Dibenzo[d,f][1,3,2]dioxaphosphepin, 6,6'-[[3,3',5,5'-tetrakis(1,1-dimethylethyl)[1,1'-biphenyl]-2,2'-diyl]bis(oxy)]bis-

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

other information

Study period:

2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guidenline and GLP study.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Remarks:

Not specified in report

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Deviations:

no

Remarks:

Not specified in report

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: EPA 712-C-00-366

Deviations:

no

Remarks:

Not specified in report

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

482-400-9

EC Name:

-

Cas Number:

138776-88-2

Molecular formula:

C52H56O6P2

IUPAC Name:

9-[(3,3',5,5'-tetra-tert-butyl-2'-{8,10-dioxa-9-phosphatricyclo[9.4.0.0²,⁷]pentadeca-1(11),2(7),3,5,12,14-hexaen-9-yloxy}-[1,1'-biphenyl]-2-yl)oxy]-8,10-dioxa-9-phosphatricyclo[9.4.0.0²,⁷]pentadeca-1(11),2,4,6,12,14-hexaene

Details on test material:

Test material information section indicated that the purity of the test material was 93.6% ± 0.27% RSD by high performance liquid chromatography, 0.1% wt. ethyl acetate by gas chromatography, with identification by nuclear magnetic resonance and high performance liquid chromatography mass spectrometry. The test material was supplied by 'The Dow Chemical Company, South Charleston, West Virginia' with the lot number VD1255T809.

Test animals

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Details on test animals or test system and environmental conditions:

The animals were 6-8 weeks old at the start of the study. The animals were housed two-three per cage in stainless steel cages, in rooms designed to maintain adequate conditions (temperature, humidity, and photocycle), and acclimated to the laboratory for at least one week prior to the start of the study. Before administration of test material, animals were stratified by body weight and then randomly assigned to treatment groups using a computer program designed to increase the probability of uniform group mean weights and standard deviations at the start of the study. Animals placed on study were uniquely identified via subcutaneously implanted transponders. Animals were provided LabDiet Certified Diet in meal form. After assignment, animals were housed one per cage in stainless steel cages. The temperature and humidity maintained were 22°C with a tolerance of ± 1°C (and a maximum permissible excursion of ± 3°C) and 40-70%, respectively. 12-hour light/dark cycle was maintained throughout the study period with air changes of 12-15 times/hour.

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

All dosing suspensions were prepared by mixing the test material in corn oil at concentrations of 0, 25, 75, or 250 mg/ml and administered at a dose volume of 4 ml/kg body weight to achieve the targeted dose levels. Dose suspensions were not adjusted for purity. Dose volumes were adjusted at least weekly based on individual body weights.
The control rats were dosed with corn oil at 4 ml/kg body weight.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dose confirmation analysis of all dose suspensions from the first mix was determined pre-exposure. The homogeneity of the low-dose and the
high-dose test suspensions was determined concurrent with dose confirmation. The method used for analyzing the test material in corn oil was
high performance liquid chromatography with ultraviolet detection. Stability of the test material in the vehicle was initiated prior to the start of the study at concentrations of 0.25, 2.5, 25 and 250 mg/mL. The test material was found to be stable for at least 14 days at concentrations of 25 and 250 mg/mL . Test suspensions were prepared and used within these stability limits.

Duration of treatment / exposure:

Animals were dosed once daily, seven days/week for 29 days.

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
100 mg/kg/day
Basis:
actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:
300 mg/kg/day
Basis:
actual ingested

Doses / concentrations 3

Remarks:

Doses / Concentrations:
1000 mg/kg/day
Basis:
actual ingested

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Details on study design:

Test material was administered to groups of five male and five female F344/DuCrl rats by gavage at targeted dose levels of 0, 100, 300, or 1000 mg/kg body weight/day in corn oil. for at least 28 days to evaluate the potential for systemic toxicity. Daily cage-side observations, daily clinical observations, weekly detailed clinical observations, ophthalmic examinations, functional tests, body weights, feed consumption, hematology,
prothrombin time , urinalysis, clinical chemistry, and selected organ weights were evaluated (4Table 1). In addition, a gross necropsy was
conducted with extensive histopathology examination of tissues.

Examinations

Observations and examinations performed and frequency:

- Cage-side examination: At least once a day, generally at the same time each day (usually in the morning).
- Clinical observations: All animals pre-exposure and weekly throughout the study.
- Detailed clinical observations (DCO): Pre-exposure and once per week throughout the study.
- The functional tests (sensory evaluation, rectal temperature, grip performance and motor activity): Pre-exposure and during the last week of the
treatment period.
- Ophthalmological examination: Pre-exposure and prior to the scheduled necropsy using indirect ophthalmoscopy.
- Body weight: Pre-exposure, twice during the first week and at least weekly during the dosing period.
- Food consumption: Twice during the first week and at least weekly
- Clinical pathology: At scheduled necropsy
- Hematology: Hematocrit (HCT), Hemoglobin (HGB) concentration, Red blood cell (RBC) count, Total white blood cell (WBC) count, Differential WBC count, Platelet (PLT) count, Reticulocyte (RET) count, Mean Corpuscular Hemoglobin (MCH), Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin Concentration (MCHC)
- Coagulation: Prothrombin time (PT)
- Clinical chemistry: Alkaline phosphatase (ALP), Alanine aminotransferase (ALT), Aspartate aminotransferase (AST),
Gamma-glutamyl transpeptidase (GGT), Albumin (ALB), Albumin/Globulin Ratio (A/G) (calculated), Cholesterol (CHOL), Creatinine (CREA), Electrolytes (NA, K, PHOS, CL and CA), Globulin (GLOB)(calculated), Glucose (GLU), Total Bile Acids (TBA), Total bilirubin (TBIL), Total protein (TP), Triglycerides (TRIG), Urea nitrogen (UN)
- Urinalysis: Color, appearance, specific gravity (refractometer) and urine volume, pH, Bilirubin, Glucose, Protein, Ketones, Blood, Urobilinogen, Microscopic examination
- Anatomic pathology: At scheduled necropsy

Sacrifice and pathology:

ORGANS EXAMINED AT NECROPSY
- Organ weights: Brain, liver, kidneys, heart, adrenals, testes, epididymides, prostate + seminal vesicles with coagulating glands (and fluids), prostate, thymus and spleen.
- Macroscopic: Major organs, all gross lesions
- Microscopic: all the organs

Other examinations:

None

Statistics:

All parameters examined statistically (feed consumption is addressed below) were first tested for equality of variance using Bartlett's test (alpha = 0.01; Winer, 1971). If the results from Bartlett's test were significant, then the data for the parameter may be subjected to a transformation to obtain equality of the variances. The transformations that were examined are the common log, the inverse, and the square root, in that order. In-life body weights were evaluated using a repeated measures (RM) analysis of variance (ANOVA), the multivariate approach, for time (the repeated factor), sex, and dose (Winer, 1971). In the RM-ANOVA, differences between the groups were primarily detected by the time-dose interaction. Terminal body weight, organ weight (absolute and relative, excluding epididymides and testes), urine volume, urine specific gravity, hematologic parameters (excluding RBC indices and differential WBC), coagulation and clinical chemistry parameters (excluding globulin and albumin/globulin ratio) were evaluated using a two-way ANOVA (Steel and Torrie, 1960) with the factors of sex and dose. Results for epididymides, testes, prostate + seminal vesicles with coagulating glands (and fluids), and prostate weights (absolute and relative) were analyzed using a one-way ANOVA. Feed consumption data were evaluated by Bartlett's test for equality of variances. DCO and sensory evaluation incidence data (scored observations only) were qualitatively analyzed. Means and standard deviations were calculated for rectal temperature, grip performance and motor activity counts. Motor activity counts were reported as their square roots to minimize problems of heterogeneity of variance and departure from normality that commonly occur from treatment

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):

no effects observed

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

no effects observed

Behaviour (functional findings):

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

liver weight increases

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

vacuolization of hepatocytes consistent with fatty change

Histopathological findings: neoplastic:

no effects observed

Details on results:

CLINICAL SIGNS AND MORTALITY: No clinical signs or deaths

DETAILED CLINICAL SIGNS AND CAGE SIDE OBSERVATIONS: No effects

FUNCTIONAL TESTS: No effects

OPHTHALMOLOGY: No effects

BODY WEIGHT AND WEIGHT GAIN: No effects

FOOD CONSUMPTION: No effects

HEAEMATOLOGY: No effects

PROTHROMBIN TIME: No effects

CLINICAL CHEMISTRY: No effects

URINALYSIS: No effects

ORGAN WEIGHTS:

LIVER: Limited to statistically significant higher absolute and relative liver weights of males and females in the 1000 mg/kg/day group, and a statistically-significant higher relative liver weight of males in the 300 mg/kg/day group.

KIDNEY: Males and females in the 1000 mg/kg/day group had statistically-identified higher mean relative kidney weight, which was interpreted to be unrelated to treatment because it was within the historical control range.

TESTES: Males in the 300 mg/kg/day group also had a statistically identified lower mean relative testes weight. This finding was interpreted to be unrelated to treatment as it lacked a dose-response relationship, was within the historical control range, and was reflective of the higher body weights of males at this dose level, relative to the controls. Furthermore, histopathology of testes did not detect any alterations.

GROSS PATHOLOGY: No effects

HISTOPATHOLOGY: NON-NEOPLASTIC: Treatment-related histopathologic changes were limited to the liver and consisted of vacuolization of hepatocytes consistent with fatty change in males and females in the 300 or 1000 mg/kg/day groups.

Effect levels

Dose descriptor:

NOEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: overall effects

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:

The no-observed-effect level (NOEL) for F344/DuCrl Rats of either sex was the targeted dose of 100 mg/kg/day test material. .

Executive summary:

Five male and five female F344/DuCrl rats per group were administered 0, 100, 300, or 1000 milligrams 6,6'-[[3,3',5,5'-tetrakis(1,1-dimethylethyl)-[1,1'- biphenyl]-2,2'-diyl] bis(oxy)]bis-dibenzo[d,f][1,3,2]-dioxaphosphepin per kilogram body weight per day (mg/kg/day) in corn oil via oral gavage for 28 days to evaluate the potential for systemic toxicity. Parameters evaluated were daily cage-side observations, daily clinical observations, weekly detailed clinical observations, ophthalmic examinations, functional tests, body weights, feed consumption, hematology, prothrombin time, urinalysis, clinical chemistry, selected organ weights, and gross and histopathologic examinations. There were no treatment-related effects in clinical signs, body weights, feed consumption, ophthalmic examinations, functional tests, hematology, prothrombin time, clinical chemistry, urinalysis parameters or gross pathologic observations. Treatment-related effects on organ weights were limited to statistically-identified higher absolute and relative liver weights of males and females in the 1000 mg/kg/day group, and a statisticallyidentified higher relative liver weight of males in the 300 mg/kg/day group. These organ weight findings corresponded to hepatocellular vacuolization (consistent with fatty change) of various regions of the liver lobules in males and females at these dose levels. All males in the 1000 mg/kg/day group had vacuolization of centrilobular/midzonal or panlobular hepatocytes consistent with a very slight or slight fatty change. Very slight fatty change in centrilobular hepatocytes was present in 2 of 5 males in the 300 mg/kg/day group. The majority of females in the 300 mg/kg/day (4 of 5 animals) and all of the females in the 1000 mg/kg/day group had periportal hepatocyte vacuolization consistent with a slight or moderate fatty change, respectively. The no-observed-effect level (NOEL) for F344/DuCrl rats of either sex was the targeted concentration of 100 mg/kg/day test material.