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Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Refer to the Quaternary ammonium salts (QAS) category or section 13 for details on the category justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Version / remarks:
see 'Principles of method if other than guideline'
Deviations:
yes
Remarks:
short exposure time i.e., on gestation Days 7-18 only
Principles of method if other than guideline:
- 20 mated female rabbits per group were exposed for Days 7 - 18 of gestation to 2.0 mL/kg bw/day of the test substance topically (2h per day) at concentrations of 0, 0.5, 1.0, or 2.0% (i.e., equivalent to 0, 10, 20 and 40 mg/kg bw/day, respectively). The control group was treated with deionised water.
- Animals were observed twice daily for signs of toxicity, including skin irritation from Days 7 to 29. Body weights and food consumption were recorded. A gross necropsy was conducted on animals that died. Foetuses less than 28d old were fixed in buffered neutral formalin and those 28d or older were cleared and stained. All surviving dams were sacrificed at study termination on gestation Day 29. An examination of the uterus and ovaries was conducted. Following removal of the foetuses the abdominal and thoracic cavities and organs of the dams were examined. At sacrifice foetuses were identified, weighed and examined externally for defects. Gross dissection and examination of viscera, and internal sex determination also were conducted on each foetus. Finally, an examination of the skeleton for anomalies and ossification variations was conducted after clearing and alizarin red staining of the foetuses.
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Specific details on test material used for the study:
- Name of test material (as cited in study report): 1-Hexadecanaminium, N,N,N-trimethyl-, chloride
- Physical state: Liquid
- Analytical purity: 25% aqueous solution

Test animals

Species:
rabbit
Strain:
New Zealand White

Administration / exposure

Route of administration:
dermal
Vehicle:
water
Details on exposure:
TEST SITE:
Shaved dorsal area.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Rinsed with water and dried.
- Time after start of exposure: 2 h.

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 2 mL/kg
- Concentration (if solution): 0, 0.5, 1.0 and 2.0%
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
Days 7 - 18 of gestation.
Frequency of treatment:
Once daily (2 hours).
Duration of test:
Days 0 - 29 of gestation.
Doses / concentrations
Remarks:
Concentrations: 0, 0.5, 1.0, or 2.0% (i.e., equivalent to 0, 10, 20 and 40 mg/kg bw/day, respectively)
No. of animals per sex per dose:
20 pregnant females per dose.
Control animals:
yes, concurrent vehicle

Examinations

Maternal examinations:
Dams were observed twice daily for signs of toxicity, including skin irritation from Days 7 through 29. Body weights were taken on gestation Days 0, 3, 6, 9, 12, 15, 18, 21, 24, 27 and 29. Individual food consumption was measured daily. A gross necropsy was conducted on dams that died in an attempt to determine the cause of death. All surviving dams were sacrificed at study termination on gestation Day 29. An examination of the uterus (including the number and location of live and dead foetuses, early and late resorptions, and implantation sites) and ovaries (including the number of corpora lutea) was conducted. Following removal of the foetuses the abdominal and thoracic cavities and organs of the dams were examined. Uteri from females that appeared non-gravid were placed in 10% ammonium sulphide solution for confirmation of pregnancy.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
- External examinations: Yes
- Soft tissue examinations: Yes
- Skeletal examinations: Yes
Statistics:
Body weight changes and food consumption and number of early and late resorptions, dead foetuses, total implantations, corpora lutea, skeletal abnormalities, and mean fetal body weight were compared by analysis of variance (Bartlette's). If variance was not significant, then treatment-control comparisons were made using the least significant difference (LSD) criterion. If variance was significant, then comparison was made using the t-test for unequal variances and the Wilcoxon, Mann-Whitney rank sum test. Additionally, a regression and lack of fit were performed on each of these parameters. The number of pregnancies per group, the percentage of skeletal abnormalities and soft tissue malformations were analysed by Fisher's exact test.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Dermal irritation (if dermal study):
effects observed, treatment-related
Description (incidence and severity):
Skin irritation was observed at all doses with the severity and duration of erythema, oedema, desquamation, atonia and coriaceousness increased in a dose-dependent manner.
Mortality:
mortality observed, non-treatment-related
Description (incidence):
Two control, one intermediate and one high dose doe died during the study. The cause of death could not be determined. Two of the does that died aborted prior to death (one control and one intermediate dose group animal).
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
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
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
A slight increase in congested lungs was observed for the high dose group at necropsy.
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined

Maternal developmental toxicity

Number of abortions:
effects observed, non-treatment-related
Description (incidence and severity):
Two additional abortions occurred, one each in the intermediate and high dose groups. None of these deaths or abortions were considered related to test substance toxicity.
Pre- and post-implantation loss:
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:
not examined
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not examined
Changes in number of pregnant:
not examined
Details on maternal toxic effects:
Maternal toxic effects: no test substance related significant effects.

Effect levels (maternal animals)

open allclose all
Key result
Dose descriptor:
NOAEL
Remarks:
systemic toxicity
Effect level:
40 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Basis for effect level:
other: no significant treatment-related maternal toxic effects were observed up to the highest tested dose.
Key result
Dose descriptor:
NOAEL
Remarks:
developmental toxicity
Effect level:
40 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Basis for effect level:
other: no significant treatment-related foetal development effects were observed up to the highest tested dose.

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

Fetal body weight changes:
not examined
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): not examined
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
not examined
Changes in litter size and weights:
no effects observed
Changes in postnatal survival:
not examined
External malformations:
no effects observed
Skeletal malformations:
no effects observed
Visceral malformations:
no effects observed
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects: no effects

Details on embryotoxic / teratogenic effects:
The incidence of foetal malformations, as well as genetic and developmental variations in the treated groups were comparable to that of the control group.

Effect levels (fetuses)

open allclose all
Key result
Dose descriptor:
NOAEL
Remarks:
general toxicity
Effect level:
40 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Sex:
male/female
Basis for effect level:
other: no effects observed up to the highest dose tested
Key result
Dose descriptor:
NOAEL
Remarks:
developmental toxicity
Effect level:
40 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Sex:
male/female
Basis for effect level:
other: no developmental effects observed up to the highest dose tested

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Applicant's summary and conclusion

Conclusions:
Based on the results of the read across study, the NOAEL of the test substance for maternal as well as developmental toxicity is considered to be 40 mg/kg bw/d in rabbits.
Executive summary:

A study was conducted to determine the developmental toxicity / teratogenicity of the read across substance, C16 TMAC, according to a method similar to OECD Guideline 414, in compliance with GLP. This experiment was performed in New Zealand White rabbits. Twenty mated female rabbits per group were exposed topically (daily for 2 hours) from Days 7 to 18 of gestation at concentrations of 0, 0.5, 1.0, or 2.0% (equivalent to 0, 10, 20 and 40 mg a.i./kg bw/day, respectively). The control group was treated with deionised water only. Clinical condition and reactions to treatment were recorded at least once daily. Body weights were recorded on Days 0, 3, 6, 9, 12, 15, 18, 21, 24, 27 and 29 of gestation. All surviving females were sacrificed on Day 29 of gestation and the foetuses were removed by caesarean section. At necropsy the females were examined macroscopically. Live foetuses were weighed, sexed and were examined for visceral and skeletal abnormalities. Two control animals, one intermediate and one high dose died during the study. Two of the rabbits that died, aborted prior to death (one control and one intermediate dose). Two additional abortions occurred, one each in the intermediate and high dose groups. Deaths or abortions were not considered to be related to the test substance. No treatment-related maternal body weight or food intake effects were noted. The incidence of foetal malformations, as well as genetic and developmental variations in the treated groups were comparable to that of the control group. No other treatment-related effects were noted. Based on the results of the read across study, the NOAEL of the test substance for maternal as well as developmental toxicity is considered to be 40 mg/kg bw/d in rabbits (Albridge, 1985).