Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs.

Developmental toxicity / teratogenicity

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

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1974

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The purpose of this study was to evaluate the teratogenic potential of linear alkylbenzene sulphonate (LAS) in rats. Twenty female rats/dose were divided into 5 groups and administered 0 (water), 0.2, 2.0, 300 and 600 mg/kg bw/day of test substance by oral gavage from day 6 to 15 of gestation. Throughout experiment animals were observed daily for signs of malreaction and weighed regularly. After euthanasia on day 20, their uterine content was examined for number of implantations, viable young and embryonic deaths along with ovaries, number of corpora lutea and viable pups. Body weight, incidents of external malformation, visceral and skeletal anomalies were also recorded in pups. Non parametric methods were used for statistical analysis and on the basis of adverse effects, NOAEL value was derived for maternal toxicity and teratogenicity.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Benzenesulfonic acid, C10-13-alkyl derivs., sodium salts

EC Number:

270-115-0

EC Name:

Benzenesulfonic acid, C10-13-alkyl derivs., sodium salts

Cas Number:

68411-30-3

Molecular formula:

Not applicable for UVCB

IUPAC Name:

sodium 4-undecylbenzenesulfonate

Test animals

Species:

rat

Strain:

other: CD rats

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories, Wilmington, Mass., U.S.A. and St-Aubin-les-Elbeuf, France.
- Housing: Female rats (5 per cage) were housed in opaque plastic cages.
- Diet: Spratt’s Laboratory Diet No. 1, ad libitum.
- Drinking water: ad libitum.

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

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

- Preparation of dosing solutions: Doses were prepared on daily basis as series of graded aqueous solutions for oral dosing.
- Administration of dosage: Standard volume of doses was administered orally by gastric intubation. Control animals were dosed with water.
- Duration of dosage: Doses were commenced on day 6 after detection of vaginal plug in rats and continued daily up to and including day 15 of gestation.

Analytical verification of doses or concentrations:

not specified

Details on mating procedure:

Mating was confirmed by the detection of vaginal plug in rats.

Duration of treatment / exposure:

Animals were dosed for 10 days [from Day 6 (after detection of vaginal plug) to Day 15].

Frequency of treatment:

daily from day 6 after detection of the vaginal plug to till day 15

Duration of test:

21 days

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day

Remarks:

(control)

Doses / concentrations 2

Dose / conc.:

0.2 mg/kg bw/day

Doses / concentrations 3

Dose / conc.:

2 mg/kg bw/day

Doses / concentrations 4

Dose / conc.:

300 mg/kg bw/day

Doses / concentrations 5

Dose / conc.:

600 mg/kg bw/day

No. of animals per sex per dose:

20 female rats per dose

Control animals:

yes

Details on study design:

- Dose selection rationale: Two doses formed the basis for safety evaluation (0.2 and 2.0 mg/kg bw/day) because the likely maximum human intake of detergent from ordinary kitchen use has been estimated at 0.14 mg/kg bw/day, thus providing factors of 1-2 times the human exposure level. Two further doses (300 and 600 mg/kg bw/day) were also investigated based on previous toxicity data suggesting that these would impair maternal economy and result in obvious adverse effects.

Examinations

Maternal examinations:

All animals were observed daily for signs of malreaction and were weighed regularly throughout gestation. All animals that died, and survivors at termination, were dissected and examined for macroscopic changes.

Ovaries and uterine content:

After euthanasia, uteri were dissected and examined to determine the number of:
a) Implants
b) Viable young
c) Embryonic deaths (abortion/resorption sites)

Ovaries were examined and number of corpora lutea were also recorded.

Fetal examinations:

After weighing, fetus were examined for external malformations, visceral anomalies by free and sectioning and skeletal examination was performed by alizarin staining.

Statistics:

Differences in mean values were statistically analyzed by non-parametric method i.e. Wilcoxon test.

Indices:

Mating index: (number of confirmed mating/ number of animals cohabitated) X 100

Historical control data:

In CD rats, percentage of major malformations, minor visceral anomalies and minor skeletal anomalies were recorded as 0.41%, 2.02% and 2.35%, respectively in 51349 examined fetuses.

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Toxic effects were generally associated with the gastrointestinal tract disturbances.

Dermal irritation (if dermal study):

not examined

Mortality:

mortality observed, treatment-related

Description (incidence):

Single mortality was observed at 600 mg/kg bw/day.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Retarded weight gain was observed on 600 mg/kg bw/day.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

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:

no effects observed

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not examined

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Maternal developmental toxicity

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Description (incidence and severity):

Pre-implantation embryonic losses were 18.1%, 23.2%, 36.9%, 15.6% and 20.3% at 0, 0.2, 2, 300 and 600 mg/kg bw/day, respectively.
Post-implantation embryonic losses were 2.8%, 12.4%, 5.9%, 3.6% and 3.1% at 0, 0.2, 2, 300 and 600 mg/kg bw/day, respectively.

Total litter losses by resorption:

not specified

Description (incidence and severity):

Only single litter was lost at 0.2 mg/kg bw/day but not significant as no dose response relationship was followed.

Early or late resorptions:

not specified

Dead fetuses:

no effects observed

Description (incidence and severity):

Embryonic deaths were 0.3, 0.7, 0.6, 0.4 and 0.4 at 0, 0.2, 2, 300 and 600 mg/kg bw/day, respectively.

Changes in pregnancy duration:

not specified

Changes in number of pregnant:

not specified

Description (incidence and severity):

Mating index was also comparable across all doses when compared to the control group.

Other effects:

not specified

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day

Based on:

test mat.

Basis for effect level:

other: mortality and retarded weight gain at 600 mg/kg bw/day

Maternal abnormalities

Abnormalities:

not examined

Results (fetuses)

Fetal body weight changes:

no effects observed

Description (incidence and severity):

Although the fetal weights differed significantly at 0.2 and 2 mg/kg bw/day, these changes does not represent an adverse change because there was no consistent dose relationship and were invariably due to higher mean pub weight in the test group.

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

No test substance related effect or statistically significant differences were observed.

Changes in sex ratio:

not specified

Changes in litter size and weights:

no effects observed

Description (incidence and severity):

Litter size and weights were comparable across all doses when compared to the control group.

Changes in postnatal survival:

not specified

External malformations:

no effects observed

Description (incidence and severity):

No test substance related or statistically differences in the incidence of major malformations observed even a maternally toxic dosage.

Skeletal malformations:

no effects observed

Description (incidence and severity):

Incidences of skeletal abnormalities were comparable across all doses when compared to the control group.

Visceral malformations:

no effects observed

Description (incidence and severity):

Minor visceral anomalies were increased at 600 mg/kg bw/day (not significant statistically) but same incident was also observed in control group.

Other effects:

not specified

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

300 mg/kg bw/day

Based on:

test mat.

Sex:

not specified

Basis for effect level:

other: marginal retardation of sternebral ossification at the highest dose

Fetal abnormalities

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

skeletal: sternum

Description (incidence and severity):

Marginal retardation of sternebral ossification at the highest dose level

Overall developmental toxicity

Key result

Developmental effects observed:

yes

Lowest effective dose / conc.:

600 mg/kg bw/day (nominal)

Treatment related:

not specified

Relation to maternal toxicity:

developmental effects as a secondary non-specific consequence of maternal toxicity effects

Any other information on results incl. tables

Table 1: Mating index of the maternal animals (Palmer et.al., 1975)

Dose	Number of confirmed mating	Number of animals cohabitated	Mating index %
0	15	20	75
0.2	15	20	75
2	18	20	90
300	16	20	80
600	16	19	84

Table 2: Summary of adult performance (Palmer et.al., 1975)

Observations	Number of animals at dosage (mg/kg bw/day)
	0	0.2	2	300	600
Mated	20	20	20	20	20
Died	0	0	0	0	1
Non-pregnant	5	5	2	4	3
Total litter loss	0	1	0	0	0
With viable young	15	14	18	16	16
Body weight change	-	-	-	-	retarded gain

Table 3: Group mean litter data (Palmer et.al., 1975)

Dosage (mg/kg bw/day)	Number of litters	Litter size viable young	Embryogenic deaths	Implantations	Corpora lutea	Embryonic loss %		Litter weight (g)	Fetal weight (g)
						Pre-implantation	Post-implantation
0	15 (A & B)	9.9	0.3	10.3	12.5	18.1	2.8	36.15	3.66
0.2	15 (A)	9.1	0.7	9.8	12.7	23.2	12.4	-	-
	14 (B)	9.8	0.6	10.4	12.8	18.4	6.1	37.14	3.84^a
2	18 (A & B)	8.2	0.6	8.8	13.9	36.9	5.9	31.62	3.94^b
300	16 (A & B)	9.6	0.4	10	12.4	15.6	3.6	35.72	3.78
600	16 (A & B)	10.4	0.4	10.8	13.9	20.3	3.1	37.49	3.63

A: Mean value includes all surviving animals showing evidence of implantation, including those with total litter loss

B: Mean value includes only animals bearing viable young at termination

Difference from controls statistically significant at Wilcoxon test: aP < 0.05 and bP < 0.001.

Table 4:

a)       Group mean incidence for major and minor malformations (Palmer et.al., 1975)

Dosage (mg/kg bw/day)	Number of young
	Major malformations			Minor malformations*
				Gross or visceral			Skeletal
	Examined	Affected		Examined	Affected		Examined	Affected
		Total number	Mean (%)		Total number	Mean (%)		Total number	Mean (%)
0	149	0	0	33	1	2.2	116	2	2
0.2	137	0	0	26	0	0	111	2	1.7
2	147	0	0	22	0	0	125	5	5.5
300	153	1	0.6	30	0	0	122	4	3.6
600	166	0	0	34	1	6.7	132	2	1.8

b) Group mean incidence for pups with extra ribs (Palmer et.al., 1975)

Dosage (mg/kg bw/day)	Mean percent incidences of pups with extra lumber ribs*
0	18.6
0.2	33.1
2	21.3
300	12.9
600	15.3

* Young showing major malformations excluded

Applicant's summary and conclusion

Conclusions:

Based on the results, the maternal toxicity and developmental toxicity NOAELs were determined to be 300 mg/kg bw/day based on retarded weight gain and mortality in treated females at higher dose and based on absence of major, minor and skeletal malformations at highest dose respectively.

Executive summary:

A pre-natal developmental toxicity study is conducted with C10-13 LAS, sodium salt in pregnant female CD rats. The test substance was administered to groups of 20 pregnant female rats via oral gavage at doses of 0, 0.2, 2, 300 and 600 mg/kg bw/day from gestation day 6 (GD 6) till GD 15. All animals were observed daily for clinical signs of toxicity and were weighed regularly throughout the gestation. On GD 17, animals were euthanised and uteri were examined for number of implantations, viable youngs and embryonic deaths (abortion or resorption sites). Ovaries were examined and number of corpora lutea were also recorded. Individual foetus was weighed and examined for external malformations. About one third of the foetuses were examined for visceral anomalies and remaining two thirds for skeletal anomalies. Moderate maternal toxicity was observed at the highest dose due to retarded weight gain and mortality. These effects were associated with the gastrointestinal disturbances. No instances of major, minor and skeletal malformations were observed up to the highest dose of 600 mg/kg bw/day with the exception of a marginal retardation of sternebral ossification at 600 mg/kg. Based on the results, the maternal toxicity and developmental toxicity NOAELs were determined to be 300 mg/kg bw/day based on retarded weight gain and mortality in treated females at higher dose and based on absence of major, minor and skeletal malformations at highest dose respectively (Palmer, 1975a).