Hexylamine

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

19 Jan 1994 - 14 Feb 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study Please refer to section 13 (read across statement).

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

2002

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Butylammonium chloride

EC Number:

223-369-1

EC Name:

Butylammonium chloride

Cas Number:

3858-78-4

IUPAC Name:

butan-1-aminium chloride

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: DR. K. THOMAE GmbH, Biberach an der Riss, Germany
- Age at study initiation: 75 - 82 days
- Weight at study initiation: 237 g (mean)
- Housing: singly in type DK III stainless steel wire mesh cages
- Diet: Kliba 343 feed rat/mouse/hamster (KLINGENTALMUHLE AG, Kaiseraugst, Switzerland) ad libitum
- Water: water ad libitum
- Acclimation period: 5 days.


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 24 °C
- Humidity (%): 30 - 70 %
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

VEHICLE
- double distilled water
- Justification for use and choice of vehicle (if other than water): TS is water soluble
- Concentration in vehicle: 64.9 %
- Amount of vehicle (if gavage): 34.5 %

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Stability and purity verified by potentiometric titration

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1/1-3
- Length of cohabitation: 15.5 h
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

6-15 d p.c.

Frequency of treatment:

1x/d

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 400, and 1000 mg/(kg*d) (in 10 ml dissolved in water)
Basis:
nominal in water
These salt doses are equivalent to approx. 66, 265, and 660 mg amine base/(kg*d) (66 % of the HCl salt).

No. of animals per sex per dose:

22-24 pregnant females per group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
The TS concentration was based on observations made from a range finding study with pregnant rats

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: 1x/d

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: 1x/d


BODY WEIGHT: Yes
- Time schedule for examinations: on days 0, 1, 3, 6, 8, 10, 13, 15, 17 and 20 p.c.
Corrected body weight gain was calculated after the terminal sacrifice (terminal body weight on d 20 p.c. minus weight of unopened uterus minus body weight on d 6 p.c.).

FOOD CONSUMPTION AND COMPOUND INTAKE: Yes / on days 0, 1, 3, 6, 8, 10, 13, 15, 17 and 20 p.c.
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data



POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: uterus, ovary, placenta

The weight of the unopened uterus, the number of corpora lutea, the number and distribution of implantations, as well as live fetuses and dead implantations were determined.

The weight and sex ratio of fetuses was also determined. Further determinations were made of fetuses by macroscopic examinations, soft tissue examinations were made after fixation in BOUIN's solution (approx. half of the fetuses) and skeletal examinations were made on half of the fetuses after fixation in alcohol and staining according to the method of DAWSON (Stain Technol. 1, 123, 1926).

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No data

Statistics:

The Dunnett-test was used for a simultaneous comparison of several dose groups with the control.
Fisher's Exact test was used for pairwise comparisons.
The WILCOXON test was used for a comparison of each dose with the control for the hypothesis of equal medians.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
At 1000 mg/kg bw:
- A statistically significant reduction in food consumption during days 6-13 p.c. (ca. 8% lower than the corresponding control).
- A statistically significant impairment of body weight gain (14% less than controls if calculated for the total treatment period).
- A statistically significant lower mean gravid uterus weight (ca. 13% lower than the control group).
- A statistically significant increased number of resorptions, increased post-implantation loss value,
and lower mean percentage of live fetuses
- A statistically significant decrease in the mean placental weight (20%).

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

400 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
At 400 mg/kg bw
- A statistically significant increase in the rate of fetuses with soft tissue malformations was seen. Namely, 3 fetuses from 3 different
litters showed the same or similar malformations of the heart, great vessel or the diaphragm as seen at the 1000 mg/kg bw .

At 1000 mg/kg bw::
- Lower mean percentage of live fetuses
- Decrease in fetal body weight (8%)
- Slight, but statistically significant increase in the rate of external, soft tissue and total malformations was observed.
This included the occurrence of two rare external malformations of the tail (filiformed or kinky tail) in 3 fetuses from 3 different litters
and several malformations of the heart, the great vessels and the diaphragm in 6 fetuses out of 4 litters.
- A statistically significant increased rate of fetuses with skeletal retardations (esp. incomplete ossification of the skull and sternebra(e)) was noted.
This last finding should be seen in relation to the lower mean fetal body weights.

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

LOAEL

Effect level:

400 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Summary of maternal and fetal data after oral exposure to n-butylamine hydrochloride (from Gamer et al. 2002, Tab. 1)

Dose [mg/kg*day]	0	100	400	1000
Females mated	25	25	25	25
Number of maternal deaths, abortions, premature births and total resorptions	0	0	0	0
Females pregnant at scheduled necropsy	22	24	22	24
Mean gravid uterus weight (g)	77.5 ±15.9	78.1 ±11.3	76.5 ±15.7	67.1 ±11.6*
Mean net maternal body weight gain from day 6 post coitum (g)	44.0 ±6.6	42.8 ±9.9	50.4 ±8.8	45.8 ±9.5
Mean corpora lutea	16.3 ±2.2	16.9 ±1.9	16.0 ±2.4	15.9 ±2.1
Mean implantation sites	14.3 ±2.6	15.4 ±2.2	15.0 ±2.2	14.3 ±2.6
Mean % pre-implantation loss	12.1	8.8	6.3	9.8
Mean % post-implantation loss	5.7	9.5	11.0	12.5*
Mean % early resorptions	4.3	6.4	8.2	10.0
Mean % late resorptions	1.4	3.1	2.8	2.5
Mean number of live fetuses per litter	13.5 ±2.8	13.9 ±2.2	13.4 ±2.9	12.5 ±2.5
Number of dead fetuses	0	0	0	0
Mean placenta weight (g)	0.44 ±0.04	0.43 ±0.04	0.41 ±0.03	0.35 ±0.04**
Mean fetal weight (g)	3.8 ±0.3	3.8 ±0.2	3.8 ±0.2	3.5 ±0.3**
Percentage of litters with any malformation	18	21	36	46*
Mean % of fetuses/litter with any malformation	2.5	1.6	3.8	6.2*

group means +- S.D. 

* P 0.05; ** P 0.01

Fetal and litter incidence of external, soft tissue and skeletal malformations after oral administration of n-butylamine hydrochloride (from Gamer et al. 2002, Tab. 2)

Dose [mg/kg*day]	0	100	400	1000
Number of litters with live fetuses	22	24	22	24
Total number of fetuses examined (soft tissue/skeletal examination)	296 (144/152)	333 (161/172)	295 (143/152)	300 (143/157)
Number (%) of litters with external malformation	0 (0 %)	0 (0 %)	0 (0 %)	3 (13 %)
Number of fetuses (mean % fetuses/litter) with external malformation	0 (0 %)	0 (0 %)	0 (0 %)	3 (1 %)
Number (%) of litters with soft tissue malformation	0 (0 %)	0 (0 %)	3 (14 %)	4 (17 %)
Number of fetuses (mean % fetuses/litter) with soft tissue malformation	0 (0 %)	0 (0 %)	3 (3 %*)	6 (4 %*)
Number (%) of litters with skeletal malformation	4 (18 %)	5 (21 %)	6 (27 %)	7 (29 %)
Number of fetuses (mean % fetuses/litter) with skeletal malformation	7 (5 %)	5 (3 %)	7 (5 %)	10 (6 %)
Number (%) of litters with any malformation	4 (18 %)	5 (21 %)	8 (36 %)	11 (46 %*)
Number of fetuses (mean % fetuses/litter) with any malformation	7 (4 %)	5 (2 %)	10 (4 %)	19 (6 %*)

group means +- S.D.

*) P 0.05