(hexadecylamidopropyl)trimethylammonium chloride

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

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:

guideline study

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: 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:

N-[3-(dimethylamino)propyl]stearamide

EC Number:

231-609-1

EC Name:

N-[3-(dimethylamino)propyl]stearamide

Cas Number:

7651-02-7

Molecular formula:

C23H48N2O

IUPAC Name:

N-[3-(dimethylamino)propyl]octadecanamide

Test material form:

solid: pellets

Test animals

Species:

rat

Strain:

other: Crl:WI(Han)

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

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%).

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 individuallyOne 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.

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

Duration of test:

Males: 28 days
Females: 41 - 54 days

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

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

Doses / concentrations 2

Dose / conc.:

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

Doses / concentrations 3

Dose / conc.:

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

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

Examinations

Maternal 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.

Ovaries and uterine content:

n/a

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.

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)
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: maternal animals

General toxicity (maternal animals)

Clinical signs:

no effects observed

Description (incidence and severity):

- 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

Mortality:

mortality observed, non-treatment-related

Description (incidence):

- 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

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

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

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

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

200 mg/kg bw/d
- 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
- 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)

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

- Testes and epididymides weights were unaffected by treatment.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

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.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

- 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

Histopathological findings: neoplastic:

not examined

Maternal developmental toxicity

Number of abortions:

no effects observed

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

no effects observed

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed

Changes in number of pregnant:

no effects observed

Details on maternal toxic effects:

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.

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Remarks:

maternal toxicity

Effect level:

70 mg/kg bw (total dose)

Based on:

act. ingr.

Basis for effect level:

body weight and weight gain

food consumption and compound intake

Results (fetuses)

Fetal body weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

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.
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed
Field "Description (incidence and severity)" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.DescriptionIncidenceAndSeverityFetalPupBodyWeightChanges): Body weights of pups were unaffected by treatment up to 200 mg/kg bw/d.

Reduction in number of live offspring:

effects observed, non-treatment-related

Description (incidence and severity):

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.

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Changes in postnatal survival:

no effects observed

External malformations:

no effects observed

Skeletal malformations:

not examined

Visceral malformations:

not examined

Details on embryotoxic / teratogenic effects:

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.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: overall effects

Fetal abnormalities

Abnormalities:

no effects observed

Overall developmental toxicity

Developmental effects observed:

no

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 fertility NOAEL, females: 70 mg/kg fertility NOAEL, males: 200 mg/kg developmental NOAEL: 200 mg/kg

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

fertility NOAEL, females: 70 mg/kg

fertility NOAEL, males: 200 mg/kg

developmental NOAEL: 200 mg/kg