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Toxicological information

Developmental toxicity / teratogenicity

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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:
Comparable to guideline study with acceptable restrictions. Compares with guideline studies except low number of animals (groups of 10 instead of 20). Read-across justification: The substance is hydrolytically unstable. When it comes in contact with water or moisture complete hydrolysis will take place with no significant reaction products other than alcohol and hydrated titanium dioxide. This rapid hydrolysis (hydrolysis half-life < 3 minutes to < 2 hours) is the driving force for the toxicokinetics of target substance. Because of the rapid hydrolysis, the influence of the mode of administration through inhalation, dermal and oral is related to the hazardous degradation product (alcohol) released from the target substance. The identification of degradation products from the hydrolysis study conducted for the target substance verifies that there are no impurities in the alcohol released from the target substance, which might change the hazardous properties of the target substance compared to the properties of the pure alcohol. As there is a mechanistic reasoning to the read-across, the unnecessary animal testing is avoided by using the read-across data from the degradation product (relevant alcohol) to evaluate irritation, sensitization and the short term and long-term toxicological effects and mutagenicity of the target substance.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Unnamed
Year:
1997
Report Date:
1997
Reference Type:
other company data
Title:
Unnamed
Year:
1991
Report Date:
1991
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
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
Qualifier:
according to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
10 animals per group instead of 20
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Analytical purity: >/= 99.5%
- Purity test: gas chromatogaphy

Test animals

Species:
rat
Strain:
Wistar
Details on test animals 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)

open allclose all
Dose descriptor:
NOAEL
Effect level:
130 mg/kg bw/day
Basis for effect level:
other: embryotoxicity
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

Read-across justifications and data matrices are presented in IUCLID section 13.    
    
    
    

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:
The developmental toxicity of 2 -EH was investigated in a rat feed study for its potential for developmental toxicity. Pregnant female Wistar rats received 2-EH in the diet at concentrations of 0 (water), 0 (vehicle), 130, 650, 1300 mg/kg day gestation day 6 through 15. Following NOAELs were established: NOAEL maternal toxicity 130mg/kg/day, NOAEL toxicity to reproduction 130mg/kg/day, NOAEL teratogenicity 650mg/kg/day.
Executive summary:

The degradation product of Titanium tetrakis(2 -ethylhexanolate),2 -EH, was investigated in a OECD TG 414 study conducted 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. Clear signs of developmental toxicity, but not teratogenicity, were seen in the absence of maternal toxicity.

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.