Bis(2-ethylhexyl) carbonate

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:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions (groups of 10 instead of 20).

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

1997

Report date:

1997

Reference 2

Reference Type:

other company data

Title:

Unnamed

Year:

1991

Report date:

1991

Reference 3

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.31 (Prenatal Developmental Toxicity Study)

Version / remarks:

Cited as Directive 87/302/EEC, part B, p. 24

Deviations:

yes

Remarks:

10 animals per group instead of 20

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

10 animals per group instead of 20

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-ethylhexan-1-ol

EC Number:

203-234-3

EC Name:

2-ethylhexan-1-ol

Cas Number:

104-76-7

Molecular formula:

C8H18O

IUPAC Name:

2-ethylhexan-1-ol

Details on test material:

- Analytical purity: >/= 99.5%
- Purity test: gas chromatogaphy

Test animals

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Dr. K. Thomae GmbH, Biberach, Germany
- Age at study initiation: 68-85
- Weight at study initiation: 214-233
- Fasting period before study: no data
- Housing: singly, in stainless steel wire-mesh cages
- Diet: Kliba feed 343 ad libitum
- Water: ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Aqueous emulsions for gavage were freshly prepared every day under rapid stirring in doubly distileld water containing approx. 0.005% Cromophor EL

DIET PREPARATION
- Rate of preparation of diet (frequency): n.a
- Mixing appropriate amounts with (Type of food): n.a.
- Storage temperature of food: n.a.


VEHICLE
- Justification for use and choice of vehicle (if other than water): surfactant
- Concentration in vehicle:
- Amount of vehicle (if gavage): 0.005%
- Lot/batch no. (if required): no data
- Purity: no data

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Gas chromatography was used to verify test concentrations and stability during a 6-hr storage

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1:1 to 1:4
- Length of cohabitation: until successful
- 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:

gestation day 6 through 15

Frequency of treatment:

daily

Duration of test:

20 days

Doses / concentrations

Remarks:

Doses / Concentrations:
0 (water), 0 (vehicle), 130, 650, 1300 mg/kg day (in bidist. water containing 0.005% Cremophor EL)
Basis:
actual ingested

No. of animals per sex per dose:

10 females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: equimolar doses of 6 different alcohols including 2-EH were trested at 0, 1, 5, and 10 mmol/kg bw.
- Rationale for animal assignment (if not random): random
- Other:

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily



DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule:

BODY WEIGHT: Yes
- Time schedule for examinations: throughout the study


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): n.a., gavage study
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes / No / No data
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes / No / No data


WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): n.a., gavage study
- Time schedule for examinations:


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: uterus and ovaries, fetuses

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: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No data

Statistics:

Dunnett's test: food consumption, body weight data, uterus weight before opening, placental and fetal weights, number of corpora lutea, implantations, pre- and post implantationloses, resorptions, and live and dead fetuses.
Fisher's exact test: conception rate, mortality of the dams, all fetal findings

Indices:

No data published

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:

Maternal toxic effects:yes

Details on maternal toxic effects:
1300 mg/kg bw/day: significant toxicity (discoloration of liver and lung; pronounced clinical symptoms (nasal discharge, salivation, CNS depression); reduced food consumption, body weight loss; 6 mortalities.
650 mg/kg bw/day: slight maternal toxicity
130 mg/kg bw/day: no effect

Effect levels (maternal animals)

Dose descriptor:

NOAEL

Effect level:

130 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
1300 mg/kg bw/day: increased early resorptions, high postimplantation loss; fetal body weights markedly reduced; increased incidences of skeletal malformations, variations, and retardations.
650 mg/kg bw/day: slightly decreased fetal weight; increased number of fetuses with skeletal variations and retardations
130 mg/kg bw/day: no effect

Effect levels (fetuses)

1

Dose descriptor:

NOAEL

Effect level:

130 mg/kg bw/day

Basis for effect level:

other: embryotoxicity

2

Dose descriptor:

NOAEL

Effect level:

650 mg/kg bw/day

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

    
    

130 mg/kg dose group:
No adverse substance-related effects on dams or fetuses.

650 mg/kg dose group:
* maternal toxic effects
- 2 dams with piloerection
* embryo/fetotoxic effects
- slightly reduced mean fetal body weights
- increased frequency of fetuses with skeletal variations  
and retardations

1300 mg/kg dose group:
* maternal toxic effects
- markedly reduced food consumption during the whole  
treatment period (days 6-15 p.c.)
- distinctly reduced mean body weights (day 10 -20 p.c.)  
body weight loss during days 6-10 p.c. and reduced body  
body weight gains during days 10-15 p.c.; markedly reduced  
corrected body weight gain
- 6 animals found dead on days 9, 10 and 13 p.c.
- severe clinical sypmtoms like abdominal or lateral  
position, unsteady gait and apathy
- light brown-gray discoloration of the liver in the animals
  with intercurrent death; lund edema and emphysema in a   
few animals, and hemometra in 1 dam which showed vaginal  
hemorrage before death
- distinctly reduced mean uterus weight
* embryo/fetotoxic effects
- increased number of resorptions and consequently markedly 
  increased postimplantation loss
- markedly reduced mean fetal body weights
- one fetus with acaudia and atresia ani; increased  
incidence of fetuses with dilated renal pelvis and/or 
  hydroureter higher number of fetuses with skeletal 
  malformations, variations and retardations.




  
  





 

2 -EH: maternal and developmental toxicity (publication, table 5)


  

    

    
Dose levels (mg/kg bw/day)
  
  

    

    
0 (water)
    
0 (vehicle)
    
130
    
650
    
1300
  
  

    
No. pregnant dams
    
9
    
10
    
10
    
10
    
9
  
  

    
Fetuses and litters examined
    
124/9
    
146/10
    
130/10
    
127/9
    
28/2
  
  

    
Maternal deaths
    

    

    

    
1/10(a)
    
6/10
  
  

    
Pregnant at termination
    
9
    
10
    
10
    
10
    
9
  
  

    
Clinical signs
    

    

    

    
(+)
    
++
  
  

    
Body weight(g) day 0
    
231.5
    
230.8
    
229.6
    
225.5
    
235.6
  
  

    
Body weight (g) day 20
    
375.0
    
384.2
    
377.4
    
367.1
    
308.9**
  
  

    
Uterus weight (g)
    
77.7
    
82.2
    
72.2
    
75.9
    
32.9**
  
  

    
Corpora lutea /dam
    
16.1
    
16.0
    
15.4
    
15.7
    
15.3
  
  

    
Implantation sites/dam
    
15.0
    
15.7
    
13.6
    
14.8
    
14.8
  
  

    
Dams with viable fetuses
    
9
    
10
    
10
    
9
    
2
  
  

    
Postimplantation loss (%)
    
8.2
    
7.0
    
5.0
    
4.5
    
54.7**
  
  

    
Live fetuses/dam
    
13.8
    
14.6
    
13.0
    
14.1
    
14.0
  
  

    
Resorptions (total/early/dam)
    
1.2/1.1
    
1.1/1.0
    
0.6/0.5
    
0.7/0.2
    
7.8**/7.8**
  
  

    
Fetal weight (g)
    
3.80
    
3.82
    
3.80
    
3.44**
    
2.86**
  
  

    
No. (and %) of fetuses with malformations
    
1 (0.8)
    
2 (1.4)
    
3 (2.3)
    
7 (5.5) 
    
5** (17.9)
  
  

    
No. (and %) of litters with malformations (b)
    
1(11)
    
2(20)
    
3(30)
    
4(44)
    
2(100)
  
  

    
No. (and %) of fetuses with variations (b)
    
46 (37)
    
46 (32)
    
41(32)
    
49 (39)
    
20 (71)**
  
  

    
No. (and %) of litters with variations (b)
    
8(89)
    
10(100)
    
9(90)
    
8(89)
    
2(100)
  
  

    
No. (and %) of fetuses with retardations (b)
    
28(23)
    
38(26)
    
31(24)
    
51(40)
    
15(54)**
  
  

    
No. (and %) of litters with retardations (b)
    
8(89)
    
10(100)
    
8(80)
    
9(100)
    
2(100)
  




  (a) due to gavage error       (b) 
  percentage rounded



  **p0.01



  



   


2-EH: incidence (%) and type of fetal findings; selected data (publication, tabe 6)




  

    

    
Dose levels (mg/kg bw/day)
  
  

    

    
0 (water)
    
0 (vehicle)
    
130
    
650
    
1300
  
  

    
No. of fetuses and litters examined
    
124/9
    
146/10
    
130/10
    
127/9
    
28/2
  
  

    
Dilated renal pelvis
    
23 (6)
    
28 (9)
    
18 (8)
    
21 (7)
    
10 (2)
  
  

    
Hydroureter
    
1
    
3 (2)
    
2 (2)
    
1
    
3
  
  

    
Total skeletal variations
    
23 (7)
    
17 (6)
    
23 (8)
    
27 (7)
    
10 (2)
  
  

    
Total skeletal retardations
    
28 (8)
    
38 (10)
    
31 (8)
    
51 (9)
    
15 (2)
  


  






   






  

Applicant's summary and conclusion

Conclusions:

Clear signs of developmental toxicity, but not teratogenicity, were seen in the absence of maternal toxicity.

Executive summary:

The developmental toxicity of 2 -EH was investigated in a OECD TG 414 study conducted according to OECD TG 414 and under GLP, but using low rat numbers (10 instead of 20 pregnant females). This invalidates the study to some extend, but it provides weight of evidence for the developmental toxicity endpoint.

Maternal toxicity was most severe at the high dose level and marginal at the intermediate dose level. At the low dose no maternal toxicity was noted. Therefore the NOAEL is 130 mg/kg/d for this endpoint under the conditions of this study.

Signs of embryo-/fetotoxicity were dose-dependently noted in dams showing signs of maternal toxicity at 650 and 1300 mg/kg/d. Therefore the NOAEL is 130 mg/kg/d for this endpoint under the conditions of this study.

Teratogenicity was noted in fetuses from the high dose dams only. Therefore the NOAEL is 650 mg/kg/d under the conditions of this study for teratogenicity.