N,N''-methylenebis[N'-[3-(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]urea]

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Adequately reported study performed using a standard test method: includes sufficient information to permit evaluation of developmental toxicity.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1973

Report date:

1973

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

EPA OPP 83-3 (Prenatal Developmental Toxicity Study)

GLP compliance:

no

Remarks:

Pre-GLP study

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

N,N''-methylenebis[N'-[3-(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]urea]

EC Number:

254-372-6

EC Name:

N,N''-methylenebis[N'-[3-(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]urea]

Cas Number:

39236-46-9

Molecular formula:

C11H16N8O8

IUPAC Name:

N',N'''-methylenebis{1-[3-(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]urea}

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Fine whte powder

Test animals

Species:

mouse

Strain:

CD-1

Details on test animals or test system and environmental conditions:

Virgin adult females

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

Daily oral administration during the dosing period.

Analytical verification of doses or concentrations:

no

Details on mating procedure:

Mated with young adult male mice: observation of vaginal sperm plug confirmed mating and was designated Day 0 of gestation.

Duration of treatment / exposure:

10 days (gestation Days 6-15)

Frequency of treatment:

Once daily

Duration of test:

Females terminated on gestation Day 17.

Doses / concentrations

Remarks:

Doses / Concentrations:
30, 95, 300 mg/kg/day
Basis:
actual ingested

No. of animals per sex per dose:

At least 25 females were mated and dosed in each group (25-27: pregnant and surviving to termination 20-22/group).

Control animals:

yes, sham-exposed

other: positive controls, given aspirin at 150 mg/kg

Examinations

Maternal examinations:

On gestation Day 17 dams terminated and subjected to caesarean section. Urogenital tracts examined for abnormality.

Ovaries and uterine content:

Implantation and resorption sites counted, plus live and dead foetuses.

Fetal examinations:

Live foetuses weighed. All foetuses sexed and examined for external abnormality, then examined in detail:
- one third of each litter examined for visceral/soft tissue abnormalities (x10 magnification used to aid inspection)
- remainder processed for skeletal examination (KOH then alizarin red stain).

Statistics:

Results tabulated/dam:
- implant sites
- resorption sites
- Live and dead foetuses
- male/female embryos
- average foetus weight/litter.

Indices calculated per group:
- live litters
- implant sites: total and average/dam
- resorptions: total number, dams with 1 or more, dams with complete resorption, % with 1 or more, % with complete resorption
- live foetuses: total and average/dam, sex ratio
- dead foetuses: total number, dams with 1 or more, dams with all dead, % with 1 or more, % with all dead
- average foetus weight.

Skeletal abnormality/variant indices:
-

Indices:

Results tabulated/dam:
- implant sites
- resorption sites
- Live and dead foetusess
- male/female embryos
- average foetus weight/litter.

Indices calculated per group:
- live litters
- implant sites: total and average/dam
- resorptions: total number, dams with 1 or more, dams with complete resorption, % with 1 or more, % with complete resorption
- live foetuses: total and average/dam, sex ratio
- dead foetuses: total number, dams with 1 or more, dams with all dead, % with 1 or more, % with all dead
- average foetus weight.

Skeletal abnormality/variant categories (reported/group as affected foetus number and number of litters with one or more affected)
- sternebrae (incompete ossification, bipartite, extra or missing)
- ribs (fused/split, wavy, >13)
- vertebrae (incomplete ossification)
- skull (incomplete closure)
- extremities (incomplete ossification, missing)
- hyoid (missing, reduced).

Soft tissue abnormalities: none observed, so not categorised.

Results and discussion

Results: maternal animals

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:

not specified

Dead fetuses:

no effects observed

Changes in pregnancy duration:

not specified

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not specified

Changes in number of pregnant:

no effects observed

Other effects:

no effects observed

Details on maternal toxic effects:

Maternal toxic effects:no effects. Remark: No adverse reactions to treatment are reported. Bodyweight data show no effect of treatment.

Details on maternal toxic effects:
Bodyweight increase over the test period was closely similar in test groups and the sham treatment controls (51-62% increase over 17 days)

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

>= 300 mg/kg bw/day (actual dose received)

Based on:

test mat.

Basis for effect level:

clinical signs

gross pathology

mortality

Results (fetuses)

Fetal body weight changes:

no effects observed

Description (incidence and severity):

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:

not specified

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

no effects observed

External malformations:

no effects observed

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

No pattern of increased skeletal abnormality or variation was seen in test groups when compared to concurrent controls. A 28% incidence of >+13 ribs in live foetuses of the 30 mg/kg/day test group compared to 12% in controls was not considered biologically significant in the absence of a similar increase at higher test dosages.

Visceral malformations:

not specified

Other effects:

no effects observed

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
No pattern of increased skeletal abnormality or variation was seen in test groups when compared to concurrent controls. A 28% incidence of >+13 ribs in live foetuses of the 30 mg/kg/day test group compared to 12% in controls was not considered biologically significant in the absence of a similar increase at higher test dosage.

Effect levels (fetuses)

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day

Based on:

test mat.

Sex:

not specified

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

no effects observed

Description (incidence and severity):

No pattern of increased skeletal abnormality or variation was seen in test groups when compared to concurrent controls. A 28% incidence of >+13 ribs in live foetuses of the 30 mg/kg/day test group compared to 12% in controls was not considered biologically significant in the absence of a similar increase at higher test dosage.

Overall developmental toxicity

Developmental effects observed:

no

Any other information on results incl. tables

Maternal data

Group	Live litters	Mean implants/dam	Dams with ≥1 resorption site	Total resorptions	Mean live foetuses/dam	Dams with ≥1 dead foetus (% of dams)	Mean foetal weight (g)
Sham treated control	20	12.7	7	13	12.0	1 (5%)	0.89
Test: 30 mg/kg/day	20	11.6	12	23	10.3	3 (14.3%)	0.89
Test: 95 mg/kg/day	20	12.8	9	16	11.9	2 (10.0%)	0.87
Test: 300 mg/kg/day	20	12.1	6	25	10.8	3 (13.6%)	0.93
Aspirin positive control	21	12.0	15	29	10.4	6 (27.3%)	0.84

Soft tissue abnormalities: none observed.

Skeletal findings

Group	Live foetuses examined	Sternebrae	Ribs	Vertebrae	Skull	Extremities	Hyoid*
Sham treated control	167 (20)	55 N (19) 8 B (7) 18 M (4)	20 + (9)	7 N (3)	3 N (2)	8 N (2) 1 M (1)	23 R (10)
Test: 30 mg/kg/day	149 (20)	49 N (17) 5 B (4) 18 M (6)	42 + (12)	7 N (4)		8 N (4)	19 R (11)
Test: 95 mg/kg/day	165 (20)	75 N (19) 5 B (5) 31 M (10)	23 + (12)	6 N (2)	1 N (1)	4 N (2)	33 R (14)
Test: 300 mg/kg/day	165 (20)	65N (16) 7 B (5) 1 + (1) 14 M (6)	27 + (13)	5 N (3)		8 N (4)	17 R (11)
Aspirin positive control	158 (21)	97 N (19) 7 B (4) 33 M (11)	9 F (2) 1 W (1) 45 + (13)	16 N (6)	3 N (2)	16 N (8)	29 R (13)

(n) = number of litters concerned

N = incomplete ossification(skull: incomplete closure)   B = bipartite  M = missing   F = fused/split

+ = extra (sternebrae) or >13 (ribs)   W = wavy   R = reduced

* Hyoid also shown as “missing” in 22 control foetuses and up to 32, 52 and 37 test group foetuses (30, 95, 300 mg/kg/day respectively): subsequently stated to indicate lost samples, not available for inspection due to errors at necropsy

Applicant's summary and conclusion

Conclusions:

Oral administration of test substance at up to 300 mg/kg/day produced no evidence of teratogenic effect and no clear evidence of embryotoxicity.