Dibutyl maleate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Based on the expected metabolism of diesters, n-butyl hydrogen maleate was selected as one of the most suitable read across substances for DBM, as it represents one of the metabolic/chemical breakdown products of DBM. For further information, please refer to Sect 13: " Updated Version Comprenhensive read across rationale for waiving further studies on reprodutive and developmental toxicity".

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Reference

Endpoint:

developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

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

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Justification for type of information:

Based on the expected metabolism of diesters, n-butyl hydrogen maleate was selected as one of the most suitable read across substances for DBM, as it represents one of the metabolic/chemical breakdown products of DBM. For further information, please refer to Sect 13: " Updated Version Comprenhensive read across rationale for waiving further studies on reprodutive and developmental toxicity".

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

other: Ministry of Health and Welfare, Japan; Guidelines for Toxicity Studies of Drugs

Principles of method if other than guideline:

Pregnant rats were given drinking water containing 1-butanol at 0.2%, 1.0% or 5.0% (316, 1454 or 5654 mg/kg/day) on days 0–20 of pregnancy. The rats were sacrificed on day 20 of pregnancy and both the dams and fetuses were examined.

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Tsukuba Breeding Center
- Age at study initiation: males: 10 weeks; females: 9 weeks
- Weight at study initiation: females: 217-273 g
- Housing: individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-25 °C
- Humidity (%): 40-70 %
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: drinking water

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
1-butanol was mixed with water to the according target concentrations. The stability of formulations in a dark and cool place under airtight conditions has been confirmed for up to 3 days. During use, the formulations were maintained under such conditions for no more than 3 days and were 95.7–103.5% of the target concentration.

Analytical verification of doses or concentrations:

yes

Details on mating procedure:

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

Duration of treatment / exposure:

day 0 through day 20 of pregnancy

Frequency of treatment:

continuous through drinking water

Duration of test:

until day 20 of pregnancy

No. of animals per sex per dose:

20 females per dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The dosage levels were determined based on the results of our range-finding study in which administration of 1-butanol in the drinking water on days 0–20 of pregnancy caused decreases in maternal body weight gain and food and water consumption and tended to reduce in fetal weight at 4% and 7% in rats.

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: not specified

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: not not specified

BODY WEIGHT: Yes
- Time schedule for examinations: once daily

FOOD CONSUMPTION: Yes
- Time schedule for examinations: every 3 or 4 days

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: daily

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 10
- Organs examined: not specified

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No data
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes: [half per litter]
- Skeletal examinations: Yes: [half per litter]
- Head examinations: Yes: [half per litter]

Statistics:

The statistical analysis of fetuses was carried out using the litter as the experimental unit. The initial body weight, body weight gain and food and water consumption of pregnant rats, numbers of corpora lutea, implantations and live fetuses per litter, fetal weight and crown-rump length and placental weight were analyzed with Bartlett's test for homogeneity of variance at the 5% level of significance.
If it was homogeneous, the data were analyzed using Dunnett's multiple comparison test to compare the mean of the control group with that of each dosage group, and if it was not homogeneous, the mean rank of the 1-butanol-treated groups was compared with that of the control group with the Dunnett type test. The Dunnett type test was used for the incidences of pre- and postimplantation embryonic loss and fetal anomalies and sex ratio of fetuses to compare the mean rank of groups treated with 1-butanol and that of the control group. The incidence of dams with anomalous fetuses was analyzed by Chi-square test or Fisher's exact test. The significance of differences from the control group was estimated at probability levels of 1% and 5%.

Indices:

no data

Historical control data:

International Genetic Standard (Crj: CD (SD) IGS) rats were used throughout this study. This strain was chosen because it is most commonly used in reproductive and developmental toxicity studies and historical control data are available.

Details on maternal toxic effects:

Details on maternal toxic effects:
No death was found in female rats of any group. All females in all groups became pregnant. The body weight gains on days 0–7 of pregnancy were significantly reduced at 5.0%. The body weight gain during the whole period of pregnancy was also significantly decreased at 5.0%. No significant decrease in the body weight gain was noted at 0.2 or 1.0, except for a transient decrease on days 0–2 of pregnancy at 1.0%. The food consumption on days 0–7, days 7–14, days 14–20 and days 0–20 of pregnancy was significantly lower in the 1.0% and 5.0% groups than the control group. The water consumption on days 0–7 at 1.0 and 5.0% and on days 7–14, days 14–20 and days 0–20 at 5.0% was significantly decreased. The mean daily intakes of 1-butanol were 316 mg/kg for the 0.2% group, 1454 mg/kg for the 1.0% group and 5654 mg/kg for the 5.0% group.

Dose descriptor:

NOAEL

Effect level:

1 454 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Details on embryotoxic / teratogenic effects:

Details on embryotoxic / teratogenic effects:
No litters totally resorbed were found in any group. No effects of the administration of 1-butanol were observed on the numbers of corpora lutea, implantations, pre- or postimplantation loss, resorptions or dead or live fetuses or sex ratio of live fetuses. The body weights of male and female fetuses were significantly lower in the 5.0% group than in the control group. There was no significant difference in the crown-rump length of male and female fetuses or placental weight between the control and groups treated with 1-butanol.
One fetus with spina bifida in the control group and one fetus with thread-like tail and anal atresia in the 0.2% group were observed. Skeletal examination revealed one fetus with supernumerary thoracic vertebral bodies and malpositioned thoracic vertebrae at 1.0%. Although the total number of fetuses with skeletal variations was significantly increased at 5.0%, the number of fetuses with individual skeletal variations was not significantly increased, except for fetuses with short supernumerary ribs at 5.0%. A significantly lower number of forepaw proximal phalanges was observed at 5.0%. Membranous ventricular septum defect occurred in one fetus of the control and 0.2% groups and 3 fetuses in 3 dams of the 5.0% group. One fetus with a double aorta in the control group and one fetus with a left umbilical artery in the control and 2.0% groups were observed. Thymic remnants in the neck were found in 4–11 fetuses of the control and groups treated with 1-butanol.
However, there was no significant difference in the incidence of fetuses with internal abnormalities between the control and groups treated with 1-butanol.

Dose descriptor:

NOAEL

Effect level:

5 654 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Dose descriptor:

NOAEL

Effect level:

1 454 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

Abnormalities:

not specified

Developmental effects observed:

not specified

Summary:

A significant decrease in maternal body weight gain accompanied by reduced food and water consumption was found at 5.0%. No significant increase in the incidence of pre- and postimplantation embryonic loss was observed in any groups treated with 1-butanol. Fetal weight was significantly lowered at 5.0%. Although a significant increase in the incidence of fetuses with skeletal variations and decreased degree of ossification was found at 5.0%, no increase in the incidence of fetuses with external, skeletal and internal abnormalities was detected in any groups treated with 1-butanol. The data demonstrate that 1-butanol is developmental toxic only at maternal toxic doses. No evidence for teratogenicity of 1-butanol was noted in rats. Based on the significant decreases in maternal body weight gain and fetal weight which NOAEL (maternal toxicity) was determined at 1454 mg/kg/day, it is concluded that the no observed adverse effect levels (NOAELs) of 1-butanol for both dams and fetuses are 1.0% (1454 mg/kg/day) in rats.

Data source

Reference

Reference Type:

publication

Title:

Teratology and multigeneration reproduction studies with maleic anhydride in rats

Author:

Short RD, Johannsen FR, Levinskas G J, Rodwell DE, Schardein JL

Year:

1986

Bibliographic source:

Fundam. Appl. Toxicol. 7: 359-366

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Maleic anhydride

EC Number:

203-571-6

EC Name:

Maleic anhydride

Cas Number:

108-31-6

Molecular formula:

C4H2O3

IUPAC Name:

furan-2,5-dione

Constituent 2

Reference substance name:

2,5-Furandione

IUPAC Name:

2,5-Furandione

Test material form:

other: briquettes

Details on test material:

- Name of test material (as cited in study report): Maleic anhydride
- Molecular formula (if other than submission substance): C4H2O3
- Molecular weight (if other than submission substance): 98.06 g/mol
- Smiles notation (if other than submission substance): O=C1OC(=O)C=C1
- InChl (if other than submission substance):
- Structural formula attached as image file (if other than submission substance): see Fig. 1
- Physical state: white solid (briquette)
- Analytical purity: >99%

Specific details on test material used for the study:

Test material was supplied by Monsanto Company as white briquettes with apurity greater tha 99%

Test animals

Species:

rat

Strain:

CD-1

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: approximately 12 weeks
- Housing: Besides mating and lactation, animals were housed individually.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: Animals were acclimated to for at least 10 days

ENVIRONMENTAL CONDITIONS
Animals were maintained in environmentally controlled rooms with a photoperiod of 12 hrs dark / 12 hrs light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

Ground maleic anhydride was suspended in corn oil. A 1% (w/v) concentration ws used to administer all doses.

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

- Impregnation procedure: cohoused
- M/F ratio per cage: 1/1
- Proof of pregnancy: vaginal plug or sperm in vaginal smear referred to as day 0 of pregnancy

Duration of treatment / exposure:

From day 6 to day 15 from gestation

Frequency of treatment:

Daily during day 6 and day 15 from gestation

Duration of test:

Animals were sacrificed on day 20 of gestation

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

30 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

90 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

140 mg/kg bw/day (nominal)

No. of animals per sex per dose:

25 mated females/dose group

Control animals:

yes, concurrent vehicle

Details on study design:

Doses were selected based on the results of a pilot study

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes

BODY WEIGHT: Yes

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

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Number of implantations: Yes
- Number of resorptions: Yes

Fetal examinations:

Fetuses were weighed and examined for external abnormalities, skeletal abnormalities, and abnormalities in the soft tissue.

Statistics:

Analysis of variance followed by Dunnett's test for adult body weights
Mann-Whitney U test for fetal body weights
chi square of Fisher's exact test for litters with anomalies
Level of significance: p<0.05

Historical control data:

not reported

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

mortality observed, non-treatment-related

Description (incidence):

Significant mortality occurred in male and female adults in the hig dose group.

Body weight and weight changes:

effects observed, non-treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not examined

Ophthalmological findings:

not specified

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not specified

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

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

Description (incidence and severity):

Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): no effects observed

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
The general appearance and behavior of rats were not altered by treatment. One adult died in each of the experimental groups, but the overall survival in these groups was 96%. Dams in the experimental groups either failed to gain weight or lost weight between day 6 and day 9 of gestation. However, this effect was reversible, and there were no statistically significant effects on body weight at any of the times examined.
Dams from all test groups produced normal-sized litters, and there was no evidence of postimplantation loss.

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

> 140 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Fetal body weights were slightly reduced for all test groups, compared with the control groups.However, the reductions were statistically significant only in the low- and high-dose groups. But this is not considered to be compound-related, because fetal weights for control and all treated groups were slightly greater than the values for historical controls. Malformations were observed in one fetus (one litter) from the control group, two fetuses (two litters) from the low-dose group, and three fetuses (three litters) from the high-dose group. Since each malformation was a single occurrence and the malformations differed among the various groups, there was no evidence of a dose-related increase in any specific malformation. The fetal variations were comparable both in type and frequency in the control and treated groups.

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

> 140 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

NOAEL

Effect level:

> 140 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Maleic anhydride is not teratogenic under the conditions of the present test.