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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Study does not state a specific OECD guideline and is not GLP compliant, but it does seem to follow OECD guideline 414 closely with a well documented methodology and results.

Data source

Referenceopen allclose all

Reference Type:
study report
Title:
Unnamed
Year:
1981
Report Date:
1981
Reference Type:
secondary source
Title:
Unnamed
Year:
1981

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): M-phenylenediamine (PD.)
- Physical state: A pale gray, finely-crystalline, odorless and water-soluble substance.
- Analytical purity: 99%.
- Stability under test conditions: Stability was checked.
- Storage condition of test material: Protected from light and kept under nitrogen in a refrigerator.
- Other: Received from Fluka AG, Buchs, Switzerland.

Test animals

Species:
rat
Strain:
other: Him: OFA (SD) SPF
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Forschungs-insitut fur Verscuchstierzucht (Research Institute for Test Animal Breeding), Himberg
- Age at study initiation: 6-10 months old
- Weight at study initiation: 200-250 g
- Housing: Kept individually in Type III Makrolon cages
- Diet (e.g. ad libitum): Ad litbitum with Altromin Breeding Diet 1314 ff, 10-mm pellets sterilized by gamma radiation, 2 Mrad
- Water- Autoclaved tap water ad libitum from drinking bottles

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21± 2°C
- Humidity (%): 55± 5%
- Air changes (per hr): 15 times per hour with pure fresh air
- Photoperiod (hrs dark / hrs light): Exclusively artificial light (200 lux at a height of 2m) for 10 hours ( from 7 AM - 5 PM) without dawn.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
The test substance was dissolved or suspended fresh daily and administered perorally once daily in the morning from the 6th to the 15th test days inclusive, using a metal esophageal probe.
Analytical verification of doses or concentrations:
not specified
Details on analytical verification of doses or concentrations:
No data.
Details on mating procedure:
- Impregnation procedure: Co-housed
- If cohoused:
- M/F ratio per cage: No data
- Verification of same strain and source of both sexes: Yes
- Proof of pregnancy: Vaginal plug, referred to as gestational day (GD) 0 of pregnancy
Duration of treatment / exposure:
Daily from GD 6 to GD 15
Frequency of treatment:
Daily
No. of animals per sex per dose:
25 mated rats
Control animals:
yes, concurrent vehicle
other: Acetylsalicylic acid was given as a positive control
Details on study design:
- Dose selection rationale: Range-finding study
- Rationale for animal assignment (if not random): Based on a random number table

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes.
- Time schedule: Daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: 0, 6, 15, and 20th day

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: ovaries and uterus
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes.
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
- Approximately one third of the judgable fetuses were collectively fixed for later evaluation of internal organs. The other two thirds were eviscerated and the organs were evaluated for completeness and possible malformations.
- Spinal column: The number of cervical, thoracic, lumbar and caudal vertebrae and the number of ossification centers.
- Sacrum was evaluated.
- Pelvic bones and ribs were evaluated and counted.
- Bones of extremities.
- Sternal ossification centers were determined.
- All cranial bones were investigated for the presence and degree of ossification.
- Number of ribs and sternal ossification centers were recorded.
Statistics:
Either the mean x together with the standard deviation s and sample size n or the absolute or percentage frequency is given. Data, with means and standard deviations, were compared by simple variance analysis and then a Scheffe test. With events for which there are absolute numbers and percentages or these can be calculated, first of all a kth 2-field chi2 test was applied using the related numbers that were also used for the calculation of the percentages. If significant differences were indicated, further checking was done with the four-field chi2 test. With small population numbers, Fischer's Exact Test was used. A significant limit of p = 0.05 was established for all tests.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Six of the dams in the highest-dose group died before the 20th day.

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEL
Effect level:
90 mg/kg bw/day
Basis for effect level:
other: developmental toxicity
Dose descriptor:
NOAEL
Effect level:
30 mg/kg bw/day
Basis for effect level:
other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
Statistically significant differences as compared to the negative control were found only in the highest-dose group. These differences manifested themselves as a reduction in the number of litters with live pups, lower average placenta weights, fewer total number of live pups, fewer live pups per litter, lower average body weight of a live pup, as well as an increase in the total resporptions, greater total number of late-dying embryos, greater total number of early dying embryos, higher percentage of dams with fetuses having minor alterations and greater frequency of fetuses having minor malformations. Major malformations were not found.
The postive control group showed the expected malformations in proportionate frequency and confirmed the sensitivity of the testing system.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
30 mg/kg bw/day
Basis for effect level:
other: fetotoxicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
no

Applicant's summary and conclusion

Conclusions:
The test substance is strongly fetotoxic and might be weakly teratogenic, although only with doses high enough to be injurious to the dam.
Executive summary:

Rats were evaluated in a developmental toxicity study via oral doses of 10, 30, and 90 mg/kg bw/day. Maternal toxicity in the form of lethality occurred in the 90 mg/kg bw/day exposure group only. Reduction in the number of litters with live pups, lower average placenta weights, fewer total number of live pups, fewer live pups per litter, lower average body weight of a live pup, as well as an increase in the total resporptions, greater total number of late-dying embryos, greater total number of early dying embryos, higher percentage of dams with fetuses having minor alterations and greater frequency of fetuses having minor malformations occurred in the 90 mg/kg bw/dayexposure group. Thus, these effects occurred at maternally toxic concentrations. The test substance was not uniquely toxic to the developing fetus. The NOAEL for maternal systemic effects was 30 mg/kg bw/day. The NOAEL for fetal developmental effects was 30 mg/kg bw/day.