Ethylene diformate

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP-Guideline study, tested with the source substance Sodium formate (CAS No. 141-53-7). According to the ECHA guidance document “Practical guide 6: How to report read-across and categories (March 2010)”, the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sodium formate

EC Number:

205-488-0

EC Name:

Sodium formate

Cas Number:

141-53-7

IUPAC Name:

sodium formate

Details on test material:

- Name of test material (as cited in study report): Sodium formate
- Analytical purity: 100%

Test animals

Species:

rabbit

Strain:

Himalayan

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH (former Charles River Laboratories, Germany)
- Age at study initiation: 13-21 weeks
- Body weight: 2560 g

Administration / exposure

Route of administration:

oral: gavage

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
For the preparation of the solutions, an appropriate amount of the test substance was weighed in a graduated measuring flask depending
on the dose group, topped up with doubly distilled water and subsequently thoroughly mixed until it was completely dissolved.


VEHICLE
- Amount of vehicle: 10 mL/kg bw

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

HPLC with external calibration. Column Synergi 4µ Hydro-RP 80 A, 250 x 3 mm. Eluant: phsophate buffer pH 2.9. UV-detection at 200 nm (report, page 229 onwards).

Details on mating procedure:

- Impregnation procedure: artificial insemination, day of insemination designated Day 0 of the study

Duration of treatment / exposure:

Days 6-28 post implantation

Frequency of treatment:

daily, 7 days/week

Duration of test:

22 days

Doses / concentrations

Remarks:

Doses / Concentrations:
100, 300 and 1000 mg/kg body weight/day
Basis:
actual ingested

No. of animals per sex per dose:

25 females

Control animals:

yes, concurrent vehicle

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Clinical signs: checked each day
- Mortality: checked twice daily on working days, once on Saturday, Sunday, at public holidays

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: animals were observed daily or more often when clinical signs of toxicity were elicited.

BODY WEIGHT: Yes
- Time schedule for examinations: recorded regularly throughout the entire study period, i.e. on Days 0, 2, 4, 6, 9, 11, 14, 16, 19, 21, 23, 25, 28 and 29 p.i.

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes.
Food consumption was recorded daily throughout the entire study period.


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 29
- Organs examined: all females were sacrificed and assessed by gross pathology (including weight determinations of the unopened uterus and the placentae). For each doe, corpora lutea were counted and number and distribution of implantation sites (differentiated by resorptions, live and dead fetuses) were determined. Number and distribution of implantations sites were classified as live fetuses and dead implantations. Dead implantations comprised early resorptions, late resorptions and dead fetuses.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Placenta 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:

Simultaneous comparison of all dose groups with the control group using the DUNNETT-test (two-sided) for the hypothesis of equal means * for p < 0.05, ** for p < 0.01: Food consumption, body weight, body weight change, corrected, body weight gain (net maternal, body weight change), carcass, weight, weight of unopened, uterus, number of corpora lutea, number of implantations, number of resorptions, number of live fetuses, proportions of preimplantation loss, proportions of postimplantation loss, proportions of resorptions, proportion of live fetuses in each litter, litter mean fetal body weight, litter mean placental weight. 
Pairwise comparison of each dose group with the control group using FISHER'S EXACT test (one-sided) for the hypothesis of equal proportions * for p < 0.05, ** for p < 0.01: Female mortality, females pregnant at terminal sacrifice, number of litters with fetal findings.
Pairwise comparison of each dose group with the control group using the WILCOXON-test (onesided) for the hypothesis of equal medians * for p < 0.05, ** for p < 0.01: Proportions of fetuses with malformations, variations and/or unclassified observations in each litter.

Indices:

Conception rate, pre- and postimplantation loss

Historical control data:

Included in Part III of the report

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
No clinical signs of toxicity, no treatement-related mortalities. Food consumption, body weights and necropsy findings not affected.

Effect levels (maternal animals)

1

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Fetal weight, sex distribution, placenta weight not affected. Pre- and postimplantation loss were not affected. External, soft tissue and skeletal malformations were not affected by treatment.

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: embryotoxicity

2

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Basis for effect level:

other: teratogenicity

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Any other information on results incl. tables

Analysis of Test Substance
By various analyses, the stability of the test substance solutions over a period of 13 days at room temperature was
demonstrated, and the correctness of the prepared concentrations was shown.

EFFECTS
1 - Parental animals

Mortalities: none in any of the groups.
Clinical signs: none in any of the groups.
Food consumption: comparable across all groups, no relevant difference in treated groups compared to the control group.
Body weights: comparable across all groups, no difference in treated groups compared to the control group.
Corrected body weight gain: did not reveal statistically significant differences between the test substance-treated groups and the control group.
Uterus weight: no effect; the mean uterus weights were comparable between all groups.

Necropsy findings: no test-substance related effect noted.

Table1: Selected results for does in test groups 0 - 3,  i.e. at 0, 100, 300, or 1000 mg/kg bw per day
===========================================================
Parameter        Group 0     Group 1    Group 2     Group 3
-----------------------------------------------------------
Females mated/   
pregnant/       25/24/24   25/23/23    25/22/22   25/23/23
with viable 
fetuses

Food con-
sumtion (g)      100.5       97.8         94.5       94.6
day 0-29                    (97%)         (94%)      (94%)

Body weight      306.0      323.5        260.5      297.7 
gain (g)                    (106%)       (85%)      (97%)
day 0-29

Necropsy         - - No treatment-related findings  - -        
findings 
in dams 

Conception         96          92          88         92
rate (%)

Abortions           0           0           0          0

Corpora lutea    201/24     196/23        193/22    185/23
total/number 
of dams                

Implantations    176/24     185/23        156/22    161/23
total/number 
of dams
        
Resorptions       13/24     16/23          19/22     22/23
total/number 
of dams

total number      163        169            137       139
of fetuses                

total number       24         23             22        23
of litters                

pre-implantation 12.5(19.1) 6.7(11.9)   18.4(24.9) 13.3(16.1)
loss (+/- SD) %                

post-implantation 7.3(10.1) 7.9(9.3)  13.0(16.4) 13.9(16.2)
loss (+/- SD) %

fetuses/litter  6.8(2.25)  7.3(1.7)  6.2(2.5)  6.0(2.0)
(+/- SD)
live fetuses/   92.7(10.1)  92.1(9.3) 87.0(16.4) 86.1(16.2)
litter (+/- SD) %                

placenta weight   4.7        4.5          4.6          4.3
(mean) [g]                  (96%)        (98%)       (92%)

fetus weight     37.8        36.4        36.7        35.2
(mean) [g]                  (96%)        (97%)       (93%)
 
Fetal sex ratio 38.7:61.3  50.9:49.1   54.0:46.0   51.1:48.9        
[ratio m : f]
===========================================================
SD = Standard Deviation


2 - Fetuses
There were no test substance-related effects in any of the test groups at 100, 300, and 1000 mg/kg bw/day. 

Table 2: Selected results for fetuses in test groups 0 - 3,  i.e. from does at 0, 100, 300, or 1000 mg/kg bw per day:
===========================================================
Parameter        Group 0     Group 1    Group 2     Group 3
-----------------------------------------------------------
Total external malformations [%]
Fetuses           0.0         0.0        0.7         0.7
Litter            0.0         0.0        4.5         4.3 
Affect. fetuses   0.0         0.0        0.6         0.5
per litter

Total external variations [%]
Fetuses           4.3         0.6        2.2         1.4
Litter            13          4.3        9.1         8.7
Affect. fetuses   2.3         0.9        2.0         1.4
per litter

Skeletal malformations [%]
Fetuses           1.8         1.8        1.5         3.6
Litter            13          13         9.1         22 
Affect. fetuses   2.3         2.0        1.0         3.4
per litter

Skeletal variations [%]
Fetuses           52          65         60          65
Litter           100          91         95          96
Affect. fetuses   53.5        61.8       62.2        65.7
per litter

Soft tissue malformations [%]
Fetuses           1.2         0.6       2.2         4.3
Litter            8.3         4.3       14          26
Affect. fetuses   1.5         0.5       2.1         4.5
per litter

Soft tissue variations [%]
Fetuses           4.3         11        11          10
Litter            21          48        41          39
Affect. fetuses   4.2        10.9       9.4         8.9
per litter
===========================================================