[No public or meaningful name is available]

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 03 june 2016 to 21 april 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

Temporary deviations from the daily mean relative humidity occurred

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of N-[2-(2-oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid

IUPAC Name:

Reaction mass of N-[2-(2-oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid

Test material form:

liquid

Details on test material:

- Name of test material (as cited in study report): Reaction mass of N-[2-(2-Oxoimidazolidin-1-yl)ethyl] methacrylamide and methacrylic acid, other name: Sipomer wam II
- Storage condition of test material: at room temperature

Specific details on test material used for the study:

Purity/composition correction factor : Yes, correction factor is 1.39 based on purity
Test item handling: No specific handling conditions required
Stability at higher temperatures: Not available
Chemical name (IUPAC), synonym or trade name: Reaction mass of N-[2-(2-oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid ; SIPOMER WAM II
CAS Number: Not indicated. EC number: 934-058-1, used for registration
Molecular structure: Not indicated
Molecular formula: Not indicated
Molecular weight: 119 (The molecular weight is given as a mean value of the molecular weight of the components and additives of the reaction mass, based on the typical concentrations measured on a sample of the multiconstituant substance)
Irritant or corrosive: Yes, severely irritant to the eyes
pH: 2-5 at concentration of 10%
Specific gravity/density: 1.1086 (relative density at 20°C)
Solubility in vehicle:
• Water: 999 g/L
Stability in vehicle:
• Water: Stability for at least 1 day at room temperature, 8 days in the refrigerator and 3 weeks in the freezer is confirmed over the concentration range 1 to 200 mg/g, Test Facility Study No. 512223

Test animals

Species:

rat

Strain:

other: Crl:WI (Han)

Details on test animals or test system and environmental conditions:

- Number: F0-generation: 88 females. F1-generation: 886 fetuses.
- Strain and sanitary status: Rat: Crl:WI(Han) (outbred, SPF-Quality).
- Breeder: Charles River Deutschland, Sulzfeld, Germany.
- Age/Weight: Females were approximately 10-14 weeks.
- Housing: Females were individually housed in Macrolon plastic cages (MIII type, height 18 cm). Sterilized sawdust as bedding material (Lignocel S 8-15, JRS - J.Rettenmaier & Söhne GmbH + CO. KG, Rosenberg, Germany) and paper as cageenrichment/ nesting material (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom) were supplied.
- Food and water: Diet : Free access to pelleted rodent diet (SM R/M-Z from SSNIFF®Spezialdiäten GmbH, Soest, Germany). Water: Free access to tap-water.
- Acclimation: At least 5 days prior to treatment.
- Allocation to study:

Group Dose level * (mg/kg) Number of females Animal numbers
1 0 22 1-22
2 50 22 23-44
3 150 22 45-66
4 500 22 67-88

- Identification: By indelible ink.

ENVIRONMENTAL CONDITIONS
- temperature: 18 to 24°C,
- relative humidity: 40 to 70%,
- light/dark cycle: 12h/12h,
- ventilation: at least 10 air changes/hour

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

Dose formulation preparation
Formulations (w/w) were prepared daily within 6 hours prior to dosing and were homogenized to a visually acceptable level. No adjustment was made for specific gravity/density of the vehicle. Adjustment was made for specific gravity of the test item
(1.1086). A correction was made for the purity/composition of the test item. A correction factor of 1.39 was used.
Appearance of formulations: Solution (Groups 2-4).
Storage conditions: At room temperature.
Formulations were placed on a magnetic stirrer during dosing.

VEHICLE
- Lot/batch no. (if required): water (Elix, Millipore S.A.S., Molsheim, France)

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses were conducted on a single occasion during the treatment phase (25 July 2016), according to a validated method (Test Facility Study No. 512223). Samples of formulations were analyzed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations).
The accuracy of preparation was considered acceptable if the mean measured concentrations were 90-110% of the target concentration. Homogeneity was demonstrated if the coefficient of variation was ≤ 10%.

Details on mating procedure:

- Mating: Untreated females were mated at the Supplier, and were at Day 0 or 1 post-coitum on arrival at the Test Facility (Day 0 post-coitum was the day of successful mating; confirmed by vaginal plug).

Duration of treatment / exposure:

From Days 6 to 20 post-coitum, inclusive.

Frequency of treatment:

Once daily for 7 days per week, approximately the same time each day with a maximum of 6 hours of difference between the earliest and latest dose.

Duration of test:

Two months and a half

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

50 mg/kg bw/day

Doses / concentrations 2

Dose / conc.:

150 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

500 mg/kg bw/day

No. of animals per sex per dose:

22 mated female per group

Control animals:

yes, concurrent vehicle

Details on study design:

Rationale for dose-level selection
Dose levels were selected based on results of the dose range finding study (Test Facility Study No.512216), in which dose levels of 100, 300 and 1000 mg/kg were tested. Three out of six females at 1000 mg/kg were killed in extremis on Day 11 post-coitum, as they showed lethargy, hunched posture and piloerection. Moreover, rales were noted for one female given 1000 mg/kg. Body weight loss (12 to 14%) was noted for these females on Day 9 post-coitum and food consumption was slightly reduced on Days 6-9 post-coitum. At necropsy, dark red foci on the glandular mucosa of the stomach was noted for one female given 1000 mg/kg. The remaining three females at 1000 mg/kg showed rales (2/3), food consumption was slightly reduced on Days 6-15 post-coitum and lower gravid uterus corrected body weight gain were noted. No toxicologically relevant effects were observed at 100 and 300 mg/kg.

Examinations

Maternal examinations:

Mortality / Viability:
At least twice daily.

Clinical signs:
At least once daily from Day 2 post-coitum onwards up to the day prior to necropsy. The time of onset, grade and duration of any observed signs were recorded. Signs were graded for severity and the maximum grade was predefined at 3 or 4. Grades were coded as slight (grade 1), moderate (grade 2), severe (grade 3) and very severe (grade 4). For certain signs, only its presence (grade 1) or absence (grade 0) was scored. In the data tables, the scored grades were reported, as well as the percentage of animals affected in summary tables.

Body weights:
Days 2, 6, 9, 12, 15, 18 and 21 post-coitum.

Food consumption:
Days 2-6, 6-9, 9-12, 12-15, 15-18 and 18-21 post-coitum.

Water consumption:
Subjective appraisal was maintained during the study, but no quantitative investigation was introduced as no treatmentrelated effect was suspected.


POST-MORTEM EXAMINATIONS:
- All animals were sacrificed on Day 21 post-coitum using an oxygen/carbon dioxide procedure and subsequently subjected to an external, thoracic and abdominal examination, with special attention being paid to the reproductive organs.
- All macroscopic abnormalities were recorded, collected and fixed in 10% buffered formalin (neutral phosphate buffered 4% formaldehyde solution, Klinipath, Duiven, The Netherlands).
- Each ovary and uterine horn of all animals was dissected and examined as quickly as possible.

Ovaries and uterine content:

The ovaries and uterus of the females were examined to determine:
• The number of corpora lutea.
• The weight of the (gravid) uterus.
• The number and distribution of live and dead fetuses.
• The number and distribution of embryo-fetal deaths (early and late resorptions).
• The weight of each fetus.
• The sex of each fetus from the ano-genital distance (during necropsy) and also from gonadal inspections (during further fetal examination).
• Externally visible macroscopic fetal abnormalities.

The following definitions were applicable for implantation data:
• Fetal (late) resorptions were defined as a dead fetus with external degenerative changes and presence of distinguishable features such as head or limbs.
• Embryonic (early) resorptions were defined as evidence of implantation without presence of distinguishable features such as head or limbs.
• Dead fetus was defined as a non-viable fetus without external degenerative changes and presence of distinguishable features such as head or limbs.
• Post-implantation loss included embryonic (early) resorptions, fetal (late) resorptions and dead fetuses.

In case implantations were not macroscopically visible, the uterus was stained using the Salewski technique in order to determine any former implantation sites (Salewski staining prepared at Charles River Den Bosch using Ammoniumsulfide-solution 20% (Merck, Darmstadt, Germany) and Milli-Ro water (Millipore Corporation, Bedford, USA)).

Fetal examinations:

External, visceral, and skeletal findings were recorded as developmental variations (alterations in anatomic structure that are considered to have no significant biological effect on animal health or body conformity and/or represent slight deviations from normal) or malformations (those structural anomalies that alter general body conformity, disrupt or interfere with normal body function, or may be incompatible with life).

External examination
Each viable fetus was examined in detail, weighed and sexed. All live fetuses were euthanized by administration of approximately 0.05 mL (=10mg) of sodium pentobarbital (Euthasol® 20%; AST Farma B.V., Oudewater) into the oral cavity using a small flexible plastic or metal feeding tube. Nonviable fetuses (for which the degree of autolysis was minimal or absent) were examined and weighed. For late resorption A079-009, a gross external examination was performed. As no malformation was observed, this late resorption together with the early resorptions were discarded.

Visceral (Internal) examination
Approximately one-half of the fetuses (live and dead) in each litter (all groups) were examined for visceral anomalies by dissection in the fresh (non-fixed) state. The thoracic and abdominal cavities were opened and dissected using a technique described by Stuckhardt and Poppe. This examination included the heart and major vessels. Fetal kidneys were examined and graded for renal papillae development as described by Woo and Hoar. The sex of all fetuses was confirmed by internal examination.
As prominent visceral malformations were noted for two fetuses (A049-03 and A069-05), selected for skeletal examination, additional visceral examination of these fetuses was performed. The heads were removed from approximately one-half of the fetuses in each litter and placed in Bouin's solution (Klinipath, Duiven, The Netherlands) for soft-tissue examination of all groups using the Wilson sectioning technique. Any remaining tissues (from the fetuses used for fresh visceral examination) were discarded. The carcasses were processed and stained with Alizarin Red S (as described below), but not examined in first instance.

Skeletal examination
From the other one-half of the fetuses (live and dead) in each litter (all groups), the sex was confirmed by internal examination. All fetuses were eviscerated, fixed in 96% aqueous ethanol, macerated in potassium hydroxide (Merck, Darmstadt, Germany) and stained with Alizarin Red S (Klinipath, Duiven, The Netherlands) by a method similar to that described by Dawson. Skeletal examination was done for one-half of the fetuses (i.e. the fetuses with heads). The specimens were archived in glycerin (BRENNTAG Nederland B.V., Dordrecht, The Netherlands) with bronopol (Alfa Aesar, Karlsruhe, Germany) as preservative. A few bones were not available for skeletal examination because they were accidentally damaged or lost during processing. The missing bones were listed in the raw data; evaluation by the fetal pathologist and study director determined that there was no influence on the outcome of the individual or overall skeletal examinations, or on the integrity of the study as a whole.

Statistics:

The following statistical methods will be used to analyze the data:
- If the variables can be assumed to follow a normal distribution, the Dunnett-test (many-to-one t-test) based on a pooled variance estimate will be applied for the comparison of the treated groups and the control groups for each sex.
- The Steel-test (many-to-one rank test) will be applied if the data cannot be assumed to follow a normal distribution.
- The Fisher Exact-test will be applied to frequency data.
- The Mann Whitney test will be used to compare mean litter proportions (percent of litter) of the number of viable and dead fetuses, early and late resorptions, total resorptions, pre- and post-implantation loss, and sex distribution.
- Mean litter proportions (percent per litter) of total fetal malformations and developmental variations (external, visceral and skeletal), and each particular external, visceral and skeletal malformation or variation will be subjected to the Kruskal-Wallis nonparametric ANOVA test to determine intergroup differences. If the ANOVA reveals statistically significant (p<0.05) intergroup variance, Dunn’s test will be used to compare the compound-treated groups to the control group.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Rales were noted for seven females at 500 mg/kg for 1 to 11 days at a slight to moderate degree. Piloerection and hunched posture, in addition to rales, were noted for single females at 500 mg/kg (no. 70 and 76, respectively) on one single day. As these signs were observed in the high dose group only, these were considered to be treatment-related. Incidental findings that were noted included alopecia and diarrhoea. These findings occurred within the range of background findings to be expected for rats of this age and strain which are housed and treated under the conditions in this study. At the incidence observed, these were considered signs of no toxicological relevance.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

No unscheduled mortality occurred.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

Mean body weights and body weight gains of animals treated up to 500 mg/kg remained in the same range as controls. One female at 500 mg/kg (no. 76) showed significantly lower body weights and body weight gain over the entire treatment period, when compared to the other females in the 500 mg/kg group. This female had a body weight loss of 11% from Day 6 to 9 post-coitum. The days after, body weight was slightly increased. Over the entire treatment period, i.e. from Day 6 to
20 post-coitum, a body weight loss of 4% was noted for this female. As only one out of twenty-two females of the 500 mg/kg group was affected, this was not considered to be toxicologically relevant.
Weight gain corrected for gravid uterus was slightly lower in the treated groups, compared to controls. The mean corrected weight gain was 28.5, 22.7, 23.6 and 21.7 gram in respectively the control, 50, 150 and 500 mg/kg groups. This decrease reached statistical significance at 500 mg/kg. As the changes in all treatment groups were only slight, within the range considered normal for rats of this age and strain and without a dose-response, they were not considered to be toxicologically relevant.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

No toxicologically relevant changes in mean food consumption before and after correction for body weight were noted up to 500 mg/kg. The trend towards slightly reduced food consumption before and after correction for body weight in the treated groups compared to controls was not considered to be toxicologically relevant. The reduction was only slight, no dose-response relationship was observed and the values remained within the range considered to be normal for rats of this age and strain. Moreover, the statistically significantly lower relative food consumption at 150 mg/kg on Days 12 to 15 post-coitum was not considered to be toxicologically relevant as the change was only slight and without dose-response.
Female no. 76 had a significantly lower food intake over the entire treatment period when compared to the other females of the 500 mg/kg group, which was the cause of the significantly lower body weight gain of this female.

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

Other effects:

no effects observed

Description (incidence and severity):

Macroscopic Examination:
One female at 500 mg/kg (no. 76) was emaciated and showed a thymus reduced in size. Moreover, the jejunum, ileum, caecum and colon of this female were distended with gas. These findings were related to the observations during the in-life phase, i.e. rales, hunched posture and significant lower body weight and food consumption (see previous sections). Alopecia was noted in the control, 50 and 500 mg/kg group for single females, confirming the clinical sign observed during the in-life phase. At the incidence observed, this was not considered to be treatment-related.

Details on results:

Treatment up to 500 mg/kg resulted in significant lower body weight and food consumption of one single female given the high dose. This female showed rales and hunched posture during the in-life phase, and was emaciated and showed a thymus reduced in size at necropsy. Moreover, its jejunum, ileum, caecum and colon were distended with gas. For the remaining females treated at 500 mg/kg, no toxicologically relevant changes in body weight and food consumption were noted and no treatment-related clinical signs or macroscopic findings were observed. As only one out of twenty-two females in the 500 mg/kg group was affected, this was not considered to be toxicologically relevant.
No maternal toxicity was observed in the 50 and 150 mg/kg groups.

Maternal developmental toxicity

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

no effects observed

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed

Changes in number of pregnant:

no effects observed

Other effects:

no effects observed

Details on maternal toxic effects:

Maternal Pregnancy Data:
Three females in the 500 mg/kg group (nos. 80, 83 and 88) were not pregnant. This was not considered to be treatment-related as treatment started from implantation onwards (i.e. Day 6 post-coitum). All other females were pregnant and had litters with viable fetuses. The lower number of pregnant females in Group 4 did not affect the evaluation as there were sufficient litters available for a proper toxicological evaluation. The numbers of pregnant females, corpora lutea and implantation sites, and pre-implantation loss in the control and test groups were similar and in the range of normal biological variation.

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Remarks:

maternal toxicity

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: no relevant effects

Results (fetuses)

Fetal body weight changes:

no effects observed

Description (incidence and severity):

There were no effects on mean fetal body weights (both sexes) noted up to 500 mg/kg. Female no. 76 had 10 fetuses which had significant lower fetal body weights. The mean fetal body weight of this litter was 3.4 gram, compared to a mean value of 5.3 gram for Group 4. As the remaining litters of Group 4 had normal fetal weights, this was considered related to the maternal observations of this single dam during the in-life phase, i.e. rales, hunched posture and significant lower body weight and food consumption. Mean combined (male and female) fetal body weights were 5.2, 5.3, 5.2 and 5.3 gram for the control, 50, 150 and 500 mg/kg groups, respectively.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Description (incidence and severity):

The male:female ratio was unaffected by treatment up to 500 mg/kg. Mean sex ratios (males:females) were 48:52, 52: 48, 50:50 and 58:42 for the control, 50, 150 and 500 mg/kg groups, respectively.

Changes in litter size and weights:

no effects observed

Description (incidence and severity):

There were no effects on litter size of any group. Mean litter sizes were 10.0, 10.8, 10.7 and 10.2 viable fetuses/litter for the control, 50, 150 and 500 mg/kg groups, respectively.

Changes in postnatal survival:

no effects observed

External malformations:

no effects observed

Description (incidence and severity):

There were no treatment-related effects on external morphology following treatment up to 500 mg/kg. The only external malformation that occurred in this study was observed in Group 3 fetus A049-03. This fetus had a small lower jaw and was found to be missing an eye. At subsequent skeletal examination, both malformations were confirmed, but as these occurred singly, they were considered to be chance findings. External variations were not seen in any group.

Skeletal malformations:

no effects observed

Description (incidence and severity):

There were no treatment-related effects on skeletal morphology following treatment up to 500 mg/kg. The only skeletal malformation (a bent scapula) in this study was noted in control fetus A021- 03 and as such was considered a chance finding.
Skeletal variations occurred at an incidence of 76.3%, 89.0%, 76.6% and 74.9% per litter in Groups 1, 2, 3 and 4, respectively. Noteworthy is the variation of bent ribs for which the incidence in Group 4 was statistically significantly lower than the control value. Mean litter incidences of this finding were 17.9%, 15.6%, 11.2% and 3.9% per litter in Groups 1, 2, 3 and 4, respectively. As all values were within the historical control data range (0.8% - 22.3% per litter) and as a decreased incidence of this finding is not an adverse effect, this lower value in Group 4 was not considered to be toxicologically relevant.
Other skeletal variations that were noted in this study occurred at low incidences, in the absence of a dose-related incidence trend and/or at frequencies that were within the range of available historical control data, and were therefore not considered to be toxicologically relevant.

Visceral malformations:

no effects observed

Description (incidence and severity):

There were no treatment-related effects on visceral morphology following treatment up to 500 mg/kg. Visceral malformations were observed in respectively 1, 1, 1 and 2 fetuses in Groups 1, 2, 3 and 4. The two affected fetuses of Group 4 were from the same litter (i.e. fetuses A069-02 and -05) and both had a right-sided aortic arch. Hence, the origin was considered to be likely genetic rather than toxicological. The other affected fetuses were the Group 3 fetus (A049-03) with an absent eye and Group 1 and 2 fetuses A014-03 and A028-05, respectively, of which all organs were laterally transposed. Due to the single occurrence and/or occurrence in a control fetus only, these were considered to be chance findings. The visceral variations that were noted in this study occurred singly or at low incidences in the absence of a dose-related incidence trend and therefore were not considered to be treatment-related.

Other effects:

no effects observed

Details on embryotoxic / teratogenic effects:

The significantly lower fetal body weights of one single litter at 500 mg/kg were considered related to the maternal observations of this single dam during the in-life phase rather than a developmental cause. No developmental toxicity was observed in the 50, 150 and 500 mg/kg groups.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Remarks:

Development

Effect level:

500 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: no relvant effects

Fetal abnormalities

Abnormalities:

no effects observed

Overall developmental toxicity

Developmental effects observed:

no

Any other information on results incl. tables

see attached document

Applicant's summary and conclusion

Conclusions:

Based on the results in this prenatal developmental toxicity study the maternal and developmental No Observed Adverse Effect Level (NOAEL) for Reaction Mass of n-[2-(2- oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was established as being at least 500 mg/kg.

Executive summary:

The objective of this prenatal development toxicity study (2017) was to evaluate the potential toxic effects of the test item, Reaction Mass of n-[2-(2-oxoimidazolidin-1- yl)ethyl]methacrylamide and methacrylic acid, in rats by oral gavage according to the OECD guideline n° 414.

 

Eighty-eight mated female Wistar Han rats were assigned to four dose groups. The test item was administered once daily by oral gavage from Days 6 to 20 post-coitum at doses of 50, 150 and 500 mg/kg (Groups 2, 3 and 4 respectively). The high dose of 500 mg/kg was considered to be the highest feasible dose in this type of study as treatment-related mortality was observed at 1000 mg/kg for half of the females in the dose range finding study. The rats of the control group received the vehicle, water, alone. Females were checked daily for the presence of clinical signs. Food consumption and body weight were determined at periodic intervals. Formulations prepared on one day during treatment were analyzed for accuracy and homogeneity. All animals surviving to Day 21 post-coitum were subjected to an examinationpost-mortemand external, thoracic and abdominal macroscopic findings were recorded. Gross lesions were collected and fixed from all animals at necropsy. A laparohysterectomy was performed on each surviving female of the groups. The uteri, placentae and ovaries were examined, and the numbers of fetuses, early and late resorptions, total implantations and corpora lutea were recorded. Gravid uterine weights were recorded, and corrected body weights (changes) were calculated. The fetuses were weighed, sexed and examined for external, visceral and skeletal malformations and developmental variations. All live fetuses were euthanized.One half of the fetuses were decapitated and the heads were fixed in Bouin’s fixative; these fetuses were dissected and examined for visceral anomalies. The other one-half of the fetuses were processed and stained with Alizarin Red S for skeletal examinations.

 

Maternal findings

Treatment up to 500 mg/kg resulted in significant lower body weight and food consumption of one single female given the high dose. This female showed rales and hunched posture during the in-life phase, and was emaciated and showed a thymus reduced in size at necropsy. Moreover, its jejunum, ileum, caecum and colon were distended with gas. For the remaining females treated at 500 mg/kg, no toxicologically relevant changes in body weight and food consumption were noted and no treatment-related clinical signs or macroscopic findings were observed. As only one out of twenty-two females in the 500 mg/kg group was affected, this was not considered to be toxicologically relevant. No maternal toxicity was observed in the 50 and 150 mg/kg groups.

 

Developmental findings

The significantly lower fetal body weights of one single litter at 500 mg/kg were considered related to the maternal observations of this single dam during the in-life phase rather than a developmental cause. No developmental toxicity was observed in the 50, 150 and 500 mg/kg groups.

 

Based on the results in this prenatal developmental toxicity study the maternal and developmental No Observed Adverse Effect Level (NOAEL) for Reaction Mass of n-[2-(2- oxoimidazolidin-1-yl)ethyl]methacrylamide and methacrylic acid was established as being at least 500 mg/kg.