Registration Dossier

Toxicological information

Developmental toxicity / teratogenicity

Currently viewing:

Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1981
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Detailed publication with some shortcomings in documentation (purity of test substance not stated, no statistical evaluation for the majority of end points)
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reference
Endpoint:
toxicity to reproduction
Remarks:
other: five generation study with embedded continuous breeding study
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1981
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: publication with some shortcomings in documentation (purity of test substance not stated, exposure duration not clearly stated, no statistical evaluation)
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Principles of method if other than guideline:
five generation study with embedded continuous breeding study
GLP compliance:
not specified
Limit test:
no
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 14-15 weeks
- Housing: individually
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2°C
- Photoperiod: 12 hrs dark/12 hrs light


Route of administration:
oral: feed
Details on exposure:
SEMIPURIFIED DIET
Casein: 20 %
Refined corn oil: 8%
Salt mix: 4%
Vitamin mix: 1%
Corn starch 33.5%
Dextrose: 33.5%

DIET PREPARATION
- test diets were prepared by substituting 1,3-butanediol for equal amounts by weight of corn starch and dextrose



Details on mating procedure:
- M/F ratio per cage: one male/ one female
- Length of cohabitation: 7 days
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
- After 7 days of unsuccessful pairing replacement of first male by another male.
- Further matings after two unsuccessful attempts: no
- After successful mating each pregnant female was caged individually.
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
F0 rats were treated 4 weeks before the mating period. Female rats of the F0 were fed diets containing 1,3-butanediol throughout the mating, gestation and lactating period. After 11 weeks of feeding, 25 males and 25 females from each dosage group of F1A animals were randomly selected and paired to produce the F2 generation (no further information).
Frequency of treatment:
daily
Details on study schedule:
At 1-2 weeks after weaning of the first litters (F1A), each female of the F0 generation was mated with a different male and a second series of litters was produced (F1B).
All animals of the F1B generation were discarded at weaning except for ten males per group, which were reared to sexual maturity and used in a dominant lethal test. Pubs of the F1A were reared to maturity. After 11 weeks of feeding, 25 males and 25 females from each dosage group of F1A animals were randomly selected and paired to produce the F2 generation. Five successive mating cycles were achieved with the F1A rats within a period of 77 weeks (F2A, F2B, F2C, F2D, F2E).
The F2B, F2C, F2D and F2E were examined and sacrificed as part of the continuous breeding phase of the study, while the F2A litter was mated to produce the F3A and F3B litters. The F3A litter was used for the cytogenetic portion of the study and was mated to produce the F4A and F4B litter, which are indicated by the chart in the orginal paper to be part of the cytogenicity study.
The pregnant dams of the F2A litters (producing the F3B) were divided in two groups: 1/4 were allowed to give birth normally and 3/4 were used for teratological examination on day 19 of gestation.
Remarks:
0, 5, 10 and 24 % nominal in diet, corresponding to 0, 2500, 5000 and 12000 mg/kg bw/day, calculated with food factor 0.05 according to Guidance on Information Requirements R.8
No. of animals per sex per dose:
25 rats per sex per dose group in the F0, F1A, F1B, F2A, F3A
Control animals:
yes, plain diet
Positive control:
none
Parental animals: Observations and examinations:
After 4 weeks of feeding of the F0 the respective diets, blood samples were collected from ten rats per sex per group for determination of alkaline phosphatase, glucose, hematocrit, hemoglobin and total and differential leucocyte counts. Urine analysis of the same animals provided measurements of albumin, glucose, ketones, occult blood, pH, specific gravity and microscopic examination. For F1A rats which survived at least 66 weeks, the gonads and pituitary glands were examined microscopically. During the eleventh week of feeding of F1A animals blood and urine samples were collected from ten rats per sex per group and evaluated as mentioned above.

Body weight: yes

Reproductive performance: yes
Litter observations:
viability, mean pub weight at day 4 and 21 post partum
Postmortem examinations (parental animals):
histopathologic examination of the testes or ovaries and pituitary glands of the F1A
Reproductive indices:
fertility (percent matings resulting in pregnancies) and gestation indices (percent pregnancies resulting in litters cast alive)
Offspring viability indices:
- percent pubs cast alive that survived to 4 days
- percent pups alive at 4 days that survived to 21 days
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
not specified
Histopathological findings: neoplastic:
not specified
Other effects:
not specified
Reproductive function: oestrous cycle:
not specified
Reproductive function: sperm measures:
not specified
Reproductive performance:
no effects observed

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Female animals showed no significant abnormal growth rates. Except the P0-Generation, body weight gains of male rats in all four consecutive generations were slightly depressed with an apparent dose relationship (for details see below). The efficiency of food utilization through 10 weeks of post-wening remained constant for all generations of both sexes and was not affected by 1,3-BD treatment.

CLINICAL STUDIES
Hematology, blood chemistry and urinalysis showed no trend associated with treatment for F0, F1, F2 and F3 generation animals

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
During five successive mating cycles of F1A rats, a gradual decrease in the pregnancy rate was seen. Both the number of pregnant females and the fertility index appeared to be dose-related for several series of F2 litters, especially F2D and F2E. For the fifth series of litters, no pups were obtained in the highest-dose group. However, the gestation, viability and lactation indexes, as well as the mean pup body weights at 4 and 21 days showed no significant differences between specific litter series or between control and test groups (excluding high-dose animals of the fifth series of litters). No significant treatment-related differences were noted on histopathologic examination of testes or ovaries and pituitary glands as a possible explanation of the observed reproductive failure during the fifth cycle.
For the other three generations of dams and pups, no significant dose-related trends were observed for the reproduction and lactation parameters, as described above.

Key result
Dose descriptor:
NOAEL
Effect level:
12 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: absence of adverse effects
Remarks on result:
other: dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Dose descriptor:
NOAEL
Effect level:
12 000 mg/kg bw/day
Based on:
test mat.
Sex:
female
Basis for effect level:
other: absence of effects on reproduction
Remarks on result:
other: dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Critical effects observed:
no
Lowest effective dose / conc.:
12 000 mg/kg bw/day (nominal)
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not specified
Other effects:
not specified
Reproductive function: oestrous cycle:
not specified
Reproductive function: sperm measures:
not specified
Reproductive performance:
effects observed, treatment-related
BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Female animals showed no significant abnormal growth rates. Body weight gains of adult male rats in four F1 generations were slightly depressed with an apparent dose relationship (for details see bel
ow). The efficiency of food utilization through 10 weeks of post-wening remained constant for all generations of both sexes and was not affected by treatment.
REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
During five successive mating cycles of F1A rats, a gradual decrease in the pregnancy rate was seen
. Both the number of pregnant females and the fertility index appeared to be dose-related for several
series of F2 litters, especially F2D and F2E. For the fifth series of litters, no pups were obtained in t
he highest-dose group. However, the gestation, viability and lactation indexes, as well as the mean
pup body weights at 4 and 21 days showed no significant differences between specific litter series or
between control and test groups (excluding high-dose animals of the fifth series of litters). No signifi
cant treatment-related differences were noted on histopathologic examination of testes or ovaries and
pituitary glands as a possible explanation of the observed reproductive failure during the fifth cycle.
For the other three generations of dams and pups, no significant dose-related trends were observed
for the reproduction and lactation parameters, as described above.
Key result
Dose descriptor:
LOAEL
Effect level:
12 000 mg/kg bw/day
Based on:
test mat.
Sex:
male
Basis for effect level:
body weight and weight gain
Remarks on result:
other: dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Dose descriptor:
LOAEL
Effect level:
12 000 mg/kg bw/day
Based on:
test mat.
Sex:
female
Basis for effect level:
reproductive performance
Remarks on result:
other: dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Dose descriptor:
NOAEL
Effect level:
5 000 mg/kg bw/day
Based on:
test mat.
Sex:
male
Basis for effect level:
body weight and weight gain
Remarks on result:
other: dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Dose descriptor:
NOAEL
Effect level:
5 000 mg/kg bw/day
Based on:
test mat.
Sex:
female
Basis for effect level:
reproductive performance
Remarks on result:
other: dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Critical effects observed:
yes
Lowest effective dose / conc.:
12 000 mg/kg bw/day (nominal)
System:
other: unspecific effects
Organ:
other: body weight gain
Treatment related:
yes
Dose response relationship:
yes
Relevant for humans:
yes
Key result
Critical effects observed:
yes
Lowest effective dose / conc.:
12 000 mg/kg bw/day (nominal)
System:
female reproductive system
Organ:
other: reduced fertility
Treatment related:
yes
Dose response relationship:
yes
Relevant for humans:
yes
Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Sexual maturation:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Histopathological findings:
not specified
Behaviour (functional findings):
not specified
Developmental immunotoxicity:
not specified
- no treatment related effects in F1 offspring (details for the effects of P1 generation (F2 litters) are presented above and in the attached document)
Key result
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
12 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no developmental toxicity
Remarks on result:
other: maternal dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Critical effects observed:
no
Lowest effective dose / conc.:
12 000 mg/kg bw/day (nominal)
System:
other: no developmental effects observed
Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Sexual maturation:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Histopathological findings:
not specified
Behaviour (functional findings):
not examined
Developmental immunotoxicity:
not examined
Key result
Dose descriptor:
NOAEL
Generation:
other: F2A-F2E
Effect level:
12 000 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no developmental effects
Remarks on result:
other: maternal dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Critical effects observed:
no
Lowest effective dose / conc.:
12 000 mg/kg bw/day (nominal)
System:
other: no developmental effects observed
Key result
Reproductive effects observed:
yes
Lowest effective dose / conc.:
12 000 mg/kg bw/day
Treatment related:
yes
Relation to other toxic effects:
reproductive effects in the absence of other toxic effects
Dose response relationship:
yes
Relevant for humans:
yes

Body weight gain of male rats is presented in the following table:

 Generation  Dietary level (%)  Weeks  Mean weight gain (g)
 F0  0  23  153
   5  23  149
   10  23  141
   24  23  149
 F1A  77  481
   5  77  429
   10  77  410
   24  77  383
 F1B  0  11  298
   5  11  278
   10  11  263
   24  11  257
 F2A  0  11  305
   5  11  282
   10  11  278
   24  11  272
 F3A  0  9  296
   5  9  270
   10  9  263
   24  9  222
Conclusions:
1,3-butylene glycol did not influence fertility in a five generation study with an embedded continuous breeding study in concentrations up to 10% in the diet (5000 mg/kg bw/d). In the highest concentration tested (24%, 12000 mg/kg bw/d) no offspring in the fifth litter of the F2 generation were produced.
Executive summary:

Twenty five animals of both sexes were fed either control diet or diet supplemented with 1,3-butylene glycol at dose levels of 5, 10 or 24% of the diet (2500, 5000 or 12000 mg/kg bw/d). Treatment with the test item had no influence on reproduction and lactation parameters for four of five generations of dams and pups. The pregnancy rate of F1A rats decreased during five successive mating cycles: no pups were obtained at the high-dose level group of the fifth series of litters (F2E generation). Excluding this group, the viability of F2 generation pups revealed no significant differences between litters or between control and test groups. Body weight gains of male rats in all four generations were slightly depressed with an apparent dose relationship. Body weight gain of females was not affected (Hess et al., 1981).

The study indicates that fertility is not impaired through 1,3 -butylene glycol exposure up to 10% in diet (5000 mg/kg bw/d).

Reason / purpose:
reference to same study
Reference
Endpoint:
in vivo mammalian germ cell study: cytogenicity / chromosome aberration
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1981
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well performed study (cytogenetic study over 3 generations!) with some shortcomings in study conception and documentation
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Principles of method if other than guideline:
genotoxicity test in vivo after subchronic oral exposure over 3 generations
GLP compliance:
not specified
Type of assay:
chromosome aberration assay
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 14-15 weeks
- Housing: individually
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2 °C
- Photoperiod: 12 h dark / 12 h light
Route of administration:
oral: feed
Details on exposure:
SEMIPURIFIED DIET
20% casein
8% refined corn oil
4% salt mix
1% vitamin mix
33.5% corn starch
33.5% dextrose

DIET PREPARATION
- test diets were prepared by substituting 1,3-butanediol for equal amounts by weight of corn starch and dextrose
Duration of treatment / exposure:
Rats were treated 4 weeks before the mating period. Female rats of the F0 were fed diets containing 1,3-butanediol throughout the mating, gestation and lactating period of the F1A generation. Pubs of the F1A were reared to maturity. After 11 weeks of feeding, 25 males and 25 females from each dosage group of F1A animals were randomly selected and paired to produce the F2A generation and the F2A litter was mated to produce the F3A generation.
Frequency of treatment:
daily
Post exposure period:
none
Remarks:
Doses / Concentrations:
5, 10, 24%
Basis:
nominal in diet
No. of animals per sex per dose:
At least two animals per sex and dose from the F1A, F2A and F3A generation were examined.
Control animals:
yes, plain diet
Positive control(s):
none
Tissues and cell types examined:
femur bone marrow
Details of tissue and slide preparation:
DETAILS OF SLIDE PREPARATION:
Animals were treated with 1 mg/kg bw colchicine intraperitoneally 3-4 h prior to examination (exact time point of examination not stated). The bone marrow was washed with 5 ml of hank's balanced salt solution (HBSS). The isolated cells were washed with HBSS repeatedly, suspended in hypotonic fetal calf serum and incubated for 20 min at 37 °C. Fixation of the cells was performed in methanol/glacial acetic acid (3:1 mixture) overnight at 4 °C and stained on coverslips with 2% aceto-orcein.

METHOD OF ANALYSIS:
100-250 metaphase cells per dose group were examined for chromosomal aberrations at 900x magnification by phase-contrast microscopy.


OTHER:
Statistics:
Statistical analysis was not stated.
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Remarks:
only slight depression of body weight gain
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
not examined
Additional information on results:
Dietary concentrations of 5, 10 and 24% correspond with body doses of 2000, 4000 and 9600 mg/kg bw for males and 2500, 5000 and 12000 mg/kg bw for females (based on a daily food consumption of 40 and 50 g/kg bw for males and females, respectively, according to the Guidance on Information Requirements R.8).

The number of abnormal cells was not increased with respect to the normal range of aberrant cells in untreated F1A, F2A and F3A animals. No specific abnormalities were observed in the treated animals and no dose-related effects were noted.

Conclusions:
The test substance did not induce chromosomal aberrations after subchronic oral exposure of rats over 3 generations with dietary concentrations of up to 24%.
Executive summary:

Rats were fed butane-1,3-diol in concentrations up to 24% of the diet and paired to produce F1A, F2A and F3A litters. Analysis of the femur bone marrow of at least two animals per sex and dose of these litters revealed no increase in chromosomal aberrations. This study was performed with doses high enough to cause a reduced body weight gain (Hess et al., 1981).

.

Reason / purpose:
reference to same study
Reference
Endpoint:
in vivo mammalian germ cell study: cytogenicity / chromosome aberration
Remarks:
Type of genotoxicity: other: chromosome aberration, gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1981
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well performed study with some shortcomings in documentation
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Reason / purpose:
reference to same study
Principles of method if other than guideline:
genotoxicity test in vivo after subchronic oral exposure
GLP compliance:
not specified
Type of assay:
rodent dominant lethal assay
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 14-15 weeks
- Housing: individually
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2 °C
- Photoperiod: 12 h dark / 12 h light
Route of administration:
oral: feed
Details on exposure:
SEMIPURIFIED DIET
20% casein
8% refined corn oil
4% salt mix
1% vitamin mix
33.5% corn starch
33.5% dextrose

DIET PREPARATION
- test diets were prepared by substituting 1,3-butanediol for equal amounts by weight of corn starch and dextrose
Duration of treatment / exposure:
Rats were treated 4 weeks before the mating period. Female rats of the F0 were fed diets containing 1,3-butanediol throughout the mating, gestation and lactating period of the F1A generation. At 1-2 weeks after weaning of the F1A litter, F0 females were mated with different males and the F1B generation was produced. Ten males per dose group were used for the dominant lethal test. They were housed individually in mating cages and fed the same diet concentrations as the F0 generation. For 8 consecutive weeks, 2 virgin females (100 days old) were introduced each week and remained for 7 days. Afterwards the females were kept individually for another 7 days and then examined.
Frequency of treatment:
daily
Post exposure period:
none
Remarks:
Doses / Concentrations:
5, 10, 24%
Basis:
nominal in diet
No. of animals per sex per dose:
ten males of the F1B generation
Control animals:
yes, plain diet
Positive control(s):
none
Tissues and cell types examined:
The reproductive tract of the mated females was examined with respect to the number of implantates, resorption sites, viable and dead fetuses
Evaluation criteria:
The mutagenic index (% resorptions/implantation sites) was calculated according to a method of Epstein and Schaffer (reference stated).
Statistics:
Statistical analysis was performed, but not stated in detail.
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Remarks:
only slight depression of body weight gain
Vehicle controls validity:
valid
Negative controls validity:
not examined
Positive controls validity:
not examined
Additional information on results:
Dietary concentrations of 5, 10 and 24% correspond with body doses of 2000, 4000 and 9600 mg/kg bw for males and 2500, 5000 and 12000 mg/kg bw for females (based on a daily food consumption of 40 and 50 g/kg bw for males and females, respectively, according to the Guidance on Information Requirements R.8).

The percentage of pregnancies as well as the percentage of viable fetuses per implantation site were not significantly different between treatment and control groups. The mutagenic index did not show a trend with increasing doses.

  control  5%  10%  24%
No. pregnancies total  106  97  130  117 
% Pregnancies (20 matings)  66.3  60.6  81.3  73.1 
Implant sites  1165  1024  1452  1310 
Viable fetuses total  1101  962  1389  1269 
% Viable fetuses/implant sites  94.5  94.0  95.7  96.9 
Resorptions total  64  62  63  41 
% Resorptions/implant sites*  5.5  6.1  4.3  3.1 

*:mutagenic index

Conclusions:
The test substance did not induce dominant lethal effects after subchronic oral exposure of rats with dietary concentrations of up to 24%.
Executive summary:

Rats were fed butane-1,3-diol in concentrations up to 24% of the diet and paired to produce F1A and F1B litters. Males of the F1B generation were used to examine dominant lethal effects after mating them with virgin females. The exposure did not cause a significant effect with respect to fertility, viable fetuses per implantation sites and percentage of resorption per implantation sites (mutagenic index). A dose-related trend was not evident. This study was performed at high doses, which produced reduced body weight gain (Hess et al., 1981).

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1981
Report Date:
1981

Materials and methods

Principles of method if other than guideline:
study on developmental toxicity
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Details on test material:
- Name of test material (as cited in study report): 1,3-butanediol
Test material obtained from Celanese Chemical Company, New York

Test animals

Species:
rat
Strain:
Wistar
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 14-15 weeks
- Housing: individually
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2°C
- Photoperiod: 12 hrs dark/12 hrs light




Administration / exposure

Route of administration:
oral: feed
Details on exposure:
SEMIPURIFIED DIET
Casein: 20 %
Refined corn oil: 8%
Salt mix: 4%
Vitamin mix: 1%
Corn starch 33.5%
Dextrose: 33.5%

DIET PREPARATION
- test diets were prepared by substituting 1,3-butanediol for equal amounts by weight of corn starch and dextrose


Analytical verification of doses or concentrations:
no
Details on mating procedure:
Investigation of teratogenicity was performed with part of the second litter of the F3 generation of a multigeneration study.


Duration of treatment / exposure:
day 0 to day 19 of gestation, additional to exposure of the parental (F2) and former generations (F0 and F1)
Frequency of treatment:
daily
Duration of test:
Part of multigeneration study
Doses / concentrations
Remarks:
0, 5, 10 and 24 % nominal in diet, corresponding to 0, 2500, 5000 and 12000 mg/kg bw/day, calculated with food factor 0.05 according to Guidance on Information Requirements R.8
No. of animals per sex per dose:
14-15 females per dose group
Control animals:
yes, plain diet

Examinations

Maternal examinations:
- sacrifice at day 19 of gestation
- number of implantations, resorptions, viable and nonviable fetuses
Fetal examinations:
- data on growth abnormalities, weight and sex of fetuses were recorded
- one third of fetuses were examined for soft tissue abnormalities and remaining fetuses were used for skeletal examinations
- soft tissue examinations: fetuses of each group were fixed in Bouin's solution, sectioned according to the method of Wilson and examined in detail for abnormalities
- skeletal examinations: fetuses were fixed in ethyl alcohol and stained with alizarin red and examined for defects
Statistics:
Skeletal tissue examinations: evaluated by the approximate chi-square test
Indices:
Fertility, gestation, gestation and lactation in remaining pups, not sacrificed for teratological examination

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
not specified
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Neuropathological findings:
not specified
Histopathological findings: neoplastic:
not specified

Maternal developmental toxicity

Number of abortions:
no effects observed
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:
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): not examined
Changes in number of pregnant:
no effects observed
Details on maternal toxic effects:
no effects observed

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
12 000 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Remarks on result:
other: dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

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

Details on embryotoxic / teratogenic effects:
- viability of pups, number of implantation and resorption sites and the mean fetal weight were unaffected by feeding diets with 1,3-butylene glycol up to 24% (12000 mg/kg bw/d), for details see below
- statistically significant increase of incomplete ossification of sternebrae for the middle and high level fetuses as compared with the control fetuses, and a statistically significant increase of missing sternebrae for high dose fetuses, for details see below

Effect levels (fetuses)

open allclose all
Key result
Dose descriptor:
NOAEL
Effect level:
12 000 mg/kg bw/day (nominal)
Basis for effect level:
other: teratogenicity
Remarks on result:
other: maternal dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Dose descriptor:
LOAEL
Effect level:
5 000 mg/kg bw/day (nominal)
Basis for effect level:
other: fetotoxicity
Remarks on result:
other: maternal dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)
Key result
Dose descriptor:
NOAEL
Effect level:
2 500 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: fetotoxicity
Remarks on result:
other: maternal dose calculated (24% in diet, food factor 0.05 according to Guidance on Information Requirements R.8)

Fetal abnormalities

Key result
Abnormalities:
effects observed, treatment-related
Localisation:
skeletal: sternum
Description (incidence and severity):
missing and incomplete ossification of sternebrae

Overall developmental toxicity

Key result
Developmental effects observed:
yes
Lowest effective dose / conc.:
5 000 mg/kg bw/day
Treatment related:
yes
Relation to maternal toxicity:
developmental effects in the absence of maternal toxicity effects
Dose response relationship:
yes
Relevant for humans:
yes

Any other information on results incl. tables

Conducted as part of reproduction study; no definitive
dose-related teratological findings in either soft or
skeletal tissue.  Fetotoxicity(e.g., delayed ossification of
sternebrae) noted at 10% and 24% doses, 5000 and 12000 mg/kg bw/d, respectively.

Incidence of fetal skeletal abnormalities in F3B generation:

            Dietary level (%)
   0  5  10  24
 No. of fetuses examined  124  103  120  103
 Sternebrae        
  Incomplete ossification  31  31  48*  65*
  Scrambled  1  0
  Bipartite  1  1  0  3
  Extra  1  0  0  0
  Missing  10  3  13  37**
 Ribs        
  More than 13  4  4  1  1
 Vertebrae        
  Incomplete ossification  4  1  1  2
  Scoliosis  1  0  0  0
 Skull        
  Incomplete closure  9  0  3  10
 Hyoid bone        
  Missing  2  0  0  2
  Reduced  0  0  0  1

*: significantly different from respective control, p </= 0.025

**: significantly different from respective control, p </= 0.01

Resorption and implantation data for F3B generation:

    Mean no. of pups per litter      
  Dietary level (%) No. of pregnant females  Viable Non-viable  Implantations (mean per dam) Resorptions(mean per dam) Mean fetal weight (g) 
 0  15  11.9  0  12.5  0.6  3.5
 5  15  10.1  0  10.4  0.3  4.0
 10  14  12.1  0  12.6  0.5  4.1
 24  14  10.9  0  11.4  0.5  3.4

Applicant's summary and conclusion

Conclusions:
No teratogenic effects were seen in rats treated with up to 24% (12000 mg/kg bw/d) 1,3-butylene glycol in the diet. But fetotoxic effects occurred in concentrations at or above 10% (5000 mg/kg bw/d) 1,3-butylene glycol in the diet.
Executive summary:

Teratogenic effects of 1,3-butylene glycol were investigated as part of a multigeneration study in rats receiving 0, 5, 10 and 24% 1,3-butylene glycol in the diet (0, 2500, 5000, 12000 mg/kg bw/d). No conclusive teratogenic effects were seen in pups of the F3B generation at levels up to 12000 mg/kg bw/d 1,3-butylene glycol in the diet. Incomplete sternebral ossification at mid- and high-dose levels and missing sternebrae at high-dose level were noted, probably indicating slight delayed development of fetal skeletal tissue. The NOAEL for fetotoxicity was 2500 mg/kg bw/d of 1,3-butylene glycol in the diet (Hess et al., 1981).