N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 Oct 2005 - 07 Mar 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Version / remarks:

adopted January 22, 2001

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Freie und Hansestadt Hamburg, Behörde für Soziales, Familie, Gesundheit und Verbraucherschutz, Hamburg, Germany

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine

EC Number:

262-679-1

EC Name:

N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine

Cas Number:

61260-55-7

Molecular formula:

C24H50N4

IUPAC Name:

N1,N6-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexane-1,6-diamine

Test animals

Species:

rat

Strain:

other: CD/Crl: CD (SD)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland GmbH, Sulzfeld, Germany
- Age at study initiation: 8-9 weeks
- Weight at study initiation: 193-243 g
- Housing: singly in Makrolon cages
- Diet (ad libitum): commercial Ssniff R-Z V1324
- Water (ad libitum): tap water
- Acclimation period: 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 55 ± 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

The test substance is instable in water. Hence, corn oil was employed as vehicle. Test substance was suspended in the vehicle to the appropriate concentrations and was administered orally at a constant volume of 5 mL/kg bw. The dose of the test substance was adapted to the animal´s body weight daily.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

At start of the administration period and at termination (12 samples). The samples were analysed according to a gas chromatographic method.

Details on mating procedure:

Sexually mature male rats (8-9 weeks) served as partners. 1 male and 1 female animal were placed together in one cage during the dark period. Each morning a vaginal smear was taken to check for the presence of sperm and the stage of oestrus cycle. If findings were negative, mating was repeated with the same partner. The day on which sperm was found was considered as the day of conception (day 0 of pregnancy).

Duration of treatment / exposure:

GD 6-19

Frequency of treatment:

once daily

Duration of test:

until gestation day 20; 14 day treatment period

Doses / concentrations

Remarks:

Doses / Concentrations:
44, 110, 275 mg/kg bw/d
Basis:
nominal conc.

No. of animals per sex per dose:

25

Control animals:

yes, concurrent vehicle

Details on study design:

Dose levels were selected based on the results of the dose-range-finding study in rats (LPT study no. 19520/05, REG-No. 2005-0298-DGT). Test substance was administered to two dams/group once daily from the 6th to 19th day of pregnancy. Dose levels of 40, 120 and 360 mg/kg bw/d were administered at a constant administration volume of 5 mL/kg bw.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
behavior, external appearance and nature of faeces, viability

BODY WEIGHT: Yes
- Time schedule for examinations: body weight was recorded on day 0 of gestation followed by daily weighings. Body weight gain was also calculated in intervals.

FOOD CONSUMPTION: Yes
Quantity of food consumed by each rat was recorded daily with the exception of gestation day 20. Food intake per rat (g/rat/day) was calculated using the total amount of food given to and left by each rat in each group on completion of a treatment day. The relative food consumption was calculated.

WATER CONSUMPTION: Yes
- Time schedule for examinations: Daily monitoring by visual appraisal of the drinking water bottles was maintained throughout the study.

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day #20
- Organs examined: The ovaries and the uteri of the dams were removed; the uteri (in total) were weighed. In order to check for possible drug effects, a dissection with macroscopic examination of the internal organs and placentae of the dams was carried out on the day of scheduled laparatomy or on the day on which the animals were found dead. In case of macroscopical findings, the affected maternal tissues were preserved in 7% buffered formalin for possible future histopathological examinations.

Fetal examinations:

Fetuses were removed and following examinations performed: macroscopic inspection of the placentae (focal indurations), number of fetuses (alive and dead) and placentae, sex and viability, number and size of resorptions, corpora lutea in the ovaries, implantations and location of fetuses in the uterus, gravid uterus weight, weights of fetuses and weights of the placentae, fetuses were inspected externally for damages, especially for malformations

Statistics:

For all numerical values, homogeneity of variances was tested using the Bartlett chi-square test. When the variances were homogenous, the Dunnett test was used to compare the experimental groups with the control group. In case of heterogeneity of variances, the Student´s t-test was carried out.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
Mortality: 275 mg/kg bw/d: 3 of 21 pregnant dams died prematurely on GD 12 or 17
Clinical signs: 110 mg/kg bw/d: one dam showed piloerection on some test days; 275 mg/kg bw/d: pilo-erection, laboured breathing or clonic convulsions were noted in individual high-dosed dams on one to several test days
Body weight: 275 mg/kg bw/d: significant reductions were determined for the mean maternal body weight change on GD 6 to 9 and 9 to 12 and for the net weight change from day 6 onwards
Food and water consumption: no effects
Necropsy: 275 mg/kg bw/d: necropsy of the three prematurely decreased dams revealed reddened lungs in two dams and a reddened stomach in one dam.
Uterus and carcass weight: no effects

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
Corpora lutea, implantation sites, resorptions, weight and number of live fetuses, placental weights: no effects
Mortality: no
Malformations or Variations: no
Soft tissue evaluations: 275 mg/kg bw/d: slightly but significantly increased fetal and litter incidences for hemaorrhagic foci in the liver and for total soft tissue variations.
Retardations: no effects

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

275 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

NOAEL

Effect level:

110 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: embryotoxicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Analysis of the test substance-carrier mixtures revealed that formulations were correctly prepared and the results of 94.1% to 109.4% of the nominal value were within the admissible limits of 90% to 110%.

The maternotoxic effects reported in this study correlate with those observed in a subchronic study carried out with the test substance (refer to Section 7.5.1). In that study, all changes observed were considered to be due to the local corrosive changes noted, causing behavioural, biochemical and haematological changes and in some cases mortality. The changes observed were not considered to be due to systemic toxicity of the test substance given by gavage but due to its corrosive properties.

Applicant's summary and conclusion

Conclusions:

The test substance possessed no teratogenic properties up to a dose level of 275 mg/kg bw/d. No test substance-related increase was noted in the incidence of fetal malformations, external or skeletal variations. At the maternotoxic dose (275 mg/kg bw/d) marginal embryotoxic properties were noted in form of slightly increased incidences of soft tissue variations.