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Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

Oral 2 -generation study in rats according to OECD 416 (BASF 2009)


NOAEL systemic tox P, F1 = 400 mg/kg in absence of adverse effects


NOEL systemic tox P, F1 = 50 mg/kg due to reduced body weight gain associated with reduced food consumption, presumably due to bad palatability


NOAEL reproductive tox, all generations = 400 mg/kg in absence of adverse effects


NOAEL developmental tox, all generations = 400 mg/kg in absence of adverse effects

Link to relevant study records
Reference
Endpoint:
two-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2008-12-06 - 2009-04-28
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 416 (Two-Generation Reproduction Toxicity Study)
GLP compliance:
yes
Specific details on test material used for the study:
- Name of test substance: Methyl Methacrylate
- Batch identification: 012231eda0
- CAS-No.: 80-62-6
- Physical state/appearance: Liquid /colorless, clear
- Purity: 99.9 %
- Homogeneity: Given
- Storage conditions: Refrigerator; avoid temperatures >35°C
- Storage stability: Expiry date: 16 Jan 2009. The stability of the test substance under storage conditions over the test period was guaranteed by the manufacturer, and the manufacturer holds this responsibility.
Sex:
male/female
Details on mating procedure:
)
Duration of treatment / exposure:
until one day before sacrifice
Frequency of treatment:
once daily
Parental animals: Observations and examinations:
.
Sperm parameters (parental animals):
.
Postmortem examinations (parental animals):
SACRIFICE AND GROSS NECROPSY
All F0 and F1 parental animals were sacrificed by decapitation under Isoflurane anesthesia. The exsanguinated animals were necropsied and assessed by gross pathology; special attention was given to the reproductive organs.

HISTOPATHOLOGY / ORGAN WEIGHTS
Weight assessment was carried out on all animals sacrificed at scheduled dates. The following weights were determined: Anesthetized animals, liver, kidneys, adrenal glands, testes, epididymides, cauda epididymis, prostate, seminal vesicles including coagulation glands, ovaries, uterus, spleen, brain, pituitary gland, thyroid glands (with parathyroid glands). The following organs or tissues of the F0 and F1 generation parental animals were fixed in 4% neutral buffered formaldehyde solution or in BOUIN’s solution, respectively: Vagina, cervix uteri, uterus, ovaries (BOUIN), oviducts, left testis (BOUIN), left epididymis (BOUIN), seminal vesicles, coagulation glands, prostate, pituitary gland, adrenal glands, liver, kidneys, spleen, brain, thyroid glands (with parathyroid glands), all gross lesions. After fixation, the organs fixed in BOUIN´s solution were embedded in Paraplast. Fixation was followed by histotechnical processing, examination by light microscopy and assessment of findings.

OTHER:
- Differential Ovarian Follicle Count (DOFC) in F1 generation: From both ovaries (”ovary 1” and “ovary 2”) of F1 female animals (control and top dose), five sections were taken from the proximal and the distal part of the ovaries, respectively, at least 100 µm apart from the inner third of the ovary. All ovarian sections were prepared and evaluated. Primordial follicles and growing follicles were counted by light microscope (magnification: 100x) on each of these slides, – according to the definitions given by Plowchalk et al. (PLOWCHALK, D. R., B. J. SMITH, and D. R. MATTISON: Assessment of Toxicity to the Ovary Using Follicle Quantitation and Morphometrics. In: Methods in Toxicology, Vol. 3, Part B: Female Reproductive Toxicology (J. J. HEINDEL and R. E. CHAPIN, Editors), p. 57-68, 1993, Academic Press). To prevent multiple counting on serial slides – especially of the growing follicles – only follicles with an oocyte with visible chromatin on the slide were counted. The number of each type of follicle was recorded individually for ovary 1 and ovary 2 of every animal on any of the slide levels (level 1-10), giving in summary the incidence of each type of the follicles by using EXCEL sheets for the reporting of the results. Finally, the results of all types of follicles were summarized for all animals per group in dose groups 10 and 13. As primordial follicles continuously develop into growing follicles, the assessment of the follicles was extended to the combined incidence of primordial plus growing follicles. In general, the fifth slide of the left and right ovary was evaluated for histological findings. Whenever the diagnosis: ”no abnormalities detected” was used for the ovaries, this implicates all functional statuses of follicles, especially corpora lutea, were present. An attempt was made to correlate gross lesions with histopathological findings.
Offspring viability indices:
.
Clinical signs:
no effects observed
Description (incidence and severity):
Clincial signs of males and females except gestation and lactation period:
A male and 7 females of the high dose group showed transient salivation during major parts of the treatment period. Salivation persisted in the respective animals only for some minutes after daily
gavage (i.e. upto 15 minutes). This symptom is initially observed during study week 5.
The temporary salivation is considered to be test item-related. Form the temporary, short appearance immediately after dosing, it is likely that this finding was induced by the bad taste of the test item or lo
cal affection of the upper digestivve tract. It was clearly considered to be not an adverse toxicological finding. There were no clinical signs in low and mid-dose animals.
Clinical signs of females in females during gestation of F1 litters:
NIne out of 25 high dose females showed transient salivation during major parts of the gestation period (GD 0-16 and GD 20). There were no clinical signs in low and mid-dose females.
Clinical signs of females and offspring during lactation of F1 litters:
Seven out of 24 high dose females showed transient salivation during major parts of the lactation period (OND 0-8; PND 10; PND 14-16 and PND 18-21). The F0 animals and the low and mid-dose
females showed no clinical signs.
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Description (incidence):
There were no test item-related mortalities in any of the male and female parental animals in any of the groups. During study week 11, one high dose female was found dead, after showing hypo
thermia, salivation and labored respiration. Pathological examination revealed pleuritis and pericarditis as the cause of death, most likely secondary to a gavage error.
During lactation period, two high dose females were found dead. There were no macroscopic or histopathologic findings that could explain the death of these animals.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Mean body weights and body weight change of F0 parental males and females in the treated groups were comparable to the control group throughout the entire study. The statistically significantly increa
sed or decreased body weight change in the low-dose females during week 0-1 and weeks 4-5, in the mid-dose females during study week 1-2 and weeks 4-6 and in high dose females during weeks 4-6
was considered as spontaneous in nature.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Test group 03 (400 mg/kg bw/d)
• Statistically significantly decreased food consumption in parental males during premating weeks 5 - 10 (up to 7%)
• Statistically significantly decreased food consumption in parental females during premating weeks 1 - 3 (up to 6%), weeks 5 - 8 (up to 7%) and weeks 9 - 10 (about 6%)
• Statistically significantly decreased food consumption in parental females during gestation days 0 - 7 (about 10%)
• Statistically significantly decreased food consumption in parental females during lactation days 4 - 7 (about 7%)

Test group 02 (150 mg/kg bw/d)
• Statistically significantly decreased food consumption in parental females during premating weeks 1 - 2 (about 5%)
• Statistically significantly decreased food consumption in parental females during gestation days 0 - 7 (about 7%)

Test group 01 (50 mg/kg bw/d)
• no test substance-related adverse effects/findings
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:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
All findings were either single observations, or were similar in distribution pattern and severity in control rats compared to treatment groups. All of them were considered to be incidental and/or spo
ntaneous in origin and without any relation to treatment. Male animals and their female mating partners did not show any histopathologic findings that could explain their infertility. One male animal
revealed oligospermia and debris within the tubules of the testes and the epididymides. This could have caused the infertility in this mating pair. The female mating partner did not show any histopathologic finding that could explain the infertility.
Information on descendents: see in section mortality
Histopathological findings: neoplastic:
not examined
Other effects:
not specified
Reproductive function: oestrous cycle:
no effects observed
Description (incidence and severity):
Oestrus cycle data, generated during the last three weeks prior to mating for the F1 litter, revealed regular cycles in the females of all test groups. The mean oestrus cycle duration in the different
groups was comparable: 4.0 (control), 4.5 (low-dose), 5.7 (mid-dose) and 5.3 (high-dose).
Reproductive function: sperm measures:
no effects observed
Description (incidence and severity):
No treatment-related effects were noted for the sperm measures. The number of homogenisation resistant testicular spermatids of cauda epididymal sperm, the percentages of abnormal and normal
sperm and sperm motility data were comparable between the groups.
Reproductive performance:
no effects observed
Description (incidence and severity):
For all F0 males, copulation was confirmed. Fertility was proven for most of the F0 males. 3 control , 3 low-dose, 3 mid-dose and 1 high-dose male did not generate F1 pups. The male fertility index ra
nged from 88-96% without showing any relation to the dosing. The infertile male rats did not show histopathological findings that could explain infertility. One male of the low-dose had an oligosperma
and debris within the tubules of the testes.
The female mating index calculated after mating period of F1 litter was 100% in all groups. The mean duration until sperm was detected varied from 2.3 and 2.6 days without any relation to dosing. All sperm positive rats delivered pups or had implants in utero (except 3 control 3 low-dose, 3 mid-dose and 1 high-dose female which did not become pregnant). The fertility index varied between 88 and 96%.
There were no corroborative histopathological findings in the sexual organs of the non-pregnant females. The mean duration of gestation varied between 22.0 and 22.2 days without any relation to dosing.
Implanation was not affected by treatment since the number of implanation sites was comparable to control. There were no indications for test item-related intrauterine embryo-/fetolethality since po
stimplantation loss did not show any statistically significant differences between the groups. The mean number of F1 pups delivered per dam remained unaffected. The rate of liveborn pups was also
not affected by treatment with the test item, as indicated by live birth index of 99 (control, mid- and high-dose) and 100% (low-dose). Moreover, the number of stillborn pups was comparable between the groups.
Under the conditions of the present 2-generation reproduction toxicity study the NOAEL (no observed adverse effect level) for general, systemic toxicity is 400 mg/kg bw/d for the F0 parental rats, the highest dose tested.
The NOEL (no observed effect level) is 50 mg/kg bw/d for the F0 parental rats based on effects on food consumption being a consequence of reduced appetite observed at the LOEL (Lowest Observed Effect Level) of 150 mg/kg bw/d in the F0 parental females.
The NOAEL for fertility and reproductive performance for the F0 parental rats is 400 mg/kg bw/d, the highest dose tested.
Dose descriptor:
NOEL
Remarks:
food consumption
Effect level:
50 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
food consumption and compound intake
Dose descriptor:
LOEL
Remarks:
food consumption
Effect level:
150 mg/kg bw/day
Based on:
test mat.
Sex:
female
Basis for effect level:
food consumption and compound intake
Remarks on result:
other: consequence of reduced appetite observed in the F0 parental females
Key result
Dose descriptor:
NOAEL
Remarks:
fertility and reproductive performance
Effect level:
400 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: no adverse effects observed
Dose descriptor:
NOAEL
Remarks:
General systemic toxicity
Effect level:
400 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: no adverse effects observed
Critical effects observed:
no
Clinical signs:
no effects observed
Description (incidence and severity):
24 out of 25 males and 12 out of 25 females of the high dose F1 parental animals showed transient salivation during major parts of the treatment period. Salivation persisted in the respective animals only
for some minutes after daily gavage (i.e. upto 15 minutes). The salivation persisted in the respective animals only for some minutes after daily gavage dosing (i.e. up to 15 minutes). This symptom was
initially observed during study week 6 in males and towards the end of the study in females.
The temporary salivation is considered to be test item-related. Form the temporary, short appearance immediately after dosing, it is likely that this finding was induced by the bad taste of the test item or
local affection of the upper digestivve tract. It was clearly considered to be not an adverse toxicological finding. Other clinical findings like labored respiration, microphthalmia, poor general state,
palpable mass in the neck and throat region in some low-and mid-dose individuals were considered as spontaneous in nature and not as test item-related.
Clinical signs of females in females during gestation of F2 litters:
Five out of 25 high dose females showed transient salivation during major parts of the gestation period (GD 4, 6-7, 9 and 11-12). There were no clinical signs in low and mid-dose females.
Clinical signs of females and offspring during lactation of F2 litters:
There were no clinical findings in F1 females during the lacation period for the F2 litters at all dose levels.
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Description (incidence):
There were not deaths observed in the F1 parental dose groups.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
HIgh dose F1 parental males had statistically significantly lower body weights during week 0-5 (up to 17%) and 10-11 (up to 6%). Mean body weight gain of these parental males was comparable to
control group throughout the entire study.
Mean body weights and body weight gain of F1 parental males in the low and mid dose were comparable to control throughout the entire study.
HIgh dose F1 parental females had statistically significantly lower body weights during premating week 0-1 (up to 16%). High dose females' body weights were comparable to control group during
remaining premating, entire gestation and lacation period. Mean body weight gain of these parental females was comparable to control animals.
Mean body weights and body weight gain of F1 parental males in the low and mid dose were comparable to control throughout the entire study. The statistically significantly increased body weight gain of
high dose females during premating weeks 1-2 and premating weeks 0-10 was considered as spontaneous in nature.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Test group 03 (400 mg/kg bw/d)
Statistically significantly decreased food consumption in parental males during premating weeks 0 - 1 (about 14%) and weeks 8 - 10 (up to 7%)
• Statistically significantly decreased food consumption in parental females during premating weeks 0
- 1 (about 10%) and weeks 9 - 10 (about 8%)
• Statistically significantly decreased food consumption in parental females during gestation days 0 - 14 (up to 8%)
• Statistically significantly decreased body weights in parental males during weeks 0 - 5 (up to 17%) a nd weeks 10 - 11 (up to 6%)
• Statistically significantly decreased body weights in parental females during premating weeks 0 - 1 (up to 16%)
Test group 02 (150 mg/kg bw/d)
• no test substance-related adverse effects/findings
Test group 01 (50 mg/kg bw/d)
• no test substance-related adverse effects/findings
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:
effects observed, non-treatment-related
Description (incidence and severity):
Absolute organ weights
Group male animals female animals
50 150 400 50 150 400
_________________________________________________________________________________________
Body weight -1% -5% -7%**
Liver +3% +9%** +10%**
Kidney +7%** +12%** +12%**
Brain 0% -2% -3%*
Cauda epididymis +7%* +7%* +6%*
*:p<=0.05 **:p<=0.01
All other mean absolute weight parameters did not show any significant differences compared to control.
The increase of absolute liver and kidney weights of females were considered as treatment-related.
The increase of cauda epididymis weight in all treated males is considered incidental and not treatment-related as there was no histopathologic correlate observed. The decrease of brain weights in highdose males is regarded to be a consequence of the reduced terminal body weight.
Relative organ weights
Group male animals female animals
50 150 400 50 150 400
_________________________________________________________________________________________
Liver -1% +3% +5%* +3%* +9%** +13%**
Kidney 0% +5%* +10%** +6%** +12%** +15%**
Epididymides +5%* +7%* +7%**
Cauda epididymides +8%* +13%** +14%**
*:p<=0.05 **:p<=0.01

All other parameters did not show significant differences in comparison to control.
The increase relative liver and kidney weights of females of all treated groups was regarded as treatment-related. The increase in liver weight in high-dose males and of kindey in mid- and high-dose males were considered to be treatment-related. The increase of epididymides in all treated males were thought to be reflective to the lower body weight. In addition, there was no histopathologic correlate corresponding to the weight decrease in the high-dose group.
Gross pathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
All gross lesions observed in test animals occured singularly. They are considered to be spontaneous lesions in origin and are not related to treatment.
The females that were not pregnant and the mating partners did not show relevant gross lesions.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, non-treatment-related
Description (incidence and severity):
All findings were single observations either or were similarly in distribution pattern and severity in control rats compared to treatment groups. All of them are considered to be incidental and/ or sp
ontaneous in origin and without any relation to treatment.
The non-pregant females and the male mating partners did not show any histopathologic lesion that could explan the infertility.
Descendents: In the F1 generation, all animals survived until the end of the study.
Histopathological findings: neoplastic:
not examined
Reproductive function: oestrous cycle:
no effects observed
Description (incidence and severity):
Oestrus cylce data, generated during the last 3 weeks prior to mating for the F2 litter, revealed regular cycles in the females of all groups. The mean oestrus cycle duration was similar: 4.1 (control), 4.2 (lo
w-dose), 4.3 (mid-dose) and 4.1 days (high-dose).
Reproductive function: sperm measures:
no effects observed
Description (incidence and severity):
No test item-related effects were noted for the different sperm measures examined at or after the sacrifice of the parental F1 males. The number of homogenisation resistend testicular spermatids or ca
udal epididymal sperm, the percentages of abnormal and normal sperm and sperm motility data were comparable to control animals
Reproductive performance:
no effects observed
Description (incidence and severity):
For all F1 males, copulation was confirmed. The male mating index is 100%. Fertility was proven for most of the F1 males within the scheduled mating interval for F2 litter. One control, one low-dose and
one high-dose male did not generate F2 pups. The male fertility index ranges from 96-100 % without any relation to dosing. This reflects the normal range of biological variation inherent in the strain of rats used for the study. All respective values are within the range of historical control data of the test laboratory. The apparently infertile males did not show histopathological findings that could explain infertility.
The female mating index calculated after the mating period for F2 litter was 100% in all dose group s. The mean duration until sperm was detected (GD 0) varied between 2.2 and 2.8 days without any
relation to dosing. All sperm positive rats delivered pups or had implants in utero, except one control, one low-dose and one high-dose female rat.
The female fertility index ranges from 96 (control, low and high-dose) to 100 (mid-dose) % without any relation to dosing. This reflects the normal range of biological variation inherent in the strain of
rats used for the study. All respective values are within the range of historical control data of the test laboratory. The apparently non pregnant females did not show histopathological findings.
The mean duration of gestation values varied from 22.0 and 22.2 days without any relation to dosing.
The gestation index was 100% in all dose groups.
Implanation was not affected by treatment since the number of implanation sites was comparable to control. There were no indications for test item-related intrauterine embryo-/fetolethality since pos
timplantation loss did not show any statistically significant differences between the groups. The mean number of F2 pups delivered per dam remained unaffected. The rate of liveborn pups was also
not affected by treatment with the test item, as indicated by live birth index of 99% in all dose groups.
Moreover, the number of stillborn pups was comparable between the groups.
Dose descriptor:
NOAEL
Remarks:
general toxicity
Effect level:
400 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no effect observed
Dose descriptor:
NOAEL
Remarks:
fertility and reproductive performace
Effect level:
400 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no effect observed
Critical effects observed:
no
Clinical signs:
no effects observed
Description (incidence and severity):
The F1 pups did not display any treatment-related clinical signs until weaning. One pup of the control group displayed a domed head on PND 14-16 and was cannibalised on PND 16.
Dermal irritation (if dermal study):
not examined
Mortality / viability:
no mortality observed
Description (incidence and severity):
The viability index indication pup mortality during early lactation (OND 0-4) varied between 100 (low dose) and 99% (other dose groups). The lacation index indicating pup mortality on PND 4-21 varied
between 100 (low-dose), 99 (control), 97 (mid-dose) and 92%**(high-dose). The statistically significant decreased lactation index in the high-dose group was caused by the non test item-related death
of 2 dams on PND 13 and 18, the litters of which had to be sacrified. These litters losses were considered as spontaneous in nature.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
No test item-related influence on F1 pup body weight was noted in all treated groups. Mean body weight gain of low and mid-dose pups was comparable to control group. A temporary decrease of mean
body weight gain was noted for the high dose pups on PND 4-7. Considering the absence of significant differences in weights themselves, these decreases were regarded as incidential and non treatment-related.
Food consumption and compound intake (if feeding study):
not examined
Description (incidence and severity):
The food consumption of the parental F1 animals is reported above.


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
Sexual maturation:
no effects observed
Description (incidence and severity):
The first day when vaginal opening was observed was PND 28, the last was PND 42. The mean age at vaginal patency was 31.6, 33.0, 33.2* and 33.9* days in the control, low-, mid- and high-dose,
respectively. The mean body weight on the day, when vaginal patency was noted, amounted to 95.5, 101.4, 101.5 and 98.1 g in the control, low-, mid- and high-dose, respectively. This minimal apparent
increase in the high-dose group is considered secondary to the lower female body weight during major phase of sexual maturation.
The first day of preputial separation was observed was PND 39, the last was PND 49. The mean number of days to reach the criterion in the control and 50, 150 and 400 mg/kg bw/d test group was 41.6, 41.4, 41.6 and 42.5 days, indication that male sexual maturation was not influenced by the test item. The mean body weight, when preputial separation was recorded, amounted to 171.1, 168.9, 166.9 and 162.2*g. All ages and corresponding body weight values were either below or at the lower end of the historical control range. The significantly low high-dose body weight corresponds to the slightly, but not-significantly, later high-dose male sexual maturation.
Anogenital distance (AGD):
not specified
Nipple retention in male pups:
not specified
Organ weight findings including organ / body weight ratios:
no effects observed
Description (incidence and severity):
The absolute organ weight of the brain were statistically significant changed in comparison to the control.
absolute brain weight (male +female): 99%( low-dose); 97% (mid-dose); 97% * (high-dose)
absolute brain weight (male): 99% (low-dose); 95%*(mid-dose); 96%*(high-dose)
These marginal differences in absolute brain weights reflect normal biological variation in this strain of rats as they are comparable to historical control data. Relative brain weights remained unchanged.
These findings are neither adverse nor toxicologially relevant.
Gross pathological findings:
no effects observed
Description (incidence and severity):
A few F1 pups showed spontaneous findings in gross necropsy (e.g. situs inversus, supernumerary lung lobe, small kidney, enlarged kidney). There findings occured without any relation to dosing and/
or can be found in the historical control data at comparable or even higher incidences. Therefore, the se findings were not considered to be associated to the test item.
Histopathological findings:
no effects observed
Behaviour (functional findings):
not specified
Developmental immunotoxicity:
not specified
The NOEL (no observed effect level) is 50 mg/kg bw/d for the F1 parental rats based on effects on food consumption being a consequence of reduced appetite observed at the LOEL (Lowest Observed Effect Level) of 150 mg/kg bw/d in the F0 parental females.
The NOAEL for fertility and reproductive performance for the F1 parental rats is 400 mg/kg bw/d, the highest dose tested.
The NOAEL for developmental toxicity, in the F1 of the test substance is 400 mg/kg bw/d, the highest dose tested.
Dose descriptor:
NOEL
Remarks:
food consumption
Generation:
F1
Effect level:
50 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
food consumption and compound intake
Remarks on result:
other:
Remarks:
effects on food consumption beeing a consequence of reduced appetite observed at the LOEL of 150 mg/kg bw/d in the F0 parental females
Key result
Dose descriptor:
NOAEL
Remarks:
developmental
Generation:
F1
Effect level:
400 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: no adverse effects observed
Critical effects observed:
no
Clinical signs:
no effects observed
Description (incidence and severity):
The F2 pups did not show any treatment-related clinical signs until weaning. Female pup of one control dam had multiple malformed left hindlimb and for one female pup of a high-dose dam a lateral posi
tion on one occasion during lactation (OND 19) was recorded.
Dermal irritation (if dermal study):
not examined
Mortality / viability:
no mortality observed
Description (incidence and severity):
The viability index indicating pup mortality during early lactation (OND 0-4) varied between 98 (lowdose) and 99% (other dose groups). The lactation index indicating pup mortality on OND 4-21 varied
between 98 (low-and mid-dose), 99 (high-dose) and 100% (control). The statistically significantly in creased number of cannibalised pups in the low-dose was considered as spontaneous in nature.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
No test item-related influence of F2 pup body weight was noted in all dose groups. Temporary decreases of mean body weight change were noted in F2 male and/or female pups of high-dose
group on PND 1-4 and PND 4-7 as well as in low-dose group on PND 14-21. Considering the absence of significant differences in the weights themselves, these decreases were regardrd as incidental and not treatment-related.
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
Sexual maturation:
not examined
Anogenital distance (AGD):
not examined
Nipple retention in male pups:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Description (incidence and severity):
There were no changes in absolute or relative organ weights noted in any of the dose groups.
Gross pathological findings:
no effects observed
Description (incidence and severity):
Single F2 pups showed some spontaneous findings at gross necropsy such as incisors sloped, hemorrhagic thymus, diaphragmatic hernia, empty stomach, dilated renal pelvis, dilated ureter,
small testis, haematoma and multiple malformed hindlimb. Every pup necropsy finding occured without any relation to dosing and/ or can be found in the historical control data at comparable or even higher incidences.
Histopathological findings:
not examined
Other effects:
no effects observed
Description (incidence and severity):
The sex distribution and sex ratios of live F2 pups on day of birth and PND 21 were comparable to control group.
Behaviour (functional findings):
not examined
Developmental immunotoxicity:
not examined
Key result
Dose descriptor:
NOAEL
Remarks:
prenatal developmental toxicity
Generation:
F2
Effect level:
400 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no adverse effects observed
Critical effects observed:
no
Reproductive effects observed:
no

- Analytics:

The various analyses:

  • demonstrated the stability of the test substance preparations over a period of 7 days at room temperature
  • confirmed the homogeneous distribution of the test substance in the vehicle (1% Carboxymethylcellulose suspension in drinking water and a few drops Cremophor EL and one drop hydrochloric acid)
  • showed that the prepared concentrations were close to the expected values ranging between 86.8 and 113.2% of the nominal concentrations

Analytical values (range):

Test group

Nominal Dose
(mg/kg bw/d)

Analytical Dose
(mg/kg bw/d)
[minimum]

Analytical Dose (mg/kg bw/d)
[maximum]

% Nominal Dose
[minimum]

% Nominal Dose
[maximum]

00 / 10

0

0

0

 

   

01 / 11

50

43.40

46.61

86.8

93.2

02 / 12

150

132.90

169.80

88.6

113.2

03 / 13

400

359.20

379.90

89.8

95.0

 

Conclusions:
The NOAEL for general, systemic toxicity is 400 mg/kg/d for the parental rats in the highest dose tested.
The NOEL 50 mg/kg bw/day for the P parental rats, based on effects on food consumption observed at the LOAEL of 150 mg/kg bw/day in the P parental females.
The NOAEL for fertility and reproductive performance for the P and F1 parental rats is 400 mg/kg bw/day, the highest dose tested.
The NOAEL for developmental toxicity, in the F1 and F2 progeny, of the test substance is 400 mg/kg bw/day, the highest dose tested.
Executive summary:

The study was performed according to OECD TG 416 in compliance with GLP. Methyl Methacrylate was administered to groups of 25 male and 25 female healthy young Wistar rats (P parental generation) as an aqueous preparation by stomach tube at dosages of 0; 50; 150 and 400 mg/kg body weight/day. At least 73 days after the beginning of treatment, P animals were mated to produce a litter (F1). Mating pairs were from the same dose group and F1 animals selected for breeding were continued in the same dose group as their parents. Groups of 25 males and 25 females, selected from F1 pups to become F1 parental generation, were treated with the test substance at dosages of 0; 50; 150 and 400 mg/kg body weight/day post weaning, and the breeding program was repeated to produce F2 litter. The study was terminated with the terminal sacrifice of the F2 weanlings and F1 adult animals.

Control parental animals were dosed daily with the vehicle (1% Carboxymethylcellulose suspension in drinking water and four drops Cremophor EL and one drop hydrochloric acid).

The mid- and high-dose parental animals (400 mg/kg bw/d) showed clinical signs of systemic toxicity. The only relevant clinical observation was temporary salivation during a short period after dosing, which is considered to be test substance-induced. From the temporary, short appearance immediately after dosing it is likely, that this finding was induced by a bad taste of the test substance or local affection of the upper digestive tract. It is, however, not considered to be an adverse toxicologically relevant finding.

In the mid- and high-dose (150 and 400 mg/kg bw/d) P generation animals, dose-related intermittent reductions of food consumption were noted, either during premating, gestation and lactation phases of this study. Less significant changes were noted for the F1 generation animals where the effects were limited to the high-dose group.

High dose F1 parental males had statistically significant lower body weights during several study segments, which led to a statistically significant reduction of the mean terminal body weight resulting in secondary weight changes of brain.

High dose parental females had statistically significant lower body weights during the first weeks after weaning. This weight decrease during major phases of sexual maturation led to an apparent marginal delay of vaginal patency. This minor delay did, however, not result in any corroborative pathological findings nor did it adversly effect F1 female cyclicity, fertility and reproduction. Thus, an influence of the test substance on female sexual maturation is not assumed.

Pathological examinations revealed no test-substance-related changes in organ weights, gross lesions, changes in differential ovarian follicle counts or microscopic findings, apart from an increase in kidney and liver weights in male and female animals in both generations which is presumably related to the treatment. There was no histopathologic lesion observed, that could explain the weight increase. It is regarded to be an adaptive change, most likely caused by an increase in metabolic activity in the two organs, which does not lead to histopathologic findings. It is not regarded to be an adverse effect.

There were no indications from clinical examinations as well as gross and histopathology, that the administration of methyl methacrylate via the diet adversely affected the fertility or reproductive performance of the P or F1 parental animals up to and including a dose of 400 mg/kg bw/day. Estrous cycle data, mating behavior, conception, gestation, parturition, lactation and weaning as well as sperm parameters, sexual organ weights and gross and histopathological findings of these organs (including differential ovarian follicle counts in the F1 females) were comparable between the rats of all test groups and ranged within the historical control data of the test facility.

All data recorded during gestation and lactation in terms of embryo-/fetal and pup development gave no indications for any developmental toxicity in the F1 and F2 offspring up to a dose level of 400 mg/kg bw/day. Up to this dose level, the test substance did not adversely influence pup viability and pup body weights. Sex ratio and sexual maturation was not directly affected at any dose level, inclusive the high-dose group (400 mg/kg bw/day).

Conclusion:

Under the conditions of the present 2-generation reproduction toxicity study the NOAEL(no observed adverse effect level) forgeneral, systemic toxicityis 400 mg/kg bw/d for the parental rats, the highest dose tested.

The NOEL (no observed effect level) is 50 mg/kg bw/d for the F1 parental rats based on effects on food consumption being a consequence of reduced appetite observed at the LOEL (Lowest Observed Effect Level) of 150 mg/kg bw/d in the F0 parental females.

The NOAEL for fertility and reproductive performance for the F1 parental rats is 400 mg/kg bw/d, the highest dose tested.

 The NOAEL for developmental toxicity, in the F1 of the test substance is 400 mg/kg bw/d, the highest dose tested.

Effect on fertility: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
400 mg/kg bw/day
Species:
rat
Quality of whole database:
reliable without restrictions
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

Methyl methacrylate has been tested in a reliable two-generation reproduction toxicity study in rats with oral administration (gavage). The study was performed according to OECD TG 416 in compliance with GLP (REACH Methyacrylate Task Force, 2009). In this study, Methyl Methacrylate was administered to groups of 25 male and 25 female healthy young Wistar rats (P parental generation) as an aqueous preparation by stomach tube at dosages of 0; 50; 150 and 400 mg/kg body weight/day. At least 73 days after the beginning of treatment, P animals were mated to produce a litter (F1). Mating pairs were from the same dose group and F1 animals selected for breeding were continued in the same dose group as their parents.

Groups of 25 males and 25 females, selected from F1 pups to become F1 parental generation, were treated with the test substance at dosages of 0; 50; 150 and 400 mg/kg body weight/day post weaning, and the breeding program was repeated to produce F2 litter. The study was terminated with the terminal sacrifice of the F2 weanlings and F1 adult animals.

Control parental animals were dosed daily with the vehicle (1% Carboxymethylcellulose suspension in drinking water and four drops Cremophor EL and one drop hydrochloric acid).

The mid- and high-dose parental animals (400 mg/kg bw/d) showed clinical signs of systemic toxicity. The only relevant clinical observation was temporary salivation during a short period after dosing, which is considered to be test substance-induced. From the temporary, short appearance immediately after dosing it is likely, that this finding was induced by a bad taste of the test substance or local affection of the upper digestive tract. It is, however, not considered to be an adverse toxicologically relevant finding.

In the mid- and high-dose (150 and 400 mg/kg bw/d) P generation animals, dose-related intermittent reductions of food consumption were noted, either during premating, gestation and lactation phases of this study. Less significant changes were noted for the F1 generation animals where the effects were limited to the high-dose group. High-dose F1 parental males had statistically significant lower body weights during several study segments, which led to a statistically significant reduction of the mean terminal body weight resulting in secondary weight changes of brain. High-dose parental females had statistically significant lower body weights during the first weeks after weaning. This weight decrease during major phases of sexual maturation led to an apparent marginal delay of vaginal patency. This minor delay did, however, not result in any corroborative pathological findings nor did it adversly effect F1 female cyclicity, fertility and reproduction. Thus, an influence of the test substance on female sexual maturation is not assumed. Pathological examinations revealed no test-substance-related changes in organ weights, gross lesions, changes in differential ovarian follicle counts or microscopic findings, apart from an increase in kidney and liver weights in male and female animals in both generations which is presumably related to the treatment. There was no histopathologic lesion observed, that could explain the weight increase. It is regarded to be an adaptive change, most likely caused by an increase in metabolic activity in the two organs, which does not lead to histopathologic findings. It is not regarded to be an adverse effect. There were no indications from clinical examinations as well as gross and histopathology, that the administration of methyl methacrylate via the diet adversely affected the fertility or reproductive performance of the P or F1 parental animals up to and including a dose of 400 mg/kg bw/day. Estrous cycle data, mating behavior, conception, gestation, parturition, lactation and weaning as well as sperm parameters, sexual organ weights and gross and histopathological findings of these organs (including differential ovarian follicle counts in the F1 females) were comparable between the rats of all test groups and ranged within the historical control data of the test facility. All data recorded during gestation and lactation in terms of embryo-/fetal and pup development gave no indications for any developmental toxicity in the F1 and F2 offspring up to a dose level of 400 mg/kg bw/day. Up to this dose level, the test substance did not adversely influence pup viability and pup body weights. Sex ratio and sexual maturation was not directly affected at any dose level, inclusive the high-dose group (400 mg/kg bw/day).

The NOAEL for general, systemic toxicity was determined to be 50 mg/kg bw/day for the P and F1 parental rats, based on adverse effects on food consumption observed at the LOAEL of 150 mg/kg bw/day in the P parental females. The NOAEL for fertility and reproductive performance for the P and F1 parental rats was determined to be 400 mg/kg bw/day, the highest dose tested. The NOAEL for developmental toxicity, in the F1 and F2 progeny, of the test substance was determined to be 400 mg/kg bw/day, the highest dose tested.


Effects on developmental toxicity

Description of key information

rodent data: rat, inhalation, according to OECD 414 (Solomon 1991)

LOAEC maternal toxicity = ca. 410 mg/m3 (corresponding to 99 ppm) due to decreased food consumption and associated reduced body weight gain)

NOAEC developmental toxicity >= ca. 8,300 mg/m3 (corresponding to ca. 2028 ppm) in absence of adverse effects

non-rodent data: rabbit, oral, according OECD 414 (REACH Methacrylate Task Force, 2009)

NOAEL maternal toxicity = 50 mg/kg bw (due to decreased food consumption and associated reduced body weight gain)

NOAEL developmental toxicity = 450 mg/kg bw in absence of adverse effects

Link to relevant study records

Referenceopen allclose all

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes
Specific details on test material used for the study:
- Supplier: Rohm and Haas Company
- Purity= 99.9 %
Species:
rat
Analytical verification of doses or concentrations:
yes
Details on study design:
.
Clinical signs:
no effects observed
Description (incidence and severity):
No treatment-related clinical signs were observed bevore, during, or after the exposures at any exposure levels tested.
The only clinical sign noted was a minimal (only noted once or twice in 6 of 7 affected females) increase in the incidence of scant feces at 2028 ppm.
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Description (incidence):
There were no test substance-related or spontaneous mortalities in any group.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Treatment-related decreases on maternal body weight and feed consumption were noted at all exposure levels. The decreases in maternal body weight at 99 and 304 ppm were minimal and transient since they occurred only during the first 2 days of exposure and returned to control values by the next weighing period. In addition, maternal body weight gain over the entire treatment period (days 6-16 G) and corrected maternal body weight gain at 99 and 304 ppm were similar to the control values. The body weight and feed consumption values returned to control values for all groups during the post exposure period (GD 16-20). At 1178 and 2028 ppm, treatment-related effects included losses in maternal body and/or decreased body weight gain throughout the exposure period (GD 6 - 16) and decreased corrected maternal body weight gain (body weight gain minus gravid uterine weight).

Body weight during gestation in rats inhaling Methyl methacrylate on days 6 to 15 of gestation and euthanized on day 20:
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Concentrations No of dams Mean Body weight [g] ± SD
[ppm], 6 h/day on GD 0 on GD 6 on GD 8 on GD 10 on GD 13 on GD 16 on GD 20
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
0 25 244.7 ±3.13 285.6 ± 3.93 295.4 ±4.33 307.1 ±4.20 327.3 ±4.68 350.6 ±5.05 414.2 ±6.84
99 23 246.3 ±2.93 286.1 ± 3.56 289.9 ±4.01 304.8 ±3.99 325.4 ±4.31 351.8 ±4.72 416.6 ±6.87
304 22 248.7 ±2.62 286.2 ± 3.11 288.9 ±3.60 301.3 ±3.91 321.1 ±4.09 347.1 ±4.58 413.9 ±6.09
1178 23 244.9 ± 2.77 282.2 ± 3.53 278.1a ±3.96 289.0a ±3.94 308.3a ±4.04 334.6 ±4.88 400.4 ±6.80
2028 23 246.7 ± 2.85 286.4 ± 3.03 275.2a ±2.68 280.9a ±3.40 306.2a ±3.49 332.7a ±4.27 401.3 ±5.56
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
a Denote significant differences from the control (0 ppm), p < 0.05, respectively.


Change in weight during gestation in rats inhaling Methyl methacrylate on days 6 to 15 of gestation and euthanized on day 20:
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Concentrations No of dams Mean body weight gain ± SD on GD [g]
[ppm], 6 h/day on GD 0 - 6 on GD 6 - 8 on GD 8 - 10 on GD 10-13 on GD 13-16 on GD 6-16 on GD 16-20
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
0 25 41.0 ±1.86 9.8 ±0.83 11.6 ±0.58 20.3 ±0.94 23.2 ±1.76 65.0 ±2.33 63.6 ±2.75
99 23 39.7 ±2.36 3.8a ±1.39 15.0 ±1.90 20.5 ±1.28 26.4 ±1.52 65.7 ±2.83 64.8 ±3.81
304 22 37.5 ±2.05 2.7a ±1.09 12.4 ±1.09 19.8 ±1.04 26.0 ±1.30 60.9 ±2.62 66.8 ±2.54
1178 23 37.3 ±1.91 -4.1a ±-1.41 10.9 ±0.91 19.3 ±1.09 26.3 ±1.76 52.4a ±2.56 65.8 ±3.15
2028 23 39.7 ±1.08 -11.2a ±0.88 5.7a ±2.24 25.4a ±1.62 26.5 ±1.99 46.4a ±2.35 68.6 ±2.12
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
a Denote significant differences from the control (0 ppm), p < 0.05, respectively.


Summary of Uterine and Net body weights in rats inhaling Methyl methacrylate on days 6 to 15 of gestation and euthanized on day 20:
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Concentrations No of dams Gravid Uterus weight ± SD [g] Corrected Mean body weight ± SD on GD 20 [g] Net weight change ± SD from GD 6 [g]
[ppm], 6 h/day
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
0 25 82.7 ±3.81 331.5 ±4.77 45.8 ±2.21
99 23 82.7±5.76 333.9 ±5.08 47.9 ±2.76
304 22 86.4 ±3.75 327.5 ±4.71 41.3 ±2.73
1178 23 79.9 ±5.04 320.5 ±5.04 38.3 ±3.04
2028 23 84.5 ±3.62 316.8 ±3.60 30.4a ±2.25
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
a Denote significant differences from the control (0 ppm), p < 0.05, respectively.

Corrected body weight: terminal body weight at GD 20 minus Uterine weight
Net weight change from GD 6: Corrected body weight minus day 6 body weight
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
Treatment related decrease waere noted on feed consumption between days 6-10 G at all exposure levels teasted. Decteases in feed consumption continued between days 6-10 G at 304, 1178, and 2028 ppm. Feed consumption of all treated groups returend to control value during post-treatment period (days 16-20 G)
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 specified
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Number of abortions:
no effects observed
Description (incidence and severity):
There were no abortions observed in any of the treated dose groups.
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
The pre- and postimplantation loss was unaffected by treatment.
Total litter losses by resorption:
no effects observed
Description (incidence and severity):
In the study, there was one dam high-dose dam with total litter loss. This observation is considered as not treatment-related.
Early or late resorptions:
no effects observed
Description (incidence and severity):
In the study, there were no early or late resorptions observed.
Dead fetuses:
no effects observed
Description (incidence and severity):
There were no dead fetuses found in the uterine.
Changes in pregnancy duration:
not specified
Description (incidence and severity):
There was a Caesarian section performed on GD 20.
Changes in number of pregnant:
no effects observed
Details on maternal toxic effects:
Details on maternal toxic effects:
No animals died and no treatment-related clinical signs were noted for the dams in the 99, 304 or 1178 ppm groups. Scant feces was noted in the 2028 ppm group throughout the exposure period (GD 6-15). Treatment-related decreases on maternal body weight and feed consumption were noted at all exposure levels. The decreases in maternal body weight at 99 and 304 ppm were minimal and transient since they occurred only during the first 2 days of exposure and returned to control values by the  next weighing period. The body weight and feed consumption values returned to control values for all groups during the post exposure period  (GD 16-20). At 1178 and 2028 ppm, treatment-related effects included losses in maternal body and/or decreased body weight gain throughout the exposure period (GD 6 - 16) and decreased corrected maternal body weight gain. The gross necropsy evaluations did not indicate any treatment-related effects and there were no treatment-related differences between the control and treated groups in any reproductive parameter.  
Dose descriptor:
LOEC
Remarks:
maternal toxicity
Effect level:
ca. 0.41 mg/L air (analytical)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOAEC
Remarks:
maternal toxicity
Effect level:
8.44 mg/L air (analytical)
Based on:
test mat.
Remarks on result:
other: no adverse effects observed
Abnormalities:
no effects observed
Fetal body weight changes:
no effects observed
Description (incidence and severity):
There were no treatment-related effects on fetal body weight in males, females and both sexes combined at any dose level tested.
Reduction in number of live offspring:
no effects observed
Description (incidence and severity):
Reproductive parameters in rats inhaling Methyl methacrylate on days 6 to 15 of gestation and euthanized on day 20:
--------------------------------------------------------------------------------------------------------------------------------------
Concentrations No of litters No. of live fetuses per litter
[ppm], 6 h/day
------------------------------------------------------------------------------------------------------------------------------------
0 25 13.88
99 23 13.87
304 22 14.86
1178 23 13.70
2028 23 14.65
-----------------------------------------------------------------------------------------------------------------------------------
Changes in sex ratio:
no effects observed
Description (incidence and severity):
There were no treatment-related changes in the sex ratio observed at any dose group.
Changes in litter size and weights:
no effects observed
Description (incidence and severity):
The mean number of pups per litter and litter weight were unaffected by treatment.
Changes in postnatal survival:
no effects observed
Description (incidence and severity):
The pups were euthanised shortly after the Caesarian section.
External malformations:
effects observed, non-treatment-related
Description (incidence and severity):
No treatment-related increase were detected in the type of external, visceral, or skeletal malformations.
Spontaneous malformations detected in the study included duplicated hypothalamus in a control fetus, hydrocephaly in a fetus at 304 ppm and an omphalocele in one fetus and enlarged adrenal glands in two fetuses at 1178 ppm was not considered to be treatment related as at 2028 ppm no increase was observed.
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
The significant increase in skeletal developmental variations at 1178 ppm was not detected at 2028 ppm, the highest doese tested. The slightly, not statistically significant number of fetuses with partial or unossified sternebra at 304 ppm was not considered a result of treatment since no dose response was demonstrated.
Visceral malformations:
no effects observed
Description (incidence and severity):
There were no visceral malformations observed in any of the dose groups.
Other effects:
not specified
Details on embryotoxic / teratogenic effects:
Details on embryotoxic / teratogenic effects:
 Fetal body weight was not affected by exposure to MMA vapors. The fetal external, visceral and skeletal examinations did not show any treatment related effects.
Dose descriptor:
NOAEC
Remarks:
fetotoxicity
Effect level:
8.44 mg/L air (analytical)
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: corresponding to 2028 ppm; no substance related effects observed
Key result
Dose descriptor:
NOAEC
Remarks:
teratogenicity
Effect level:
8.44 mg/L air (analytical)
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: corresponding to 2028 ppm; no substance related effects observed
Abnormalities:
no effects observed
Developmental effects observed:
no

Mean measured concentrations (± SD) within the chambers for the 0, 100, 300, 1200 and 2000 ppm groups were 98.8 (±3.4), 304.4 (±9.1), 1178.1  (±69.1) and 2028.2 (±107.3) ppm, respectively.

Conclusions:
Exposure by inhalation to methyl methacrylate concentrations up to 8.44 mg/L (2028 ppm) resulted in no embryo or fetal toxicity or malformations even at exposure levels that resulted in maternal toxicity.
Executive summary:

In a developmental toxicity study on rats acc. OECD 414 by inhalation pregnant CRl: CD Br rats rats were exposed to methyl methacrylate at concentrations of 0 (control), 99, 304, 1178 and 2028 ppm on days 6-15 of gestation. A maternal no observed level was not demonstrated since losses in maternal body weight or decreases in maternal body weight gain and decreases in maternal feed consumption were noted at all exposure levels tested. No embryo or fetal toxicity was evodent and no increase in the incidence of malformations or variations was noted at exposure levels up to the highest dose of 2028 ppm. Therefore toxicity to the conceptus was not evident even at expsoure levels that resulted in overt maternal toxicity.

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes
Specific details on test material used for the study:
Name of test substance: Methyl Methacrylate
Test substance No.: 07/0751-1
Batch identification: 012231eda0
CAS No.: 80-62-6
Purity: 99.9%
Homogeneity: Homogeneous
Expiry date: 16 Jan 2009
The stability of the test substance under storage
conditions over the test period was guaranteed by
the manufacturer, and the manufacturer holds this
responsibility.
Supplier: Sigma Aldrich
Species:
rabbit
Details on study design:
.
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Description (incidence):
There were no test substance-related or spontaneous mortalities in any group.
Body weight and weight changes:
no effects observed
Description (incidence and severity):
The mean body weights of the low-, mid- and high-dose rabbits (50; 150 and 450 mg/kg bw/d) were not significantly different from the concurrent control throughout the course of the study. The average body weight gain of the mid- and high-dose rabbits was statistically significantly reduced by about 27% and 31% during the treatment period. A significant reduction of mean body weight gain was also noted for the the high-dose rabbits on GD 19-21.

Corrected (net) body weight gain: Mean carcass weights and the corrected body weight gain (terminal body weight on GD 29 minus weight of the unopened uterus minus body weight on GD 6) were comparable among all groups.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
The food consumption in the high-dose females (450 mg/kg bw/d) was distinctly and statistically significantly reduced during a significant part of the treatment period (GD 15-23). During the entire treatment period (GD 6-28) the total average food consumption of the high dose rabbits was about 18% below controls. The food consumption of the mid dose females (150 mg/kg bw/d) was similarly affected in terms of magnitude and course of reduction, however the reduction of food consumption reached statistical significance only on GD 22-24. During the treatment period (GD 6-28) the total average food consumption of the mid-dose rabbits was about 13% below controls. Overall, the food consumption of the low-dose does (50 mg/kg bw/d) did not show test substance-related impairments. The reduced food consumption at the 150 and 450 mg/kg bw/d levels is considered to be related to the treatment.
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not specified
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Description (incidence and severity):
The mean gravid uterus weights of all test groups did not show staatistically significant differences in comparison to control.
Gross pathological findings:
no effects observed
Description (incidence and severity):
At necropsy, only spontaneous findings were seen in single females of every test group. No test substance-related findings were observed in the doses.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Number of abortions:
no effects observed
Description (incidence and severity):
There were no test item-related and/or biologically relevant differences between the control and the treated groups in conception rate, the mean number of corpora lutea, the mean number of implantati
on sites and/ or the calculated values for the pre- and postimplanation loss, the number of resorptions and viable fetuses. Gestational parameters were within the normal range for animals of this strain and age.
Pre- and post-implantation loss:
no effects observed
Description (incidence and severity):
There were no test item-related and/or biologically relevant differences between the control and the treated groups in conception rate, the mean number of corpora lutea, the mean number of implantati
on sites and/ or the calculated values for the pre- and postimplanation loss, the number of resorptions and viable fetuses. Gestational parameters were within the normal range for animals of this strain and age.
Total litter losses by resorption:
no effects observed
Description (incidence and severity):
There was no total litter loss by resoption obsevered in any of the does.
Early or late resorptions:
no effects observed
Description (incidence and severity):
There were no test item-related and/or biologically relevant differences between the control and the treated groups in conception rate, the mean number of corpora lutea, the mean number of implantati
on sites and/ or the calculated values for the pre- and postimplanation loss, the number of resorptions and viable fetuses. Gestational parameters were within the normal range for animals of this strain and age.
Dead fetuses:
no effects observed
Description (incidence and severity):
All fetuses were alive after euthanasia of the does.
Changes in pregnancy duration:
not examined
Description (incidence and severity):
In an OECD 414 study, a Caesarian section is performed.
Changes in number of pregnant:
no effects observed
Description (incidence and severity):
The conception rate reached 96% in test groups 1 and 3 (50 and 450 mg/kg bw/d) and 100% in test groups 0 and 2 (0 and 150 mg/kg bw/d). Importantly, a sufficient number of pregnant females was available for the purpose of the study, as 24-25 pregnant rabbits per group had implantation sites in the uterus, at terminal sacrifice. There were no test substance-related and/or biologically relevant differences between the control and all dosed groups in conception rate, in the mean number of corpora lutea and implantation sites or in the values calculated for the pre- and the postimplantation losses, the number of resorptions and viable fetuses. Gestational parameters were within the normal range for animals of this strain and age.
Dose descriptor:
NOAEL
Effect level:
450 mg/kg bw/day (nominal)
Based on:
test mat.
Remarks on result:
other: no adverse effects observed; actual dose 406 mg/kg/d
Dose descriptor:
NOEL
Remarks:
food consumption
Effect level:
50 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
food consumption and compound intake
Remarks on result:
other: actual dose: 41 mg/kg/d
Abnormalities:
no effects observed
Fetal body weight changes:
no effects observed
Description (incidence and severity):
The mean fetal weights of all treated groups were not influenced by the test substance. Neither female nor male weights showed statistically significant or biologically relevant differences between the test substance-treated groups and the controls.
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
no effects observed
Description (incidence and severity):
The sex distribution of the fetuses in test groups 1-3 (50; 150 and 450 mg/kg bw/d) was comparable to the control fetuses. Observable differences were without biological relevance.
Changes in litter size and weights:
no effects observed
Description (incidence and severity):
The mean fetal weight of all treated groups and the litter size were unaffected by the test item.
Changes in postnatal survival:
not examined
Description (incidence and severity):
In an OECD 414 study, the fetuses were euthanised immediately after the does' death.
External malformations:
effects observed, non-treatment-related
Description (incidence and severity):
One sole external malformation (unilateral microphthalmia) was recorded for two fetuses from 2 litters in the high-dose group (450 mg/kg bw/d). This malformation is present in the historical control data. Thus an association of these individual findings to the treatment is not assumed. The total incidences of external malformations were comparable to the historical control data.
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
Malformations of the fetal skeletons were noted in fetuses of test groups 0, 2 and 3 (0; 150 and 450 mg/kg bw/d). Neither statistically significant differences between treated groups and the control were calculated nor a dose-response relationship was observed. All individual skeletal malformations were present in the historical control data at a comparable frequency.
- Fetal skeletal variations: For all test groups, variations in different skeletal structures were detected with or without effects on the corresponding cartilages. The observed skeletal variations were related to various parts of the fetal skeletons and were statistically significant higher in the low- and the high-dose groups on a fetus per litter basis. Several specific skeletal variations were statistically significant higher than the concurrent control in the dosed groups (on a fetus per litter basis). These findings are delays or minor disturbances of ossification which are reversible or do not considerably affect the integrity of the underlying structures. Such slight changes of the ossification process occur very frequently in gestation day 29 rabbit fetuses of this strain and all observed incidences were within the historical control data. Thus an association of these findings to the treatment is not assumed.
- Fetal skeletal unclassified cartilage observations: Additionally, isolated cartilage findings without impact on the respective bony structures, which were designated as unclassified cartilage observations, occurred in all groups including the control. The observed unclassified cartilage findings did not show a relation to dosing and were comparable to historical control data and, therefore, regarded to be spontaneous in nature.
Visceral malformations:
no effects observed
Description (incidence and severity):
- Fetal soft tissue malformations: The examination of the soft tissues revealed a variety of malformations in fetuses of all test groups including the controls (0; 50; 150 and 450 mg/kg bw/d). With the exception of a lateral pouch in the tongue of 2 fetuses all individual soft tissue malformations were present in the historical control data at comparable frequencies. No statistically significant differences between the test groups and the control were observed. The total incidences of external malformations were comparable to the historical control data. No malformation pattern was evident. Thus an association of these findings to the treatment is not assumed.
- Fetal soft tissue variations: A number of soft tissue variations, such as absent lung lobe (lobus inferior medialis) and malpositioned carotid branch, was detected in each test group including the controls. Incidences were without a relation to dosing. Neither statistically significant differences between the test groups nor differences to the historical control data were noted.
- Fetal soft tissue unclassified observations: Unclassified soft tissue observations, such as infarct of liver, hemorrhagic thymus or ovary and blood coagulum around urinary bladder, were recorded for some fetuses of test groups 0, 1, 2 and 3 (0; 50; 150 and 450 mg/kg bw/d). A relation to dosing is not present if normal biological variation is taken into account. Therefore, a test substance induced effect is not assumed.
Details on embryotoxic / teratogenic effects:
- Abstract of all classified fetal external, soft tissue and skeletal observations: Various external, soft tissue and skeletal malformations occurred throughout all test groups including the control. All individual malformations are present in the historical control data, with the exception of lateral pouches in the tongue of 2 fetuses. They did neither show a consistent pattern since a number of morphological structures of different ontogenic origin were affected nor a clear dose-response relationship. The overall incidence of malformations was comparable to the historical control data. One external (paw hyperflexion), two soft tissue (absent lobus inferior medialis and malpositioned carotid branch) and a broad range of skeletal variations occurred in all test groups including the controls. All fetal and litter incidences for these variations and the corresponding mean percentages of affected fetuses/litter were not significantly different from the concurrent control and their frequency is comparable to the historical control data. Therefore, they were not considered to be related to the treatment. A spontaneous origin is also assumed for external, soft tissue and unclassified skeletal cartilage observations which were observed in several fetuses of all test groups including controls (0, 50; 150 and 450 mg/kg bw/d). Distribution and type of these findings do not suggest relation to treatment.
Key result
Dose descriptor:
NOAEL
Remarks:
prenatal developmental toxicity
Effect level:
450 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: no adverse effects observed
Abnormalities:
no effects observed
Developmental effects observed:
no

Table: Occurence of statistically significantly increased fetal skeletal variation (expressed as mean percentage of affected fetuses/litter)

Finding

Group 0

0 mg/kg/d

Group 1

50 mg/kg/d

Group 2

150 mg/kg/d

Group 3

450 mg/kg/d

HCD

(range)

Incomplete ossification of parietal; unchanged cartilage

0.0

0.0

1.9*

2.1*

0.4

(0.0 – 2.6)

Incomplete ossification of hyoid; cartilage present

11.2

11.4

19.1

20.4*

9.8

(0.0 – 21.6)

Splitting of skull bone

0.4

3.3*

3.3

2.3

2.9

(0.0 – 7.7)

Incomplete ossification of cervical centrum; unchanged cartilage

2.5

2.2

3.6

7.3*

2.5

(0.0 – 9.3)

Supemumerary 13th rib; cartilage not present

2.5

9.8

6.1

9.9*

6.6

(0.0 – 17.5)

Total fetal skeletal variations

46.3

63.7*

59.3

71.6**

63.5

(46.3 – 81.9)

HCD = Historical control data; * = p ≤ 0.05, ** = p ≤ 0.01 (Wilcoxon-Test [one-sided])

 

 

Table: Total fetal malformations

 

 

Group 0

0 mg/kg/d

Group 1

100 mg/kg/d

Group 2

300 mg/kg/d

Group 3

1000 mg/kg/d

Litter

Fetuses

N

N

25

171

24

154

25

157

24

158

Fetal incidence

N (%)

4 (2.3%)

2 (1.3%)

6 (3.8%)

9 (5.7%)

Litter incidence

N (%)

4 (16%)

1 (4.2%)

4 (16%)

7 (29%)

Affected fetuses/litter

Mean%

2.3

1.2

3.6

6.2

 

 

Table: Total fetal variations

 

 

Group 0

0 mg/kg/d

Group 1

100 mg/kg/d

Group 2

300 mg/kg/d

Group 3

1000 mg/kg/d

Litter

Fetuses

N

N

25

171

24

154

25

157

24

158

Fetal incidence

N (%)

106 (62%)

106 (69%)

106 (68%)

122 (77%)

Litter incidence

N (%)

21 (84%)

24 (100%)

24 (96%)

23 (96%)

Affected fetuses/litter

Mean%

59.9

69.8

64.3

74.2

 

Conclusions:
In conclusion, the no observed adverse effect level (NOAEL) for maternal toxicity is 450 mg/kg bw/d and the no observed effect level (NOEL) for maternal toxicity is 50 mg/kg bw/d based on effects on food consumption. The NOAEL for prenatal developmental toxicity is 450 mg/kg bw/d. No adverse fetal findings of toxicological relevance were evident at any dose.
Executive summary:

In a developmental toxicity study on rabbits  acc. OECD 414 methyl methacrylate was tested for its prenatal developmental toxicity in Himalayan rabbits. The test substance was administered as an aqueous preparation to 25 inseminated female Himalayan rabbits by stomach tube at doses of 50; 150 and 450 mg/kg body weight/day on gestation days (GD) 6 through GD 28. The control group, consisting of 25 females, was dosed with the vehicle (1% Carboxymethylcellulose CB 30.000 in drinking water and a few drops Cremophor EL and one drop hydrochloric acid [1% CMC]) in parallel. A standard dose volume of 10 mL/kg body weight was used for each test group. At terminal sacrifice on GD 29, 24-25 females per group had implantation sites.


The following test substance-related adverse effects/findings were noted:


Test group 3 (450 mg/kg body weight/day):


-        Reduced food consumption (-18%) and body weight gain (-31%)


-        No test substance-related adverse effects on gestational parameters or fetuses


 


Test group 2 (150 mg/kg body weight/day):


-        Reduced food consumption (-13%) and body weight gain (-27%)


-        No test substance-related adverse effects on gestational parameters or fetuses


 


Test group 1 (50 mg/kg body weight/day):


-        No test substance-related adverse effects on does, gestational parameters or fetuses


 


 


In conclusion, the no observed adverse effect level (NOAEL) for maternal toxicity is 450 mg/kg bw/d at nominal conebtratrtion corresponding to an actual concentration of 406 mg/kg bw/d, the highest dose tested. The no observed effect level (NOEL) for maternal toxicity is nominal 50 mg/kg bw/d (effective 41 mg/kg bw/d) based on effects on food consumption being a consequence of reduced appetite observed at the LOEL (Lowest Observed Effect Level) of 150 mg/kg bw/d (actual 132 mg/kg bw/d).


The no observed adverse effect level (NOAEL) for prenatal developmental toxicity is nominal 450 mg/kg bw/d (actual 406 mg/kg bw/d). No adverse fetal findings of toxicological relevance were evident at any dose in this study.

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
450 mg/kg bw/day
Study duration:
subacute
Species:
rabbit
Quality of whole database:
reliable without restrictions
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
8 300 mg/m³
Study duration:
subacute
Experimental exposure time per week (hours/week):
42
Species:
rat
Quality of whole database:
reliable without restrictions
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available
Additional information

Methyl methacrylate has been tested in reliable developmental toxicity studies in rats, rabbits and mice.


 


Inhalation


In a developmental toxicity study according to OECD 414 and conducted in compliance with GLP standards (Solomon et al. 1991), methyl methacrylate (99.9% active ingredient) was administered by inhalation exposure to 5 groups (27 rats/group) of presumed pregnant rats (Crl:CDBR) at concentrations of ca. 0 (control), 0.4, 1.2, 4.8, 8.3 mg/L (corresponding to 99, 304, 1,178, and 2,028 ppm) for 6 hr/day on days 6-15 of gestation (GD) . All doses were administered by a whole-body inhalation exposure under dynamic conditions. Clinical signs were recorded daily on GD 0-20. The dams were weighed on GD 0, 6, 8, 10, 13, 16 and 20. Feed consumption was recorded during gestation. On GD 20, the dams were euthanized and the thoracic and abdominal cavities were examined for gross changes. Each uterus was weighed and corpora lutea, implantation sites and resorptions were counted. Fetuses were weighed, sexed, examined for external alterations and one-half of the fetuses from each litter were examined for visceral alterations.


No treatment-related deaths were noted at any concentration tested. The only clinical sign noted was a minimal increase in the incidence of scant faeces at ca. 8.3 mg/L. At all exposure levels tested losses in maternal body weight or decreases in maternal body weight gain and decreases in maternal feed consumption were noted . Loss in maternal body weight during the first two days of exposure followed by an overall reduced increase in maternal body weight gain during the treatment period was detected for the 4.8 mg/L and 8.3 mg/L groups. Slight effects were observed for the 0.4 and 1.2 mg/L treatment groups as indicated by a transiently (during the first two days of exposure) reduced maternal body weight gain. According to the authors, a maternal no observed effect level (NOEL) could therefore not be demonstrated. No embryo of fetal toxicity was evident and no increase in the incidence in the malformations or variations was noted at exposure levels up to and including 8.3 mg/L. Therefore toxicity to the conceptus was not evident even at exposure levels that resulted in overt maternal toxicity.


Additionally, Tansy et al. (1976) reported no signs of developmental toxicity in a pre-guideline study with mice, which were exposed to ca. 0.48 or 1.64 mg MMA/L (corresponding to 116 and 400 ppm) for 6 hrs/day on GD 4-13.


 


Oral


Methyl Methacrylate was tested for its prenatal developmental toxicity after oral application in Himalayan rabbits according to OECD TG 414 in compliance with GLP (REACH Methacrylate Task Force, 2009). The test substance was administered as an aqueous preparation to 25 inseminated female Himalayan rabbits by stomach tube at doses of 50, 150 and 450 mg/kg body weight/day on GD 6 through GD 28. The control group, consisting of 25 females, was dosed with the vehicle (1% Carboxymethylcellulose CB 30.000 in drinking water and a few drops Cremophor EL and one drop hydrochloric acid [1% CMC]) in parallel. A standard dose volume of 10 mL/kg body weight was used for each test group. At terminal sacrifice on GD 29, 24-25 females per group had implantation sites.


In the mid and high dose group, reduced food consumption (-18% and -13%, resp.) and body weight gain (-31% and -27%, resp.) were noted. No test substance-related adverse effects were observed on gestational parameters or fetuses. In the low dose group, no test substance-related adverse effects on does, gestational parameters or fetuses were observed.


In conclusion, the no observed adverse effect level (NOAEL) for maternal toxicity is 50 mg/kg bw/d. The NOAEL for prenatal developmental toxicity is 450 mg/kg bw/d. No adverse fetal findings of toxicological relevance were evident at any dose.

Toxicity to reproduction: other studies

Additional information

For MMA, based on studies in experimental animals, there is no evidence of selective toxicity to the reproductive system.

Justification for classification or non-classification

In several reliable studies in rats, rabbits and mice, no effects on fertility or developmental toxicity were observed, even in maternal toxic doses. Therefore, methyl methacrylate has not to be classified as developmental toxicant according to 67/548/EEC and UN-GHS requirements, respectively.

Additional information