Butane-1,3-diol

Genetic toxicity: in vivo

Administrative data

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

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

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 for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

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 or test system 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).

Cross-reference 2

Reason / purpose for cross-reference:

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 for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

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 or test system 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

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	0	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).

Cross-reference 3

Reason / purpose for cross-reference:

reference to same study

Reference

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)

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to same study

Principles of method if other than guideline:

study on developmental toxicity

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Wistar

Details on test animals or test system 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

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

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

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

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

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

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)

Key result

Abnormalities:

no effects observed

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

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)

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

skeletal: sternum

Description (incidence and severity):

missing and incomplete ossification of sternebrae

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

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	0	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

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).

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

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

Test material

Test material information

Constituent 1

Reference substance name:

Butane-1,3-diol

EC Number:

203-529-7

EC Name:

Butane-1,3-diol

Cas Number:

107-88-0

Molecular formula:

C4H10O2

IUPAC Name:

butane-1,3-diol

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

Sex:

male/female

Details on test animals or test system 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

Administration / exposure

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

Doses / concentrations

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

Examinations

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.

Results and discussion

Test results

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).

Any other information on results incl. tables

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.

Applicant's summary and conclusion

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).

.