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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Remarks:
The two substances share structural similarities with common functional groups, esters, and side chains varying in their length. Moreover, the side chains are chemically simple structures which are closely related to substances of known low toxicity.
Adequacy of study:
key study
Study period:
2004
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions; few details on test substance given, no analysis of the test compound

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2004

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
few details on test substance given, no analysis of the test compound
GLP compliance:
not specified
Limit test:
no

Test material

Constituent 1
Reference substance name:
Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate
EC Number:
234-392-1
EC Name:
Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate
Cas Number:
11138-60-6
IUPAC Name:
2,2-bis[(octanoyloxy)methyl]butyl decanoate
Constituent 2
Reference substance name:
Trimethylolpropane caprylate caprate
IUPAC Name:
Trimethylolpropane caprylate caprate
Test material form:
solid - liquid: suspension
Details on test material:
TMPCC (ExxonMobil, Lot No. 2, batch no. BL2027) was stored at room temperature.

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Kingston, NY
- Age at study initiation: young adult
- Weight at study initiation: Mean of the maternal body weight: 226 g (Vehicle), 225 g (200 mg/kg bw/day), 227 g (600 mg/kg bw/day), 226 g (2000 mg/kg bw/day)
- Fasting period before study: No
- Housing: Virgin females were cohabitated with singly-housed male rats, one male per female rat for a maximum of 5 days and returned to individual housing in stainless steel wire-bottomed cages after mating.
- Diet: Certified Rodent Diet No. 5002 (PMI Feeds Inc. St.Louis, MO), ad libitum
- Water: water passaged through a reverse osmosis membrane with chlorine added as a bacteriostat, ad libitum
- Acclimation period: yes, period not mentioned

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25
- Humidity (%): 30 - 70
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:
dermal
Vehicle:
corn oil
Details on exposure:
- Doses: 0, 200, 600, and 2,000 mg/kg/day.

- Dose formulation: 0 (vehicle only), 100, 300, and 1,000mg/mL

- Dosage volume: 2 mL/kg.

- Application of dose: The dosage amount was applied directly to the clipped area on the dorsum of the rat at approximately the same time each day and spread uniformly over the area with a glass rod. The skin application site was occluded during treatment with a gauze pad secured with Vetrapt or Micropores tape to prevent oral ingestion and to minimize loss of material from under the patch.
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
Treatment on Gestation Days (GD) 6 - 15
Frequency of treatment:
daily
Duration of test:
Termination of the study by CO2 inhalation on GD 20.
Doses / concentrationsopen allclose all
Remarks:
Doses / Concentrations:
200
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
600
Basis:
nominal conc.
Remarks:
Doses / Concentrations:
2000
Basis:
nominal conc.
No. of animals per sex per dose:
25 females per group
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: Dose dependent occurrence of skin irritation. Higher levels than 2000 mg/kg bw/day might be expected to produce marked irritation thereby compromising the interpretaion of developmental results.
- Rationale for animal assignment (if not random): Computer-generated randomization by weight (Barlett´s test for homogeneity) such that the groups were not statistically different (5% significance level) from each other.

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS
- Time schedule: Animals were checked for mortality twice daily during the treatment period and daily thereafter.


DETAILED CLINICAL OBSERVATIONS
- Time schedule: Animals were checked for signs of reaction to treatment and/or symptoms of illness once daily before treatment, approx. 60 min after treatment during the dosing period. The dosing site was examined daily prior to substance application for signs of skin irritation according to Draize.


BODY WEIGHT
- Time schedule for examinations: Recorded on GD 0 and daily during the treatment period.


FOOD CONSUMPTION AND COMPOUND INTAKE
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg b.w./day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No


POST-MORTEM EXAMINATIONS
- Sacrifice on gestation day # 20
- Organs examined: The uterus, uterine contents, position of the fetuses in the uterus and number of corpora lutea. Number and distribution of intrauterine implantations were classified as live or death fetuses, late intrauterine deaths (resorptions) and early intrauterine resorption sites. Live fetuses were sexed and further examined (see below).

Ovaries and uterine content:
- Gravid uterus weight
- Number of corpora lutea
- Number of implantations
- Number of early resorptions
- Number of late resorptions
Fetal examinations:
- External examinations: all per litter
- Soft tissue examinations: half per litter
- Skeletal examinations: half per litter
- Head examinations: half per litter (the heads of the animals used for soft tissue examinations)
Statistics:
Clinical observation and other proportion data were analyzed using the Variance Test for Homogeneity of the Binomial Distribution (Snedecor and Cochran, 1967). Quantitative continuous data (e.g., maternal body weights, body weight changes, feed consumption values, litter averages for percent male fetuses, percent resorbed conceptuses, fetal body weights, fetal anomaly data, and fetal ossification data) were analyzed using Bartlett’s Test
for Homogeneity of Variance (Sokal and Rohlf, 1969) and the Analysis of Variance (Snedecor and Cochran, 1967) when Bartlett’s Test was not significant (p40.05). If the Analysis of Variance was significant (pr0.05), Dunnett’s Test (Dunnett, 1955) was used to identify the statistical significance of the individual groups. If the Analysis of Variance was not appropriate, i.e., Bartlett’s Test was significant (pr0.05), the Kruskal-Wallis Test (Sokal and Rohlf, 1969) was used when < 75% ties were present. In cases where the Kruskal-Wallis Test was statistically significant (p<0.05), Dunn’s Method of Multiple Comparisons (Dunn, 1964) was used to identify the statistical significance of the individual groups. If there were 475% tied, Fisher’s Exact Test (Siegel, 1956) was used to analyze the data. Count data obtained at Caesarian-sectioning of the dams were evaluated using the procedures described above for the Kruskal-Wallis Test.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
no effects observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Water consumption and compound intake (if drinking water study):
no effects observed

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes. Remark: local irritation

Details on maternal toxic effects:
The two highest dose levels caused some local irritation at the site of application, but no decreases in maternal weight gain or feed consumption. Two animals in the control group and one animal in the high-dose group died within 6 h after first application; these were not considered to be treatment related and the animals were replaced. One dam of the mid-dose goup (1/25) having a litter consisting of seven early resorptions was pointed out as single non-dosage dependent event and to be within the ranges observed historically at the test facility.
Necropsy findings were limited to skin flaking and scabbing first identified in life and observations related to wearing the Elizabethan collar (local alopecia, chromorhinorrhea, and neck lesions).

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEL
Effect level:
> 2 000 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: developmental toxicity
Dose descriptor:
NOAEL
Remarks:
local
Effect level:
200 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOAEL
Remarks:
systemic
Effect level:
2 000 mg/kg bw/day (nominal)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:

There were no significant differences from control in any of the developmental parameters measured, including embryo/fetal viability, fetal weight, malformations, or variations. The observed effects in fetuses were dose-independent and regarded to be sporadic.

Effect levels (fetuses)

Dose descriptor:
NOAEL
Effect level:
> 2 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
not specified
Basis for effect level:
fetal/pup body weight changes
changes in litter size and weights
external malformations
Remarks on result:
not determinable due to absence of adverse toxic effects

Fetal abnormalities

Abnormalities:
no effects observed

Overall developmental toxicity

Developmental effects observed:
no

Any other information on results incl. tables

Table 1: Skin reaction observations

 

0 mg/kg bw/d

200 mg/kg bw/d

600 mg/kg bw/d

2000 mg/kg bw/d

Maximum possible incidencesa

375/25

375/25

375/25

375/25

Erythema

Total

0/0

2/1

22/4

91/13b

Grade 1

0/0

2/1

10/4

81/13b

Grade 2

0/0

0/0

4/1

10/4b

Flaking

Total

11/3

15/2

55/6

170/17b

Grade 1

11/3

9/2

27/5

61/14b

Grade 2

0/0

6/1

19/4

71/14b

Grade 3

0/0

0/0

9/1

38/7 b

Edema

Total

0/0

0/0

23/4

83/11b

Grade 1

0/0

0/0

18/4

59/11b

Grade 2

0/0

0/0

5/1

24/6b

Scab

0/0

0/0

6/2

19/4

a:       Maximum incidence : Days x rats from first treatment on GD 6 through sacrifice on GD 20 divided by the number of rats examined per group on GD 6-20

b:        Significantly different from vehicle control group value (p≤0.01)

 

Table 2: Maternal reproductive, litter, and fetal alteration observations: Caesarian-Section results on GD 20

 

0 mg/kg bw/d

200 mg/kg bw/d

600 mg/kg bw/d

2000 mg/kg bw/d

Rats pregnant and sectioned on Day 20 of gestation (n)

25

23

22b

24

Corpora lutea/dam

16.4

16.6

16.9

16.5

Implantation sites/litter

15.0

15.4

14.9

14.2

Litter size

Live fetuses/litter

14.6

14.6

14.0

13.3

Live fetuses (n)

364

335

308

320

Dead fetuses (n)

0

0

0

0

Resorptions

0.4

0.9

0.9

0.9

Early (n)

10

20

19

21

Late (n)

1

0

0

0

Dams with any resorptions n(%)

9 (36)

11 (48)

15 (68)

11 (46)

% resorbed/litter

2.9

5.4

5.8

5.0

% male/litter

51.3

50.8

48.1

47.7

Live fetal body weight (g/litter)

3.68

3.62

3.69

3.75

Male

3.77

3.68

3.82

3.85

Female

3.58

3.56

3.58

3.65

Fetuses evaluated (n)

364

335

308

320

Litters with any alterations observed n(%)

10 (40)

8 (35)

14 (64)

7 (25)

Fetuses with any alterations observed n(%)

13 (3.5)

10 (3.0)

20 (6.5)

9 (2.0)

% fetuses/litter with any alterations observed

3.5

2.9

6.8c

2.7

b:       Excludes values for one dam, which had a litter consisting of seven early resorptions.

c:       Significantly different from vehicle control group value (p≤0.05)

Table 3: Fetal evaluations

 

0 mg/kg bw/d

200 mg/kg bw/d

600 mg/kg bw/d

2000 mg/kg bw/d

Litters evaluated

25

23

22b

24

Fetuses evaluated

364

335

308

320

Live

364

335

308

320

Fetal gross external alterations

364

335

308

320

Tail: kinked

Litter incidence, n (%)

0(0)

1 (4.3)

0(0)

0(0)

Fetal incidence, n (%)

0(0)

1(0.3)

0(0)

0(0)

Body: hematoma

Litter incidence, n (%)

1(4.0)

0(0)

0(0)

0(0)

Fetal incidence, n (%)

1 (0.3)

0(0)

0(0)

0(0)

Fetal soft tissue alterations, evaluations

174

162

149

155

Vessels: umbilical artery descended to the left of urinary bladder

Litter incidence, n (%)

2(8.0)

3(13.0)

2(9.1)

2(8.3)

Fetal incidence, n (%)

2(1.1)

3(1.8)

3(2.0)

2(1.3)

Vessels: apparent additional umbilical artery descended left of the bladder

Litter incidence, n (%)

0(0)

0(0)

1(4.5)

0(0)

Fetal incidence, n (%)

0(0)

0(0)

1(0.7)

0(0)

Fetal skeletal alterations, evaluations

190

173

159

165

Cervical vertebrae: cervical rib present at 7th cervical vertebrae

Litter incidence, n (%)

2(8.0)

1(4.3)

1(4.8)

0(0)

Fetal incidence, n (%)

2(1.0)

2(1.2)

1(1.2)

0(0)

Thoracic vertebrae: centrum, bifid

Litter incidence, n (%)

1(4.0)

1(4.3)

5(22.7)

0(0)

Fetal incidence, n (%)

1(0.5)

1(0.6)

5(3.1)a

0(0)

Lumbar vertebrae: centrum, bifid

Litter incidence, n (%)

0(0)

1(4.3)

0(0)

0(0)

Fetal incidence, n (%)

0(0)

1(0.6)

0(0)

0(0)

Ribs: wavy

Litter incidence, n (%)

0(0)

0(0)

2(9.1)

1(4.2)

Fetal incidence, n (%)

0(0)

0(0)

2(1.2)

1(0.5

Sternal centra: 1st, not ossified

Litter incidence, n (%)

1(4.0)

0(0)

0(0)

2(8.3)

Fetal incidence, n (%)

1(0.5)

0(0)

0(0)

2(1.3)

Sternal centra: 1st, incompletely ossified

Litter incidence, n (%)

3(12.0)

3(13.0)

2(5.1)

1(4.2)

Fetal incidence, n (%)

4(2.1)

4(2.3)

2(1.2)

1(0.6)

Pelvis: pubis, incompletely ossified

Litter incidence, n (%)

3(12.0)

0(0)

4(18.2)

3(12.5)

Fetal incidence, n (%)

3(1.6)

0(0)

5(3.1)

3(1.8)

Pelvis: ischium, incompletely ossified

Litter incidence, n (%)

0(0)

0(0)

2(9.1)

0(0)

Fetal incidence, n (%)

0(0)

0(0)

2(1.2)

0(0)

a: Significantly different from vehicle control group (p≤0.01)

Applicant's summary and conclusion

Conclusions:
TMPCC did not cause any developmental toxicity in the Sprague-Dawley rat at dermal dosages up to 2,000 mg/kg/day.
Executive summary:

The developmental toxicity potential of trimethylolpropane caprylate caprate (TMPCC, CAS no. 11138-60-6) was evaluated in rats. Sprague-Dawley rats were administered TMPCC in a corn oil suspension dermally at dose levels of 0, 200, 600, or 2,000 mg/kg/day on gestation days (GD) 6–15 (sperm positive day5GD 0). Caesarean sections were performed on GD 20 and fetuses were evaluated for viability, growth, and external, visceral, and skeletal abnormalities. Each group consisted of 25 females, with at least 22 per group being pregnant. The two highest dose levels caused some local irritation at the site of application, but no decreases in maternal weight gain. There were no differences from control in any of the developmental parameters measured, including embryo/fetal viability, fetal weight, malformations, or variations. TMPCC did not cause any developmental toxicity in the Sprague-Dawley rat at dermal dosages up to 2,000 mg/kg/day.