Registration Dossier

Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1985
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well-documented publication that meets basic scientific principles.

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)
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/d of the test substance topically (2 h 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/d, 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 28 d old were fixed in buffered neutral formalin and those 28 d 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
Details on test material:
- 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
- Area of exposure: 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%
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:
Doses / Concentrations:
0, 10, 20 and 40 mg/kg bw/day
Basis:
other: Dermal application
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

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:no effects. Remark: No test substance related significant effects.

Details on maternal toxic effects:
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). 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. 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. No treatment-related maternal body weight or food intake effects were noted. A slight increase in congested lungs was observed for the high dose group at necropsy.

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEL
Effect level:
40 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOAEL
Effect level:
40 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Basis for effect level:
other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
The incidence of foetal malformation and genetic and developmental variation in the treated groups was comparable to that of the control group.

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Under the conditions of the study, the NOAEL of the test substance for maternal as well as developmental toxicity was found to be 40 mg/kg bw/d in rabbits.
Executive summary:

A guideline study was carried out to assess the effects of C16 TMAC on embryonic and foetal development 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 and genetic and developmental variations in the treated groups was comparable to that of the control group. No other treatment-related effects were noted. Under the conditions of the study, the NOAEL for maternal as well as developmental toxicity was 40 mg a.i./kg bw/day in rabbits.