Phosphorothioic acid, O,O-bis(2-methylpropyl) ester, sodium salt (1:1)

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:

July - Dec, 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Also according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(1995)

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O,O-diisobutyl phosphorothioate

EC Number:

610-992-2

Cas Number:

53378-52-2

Molecular formula:

C8 H18 O3 P S . Na

IUPAC Name:

Sodium O,O-diisobutyl phosphorothioate

Test material form:

other: grease-like solid

Specific details on test material used for the study:

- Name of test material (as cited in study report): AERO® 6697 Promoter
- Name: Sodium diisobutyl monothiophoshate
- CAS: 53378-52-2
- Molecular formula: C8H18O3PS.Na
- Molecular weight: 248.26
- Storage condition of test material: not indicated in the study report
- Batch no.: 294

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Kingston, New York 12484
- Age at study initiation: Approximately 6 weeks
- Weight at study initiation: male: 169-211 g; female: 147-173 g
- Fasting period before study: no data
- Housing: Animals were individually housed in stainless steel, wire mesh cages .
- Diet: Free access to certified rodent diet, no. 5002; (Meal) (PMI Nutrition International, St. Louis, Missouri)
- Water: Free access to water.
- Acclimation period: 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-24
- Humidity (%): 40-76
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

Excursions outside the specified humidity range were not considered to have affected the integrity of the study.

In-life period: 28 July - 11 Aug 1998

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The test substance was administered as received.

Dose levels: 0, 100, 500 and 1000 mg/kg/day

Dose volume: 0, 0.09, 0.45 and 0.90 mL/kg/day

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Since no solutions were prepared as the test substance was administered as received, no analyses were necessary.

Duration of treatment / exposure:

14 days

Frequency of treatment:

Once daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

500 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

1 000 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5

Control animals:

yes, sham-exposed

Details on study design:

- Fasting period before blood sampling for clinical biochemistry: overnight

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: twice pretest and weekly during the study period

BODY WEIGHT: Yes
- Time schedule for examinations: twice pretest, weekly during treatment and terminally (after fasting)

FOOD CONSUMPTION: Yes
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes (weekly)

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at test termination Day 15
- Anaesthetic used for blood collection: Yes (under light CO2/O2 anesthesia)
- Animals fasted: Yes (overnight)
- How many animals: up to 5/sex/group
- Parameters checked: According to OECD 407

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at test termination Day 15
- Animals fasted: Yes (overnight)
- How many animals: up to 5/sex/group
- Parameters checked: According to OECD 407

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Complete macroscopic postmortem examinations were performed on all animals. The examinations include examination of the external surface and all orifices; the external surfaces of the brain and spinal cord; the organs and tissues of the cranial, thoracic, abdominal and pelvic cavities and neck; and the remainder of the carcass for the presence of macroscopic morphologic abnormalities. Animals were fasted prior to scheduled sacrifices.

ORGAN WEIGHTS: Yes
Organs (indicated in Table 1 oral 14day Organs and tissues in the attached background material) were weight for all animals at the scheduled sacrifice interval.

HISTOPATHOLOGY: Yes
Microscopic examination of tissues for all animals in the control and high-dose groups and for those animals which died unscheduled deaths during the course of the study.

Statistics:

Statistical methods used see the statistical analysis in the attached background material.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Clinical signs were seen in most high-dose (1000 mg/kg bw/day) males and females beginning on Day 4 or 5. They included moist or dry rales, labored breathing, red stains on the snout, ano-genital staining, yellow/brown stains on the ventral surface, distended abdomen, and/or decreased fecal volume and food consumption.
Clinical signs seen at 500 mg/kg bw/day in one or more males/females included labored breathing, moist or dry rales, red stains on snout, distended abdomen, anogenital staining, and decreased fecal volume and food consumption.

Mortality:

mortality observed, treatment-related

Description (incidence):

One high-dose (1000 mg/kg/day) males was euthanized in a moribund condition on Day 12; two high-dose females were found dead on Day 13 or 14.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Mid- and high-dose males and females exhibited decreased body weight gains, compared to the control animals.
At the study termination, mean body weights of mid-dose males and females, were 11% and 9% lower than the mean control weight; mean body weights of high-dose males and females were 17% and 4% lower than control weights.

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

Food consumption was reduced in males at 500 and 1000 mg/kg bw/d during both weeks and in females only in the second week at 500 mg/kg bw/d.

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

Slight, statistically significant decreases, relative to control means, were seen in total erythrocyte, hematocrit and/or hemoglobin values of mid- and high-dose females. However, differences were small and not dose-related and values were within normal ranges. Therefore, these differences are not considered biologically significant.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

A sligth elevation in mean serum aspartate aminotransferase levels in the mid-dose and high-dose males and females was noted. In the males, the elevations resulted from one especially high value in each group. In the females, the differences were statistically significant. However no microscopic changes were seen in the liver. Therefore, these differences are not considered biologically significant. Blood urea nitrogen values were increased at 1000 mg/kg bw/d in both sexes (both 131% of control). Cholesterol was increased in males at 1000 mg/kg bw/d (131% of control).

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

The mean organ weights values of the test groups were generally comparable to control group values. The testes/body weight ratios of the mid- and high-dose males were statistically significantly increased compared to the control value. The kidney/body weight ratio was increased at 1000 mg/kg bw/d. However, these differences reflected the decreased body weights in these groups and are not considered biologically significant.

Gross pathological findings:

no effects observed

Description (incidence and severity):

None of the macroscopic observations were considered to be due to the administration of the test substance. Incidental, agonal or spontaneous findings were seen in control rats or rats from the various dose groups; they have been seen in laboratory-bred rats of similar age and stock used in other studies conducted in this facility and were judged not to be related to the test substance.

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

Minor inflammatory lesions in the stomach were seen in two rats given 1000 mg/kg bw/day, which were found dead or euthanized in a moribund condition. The one male which was euthanized had focal forestomach ulcers (minimal) and submucosal inflammation associated with the mucosal lesions; for females given 1000 mg/kg bw/day, one of the two females which were found dead had slight focal erosions in the glandular stomach. No changes were seen in the remaining males and females given 1000 mg/kg bw/day or in the control animals. It cannot be excluded that this finding is related to the administration of the substance, as the pH of the substance is 13 of a 0.5 g/ml aqueous solution.

Effect levels

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

food consumption and compound intake

mortality

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Conclusions:

In a 14-day oral repeated dose toxicity study with rats, the NOAEL of Aero 6697 Promoter was determined to be 100 mg/kg bw/day based on decreased body weight and food consumption at 500 mg/kg bw/day.

Executive summary:

A 14 -day oral repeated dose toxicity study with Sprague-Dawley rats (5/sex/dose) was performed with Aero 6697 Promoter, in accordance with OECD 407 (1995) and GLP principles. Rats were exposed to 0, 100, 500 and 1000 mg/kg bw/day. Based on mortality, decreased body weight gain and decreased food consumption at 500 and 1000 mg/kg bw/day, a NOAEL for the substance of 100 mg/kg bw/day was established.