2-(2-oxoimidazolidin-1-yl)ethyl methacrylate

Endpoint summary

Description of key information

Combined repeated dose study in rats (OECD TG 422), gavage: NOAEL parental toxicity: 100 mg/kg bw/day in males and 300 mg/kg bw/day in females (due to increased organ weights; GLP, Rohm & Haas 2002)

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000-10-23 to 2000-12-19

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

other: Crl:CD BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories (Raleigh Facility, Raleigh, NC)
- Age at study initiation: 11 weeks
- Weight at study initiation: males weighed 357.5 - 358.1 g; and females weighed 240.4 - 241.3 g
- Fasting period before study:
- Housing: Animals were individually housed in stainless steel cages (34 cm x 18 cm x 18 cm) with wire-mesh fronts and bottoms, suspended over pans containing absorbent liners. Cage liners were changed at least three times weekly. During mating, cage liners were changed daily. Clean cage banks were supplied approximately every two weeks. After mating, females were housed in polycarbonate shoe-box cages (53 cm x 29 cm x 20 cm) containing Alpha-Dri bedding (Shepherd Specialty Papers, Irre.) throughout gestation and lactation.
- Diet: During the acclimation and treatment periods, all animals had free access to PMI Certified Rodent Diet #5002M (Ralston Purina Co., St. Louis, MO).
- Water: Water purified by reverse osmosis was available ad libitum via an automatie watering system or water bottles.
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-22
- Humidity (%): 41-63
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

Reverse Osmosis (RO) Water

Details on oral exposure:

Dosage: 5 mL/kg bw
The appropriate amount of test substance was used to prepare sufficient quantities of gavage solutions at concentrations appropriate to deliver dose levels of 100, 300, and 1000 mg ai/kg/dayat a constant volume of 5 mL/kg. The dose levels were adjusted to represent percent active ingredient. The test substance was weighed in a hood and diluted in reverse osmosis (RG) water. Group 1 (control) received RO water only. Gavage solutions were prepared once a week and stored in the refrigerator. Prior to gavaging the animals each day, an aliquot of each concentration was placed in a small beaker and allowed to warm to approximate room temperature. Daily dosing solutions and any treated gavage solution unused at the end of a dosing period were discarded as hazardous waste.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Stability of the test substance in RO water, when stored refrigerated for 8 days, was determined from the first dose preparation. Homogeneity was
determined by analyzing top, middle and bottom sampIes from the first dose preparation. SampIes of dosing solutions prepared on days 34 and 52 were analyzed for active ingredient content to determine proximity to target concentrations.
The sampIes were diluted to 100 ppm with acetonitrile and analyzed by HPLC. Proximity to target for the sampIes analyzed ranged from 89.3% to 100.0%. Day 8 stability of the sampIes was confirmed. Homogeneity analysis was done by performing proximity to target far the top, middle, bottom sampIe and reporting the standard deviation. The standard deviation ranged from 1.19 to 3.39 (n = 3). There were no issues of homogeneity.

Duration of treatment / exposure:

8 weeks

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
0 (control), 100, 300 or 1000 mg a.i. /kg body weight/day
Basis:
actual ingested

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The test substance was administered daily via gavage at dose levels of 0 (control), 100, 300, or 1000 mg a.i./kg of body weight/day (Groups 1, 2, 3, and 4, respectively). The limit dose of 1000 mg a.i./kg bw/day was selected based on agavage range-finding study which induced minimal toxicity in the parameters measured. The low and middle doses were approximately logarithmically spaced from the high dose.
- Rationale for selecting satellite groups: no satellite groups

Positive control:

not required

Observations and examinations performed and frequency:

CLINICAL OBSERVATIONS AND FREQUENCY:
- Clinical signs: During the treatment period, each rat was observed twice daily for morbidity or mortality (except on weekends and holidays, when they were observed once). General clinical observations were made at least once daily,
- Mortality: Rats were euthanized for post-mortem examination if it is anticipated that they would not survive until the next observation period, or for human reasons.
- Body weight: Parental Animals: Body weight was determined weekly for males throughout this study. Females were weighed weekly until cohabitation, on Gestation Days (G) 0, 3, 6, 9, 12, 15, 18, and 20, and on Postnatal Days (PND) 0 and 4.
- Food consumption: Food consumption was determined weekly for male and female animals until cohabitation. Food consumption was not measured for either sex during cohabitation due to the inability to ascribe consumption to individual animals. Females feed consumption was measured from G0-7, G7-14, G14-21 and from PND 0-4 during lactation. The weekly feed consumption was resumed for males after the mating period and continued throughout the study.
- Haematology: Hematology and clinical chemistry measurements were performed on all animals at terminal necropsy. Animals were fasted overnight and blood samples were collected just prior to terminal necropsy. All samples were collected from the abdominal aorta of rats that had been anesthetized with an anesthetic mixture [ketamine HCL (100 mg/ml), xylazine (20 mg/ml), and acepromazine maleate (10 mg/ml) prepared at a 220:10:3 ratio] administered intraperitoneally at approximately 0.1 ml/150 g body weight to effect. Blood samples were collected in an order that rotated through treatment groups (i.e., one animal from each treatment group was bled before a second animal from the same group.) Once blood was collected, animals were exsanguinated via the abdominal aorta. Necropsy and blood sample collection were performed over two consecutive days (approximately 6 animals/sex/group were necropsied each day). The following hematology and clinical chemistry parameters were measured on each sample:
Hematology
a. Erythrocytes (RBC); b. Hematocrit (HCT); c. Hemoglobin (HGB); d. Mean Cell Hemoglobin (MCH); e. Mean Cell Hemoglobin Concentration (MCHC);
f. Mean Cell Volume (MCV); g. Platelets (PLT); h. Total White Blood Cell Count (WBC) and Differential (WBC DIFF)
Clinical Chemistry
a. Alanine aminotransferase (ALT); b. Albumin (ALB); c. Albumin/globulin ratio (A/G); d. Alkaline Phosphatase (ALP); e. Aspartate aminotransferase (AST); f. Blood Urea Nitrogen (BUN); g. Calcium (CA); h. Chloride (CL); i. Creatinine (CREA); j. Gamma Glutamyltransferase (GGT); k. Globulin (GLOB); l. Glucose (GLU); m. Inorganic Phosporus (PHOS); Clotting Potential; n. Potassium (K); o. Sodium (NA) Prothrombin time (PT); q. Total Cholesterol (CHOL); r. Total Protein (TP); s. Triglycerides (TRIG)

Sacrifice and pathology:

ORGANS EXAMINED AT NECROPSY (MACROSCOPIC AND MICROSCOPIC):
- Organ weights: Organ weights (absolute and relative to body weight) obtained for all parental animals were: adrenals, brain, heart, kidneys, liver, spleen and thymus. For the males weights were obtained for testes and epididymides.
- Histopathology P and F1: Microscopic examination of the organs listed below were performed for 5 (randomly selected) parental animals/sex in the high dose group and control group, and in the Group 3 female humanely sacrificed during the course of this study. All tissues exhibiting gross pathological changes were examined microscopically. Cecum was examined from 5 randomly selected females from each group. All tissues exhibiting gross pathological changes were examined microscopically.
Adrenals (2); lungs (inflate with fixative); bone marrow smear (femur); bone, sternum (with marrow); lymph nodes (mandibular/cervical and mesenteric); brain (medulla/pons, nerve, peripheral (sciatic); cerebellum, cerebrum); cervix; ovaries (2); prostate; coagulating glands (2); seminal vesicles;
epididymides (2); spinal cord; esophagus; spleen; gross lesions; heart; stomach (forestomach & glandular portions); intestine (including Peyer's patches); testes (2); duodenum; cecum; trachea; jejunum; colon thymus; ileum; rectum; thyroid (2); kidneys (2); urinary bladder; liver; uterus; vagina

Other examinations:

none

Statistics:

The litter (i.e., proportion of pups/litter, or litter mean) was used, where appropriate, as the experimental unit for the purpose of statistical evaluation. The level of statistical significance selected was p<0.05, unless otherwise noted. The statistical tests that were used to analyze the parameters studied are listed below:
- Analysis of Variance (ANOVA)
- 2xN Chi-square test
- 2xN Kruskal-Wallis nonparametric ANOVA
- Dunnett's test
- Fisher's exact test

Details on results:

TOXIC RESPONSE/EFFECTS BY DOSE LEVEL:
- Mortality and time to death: There were no treatment-related deaths were noted in female parental animals during premating, gestation or lactation, in pups during lactation, or in males throughout the study at dose levels up to including 1000 mg a.i./kg bw/day. One male at 0 mg/kg and one female at 300 mg/kg were euthanized in a moribund condition. These deaths were not considered treatment-related but due to dosing error. Microscopic evaluation confirmed inadvertent dosing trauma.

- Clinical signs: No treatment-related effects were seen in the Detailed Clinical Observations or Functional Observational Battery parameters. There were no treatment-related effects noted in motor activity in either sex up to and including 1000 mg a.i./kg bw/d.

- Body weight gain: There were no treatment-related effects on body weight or feed consumption in females during the premating, gestation or lactation periods or in males throughout the study at dose levels up to and including 1000 mg a.i./kg bw/d.

- Food/water consumption: There were no treatment-related effects on feed consumption in females during the premating, gestation or lactation periods or in males throughout the study.

- Ophthalmoscopic examination: Not described.

- Clinical chemistry: No treatment-related effects on any clinical chemistry parameters were observed in male or female animals at any dose level up to and including 1000 mg a.i./kg bw/d. A statistically significant decrease in the cholesterol (males) and an increase in phosphorus (females)
was noted at 1000 mg a.i./kg bw/d. These changes were considered incidental and not treatment-related. Statistically significant decreases in triglyceride values in females at 100 and 300 mg a.i./kg bw/d were not considered treatment-related since there was no dose response.

- Haematology: No treatment-related effects on hematology parameters or white blood cell counts (total or differential) were observed in females at any dose level or in males up to and including 300 mg.a.i./kg bw/d. Treatment-related decreases in hemoglobin (6%), hematocrit (7%), and mean cell volume (4%) were noted in males at 1000 mg a.i./kg bw/d. In addition, platelet counts were increased (14%) at this level. Statistically significant decreases in mean cell volume and cell hemoglobin noted in females at 300 mg/kg a.i./kg bw/d were considered incidental since similar effects were seen at the higher doses.

- Organ weights: There were no treatment-related effects on absolute or relative organ weights in females at concentrations up to and including 300 mg a.i./kg bw/d or in males at 100 mg a.i./kg bw/d. Treatment-related increases in absolute and relative kidney weights (10-11%) and in absolute and relative liver weights (20%) were noted in both sexes at 1000 mg a.i./kg bw/d. Absolute and relative liver weights were also increased (12-16%) in males at 300 mg a.i./kg bw/d. A statistically significant decrease in absolute epididymus weight in males at 1000 mg a.i./kg bw/d was considered incidental and not treatment-related. There was not a statistically significant change in relative epididymus weight and there were no corresponding histopathologic findings in the epididymus or in the prostrate or testes. In addition, there were no adverse reproductive effects noted at this level. Statistically significant decreases in absolute and relative testes weights at 300 mg a.i./kg bw/d, and an increase in relative spleen weight in females at 100 mg a.i./kg bw/d were considered incidental since similar effects were not seen at higher levels.

- Gross pathology: Parental Animals: There were no treatment-related gross findings in parental animals of either sex at any dose level.

- Histopathology: There were no treatment-related microscopic changes observed in any male or female rats given 1000 mg a.i./kg/day of Monomer QM-1458 orally by gavage. Microscopic examination of the organs listed below were performed for 5 (randomly selected) parental animals/sex in the high dose group and control group, and in the Group 3 female humanely sacrificed during the course of this study. All tissues exhibiting gross pathological changes were examined microscopically: adrenals (2); bone marrow smear (femur); bone, sternum (with marrow); brain (medulla/pons, cerebellum, cerebrum); cervix; coagulating glands (2); epididymides (2); esophagus; gross lesions; heart; intestine (including Peyer's patches) (duodenum, cecum, jejunum, colon, ileum, rectum); kidneys (2); liver; lungs (inflate with fixative); lymph nodes (mandibular/cervical and mesenteric); nerve, peripheral (sciatic); ovaries (2); prostate; seminal vesicles; spinal cord; spleen; stomach (forestomach & glandular portions); testes; trachea; thymus; thyroid (2); urinary bladder; uterus; and vagina.

Dose descriptor:

NOAEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: increased liver weights

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: increased liver and kidney weights

Critical effects observed:

not specified

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

GLP and guideline study.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The toxicity of ureido methacrylate after repeated oral dosing was assessed by a subacute study which was performed with rats for 8 weeks.

Oral:

The possible toxic effects, including potential neurotoxicity, of the test substance, ureido methacrylate (purity unknown), were evaluated in a GLP conform combined repeated dose study with a Reproduction/ Developmental screening test in rats following OECD test guideline 407 (Rohm & Haas 2002). The test substance was administered orally by gavage to four groups of 12 male and 12 female Crl:CD BR rats once daily for eight weeks. Dose levels were 0, 100, 300, and 1000 mg a.i./kg bw/day, administered at a dosage volume of 5 mL/kg. The control group received the vehicle, double-distilled water, on a comparable regimen at a dosage volume of 5 ml/kg. Males and females of the same treatment group were mated 1:1 two weeks after the beginning of the treatment.

During the treatment period, each rat was observed twice daily for morbidity or mortality. General clinical observations were made at least once daily. Body weight was determined weekly for males throughout this study. Females were weighed weekly until cohabitation, on Gestation Days (G) 0, 3, 6, 9, 12, 15, 18, and 20, and on Postnatal Days (PND) 0 and 4. Food consumption was determined weekly for male and female animals until cohabitation. Food consumption was not measured for either sex during cohabitation due to the inability to ascribe consumption to individual animals. Females feed consumption was measured from G0-7, G7-14, G14-21 and from PND 0-4 during lactation. The weekly feed consumption was resumed for males after the mating period and continued throughout the study. Functional Observational Battery (FOB) and motor activity evaluations were performed on week 5 (males) and week 7 (females). After eight weeks, overnight fasted animals were euthanized and necropsied. Hematology and clinical chemistry measurements were performed on all animals at terminal necropsy. Animals were fasted overnight and blood samples were collected just prior to terminal necropsy. Microscopic examination of the studied organs were performed for 5 (randomly selected) parental animals/sex in the high dose group and control group. All tissues exhibiting gross pathological changes were examined microscopically.

Treatment-related decreases in hemoglobin (6%), hematocrit (7%), and mean cell volume (4%) were noted in males at 1000 mg a.i./kg bw/day. In addition, platelet counts were increased (14%) at this level. Treatment-related increases in absolute and relative kidney weights (10-11%) and in absolute and relative liver weights (20%) were noted in both sexes at 1000 mg a.i./kg. Absolute and relative liver weights were also increased (12-16%) in males at 300 mg a.i./kg. Other effects were considered as incidental and not treatment-related. Microscopic examinations in the relevant organs revealed no complementary effects seen in liver and kidney weights, these observations are considered as not adverse.

Based on the results of this study, the NOAEL (no-observed-effect level) for systemic toxicity of ureido methacrylate administered orally is 100 mg a.i./ kg bw/day in males and 300 mg a.i./ kg bw/day in females.

Additionally, data were adopted by read-across from a reliable chronic 2-year toxicity study of methyl methacrylate (CAS 82-60-6) in rats and from a two-generation reporduction toxicity study (see IUCLID section 7.8) in rats. Due to the structural similarities, the comparable results can be expected for ureido methacrylate. In addition, 3 subacute studies with methyl methacrylate are reported.

Twenty-five male and female Wistar rats (P parental generation) were administered with MMA at 0; 50; 150 and 400 mg/kg body weight/day in an OECD 416 2 generation reproductive toxicity study (BASF, 2009). 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. No signs of systemic toxicity were observed other than slightly reduced body-weight gain at 150 mg/kg bw/d and above in the 2-gen study. Reduced body weights were judged to be the direct result of reduced food intake and therefore not an adverse finding. Consequently, the NOAEL was confirmed at the highest dose studied (450 mg/kg/d).

Twenty-five male and female Wistar rats were administered three doses of methyl methacrylate in the drinking water for two years (Borzelleca et al. 1964). Initial doses of 6, 60 or 2000 ppm were partially raised to 7, 70 and 2000 ppm after 5 months.

A special design was employed to reduce the volatilization and measurements which showed that the methyl methacrylate concentrations remained within 15% of the nominal concentration for 72 hours. Body weight depression was also observed at 2000 ppm but it did not persist beyond the first few weeks of the study. Significant depression of fluid consumption was observed at 2000 ppm, although this tended to regress at the end of the study. Individual observations of depressed food consumption tended to parallel periods of depressed growth. There were significantly increased kidney ratios for female rats at 2000 ppm. These effects were believed to be a consequence of reduced food intake and reduced body weights, and in the absence of any histopathology, were considered as not biologically relevant. Therefore the NOAEL is considered to be >= 2000 ppm, corresponding to 124.1 mg/kg bw/day and 164 mg/kg bw/day, for males and females, respectively, on the basis of treatment specific fluid consumption rates and body weights.

In 3 subacute toxicity studies, results comparable to the findings of the chronic 2 year study with methyl methacrylate were observed. Edward (1975) reported a NOAEL of >18800 ppm in rats after 5 weeks oral administration. Husain (1985) and Ghanayem (1986) both showed a NOAEL of 200 mg/kg bw/day after 28 d respectively 14 days oral exposure of rats.

Conclusion for hazard assessment:

Data from read across with methyl methacrylate show a NOAEL of 124.1 mg/kg bw/day (chronic exposure) and of about 200 mg/kg bw/day after subacute exposure in rats. The NOAEL of a subacute study (OECD 422) with ureido metharcrylate was found to be 100 mg/kg bw/day. Due to the structural similarities of both methacrylates a similar mode of action can be assumed. Thus, data from both methacrylates show comparable NOAELs after chronic and subacute exposure. Thus, for ureido methacrylate also a NOAEL in the range of the subacute study is expected also after longer subchronic exposure. In conclusion, DNELs are derived from the subacute study with ureido methacrylate applying a factor of 6 for extrapolation from subacute to chronic which is believed to be a worst case assumption. No further subchronic testing with allyl methacrylate is needed for animal welfare reasons.

Inhalation:

In accordance with column 2 of REACH Annex IX, the test repeated dose toxicity after inhalation (required in section 8.6) does not need to be conducted as a repeated dose toxicity study for oral (28 days, OECD 422) application is available. In addition read across to subchronic oral studies with methyl methacrylate was done.

Dermal:

In accordance with column 2 of REACH Annex IX, the test repeated dose dermal toxicity (required in section 8.6) does not need to be conducted as a repeated dose toxicity study for oral (28 days, OECD 422) application is available. In addition read across to subchronic oral studies with methyl methacrylate was done.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
The most reliable study was selected. Study was conducted in compliance with OECD guideline and GLP regulation.

Justification for classification or non-classification

Based on the results obtained, there is no indication given for classification regarding repeated dose toxicity according to 67/548/EEC and Regulation (EC) No 1272/2008 (GHS, CLP).