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Diss Factsheets

Administrative data

Key value for chemical safety assessment

Toxic effect type:
dose-dependent

Effects on fertility

Description of key information

An EORGTS (OECD 443) is proposed (please refer to 7.8.1). In the supporting study, an OECD 422 guideline study, a NOAEL for reproductive toxicity was determined to be 800 mg/kg/day for parental and F1 animals (MHW, 1999).

Effect on fertility: via oral route
Endpoint conclusion:
no study available (further information necessary)
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

Supporting study:


In an OECD 422 guideline study, a NOAEL for reproductive toxicity was determined to be 800 mg/kg/day for parental and F1 animals (MHW, 1999). Male and female rats were given daily oral doses of 200, 400 and 800 mg/kg. In this study, the parental animals exhibited no alteration in reproductive parameters including the copulation index, fertility index, gestation length, numbers of corpora lutea or implantation, implantation index, gestation index, delivery index, and behavior at delivery and lactation. Although neither the pup viability nor the incidence of morphological abnormalities was changed by administration of the compound, pup body weight was slightly but significantly decreased in the 800 mg/kg group. This change was considered to be secondary to maternal toxicity (reduced food consumption and body weight gain).

Effects on developmental toxicity

Description of key information

Oral, mouse: NOAEL(maternal toxicity): 100 mg/kg bw/, NOAEL(fetotoxicity and teratogenicity): 600 mg/kg bw/d
Inhalation, rabbit (read across): NOAEC for maternal and for the fetal toxicity: 5.0 mg/L

Link to relevant study records

Referenceopen allclose all

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1992-03-16 to 1992-04-16
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
other: EPA-TSCA New and Revised Health Effects Test Guidelines [Developmental Toxicity Study]
Version / remarks:
1984
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: Commission directive 87/302/EEC for 9th adaption of directive 67/548/EEC, pages 24 - 26,1988 (fEC 1988)
Version / remarks:
1987-11-18
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Version / remarks:
12 May 1981
Deviations:
no
Remarks:
Yes, compared to current version (25 June 2018): number of dams: 15 instead of 20, inhalation route instead of requested oral route, however testing up to 5 mg/L, which is the acute limit concentration for aerosols.
GLP compliance:
yes (incl. QA statement)
Limit test:
no
Species:
rabbit
Strain:
Himalayan
Remarks:
Chbb:HM (outbred strain)
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Dr. K. Thomae GmbH, D-W7950 Biberach/Riss, FRG
- Age at study initiation: 18 - 26 weeks
- Weight at study initiation: Approx. 2.356 kg
- Housing: Singly in wire cages (type K 300/8, EBECO, Becker & Co., Castrop-Rauxel, FRG).
- Diet: Ad libitum (during the exposure-free observation period)
- Water: Ad libitum (during the exposure-free observation period)
- Acclimation period: At least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Air changes (per hr): Not indicated, but rooms were fully air-conditioned
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From March 25, 1992 to April 16, 1992
Route of administration:
other: inhalation: mix of vapour and aerosol
Type of inhalation exposure (if applicable):
whole body
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
2.4 µm
Details on exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Glass-steel inhalation chambers (manufacturer: BASF Aktiengesellschaft)
- Method of holding animals in test chamber: They were fixed in modified fixation cages wrapped with aluminium foil.
- Source and rate of air: See table 1 under "Any other information on materials and methods, incl. tables"
- Method of conditioning air: The test substance was supplied to a two-component atomizer by means of a continuous metering pump. By means of compressed air, the aerosol was generated into an aerosol mixing vessel. In the mixing vessel the aerosol was mixed with conditioned supply air and passed through a cyclonic separator into the inhalation chamber.
- Temperature, humidity, pressure in air chamber: 22-23.3 °C, rel. humidity 47.8-67.1 %, pressure [Pa]: test group 0: 10.2+/-0.3, test group 1: -10+/- 0.2, test group 2: -9.2+/- 1.3, test group 3: -6.8+/- 5.2
- Air flow rate: See table 1 under "Any other information on materials and methods, incl. tables"
- Method of particle size determination: The particle size analysis was carried out with a cascade impactor in test groups 2 and 3. One sample was taken from test group 2 and 3 respectively with a cascade impactor at a sampling velocity of 1.25 m/sec. In addition to the cascade impactor measurements, a laser photometer (Malvern API) was used for detection of aerosols.
- Treatment of exhaust air: The exhaust air system flow was set higher than the supply air system flow (negative pressure). This ensured that no contamination of the laboratory could occur due to any leakages from the inhalation chambers.

TEST ATMOSPHERE
- Brief description of analytical method used: The concentrations of the test atmospheres were analysed by gas chromatography after absorption into 2-propanol. The gas chromatograph was calibrated with weighed amounts of the test substance.
- Samples taken from breathing zone: The samples were taken from the exposure chambers, from the breathing zones of the animals.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The concentrations of the test atmospheres were analyzed by gas chromatography after absorption into 2-propanol. The gas chromatograph was calibrated with weighed amounts of the test substance.
Details on mating procedure:
- Impregnation procedure: artificial insemination
0.2 mL of a synthetic hormone which releases LH and FSH from the anterior pituitary lobe (Reeeptal®, trademark of HOECHST AG, Frankfurt/Main) were injected intramuscularly to the female rabbits about 1 hour before insemination. The pooled ejaculate samples used for the artificial insemination were derived from male Himalayan rabbits of the same breed as the females. The male donors were kept under conditions (air conditioning, diet, water) comparable to those of the females participating in this study.
- The day of insemination was designated as day 0 (beginning of the study) and the following day as day 1 post insemination (p.i.).
Duration of treatment / exposure:
From day 7 to day 19
Frequency of treatment:
Daily for 6 hours
Duration of test:
From day 0 (day of insemination) to day 29 (day of sacrifice)
Dose / conc.:
5 mg/L air (nominal)
Dose / conc.:
1.4 mg/L air (nominal)
Dose / conc.:
0.5 mg/L air (nominal)
Dose / conc.:
0 mg/L air (nominal)
Remarks:
Control (fresh air)
No. of animals per sex per dose:
15 female animals per dose (divided into 3 replicates - 3x5 animals per dose)
Control animals:
yes, concurrent no treatment
Details on study design:
- Dose selection rationale: The doses were selected based on a dose-range finding study where no adverse treatment-related effects occured up to the limit dose of 5 mg/L.
- Rationale for animal assignment: Animals were allocated to the test groups according to a computergenerated randomization plan on the basis of their body weights.

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: The behavior and state of health of the test animals were checked each day at least 3 times on exposure days and, as a rule, once during the preflow period and the post-exposure observation period.

BODY WEIGHT: Yes
- Time schedule for examinations: The body weight of the animals was checked on day 0 (= day of insemination) and on days 3, 7, 10, 13, 16, 19, 21, 24, 27 and 29 p.i..

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on day 29 p.i.
- Organs examined: ovaries and uterine content (see below)
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
- Other: dead fetuses
Fetal examinations:
- External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes: [all per litter ]
- Skeletal examinations: Yes: [all per litter]
- Head examinations: Yes: [all per litter]
Statistics:
Examination of the dams and fetuses
DUNNETT's Test (DUNNETT, 1955, 1964) was used for statistical evaluation of body weight, body weight change, corrected body weight gain (net matern al body weight change), weight of the uterus before it was opened, weight of fetuses, weight of placentae, corpora lutea, implantations, pre- and postimplantation losses, resorptions and live fetuses.
FISHER's Exact Test (SIEGEL, 1956) was used for statistical evaluation of conception rate, mortality (of the dams) and all fetal findings.
Significances resulting from these tests have been indicated in the tables (a for p < 0.05, b for p < 0.01).
Indices:
conception rate and pre- and postimplantation losses
Historical control data:
Historical control data are available for the maternal body weights and reporduction data including fetal weights and fetal examinations.
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Description (incidence and severity):
The body weight and body weight change of the test groups, compared with the control group, was not influenced in a statistically significant manner over the study period.
Gross pathological findings:
effects observed, non-treatment-related
Description (incidence and severity):
At necropsy none of the does of test groups 1 - 3 (0.5, 1.4 and 5.0 mg/L) showed any substance-induced findings. One spontaneous necropsy finding was recorded for single animals of all dose groups including the controls. This finding, lungs with edema, has to be related to the sacrifice of the animals.
Lungs with edema in test group 0 (control): 5 (33 %), test group 1 (0.5 mg/L): 4 (27 %), test group 2 ( 1.4 mg/L): 5 (33 %), test group 4 ( 5 mg/L): 2 (13 %).
Number of abortions:
no effects observed
Pre- and post-implantation loss:
effects observed, non-treatment-related
Description (incidence and severity):
There were no substance-related and/or statistically significant differences 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 differences evident are considered to be incidental and within the normal range of deviations for animals of this strain and age.
Total litter losses by resorption:
no effects observed
Early or late resorptions:
effects observed, non-treatment-related
Description (incidence and severity):
The differences evident are considered to be incidental and within the normal range of deviations for animals of this strain and age.
test group 0 (0 mg/L): 5 resorptions (4.7 % +/- 7.12)
test group 1 (0.5 mg/L): 10 resorptions (9.5 % +/- 16.9)
test group 2 (1.4 mg/L): 11 resorptions (10.5 % +/- 12.67)
test group 3 (5 mg/L): 11 resorptions (8.3 % +/- 11.71)
Dead fetuses:
no effects observed
Changes in pregnancy duration:
no effects observed
Changes in number of pregnant:
no effects observed
Details on maternal toxic effects:
The conception rate was 100% in all groups. Concerning all groups, there were no substance-related and/or statistically significant differences 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. The differences evident are considered to be incidental and within the normal range of deviations for animals of this strain and age.
Key result
Dose descriptor:
NOAEC
Effect level:
5 mg/L air
Based on:
test mat.
Basis for effect level:
other: absence of adverse effects
Remarks on result:
other: no adverse effects
Key result
Abnormalities:
no effects observed
Fetal body weight changes:
no effects observed
Reduction in number of live offspring:
no effects observed
Changes in sex ratio:
effects observed, non-treatment-related
Description (incidence and severity):
The sex distribution of the fetuses in test groups 1 - 3 (0.5; 1.4 and 5.0 mg/L) was comparable with the control fetuses. The differences observed in comparison to the control are without any biological relevance.
Changes in litter size and weights:
no effects observed
External malformations:
effects observed, non-treatment-related
Description (incidence and severity):
Only one type of external variation (pseudoankylosis) was found in one control and three high concentration fetuses; however, all values concerning fetal and litter incidences are fully in the historical control range and the differences between the groups are therefore considered random.
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
Malformations of the fetal skeletons were recorded for one fetus of the control group (different thoracic vertebral bodies and/or arches severely malformed), one fetus of the 0.5 mg/L group and two fetuses of the 1.4 mg/L group (lumbar vertebra absent) and one 5.0 mg/L fetus (different cervieal vertebral bodies and/or arches severely malformed). The variations elicited were related to the skull (splitting of skull bones, epactal bone between nasal and frontal bones), the ribs (accessory 13th rib(s)), the vertebral column (accessory thoracic or lumbar vertebra) and the sternum (sternebra(e) of irregular shape, fused or accessory sternebra). All of these skeletal variations were found in single fetuses of all groups including the controls, occurred without a clear dose-response relationship, without any biologically relevant differences between the groups, and/or can be found at comparable fetal/litter incidences in the historical control. This includes the statistically significantly higher values concerning the finding epactal bone between nasal and frontal bones and the statistically significantly lower values concerning the finding sternebra(e) of irregular shape in the 1.4 mg/L group. Moreover, the lower number of low dose fetuses with total skeletal variations is considered random. In all groups signs of retardations (incomplete or missing ossification of skull bones, vertebral column, os pubis, talus and/or sternebra(e)) were found; they occurred in a comparable frequency in the control and the substance-treated groups. All differences between the groups concerning fetal skeletal retardations are without any biological relevance. This includes the marginally, but statistically significant higher incidence of total skeletal retardations at 0.5 mg/L.
The number of 0.5 mg/L fetuses with skeletal variations is statistically significantly lower in comparison to the actual control group; in the same test group the occurrance of skeletal retardations is statistically significantly higher in comparison to the control group. Both, the lower incidence of skeletal variations and the higher incidence of skeletal retardations in the 0.5 mg/L group, however, are considered random because the relevant values recorded for this group are fully in the range of the historical control data and no dose-response relationship exists.
Visceral malformations:
effects observed, non-treatment-related
Description (incidence and severity):
Soft tissue malformations occurred in all groups including the controls without any relation to the treatment. One low dose fetus showed hydrocephaly. Septal defect occurred in one control and one intermediate dose fetus each and 2 low dose fetuses. Hypoplastic lungs were found in 2 intermediate dose fetuses; in one of these fetuses it was associated with a diaphragmatic hernia. Moreover a hypoplastic spleen was recorded for one low dose and agenesia of gallbladder for one control, one 1.4 and one 5.0 mg/L fetus. Due to the fact that no dose-relationship exists and nearly all above mentioned soft tissue mal formations can be found at a low frequency in the historical control data, these malformations are regarded as being of spontaneous origin and not associated with the test substance exposure of the does. Variations were detected in each group including the control, all occurred without a clear dose-response relationship and/or can be found at a comparable incidence in the historical control data. Aside from a separated origin of carotids, a very common finding in the rabbit strain used, another soft tissue variation (heart with traces of interventricular foramen/septum membranaceum) was also found quite frequently. Furthermore, one fetus of the high dose group (5.0 mg/L) exhibited hypoplasia of gallbladder. One control and one intermediate dose fetus showed a so-called unclassified observation (focal liver necrosis). Blood coagulum around the bladder was seen in one high dose fetus.
There are only very few statistically significant differences between the control and the test substance exposed fetuses concerning soft tissue variations. The variation rate is not increased in the fetuses of the substance-exposed groups in comparison to the control group. All differences between the groups are without any biological relevance, do not show a clear dose-response relationship and/or appear to about the same extent in the historical control data.
Details on embryotoxic / teratogenic effects:
The malformation rate is not increased in the fetuses of the substance-exposed groups in comparison to the control group. All differences between the groups are without any biological relevance. The number of 0.5 mg/L fetuses with skeletal and total variations is statistically significantly lower in comparison to the actual control group; in the same test group the occurrance of skeletal (and consequently total) retardations is statistically significantly higher in comparison to the control group. Both, the lower incidence of skeletal and overall variations and the higher incidence of skeletal and overall retardations in the 0.5 mg/L group, however, are considered random because the relevant values recorded for this group are fully in the range of the historical control data and no dose-response relationship exists. For all other differences between the actual control group and the substance-exposed groups concerning fetal external, soft tissue and/or skeletal observations it can be said, that their occurrence is without any biological relevance, do not show a clear dose-response relationship and/or appear to about the same extent in the historical control data.
Key result
Dose descriptor:
NOAEC
Effect level:
5 mg/L air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other:
Remarks on result:
other: no adverse effects
Key result
Abnormalities:
effects observed, non-treatment-related
Localisation:
skeletal: skull
skeletal: sternum
skeletal: supernumerary rib
skeletal: vertebra
other: Soft tissue malformations occured in all groups including the control without relation to treatment
Description (incidence and severity):
The malformation rate is not increased in the fetuses of the substance-exposed groups in comparison to the control group. All differences between the groups are without any biological relevance. The number of 0.5 mg/L fetuses with skeletal and total variations is statistically significantly lower in comparison to the actual control group; in the same test group the occurrance of skeletal (and consequently total) retardations is statistically significantly higher in comparison to the control group. Both, the lower incidence of skeletal and overall variations and the higher incidence of skeletal and overall retardations in the 0.5 mg/L group, however, are considered random because the relevant values recorded for this group are fully in the range of the historical control data and no dose-response relationship exists. For all other differences between the actual control group and the substance-exposed groups concerning fetal external, soft tissue and/or skeletal observations it can be said, that their occurrence is without any biological relevance, do not show a clear dose-response relationship and/or appear to about the same extent in the historical control data.
Key result
Developmental effects observed:
no

There were no substantial, substance-related effects on the dams concerning body weight, body weight change, uterine weights, corrected body weight change, clinical and necropsy observations up to and including concentration of 5 mg/L. There were no differences of biological relevance between the control and the substance-treated groups in conception rate, mean number of corpora lutea, total implantations, resorptions and live fetuses, fetal sex ratio or in the values calculated for the pre-and the postimplantation losses. No concentration- and/or substance-related differences were recorded for placental and fetal body weights. The external, soft tissue and/or skeletal examination of the fetuses revealed no differences. between the control and the substance-treated groups which might be related to the test substance administration. Number and type of the fetal external, soft tissue and skeletal findings, which were classified as malformations, variations and/or retardations, recorded for the 0.5; 1.4 and 5.0 mg/L fetuses were substantially similar to actual and/or historical control values. Thus, under the conditions of this study, 1-Butyrolacton caused no signs of maternal toxicity and no signs of embryo-/fetotoxicity up to and including a concentration of 5 mg/L. There were no indications of teratogenic effects which could be causally related to the test substance administration. Although no signs of matern al toxicity were found even at the highest concentration (5 mg/L), no further prenatal inhalation toxicity studies are deemed to be necessary, because this concentration is in accordance with the requirement for the LIMIT TEST, e.g. in the OECD Guideline for testing of chemicals No. 403 (OECD 1981) for acute inhalation studies and the EPA-TSCA guideline “Inhalation developmental toxicity study” § 798.4350 (EPA 1984). For this prenatal toxicity study in rabbits, the no observed adverse effect concentration (NOAEC) for the maternal and for the fetal organism is 5.0 mg/L.

Conclusions:
For this prenatal toxicity study in rabbits, the no observed adverse effect concentration (NOAEC) for the maternal and for the fetal organism is 5.0 mg/L.
Executive summary:

1-Butyrolactone was tested for its prenatal inhalation toxicity in rabbits. Groups of 15 inseminated female Himalayan rabbits were exposed to clean air (control) or 1-Butyrolacton vapour and vapour-aerosol-mixtures (test groups) for 6 hours/day on days 7 to 19 post insemination (p.i.). The target concentrations for the study were set to 0.5 (vapour), 1.4 and 5.0 mg/L (vapour-aerosol-mixture). The animals were treated in whole body inhalation chambers, sitting in specially shielded cages to avoid contamination of body surface (head-nose exposure). Clinical examination of the animals was performed at least once daily in the pre- and post-exposure period. In the treatment interval the health of the animals was checked before, during and after exposure. Body weight development was followed throughout the study. On day 29 p.i. all animals were sacrificed and the uteri removed. The fetuses were dissected from the uteri, sexed, weighed and examined for any external, soft tissue and skeletal findings.


Analyses of the atmospheres demonstrated that the target concentrations were fully met. Particle size measurement revealed the presence of aerosols at 5.0 mg/L with an MMAD of 2.4 µm and a respirable fraction of 92%. There were no substantial, substance-related effects on the dams concerning body weight, body weight change, uterine weights, corrected body weight change, clinical and necropsy observations up to and including concentration of 5 mg/L. There were no differences of biological relevance between the control and the substance-treated groups in conception rate, mean number of corpora lutea, total implantations, resorptions and live fetuses, fetal sex ratio or in the values calculated for the pre-and the postimplantation losses. No concentration- and/or substance-related differences were recorded for placental and fetal body weights. The external, soft tissue and/or skeletal examination of the fetuses revealed no differences between the control and the substance-treated groups which might be related to the test substance administration. Number and type of the fetal external, soft tissue and skeletal findings, which were classified as malformations, variations and/or retardations, recorded for the 0.5; 1.4 and 5.0 mg/L fetuses were substantially similar to actual and/or historical control values. Thus, under the conditions of this study, 1-Butyrolacton caused no signs of maternal toxicity and no signs of embryo-/fetotoxicity up to and including a concentration of 5 mg/L. There were no indications of teratogenic effects which could be causally related to the test substance administration.


Although no signs of maternal toxicity were found even at the highest concentration (5 mg/L), no further prenatal inhalation toxicity studies are deemed to be necessary, because this concentration is in accordance with the requirement for the LIMIT TEST, e.g. in the OECD Guideline for testing of chemicals No. 403 (OECD 1981) for acute inhalation studies and the EPA-TSCA guideline "Inhalation developmental toxicity study" § 798.4350 (EPA 1984). For this prenatal toxicity study in rabbits, the no observed adverse effect concentration (NOAEC) for the maternal and for the fetal organism is 5.0 mg/L.

Endpoint:
developmental toxicity
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
For justification of read-across, please refer to IUCLID6 section 13.
Reason / purpose for cross-reference:
read-across source
Species:
rabbit
Strain:
Himalayan
Remarks:
Chbb:HM (outbred strain)
Key result
Dose descriptor:
NOAEC
Effect level:
5 mg/L air
Based on:
test mat.
Basis for effect level:
other:
Remarks on result:
other: no adverse effects
Key result
Abnormalities:
no effects observed
Key result
Dose descriptor:
NOAEC
Effect level:
5 mg/L air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: absence of adverse effects
Remarks on result:
other: no adverse effects
Key result
Abnormalities:
effects observed, non-treatment-related
Localisation:
skeletal: skull
skeletal: sternum
skeletal: supernumerary rib
skeletal: vertebra
other: Soft tissue malformations occured in all groups including the control without relation to treatment
Description (incidence and severity):
The malformation rate is not increased in the fetuses of the substance-exposed groups in comparison to the control group. All differences between the groups are without any biological relevance. The number of 0.5 mg/L fetuses with skeletal and total variations is statistically significantly lower in comparison to the actual control group; in the same test group the occurrance of skeletal (and consequently total) retardations is statistically significantly higher in comparison to the control group. Both, the lower incidence of skeletal and overall variations and the higher incidence of skeletal and overall retardations in the 0.5 mg/L group, however, are considered random because the relevant values recorded for this group are fully in the range of the historical control data and no dose-response relationship exists. For all other differences between the actual control group and the substance-exposed groups concerning fetal external, soft tissue and/or skeletal observations it can be said, that their occurrence is without any biological relevance, do not show a clear dose-response relationship and/or appear to about the same extent in the historical control data.
Key result
Developmental effects observed:
no
Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well-documented, guideline-like study report
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Version / remarks:
12 May 1981
Deviations:
no
Remarks:
Yes, compared to current version (25 June 2018): preferred rodent species: rat. Number of dams per group: 32 instead of 25. Parameters like maternal thyroid gland parameters and fetal AGD will be examined in the proposed OECD TG 443.
GLP compliance:
yes
Remarks:
testing lab.
Species:
mouse
Strain:
Swiss
Details on test animals or test system and environmental conditions:
Female outbred Swiss albino mice (CD-1 mice) (Charles River Laboratories, Inc., Raleigh, NC) were individually identified by tail tattoo. Male breeders of the same strain (Charles River Laboratories, Inc., Raleigh . NC) were individually identified by eartag. Plug-positive females were individually housed in solid-bottom polycartonate cages with stainless steel wire lids (Laboratory Products, Rochelle Park, NJ) and Ab-Sorb-Orig cage litter (Laboratory Products, Garfield, NJ). Ground Purina Certified Rodent Chow and deionized/filtered water were available ad libitum throughout gestation. Lights in the animal rooms were on from 07.00h to 19.00h. Environmental conditions (temperature and relative humidity) were monitored and controlled by computer. The average temperature was 72°F (range 69-75°F), and the average relative humidity was 55% (range 44-64%).
Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
Timed-mated mice were given 1.4-butanediol in aqueous solution on the mornings of gestational days 6 through 15. Analysis of dose formulations by gas chromatography prior to use indicated that formulations were within 97-105% of their theoretical concentrations. Dose formulations were stored at room temperature in amber glass containers, and used within the period of proven stability for these storage conditions. Treatment and examination of animals was performed without knowledge of dose levels.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Aqueous solutions of 1.4-butanediol (10 mg/ml) were stable for 28 days at room temperature when stored in the dark and were also stable under simulated conditions of use (ie. in an open beaker at room temperature when exposed to light and air in a laboratory hood tor 3 hours.
Details on mating procedure:
After a seven-day quarantine period, individual breeding pairs were cohabited overnight. The morning of vaginal plug detection was designated as gestational day (gd) 0. On gd 0, plug-positive females were assigned to experimental groups by stratified randomization so that body weights did not differ among groups within any individual replicate. The study was performed in two replicates with 4 consecutive breeding dates in each replicate. The last breeding date for the first replicate and the first breeding date for the second replicate were 18 days apart. The body weight range for females on gd
0 was 24-31 g.
Duration of treatment / exposure:
gd 6 through 15
Frequency of treatment:
daily
Duration of test:
until gd 17
Remarks:
Doses / Concentrations:
0 (control), 100, 300 or 600 mg/kg/day
Basis:

No. of animals per sex per dose:
32
Control animals:
yes, concurrent no treatment
Details on study design:
In a dose range-finding study, Swiss mice were exposed to 1.4-butanediol (0, 100, 400, 600, 800 or 1000 mg/kg/day p.o. on gd 6-15; 8 pregnancies/group). At 100 mg/kg/day, dams were alert, but slightly less active than controls. Maternal toxicity was expressed as reversible maternal sedation (ie. diminished activity followed by recumbancy or immobility) at 2400 mg/kg/day, and as reduced corrected gestational weight gain at >600 mg/kg/day. Gravid uterine weight (gd 17) appeared lower and prenatal mortality appeared to be higher than controls at 1400 mg/kg/day, but these differences were not statistically significant. Fetal body weight was significantly reduced relative to controls at >800 mg/kg/day.
Based upon the dose range finding study described above, dose levels of 0 (control), 100, 300 or 600 mg/kg/day were selected for the present study. The low dose was expected to be pharmacologically active (ie. mild maternal sedation), but to produce no other maternal or developmental effects. The mid dose was expected to produce moderate, reversible maternal sedation (<4 hours duration) and possible reductions in fetal body weight and prenatal viability. The high dose was expected to produce reversible maternal sedation (<4 hours duration), reduction of maternal body weight gain (gestation and corrected), possible changes in maternal hepatic or renal histology, and possible reduction in fetal body weight and prenatal viability.
Maternal examinations:
Timed-mated females were weighed in life on the mornings of gd 0, 3, 6-15 and 17. On treatment days (gd 6-15), each animal was observed for clinical signs of toxicity as follows: immediately before treatment, approximately 45-60 minutes after treatment and approximately 4 hours after treatment. On gd 16 and 17, each animal was observed for clinical signs of toxicity once in the morning. The times of observation and dosing were recorded for each animal. Measurements of food and water were taken on gd 0, 3, 6, 9, 12, 15, and 17. Animals were killed by cervical dislocation on gd 17.
At necropsy on gd 17, the maternal body, liver, kidneys and intact uterus were weighed and corpora lutea were counted. Maternal livers and kidneys were fixed in neutral buffered 10% formalin and saved for optional histopatholgy.
At necropsy on gd 17, uterine contents were examined to determine the number of implantation sites, resorptions, dead fetuses and live fetuses, uteri
which had no visible implantation sites were stained with ammonium sulfide (10%) to detect very early resorptions (Salewski,1964).
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:
On gd 17, live fetuses were dissected from the uterus and anesthetized on ice (Blair, 1971; Lumb and Jones, 1973). They were weighed, examined for
external morphological abnormalities and dissected for visceral examination by a fresh tissue dissection technique (Staples, 1974; Stuckhardt and Poppe, 1984). Half of the fetuses were decapitated prior to dissection; the heads were fixed in Bouin's solution and then examined by a free-hand sectioning technique (Wilson, 1965). All fetal carcasses (50% without heads) were stained with Alcian Blue/Alizarin Red S and examined for skeletal malformations (Marr et al., 1988).
Statistics:
yes
Historical control data:
yes
Details on maternal toxic effects:
Details on maternal toxic effects:
There were no maternal deaths in this study. No maternal or developmental effects were observed at the low dose. Dams (60-100 %/group/day) at the mid and high doses exhibited signs of central nervous system intoxication (hypoactivity, immobility, loss of righting reflex and/or prone posture) during the first 4 hr following daily administration. Maternal effects at the mid and high doses also included reduced food intake (treatment and post treatment periods), reduced body weight, and reduced weight gain (treatment period, gestation period and corrected weight gain).
Key result
Dose descriptor:
NOAEL
Effect level:
100 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Key result
Dose descriptor:
LOAEL
Effect level:
300 mg/kg bw/day
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Key result
Abnormalities:
no effects observed
Details on embryotoxic / teratogenic effects:
Details on embryotoxic / teratogenic effects:
The only definitive expression of developmental toxicity was a reduction in average fetal body weight at the middle and high doses (92% and 83% of control weight, respectively) .
Key result
Dose descriptor:
NOAEL
Effect level:
100 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: fetotoxicity
Key result
Dose descriptor:
LOAEL
Effect level:
300 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: fetotoxicity
Key result
Abnormalities:
no effects observed
Key result
Developmental effects observed:
no
Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
600 mg/kg bw/day
Study duration:
subacute
Species:
mouse
Quality of whole database:
reliable and well documented study, according to NTP protocol, suitable for assessment under REACH
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
5 mg/L
Study duration:
subacute
Experimental exposure time per week (hours/week):
42
Species:
rabbit
Quality of whole database:
OECD Guideline study, suitable for assessment
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available
Additional information

Two developmental toxicity studies are available which were considered suitable and reliable to be used as key studies.


The first key study is a developmental toxicity study reported by NTP (1994). The assay was conducted with mice and the test item was administered orally via gavage. Water served as vehicle. The test concentrations were 100, 300 or 600 mg/kg bw and the test animals were dosed daily from gestational day (g.d.) 6 until g.d. 15. No maternal or developmental effects were observed at the low dose. Dams (60-100 %/group/day) at the mid and high doses exhibited symptoms of central nervous system intoxication (hypoactivity, immobility, loss of righting reflex and/or prone posture) during the first 4 hr following daily administration. Maternal effects at the mid and high doses also included reduced food intake (treatment and post treatment periods), reduced body weight, and reduced weight gain (treatment period, gestation period and corrected weight gain). The only definitive expression of developmental toxicity was a reduction in average fetal body weight at the middle and high doses (92% and 83% of control weight, respectively). However, these lower fetal body weights appeared together with the reduced maternal body weights in the middle and high dose group. No fetal abnormalities regarding external, skeletal or soft tissue observations were found and no signs of developmental toxicity were detected. The NOAEL for maternal toxicity was determined to be 100 mg/kg bw/d based on reduced food consumption and body weights. The NOAEL for fetotoxicity and teratogenicity was found to be 600 mg/kg bw/d.


The second key study was conducted in rabbits to cover the developmental toxicity-testing in a non-rodent species:


The study was conducted with the read-across substance γ-butyrolactone (CAS 96-48-0) (BG Chemie, 1993).  1-Butyrolactone was tested for its prenatal inhalation toxicity. Groups of 15 inseminated female Himalayan rabbits were exposed to clean air (control) or 1-Butyrolacton vapour and vapour-aerosol-mixtures (test groups) for 6 hours/day on days 7 to 19 post insemination (p.i.). The target concentrations for the study were set to 0.5 (vapour), 1.4 and 5.0 mg/L (vapour-aerosol-mixture). The animals were treated in whole body inhalation chambers. Clinical examination of the animals was performed at least once daily in the pre- and post-exposure period. In the treatment interval the health of the animals was checked before, during and after exposure. Body weight development was followed throughout the study. On day 29 p.i. all animals were sacrificed and the uteri removed. The fetuses were dissected from the uteri, sexed, weighed and examined for any external, soft tissue and skeletal findings. There were no substantial, substance-related effects on the dams concerning body weight, body weight change, uterine weights, corrected body weight change, clinical and necropsy observations up to and including concentration of 5 mg/L. There were no differences of biological relevance between the control and the substance-treated groups in conception rate, mean number of corpora lutea, total implantations, resorptions and live fetuses, fetal sex ratio or in the values calculated for the pre-and the postimplantation losses. No concentration- and/or substance-related differences were recorded for placental and fetal body weights. The external, soft tissue and/or skeletal examination of the fetuses revealed no differences between the control and the substance-treated groups which might be related to the test substance administration. Number and type of the fetal external, soft tissue and skeletal findings, which were classified as malformations, variations and/or retardations, recorded for the 0.5; 1.4 and 5.0 mg/L fetuses were substantially similar to actual and/or historical control values. Thus, under the conditions of this study, 1-Butyrolacton caused no signs of maternal toxicity and no signs of embryo-/fetotoxicity up to and including a concentration of 5 mg/L. There were no indications of teratogenic effects which could be causally related to the test substance administration. Although no signs of maternal toxicity were found even at the highest concentration (5 mg/L), no further prenatal inhalation toxicity studies are deemed to be necessary, because this concentration is in accordance with the requirement for the LIMIT TEST, e.g. in the OECD Guideline for testing of chemicals No. 403 (OECD 1981) for acute inhalation studies and the EPA-TSCA guideline "Inhalation developmental toxicity study" § 798.4350 (EPA 1984). For this prenatal toxicity study in rabbits, the no observed adverse effect concentration (NOAEC) for the maternal and for the fetal organism is 5.0 mg/L.


Furthermore, two supporting studies are available:


In an OECD 422 guideline study, a slight but significant decrease in body weights of pups at day 4 of lactation was observed at 800 mg/kg bw (Japan MHW, 1999). Male and female rats were exposed daily (males 42 days, females 14 days prior to gestation to 3 days after lactation) by oral gavage to 200, 400, and 800 mg/kg-bw. The NOAEL for maternal toxicity was determined to 200 mg/kg bw/d and the NOAEL for fetal toxicity was determined to be 400 mg/kg bw/d, based on the decrease in body weights of pups which was considered secondary to maternal toxicity.


In an OECD 414 guideline study (Kronevi et al., 1988) with a supporting substance ( γ-butyrolactone, CAS 96-48-0) which, like 1,4-butanediol, rapidly metabolizes to γ-hydroxybutyric acid (GHB), there were no indications of teratogenic effects which were related to the test substance administered by oral gavage to rats up to 500 mg/kg-bw (Doses 0, 10, 50, 125, and 500 mg/kg/day).

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008
Based on the available data, the test item does not require classification for reproduction toxicity according to Regulation (EC) No 1272/2008 (CLP), as amended for the seventeenth time in Regulation (EU) No 2021/849.

Additional information