 post partum was 10 both in the control and in all treated groups.

Clinical signs and clinical observations (Functional Observation Battery Tests)

No relevant clinical signs were observed throughout the study in all treated animals of both sexes.

Neurotoxicity assessment (removal of animals from the home cage and open arena)
Observation of animals at removal from the cage and in an open arena (neurotoxicity assessment) did not reveal changes attributable to the test item.

Body weight and body weight gain

No relevant differences in body weights were recorded in animals of both sexes compared to the control group, throughout the study.

Food consumption

Food consumption was, in general, comparable between control and treated groups.

Motor activity and sensory reaction to stimuli

No relevant differences were noted in all parameters investigated between control and treated groups.

Haematology

No changes of toxicological significance were recorded.
No significant change was recorded in the coagulation test.

Clinical chemistry

The alteration (decrease in cholesterol level) noted in males receiving 500 mg/kg/day could not be conclusively attributed to treatment since it was observed in only one sex.

Terminal body weight and organ weights

Terminal body weight was unaffected by treatment in both sexes.
Changes noted in the absolute and relative organ weights were of low magnitude and no histological findings were observed at microscopic examination, therefore they were considered of no toxicological relevance.

Macroscopic observations

No treatment-related changes were noted.

Microscopic observations

No treatment-related changes were noted.
In addition seminiferous tubules were evaluated with respect to their stage in the spermatogenic cycle and no alterations were noted.

Key result

Dose descriptor:

NOAEL

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Critical effects observed:

no

Conclusions:

On the basis of the results obtained in this study, 500 mg/kg/day could be considered the NOAEL (No Observed Adverse Effect Level) for animals of both sexes.

Executive summary:

Study design

 

The toxic effects on rats of both sexes after repeated oral dosing with Benzyl methacrylate, as well as on effects of the test item on male and female reproductive performance, such as gonadal function, conception, parturition and early lactation of the offspring were investigated.

The vehicle was corn oil. All doses were administered at a constant volume of 5 mL/kg body weight.

 

Group Number	Treatment (mg/kg/day)	Number of animals
1 2 3 4	0 50 175 500	10M+10F 10M+10F 10M+10F 10M+10F

 

Males were treated for 2 weeks prior to pairing and during pairing with females until the day before necropsy, for a total of 33 days.

Females were treated for 2 weeks prior to pairing, during pairing and throughout the gestation and lactation periods until Day 3post partum.

The following investigations were performed in all groups: body weight, clinical signs (including neurotoxicity assessment, motor activity and sensory reaction to stimuli), food consumption, clinical pathology investigations (haematology and clinical chemistry), macroscopic observations, organ weights and histopathological examination.

The histopathological examination was performed only on control and high dose groups (five animals/sex/group selected randomly). It included identification of the stages of the spermatogenic cycle in five males.

 

 Mortality

 

No mortality occurred throughout the study.

Clinical signsand clinical observations (Functional ObservationBatteryTests)

 

No relevant clinical signs were observed throughout the study in all treated animals of both sexes.

Neurotoxicity assessment (removal of animals from the home cage and open arena)

Observation of animals at removal from the cage and in an open arena (neurotoxicity assessment) did not reveal changes attributable to the test item.

 

Body weight and body weight gain

 

No relevant differences in body weights were recorded in animals of both sexes compared to the control group, throughout the study.

 

Food consumption

 

Food consumption was, in general, comparable between control and treated groups.

 

Motor activity and sensory reaction to stimuli

 

No relevant differences were noted in all parameters investigated between control and treated groups.

 

 Haematology

 

No changes of toxicological significance were recorded.

No significant change was recorded in the coagulation test.

 

Clinical chemistry

 

The alteration (decrease in cholesterol level) noted in males receiving 500 mg/kg/day could not be conclusively attributed to treatment since it was observed in only one sex.

 

Terminal body weight and organ weights

 

Terminal body weight was unaffected by treatment in both sexes.

Changes noted in the absolute and relative organ weights were of low magnitude and no histological findings were observed at microscopic examination, therefore they were considered of no toxicological relevance.

 

Macroscopic observations

 

No treatment-related changes were noted.

 

Microscopic observations

 

No treatment-related changes were noted.

In addition seminiferous tubules were evaluated with respect to their stage in the spermatogenic cycle and no alterations were noted.

 

 Conclusions

 

On the basis of the results obtained in this study, 500 mg/kg/day could be considered the NOAEL (No Observed Adverse Effect Level) for animals of both sexes.

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:

chronic toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Read across to the alcohol metabolite:

According to RAAF 2019, the analogue read-across approach, Scenario 1: “read-across based on (bio)transformation to common compound(s)” has been identified as appropriate in order to fulfill the data gap.

Thus, the information requirement (according to REACH Regulation Annex IX) is covered with read across to the methacrylic metabolites.

For detailed information and justification please refer to the attached Read across Justification Document: “Read across assessment according to ECHA’s Read Across Assessment Framework (RAAF)”.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 451

Deviations:

yes

Remarks:

no data on hematology, clinical chemistry or urinalysis

Dose / conc.:

100 mg/kg bw/day (actual dose received)

Dose / conc.:

200 mg/kg bw/day (actual dose received)

Control animals:

yes, concurrent vehicle

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Key result

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Critical effects observed:

not specified

Executive summary:

Read-across to the alcohol metabolite Benzyl alcohol CAS: 100-51-6:

cited from the report:

Body Weights and Clinical Signs

Mean body weights of dosed and vehicle control male and female rats were generally comparable throughout the studies (Table 8 and Figure 3). No compound-related clinical signs were observed. In the third month of the studies in rats, swelling in the cervical region, pink eyes, and a red exudate around the eyes were observed in rats from the vehicle control and both dosed groups. The clinical signs are characteristic of sialodacryoadenitis. This was confirmed by positive titers to rat coronavirus in sentinel animals.

Survival Pathology and

Survival

Estimates of the probabilities of survival for male and female rats administered benzyl alcohol at the doses used in these studies and for vehicle controls are shown in Table 9 and in the Kaplan and Meier curves in Figure 4. The survival of the low dose group of female rats was significantly lower than that of the vehicle controls between weeks 71 and 103; the survival of the high dose group was significantly lower than that of the vehicle controls after week 50.

 

Pathology and Statistical Analyses of Results

Summaries of the incidences of neoplasms and nonneoplastic lesions, individual animal tumor diagnoses, statistical analyses of primary tumors that occurred with an incidence of at least 5% in at least one animal group, and historical control incidences for the neoplasms mentioned in this section are presented in Appendixes A and B for male and female rats, respectively.

 

Eye:

Cataracts and retinal atrophy were observed at increased incidences in high dose rats (cataracts--male: vehicle control, 2/50;low dose, 3/50;high dose, 23/50;female:2/50; 2/50;16/50; retinal atrophy--male: 1/50; 3/50; 24/50; female 1/50;3/50;20150).Records received after study termination indicated that the high dose animals were housed on the top two rows of cages except for the last 10weeks of the studies, when cage rotation procedures were implemented. Thus, exposure to fluorescent light is the probable cause of the eye lesions.

 

Forestomach:

Epithelial hyperplasia was seen in four high dose male rats. A squamous cell papilloma was seen in 1/19 low dose and 1/50 high dose male rats.

 

Lung:

Hemorrhage and foreign material in the respiratory tract were seen at increased incidences in dosed rats that died before the terminal kill. In male rats, there were dose-related increases in acute inflammation in the nasal tract, hemorrhage in the larynx, and edema, hemorrhage, and foreign material in the lungs. The incidences of hemorrhage and foreign material in the lungs also increased in female rats.

 

Anterior Pituitary Gland:

Adenomas and adenomas or carcinomas (combined) in female rats occurred with negative trends; the incidences in the high dose group were lower than those in the vehicle controls (Table 10).

For read across purposes according to ECHA's RAAF (2019), this study is applicable with a high level of confidence.

Reference 3

Endpoint:

chronic toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Read across to the alcohol metabolite:

According to RAAF 2019, the analogue read-across approach, Scenario 1: “read-across based on (bio)transformation to common compound(s)” has been identified as appropriate in order to fulfill the data gap.

Thus, the information requirement (according to REACH Regulation Annex IX) is covered with read across to the methacrylic metabolites.

For detailed information and justification please refer to the attached Read across Justification Document: “Read across assessment according to ECHA’s Read Across Assessment Framework (RAAF)”.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 451

Deviations:

yes

Remarks:

no data on hematology, clinical chemistry or urinalysis

Dose / conc.:

200 mg/kg bw/day (actual dose received)

Dose / conc.:

400 mg/kg bw/day (actual dose received)

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

no effects observed

Key result

Dose descriptor:

NOAEL

Effect level:

200 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Critical effects observed:

not specified

Executive summary:

Read-across to the alcohol metabolite Benzyl alcohol CAS: 100-51-6:

cited from the report:

Body Weights and Clinical Signs

 

Mean body weights of dosed and vehicle control were generally comparable throughout the studies (Table 13 and Figure 5). No clinical signs were associated with chemical administration in male or female mice. During week 80 of the studies, the male and female mice were mistakenly dosed with 375 and 750 mg/kg a-methyl-benzyl alcohol for 4 days, instead of with 100 and 200 mg/kg benzyl alcohol. No apparent adverse effect occurred.

For read across purposes according to ECHA's RAAF (2019), this study is applicable with a high level of confidence.

Reference 4

Endpoint:

sub-chronic toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Read across to the alcohol metabolite:

According to RAAF 2019, the analogue read-across approach, Scenario 1: “read-across based on (bio)transformation to common compound(s)” has been identified as appropriate in order to fulfill the data gap.

Thus, the information requirement (according to REACH Regulation Annex IX) is covered with read across to the methacrylic metabolites.

For detailed information and justification please refer to the attached Read across Justification Document: “Read across assessment according to ECHA’s Read Across Assessment Framework (RAAF)”.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

no data on hematology, clinical chemistry or urinalysis

Dose / conc.:

50 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

200 mg/kg bw/day (nominal)

Dose / conc.:

400 mg/kg bw/day (nominal)

Dose / conc.:

800 mg/kg bw/day (nominal)

Control animals:

yes, concurrent vehicle

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

cited from the report: High dose male and female mice exhibited staggering after dosing during the first and second week of the studies.

Mortality:

mortality observed, treatment-related

Description (incidence):

cited for the report: Deaths were observed in most dose groups, but none occured in vehicle controls. Four male and six female mice died after being dosed; all but one of the deaths were described as being related to the gavage procedures.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

cited from the report: The final mean body weight of female mice that received 400 or 800 mg/kg benzyl alcohol were 5% or 8% lower than taht of the vehicle control.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

cited from the report: No compound-related histopathologic effects were observed. Chronic intestinal pneumonia, consistent with a Sendai infection, was seen in all groups of mice.

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Key result

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

mortality

Remarks on result:

other: Read-across to the alcohol metabolite Benzyl alcohol CAS: 100-51-6.

Key result

Critical effects observed:

not specified

		Mean Body weight (grams)
Dose (mg/kg)	Survival(a)	Initial (b)	Final	Change(c)	Final weight relative to vehicle controls (percent)
Male
0	10/10	27.8±0.6	33.7±0.5	+5.9±0.7
50	10/10	27.9±0.6	33.2±0.8	+4.3±1.1	98.5
100	10/10	27.9±0.3	34.1±0.9	+6.2±0.8	101.2
200	9/10	27.4±0.5	33.8±1.1	+6.4±1.1	100.3
400	9/10	27.8±0.9	32.1±0.8	+4.3±1.1	95.3
800	8/10	27.3±0.6	32.0±0.8	+4.9±1.2	95.0
Female
0	10/10	21.0±0.2	25.1±0.4	+4.1±0.4
50	9/10	20.6±0.3	25.4±0.4	+4.8±0.6	101.2
100	8/10	20.7±0.2	25.9±0.3	+5.2±0.6	103.2
200	10/10	20.9±0.2	23.9±0.2	+3.0±0.3	95.2
400	9/10	20.7±0.3	23.8±0.3	+3.0±0.4	94.8
800	8/10	20.9±0.6	23.0±0.5	+2.1±0.4	91.6

 

(a) Number surviving/number initially in the group. One high dose female dies during week 1; all other deaths were related to the gavage procedures.

(b) Initial group mean body weight ±standard error of the mean. Subsequent calculations are based on animals surviving to the end of the study.

(c) Mean body weight change of the survivors ± standard error of the mean

Executive summary:

Read-across to the alcohol metabolite Benzyl alcohol CAS: 100-51-6:

cited from the report:

Deaths were observed in most dose groups, but none occurred in vehicle controls (Table 12). Four male and six female mice died after being dosed; all but one of the deaths were described as being related to the gavage procedures. The final mean body weights of female mice that re- ceived 400 or 800 mg/kg benzyl alcohol were 5% or 8% lower than that of the vehicle controls. High dose male and female mice exhibited stag- gering after dosing during the first and second weeks of the studies. No compound-related histopathologic effects were observed. Chronic interstitial pneumonia, consistent with a Sendai infection, was seen in all groups of mice.

For read across purposes according to ECHA's RAAF (2019), this study is applicable with a high level of confidence.

Reference 5

Endpoint:

sub-chronic toxicity: oral

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Justification for type of information:

Read across to the alcohol metabolite:

According to RAAF 2019, the analogue read-across approach, Scenario 1: “read-across based on (bio)transformation to common compound(s)” has been identified as appropriate in order to fulfill the data gap.

Thus, the information requirement (according to REACH Regulation Annex IX) is covered with read across to the methacrylic metabolites.

For detailed information and justification please refer to the attached Read across Justification Document: “Read across assessment according to ECHA’s Read Across Assessment Framework (RAAF)”.

Reason / purpose for cross-reference:

read-across source

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

no data on hematology, clinical chemistry or urinalysis

Species:

rat

Dose / conc.:

50 mg/kg bw/day (nominal)

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

200 mg/kg bw/day (nominal)

Dose / conc.:

400 mg/kg bw/day (nominal)

Dose / conc.:

800 mg/kg bw/day (nominal)

Control animals:

yes, concurrent vehicle

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

cited from the report: After dosing, rats of each sex in the 800 mg/kg group exhibited signs of neurotoxicity, including staggering, labored breathing, and lethargy.

Mortality:

mortality observed, treatment-related

Description (incidence):

cited for the report: 8/10 male rats dosed with 800 mg/kg benzyl alcohol and 1 in the 200 mg/kg group died after dosing; 1 vehicle control female rat, 1 in 400 mg/kg group and 2 in the 800 mg/kg group died after being dosed. Five of these deaths were described being related to gavage procedures (four males in the 800 mg/kg group and 1 female in the 800 mg/kg group).

Body weight and weight changes:

no effects observed

Description (incidence and severity):

cited from the report: The final mean body weight of rats that received 800 mg/kg was 7% lower than the vehicle controls for males and 5% lower of females.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

cited from the report: Blood around the nose and mouth was observed in 5/10 males after 8 weeks of chemical administation with 800 mg/kg benzyl alcohol.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

cited from the report: Compound-related histopathologic effects observed at 800 mg/kg but not at lower doses included necrosis of the denate gyrus of the hippocampus in 9/9 males and 7/7 females; skeletal muscle necrosis in 5/10 males; Tymic congestion, hemorrhage, and atrophy in 8/10 males: and nephrosis in the kidney of 6/9 males; The renal lesions were not chemial specific and were similar to those seen in age-related spontaneous renal disease, consisting of degeneration and regeneration of tubular epithelium.

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Key result

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

clinical signs

histopathology: non-neoplastic

mortality

Remarks on result:

other: Read-across to the alcohol metabolite benzyl alcohol CAS: 100-51-6

Key result

Critical effects observed:

not specified

		Mean Body weight (grams)
Dose (mg/kg)	Survival(a)	Initial(b)	Final	Change(c)	Final weight relative to vehicle controls (percent)
Male
0	10/10	146±2	311±5	+165±6
50	10/10	146±3	307±13	+161±14	99
100	10/10	149±2	326±10	+177±10	105
200	9/10	147±2	327±12	+181±13	105
400	10/10	143±2	317±5	+174±6	102
800	(d)2/10	151±2	288±4	+138±1	93
Female
0	9/10	116±1	190±8	+73±8
50	10/10	115±1	186±2	+71±2	98
100	10/10	113±1	184±3	+71±3	97
200	10/10	114±1	177±3	+63±3	93
400	9/10	114±1	172±2	+58±2	91
800	(e)8/10	114±1	180±4	+65±4	95

(a) Number surviving/number initially in the group; all deaths except those in the high dose groups were judged to be accidental.

(b) Initial group mean body weight ±standard error of the mean. Subsequent calculations are based on animals surviving to the end of the study.

(c) Mean body weight change of the survivors ± standard error of the mean

(d) Week of death: 7,8,8,8,8,8,8,8; four of the deaths were judged to be gavage related.

(e) One death during week 10 judged to be related to the gavage procedures; one additional death occurred between final weighing and terminal kill.

Executive summary:

Read-across to the alcohol metabolite Benzyl alcohol CAS: 100-51-6:

cited from the report:

Eight of 10 male rats dosed with 800 mg/kg benzyl alcohol and 1 in the 200 mg/kg group died after being dosed;1 vehicle control female rat, 1 in the 400 mg/kg group, and 2 in the 800 mg/kg group died after being dosed (Table 7). Five of these deaths were described as being related to the gavage procedures. After dosing, rats of each sex in the 800 mg/kg group exhibited signs of neurotoxicity, including staggering, labored breathing, and lethargy. Blood around the nose and mouth was observed in 5/10 males after 8 weeks of chemical administration with 800mg/kg benzyl alcohol. The final mean body weight of rats that received 800 mg/kg was 7% lower than that of the vehicle controls for males and 5 % lower for females. Compound-related histopathologic effects observed at 800 mg/kg but not at lower doses included necrosis of the dentate gyrus of the hippocampus in 9/9 males and7/7 females; skeletal muscle necrosis in 5/10 males; thymic congestion, hemorrhage, and atrophy in 8/10 males; and nephrosis in the kidney of 6/9 males. The renal lesions were not chemical specific and were similar to those seen in age-related spontaneous renal disease, consisting of degeneration and regeneration of the tubular epithelium.

For read across purposes according to ECHA's RAAF (2019), this study is applicable with a high level of confidence.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

500 mg/kg bw/day

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In an OECD TG 422 GLP study, both potential repeated dose toxicity and potential reproduction/ developmental toxicity of BNMA in Sprague Dawley rats was evaluated. BNMA was administered orally, by gavage, at the dosages of 50, 175 and 500 mg/kg/day. A further group received the vehicle, corn oil, under the same experimental conditions and acted as control group.

The treatment schedule included 2 weeks before pairing, during pairing, post coitum and postpartum periods up to Day 3 postpartum for females (day before necropsy). The males were dosed 2 weeks before pairing until the day before necropsy. Animals were administered for approximately 5 and 6 weeks for males and females, respectively.

The parental animals were monitored for daily clinical signs, weekly neurotoxicity assessment, body weight, food consumption and clinical pathology investigations. The dams were allowed to give birth and rear their offspring until Day 4 postpartum.

Regarding the analysed endpoints (mortality, fate of females, clinical signs, clinical observations, body weight (gain), food consumption, motor activity and sensory reaction to stimuli, haematology, clinical chemistry, terminal body weight and organ weights, macroscopic and microscopic findings), the results were comparable between the control and treated animals. Based on these results, the NOAEL (No Observed Adverse Effect Level) for both general toxicity and reproduction/developmental toxicity was determined to 500 mg/kg/day for males and females. 

The absence of systemic effects after repeated exposure, is supported by experimental results with the primary metabolites, MAA and Benzyl alcohol.

Due to the high corrosive potential of Methacrylic acid, the information on repeated dose toxicity is derived from a chronic drinking water study using Methyl methacrylate.

In a pre-guideline 2-year chronic drinking water study with 25 male and female rats administered 6, 60 and 2,000 ppm MMA no adverse effects were observed. The depression of the body weight by approx. 10% in female rats of the highest dose group did not continue beyond the first weeks of treatment. In female rats of the top dose group, the relative kidney weight was slightly increased (control 0.0082 ±0.0019 vs. 2000 ppm 0.0094 ± 0.0011). The histopathologic examination of the kidney revealed no abnormalities or lesions. The NOAEC was reported as 2,000 ppm (corresponding to 164 and 124 mg/kg bw/d, respectively) in male and female rats.

 

Benzyl alcohol

In an oral chronic NTP-study which consists of two preliminary dose range finder studies (16 d- and 90d-study), the chronic effects of BA were examined. The study was conducted in mice and rats. Both 103-weeks studies were considered as key studies on repeated dose toxicity for the alcohol metabolite. The 90-d studies were only supportive as they were conducted as dose range finder for the 103-week studies.

In the chronic study, 50 male and female rats were administered 200 and 400 mg/kg BA for 103 weeks. The results were compared with effects seen in the vehicle control group which received corn oil. There were no adverse effects observed in any of the treated groups. Consequently, the NOAEL was 400 mg/kg bw/d.

In an oral chronic NTP-study, 50 male and female mice were administered 0, 100 and 200 mg/kg BA for 103 weeks. In the study report, no treatment-related effects were observed. Therefore, the NOAL was 200 mg/kg bw/d.

In a supportive oral 13-week study conducted by NTP using 10 rats/sex/ dose, the systemic effects of BA were examined to derive the optimal dosages for a 103-week study. The animals were dosed with 0/ 50/ 100/ 200/ 400 and 800 mg/kg BA. Treatment-related deaths were reported in the 800 mg/kg group. Furthermore, signs of neurotoxicity (including lethargy, staggering and laboured breathing) were observed at the highest dose group. Blood around mouth and nose was reported in animals of the top dose group. The body weight was slightly (- 7 or 5% decreased in high dose male and females, respectively) affected by the treatment. In the histopathologic examination of vehicle control and high dose rats, a necrosis of the dentate gyrus of the hippocampus, skeletal muscle necrosis in males and thymic congestion, haemorrhages and atrophy in males were observed. Therefore, the NOAEL was 400 mg/kg bw/d.

The same study was performed in mice as dose range finder for the 103-weeks study. There was only one treatment-related death reported. The body weight was slightly (- 5 or 9% at high dose males and females, respectively and -5% at 2^ndhighest dose males and females) affected by the BA administration. No treatment-related histopathologic changes were reported. Therefore, the NOAEL was 200 mg/kg bw/d.

 

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
OECD guideline 422 study, no deviations, GLP

Justification for classification or non-classification

Based on the available data, BNMA does not need to be classified for toxicity to reproduction, developmental toxicity and teratogenicityaccording to the criteria given in regulation (EC) 1272/2008. Thus, no labelling is required.