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Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
1976
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
only 2 doses tested. Allthough not all details on the study design were provided, the study was performed to the highest standards at the time of conduct. In the current study, a concurrent test article, dioctyl calcium sulfosuccinate (DCS) was also tested at 0.5, 1, 1.5 and 2% in the diet.
Justification for type of information:
Data has been read across from a structurally similar substance in a category approach. See further discussion in the read across justification attached.
Cross-reference
Reason / purpose:
read-across: supporting information

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1976
Report Date:
1976

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Aerosol® OT-100, Sodium Dioctyl Sulfosuccinate
- Physical state: white, waxy solid
- Analytical purity: >97%

Test animals

Species:
rat
Strain:
Sprague-Dawley
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories
- Age at study initiation: about 2 months
- Housing: individually in hanging wire mesh cages
- Diet (e.g. ad libitum): Wayne Lab Meal ad libitum
- Water (e.g. ad libitum): ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 24±2°C
- Humidity (%): 50±5%
- Photoperiod (hrs dark / hrs light):12/12

Administration / exposure

Route of administration:
oral: feed
Vehicle:
corn oil
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: 40% solution in corn oil

DIET PREPARATION
- Mixing appropriate amounts with (Type of food): 1.0% and 2.0% admixed in Wayne Lab Meal

VEHICLE
- Concentration in vehicle: 40% solution in corn oil
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
Not provided
Duration of treatment / exposure:
gestational days 6 through 15: dosing
Duration of test:
gestational days 6 through 15: dosing
gestational day 21: killing of the mothers and removing fetuses by cesarean section
Doses / concentrations
Remarks:
Doses / Concentrations:
1.0 and 2.0%
Basis:
nominal in diet
No. of animals per sex per dose:
22 female rats in dose 1.0%
20 female rats in dose 2.0%
Control animals:
yes, concurrent vehicle

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes (clinical condition and signs of illness)
- Time schedule: each day

BODY WEIGHT: Yes (weight gain)
- Time schedule for examinations: day 6-15; day 15-21

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g
food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight
gain data: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day #21
- Organs examined: Ovaries and uterine content

Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Number of corpora lutea: No
- Number of implantations: Yes
- Number of resorptions: Yes

Fetal examinations:
- External examinations: Yes:
- Soft tissue examinations: No
- Skeletal examinations: Yes: [one half of the total number of fetuses]
- Head examinations: No
-Visceral examinations: Yes (one-half of the total number of fetuses were fixed in Bouin’s fluid for a detailed examination of visceral anomalies, using the slicing method of Wilson)

Statistics:
Maternal body-weight gains, maternal food consumptions and fetal weights were analyzed by Dunnett’s two-sided, multiple comparison test. Frequencies of resorptions and fetal abnormalities among litters were analyzed by the Mann-Whitney U test or the Chi-square test (with Yate’s correction), as appropriate.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
at 2% in the diet there were significant depression of bodyweight gains in the parental females
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
at 2% in the diet there were significant depression of bodyweight gains in the parental females
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
not specified
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
not examined
Histopathological findings: neoplastic:
not examined
Other effects:
no effects observed

Maternal developmental toxicity

Number of abortions:
effects observed, treatment-related
Description (incidence and severity):
In the 2.0% DSS group 1 pregnancy with total resorptions was observed (No statistical significance).
Pre- and post-implantation loss:
effects observed, treatment-related
Description (incidence and severity):
Among rats given dietary levels of 2.0% DSS, there were significant increases in the number of resorptions of 13.7% as compared to the control frequency of 5.6%
Total litter losses by resorption:
effects observed, treatment-related
Description (incidence and severity):
In the 2.0% DSS group 1 pregnancy with total resorptions was observed (No statistical significance). No pregnancy with total resorptions was observed in the control or 1.0% DSS group.
Early or late resorptions:
effects observed, treatment-related
Description (incidence and severity):
Among rats given dietary levels of 2.0% DSS, there were significant increases in the number of resorptions of 13.7% as compared to the control frequency of 5.6%.
Dead fetuses:
no effects observed
Changes in pregnancy duration:
not examined
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Effects on pregnancy duration" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsMaternalAnimals.MaternalDevelopmentalToxicity.EffectsOnPregnancyDuration): not examined
Other effects:
not examined
Details on maternal toxic effects:
Maternal toxic effects:yes. Remark: 2.0% Docusate sodium in the diet

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
1 074 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Basis for effect level:
body weight and weight gain
early or late resorptions
Remarks on result:
other: 1% in the diet

Results (fetuses)

Fetal body weight changes:
no effects observed
Description (incidence and severity):
Migrated Data from removed field(s)
Field "Fetal/pup body weight changes" (Path: ENDPOINT_STUDY_RECORD.DevelopmentalToxicityTeratogenicity.ResultsAndDiscussion.ResultsFetuses.FetalPupBodyWeightChanges): no effects observed
Reduction in number of live offspring:
not examined
Changes in sex ratio:
not specified
Changes in litter size and weights:
not examined
Changes in postnatal survival:
not examined
External malformations:
effects observed, treatment-related
Description (incidence and severity):
Near toxic or toxic dietary levels of 2.0% Ddocusate sodium produced significant incidences of gross abnormalities either among litters (25.0%) or fetal populations (20.2%) as compared to none in the controls. These abnormalities consisted of cranial buble, exencephaly, spina bifida (not significant), microphtalmia or anophtalmia (not significant).
Skeletal malformations:
no effects observed
Visceral malformations:
effects observed, treatment-related
Description (incidence and severity):
The visceral observations confirmed the significance of the exencephalous characteristics and anophtalmia for the group given dietary levels of 2.0% Docusate sodium.
Other effects:
effects observed, treatment-related
Description (incidence and severity):
In the 2.0% Docusate sodium group, skeletal observations revealed a significant incidence of variations including incomplete ossification to absence of the various cranial bones, a curved or open vertebral column, and a variety of defects of the vertebrae and ribs.
Details on embryotoxic / teratogenic effects:
Details on embryotoxic / teratogenic effects:
See Table 1.

Effect levels (fetuses)

open allclose all
Dose descriptor:
LOAEL
Effect level:
1 988 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Sex:
male/female
Basis for effect level:
external malformations
skeletal malformations
visceral malformations
Remarks on result:
other: 2% in the diet
Key result
Dose descriptor:
NOAEL
Effect level:
1 074 mg/kg bw/day
Based on:
act. ingr.
Sex:
male/female
Basis for effect level:
external malformations
skeletal malformations
visceral malformations
Remarks on result:
other: 1% in the diet

Fetal abnormalities

Key result
Abnormalities:
effects observed, treatment-related
Localisation:
external: cranium
skeletal: skull
skeletal: rib
visceral/soft tissue: central nervous system
visceral/soft tissue: eye
Description (incidence and severity):
only at 2.0% dietary level

Overall developmental toxicity

Key result
Developmental effects observed:
yes
Lowest effective dose / conc.:
2 other: %
Treatment related:
yes
Relation to maternal toxicity:
developmental effects as a secondary non-specific consequence of maternal toxicity effects
Dose response relationship:
yes
Relevant for humans:
no

Any other information on results incl. tables

Table 1. Maternal and fetal results of pregnant rats given various amounts if DSS in their diets during  gestational days 6 through 15.

Parameter

 Control        

1.0% DSS

2.0% DSS

Maternal

Group  (I-A)

(II-A)

(II-B)

No. of pregnant rats

43

22

20

No. of pregnancies with total resorptions

0

0

1

No. of pregnancies with viable fetuses

43

22

19

Average weight gain of dams with viable fetuses(g):

 

 

 

Days 6 to 15

78

86

52*

Days 15 to 21

66

67

77

Avarage, apparent food intake of dams with viable fetuses (g/rat/day):

 

 

 

Days 6 to 15

22.5

24.8

21.4

Days 15 to 21

28.6

32.1

33.4

Calculated compound consumed (mg/kg/day)

--

1074

1988

Litters

 

 

 

Total number of:

implantations

 

411

 

203

 

219

Resorptions

(% occurence)

23

(5.6)

8

(3.9)

30*a

(13.7)

Dead fetuses

(% occurrence)

3

(0.7)

0

1

(0.5)

Viable fetuses

(% occurrence)

385

(93.7)

195

(96.1)

188

(85.5)

Fetal weight (g)

4.6

5.2

4.7

Litters size (viable fetuses)

8.9

8.9

9.9

External major malformations1:

No. of litters affected

(% occurrence)

 

 

0

 

 

0

 

 

5*

(25.0)

No. of fetuses affected

(% occurrence)

 

0

 

0

36*a

(20.2)

* Significantly different from control (p< 0.05)

a Significance by Chi-square, but not Mann-Whitney U test

1 Primarily, exencephaly varying degrees and associated anomalies (See Table 2)

    

Table 2. Morphological observations of fetuses delivered from rats given DSS in their diets on gestational days 6 through 15.

Morphology

 Control

1.0% DSS

2.0% DSS

External observations1:

Group (I-A)

(II-A)

(II-B)

Total number examined

388a

195

189

Major anomalies:

  Adactyly

 

0

 

0

 

0

  Hemimelia

0

0

0

  Schistocelia

0

0

2

  Dome shaped head

0

0

0

  Cranial bubble (1-2mm)

0

0

9*

  Exencephaly

0

0

18*

  Exencephaly (cleft condition)

0

0

7*

  Anencephaly

0

0

0

  Spina bifida

0

0

6

  Macroglossia

0

0

0

  Micro- or anophtalmia

0

0

3

Defects:

  Hematoma (subcutaneous)

 

2

 

0

 

0

  Edamatous abdomen

0

0

0

  Tail short & curled

0

0

0

  Abducted fifth digit, left

   Rear foot

0

0

1

1 Fetuses may have more than one defect

a Fifty-four fetuses examined grossly only. (Shipment c valid as controls only)

      *Significantly different from control (p< 0.05) by Chi-square only

 

Table 3. Visceral observations of fetuses delivered from rats given DSS in their diets on gestation days  6 through 15.

Visceral observations

Dose:      Control

1.0 % DSS

2.0% DSS

Groups:       (I-A)

(II-A)

(II-B)

Total number of fetuses examined

165a

98

91

Defects1:

  Exencephalous   characteristics                     

 

0

 

0

 

11*

  Dilated lateral ventricles

1

3

5

  Microphtalmia

0

1

0

  Anolphtalmia

0

0

23*

  Retinal foldings

0

0

0

  Anotia or microtia

0

0

0

  Cleft palate

0

0

1

  Situs transversus – aorta, esophagus

  & stomach

1

0

0

  Intestinal agenesis

0

0

0

  Arch of aorta absent or right sided

0

0

0

  Diaphragmic hernia

0

0

1

  Dilated renal pelves

2

0

3

  Ectopic kidneys(s) &/or variation in size

1

0

0

  Renal agenesis

0

0

2

  Dilated ureters

6

0

3

  Adrenal agenesis

0

0

1

  Testes – ectopic or enlarged

1

0

1

  Hermaphroditism

0

0

3

1Fetuses may have more than one defect

aExcludes 1 fetus lost

*Significantly different from control (p<0.05) by Chi-square only

Table 4. Skeletal observations of fetuses delivered from rats given DSS in their diets on gestation days  6 through 15.

 

Skeletal observations

Dose:      Control

1.0 % DSS

2.0% DSS

Group  (I-A)

(II-A)

(II-B)

Total number of fetuses examined

167a

97

98

Defects1:

  Cranial bones,

  incomplete to lack of ossification :

   Nasal                    

 

 

 

0

 

 

 

0

 

 

 

4

   Frontal

1

0

20*

   Parietal

1

1

19*

   Interparietal

1

2

18*

   Supraoccipital

0

0

15*

   Exoccipital

0

0

2

   Atlas

0

0

1

   Zygomatic

0

0

1

   Premaxilla

0

0

1

   Tympanic bullae

0

0

5

   Mandibles

0

0

1

   Hyoid

0

0

3

  Eye orbit, reduction

0

0

0

  Exoccipital, fused to atlas

0

0

0

  Vertebrla column, curved &/or open

0

0

5

  Vertebrae:

 

 

 

   misshapened &/or retarded 

   development

0

0

5

   thoracic, bipartite centra

2

1

5

   lumbar, bipartite centra

0

0

2

  Sternebrae:

 

 

 

   fused

0

0

0

   hypoplastic to absent

0

0

1

   one or two absent

1

0

0

   staircase

0

0

3

   bipartite

0

0

2

  Rib(s):

 

 

 

   accesory

6

5

5

   Absent or less developed

0

0

7*

   wavy

2

2

0

   fused

0

0

2

  Pelvic, hypoplastic to absent

0

0

0

  Brachydactyly

0

0

0

  Syndactyly

0

0

0

  Adactyly

0

0

0

  Hemimelia & small scapula

0

0

 0

1Fetuses may have more than one defect

aExcludes 1 fetus destroyed during cleaning process

*Significantly different from control (p<0.05) by Chi-square only

 

Applicant's summary and conclusion

Conclusions:
Subtoxic dietary levels of 1.0% docusate sodium ingested on gestational days 6 through 15 showed no adverse effects on the various maternal or fetal parameters. Near toxic or toxic dietary levels of 2.0% DSS produced significant incidences of resorptions (13.7%) and gross abnormalities either among litters (25.0%) or fetal populations (20.2%) as compared to controls. Interpretation of the results of the present experiments, in which only maternally toxic dose levels induce teratogenicity, indicates no real hazard with the recommended human use of these surfactants.
Executive summary:

Prenatal developmental toxicity was studied in rats dosed from day 6 to day 15 of gestation by dietary administration of docusate sodium at dose levels of 1.0 and 2.0 % in the diet. Subtoxic dietary levels of 1.0% showed no adverse effects on the various maternal or fetal parameters. Near toxic or toxic dietary levels of 2.0% docusate sodium produced significant depressions in maternal weight-gains and increased incidences of resorptions (13.7%) and gross abnormalities either among litters (25.0%) or fetal populations (20.2%) as compared the controls. These abnormalities consisted primarily of exencephaly of varying degrees with, at times, spina bifida, anophtalmia and associated skeletal defects. The visceral observations confirmed the significance of the exencephalous characteristics and anophtalmia for the group given dietary levels of 2.0%. In this group, skeletal observations revealed a significant incidence of incomplete ossification to absence of the various cranial bones, a curved or open vertebral column, and a variety of defects of the vertebrae and ribs. There were significant depressions in maternal weight gains in the 2.0% Docusate sodium group . Interpretation of the results of the present experiment, in which only maternally toxic dose levels induce teratogenicity, indicates no real hazard with the recommended human use of these surfactants.

The concentration of 1% in the diet is considered as maternal and developmental NOAEL. This dose level corresponded with 1074 mg/kg body weight, as calculated in the study.