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

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Read-across from Klimisch 1 study performed on a close structural analogue which is manufactured in the same way (reaction of formaldehyde with a modified urea) and reacts with water in the same way (hydrolysis releasing formaldehyde) as the registered substance

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPP 82-1 (90-Day Oral Toxicity)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1-[1,3-bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]-1,3-bis(hydroxymethyl)urea

EC Number:

278-928-2

EC Name:

1-[1,3-bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]-1,3-bis(hydroxymethyl)urea

Cas Number:

78491-02-8

Molecular formula:

C8H14N4O7

IUPAC Name:

1-[1,3-bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]-1,3-bis(hydroxymethyl)urea

Test material form:

other: aqueous 50% solution

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

42 days old at start of treatment: bodyweights males 175-195g, females 145-178g. Individually housed; animal room 19-23C, 30-80% humidity, 12h dark/light cycle. Food and water provided ad lib.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

(distilled)

Details on oral exposure:

Gavage dosing at 5 ml/kg dose volume.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Stability (up to14 days) and homogeneity of formulated doses was confirmed. Achieved concentrations were confirmed by analysis of samples taken weekly to Week 4, then in Weeks 7, 10 and 13.
Analytical method: after addition of a colour reagent to diluted samples and heating (70C, 1h), absorbance at 492nm was determined.

Duration of treatment / exposure:

91 or 92 days (staggered termination).

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
200 mg/kg
Basis:
other: ingested dose (corrected for active ingredient)

Doses / concentrations 2

Remarks:

Doses / Concentrations:
500 mg/kg
Basis:
other: ingested dose (corrected for active ingredient)

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1000 mg/kg
Basis:
other: ingested dose (corrected for active ingredient)

No. of animals per sex per dose:

20 males, 20 females

Control animals:

yes, concurrent vehicle

Details on study design:

Samples from 10M, 10F/group taken for haematology, clinical chemistry and urinalysis.

Positive control:

No

Examinations

Observations and examinations performed and frequency:

Twice daily cageside observations. Detailed weekly observations including bodyweight.
Opthalmoscopy: pretest and at termination.
Blood samples taken at termination, after fasting: full haematology and clinical chemistry.
Urinalysis: at termination.

Sacrifice and pathology:

Macroscopic observations at necropsy.
Organ weights: adrenals, brain, heart, kidneys, liver, lungs, ovaries, pituitary, spleen, testes with epididymides, thyroid/parathyroids, uterus.

Tissues collected: weighed organs plus aorta (thoracic), bone and bone marrow (sternum/femur), oesophagus, eyes with optic nerve, intestine (caecum, colon, ileum, jejunum, rectum), lacrymal gland, lymph nodes, mammary gland, sciatic nerve, pancreas, prostate, salivary glands, seminal vesicles, skeletal muscle, skin spinal cord (cervical, thoracic, lumbar), stomach, thymic region, trachea, urinary bladder, uterus with cervix, gross lesions.

Histopathology: all collected tissues from control and high-dose groups plus decedents. Kidneys, liver, lungs, stomach, adrenals, gross lesions for other test groups.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

2 males died at 1000 mg/kg/day. Excessive salivation seen at 500 and 1000 mg/kg/day.

Mortality:

mortality observed, treatment-related

Description (incidence):

2 males died at 1000 mg/kg/day. Excessive salivation seen at 500 and 1000 mg/kg/day.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

decreased in males dosed at 1000 mg/kg/day.

Food consumption and compound intake (if feeding study):

no effects observed

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Haemoglobin, haematocrit and erythrocyte counts were significantly decreased, leucocyte counts increased at 1000 mg/kg/day (both sexes); erythrocytes were significantly decreased in males at 500 mg/kg/day.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

At 1000 mg/kg/day glucose, total protein, albumin and globulin significantly decreased, albumin/globulin ratio increased. Total protein, globulin and albumin/globulin ration were reduced at 500 mg/kg (and glucose decreased in males).

Urinalysis findings:

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Absolute and relative adrenal weights increased significantly at 1000 and at 500 (males only) mg/kg/day. In females absolute and relative liver weights increased significantly at 1000 and 500 mg/kg/day, pituitary weights decreased at 1000 mg/kg/day.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Stomach lesions (nodules, masses, swelling) seen at 1000 mg/kg/day.

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Necrotising gastritis of forestomach and/or glandular stomach seen at 500 and 1000 mg/kg/day (severe at 1000 mg/kg/day).

Details on results:

Homogeneity and stability of test doses plus achieved concentrations (within 20% of nominal values) were confirmed by analysis.

Effect levels

1

Dose descriptor:

NOEL

Effect level:

200 mg/kg bw/day (actual dose received)

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: Based on stomach lesions and associated clinical pathology parameters observed at 500 and 1000 mg/kg/day.

Remarks on result:

other: 1-[1,3-bis(hydroxymethyl)-2,5-dioxoimidazolidin-4-yl]-1,3-bis(hydroxymethyl)urea (CAS# 78491-02-8)

2

Key result

Dose descriptor:

NOEL

Effect level:

280 mg/kg bw/day (nominal)

Based on:

other: analogue: CAS# 78491-02-8

Sex:

male/female

Basis for effect level:

other: See above

Remarks on result:

other: Comparing the difference in molecular weight between the registered substance and its analogue, a factor of 1.4 should be applied on the NOEL.

Target system / organ toxicity

Critical effects observed:

yes

Lowest effective dose / conc.:

500 mg/kg bw/day (actual dose received)

System:

gastrointestinal tract

Organ:

stomach

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

Daily oral dosing of rats at 200 mg/kg/day produced no effects considered treatment-related: this is concluded to be the NOEL for the tested analogue. Main target organ was identified as the fore-and glandular stomach. Based on the similarity of chemical structure and properties including hydrolysis to release formaldehyde, it is predicted that the registered substance will show a similar toxicological profile.