Hexadecyldimethylamine

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

weight of evidence

Study period:

06 SEP 1994 to 24 NOV 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: According to the OECD and it is GLP

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes (incl. QA statement)

Remarks:

according to Anhang 2 deutsches Chemikaliengesetz (1990)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Amines, C12-14-alkyldimethyl

EC Number:

283-464-9

EC Name:

Amines, C12-14-alkyldimethyl

Cas Number:

84649-84-3

Molecular formula:

R-N(Me)2, whereas R= C12-14-alkyl (even numbered, unbranched, saturated)

IUPAC Name:

N,N-dimethyl-C12-14-(even numbered)-alkyl-1-amines

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland GmbH
- Age at study initiation: 69-72 days
- Weight at study initiation: males: 313-340g and female: 216-242g
- Housing: individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 5 days

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: sesame oil, DAB 10

Details on exposure:

Administration volume: 2 mL/kg b.w. /day

PREPARATION OF DOSING SOLUTIONS:
- Rate of preparation of dosing solution (frequency): daily immediately before gavage treatment

VEHICLE
- Justification for use and choice of vehicle (if other than water): none given
- Amount of vehicle (if gavage): 2 ml/kg bw/day
- Lot/batch no. (if required): 12815; H. Lamotte, Bremen, Germany

Details on mating procedure:

Mating was monogamous: 1 male and 1 female animal were placed together in one cage during the dark period.
Each morning the female were examined for the presence of sperm. If findings were negative, mating was repeated.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

concentration and stability: immediately after the mixture as well as 8 and 24 h after storage
homogeneity: at the strat of administration, during administration as well as before administration to the last animal of each dose group.
concentration: during treatment with the test item always before administration to the last animal/dose-level group.

Duration of treatment / exposure:

Males: 14 days prior to mating and during the 14-day mating period
Female: 14 days prior to mating and during the mating period, pregnancy and lactation period.

Frequency of treatment:

administered orally at a constant volume of 2 mL/kg b.w/day on 7 days per week during the following periods:
males: two weeks prior to mating period and approx. 2 weeks post mating at least until the minimum total dosing period of 28 days had been completed.
females: throughout the study beginning two weeks prior to mating and continuing up to, and including, day 3 post partum or the day before sacrifice.

Details on study schedule:

1 adaptation week and approx. 54 test days [14 days premating, (up to) 14 days mating, 22 days gestation. 4 days lactation]

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 50, 150, 300 and 450 mg/kg b.w./day
Basis:
actual ingested

No. of animals per sex per dose:

control, low dose, low intermediate dose, high intermediate dose and high dose [ 10 males / 10 females] for all doses.

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: 14 day pilot study with 30, 100, 300 and 900 mg/kg bw/day reveled that 30 an 100 mg/kg bw/day were tolerated well, 900 mg/kg bw was lethal.

Positive control:

none

Examinations

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: first day of dosing , weekly thereadter and at termination

FOOD CONSUMPTION:
- Food consumption for each animal determined : Yes weekly

WATER CONSUMPTIO: No data

Oestrous cyclicity (parental animals):

number of corpora lutea and implants determined.

Sperm parameters (parental animals):

no data

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals after a minimum period of 28 days if no longer needed for further mating
- Maternal animals: All surviving animals were sacrificed on day 4 postpartum or shortly thereafter. females showing no evidence of copulation were sacrificed 24-26 days after the last day of the mating period.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera.

HISTOPATHOLOGY / ORGAN WEIGHTS
detailed histological examination of ovaries, testicles and epidiymides.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring were sacrificed at day 4 of age.
- These animals were subjected to postmortem macroscopic examinations

Statistics:

For all numerical values homogeneity of variance was tested using the bartlett chi-square test. When the varinances were homogenous, the Dunnett test (P<=0.01) was used t ocompare the experimental groups with the control group. In case heterogeneity of variances, Student´s t-test (p<=0.01) was carried out.. For the comparison of classificaton measurements, the chi2-test with Yates correction for continuity (n>=100) or FISHER´s exact test (n<100); p<=0.05 were used.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

no effects at 50 mg/kg bw day in male and female rats. At higher concentrations toxic effects and deaths observed. For details see below.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

lowest concentration: no effect, with increasing concentrations of test item body weight was reduced.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

lowest concentration: no effect, with increasing concentrations of test item body weight was reduced.

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

no effect in ovaries, testicles and epididymis.

Other effects:

not specified

Description (incidence and severity):

Test substance intake: gavage

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

not examined

Reproductive performance:

no effects observed

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
At 50 mg/kg bw/day, no deaths ocurred. At 150 mg/kg bw/day two female animals died, at 300 mg/kg bw/day one male and 6 female animals died between day 5 of exposure and day 3 of lactation. At 450 mg/kg bw/day one male and 2 females died during the night of the test day. The remaining animals showed a poor general condition. This test group was discontinued on test day 5.

male:
50, 150 mg/kg bw/day: no effects
300 mg/kg bw/day: reddened snouts, salivation, white point-shaped incrustation at the snout .
450 mg/kg bw/day: death of 1 animal, continous pilo-erection and sedation for up to 60 min. after each dosing. At day 5 animals humanely killed.

female.
50 mg/kg bw/day: no effects
150 mg/kg bw/day: pilo-erection, diarrhoea, reddened snouts, haemorrhagic canthi, soft faeces, moist anal-enital region, reduced motility.
300 mg/kg bw/day: pilo-erection, haemorrhagic snouts, salivation, reduced motility.
450 mg/kg bw/day: death of 2 animals, continous pilo-erection and sedation for up to 60 min. after each dosing. At day 5 animals humanely killed.

GROSS PATHOLOGY (PARENTAL ANIMALS)
male:
50 mg/kbg bw/day: no effects
150 and 300 mg/kg bw/day: changes in the stomach in form of a thickened and/or hardened cardia, parts of the mucosa were detached. A few to several ulcers were observed in individual animals.

female:
50 mg/kbg bw/day: no effects
150 and 300 mg/kg bw/day: thickened and/or hardened cardia of the stomach, parts of the mucosa were detached. One ulcer was detected.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
50 mg/kg bw/day: no influence on reproduction parameters.
150 mg/kg bw/day: pre-coital time and mean duration of pregnancy were within normal range. However parturition of two dams influenced: they did not deliver at all, mean post-implantation loss was significantly increased. Brood care was influenced in some animals.
300 mg/kg bw : only one female pup alive was born.

Effect levels (P0)

Dose descriptor:

NOEL

Effect level:

50 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: 150 mg/kg bw/day were in the beginning lethal range for pregnant rats.

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

mortality observed, treatment-related

Description (incidence and severity):

150 mg/kg bw/day. number of pups alive on day of delivery significantly reduced, stillbirth increased.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

150 mg/kg bw/day: body weight of male pubs reduced.

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

Details on results (F1)

No effects were seen at 50 mg/kg bw/day.

VIABILITY (OFFSPRING):
At 150 mg/kg bw/day the number of pups alive on day of delivery was significantly reduced, the rate of stillbirth increased.

BODY WEIGHT (OFFSPRING)
At 150 mg/kg bw/day the birth weight of the male pups was significantly reduced, the weight of the female pups was within the normal range.

OTHER FINDINGS (OFFSPRING)
At 150 mg/kg bw/day the mean post-implantation loss was significantly increased.

After treatment with 300 mg/kg bw/day only one female pup was alive.

Effect levels (F1)

Dose descriptor:

NOEL

Generation:

F1

Effect level:

50 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: At 150 mg/kg bw/day the number of pups alive was significantly reduced.

Overall reproductive toxicity

Reproductive effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In this reproduction / devolopment toxicity screening test with rats the no-observed-effect level (NOEL) for both parent animals and their pups was 50 mg test item/ kg b.w./day, by gavage. 150 mg/kg b.w./day were in the beginning lethal range for pregnant rats and in the toxic range for embryos/fetuses/pups.
Only one dam of the group treated with 300 mg/kg b.w./day delivered one female pup alive.
At 150 mg/kg b.w./day the number of pups alive war reduced. It can be concluded that effects in pubs were a consequence of maternal toxicity and not directly related to the applied substance.

Executive summary:

In a reproduction/ development toxicity screening test according to OECD guideline 421 the test substance was administered orally via gavage to male and female Sprague -Dawley rats. 14 days prior to mating and for the female rats until day four after delivery animals were treated with 0, 50, 150 , 300 or 450 mg/kg bw/day. Under the test conditions the no-observed-effect level (NOEL) for both parent animals and their pups was 50 mg test item/ kg b.w./day, by gavage. 150 mg/kg b.w./day were in the beginning lethal range for pregnant rats and in the toxic range for embryos/fetuses/pups. Only one dam of the group treated with 300 mg/kg b.w./day delivered one female pup alive. Reproduction was not affected except at already lethal concentrations.