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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Developmental toxicity of diethanolamine applied cutaneously to CD rats and New Zealand White rabbits,
Author:
Marty MS, et al.
Year:
1999
Bibliographic source:
Regul. Toxicol. Pharmacol., 30, 169-181
Report Date:
1999
Reference Type:
study report
Title:
Unnamed
Year:
1992

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Principles of method if other than guideline:
Prenatal developmental toxicity study with dermal application in rabbits
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals and environmental conditions:
- Source: Hazleton research Products Inc., Denver, PA
- Weight at study initiation: 2959-4414 g
- Housing: individual
- Diet Ground certified rodent diet (RMH 3200, Agway. Inc. Waverly, NY) ad libitum
- Water ad libitum
- Acclimation period: 2 weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16-21
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
dermal
Vehicle:
unchanged (no vehicle)
Details on exposure:
TEST SITE
- Area of exposure: no data (clipped back skin)
- % coverage: 100
- Type of wrap if used: steril gauze and further occluded with polyvenyl film attached to a specially designed Lycra-Spandex jacket  with Velcro closures
- Time intervals for shavings or clipplings: no data


REMOVAL OF TEST SUBSTANCE
- Washing (if done): warm water
- Time after start of exposure: 6 hours


TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 4 mL
- Constant volume or concentration used: yes

USE OF RESTRAINERS FOR PREVENTING INGESTION: no
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
gas chromatography
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 2/1
- Length of cohabitation: overnight
- Verification of same strain and source of both sexes: yes
- Proof of pregnancy: day of coitus referred to as day 0 of pregnancy
Duration of treatment / exposure:
gestation days 6 - 18
Frequency of treatment:
6 h/day
Duration of test:
gestation days 0-29
Doses / concentrationsopen allclose all
Dose / conc.:
35 mg/kg bw/day (nominal)
Dose / conc.:
100 mg/kg bw/day (nominal)
Dose / conc.:
350 mg/kg bw/day (nominal)
No. of animals per sex per dose:
15
Control animals:
other: water
Details on study design:
- Dose selection rationale: based on preliminary results of developmental toxicity range finding studies

In these studies, DEA concentrations of 500 mg/kg/day or greater produced excessive maternal toxicity, which included severe skin irritation (i. e., necrosis, eccbymosis, edema, and severe erythema), increased relative and absolute liver weights, and inkidney weights. Minor skin irritation and increased liver weights were observed for some rabbit dams exposed to 250 mg DEHA/day.

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily


DETAILED CLINICAL OBSERVATIONS: Yes (skin)
- Time schedule: twice daily during the dosing period, once daily during the post-treatment period


BODY WEIGHT: Yes
- Time schedule for examinations: GD 0, 6, 9, 12, 15, 24, 29


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Time schedule for examinations: daily

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 29
- Organs examined: liver, kidney


BLOOD:
- Prior to sacrifice on GD 29
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 (variation/malformation) / half per litter (thoracic, abdominal visceral abnormalities)
- Soft tissue examinations: No data
- Skeletal examinations: Yes: all per litter
- Head examinations: Yes: half per litter
Statistics:
Continuous variables were compared for homogeneity of variance using  Levene's test for equal variances (Levene, 1960). A parametric or nonparametric analysis of variance (ANOVA) was performed , f parametric ANOVA analyses were significant, pooled T-tests were used for pairwise comparisons. If results from a nonparametric ANOVA were significant, separate variance T tests for pairwise comparisons were performed. Data  from nongravid females and females delivering early were not included in the statistical analyses. Nonparametric data were statistically evaluated using the Kruskal-Wallis test, followed by the Mann Whitney U test. Incidence data were compared using the Fisher's exact test (Sokal and  Rohlf, 1969), with the exception of frequency data for fetal malformations and variations, statistical analyses were performed using BMDP Statistical Software (Dixon, 1990). For all statistical tests, the critical level of significance was set a priori at a = 0.05 (two-tailed).

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects: yes

Details on maternal toxic effects:
Maternal toxic effects:
- Body weight data: There was an overall decrease in gestational body weight gains in the 100 and 350 mg/kg bw dose groups during the treatment period. At the highest dose, weight gain was decreased during the post-treatment period.
- Food consumption: On GD 17 and 18 of the treatment period and for 4 days subsequent to treatment, food consumption was reduced in the 350 mg/kg bw group. 
- Clinical signs: Skin lesions and irritation were observed in the 350 mg/kg bw group during both the DEA treatment period and the subsequent recovery period. There were no perceptible changes in skin irritation or lesion frequency in rabbits administered 35 or 100 mg/kg/day. Skin irritation was not observed in the water control group.

Examination of dams at termination:
- Reproduction data of dams: There were no significant effects on reproductive parameters. One dam from the 350 mg/kg bw group aborted her litter on GD 27, an outcome which  followed a sharp decline in food consumption beginning on GD 14-15. At  necropsy, this animal had color changes in the kidneys and a reticular  pattern in all hepatic lobes. One dam from the 100 mg/kg/day group had a  single implantation site with a fetus that had undergone early resorption.
- Hematology: There were no significant changes in hematological parameters at any of  the DEA doses tested.
- Gross pathology and organ weights: At the high dose, 50% of treated rabbit dams exhibited color changes in the kidneys compared with 17% in control rabbits. Although not statistically significant, absolute and relative liver weights and  relative kidney weights were increased.

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
35 mg/kg bw/day
Basis for effect level:
other: maternal toxicity

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Details on embryotoxic / teratogenic effects:
No effect on the overall incidence of external, visceral, or skeletal malformations or variations observed in rabbit fetuses. Although there was a greater variety of malformations in the 350 mg/kg bw group, many of these malformations (ovoid lenses; common truncus; ventricular septal defect; herniated diaphragm; extra lumbar centrum No. 8; extra bilateral lumbar arch No. 8; bone island at caudal segment No. 2; and duplicated, misshaped, and fused sternebrae) occurred in the same fetus. Furthermore,  the overall incidence of malformations in the high dose DEA group (4.5%  of fetuses, 30.8% of litters) was similar to the incidence seen in control animals (6.7% of fetuses, 25.0% of litters). Of the 53 different fetal skeletal variations observed, only the occurrence of poorly ossified interparietal was statistically increased in the 350 mg/kg/day dose group. However, a consistent, dose-dependent profile of delayed ossification in the head region was not observed.

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEL
Effect level:
> 350 mg/kg bw/day
Basis for effect level:
other: teratogenicity

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Any other information on results incl. tables

Results summary:

DEA was administered to pregnant New Zealand White rabbits from gestation day 6 through day 18 at concentration of 0, 35, 100 and 350 mg/kg bw.

Rabbit dams at 350 mg/kg bw showed several signs of marked skin irritation, reduced food consumption, and color changes in the kidneys but no hematological changes. Body weight gain was reduced at 100 mg/kg bw.

There was no impairment of gestational parameters.

No evidence of developmental toxicity was observed at any dose level, especially, there were no apparent effects of treatment on the incidences of external, visceral, or skeletal abnormalities.

Consequently, the NOAEL for maternal toxicity was 35 mg/kg bw, the NOAEL for prenatal developmental toxicity including teratogenicity was >350 mg/kg bw.

Detailed results:

Maternal, litter, fetal data - prenatal developmental toxicity data

mg/kg bw        

0

35

100

350

femals used

15

15

15

15

pregnant

12

14

14

14

Mortality

0

0

0

0

BWG GD 6-18 (g)

59

98

12

-5.6

FC GD 6-18 (g)

164

175

160

152

Skin irritation        

0

0

0

10

Gravid uterus (g)

528

562

513

542

Corpora lutea 
(mean)                

9.6

9.8        

9.1        

9.5

Implantation 
(mean)                

8.0        

8.7        

8.0        

9.1

% Resorption

16.7        

7.1        

21.4        

23.1

Live fetuses 
(mean)                

7.5        

8.6        

7.7        

8.5

Fetal weight (g)

44

44

43

40

Total external malformations (fetus/litter)        

1/1

0/0

0/0

1/1

Total external variations (fetus/litter)        

0/0

0/0

0/0

0/0

Total soft tissue malformations (fetus/litter)        

4/1

9/4

5/3

2/2

Total soft tissue variations (fetus/litter)        

19/12        

30/9        

28/10

35/13

Total skeletal malformations (fetus/litter)        

1/1

1/1

2/2

3/3

Total skeletal variations (fetus/litter)        

90/12        

120/14        

108/13        

111/13

BWG = body weight gain, FC = food consumption, * p<0.05;  **p<0.01

Applicant's summary and conclusion