Sodium O,O-di-sec-butyl dithiophosphate

Toxicity to reproduction

Administrative data

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-08-29 - 2013-04-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline 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 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O,O-diisobutyl dithiophosphate

EC Number:

258-508-5

EC Name:

Sodium O,O-diisobutyl dithiophosphate

Cas Number:

53378-51-1

Molecular formula:

C8H18NaO2PS2

IUPAC Name:

Sodium O,O-diisobutyl phosphorodithioate

Test material form:

other: 51 % w/w solution in water, stabilized with X % NaOH

Details on test material:

- Substance type: Liquid
- Physical state: Light brown liquid
- Molecular formula (if other than submission substance): C8H18NaO2PS2
- Molecular weight (if other than submission substance): 264
- Smiles notation (if other than submission substance): CC(C)COP(=S)([S-])OCC(C)C.[Na+]
- InChl (if other than submission substance): InChI=1/C8H19O2PS2.Na/c1-7(2)5-9-11(12,13)10-6-8(3)4;/h7-8H,5-6H2,1-4H3,(H,12,13);/q;+1/p-1

Test animals

Species:

rat

Strain:

other: Crl: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories,Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Age at study initiation: Males/females: Both 59 days
- Weight at study initiation: Males: 272.2 g to 299.9 g, Females: 210.4 g to 233.6 g


- Fasting period before study: 16 hours
- Housing: kept individually in MAKROLON cages (type III plus)
- Diet (e.g. ad libitum): Commercial ssniff® R/M-H V1534 (ssniff Spezialdiäten GmbH, 59494 Soest, Germany; served as food ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 6 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C ± 3°C
- Humidity (%): 55% ± 15%
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 hours light / 12 hours dark

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on exposure:

VEHICLE
- Amount of vehicle (if gavage): 10 ml/kg b.w./day

Details on mating procedure:

Sexually mature male and female rats were randomly paired for mating. Mating
was monogamous: 1 male and 1 female animal were placed in one cage during the
dark period. The female was placed with the same male until pregnancy had occurred
or 2 weeks had elapsed. Each morning the females were examined for the
presence of sperm or a vaginal plug. If findings were negative, mating was repeated.
The day of conception (day 0 of gestation) was considered to be the day
on which sperm was found. In case pairing was unsuccessful, re-mating of females
with proven males of the same group was considered. This procedure was
repeated until at least 8 pregnant dams were available for each group.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

For the analysis of the test item-vehicle mixtures samples of approx. 2 x 1 mL
were taken at the following time points and stored at ≤ minus 20°C until analysis
at LPT:
Start of treatment period Concentration and stability
Immediately after preparation of the test itemvehicle
mixtures as well as 8 and 24 hours after
storage of the test item preparations at room
temperature:
3 samples/dose level group (groups 2 to 4)
Number of samples: 3 x 3 = 9
Homogeneity
At start of administration, during (middle) administration
and before administration to the
last animal of each dose level group:
3 samples/dose level group (groups 2 to 4).
Number of samples: 3 x 3 = 9
End of treatment period Concentration
During treatment with the test item always before
administration to the last animal/dose level
group:
1 sample/dose level group (groups 2 to 4).
Number of samples: TD 26 (1 x 3) = 3
Number of samples: TD 39 (1 x 3) = 3
Sum of all samples: 24
Sum of all aliquots: 48
The samples were labelled with the study number, test item, test species, type of
sample, aliquot number, concentration, test day, sampling time and date.

Duration of treatment / exposure:

Males
The daily administration of the test item started
two weeks before mating and lasted until the
day before sacrifice (considering a minimum total
dosing period of at least 28 days).
Females
The daily administration of the test item started
two weeks before mating and lasted up to at
least day 3 of lactation.

Frequency of treatment:

once daily

Details on study schedule:

- Age at mating of the mated animals in the study: 10-11 week

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0 mg/kg bodyweight/day (control)
Basis:
actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:
60 mg/kg bodyweight/day
Basis:
actual ingested

Doses / concentrations 3

Remarks:

Doses / Concentrations:
200 mg/kg bodyweight/day
Basis:
actual ingested

Doses / concentrations 4

Remarks:

Doses / Concentrations:
600 mg/kg bodyweight/day
Basis:
actual ingested

No. of animals per sex per dose:

80 animals (40 male and 40 female rats),
10 animals/sex/group.
A sufficient number to grant at least 8 pregnant
females per group for evaluation of the F0 generation

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: See supporting study: 14-DAY DOSE-RANGE-FINDING STUDY OF IBP1-Na (DANAFLOATTM 245) BY ORAL ADMINISTRATION TO RATS

Examinations

Parental animals: Observations and examinations:

AGE SIDE OBSERVATIONS: Yes
- Time schedule: at least daily, The frequency was increased when signs of toxicity were observed.
Cageside observations included skin/fur, eyes, mucous membranes, respiratory
and circulatory systems, somatomotor activity and behaviour patterns. The
onset, intensity and duration of any signs observed were recorded.
Individual animals were observed before and after dosing at each time of dosing for
any signs of behavioural changes, reaction to treatment or illness.
In addition, animals were checked regularly throughout the working day from 7:00
a.m. to 3:45 p.m. On Saturdays and Sundays animals were checked regularly from
7:00 a.m. to 11:00 a.m. with a final check performed at approximately 3:30 p.m.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least daily, The frequency was increased when signs of toxicity were observed.
Additionally, once before the first exposure (to allow within-subject comparisons)
and once a week thereafter, detailed clinical observations were made in all animals
outside the home cage in a standard arena and at the same time, each time preferably
by observers unaware of the treatment. Signs noted included changes in
skin, fur, eyes, mucous membranes, occurrence of secretions and excretions and
autonomic activity (e.g. lacrimation, piloerection, pupil size, and unusual respiratory
pattern). Changes in gait, posture and response to handling as well as the
presence of clonic or tonic movements, stereotypies (e.g. excessive grooming,
repetitive circling), difficult or prolonged parturition or bizarre behaviour (e.g. selfmutilation,
walking backwards) were also recorded.
Dated and signed records of appearance, change, and disappearance of clinical
signs were maintained on clinical history sheets for individual animals.

BODY WEIGHT: Yes
- Time schedule for examinations: Males and females were weighed on the first day of dosing, weekly thereafter and
at termination of the study. During gestation, females were weighed on days 0, 7,
14 and 20 and within 24 hours of parturition (day 1 post-partum) and day 4 postpartum.
Body weights were recorded individually for each adult animal.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: daily

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

No test item-related premature death was noted

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

A slight reduction in body weight was noted until the end of the study on test day 38 for the male rats of the high dose group (600 mg IBP1-Na/kg b.w./day). Body weight at autopsy was reduced accordingly

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

A slight reduction in body weight was noted until the end of the study on test day 38 for the male rats of the high dose group (600 mg IBP1-Na/kg b.w./day). Body weight at autopsy was reduced accordingly

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

The histopathological examination revealed test item related changes in the forestomach from male and female rats of the intermediate and the high dose group (200 and 600 mg IBP1-Na/kg b.w./day) in form of hyperplasia and hyperkeratosis of the squamous cell epithelium, infiltration with neutrophilic granulocytes, granulation tissue and ulcerations.
Additionally, test item-related changes were noted in the liver in the form of a centrilobullar hepatocellular hypertrophy at 600 mg/kg bw/day.

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

no effects observed

Reproductive performance:

no effects observed

Effect levels (P0)

1

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: General health parameters

2

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: Reproductive parameters

Results: F1 generation

General toxicity (F1)

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

In the high dose group the mean litter weight of the male and female pups was decreased by 5.6% on lactation day 1 and by 9.6% on lactation day 4 (without statistical significance). No noticeable differences were noted for the total litter weight

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

Effect levels (F1)

Key result

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

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

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: systemic effects

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

Effects on the parental generation

 

No test item-related premature death was noted.

At the intermediate and the high dose level (200 and 600 mg IBP1-Na/kg b.w./day) a slight to extreme salivation was noted in nearly all animals, with a higher incidence at the high dose level. Piloerection and an increased water consumption were noted for a few animals of the intermediate and the high dose group.

The neurological screening revealed a reduction for the hindlimb grip strength of the male and female animals of the high dose group (600 mg test item/kg b.w./day).

A slight reduction in body weight was noted until the end of the study on test day 38 for the male rats of the high dose group (600 mg test item/kg b.w./day). Body weight at autopsy was reduced accordingly.

Examination of the haematological and biochemical parameters revealed statistically significant changes in the male and female animals of the high dose group (600 mg test item/kg b.w./day), which were considered as to be test item-related.

Macroscopic inspection at autopsy revealed test item related changes in the cardiac part of the stomach from 3 male animals of the intermediate dose group (200 mg IBP1-Na/kg b.w./day) and in the cardiac part of the stomach from 1 female animal of the high dose group (600 mg IBP1-Na/kg b.w./day).

Examination of the organ weights revealed a slightly statistically significant increase in the relative liver weight of the male rats of the high dose group (600 mg IBP1-Na/kg b.w./day).

The histopathological examination revealed test item related changes in the forestomach from male and female rats of the intermediate and the high dose group (200 and 600 mg IBP1-Na/kg b.w./day) in form of hyperplasia and hyperkeratosis of the squamous cell epithelium, infiltration with neutrophilic granulocytes, granulation tissue and ulcerations.

 

Additionally, a test item-related centrilobullar hepatocellular hypertrophy was noted In the liver from male and female animals of the high dose group (600 mg IBP1-Na/kg b.w./day).

 

Effects on reproduction parameters and organs

No test item-related influence was noted on the reproduction parameters and organs in any treatment group.

The qualitative sperm staging revealed no test item-related spermatogenic changes.

 

Effects on the development of the F1 offspring (pups)

A non-statistically significant reduction in mean litter weight of approximately 6% to 9% was noted on lactation day 1 and 4 for the male and female pups of the high dose group (600 mg IBP1-Na/kg b.w./day), which is regarded to be test item-related.

No test item related influence was noted on the survival rate of the pups.

 

The following no-observed-effect levels were established for systemic effects:

Effects on the F0-generation

NOAEL (no-observed-adverse-effect level): 200 mg IBP1-Na/kg b.w./day, p.o.

 

Effects on reproduction

NOAEL (no-observed-adverse-effect level): 600 mg IBP1-Na/kg b.w./day, p.o.

Applicant's summary and conclusion

Conclusions:

NOAEL (no-observed-adverse-effect level): 200 mg test item/kg b.w./day, p.o. based on systemic effects and 600 mg/kg bw/d based on toxicity to reproduction.

Remark: The test solution contains NaOH due to the production method.

Executive summary:

The test was performed according to OECD guideline 422 under GLP compliance. The test substance was administered orally to rats at dose levels of 60, 200 or 600 mg test item/kg b.w./day.

The following no-observed-effect levels were established for systemic effects: NOAEL (no-observed-adverse-effect level): 200 mg test item/kg b.w./day, p.o.

The following no-observed-effect levels were established for reproductive effects: NOAEL (no-observed-adverse-effect level): 600 mg IBP1-Na/kg b.w./day, p.o.