2,8,9-Trioxa-5-aza-1-silabicyclo[3.3.3]undecane, 1,1'-(dithiodi-3,1-propanediyl)bis-

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2011-10-10 to 2012-08-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate test guideline and in compliance with GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

477-700-1

EC Name:

-

Cas Number:

883794-93-2

Molecular formula:

Hill formula: C18H36N2O6S2Si2 CAS formula: C18H36N2O6S2Si2

IUPAC Name:

1-{3-[(3-{2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecan-1-yl}propyl)disulfanyl]propyl}-2,8,9-trioxa-5-aza-1-silabicyclo[3.3.3]undecane

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 6 weeks
- Weight at study initiation: male: 138-157 g, female: 126-140
- Housing: individually in stainless steel cages
-Diet: ad libitum
- Water: ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.09-27.75
- Humidity (%): 39.9-61.44
- Photoperiod (hrs dark / hrs light): 12 h light/12 h dark

IN-LIFE DATES: From day of arrival, all surviving animals were sacrificed according to necropsy plan

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

VEHICLE
- Justification for use and choice of vehicle (if other than water): common vehicle, test item is stable, well homogeneity and good suspension
- Concentration in vehicle: 0, 5, 20, 100 mg/ml
- Amount of vehicle (if gavage): 10 ml/kg animal body weight

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Test article analysis of formulation was prepared with the same method as prepared for dosing animals. Validation study had been conducted to measure concentration, homogeneity and stability of test article suspended in corn oil. Formulations were sampled after stirring more than 5 min on the stir-plate. About 3-5 ml samples were taken randomly from the top, middle and the bottom of the liquids for each dosage (about 0.6-1ml each time was taken from each layer for at least 5 times together) while stirring. The samples were analysed with HPLC.

Duration of treatment / exposure:

The animals were dosed one time every morning for a period of 28 days (7days/week).

Frequency of treatment:

daily

Doses / concentrations

Remarks:

Doses / Concentrations:
50, 200, 1000 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

5 animals each sex per group, 4 groups per dose
Additional 5 animals each sex were used in vehicle control group and in high dosage group for observation of reversibility, persistence, or delayed occurrence of toxic effects, for 14 days after dosing.

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: based on LD50 of test item >2000 mg/kg bw and requirements of OECD guideline No. 407 (03 October 2008)
- animal selection randomly by software

Positive control:

no

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: every week

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: all animals 28 days, recovery groups for another 14 days.
- for morbidity and mortality daily, one time in the morning and one time in the afternoon
- general clinical observations: one time daily, 1 h after dosing, animal conditions and toxicity findings were recorded immediately
- detailed clinical observations: prior to the first exposure and once a week during treatment

BODY WEIGHT: Yes
- Time schedule for examinations: animals were weighed before grouping and once every week during the study. Animals were fasted overnight prior to necropsy and empty stomach body weights were collected before necropsy. When dosing was finished, all animals were weighed. Recovery animals were weighed the day before necropsy.

FOOD CONSUMPTION:
The food ration was added weekly (550g+-20g, including food box weight). The food and food boxes were weighed again 48 h (48h +-1.5h) later as surplus food weight. Mean food consumption for one animal per day was calculated.

HAEMATOLOGY: Yes
- Time schedule for collection of blood: all surviving scheduled sacrificed animals at terminal necropsy
- Anaesthetic used for blood collection: Yes, CO2 (80% CO2 and 20% O2).
- Animals fasted: Yes / overnight
- How many animals: 60
- Parameters checked in table [No.1] were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: all surviving scheduled sacrificed animals at terminal necropsy
- Anaesthetic used for blood collection: Yes, CO2 (80% CO2 and 20% O2).
- Animals fasted: Yes / overnight
- How many animals: 60
- Parameters checked in table [No.1] were examined.

URINALYSIS: Yes
- Time schedule for collection of urine: in one week before necropsy, urine samples were collected from surviving animals by abdominal extrusion
- Parameters checked in table [No.1] were examined.

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: in the fourth exposure week
- Dose groups that were examined: animals in control group and high dose group
- Battery of functions tested: sensory activity / grip strength / motor activity

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table 2), all survived animals of all dose groups (control, 50, 200, 1000 mg/kg bw, recovery groups)
HISTOPATHOLOGY: Yes (see table 2), all survived animals in control- and highest dose group (1000 mg/kg bw) after 28 days and all animals of control- and of high dose group after recovery period. Additionally, lung, kidney and liver of all survived animals of 50 and of 200 mg/kg dose group were examined.

Statistics:

SPSS 17.0 software
Barlett test
Kruskal-Wallis non-parametric analyisis
Dunnett's test
ANOVA
Duncan's test
Mann-Whitney U -test
Fisher's exact test

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

no effects observed

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

During 28 days of treatment, there were no dead or moribund animals found, and no obvious test item-related signs of toxicity could be observed in both sexes at the administered dose levels. During clinical observations including functional examinations conducted at the end of the treatment no abnormalities were recorded. Normal body weight gain and food consumption in all groups were noted during the treatment period.
There were no test item-related changes seen in urinalysis, haematology and coagulation parameters.
Clinical chemistry examinations resulted in increased mean values for TP, ALB and TG in female animals dosed with 1000 mg/kg bw/day when compared with the control group. At the end of the recovery period, high dose females showed no increase of TP, ALB and TG. Therefore, these changes were considered as reversible. There were no test item-related macroscopic changes recorded for any of the tissues and organs removed during necropsy.
The absolute and relative organ weights of animals indicate that kidney and liver were affected.
Detailed analysis showed that absolute and relative kidney weights (organ to brain) of males in high dose and mid dose groups were significantly higher than those of the control group. At the end of the recovery period both absolute and relative kidney weights (organ to brain) of high dose males showed no statistically significant increase when compared with control. This indicates reversibility of these kidney weight changes.
Females showed only in high dose group weight changes of kidney and liver when compared with control. The absolute as well as the relative liver and kidney weights (organ to body and organ to brain) showed a statistically significant increase in high dose females (p<0.01). At the end of the recovery period increases of absolute and relative kidney weights (organ to brain) of lower statistically significance (p>0.05) were still present.
The results of histopathological examination showed kidney tubule hyperplasia in male and female animals (including recovery animals) of high dose group.
Fatty change of the liver and lung alveolar septum congestion were found in the control group and high dose group. Therefore, these changes were not related to the test substance.
No further significant histopathological changes of toxicological relevance were reported.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

200 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

2

Dose descriptor:

LOAEL

Effect level:

1 000 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: The NOAEL was determined based on the significant increase of kidney weight in high dose females at the end of the recovery period and the histopathological kidney changes in high dose males and femals.

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

Based on the results of the present study, obvious toxicity effects to kidneys of male and female SD rats were observed after repeated oral dosing for 28 days with the test substance at a dose of 1000 mg/kg bw/day. Absolute and relative kidney weights were increased in association with histopathological changes. Males showed also in the 200 mg/kg bw/day dose group statistically significant changes in kidney weights (absolute and relative), histopathological changes of kidneys were not significant in this group. At the end of the recovery period, statistically significant changes of kidney weights in high dose males were resolved. Therefore, these effects in males were considered to be reversible. Females showed only in the high dose group a statistically significant increase of kidney weights. At the end of the recovery period, this kidney weight increase was of lower statistical significance when compared with the end of the dosing period, which indicates reversibility of this toxicological effect. Based on the significant increase of kidney weight in high dose females at the end of the recovery period and the histopathological kidney changes in high dose males and females, the NOAEL (No Observed Adverse Effect Level) for the test substance in the rat was determined as follows: male: 200 mg/kg bw/day, female: 200 mg/kg bw/day.