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

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Effect on fertility: via oral route

Endpoint conclusion:

no study available

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Effects on developmental toxicity

Description of key information

Glycerol formal produces no foetotoxic and teratogenic effects when orally administrated to pregnant rats at dose of 10 mg/kg/day.

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.

At more, adverse effects in animals testsis have been recorded in repeated dose toxicity tests.

Link to relevant study records

Reference

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

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

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

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

Remarks:

Doses / Concentrations:
75
Basis:
nominal conc.

Remarks:

Doses / Concentrations:
150
Basis:
nominal conc.

Remarks:

Doses / Concentrations:
300
Basis:
nominal conc.

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

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%)

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.

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

Abnormalities:

no effects observed

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.

Dose descriptor:

NOAEL

Effect level:

75 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: teratogenicity

Dose descriptor:

NOAEL

Effect level:

75 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

Abnormalities:

not specified

Developmental effects observed:

not specified

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.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

75 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Klimisch code 1

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

Justification for selection of Effect on developmental toxicity: via oral route:

Most complete study and of best quality, giving a clear NOAEL value

Justification for classification or non-classification

In the United Nations 2011 classification system, reproductive toxicity is subdivided under two main headings:

a)     Adverse effects on sexual function and fertility

Any effect of chemicals that would interfere with sexual function and fertility. This may include, but not be limited to, alterations to the male and female reproductive system, adverse effects on onset of puberty, gamete production and transport, reproductive cycle normality, sexual behaviour, fertility, parturition, pregnancy outcomes, premature reproductive senescence, or modifications in other functions that are dependent on the integrity of the reproductive systems.

In our opinion, Glycerol Formal warrants classification as a Category 2: Suspected human reproductive toxicant.

This opinion is based on the treatment related alterations seen in the male reproductive organs on the 3 month dog and rat studies and on the treatment related alterations in the ovaries of rats on the 3 month subcutaneous toxicity study. More weight was given to the alterations in the male reproductive system which occurred in 2 species, a rodent and a non-rodent.

Three month dog intramuscular toxicity study (UL/1326)

Changes were seen in the testes (retarded seminal epithelium or reduced spermiogenesis) and epididymes (degenerated cells from seminal epithelium in ductus epididymidis) of males receiving 0.24 ml/kg of a 30% or 50% solution and were considered not to be secondary to the change seen in the kidneys and thyroid because the male reproductive organs were affected in some animals which did not show changes in the other organs.

Three month rat oral toxicity study (UL/1324)

Treatment related changes were seen in the testes (slight inhibition of spermiogenesis to total atrophy) and epididymes and seminal vesicles. Severe changes such as complete atrophy in the testes were still apparent after 6 weeks recovery.

These changes were considered not to be secondary to the change seen in the spleen because the male reproductive organs were affected in some animals which did not show changes in the spleen.

Three month rat subcutaneous toxicity study (UL/1325)

Treatment related changes were seen in the testes (inhibition of spermiogenesis to total atrophy) and epididymes and seminal vesicles. Severe changes such as atrophy in majority of the tubuli contorti in the testes were still apparent after 6 weeks recovery.

Treatment related changes were also seen in the ovaries, only small to medium sized follicles present. This alteration was not apparent after 6 weeks recovery.

These changes were considered not to be secondary to the other changes seen in the study.

b)     Adverse effects on development of the offspring.

Developmental toxicity essentially means adverse effects induced during pregnancy, or as a result of parental exposure. These effects can be manifested at any point in the life span of the organism. The major manifestations of developmental toxicity include death of the developing organism, structural abnormality, altered growth and functional deficiency.

In our opinion, Glycerol Formal warrants classification as a Category 2: Suspected human reproductive toxicant.

This opinion is based on the results of the rat oral teratogenicity study  (TT ≠ 80-717-0) on which there was clear evidence of the full spectrum of teratogenicity and fetotoxicity (embryo-fetal death, structural abnormalities, retarded growth, delayed ossification of skeleton) in the absence of overt maternal toxicity.