Adiponitrile

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Oct 22, 1979 through November 15, 1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was not conducted according to guidelines but was conducted according to GLPs and the report contains sufficient data for interpretation of results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1980

Report date:

1980

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Objective of study was to establish dosage levels of the test article for a teratology study. Test article was administered orally by gavage as a single daily dose on days 6 through 19 of gestation. Dams were observed for mortality, changes in appearance, body weight, and uterine examinations were conducted immediatley following sacrifice on gestation day 20.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Adiponitrile

EC Number:

203-896-3

EC Name:

Adiponitrile

Cas Number:

111-69-3

Molecular formula:

C6H8N2

IUPAC Name:

hexanedinitrile

Details on test material:

The test article was received from the Monsanto Company, St. Louis, Missouri, October 11, 1979.
Description: gold liquid
EHL Number: T790008
Chemical Name: Adiponitrile
Lot or Batch Number: FIT-7865
Special Storage Conditions: None-Flammable
Expiration date: None

Test animals

Species:

rat

Strain:

other: COBS CD

Details on test animals or test system and environmental conditions:

As cited in study report: Thirty untreated, sexually mature, virgin female Charles River COBS CD rats (The Charles River Breeding Laboratories Inc., Portage, Michigan) were used to establish dosage levels of adiponitrile for a teratology study. These rats were approximately 15 weeks of age at the time of mating and had been acclimated in this laboratory for a minimum of 10 days prior to study initiation. Each rat was assigned a unique number and ear-tagged for identification when placed on study. All rats were individually housed, except during mating, in suspended wire-mash cages and maintained in a temperature-, humidity- and light-controlled environment. Purina Certified Rodent Chow #5002 and tap water were available ad libitum. Each diet lot used was recorded.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

As cited in study report: A stock solution of the test article was prepared daily by adding adiponitrile to the vehicle Mazola corn oil (1 gm/10 ml), in a volumetric flash. Appropriate concentrations of the test article were prepared daily by admixing calculated amounts of the stock solution with Mazola corn oil and shaken by hand to ensure dissolution. The test article was prepared at concentrations to permit administration at dosage levels of 10, 25, 50, 100 and 200 mg/kg/day at a constant volume of 10 ml/kg. A magnetic stir bar and plate were used during administration. The test article was administered orally by gavage as a single daily dose on days 6 through 19 of gestation. The control group received the vehicle only on a comparable regimen at a volume of 10 ml/kg. Individual dosages were determined from individual body weights recorded on gestation day 6.

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

As cited in study report: One female and one male rat of the same strain were placed together for mating. The occurrence of copulation was determined by daily inspection for a copulatory plug or by a vaginal inspection for sperm. The day evidence of mating was detected was designated day 0 of gestation and the female was returned to an individual cage.

Duration of treatment / exposure:

Single dose by gavage

Frequency of treatment:

Daily

Duration of test:

Days 6 through 19 of gestation

Doses / concentrations

Remarks:

Doses / Concentrations:
10, 25, 50, 100, and 200 mg/kg/day
Basis:
actual ingested

No. of animals per sex per dose:

5 females (P) per dose

Control animals:

yes, concurrent vehicle

Details on study design:

Mated females were consecutively assigned in a block design to one control and five treatment groups consisting of five rats each.

Examinations

Maternal examinations:

As cited in the study report: Prior to treatment, the dams were observed daily for mortality and overt changes in appearance and behavior. They were observed daily for mortality and clinical signs of toxicity on days 6 through 20 of gestation. Individual maternal body weights were recorded on gestation days 0, 6, 9, 12, 16 and 20.

Ovaries and uterine content:

As cited in study report: On gestation day 20, all surviving dams were sacrificed by carbon dioxide inhalation. Immediately following sacrifice, the uterus and ovaries were exposed by an abdominal incision. The number and location of viable and nonviable fetuses, early and late resorptions and the number of total implantations and corpora lutea were recorded. The abdominal and thoracic cavities and organs of the dams were examined for grossly evident morphological changes and the carcases discarded. Uteri from females that appeared nongravid were opened and placed in a 10% ammonium sulfide solution for confirmation of pregnancy status. A gross necropsy was performed on all rats not surviving to the scheduled sacrifice date in an attempt to determine a cause of death.

Fetal examinations:

Only viability of fetuses was examined.

Statistics:

no data

Indices:

The number and location of viable and nonviable fetuses, early and late resorptions and the number of total implantations and corpora lutea were recorded.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
There were no biologically meaningful differences in the appearance or behavior of rats in the 10, 25 or 50 mg/kg/day dosage groups when compared to the control group. Hair loss occurred infrequently in all treatment groups. Dried red or brown matter in the nasal region and yellow staining (and matting) of the anogenital region were noted prior to death in the majority of rats in the 100 and 200 mg/kg/day dosage groups. Increased activity was noted immediately after dosing in all surviving rats in these two treatment groups, on four consecutive days near the end of the treatment period. One rat in the 100 mg/kg/day dosage group died on gestation day 18 and all rats in the 200 mg/kg/day dosage group died between gestation days 8 and 18. Causes of death could not be determined at necropsy. The intestinal contents of all of these rats were liquid in form. Additional necropsy findings included congested lungs, stomach distended, hemorrhagic areas on the glandular mucosa and white raised areas on the nonglandular mucosa. When examined at the scheduled sacrifice, the intestinal contents of one female in the 100 mg/kg/day dosage group (Dam #38125) were described as being liquid in form (this female had resorptions only). There were no other remarkable necropsy findings at the scheduled uterine examination. There were no biologically meaningful differences in mean maternal body weight gain in the 10, 25 or 50 mg/kg/day dosage groups when compared to the control group. A moderate to severe decrease in mean body weight gain was noted in the 100 mg/kg/day dosage group over the treatment period.There were no biologically meaningful differences in the mean numbers of viable fetuses, postimplantation loss, early resorptions, total implantations or corpora lutea in the 10, 25 or 50 mg/kg/day dosage groups when compared to the control group. One dam in the 100 mg/kg/day dosage group had resorptions only (14 late, one early), which resulted in an increase in mean postimplantation loss in this dosage group.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

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

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

LOAEL

Effect level:

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

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:not examined

Details on embryotoxic / teratogenic effects:
Embryotoxicity/teratogenic effects not examined because this was a pilot study to determine dosage levels.

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

There were no biologically meaningful differences in mean maternal body weight gain or mean numbers of viable fetuses, postimplantation loss, early resorptions, total implantations or corpora lutea in the 10, 25 or 50 mg/kg/day dosage groups when compared to the control group, therefore the maternal toxicity NOAEL is 50 mg/kg/day. A moderate to severe decrease in mean body weight gain and mean implantation loss was noted in the 100 mg/kg/day dosage group over the treatment period. therefore the maternal toxicity LOAEL was 100 mg/kg/day.

Executive summary:

Pregnant Charles River COBS CD rats were used to establish dosage levels of adiponitrile for a teratology study. Dosage levels of 0, 10, 25, 50, 100 and 200 mg/kg/day were administered orally by gavage as a single daily dose on days 6 through 19 of gestation at a constant volume of 10 ml/kg. The control group received the vehicle only, Mazola corn oil, on a comparable regimen. Uterine examinations were performed on all surviving dams on gestation day 20. There were no biologically meaningful differences in appearance, behavior, mean maternal body weight gain or mean uterine examination observations in the 10, 25 or 50 mg/kg/day dosage groups when compared to the control group. One rat in the 100 mg/kg/day dosage group and all rats in the 200 mg/kg/day dosage group died. Causes of death could not be determined at necropsy. A moderate to severe decrease in mean maternal body weight gain over the treatment period and an increase in mean postimplantation loss (due to one dam with resorptions only) was noted in the 100 mg/kg/day dosage group.