Reaction products of ethylene glycol, urea and paraformaldehyde (EUF)

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

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

Additional information

No reproductive toxicity study with EUF has been performed. The substance gave no indication for adverse effects on the reproductive organs in the subchronic gavage studies in rats. Data on formaldehyde suggested that this hydrolysis product does not reach the reproductive organs and there is no evidence for effects on fertility in experimental animals after oral or inhalation exposure. In oral fertility studies, ethylene glycol did not influence fertility parameters in rats and mice, but in male mice effects on reproductive organs were noted with a NOAEL below 897 mg/kg bw/day. No effects, however, can be expected at the more relevant dermal or inhalation routes of exposure.

No evidence for an impairment of fertility parameters was noted for urea.

Short description of key information:

A two-generation reproduction study with EUF has not been performed. Instead, a waiver was submitted.

Effects on developmental toxicity

Description of key information

Oral administration of EUF in a prenatal developmental toxicity study influenced fetal development at a moderate to severe maternal toxic dose. No teratogenic effect was observed.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

January 29, 2008 to September 13, 2008 (experimental period)

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Japanese MAFF, 12 Nohsan No. 8147, Teratology (2-1-18) (November 2000)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rabbit

Strain:

Himalayan

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River, Germany
- Age at study initiation: 31 to 45 weeks
- Weight at study initiation: 2.282 to 3.498 kg at study start
- Fasting period before study: no
- Housing: Individually in stainless steel cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 7 days under test conditions with health check

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18+-3
- Humidity (%): 30-70
- Air changes (per hr): 10-15
- Photoperiod (12 hrs dark / 12 hrs light):

IN-LIFE DATES: From 22 January 2008 to 13 March 2008:

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Prepared daily as supplied by Sponsor and diluted with Milli-Q-Water

VEHICLE
- Justification for use and choice of vehicle (if other than water): Milli-Q-Water (highly purified water) was used to avoid interference with the analytical controls of dosing solutions
- Concentration in vehicle: 13.75, 27.5 and 55%
- Amount of vehicle (if gavage): 4 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

On the first day and last week of treatment, samples from control and all 3 dose levels were taken for analysis of concentration and homogeneity and analysed by GC.

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused: in individual cages
- M/F ratio per cage: 1/1
- Length of cohabitation: until successful copulation was observed
- Further matings after two unsuccessful attempts: not applicable, only proven males from supplier were used
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: day of mating referred to as day 0 of pregnancy

Duration of treatment / exposure:

Treatment was performed from Day 6 to 27 post coitum

Frequency of treatment:

Once daily

Duration of test:

28 days

Dose / conc.:

0 mg/kg bw/day

Dose / conc.:

55 mg/kg bw/day

Dose / conc.:

110 mg/kg bw/day

Dose / conc.:

220 mg/kg bw/day

No. of animals per sex per dose:

20 mated females per group

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose levels were selected after a preliminary dose range finding with dose levels of 60, 120 and 240 mg/kg bw/day, resulting in a NOAEL of 120 mg/kg bw/day

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: once daily

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: Recorded daily from day 0 until day 28 post coitum
Summarised for the following periods: days 0-3, 3-6, 6-9, 9-12, 12-15, 15-18, 18-21, 21-24 and 24-28 post coitum

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 28
- Organs examined: all internal organs with emphasis on uterus and contents

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:

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

Statistics:

Dunnet test (if variables followed a normal distribution)
Steel test (if variables did not follow a normal distribution)
Fisher's exact test (for macroscopic data evaluation)

Indices:

Pre-implanatation loss
Post-implantation loss

Historical control data:

Yes

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

At 220 mg/kg/day females which died or must be killed for ethical reasons showed a genital region smeared with urine and/or feces, ventral recumbence or reduced activity and ruffled fur.

Mortality:

mortality observed, treatment-related

Description (incidence):

At 220 mg/kg/day, five females were found dead or killed for ethical reasons.
No effects on mortality on other groups.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Maternal toxicity was present from 110 mg/kg bw (group 3) onwards. Beginning at this dose level, mean body weight gains were transiently reduced after the beginning of treatment

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Maternal toxicity was present from 110 mg/kg bw (group 3) onwards. Beginning at this dose level, mean food consumption were transiently reduced after the beginning of treatment

Description (incidence and severity):

110 mg/kg bw/day group: During necropsy for one female a red area in the pylorus region in the stomach was noted (most likely as sign of formaldehyde-induced local irritation).
220 mg/kg bw/day group: During necropsy, several females showed a stomach with crateriform areas, ulcerations or reddish discolorations

Pre- and post-implantation loss:

effects observed, treatment-related

Description (incidence and severity):

The mean post-implantation loss was statistically significantly increased, resulting in a statistically significantly reduced number of fetuses in the high dose group only (220 mg/kg bw/day)

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
Maternal toxicity was present from 110 mg/kg bw (group 3) onwards. Beginning at this dose level, mean food consumption and mean body weight gains were transiently reduced after the beginning of treatment. During necropsy for one female a red area in the pylorus region in the stomach was noted (most likely as sign of formaldehyde-induced local irritation).

At 220 mg/kg/day, five females were found dead or killed for ethical reasons. They showed a genital region smeared with urine and/or feces, ventral recumbence or reduced activity and ruffled fur. Mean food consumption and mean body weights were reduced during the treatment period. The mean post-implantation loss was statistically significantly increased, resulting in a statistically significantly reduced number of fetuses. During necropsy, several females showed a stomach with crateriform areas, ulcerations or reddish discolorations

Dose descriptor:

NOAEL

Effect level:

>= 55 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

Fetal body weight changes:

effects observed, treatment-related

Description (incidence and severity):

At the high dose (220 mg/kg bw), fetal parameters indicated that mean fetal body weights were statistically significantly reduced.

Skeletal malformations:

effects observed, treatment-related

Description (incidence and severity):

A statistically significantly higher incidence of supernumerary ribs was noted in the high dose group (220 mg/kg bw/day).

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
At the high dose (220 mg/kg bw), fetal parameters indicated that mean fetal body weights were statistically significantly reduced. Furthermore, a statistically significantly higher incidence of supernumerary ribs was noted. Post-implantation loss was increased.

Dose descriptor:

NOAEL

Effect level:

>= 110 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: fetotoxicity

Abnormalities:

not specified

Developmental effects observed:

not specified

Tables for maternal and fetal effects see under attached documents

Conclusions:

EUF (TPI 1618) administered orally during the major phase of organogenesis to pregnant Himalayan rabbits resulted in no indication for teratogenicity, but influenced fetal development at a moderate to severe maternal toxic dose. The NO(A)EL for maternal toxicity was 55 mg/kg bw and the NO(A)EL for fetal development was 110 mg/kg bw/day.

Executive summary:

The present study was designed to evaluate the potential of EUF (TPI 1618) to produce maternal and developmental toxicty (including teratogenicity) when administered by oral gavage during major organogenesis and fetal development in the Himalayan rabbit. The investigation was compliant with OECD 414 (2001), US-EPA OPPTS 870.3700 (1998) and Japanese MAFF (2000).
Dose levels of 55 (group 2), 110 (group 3) and 220 (group 4) mg/kg bw were given once daily from Day 6 to 27 p.c. to 20 mated rabbits per group.

The NO(A)EL for maternal toxicity was 55 mg/kg bw and the NO(A)EL for fetal development was 110 mg/kg bw/day.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

110 mg/kg bw/day

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

Developmental toxicity of EUF or formaldehyde is only expected secondary to local maternal effects.

EUF administered orally during the major phase of organogenesis to pregnant Himalayan rabbits resulted in no indication for teratogenicity, but influenced fetal development at a moderate to severe maternal toxic dose. Mean fetal body weights were statistically significantly reduced. Furthermore, a statistically significantly higher incidence of supernumerary ribs was noted. The increased incidence of supernumerary ribs in the fetuses might be secondary to the occurrence of maternal toxicity and are considered as variations of development. Rudimentary ribs are known to likely disappear during further development. The NO(A)EL for maternal toxicity was 55 mg/kg bw and the NO(A)EL for fetal development was 110 mg/kg bw/day.

The implementation of a developmental toxicity study in a 2^ndspecies is scientifically unjustified because no teratogenic effects are expected due to concentration-dependent local effects.

After hydrolysis, irritant/corrosive effects of formaldehyde are expected; local maternal effects but no developmental effects have been reported in inhalation studies. In oral studies no developmental toxicity occurred at dose levels inducing local maternal toxicity. Data on ethylene glycol indicated skeletal malformation at oral dose levels of 500 mg/kg and above, however, ethylene glycol is no hydrolysis product of concern as shown in the 90-Day oral toxicity study. Likewise no relevant contribution to the developmental toxicity for urea is expected.