Amides, C16-18, N-[3-(dimethylamino)propyl]

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-09-20 to 2012-11-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

Version / remarks:

July 1995

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: United States EPA Health Effects Test Guidelines, OPPTS 870.3550, Reproduction/Developmental Toxicity Screening Test, July 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

7651-02-7 (Stearic acid 3-(dimethylaminopropyl)amide)

IUPAC Name:

7651-02-7 (Stearic acid 3-(dimethylaminopropyl)amide)

Details on test material:

- Name of test material: Stearic acid 3-(dimethylaminopropyl)amide
- Physical state: solid
- Analytical purity: not indicated, treated as 100%

Test animals

Species:

rat

Strain:

other: Crl:WI(Han)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: (P) 11 wks
- Fasting period before study: no
- Housing:
Pre-mating: in groups of 5 animals/sex/cage in Macrolon plastic cages (MIV type, height 18 cm).
Mating: Females were caged together with males on a one-to-one-basis in Macrolon plastic cages (MIII type, height 18 cm).
Post-mating: Males were housed in their home cage (Macrolon plastic cages, MIV type, height 18 cm) with a maximum of 5 animals/cage. Females were individually housed in Macrolon plastic cages (MIII type, height 18 cm).
Lactation: Pups were kept with the dam until termination in Macrolon plastic cages (MIII type, height 18 cm).

- Diet (e.g. ad libitum): pelleted rodent diet, ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: at least 5 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-24
- Humidity (%): 40-70
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

propylene glycol

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Formulations (w/w) were prepared daily within 5 hours prior to dosing and were homogenised to a visually acceptable level. Adjustment was made for specific gravity of the vehicle. No correction was made for the purity/composition of the test substance.

VEHICLE
- Justification for use and choice of vehicle (if other than water): based on trial formulations
- Amount of vehicle (if gavage): 5 mL/kg body weight

Details on mating procedure:

- M/F ratio per cage: 1:1, avoiding sibling mating
- Length of cohabitation: max 14 d; females who had not shown evidence of mating were separated from their males
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged individually
One female was mated with a proven male of the same dose group since the male that she was intended to be mated with was sacrificed before mating.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Samples were analysed for homogeneity (highest and lowest concentration) and accuracy of preparation (all concentrations). Stability in vehicle over 5 hours at room temperature under normal laboratory light conditions was also determined (highest and lowest concentration).
Analysis with LC-MS/MS (lower limit of quantitation = 0.996 mg/g; calibration curve ranged from 1.00 to 25.0 mg/L)
The concentrations analysed in the formulations were in agreement with the target concentrations (mean accuracies between 85% and 115%).

Duration of treatment / exposure:

Males: 28 days (2 weeks prior to mating, during mating, up to the day prior to scheduled necropsy)
Females: 41 - 54 days (2 weeks prior to mating, during mating, during post-coitum, during at least 4 days of lactation (up to the day prior to scheduled necropsy)); one female of the control group was not dosed during littering

Frequency of treatment:

daily

Details on study schedule:

- F1 parental animals not mated (screening study)
- Parturition: females were allowed to litter normally; day 1 of lactation was defined as the day when a litter was found completed (i.e. membranes and placentas cleaned up, nest build up and/or feeding of pups started). Females that were littering were left undisturbed.

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 20, 70, 200 mg/kg bw/d
Basis:
actual ingested

No. of animals per sex per dose:

10

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on 14 day dose-range finding study with dose levels of 50, 200 and 500 mg/kg bw/d; considering the significant toxicity at 500 mg/kg bw/d, it was considered that dose levels for a subsequent study of longer duration should not exceed 200 mg/kg bw/d
- Rationale for animal assignment (if not random): Prior to commencement of treatment, by computer-generated random algorithm according to body weight, with all animals within ± 20% of the sex mean

Positive control:

no

Examinations

Parental animals: Observations and examinations:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: At least once daily; mortality/viability: at least twice daily

BODY WEIGHT: Yes
- Time schedule for examinations:
Males and females were weighed on the first day of exposure and weekly thereafter.
Mated females were weighed on Days 0, 4, 7, 11, 14, 17 and 20 post-coitum and during lactation on Days 1 and 4. High dose group males were weighed daily from 02-05 October 2012 (Days 11-14 of the premating period) in order to correct the actual dose volume for lower body weights recorded for these animals on a daily basis. Body weights determined daily between the regular body weight determinations (i.e. on Days 1, 8, 15, 22 and 28) are not reported since these were intended for calculation of the actual dose volumes only.

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Weekly, except for males and females which were housed together for mating and for females without evidence of mating. Food consumption of mated females was measured on Days 0, 4, 7, 11, 14, 17 and 20 post-coitum and on Days 1 and 4 of lactation.


WATER CONSUMPTION AND COMPOUND INTAKE: Yes
- Subjective appraisal was maintained during the study, but no quantitative investigation was introduced as no treatment related effect was suspected

OTHER:
General reproduction data
Male number paired with, mating date, confirmation of pregnancy, and delivery day were recorded. Pregnant females were examined to detect signs of difficult or prolonged parturition, and cage debris of pregnant females was examined to detect signs of abortion or premature birth. Any deficiencies in maternal care (such as inadequate construction or cleaning of the nest, pups left scattered and cold, physical abuse of pups or apparently inadequate lactation or feeding) were examined.

Oestrous cyclicity (parental animals):

no

Sperm parameters (parental animals):

Parameters examined in P male parental generations:
testis weight, epididymis weight, other: staging of spermatogenesis, histopathology of testes and epididymides in control + high dose group, histopathology of reproductive organs (coagulation gland, epididymides, prostate gland, seminal vesicles, testes) of males suspected to be infertile

Litter observations:

STANDARDISATION OF LITTERS
no

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring:
number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain
Mortality / Viability: numbers of live and dead pups on Day 1 of lactation and daily thereafter were determined. If possible, defects or cause of death were evaluated.
Clinical signs: At least once daily, detailed clinical observations were made for all animals.
Body weights: Live pups were weighed on Days 1 and 4 of lactation.
Sex: Sex was determined for all pups on Days 1 and 4 of lactation.

GROSS EXAMINATION OF DEAD PUPS:
yes, for external abnormalities; possible cause of death was determined for pups born or found dead

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals, Following completion of the mating period (a minimum of 28 days of dose administration).
- Maternal animals: All surviving animals, females which delivered: lactation days 5-7; female no. 74 which failed to deliver (no evidence of mating): 21 days after the last day of the mating period
Euthanized in extremis : When pain, distress or discomfort was considered not transient in nature or was likely to become more severe

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

HISTOPATHOLOGY / ORGAN WEIGHTS
The tissues indicated in Table 1 were prepared for microscopic examination and weighed, respectively.

Postmortem examinations (offspring):

SACRIFICE
- Pups surviving to planned termination were killed by decapitation on Days 5-7 of lactation.
- These animals were subjected to postmortem examinations (macroscopic examination) as follows:

GROSS NECROPSY
- Gross necropsy consisted of external examinations

HISTOPATHOLOGY / ORGAN WEIGTHS
Not performed

Statistics:

The following statistical methods were used to analyze the data:
-If the variables could be assumed to follow a normal distribution, the Dunnett-test (Ref. 2; many-to-one t-test) based on a pooled variance estimate was applied for the comparison of the treated groups and the control groups for each sex.
-The Steel-test (Ref. 3; many-to-one rank test) was applied if the data could not be assumed to follow a normal distribution.
-The Fisher Exact-test (Ref. 4) was applied to frequency data.

All tests were two-sided and in all cases p < 0.05 was accepted as the lowest level of significance.

Group means were calculated for continuous data and medians were calculated for discrete data (scores) in the summary tables. Test statistics were calculated on the basis of exact values for means and pooled variances. Individual values, means and standard deviations may have been rounded off before printing. Therefore, two groups may display the same printed means for a given parameter, yet display different test statistics values.

Reproductive indices:

Mating index (Number of females mated/Number of females paired x 100),
Fertility index (Number of pregnant females/Number of females paired x 100),
Conception index (Number of pregnant females/Number of females mated x 100),
Gestation index (Number of females bearing live pups/Number of pregnant females x 100)

Offspring viability indices:

Percentage live males at First Litter Check (Number of live male pups at First Litter Check/Number of live pups at First Litter Check x 100),
Percentage of postnatal loss Days 0-4 of lactation (Number of dead pups on Day 4 of lactation/Number of live pups at First Litter Check x 100),
Viability index (Number of live pups on Day 4 post partum/Number of pups born alive x100)

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

obserevd effects were due to gavage trauma, not substance-related

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

not examined

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

effects observed, treatment-related

Details on results (P0)

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
- No test substance-related mortality occurred during the study period.
Two males at 200 mg/kg bw/d (nos. 31 and 37) and one female at 70 mg/kg bw/d(no. 66) were euthanized in extremis on Days 11 (nos. 37 and 66) or Day 20 (no. 31): macroscopic and microscopic examinations suggested that gavage trauma was the cause of morbidity for these animals; the deaths were not substance-related

- no toxicologically relevant clinical signs were noted
- 200 mg/kg bw/d: hunched posture was noted among all males primarily during the second week of treatment, and at lower incidence, rales, piloerection and lean appearance were noted among some males. These findings had resolved for most animals as treatment progressed.
- clinical signs noted for the animals euthanized in extremis (nos. 31, 37 and 66) included (but were not limited to) hunched posture, rales, gasping, abdominal swelling, piloerection, lethargy and laboured respiration and chromodacryorrhoea, and were considered to be due to gavage trauma.
- salivation noted at 70 and 200 mg/kg bw/d was considered to be a physiological response rather than a sign of systemic toxicity considering the nature and minor severity of the effect and its time of occurrence (i.e. after dosing). This sign may be related to the taste of the test substance. No toxicological relevance was ascribed to these changes.

Incidental findings: included rales, alopecia and scabs; the incidence remained within the range of background findings to be expected for rats of this age and strain housed and treated under the conditions in this study; these were not considered to be toxicologically relevant


BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
200 mg/kg bw/d
- males showed weight loss up to 15% of day 1 weight during the first 2 weeks of treatment, which largely recovered during the treatment period
- mean body weight and body weight gain remained statistically significantly lower throughout treatment, but body weight gain exceeded that of controls during the mating period
- females showed minor (statistically significant) reduced body weight gain during the first two weeks of treatment
- at start of post-coitum, mean body weight was similar to control levels, but body weight (gain) was lower during the post coitum phase
- absolute and relative food consumption was reduced for males during the premating period, and for females during the first week of the premating period
- for males, food consumption had recovered to control levels during the mating period, while for females food consumption remained slightly lower throughout the post-coitum and lactation period

70 mg/kg bw/d
- slightly lower (but statistically significant) body weight gain was noted for females during the last week of the post coitum phase
- lower absolute and relative food consumption for females at 70 mg/kg bw/d throughout the post-coitum and lactation period (statistically significant on most occasions)


REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS)
- spermatogenic staging profiles were normal for males examined
- testes and epididymides weights were unaffected by treatment


REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
- significantly lower number of implantation sites at 200 mg/kg bw/d
- attributable to low numbers for female nos. 79 and 80; upon exclusion of the values for these two females, the mean was similar to that of the 70 mg/kg bw/d group

- mating, fertility and conception indices, precoital time, and number of corpora lutea were unaffected by treatment
- in one female the number of pups born was slightly higher than the number of implantations and corpora lutea recorded; this was considered to be caused by normal resorption of these areas as these enumerations were performed on Day 7 of lactation

- No toxicologically relevant effects on the gestation index and duration, parturition, maternal care and early postnatal pup development (mortality, clinical signs, body weight and macroscopy)

- significantly lower mean number of living pups at first litter check at 70 and 200 mg/kg bw/d
- at 200 mg/kg bw/d, 4/9 females had litter sizes of 3-9 pups (the lowest litter size was found for the two females with a low number of implantation sites)
- at 70 mg/kg bw/d, 5/9 females had litter sizes of 7-9 pups
- in the control group, 1/10 female had a litter size of 8 pups, while all other females had litter sizes of 12-15
- the historical control mean values for litter size in this lab is 11.8 (st.dev.= 2.47), n=588 litters (min=2, max=18), 95% confidence interval: 7-15.


ORGAN WEIGHTS (PARENTAL ANIMALS)
- Testes and epididymides weights were unaffected by treatment.
- lower terminal body weights for males at 200 mg/kg bw/d were in line with the lower in-life body weight noted for these animals


GROSS PATHOLOGY (PARENTAL ANIMALS)
Macroscopic observations at necropsy did not reveal any alterations that were attributable to treatment with the test substance.

Perforation of the esophagus was noted for two animals (male no. 37 (200 mg/kg bw/d) and female no. 66 (20 mg/kg bw/d)) that were euthanised in extremis. This was considered direct evidence that these deaths were considered due to gavage trauma. For the other male at 200 mg/kg bw/d euthanised in extremis (no. 31) macroscopic findings were not directly indicative of gavage trauma, but based on histopathological assessment this death was also ascribed to a gavage-related incident. Other macroscopic findings noted for these deaths included emaciated appearance, gastro-intestinal tract distended with gas, red foci on the lungs, irregular surface of the forestomach, reddish discoloration of the mesenteric lymph node or the stomach glandular mucosa, reduced size of the spleen and/or thymus.

The incidence of other necropsy findings noted for control and/or treated animals remained within the background range of findings encountered among rats of this age and strain, and did not show a dose-related trend. They were not considered to be toxicologically relevant.


HISTOPATHOLOGY (PARENTAL ANIMALS)
- no test item related microscopic findings
- no findings in the reproductive organs for animals that failed to sire or deliver healthy offspring that were outside the range of normal background pathology
- spermatogenic staging profiles were normal for males examined

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

parental

Effect level:

70 mg/kg bw (total dose)

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: body weight; food consumption

2

Dose descriptor:

NOAEL

Remarks:

fertility

Effect level:

70 mg/kg bw/day

Based on:

act. ingr.

Sex:

female

Basis for effect level:

other: lower number of implantation sites

3

Dose descriptor:

NOAEL

Remarks:

fertility

Effect level:

200 mg/kg bw (total dose)

Based on:

act. ingr.

Sex:

male

Basis for effect level:

other: overall effects

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

no effects observed

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)

VIABILITY (OFFSPRING)
One pup in the control, 70 and 200 mg/kg bw/d groups went missing during lactation. These pups were most likely cannibalised. No toxicological relevance was attributed to these dead/missing pups since the mortality incidence did not show a dose-related trend and remained within the range considered normal for pups of this age. No pups died or went missing at 20 mg/kg bw/d.

CLINICAL SIGNS (OFFSPRING)
Scabs on the left foreleg were noted for two pups at 200 mg/kg bw/d. The nature and incidence of this finding remained within the range considered normal for pups of this age, and was therefore not considered to be toxicologically relevant.

BODY WEIGHT (OFFSPRING)
Body weights of pups were unaffected by treatment up to 200 mg/kg bw/d.

GROSS PATHOLOGY (OFFSPRING)
Scabs on the left foreleg were noted for two pups at 200 mg/kg bw/d were incidental in nature. The nature and incidence of this finding remained within the range considered normal for pups of this age, and was therefore not considered to be toxicologically relevant.

Effect levels (F1)

Dose descriptor:

NOAEL

Remarks:

development

Generation:

F1

Effect level:

200 mg/kg bw/day

Based on:

act. ingr.

Sex:

not specified

Basis for effect level:

other: overall effects

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Reproduction data

The number of implantation sites was statistically significantly lower at 200 mg/kg bw/d. This was attributable to low numbers for female nos. 79 and 80. Upon exclusion of the values for these two females, the mean was similar to that of the 70 mg/kg group bw/d.

The mating, fertility and conception indices, precoital time, and number of corpora lutea were unaffected by treatment.

For female no 42, the number of pups born was slightly higher than the number of implantations and corpora lutea recorded. This was considered to be caused by normal resorption of these areas as these enumerations were performed on Day 7 of lactation.

 

Developmental data

No toxicologically relevant effects on the gestation index and duration, parturition, maternal care and early postnatal pup development (mortality, clinical signs, body weight and macroscopy) were observed.

The gestation index and duration of gestation were unaffected by treatment up to 200 mg/kg bw/d.

No signs of difficult or prolonged parturition were noted among the pregnant females.

Examination of cage debris of pregnant females revealed no signs of abortion or premature birth and no deficiencies in maternal care were observed.

The number of dead pups at first litter check, postnatal loss, viability index and sex ratio were unaffected by treatment, and clinical signs, body weight and external macroscopy did not reveal treatment-related findings.

The mean number of living pups at first litter check was significantly lower than controls at both 70 and 200 mg/kg bw/d. At 200 mg/kg bw/d, four of the nine females had litter sizes of 3-9 pups (the lowest litter size was found for the two females with a low number of implantation sites) and five of nine females at 70 mg/kg bw/d also had litter sizes of 7-9 pups. In contrast, only one female in the control group had a litter size of 8 pups, while all other females had litter sizes of 12-15. The historical control mean values for litter size in this lab is 11.8 (st.dev.= 2.47), n=588 litters (min=2, max=18), 95% confidence interval: 7-15.

 

Mortality

One pup in the control, 70 and 200 mg/kg bw/d groups went missing during lactation. These pups were most likely cannibalized. No toxicological relevance was attributed to these dead/missing pups since the mortality incidence did not show a dose-related trend and remained within the range considered normal for pups of this age. No pups died or went missing at 20 mg/kg bw/d.

Clinical signs

Scabs on the left foreleg were noted for two pups at 200 mg/kg bw/d.The nature and incidence of this finding remained within the range considered normal for pups of this age, and was therefore not considered to be toxicologically relevant.

 

Body weights

Body weights of pups were unaffected by treatment up to 200 mg/kg bw/d.

 

Macroscopy

Scabs on the left foreleg were noted for two pups at 200 mg/kg bw/d were incidental in nature.The nature and incidence of this finding remained within the range considered normal for pups of this age, and was therefore not considered to be toxicologically relevant.

 

 

Body weights of parental animals

At 200 mg/kg bw/d, most males showed weight loss (up to 15% of Day 1 values) during the first two weeks of treatment. Body weights largely recovered as treatment progressed. Although mean body weight and body weight gain remained statistically significantly lower throughout treatment, body weight gain exceeded that of controls during the mating period (by comparison of mean body weight increase over Days 1-15 of the mating period).

For females at 200 mg/kg bw/d, statistically significant reduced body weight gain was noted during the first two weeks of treatment. At start of post-coitum, mean body weight was similar to control levels, but body weight (gain) was lower during the post coitum phase.

 

At 70 mg/kg bw/d, a slightly lower (but statistically significant) body weight gain was noted for females during the last week of the post coitum phase.

   

Applicant's summary and conclusion

Conclusions:

Based on the results of this Reproduction/Developmental Toxicity Screening Test, the following NOAELs were derived for Stearic acid 3-(dimethylaminopropyl)amide:
parental NOAEL: 70 mg/kg bw/d
fertility NOAEL, females: 70 mg/kg bw/d
fertility NOAEL, males: 200 mg/kg bw/d
developmental NOAEL: 200 mg/kg bw/d

Executive summary:

In a Reproduction/Developmental Toxicity Screening Test according to OECD guideline 421 (July 1995) Stearic acid 3-(dimethylaminopropyl)amide (100% a.i.) was administered to groups of 10 Wistar rats/sex/dose inby gavageat dose levels of 0, 20, 70 and 200 mg/kg bw/d. 

Males were exposed for 28 days, i.e. 2 weeks prior to mating, during mating, and up to termination. Females were exposed for 41 – 54 days, i.e. during 2 weeks prior to mating, during mating, duringpost-coitum, and during at least 4 days of lactation.

 

At 200 mg/kg bw/d, males showed weight loss up to 15% of day 1 weight during the first 2 weeks of treatment, which largely recovered during the treatment period. The mean body weight and body weight gain remained statistically significantly lower throughout treatment. Females of the same dose group showed statistically significant reduced body weight gain during the first two weeks of treatment, as well as during pregnancy. Food intake was reduced for males during the premating period, and for females during the first week of the premating period; for females food intake remained slightly lower throughout pregnancy and lactation.

No treatment-related changes were noted in any of the remaining parental parameters investigated in this study (i.e. macroscopic examination, organ weights, and microscopic examination).

 

The mean number of corpora lutea was slightly lower in the 70 and 200 mg/kg bw/d dose groups compared with the control animals, however, this was not statistically significant.

A statistically significant lower number of implantation sites were noted for females at 200 mg/kg bw/d. This wasattributable to extremely low numbers of implantation sites in two females (3 and 6, respectively); upon exclusion of the values for these two females, the mean number of implantation sites was similar to that of the 70 mg/kg bw/d group, which showed also a slight, but not statistically significant reduction of implantations when compared to control animals.

A statistically significant lower number of living pups was noted in the 70 and 200 mg/kg bw/d dose groups. However, as the lower litter size correlated with lower number of implantation sites also when regarding single animals, this was considered to be a consequence of the reduced number of implantation sites.

No treatment-related changes were noted in any of the remaining reproductive parameters investigated in this study (i.e. mating, fertility and conception indices and precoital time, testes and epididymides weights, spermatogenic staging profiles).

 

Due to the remarkable effects on body weight /body weight gain and food consumption, the observed fertility effects – reduced number of implantation sites and subsequently lower litter size – are considered to be a consequence of general parental toxicity.

 

Based on these results, the following NOAELs were derived:

parental NOAEL: 70 mg/kg bw/d

fertility NOAEL, females: 70 mg/kg bw/d

fertility NOAEL, males: 200 mg/kg bw/d

developmental NOAEL: 200 mg/kg bw/d