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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:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles, acceptable for assessment.

Data source

Referenceopen allclose all

Reference Type:
publication
Title:
Assessment of the teratogenic potential of surfactants. Part II - AOS
Author:
Palmer, A.K. et al.
Year:
1975
Bibliographic source:
Toxicology 3: 107-113
Reference Type:
publication
Title:
Assessment of the teratogenic potential of surfactants. Part I - LAS, AS and CLD.
Author:
Palmer, A.K. et al.
Year:
1975
Bibliographic source:
Toxicology 3: 91-106

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
choice of dose range different from recommendations
GLP compliance:
no
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): AOS: mixture of alkenyl sulphonate and hydroxy-alkane sulphonate (60.4:39.6 % w/w)
- Analytical purity: not specified
- Composition of test material, percentage of components: 60.4 % alkenyl sulphonate, 39.6 % hydroxy-alkane sulphonate
- Other: Source: Lion Fat and Oil Co. Ltd., Tokyo, Japan

Test animals

Species:
mouse
Strain:
CD-1
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, Mass., USA, or St-Aubin-les-Elbeuf
- Housing: 5/cage
- Diet (e.g. ad libitum): Spratt's Laboratory Diet No. 1, ad libitum
- Water (e.g. ad libitum): ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 1
- Humidity (%): 50 ± 5

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
Prepared daily as a series of graded aqueous solutions to ensure oral dosing by intragastric intubation at a standard volume. Control animals were dosed with water.
Analytical verification of doses or concentrations:
not specified
Details on mating procedure:
- Impregnation procedure: cohoused
- If cohoused:
- Proof of pregnancy: vaginal plug referred to as day 0 of pregnancy
Duration of treatment / exposure:
GD6-15
Frequency of treatment:
daily
Duration of test:
GD17
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 0.2, 2, 300, 600 mg/kg/day
Basis:
nominal conc.
No. of animals per sex per dose:
20 mated females
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: The two lower dosages represent between 1-2 and 10-20 times the estimated human exposure level. The two higher dosages were also included with the intention of inducing obvious adverse effects, the pattern of which would help in assessing the relevance of any marginal differences occurring at lower dosages.

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations included: mortality, activity, appearance


DETAILED CLINICAL OBSERVATIONS: No


BODY WEIGHT: Yes
- Time schedule for examinations: regularly throughout gestation, not further specified


POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: uteri, ovaries
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 early resorptions: Yes
- Number of late resorptions: Yes
- Other: viable fetuses
Fetal examinations:
- External examinations: Yes: all per litter (viable young)
- Soft tissue examinations: Yes: 1/3 per litter
- Skeletal examinations: Yes: 2/3 per litter
- Head examinations: No
Statistics:
Calculation of group mean values: Mean A includes all surviving animals showing evidence of implantation, including those with total litter loss; Mean B includes only animals bearing viable young at termination. Mean B has more meaning when only occasionally an animal shows total litter loss, Mean A provides a better index when several animals show total litter loss.

Differences in mean values were statistically analysed by non-parametric methods (Wilcoxon test) since litter values rarely, if ever, follow a normal (Gaussian) distribution; in all analyses the litter was considered as the basic sample unit.
Historical control data:
The reproductive performance and rates of spontaneous malformation and anomaly of the animal strain used have been monitored over several years. Incidences of spontaneous malformations in the CD-1 mouse strain were reported from 22389 fetuses examined. Major malformations of 0.84 %, minor visceral anomalies of 3.68 % and minor skeletal anomalies of 5.32 % were reported.

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
At 600 mg/kg 6/20 mice died, the survivors showed reduced activity, pilo-erection and retarded weight gain, 5/20 showed total litter loss. At 300 mg/kg no mortality occurred, the animals showed pilo-erection, reduced activity and retarded weight gain, 6/20 showed total litter loss. At the lower dosages initial retardation of weight gain was observed

Effect levels (maternal animals)

Dose descriptor:
NOAEL
Effect level:
2 mg/kg bw/day (nominal)
Basis for effect level:
other: maternal toxicity

Results (fetuses)

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

Details on embryotoxic / teratogenic effects:
A high incidence of total litter loss occurred at 300 and 600 mg/kg resulting in high embryonic loss and, therefore, low litter size at both dosages. However, embryonic loss was considered to be unaffected in litters with viable young. The significantly higher number (but not proportion) of embryonic deaths at 300 mg/kg was correlated with a higher implantation rate. The pattern of response at 300 and 600 mg/kg suggests that the effects on litters were a consequence of a primary toxic action on the dam.

Litter and mean pup weights were lower than the concurrent controls at all dosages, occurring significant differences were a consequence of the unusually high concurrent control value for mean pup weight. The more marked reduction in litter and mean pup weight observed at the maternally toxic dosage of 600 mg/kg, was, therefore, considered the only difference from controls likely to be associated with treatment.

Cleft palate was observed in 4 pups (from 3 litters) at 600 mg/kg and in 2 pups (from 1 litter) at 300 mg/kg. At 600 mg/kg there was also a significantly high incidence of skeletal anomalies (mainly in the form of generally retarded ossification). A higher incidence of skeletal anomalies (retarded ossification of occipitalis) was also recorded with other dosages.

Effect levels (fetuses)

open allclose all
Dose descriptor:
NOAEL
Effect level:
2 mg/kg bw/day (nominal)
Basis for effect level:
other: embryotoxicity
Dose descriptor:
NOAEL
Effect level:
>= 600 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

Maternal effects:

 

Dosage (mg/kg bw/day)

Observation

0

0.2

2

300

600

Mated

20

20

20

20

20

Died

0

0

0

0

6

Non-pregnant

3

5

1

1

3

Total litter loss

2

1

1

6

5

Premature birth*

2

2

0

2

0

With viable young

13

12

18

11

6

Bodyweight change

-

Retarded gain

Retarded gain

Retarded gain

Retarded gain

*Excluded from calculation of mean values.

 

Mean litter data:

Dosage (mg/kg)

Number of litters

Litter size viable young

Embryonic deaths

Implantations

Embr. Loss % Post-Implant.

Litter weight (g)

Foetal weight (g)

0

A=15

9.9

2.5

12.5

20.6

-

-

 

B=13

11.5

1.0

12.5

8.4

14.03

1.23

0.2

A=13

9.9

2.8

12.7

20.9

-

-

 

B=12

10.8

1.8

12.5

14.3

11.09*

1.04**

2

A=19

11.5

1.3

12.7

12.8

-

-

 

B=18

12.1

1.1

13.2

8.0

12.57

1.04*

300

A=17

7.6

5.3*

12.9

44.7*

-

-

 

B=11

11.7

2.0*

13.7

14.6

13.14

1.11*

600

A=11

6.2

6.3

12.5

48.6

-

-

 

B=6

11.3

0.7

12.0

5.8

8.95**

0.79***

A: litter numbers excluding premature birth

B: A with exclusion of total litter losses

Difference from controls statistically significant at Wilcoxon test: * p<0.05, ** p<0.01, *** p<0.001

 

Group mean incidence of major malformations and minor anomalies:

Dosage (mg/kg)

Number of young

 

Examined

Affected

Total number

Mean (%)

Major malformations

0

149

1

1.3

0.2

129

0

0

2

218

0

0

300

129

2

1.4

600

68

4

5.4

Minor anomalies, gross or visceral

0

46

1

1.8

0.2

31

1

3.1

2

64

1

1.5

300

40

2

5.3

600

8

0

0

Minor anomalies, skeletal

0

102

1

1.0

0.2

98

43

39.6

2

153

57

39.1 (p<0.05)

300

87

18

22.3

600

56

55

98.5

 

Incidence of pups with extra ribs (pups with major malformations excluded):

Dosage (mg/kg)

Mean (%)

Cervical

Lumbar

0

12.6

23.1

0.2

11.6

31.3

2

24.4

34.3

300

24.5

5.7

600

21.9

13.7

 

Conclusion:

Embryotoxic effects have been observed from 300 mg/kg bw/d on. However, as these observations were accompanied by marked maternal toxicity (even maternal death at the highest dose level of 600 mg/kg bw/d) and were not significantly different from historic controls at 300 mg/kg bw/d, they were considered secondary to the toxicity of the test substance on the dam, and are therefore insufficient for a classification as embryotoxic.

Applicant's summary and conclusion

Conclusions:
The test item induced embryotoxic effects only in the presence of maternal toxicity. These effects were therefore considered to be secondary to maternal toxicity.