Reaction product of 9-Octadecenoic acid, (Z)-, sulfonated, potassium salts, hydrogen peroxide and sulfuric acid

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-08-03 to 2012-09-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Limited, Margate, UK
- Age at study initiation: 9 - 10 weeks (P)
- Weight at study initiation: 207 - 273 g (P)
- Housing: individually
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 3 - 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 23 °C
- Humidity (%): 40 - 70 %
- Air changes (per hr): 10 air changed per hour (minimum)
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
Test material dosing formulations were prepared daily by dilution of PSOA in deionised water. Dosing formulations were stored at 4 °C until use.

The dose volume (10 mL/kg) was based on the most recent body weight measurement.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Duplicate top, middle and bottom samples for each sampling time point were collected for analysis by UV-spectrometry. Samples were stored at 4 °C until analysis.

Details on mating procedure:

- Time mated female rats were used in the study that had previously been inseminated by males.
- Detection of mating referred to as Day 0

Duration of treatment / exposure:

Day 6 to Day 19 of gestation

Frequency of treatment:

Daily

Duration of test:

All surviving animals were killed on Day 20 of gestation

Doses / concentrations

Remarks:

Doses / Concentrations:
0, 5, 15, 50 mg/kg/day
Basis:
nominal conc.

No. of animals per sex per dose:

24 females per dose level

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: dose levels were selected folowing a review of the data obtained from a 28-day repeat dose toxicity study where no adverse effects were observed.

Examinations

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily
- Cage side observations included checks for mortality/moribundity

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: once pre-trial and daily during dosing period

BODY WEIGHT: Yes
- Time schedule for examinations: once pre-trial then daily throughout treatment period

FOOD CONSUMPTION: Yes
- Time schedule: daily from Day 4 of gestation,

WATER CONSUMPTION: No

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Gross necropsy consisted of external and internal examinations including the cranial, thoracic, and abdominal contents
- Representative samples of abnormal tissues, together with any other tissues considered apropriate, were fixed in neutral buffered 10 % formalin. the reproductive tract was evaluated.

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
- Live and dead foetuses: Yes
- Foetus weights: Yes
- Observations of placentae (size, colour, shape): Yes

Fetal examinations:

- External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes [half per litter]
- Skeletal examinations: Yes [half per litter]
- Head examinations: Yes [half per litter]

Statistics:

All statistical tests were two-sided and performed at the 5% significance level.
Data were analysed for homogeneity of variance using the F-Max test. If the group variances appeared homogeneous, a parametric ANOVA was used and pairwise comparisons were made using Fisher's F protected LSD method via Student's t-test. If the variances were heterogeneous, log or square root transformations were used. If the variances remained heterogeneous, then a Kruskal-Wallis nonparametric ANOVA was used and pairwise comparisons made using chi squared protection. In circumstances where it was not possible to perform the F Max test, the non-parametric ANOVA results 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:
MORTALITY
One animals dosed at 15 mg/kg/day was found dead on Day 18 of gestation. Prior to this clinical signs of pale eyes, cold skin, intermittent tremors, gasping/irregular respiration, clear discharge from the eyes and subdued behaviour were observed but the animal died before it could be euthanised. Necropsy findings included red fluid in the thoracic cavity, dark discolouration of the lungs, dark viscous material in the stomach and a hole in the trachea (2 mm diameter). This early death was considered to be due to a gavage injury and not related to treatment with the test material.

CLINICAL OBSERVATIONS
There were no treatment-related clinical observation noted in animals dosed at 0, 5 or 15 mg/kg/day. At 50 mg/kg/day one animals showed signs of piloerection on Days 19 and 20 of gestation. Subcutaneous masses observed on the ventral thorax of this animal correlated with enlarged lymph nodes found at necropsy. Another animal dosed at 50 mg/kg/day showed signs of hunched posture, piloerection and weight loss between Days 15 and 20 of gestation. At necropsy pale discoloured kidneys with pelvic dilation were noted. There were no treatment-related clinical observations or necropsy findings noted in any other animal at this dose level.

BODY WEIGHT CHANGES
There was a slight reduction in group mean body weight gain (ca. -9 %) over the course of the study at 50 mg/kg/day when compared to controls, but this change did not achieve statistical significance.

FOOD CONSUMPTION
Group mean food consumption was slightly decreased at 50 mg/kg/day when compared to controls for the duration of the study, particularly between Days 13 to 20 of gestation, but this change did not achieve statistical significance.

PREGNANCY PERFORMANCE
Pregnancy performance and foetal weights were comparable throughout the groups and slight intergroup differences in pregnancy performance and foetal weights were considered not to be related to treatment with the test material.

Effect levels (maternal animals)

1

Dose descriptor:

NOEL

Effect level:

15 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: maternal toxicity

2

Dose descriptor:

NOEL

Effect level:

50 mg/kg bw/day (nominal)

Based on:

test mat.

Basis for effect level:

other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
There was one incidence of kinked ribs at both 15 and 50 mg/kg/day, however minimally kinked ribs were present in similar instances at 50 mg/kg/day and in controls and there was no evidence of a dose-related increase in incidence or severity for this finding.
There was one incidence of omphalocele at 50 mg/kg/day but as only one animal from one litter was affected it was considered to be incidental.
Cervical remnant of thymus was present in more litters at 50 mg/kg/day than in other groups but in the same number of foetuses as for animals dosed at 5 mg/kg/day so was considered not to be significant.
Tendinous region of diaphragm locally thinned with protrusion of the median liver lobe was present at a slightly higher incidence (9 foetuses (6 litters) for minimal protrusion and 8 foetuses (5 litters) for protrusion) and severity at 50 mg/kg/day when compared to controls. This is slightly outside the background control range (up to 8 foetuses (6 litters) for minimal protrusion and 6 foetuses (5 litters) for protrusion) seen in similar studies conducted at the same test laboratory but in the absence of any other findings was considered unlikely to be of any toxicological significance.
The number of foetuses with a minor visceral abnormality/variant was slightly higher at 50 mg/kg/day when compared to controls but there was no pattern with the number of litters affected and therefore the changes are likely to be incidental and not directly related to treatment.
Several slight intergroup differences in the distribution of skeletal ossification parameters were noted, however due to the absence of any dose related response in the type and distribution of ossification parameters, these differences were considered to be incidental and not associated with treatment.
Incidences of rib costal cartilages asymmetrically aligned appeared to increase in a dose dependent manner, however the incidence seen at 50 mg/kg/day (12 foetuses from 9 litters) is still within the range of control background data (up to 13 foetal (9 litters)) obtained at the test laboratory and therefore this change is considered to be incidental. The total number of foetuses per treated group with a minor skeletal abnormality/variant was comparable to controls and no dose related response could be seen overall.

Fetal abnormalities

Abnormalities:

not specified

Overall developmental toxicity

Developmental effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Under the conditions of the study, the maternal NOEL was determined to be 15 mg/kg/day and the developmental NOEL was determined to be 50 mg/kg/day.

Executive summary:

The prenatal developmental toxicity of the test material was determined in accordance with the standardised guideline OECD 414. During the study pregnant rats were dosed test material orally, by gavage, from Day 6 to Day 19 of gestation at 0, 5, 15 and 50 mg/kg/day. Animals were regularly monitored during gestation for clinical signs of toxicity, body weight and food consumption performance and were killed on Day 20 of gestation. The status of each implantation was recorded and the viable foetuses examined for visceral and skeletal abnormalities, including the state of skeletal ossification.

Under the conditions of the study, there was no treatment-related mortality. One animal dosed at 15 mg/kg/day was found dead on Day 18 of gestation but this early death was considered to be due to a gavage injury and not related to treatment with the test material. There was a slight increase in incidences of clinical observations such as piloerection and hunched posture in the high dose group, but as the findings were transient and only 2/24 animals were affected these findings are considered not to be adverse. Slight reductions in maternal body weight and food consumption seen at 50 mg/kg/day were considered to be related to treatment, but due to the small magnitude of these changes they were considered not to be adverse.The type and distribution of foetal abnormalities and variants did not indicate any relationship to treatment with the test material. There were no differences in foetal weight which were considered to be related to treatment with the test material.

In conclusion, administration of test material by once daily oral gavage for Days 6 to 19 of gestation was well tolerated in rats at levels of 5, 15 and 50 mg/kg/day. Based on these results, the developmental no observed effect level (NOEL) was considered to be 50 mg/kg/day and the maternal NOEL was considered to be 15 mg/kg/day.