Reaction mass of 1,3-dioxan-5-ol and 1,3-dioxolan-4-ylmethanol

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1981; 01-07 to 01-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP lab following strict internal protocols

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

glycerol formal

IUPAC Name:

glycerol formal

Details on test material:

Purity >99%

Test animals

Species:

rat

Strain:

other: Charles River CRCD

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Wilmington, Massachusetts
- Age at study initiation: 12 to 13 weeks
- Weight at study initiation: 217 to 281 g
- Fasting period before study: not specified
- Housing: Following identification of mating, females were housed in stainless steel cages up to 3 per cage
- Diet (e.g. ad libitum): Purina Certified Rodent Chow #5002 ad libitum
- Water (e.g. ad libitum): tap water was available ad libitum
- Acclimation period: not specified

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 72°F
- Humidity (%): not specified
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): 12-12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): fresh daily preparation prior to dosing

VEHICLE
- Amount of vehicle (if gavage): 5ml/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

The stability and concentration of the GF dosing olutions were confirmed by chemical analysis

Details on mating procedure:

- Impregnation procedure: cohoused
- 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:

Days 6 through 17 of gestation

Frequency of treatment:

Once daily

Duration of test:

Sacrifice of the females on Day 20 of gestation

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
75
Basis:
nominal conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
150
Basis:
nominal conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
300
Basis:
nominal conc.

Doses / concentrations 4

Remarks:

Doses / Concentrations:
600
Basis:
nominal conc.

No. of animals per sex per dose:

25 in all treatment groups; 24 in control group

Control animals:

yes, concurrent no treatment

Examinations

Maternal examinations:

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: At dosing and 1 to 4 hours following dosing except on the weekends when clinical signs were recorded only at the time of dosing

BODY WEIGHT: Yes
- Time schedule for examinations: Days 0, 6, 8, 10, 12, 14, 16, 18 and 20 of gestation

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:
- Gravid uterus weight: No
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Visceral examinations: Yes: one third per litter and all dead and externally malformed fetuses
- Skeletal examinations: Yes: all per litter
- Head examinations: Yes: Heads of fetuses that were given routine visceral examination were fixed in Bouin's solution and examined by freehand serial sections

Statistics:

Data was examined for homogeneity of variance using the Levene Test and for normality using the Wilk and Shapiro W statistic. Significance at P = 0.05 was based on analysis of variance using a least significant difference procedure; normalizing for nonparametric data when necessary. The average live fetal weight per litter was adjusted for the time of sacrifice by covariance analysis.

Indices:

Maternal body weight changes
Number of live fetuses per litter
Number of resorptions/number of implants per female
Number of implants/female
Number of dead fetuses/number of live fetuses
Average live fetal weight per litter
Percent preimplantation loss

Historical control data:

Incidence of wavy ribs among rats in historical control groups is as followed:

Study A
No. Fetuses examined: 506; No. litters examined: 38; No. malformed fetuses: 14; No. litters with malformations: 6(16%)

Study B
No. Fetuses examined: 496; No. litters examined: 39; No. malformed fetuses: 20; No. litters with malformations: 10(25%)

Study C
No. Fetuses examined: 514; No. litters examined: 39; No. malformed fetuses: 18; No. litters with malformations: 6(15%)

Study D
No. Fetuses examined: 261; No. litters examined: 20; No. malformed fetuses: 6; No. litters with malformations: 6(30%)

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
There were no clinical signs of toxicity among females in any of the treatment groups.
GF had no adverse effect on maternal body weight gain.

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

> 600 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

body weight and weight gain

Remarks on result:

not determinable due to absence of adverse toxic effects

Maternal abnormalities

Abnormalities:

no effects observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
There was a significant (P ≤ 0.05) increase in the numbers of dead and resorbed fetuses and a corresponding decrease in the number of live fetuses per litter in females from the 600 mg/kg/day dosage level group. No other adverse effects on reproductive status occured in any of the remaining dosage groups. There were dose-related statistically significant (P ≤ 0.05) decreases in average live fetal weight per litter in fetuses from dams administrated 150, 300 and 600 mg/kg/day of GF. There was no adverse effect on average live fetal weight inn fetuses from the 75 mg/kg/day dosage level group. There was a treatment-related incidence of anal atresia and tail malformations among fetuses from dams administrated 300 and 600 mg/kg/day of GF, and anasarca in fetuses from the 600 mg/kg/day group. There were no treatment-related external malformations in fetuses from the 78 and 150 mg/kg/day dosage groups. Teratogenicity was evident at visceral examination as a high incidence of cardiovascular defects, primarily defects of the ventricular septum, in fetuses from the 600 mg/kg/day dosage level group. The incidence of cardiovascular malformations among fetuses in the remaining dosage groups was comparable to or less than that of the concurrent control group. At skeletal examination treatment-related malformations were limited to an increased incidence of wavy rib in fetuses from the 150, 300, and 600 mg/kg/day dosage level groups. There were 14, 46, and 63 fetuses affected with this malformation in the 150, 300, and 600 mg/kg/day dosage level groups, respectively. This same malformations was also observed in 3 fetuses from the 75 mg/kg/day dosage level group, however, tis incidence is comparable to or less than the spontaneous frequency of this malformation observed in several individual historical control groups and was not considered to be an effect of drug administration. There were dose-related delays in fetal ossification, primarily of the skull bones, vertebra, and sternebra, in fetuses from all treatment groups. The number of fetuses with the delayed ossification was most apparent in the 150, 300 and 600 mg/kg/day dosage level groups and was considered to be primarily a reflection of the decrease in average fetal weight per litter previously mentionned at these dosage levels. The slight increase in sites of delayed ossification in the 75 mg/kg/day dosage level group compared to controls was not associated with a decrease in average fetal weight but was considered to be evidence of a fetotoxic effect. This slight delay in ossification is not a teratogenic effect since delays in ossifiction of this type are frequently observed in control fetuses, are transient, and result in no permanent skeletal alterations.

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

75 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

2

Dose descriptor:

NOAEL

Effect level:

75 mg/kg bw/day (nominal)

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:

Glycerol formal is foetotoxic and teratogenic in rats at dose of 150, 300 and 600 mg/kg/day. A 75 mg/kg/day was not teratogenic but was fetotoxic as evidenced by an increased incidence in sites of delayed ossification compared to the concurrent control group.

Executive summary:

An oral teratogenic study was performed in the rat in order to determine the threshold for the teratogenic effect of GF reported by Alivert et al. (1980). Female rats were treated with GF at 75, 150, 300 and 600 mg/kg/day from days 6 throught 17 of gestation.

No adverse effects were recorded on maternal body weight gain at any dose level.

There was a significant (P ≤ 0.05) increase in the numbers of dead and resorbed fetuses and a corresponding decrease in the number of live fetuses per litter in females from the 600 mg/kg/day dosage level group. No other adverse effects on reproductive status occured in any of the remaining dosage groups. There were dose-related statistically significant (P ≤ 0.05) decreases in average live fetal weight per litter in fetuses from dams administrated 150, 300 and 600 mg/kg/day of GF. There was no adverse effect on average live fetal weight inn fetuses from the 75 mg/kg/day dosage level group. There was a treatment-related incidence of anal atresia and tail malformations among fetuses from dams administrated 300 and 600 mg/kg/day of GF, and anasarca in fetuses from the 600 mg/kg/day group. There were no treatment-related external malformations in fetuses from the 78 and 150 mg/kg/day dosage groups. Teratogenicity was evident at visceral examination as a high incidence of cardiovascular defects, primarily defects of the ventricular septum, in fetuses from the 600 mg/kg/day dosage level group. The incidence of cardiovascular malformations among fetuses in the remaining dosage groups was comparable to or less than that of the concurrent control group. At skeletal examination treatment-related malformations were limited to an increased incidence of wavy rib in fetuses from the 150, 300, and 600 mg/kg/day dosage level groups. There were 14, 46, and 63 fetuses affected with this malformation in the 150, 300, and 600 mg/kg/day dosage level groups, respectively. This same malformations was also observed in 3 fetuses from the 75 mg/kg/day dosage level group, however, tis incidence is comparable to or less than the spontaneous frequency of this malformation observed in several individual historical control groups and was not considered to be an effect of drug administration. There were dose-related delays in fetal ossification, primarily of the skull bones, vertebra, and sternebra, in fetuses from all treatment groups. The number of fetuses with the delayed ossification was most apparent in the 150, 300 and 600 mg/kg/day dosage level groups and was considered to be primarily a reflection of the decrease in average fetal weight per litter previously mentionned at these dosage levels. The slight increase in sites of delayed ossification in the 75 mg/kg/day dosage level group compared to controls was not associated with a decrease in average fetal weight but was considered to be evidence of a fetotoxic effect. This slight delay in ossification is not a teratogenic effect since delays in ossifiction of this type are frequently observed in control fetuses, are transient, and result in no permanent skeletal alterations.

Glycerol formal is foetotoxic and teratogenic in rats at dose of 150, 300 and 600 mg/kg/day. A 75 mg/kg/day was not teratogenic but was fetotoxic as evidenced by an increased incidence in sites of delayed ossification compared to the concurrent control group.