Methacrylic anhydride

Endpoint summary

Description of key information

No data available for MAAH.

Read across data from methacrylic acid, MAA (hydrolysis product and primary metabolite) and methyl methacrylate, MMA (metabolite donor substance; read across justification see attached document):

oral

2 yr drinking water, rats, MMA: NOAEL 2000 ppm = 124/ 164 mg/kg bw/d in males and females

inhalation

90 d/ OECD 413, rats, MAA: NOAEC 100 ppm (male/female) (= 352 mg/m³ for local effects and unspecific systemic effects to body weight)
2 yr, NTP protocol, rats, MMA: NOAEC 350 ppm (male/female) (= 1232 mg/m³ for systemic effects in target organs other than body weight effects due to reduced food consumption)

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Qualifier:

equivalent or similar to guideline

Guideline:

other: not known

Principles of method if other than guideline:

Chronic, repeated dose study with exposure via drinking water

GLP compliance:

no

Limit test:

no

Specific details on test material used for the study:

source: Rohm & Haas company, Philadelphia
stabilized with 10 ppm monomethylether of t-butylhydroquinone

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: "young" (unspecified)
The  animals were individually housed and provided food (finely ground Purina Dog Chow Kibbled Meal; questionable information in the publication) ad libitum
- rats were individually caged and weighed once a week

Route of administration:

oral: drinking water

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

The rats were individually caged and weighed once a week. The diet consisted of finely ground Purina Dog Chow Kibbled Meal consumed ad libitum. Fluid consumption values were determined over a 3-day period at the end of 1 and 4 weeks,
monthly through 6 months, and on even months thereafter. Food consumptions were measuered over 3-day periods at the same intervals.
The low and medium concentrations in the water were selected with the expectation that the diet equivalents would approximate 10 and 100 ppm. The high concentration was selected following preliminary tests that indicated
that this level would significantly depress fluid consumption.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

polarographic analysis of monomer content

Duration of treatment / exposure:

104 weeks (2 years)

Frequency of treatment:

Daily, ad libitum

Dose / conc.:

6 ppm

Remarks:

raised after 5 months to 7 ppm

Dose / conc.:

60 ppm

Remarks:

raised after 5 months to 70 ppm

Dose / conc.:

2 000 ppm

Dose / conc.:

12 other: ppm (on the basis of fluid and food consumption observations)

Remarks:

corresponding to roughly 0.6 mg/kg/bw (based on a conversion factor of 20 (Derelanko, M.J.,
2000)corresponding to roughly 0.6, 6 and 165 mg/kg/bw (based on a conversion factor of 20
(Derelanko, M.J., 2000)

Dose / conc.:

120 other: ppm (on the basis of fluid and food consumption observations)

Remarks:

corresponding to roughly 6 mg/kg/bw (based on a conversion factor of 20 (Derelanko, M.J., 2000)

Dose / conc.:

3 000 other: ppm (on the basis of fluid and food consumption observations)

Remarks:

corresponding to roughly 165 mg/kg/bw (based on a conversion factor of 20 (Derelanko, M.J., 2000)

No. of animals per sex per dose:

25

Control animals:

yes, concurrent no treatment

Details on study design:

Twenty-five male and female albino (Wistar) rats were administered 6, 60 or 2000 ppm of methyl methacrylate in the drinking water. The concentrations of the low- and mid-dose groups were increased to 7 and 70 ppm at the beginning of the fifth month of the study. The animals were individually housed and provided food ad libitum.  
Prior to the start of the study, it was apparent that methyl methacrylate was volatilizing at the tip of the water bottles. A special design was employed to reduce the volatilization and measurements showed that the methyl methacrylate concentrations remained within 15% of nominal for 72 hours.
The low and medium concentrations in the water were selected with the expectation that the diet equivalents would approximate 10 and 100 ppm. The high concentration was selected following preliminary tests that indicated that this level would significantly depress fluid consumption.

Observations and examinations performed and frequency:

Body weights were measured prior to study initiation, at weeks 1, 3, 6, 13, 26, 52, 78 and 104. Food and water consumption was measured over a three day period at the end of one and four weeks, monthly through month six and during even months thereafter. Hematological measurements, including hematocrit, hemoglobin, total white and differential white cell counts, were obtained from five rats from each sex in each treatment level at three month intervals. Pooled urine samples were collected from five rats per sex from each treatment group every three months to evaluate urinary concentrations of reducing substances and proteins.

Sacrifice and pathology:

Semiquantitative tests for urinary concentrations of reducing substances and protein were performed on urines pooled from 5 rats/sex per group at three month intervals. At two years, survivors were sacrificed and organ to body weight measurements were made for heart, spleen, kidney, liver and testes. Tissues preserved from all animals on study included heart, lung, kidney, liver, urinary bladder, spleen, gastrointeric, skeletal muscle, bone marrow, skin, brain, thyroid, adrenal, pancreas, pituitary and gonad. Histopathology was conducted on all tissues collected except from animals in the low dose group.

Haematological findings:

no effects observed

Description (incidence and severity):

Hematologic values varied within normal ranges in ali' groups of rats throughout the study

Urinalysis findings:

no effects observed

Description (incidence and severity):

Urine concentrations of protein and reducing substances showed no trends that appeared relatable to treatment.

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

Organ to body weight ratios obtained at sacrifice of 2-year survivors differed from the controls only in significantly increased kidney ratios in female rats receiving 2000 ppm of methyl methacrylatc (controls 0.0082 ± 0.0019; treated 0.0094 ± 0.0011).

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

Histopathologic findings showed no abnormalities or lesions, in kind or incidence, not explicable on the basis of naturally occurring ones in this strain of rat at this age.

Details on results:

Body weight depression observed at 2000 ppm did not persist beyond the first few weeks of the study. Significant depression of fluid consumption was observed at 2000 ppm, although this tended to regress at the end of the study. Individual observations of depressed food consumption tended to parallel periods of depressed growth. These effects were considered as temporary non-adverse effects.
There were significantly increased kidney weight ratios for female rats at 2000 ppm. Since no substance-related effects were reported from histopathologic examinations in the kidneys, this effect is not considered as biologically relevant.

Dose descriptor:

NOAEL

Effect level:

>= 124.1 mg/kg bw/day (actual dose received)

Sex:

male

Basis for effect level:

other: based on fluid consumption and body weight (see attached document)

Dose descriptor:

NOAEL

Effect level:

>= 164 mg/kg bw/day (actual dose received)

Sex:

female

Basis for effect level:

other: based on fluid consumption and body weight (see attached document)

Dose descriptor:

NOAEL

Effect level:

>= 2 000 other: ppm nominal

Sex:

male/female

Basis for effect level:

other: corresponding to ca. 3300 ppm in the diet on the basis of fluid and food consumption observations

Critical effects observed:

not specified

Mortality:

A summary of the mortality data for methyl methacrylate is presented below.

Dose group (ppm)            Male           Female
Negative              (0)          12/25           9/25
                           6/7           7/25           7/25
          60/70          10/25           7/25
           2000          12/25          10/25

No statistical differences were noted in the mortality of the animals exposed to methyl methacrylate and those in the control group. A statistically significant decrease in body weight was observed in the first week for the female rats and in weeks one through three in the male rats administered 2000 ppm methyl methacrylate. Water consumption was reduced in the animals from the high-dose group; however, it was reported that this finding tended to regress towards the end of the study. Food consumption was not affected by the administration of methyl methacrylate in the drinking water. 

  

Hematologic values varied within normal ranges in all groups of rats throughout the study, and urine concentrations of protein and reducing substances showed no trends that appeared relatable to treatment.

Organ to body weight ratios obtained at sacrifice of 2-year survivors differed from the controls only in significantly increased kidney ratios in female rats receiving 2000 ppm of methyl methacrylate (controls 0.0082 ± 0.0019; treated 0.0094 ± 0.0011).

Histopathologic findings showed no abnormalities or lesions, in kind or incidence, not explicable on the basis of naturally occurring ones in this strain of rat at this age.

  

Diet equivalents of the test materials were calculated from the fluid and food consumption data.

In these calculations, corrections were not made for evaporation losses of the test materials from the drinking water, the orders of magnitude of which are given under methods described above (maximum 15%). Allowing for such losses, it would appear that the concentrations of test materials in the drinking water were equivalent to approximately 10, 100, and 3000 ppm in the diet.

Conclusions:

No relevant effects were observed up to the highest dose tested (2000 ppm, limited by palatability) in a 2 years study in rats by oral administration in drinking water.

Executive summary:

A two years toxicity study was performend in 1964 to study the tolerance of animals to chronic ingestion of methyl methacrylate. No relevant effects were observed after exposure of rats in drinking water up to the highest dose tested (2000 ppm, limited by palatability)..

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Reference 1

Endpoint:

chronic toxicity: inhalation

Remarks:

combined repeated dose and carcinogenicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: NTP standard protocol, cancer bioassay with limited dose range

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Remarks on MMAD:

MMAD / GSD: vapour

Analytical verification of doses or concentrations:

yes

Duration of treatment / exposure:

2 years

Frequency of treatment:

6 h / day, 5 d / wk

Remarks:

Doses / Concentrations:
0, 500, 1000 ppm for males
Basis:
other: analytically confirmed nominal concentrations

Remarks:

Doses / Concentrations:
0, 250, 500 ppm for females
Basis:
other: analytically confirmed nominal concentrations

No. of animals per sex per dose:

50

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: random (table)
- Dose selection rationale: Based on the results of several preliminary studies up to 90 d duration

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: 2/d

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at weighing

BODY WEIGHT: Yes
- Time schedule for examinations: weekly for the first 13 weeks, monthly afterwards

FOOD CONSUMPTION, FOOD EFFICIENCY and WATER CONSUMPTION: no data
HAEMATOLOGY, CLINICAL CHEMISTRY, URINALYSIS, NEUROBEHAVIOURAL EXAMINATION: No data

Sacrifice and pathology:

GROSS PATHOLOGY and HISTOPATHOLOGY: Yes

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

URT

Histopathological findings: neoplastic:

no effects observed

Description (incidence and severity):

no relevant effect in all investigated tissues

Dose descriptor:

LOAEC

Remarks:

for local effects in the URT (no NOAEC identified)

Effect level:

250 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Histopathology (Irritation)

Dose descriptor:

NOAEC

Remarks:

for systemic effects

Effect level:

500 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

other: Gross pathology, Histopathology (organ effects)

Dose descriptor:

NOAEC

Effect level:

1 000 ppm

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Gross pathology, Histopathology (organs)

Critical effects observed:

not specified

Mortality: No difference in survival between treated and untreated groups.

Histopathology:

Site / Lesion Males	Control [0 ppm]	Low. Conc. [500 ppm]	High Conc. [1000 ppm]
Nasal Cavity /            Serous inflammation            Suppurative inflammation	0/50 11/50	37/50 21/50	44/50 30/50
Olfactory sensory epithelium /            Degeneration	7/50	39/50	42/50
Lung /            Alveolar macrophages            Focal or multifocal fibrosis	6/49  6/49	20/49  6/49	16/50  5/50
Site / Lesion Females	Control [0 ppm]	Low. Conc. [250 ppm]	High Conc. [500 ppm]
Nasal Cavity /            Serous inflammation            Suppurative inflammation	4/50 7/50	17/50 12/50	32/50 12/50
Olfactory sensory epithelium /            Degeneration	2/50	39/50	44/50
Lung /            Alveolar macrophages            Focal or multifocal fibrosis	9/50 1/50	14/50  2/50	16/50  7/50

 

No histopathological findings other than local findings in the respiratory tract. Systemic histopathological effects, as for example in the brain in females particularly at 2000 ppm and above in the subchronic range finding study (Batelle, 1980), are absent in this 104 week study.

Body weight: Mean body weight gain was reduced in females at 500 ppm resulting in 6 -11% lower body weights after week 73 and in males at 1000 ppm which were 5 -10 % lower than controls after week 81.

There was no treatment-related increase in tumour incidence.

Conclusions:

The primary finding in this study was inflammation of rat nasal cavity as well as olfactory epithelial degeneration at all exposure levels in male and female rats. For local effects the LOAEC was 250 ppm in this study while a NOAEC could not be found. 
In contrast to the 90 d range finding study with histopathological changes in females at exposures of 1000 ppm and above (Battelle, 1980), no other significant histopathological changes were reported in male and female rats after 104-week exposures to MMA vapour in this study. Based on this a NOEC for systemic effects of 500 ppm is derived.

Executive summary:

In this104-week study with groups of 50 animals each, male rats were treated with MMA vapour by whole-body exposure to 500 or 1000 ppm while female rats were exposed to 250 or 500 ppm.

 

The primary finding was inflammation of rat nasal cavity as well as olfactory epithelial degeneration at all exposure levels in male and female rats. For local effects the LOAEC was 250 ppm in this study while a NOAEC could not be found. 

In contrast to the 90 d range finding study with histopathological changes in females at exposures of 1000 ppm and above (Battelle, 1980), no other significant histopathological changes were reported in male and female rats after 104-week exposures to MMA vapour in this study. Based on this a NOEC for systemic effects of 500 ppm is derived.

 

Male and female rat body weights were lower at the 1000 ppm (5-10%) and 500 ppm (6-11%) exposure levels, respectively, presumably due to reduced food consumption due to nasal irritation and damage of olfactory epithelium. While food consumption was not recorded in this study this association is confirmed by two other studies, the developmental toxicity study with MMA with reduced food consumption and reduced body weight gain at concentrations higher than 99 ppm (Solomon, 1993) and a subchronic inhalation study with methacrylic acid where there was also an association of irritative effects in the nose and reduced food consumption and reduced body weight gain (BASF, 2008). Consequently, reduced body weight gain, while clearly treatment-related - is considered to be secondary to the local effects in the nose and not the result of true systemic toxicity.

Reference 2

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age when supplied; sex: about 7 weeks, male and female
Supplier: Charles River Laboratories, Research Models and Services, Germany GmbH; Sandhofer Weg 7, 97633 Sulzfeld
During the period when the rats were not exposed they were housed singly in wire cages (type DK III, Becker & Co., Castrop-Rauxel, FRG (floor area about 800 cm²)). Underneath the cages, waste trays were fixed containing bedding material (Type Lignocel FS14 fibres,
dustfree bedding supplied by SSNIFF, Soest, Germany)
The motor activity measurements were conducted in Polycarbonate cages with wire covers from Ehret, Emmendingen, FRG (floor area about 800 cm²) and bedding.
The animals were kept in fully air-conditioned rooms in which a temperature in the range of 20 - 24°C and relative humidity in the range of 30 - 70% were ensured by means of a central air-conditioning system.
A light/dark rhythm of 12 hours was maintained.
The room was completely disinfected using a disinfector ("AUTEX", fully automatic, formalinammonia-based terminal disinfector) before the start of the study. Usually, each week the floor and the walls were cleaned with water containing about 1 % Mikroquat®.
The animals were maintained on milled mouse/rat laboratory diet “GLP”, (Provimi Kliba SA, Kaiseraugst, Basel Switzerland) and tap water ad libitum.

Route of administration:

inhalation

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

For each concentration, the test substance was supplied to the two-component atomizer of a thermostated vaporizer at a constant rate by means of the piston metering pump. The vapor was generated by spraying the substance with compressed air into a counter current of conditioned supply air (about 50% ± 20% relative humidity, 22°C ± 2°C). Thereafter it was further mixed with conditioned supply air and passed into the inhalation system.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentrations of the inhalation atmospheres in test groups 1 - 4 were analyzed by HPLC.

Duration of treatment / exposure:

90 days

Frequency of treatment:

6 hours/day, 5 days/week

Dose / conc.:

20 ppm

Remarks:

= 70 mg/m3

Dose / conc.:

40 ppm

Remarks:

= 141 mg/m³

Dose / conc.:

100 ppm

Remarks:

= 352 mg/m³

Dose / conc.:

350 ppm

Remarks:

= 1232 mg/m³

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes, sham-exposed

Details on study design:

Ten male and ten female Sprague Dawley rats per test group were whole body exposed to a vapor of the test substance on 6 hours per working day for 90 days (65 exposures). The target concentrations were 20, 40, 100 and 350 ppm (corresponding to 70, 141, 352 and 1232 mg/m3). A concurrent control group was exposed to conditioned air.

Observations and examinations performed and frequency:

The animals were examined for evident signs of toxicity or mortality twice a day (in the morning and in the late afternoon) from Mondays to Fridays and once a day (in the morning) on Saturdays, Sundays and public holidays. The clinical condition of the test animals was recorded once during the preflow period and on post-exposure observation days and at least 3 times (before, during and after exposure) on exposure days.
During exposure only a group wise examination was possible.The body weight of the animals was determined at the start of the preflow, at the start of the exposure period and then, as a rule, once a week as well as one day prior to gross necropsy. As a rule, the animals were weighed at the same time of the day.
Body weight change was calculated as the difference between body weight on the respective exposure day and body weight on the day of the first exposure. Group means were derived from the individual differences.
Food consumption was determined weekly and calculated as mean food consumption in grams per animal and day.Food efficiency (group means) was calculated based upon individual values for body weight and food consumption.
Before the start of the exposure period (day -6) the eyes of all animals, and at the end of the study (day 82) the eyes of the animals of test group 0 (control group) and test group 4 (high concentration) were examined with an ophthalmoscope (HEINE Optotechnik, Herrsching, FRG)) for any changes in the refracting media.
Functional observation battery (FOB) was carried out on the assigned animals once before the exposure period and once against the end of the exposure period.Motor activity was measured on the same day and with the same animals as FOB was performed.

Sacrifice and pathology:

In the morning, blood was taken from the retro-orbital venous plexus from fasted animals. The animals were anaesthetized using isoflurane (Isoba®, Essex GmbH Munich, Germany). The blood sampling procedure and the subsequent analysis of the blood and serum samples were carried out in a randomized sequence. For urinalysis the individual animals were transferred to metabolism cages (withdrawal of food and water) and urine was collected overnight. The urine samples were evaluated in a randomized sequence. At necropsy specimen were sampled from fasted anesthetized male animals in a randomized sequence for sperm analyses.
Hematological parameters were determined in blood with EDTA-K3 as anticoagulant using a particle counter (Advia 120 model; Bayer, Fernwald, Germany): Furthermore differential blood smears were prepared and stained according to Wright without being evaluated.
An automatic analyzer (Hitachi 917; Roche, Mannheim, Germany) was used to examine the clinicochemical parameters.
With the exception of volume, color, turbidity, sediment examination and the specific gravity, all the urine constituents were determined semi-quantitatively using test strips (Combur-9-test M, Roche, Mannheim, Germany) and a reflection photometer (Miditron M; Roche, Mannheim, Germany).
Immediately after necropsy and organ weight determination the right testis and cauda epididymis were taken from all male animals.
Sperm motility examinations were carried out in a randomized sequence. Sperm morphology and sperm head count (cauda epididymis and testis) were evaluated for the control and highest dose group, only.
The animals were killed under Narcoren anesthesia by exsanguination from the abdominal aorta and vena cava. The animals were then be necropsied and subjected to a grosspathological assessment. Animals that died intercurrently or were killed in a moribund state were necropsied and assessed by gross-pathology as quickly as possible.

Statistics:

DUNNETT, C.W. (1955): A multiple comparison procedure for comparing several treatments with a control. JASA, Vol. 50, 1096– 1121
DUNNETT, C.W. (1964). New tables for multiple comparisons with a control. Biometrics, Vol. 20, 482 –491
SIEGEL, S. (1956): Non-parametric statistics for the behavioural sciences. McGraw-Hill New York
Nijenhuis, A.; Wilf, H.S.(1978): Combinatorial Algorithms. AcademicPress New York, 32-33
Hettmansperger, T.P. ( 1984); Statistical Inference based on Ranks. John Wiley & Sons New York, 132-142
International Mathematical and Statistical Libraries, Inc., 2500 Park West Tower One, Houston, Texas 77042-3020, USA, nakl-1 -nakl-3
MILLER, R.G. (1981): Simultaneous Statistical Inference Springer-Verlag New York Inc., 165-167

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Details on results:

Subchronic vapor inhalation of the test substance led to the following treatment-related
adverse effects:
Test group 4 (350 ppm):
􀂾 Decreased body weight of the males (- 6.1% to - 12.8%) from study day 7 onward
􀂾 Decreased body weight change (gain) of the males (- 28.5% to - 64.8%) from study
day 7 onward
􀂾 Decreased food consumption in the male animals on study days 7 (- 13.5%),
14 (- 12.2%), and from study day 28 through to day 84 (from - 9.4% to - 13.7%)
􀂾 Decreased food efficiency in the male animals on study days 7, 28, 49 and 56
􀂾 Decrease of terminal body weights in both sexes
􀂾 Goblet cell hypertrophy/hyperplasia in the respiratory epithelium of the nasal cavity
(level I) of two females
Test group 1 (20 ppm), test group 2 (40 ppm) and test group 3 (100 ppm):
􀂾 No treatment-related findings

Dose descriptor:

NOAEC

Remarks:

systemic effects

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

food efficiency

Remarks on result:

other: = 352 mg/3

Dose descriptor:

NOAEC

Remarks:

local effects

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Remarks on result:

other:

Remarks:

= 352 mg/3

Dose descriptor:

LOAEC

Remarks:

systemic effects

Effect level:

350 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

food efficiency

Remarks on result:

other: = 1232 mg/m3

Dose descriptor:

LOAEC

Remarks:

local effets

Effect level:

350 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

histopathology: non-neoplastic

Remarks on result:

other: = 1232 mg/m3

Critical effects observed:

not specified

Conclusions:

In a valid guideline study, the no-observed adverse effect level (NOAEL) for both, local and systemic effects is 100 ppm for male and female rats exposed by whole body inhalation for 90 days.

Executive summary:

In a valid guideline study acc. to OECD 413 ( Subchronic inhalation toxicity: 90 day exposure of rats), methacrylic acid induced signs of general toxicity as indicated by descreased body weight, body weight gain, food consumption and transiently food efficiency in the high concentration male animals. At a concentration as high as 350 ppm (1232 mg/m³), the local irritating effect was marginal, indicated by the hypertrophy/hyperplasia of the respiratory epithelium in the nasal cavity of two female animals. Substance-related changes of the sexual organs were not noted in any of the exposed animals, nor were there any changes of sperm mobility and sperm head counts. Under the current test conditions, the no-observed adverse effect level (NOAEL) for both, local and systemic effects, in this study is 100 ppm (352 mg/m³) for male and female rats.

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:

no adverse effect observed

Dose descriptor:

NOAEC

1 232 mg/m³

Study duration:

subchronic

Species:

rat

Quality of whole database:

The study is GLP compliant and Klimisch score 1.

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Reference

Endpoint:

sub-chronic toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 413 (Subchronic Inhalation Toxicity: 90-Day Study)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age when supplied; sex: about 7 weeks, male and female
Supplier: Charles River Laboratories, Research Models and Services, Germany GmbH; Sandhofer Weg 7, 97633 Sulzfeld
During the period when the rats were not exposed they were housed singly in wire cages (type DK III, Becker & Co., Castrop-Rauxel, FRG (floor area about 800 cm²)). Underneath the cages, waste trays were fixed containing bedding material (Type Lignocel FS14 fibres,
dustfree bedding supplied by SSNIFF, Soest, Germany)
The motor activity measurements were conducted in Polycarbonate cages with wire covers from Ehret, Emmendingen, FRG (floor area about 800 cm²) and bedding.
The animals were kept in fully air-conditioned rooms in which a temperature in the range of 20 - 24°C and relative humidity in the range of 30 - 70% were ensured by means of a central air-conditioning system.
A light/dark rhythm of 12 hours was maintained.
The room was completely disinfected using a disinfector ("AUTEX", fully automatic, formalinammonia-based terminal disinfector) before the start of the study. Usually, each week the floor and the walls were cleaned with water containing about 1 % Mikroquat®.
The animals were maintained on milled mouse/rat laboratory diet “GLP”, (Provimi Kliba SA, Kaiseraugst, Basel Switzerland) and tap water ad libitum.

Route of administration:

inhalation

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

For each concentration, the test substance was supplied to the two-component atomizer of a thermostated vaporizer at a constant rate by means of the piston metering pump. The vapor was generated by spraying the substance with compressed air into a counter current of conditioned supply air (about 50% ± 20% relative humidity, 22°C ± 2°C). Thereafter it was further mixed with conditioned supply air and passed into the inhalation system.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The concentrations of the inhalation atmospheres in test groups 1 - 4 were analyzed by HPLC.

Duration of treatment / exposure:

90 days

Frequency of treatment:

6 hours/day, 5 days/week

Dose / conc.:

20 ppm

Remarks:

= 70 mg/m3

Dose / conc.:

40 ppm

Remarks:

= 141 mg/m³

Dose / conc.:

100 ppm

Remarks:

= 352 mg/m³

Dose / conc.:

350 ppm

Remarks:

= 1232 mg/m³

No. of animals per sex per dose:

10/sex/dose

Control animals:

yes, sham-exposed

Details on study design:

Ten male and ten female Sprague Dawley rats per test group were whole body exposed to a vapor of the test substance on 6 hours per working day for 90 days (65 exposures). The target concentrations were 20, 40, 100 and 350 ppm (corresponding to 70, 141, 352 and 1232 mg/m3). A concurrent control group was exposed to conditioned air.

Observations and examinations performed and frequency:

The animals were examined for evident signs of toxicity or mortality twice a day (in the morning and in the late afternoon) from Mondays to Fridays and once a day (in the morning) on Saturdays, Sundays and public holidays. The clinical condition of the test animals was recorded once during the preflow period and on post-exposure observation days and at least 3 times (before, during and after exposure) on exposure days.
During exposure only a group wise examination was possible.The body weight of the animals was determined at the start of the preflow, at the start of the exposure period and then, as a rule, once a week as well as one day prior to gross necropsy. As a rule, the animals were weighed at the same time of the day.
Body weight change was calculated as the difference between body weight on the respective exposure day and body weight on the day of the first exposure. Group means were derived from the individual differences.
Food consumption was determined weekly and calculated as mean food consumption in grams per animal and day.Food efficiency (group means) was calculated based upon individual values for body weight and food consumption.
Before the start of the exposure period (day -6) the eyes of all animals, and at the end of the study (day 82) the eyes of the animals of test group 0 (control group) and test group 4 (high concentration) were examined with an ophthalmoscope (HEINE Optotechnik, Herrsching, FRG)) for any changes in the refracting media.
Functional observation battery (FOB) was carried out on the assigned animals once before the exposure period and once against the end of the exposure period.Motor activity was measured on the same day and with the same animals as FOB was performed.

Sacrifice and pathology:

In the morning, blood was taken from the retro-orbital venous plexus from fasted animals. The animals were anaesthetized using isoflurane (Isoba®, Essex GmbH Munich, Germany). The blood sampling procedure and the subsequent analysis of the blood and serum samples were carried out in a randomized sequence. For urinalysis the individual animals were transferred to metabolism cages (withdrawal of food and water) and urine was collected overnight. The urine samples were evaluated in a randomized sequence. At necropsy specimen were sampled from fasted anesthetized male animals in a randomized sequence for sperm analyses.
Hematological parameters were determined in blood with EDTA-K3 as anticoagulant using a particle counter (Advia 120 model; Bayer, Fernwald, Germany): Furthermore differential blood smears were prepared and stained according to Wright without being evaluated.
An automatic analyzer (Hitachi 917; Roche, Mannheim, Germany) was used to examine the clinicochemical parameters.
With the exception of volume, color, turbidity, sediment examination and the specific gravity, all the urine constituents were determined semi-quantitatively using test strips (Combur-9-test M, Roche, Mannheim, Germany) and a reflection photometer (Miditron M; Roche, Mannheim, Germany).
Immediately after necropsy and organ weight determination the right testis and cauda epididymis were taken from all male animals.
Sperm motility examinations were carried out in a randomized sequence. Sperm morphology and sperm head count (cauda epididymis and testis) were evaluated for the control and highest dose group, only.
The animals were killed under Narcoren anesthesia by exsanguination from the abdominal aorta and vena cava. The animals were then be necropsied and subjected to a grosspathological assessment. Animals that died intercurrently or were killed in a moribund state were necropsied and assessed by gross-pathology as quickly as possible.

Statistics:

DUNNETT, C.W. (1955): A multiple comparison procedure for comparing several treatments with a control. JASA, Vol. 50, 1096– 1121
DUNNETT, C.W. (1964). New tables for multiple comparisons with a control. Biometrics, Vol. 20, 482 –491
SIEGEL, S. (1956): Non-parametric statistics for the behavioural sciences. McGraw-Hill New York
Nijenhuis, A.; Wilf, H.S.(1978): Combinatorial Algorithms. AcademicPress New York, 32-33
Hettmansperger, T.P. ( 1984); Statistical Inference based on Ranks. John Wiley & Sons New York, 132-142
International Mathematical and Statistical Libraries, Inc., 2500 Park West Tower One, Houston, Texas 77042-3020, USA, nakl-1 -nakl-3
MILLER, R.G. (1981): Simultaneous Statistical Inference Springer-Verlag New York Inc., 165-167

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Details on results:

Subchronic vapor inhalation of the test substance led to the following treatment-related
adverse effects:
Test group 4 (350 ppm):
􀂾 Decreased body weight of the males (- 6.1% to - 12.8%) from study day 7 onward
􀂾 Decreased body weight change (gain) of the males (- 28.5% to - 64.8%) from study
day 7 onward
􀂾 Decreased food consumption in the male animals on study days 7 (- 13.5%),
14 (- 12.2%), and from study day 28 through to day 84 (from - 9.4% to - 13.7%)
􀂾 Decreased food efficiency in the male animals on study days 7, 28, 49 and 56
􀂾 Decrease of terminal body weights in both sexes
􀂾 Goblet cell hypertrophy/hyperplasia in the respiratory epithelium of the nasal cavity
(level I) of two females
Test group 1 (20 ppm), test group 2 (40 ppm) and test group 3 (100 ppm):
􀂾 No treatment-related findings

Dose descriptor:

NOAEC

Remarks:

systemic effects

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

food efficiency

Remarks on result:

other: = 352 mg/3

Dose descriptor:

NOAEC

Remarks:

local effects

Effect level:

100 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

histopathology: non-neoplastic

Remarks on result:

other:

Remarks:

= 352 mg/3

Dose descriptor:

LOAEC

Remarks:

systemic effects

Effect level:

350 ppm

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

food efficiency

Remarks on result:

other: = 1232 mg/m3

Dose descriptor:

LOAEC

Remarks:

local effets

Effect level:

350 ppm

Based on:

test mat.

Sex:

female

Basis for effect level:

histopathology: non-neoplastic

Remarks on result:

other: = 1232 mg/m3

Critical effects observed:

not specified

Conclusions:

In a valid guideline study, the no-observed adverse effect level (NOAEL) for both, local and systemic effects is 100 ppm for male and female rats exposed by whole body inhalation for 90 days.

Executive summary:

In a valid guideline study acc. to OECD 413 ( Subchronic inhalation toxicity: 90 day exposure of rats), methacrylic acid induced signs of general toxicity as indicated by descreased body weight, body weight gain, food consumption and transiently food efficiency in the high concentration male animals. At a concentration as high as 350 ppm (1232 mg/m³), the local irritating effect was marginal, indicated by the hypertrophy/hyperplasia of the respiratory epithelium in the nasal cavity of two female animals. Substance-related changes of the sexual organs were not noted in any of the exposed animals, nor were there any changes of sperm mobility and sperm head counts. Under the current test conditions, the no-observed adverse effect level (NOAEL) for both, local and systemic effects, in this study is 100 ppm (352 mg/m³) for male and female rats.

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

Dose descriptor:

NOAEC

352 mg/m³

Study duration:

subchronic

Species:

rat

Quality of whole database:

The study is GLP compliant and Klimisch score 1.

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Repeated dose dermal irritation study, histopathology of skin only, study purpose was to investigate skin reactions of dilutions

Principles of method if other than guideline:

Method: other: application on the shaved backs of mice , male ICR-mice, 8 animals/dose group
100 ul per mouse/day for a total of 9 treatment days

GLP compliance:

not specified

Limit test:

no

Species:

mouse

Strain:

other:

Sex:

male

Duration of treatment / exposure:

3 weeks

Frequency of treatment:

3 time/week

Remarks:

Doses / Concentrations:
4 % aq. sol. of MAA and 4.8 - 19.2 % aqueous solution of methacrylic acid in acetone
Basis:

No. of animals per sex per dose:

8 animals/dose group

Control animals:

other: yes (solvent)

Details on study design:

100 ul per mouse/day for a total of 9 treatment days

Clinical signs:

no effects observed

Dermal irritation:

effects observed, treatment-related

Description (incidence and severity):

see results

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Details on results:

With MAA as an aqueous solution of 4.8 % (= approx. 150 mg/kg) no skin irritation was observed after single or repeated dermal exposure up to 21 d (treatment interval 2-3 days, 9 exposures). When methacrylic acid was diluted in acetone and applied similarly, concentration-related irritation was observed. At 4.8 % in acetone, there was minimal irritation within the first 72 hours which progressed to slight after 21 d. Moderate to severe irritation was observed with 9.6 % (= approx. 300 mg/kg) and  19.3 % (= approx. 600 mg/kg) solutions with hyperplasia, hyperkeratosis, fibrosis, ulceration and necrosis. No clinical signs indicative of systemic toxicity were observed at any dose in any of the mice.

Dose descriptor:

NOAEL

Effect level:

600 mg/kg bw/day

Sex:

male

Basis for effect level:

other: (= 19.3 % / 2.24 M) Local irritation, but no clinical signs of systemic effects

Critical effects observed:

not specified

Conclusions:

Dilutions of MAA in acetone and water show mild irritation at 4.8 % in a study in mice, in which dilutions of MAA were applied for 21 d in succession, while the effects are more pronounced at 9.6 % in acetone and progress to severe irritation at 19.2 % in acetone.

Executive summary:

Dilutions of MAA in acetone and water show mild irritation at 4.8 % in a study in mice, in which dilutions of MAA were applied for 21 d in succession, while the effects are more pronounced at 9.6 % in acetone and progress to severe irritation at 19.2 % in acetone.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Additional information

There are no studies available for repeated dose toxicity of methacrylic anhydride. As methacrylic anhydride was demonstrated to hydrolyse very fast into methacrylic acid, and methacrylic acid is the hydrolysis product and primary metabolite of methacrylic anhydride, this endpoint is covered by read across to data of methacrylic acid (MAA) or methyl methacrylate (MMA), the metabolite donor substance (see attached read across justification).

ORAL

MMA: An early 2-year chronic drinking water study with 25 male and 25 female rats administered with 6, 60 and 2000 ppm MMA no adverse effect were observed other than elevated kidney weights without corresponding histopathology in female rats at 2000 ppm (Borzelleca et al., 1964). The NOAEC was reported as 2000 ppm (164 and 124 mg/kg bw/d) in female and male rats.

DERMAL

There are no relevant dermal repeated dose studies for systemic effects. For assessment purposes theoral study is used with the appropriate route-to-route extrapolation factor.

The available 3-week study (Rohm and Haas, 1986) is used as supporting information for classification and labelling purposes.

INHALATION

MMA: The US National Toxicology Program conducted a series of repeat-exposure inhalation toxicity studies of increasing duration 14 weeks and 104 weeks in male and female rats and mice. (Battelle Pacific Northwest Lab., 1980 and NTP; 1986). In the two-year study reduced mean body weights in female rats was observed at 500 ppm (2080 mg/m3) after week 73 but this was likely a consequence of the local nasal lesion and effects on smell and behaviour/appetite rather than any other systemic organ toxicity. The NOAEC for this effect was 250 ppm (1040 mg/m3) in females. After a 14-week inhalation, mice had cellular necrosis in liver and renal cortices > ca. 8.2 mg/L (2,000 ppm) and rats showed splenic follicular atrophy and bone marrow atrophy at ca. 20.8 mg/L (5,000 ppm; Battelle 1980). Malacia and gliosis of the brain in the 14 week range finder to the NTP study (Battelle, 1980) is considered being the relevant systemic effect, which was seen in 5/9 female rats exposed at 2000 ppm and 1/8 females at 1000 ppm. Therefore, the absence of this effect at 500 ppm (2028 mg/m³) in the corresponding 2-year study (NTP) is considered representing the NOAEC for chronic systemic effects of MMA.

Effects on the nasal respiratory tract were seen in studies in rats and mice in studies of 14 weeks Battelle Pacific Northwest Lab (1980a) and 104 weeks duration (NTP; 1986a). Local effects included inflammation of the nasal cavity and were observed in male and female rats at 250ppm (1040 mg/m3) and above. No compound-related effects were observed in the trachea and larynx. A NOAEC could not be established for local effects. (Considering the Reno and NTP studies were both two year inhalations studies using the same strain of rats the NOAEC for systemic effects of 250ppm in females from the NTP study takes precedence).

MAA: In an OECD 413, 90-day vapour inhalation study in Sprague Dawley rats with MAA revealed general toxicity at 350 ppm (1253 mg/m3) in male animals (BASF 2008). Local, marginal irritation of the respiratory epithelium in the nasal cavity was observed in two female animals. No changes in sexual organs or sperm mobility and sperm head counts were noted. The NOAEL was 100 ppm (358 mg/m3) for local irritation effects in male and females The NOAEL for systemic effects based upon reduced body weight gain in the presence of reduced feed intake but no other systemic effects was also 100 ppm (358 mg/m3) in male and females.

Justification for classification or non-classification

Based on the available data, no classification is proposed for chronic specific target organ toxicity (STOT repeated exposure).

The observed irritation is covered by classification as a respiratory irritant (STOT single exposure), category 3 according to CLP (1272/2008/EC) and UN GHS.