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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
other: experimental study with 1,6 hexanediol, a chemical analogue of 1,5-pentanediol
Adequacy of study:
weight of evidence
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
yes (incl. QA statement)
Limit test:
yes

Test material

Constituent 1
Chemical structure
Reference substance name:
Hexane-1,6-diol
EC Number:
211-074-0
EC Name:
Hexane-1,6-diol
Cas Number:
629-11-8
Molecular formula:
C6H14O2
IUPAC Name:
hexane-1,6-diol
Details on test material:
- Name of test material (as cited in study report): 1,6-Hexanediol
- Physical state: solid, colourless
- Analytical purity: 95.9%
- Lot/batch No.: 000STD77L0
- Expiration date of the lot/batch: 22.01.2014
- Stability under test conditions: The stability of the test substance in drinking for 7 days at room temperature was demonstrated before the start of the administration period
- Storage condition of test material: ambient (room temperature)

Test animals

Species:
rat
Strain:
Wistar
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services GmbH, Sulzfeld, Germany
- Age at study initiation: 10-12 weeks
- Housing: During the study period, the rats were housed individually in Makrolon type M III cages supplied by Becker & Co
- Diet: ground Kliba maintenance diet mouse/rat “GLP”, meal ad libitum
- Water: ad libitum
- Body weight: body weight of the pregnant animals on day 0 varied between 145.6 – 186.8 g.
- Acclimatization: yes
- Reason for choice of species: The Crl:WI(Han) strain was selected since extensive historical control data is available from the test facility for Wistar rats. This specific strain has been proven to be sensitive to substances with a teratogenic potential.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24°C
- Humidity (%): 30-70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:

The aqueous test substance preparations were prepared at the beginning of the administration period and thereafter at maximum intervals of 7 days, which took into account the period of established stability.
For the test substance preparations, the test substance was heated up to 42 degrees Celsius, the specific amount of test substance was weighed, topped up with drinking water in a calibrated beaker and intensely mixed with a magnetic stirrer (40 degrees Celsius), until it was completely dissolved.

Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The analyses of the test substance preparations were carried out at the Analytical Chemistry Laboratory of Experimental Toxicology and Ecology of BASF SE, Ludwigshafen, Germany. Analytical verifications of the stability of the test substance in drinking water over a period of a maximum of 7 days at room temperature were carried out prior to the start of the study
Details on mating procedure:
- Impregnation procedure: purchased timed pregnant
- Proof of pregnancy: vaginal plug/sperm referred to as day 0 of pregnancy
Duration of treatment / exposure:
GD6-19
Frequency of treatment:
Daily in the morning
Duration of test:
On GD 20, the females were sacrificed in a randomized order and examined macroscopically. The fetuses were removed from the uterus and investigated
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 100, 400, 1000 mg/kg/d
Basis:
actual ingested
No. of animals per sex per dose:
25 females
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: Since no adverse effects have been observed in previous study, dams were dosed with the limit doese, i.e. 1000 mg/kg/d

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: : twice on workdays, daily on weekends/public holidays

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: All animals were weighed on GD 0, 1, 3, 6, 8, 10, 13, 15, 17, 19 and 20. The body weight change of the animals was calculated based on the obtained results.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption: The consumption of food was recorded for the intervals GD 0-1, 1-3, 3-6, 6-8, 8-10, 10-13, 13-15, 15-17, 17-19 and 19-20.

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day #20

Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes / No / No data
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
Statistics:
DUNNETT-test (twosided), FISHER'S EXACT test (onesided), WILCOXON-test (onesided)
Indices:
The conception rate (in %) was calculated according to the following formula:
(number of pregnant animals/number of fertilized animals) x 100

The preimplantation loss (in %) for each individual pregnant animal which underwent scheduled sacrifice was calculated according to the following formula:
((number of corpora lutea – number of implantations)/number of corpora lutea)) x 100

The postimplantation loss (in %) for each individual pregnant animal which underwent scheduled sacrifice was calculated according to the following formula:
((number of implantations – number of live fetuses)/number of implantations) x 100
Historical control data:
Was used to assess whether observed differences were within historical control range

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:no effects

Details on maternal toxic effects:
One female from test group 0 (control) and 3 (1000 mg/kg/d) were not pregnant and therefore excluded from the analyses.
Mortality:
There were no test substance-related or spontaneous mortalities in any female of all test groups (0, 100, 400 or 1000 mg/kg bw/d).
Cliical signs:
No clinical signs or changes of general behavior, which may be attributed to the test substance, were detected in any female at dose levels of 100, 400 or 1000 mg/kg bw/d during the entire study period.
Food Consumption:
The mean food consumption of the dams in all dose groups (100, 400 or 1000 mg/kg bw/d) was generally comparable to the concurrent control throughout the entire study period.
Body weight:
The mean body weights of the dams in test groups 1-3 (100, 400 or 1000 mg/kg bw/d) were in general comparable to the controls throughout the entire study period; if changes occured they were considered incidential and without toxicological significance. If calculated for the entire treatment period (GD 6-19), the body weight change of the dams in test group 3 was statistically significantly reduced (approx. 9% below control). As there was neither an effect evident on the corrected body weight gain nor on carcass or uterine weights this minor change may well be a spurious finding.
Corrected (net) body weight gain:
The corrected body weight gain of test groups 1-3 (100, 400 and 1000 mg/kg bw/d) revealed no difference of any biological relevance to the corresponding control group. Moreover, mean carcass weights remained also unaffected by the treatment
Uterus weight:
The mean gravid uterus weights of the animals of test group 1-3 (100, 400 and 1000 mg/kg bw/d) were not influenced by the test substance. The differences between these groups and the control group revealed no dose-dependency and were assessed to be without biological relevance.
Necropsy findings:
No test substance-related or spontaneous findings occurred at necropsy in any dam.
Reproduction data:
The conception rate varied between 96% (control and test group 3) and 100% (test groups 1 and 2). With these rates, a sufficient number of pregnant females were available for the purpose of the study. There were no test substance-related and/or biologically relevant differences between test groups 0, 1, 2 and 3 (0, 100, 400 and 1000 mg/kg bw/d) in conception rate, in the mean number of corpora lutea and implantation sites or in the values calculated for the pre- and the postimplantation losses, the number of resorptions and viable fetuses. All observed differences are considered to reflect the normal range of fluctuations for animals of this strain and age.

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: developmental toxicity

Results (fetuses)

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

Details on embryotoxic / teratogenic effects:
Sex distribution of the fetuses:
The sex distribution of the fetuses in test groups 1-3 (100, 400 and 1000 mg/kg bw/d) was comparable to the control fetuses. Any observable differences were without biological relevance.
Weight of the placentae:
The mean placental weights of the low-, mid- and high-dose groups (100, 400 and 1000 mg/kg bw/d) were comparable to the corresponding control group.
Weight of the fetuses:
The mean fetal weights of test groups 1, 2 and 3 (100, 400 and 1000 mg/kg bw/d) did not show any biologically relevant differences in comparison to the control group. However, the mean fetal weight of female fetuses was slightly, but statistically significantly decreased in the high-dose group. As this marginally changed value lay well within the historical control range, it is considered to reflect the normal range of fluctuations for animals of this strain and age.
Fetal external malformations:
External malformations were recorded for two fetuses of the control and test group 3 (0 and 1000 mg/kg bw/d) each, and one fetus of test group 1 (100 mg/kg bw/d). Female low-dose fetus No. 43-03 and male high-dose fetus No. 77-04 had more than one malformation affecting the head. The total incidence of external malformations in treated animals did not differ significantly from the control group and was comparable to the historical control data.
Fetal external variations:
No external variations were recorded.
Fetal external unclassified observations:
No external unclassified observations were recorded.
Fetal soft tissue malformations:
Soft tissue malformations were recorded for two fetuses of test group 3 (1000 mg/kg bw/d). The total incidence of soft tissue malformations in treated animals did not differ significantly from the control group and was comparable to the historical control data.
Fetal soft tissue variations:
Some soft tissue variations were detected in all test groups including the control (0, 100, 400 or 1000 mg/kg bw/d), i.e. short innominate, dilated renal pelvis and dilated ureter. These variations were neither statistically significantly different from control nor dose-dependent and therefore, not considered biologically relevant.
Fetal soft tissue unclassified observations:
No unclassified soft tissue observations were recorded.
Fetal skeletal malformations:
Some skeletal malformations were detected in single fetuses of test groups 1-3 (100, 400 and 1000 mg/kg bw/d) affecting the skull, vertebral column, sternum, ribs, fore- and hindlimbs and the pelvic girdle. The incidences of these malformations were neither statistically significantly different from control nor dose-dependent and therefore, not considered biologically relevant. Most of them or congeneric findings can be found in the historical control data
Fetal skeletal variations:
For all test groups, skeletal variations of different bone structures were observed, with or without effects on corresponding cartilages. The observed skeletal variations were related to several parts of fetal skeleton and appeared without a relation to dosing. The overall incidences of skeletal variations were comparable to the historical control data. The increased incidences of skeletal variations were neither related to dose nor were they outside the historical control range.
Fetal skeletal unclassified cartilage observations:
Some isolated cartilage findings without impact on the respective bony structures, which were designated as unclassified cartilage observations, occurred in all test groups. The observed unclassified cartilage findings were related to the skull, the vertebral column, the sternum and ribs and did not show any relation to dosing.
Assessment of all fetal external, soft tissue and skeletal observations:
There were noted external, soft tissue and skeletal malformations in all test groups. The distribution of total malformations about the groups was not related to dose. No unclassified external or soft tissue observations were recorded for any of the fetuses in this study.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day
Basis for effect level:
other: developmental toxicity/teratogenicity

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
No need for classification.