2,2',6,6'-Tetrabromo-4,4'-isopropylidenediphenol, oligomeric reaction products with Propylene oxide and n-butyl glycidyl ether

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP 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 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2,2',6,6'-Tetrabromo-4,4'-isopropylidenediphenol, oligomeric reaction products with Propylene oxide and n-butyl glycidyl ether

EC Number:

926-564-6

Cas Number:

1179964-22-7

Molecular formula:

not applicable

IUPAC Name:

2,2',6,6'-Tetrabromo-4,4'-isopropylidenediphenol, oligomeric reaction products with Propylene oxide and n-butyl glycidyl ether

Specific details on test material used for the study:

- Substance type: brominated polyether polyol
- Stability under test conditions: It is very unlikely that the test substance would react with corn oil or petroleum jelly at ambient temperature in the time scale of storage of the solutions - less than 7.5 hours. The adjuvant is mainly paraffin oil and surfactant and no reaction would be anticipated with these ingredients. I therefore consider that the formulations of the test substance in these media used in this study were stable for their period of use.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

The administration volume was 5 ml/kg body weight per day.

Analytical verification of doses or concentrations:

no

Details on analytical verification of doses or concentrations:

Analytical determination of stability and/or homogeneity of formulations were not possible due to technical reasons. For the same reason test item concentrations were not verified during the study (content check), too. Each stock formulation and dilutions of it were prepared daily and were stirred until visual homogeneity. Formulations were prepared in the presence of a second person (dual control) twice during the study.

Duration of treatment / exposure:

30 days

Frequency of treatment:

once daily

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
females: 0, 5, 15, 45 mg/kg bw
Basis:
actual ingested

Doses / concentrations 2

Remarks:

Doses / Concentrations:
males: 0, 10, 30 and 90 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

five

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale:
Dose levels were selected based on results of a previous dose range finding study with gavage administration (T2082796) in rats. Test item formulated in corn oil was first administered daily at 1000 mg/kg in a volume of 5 ml/kg body weight to 3 rats per sex. Animals lost weight, had diarrhea and had to be killed in moribund condition after 4 treatments. Gross pathologically nodal changes, discoloration and content changes of forestomach and/or cecum were seen.

Additional 3 rats per sex were dosed at 500 and 100 mg/kg daily (same formulation and administration volume). After second treatment rats showed comparable clinical symptoms at 500 mg/kg (both sexes) and at 100 mg/kg (one female).

After discontinuation of treatment for 2 days rats treated twice at 500 mg/kg were treated daily at 100 mg/kg. Rats treated twice at 100 mg/kg were treated at 30 mg/kg without discontinuation. One 500 mg/kg-female was killed in extremis on the second day of treatment discontinuation. Male rats treated at 500 then 100 mg/kg recovered, gained weight and showed no more clinical symptoms, while 100 then 30 mg/kg males stayed without symptoms. Females treated first at 500 then at 100 mg/kg lost further body weight. One of these females was killed in moribund condition, the other stopped losing body weight. Females first treated twice at 100 mg/kg then at 30 mg/kg gained weight after dose reduction and diarrhea disappeared.

Overall females were more sensitive than males. Therefore different dose schedules were chosen for the subacute study.

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes (incl. Open Field Observations (OFO))
- Time schedule: once before start and once weekly thereafter

BODY WEIGHT: Yes
- Time schedule for examinations: daily

FOOD CONSUMPTION: Yes
- Time schedule for examinations: weekly

WATER CONSUMPTION: Yes
- Time schedule for examinations: weekly

HAEMATOLOGY: Yes
- Time schedule for collection of blood: once, day 30/31
- How many animals: all dose groups incl. controls

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: once, day 30/31
- How many animals: all dose groups incl. controls

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: FOB: once, day 28 (males), day29 (females); MA: once, day 28 (males), day 29 (females)
- Dose groups that were examined: all dose groups incl. controls
- Battery of functions tested: Functional Observational Battery (FOB); Motor Activity (MA)

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (all dose groups and controls)

ORGAN Weights:
Brain, heart, liver, spleen, kidneys (both), thymus, adrenal glands (both), epididymides (both), testes (both), prostate, seminal vesicles with coagulation glands, ovaries/oviducts (both) and uterus/cervix.

Fixed organs:
Adrenals, aorta, brain (cerebrum, cerebellum, ponslmedulla), epididymides, esophagus, eyes, eyelids, extraorbital lachrymal glands, femur, harderian glands, head (with nasal and paranasal cavities), heart, intestine (duodenum, jejunum, ileum, cecum, colon, rectum and remaining intestine), kidneys, larynx, liver, lymph nodes (mandibular, bronchial/hilus, and mesenteric), lung, mamma, optical nerves, ovaries, oviducts, pancreas, pharynx, pituitary, prostate, salivary glands, sciatic nerve, seminal vesicles (incl. coagulating glands), skeletal muscle (thigh), skin (mammary and muzzle), spinal cord (cervical, thoracic, lumbar), spleen, sternum, stomach (forestomach and glandular stomach), testes, thymus, thyroids (including parathyroid glands), tongue, trachea, ureter, urethra, urinary bladder, uterus with uterine cervix, vagina, Zymbal’s glands and all organs or tissues with macroscopic findings.

HISTOPATHOLOGY: Yes (high dose group and controls)
-Adrenal gland * Oviduct*; Bone; sternum Parathyroid gland *; Bone marrow; sternum Peyer's patch; Brain (three regions) Prostate gland; Cecum Rectum; Cervix Sciatic nerve; Coagulating gland * Seminal vesicle *; Colon Skeletal muscle; Duodenum Spinal cord (three regions); Epididymis * Spleen Femur/knee joint (with bone marrow) Stomach (nonglandular and glandular); Heart Testis*; Ileum Thymus; Jejunum Thyroid gland *Kidney* Trachea. Liver Urinary bladder; Lung Uterus; Lymph node; iliac* Vagina; Lymph node; mesenteric; Macroscopic abnormalities; Ovary*
For paired organs(*); both sides were examined

HISTOPATHOLOGY: Yes (all dose groups and controls)
-Microscopic: duodenum, jejunum, ileum, cecum, colon, rectum, Peyer's patch and mesenteric lymph node

Statistics:

Statistical tests on FOB, body weights and weight gain as well as on absolute organ weights were done using the Dunnett Exact Homogeneous Test. For relative organ weights the Dunnett Exact Homogeneous Test after log. Transformation was used.
If primary food and water intake data were recorded, the calculated food/water intake per animal was evaluated using adjusted Mann-Whitney U-tests.
The Dunnett Exact Homogeneous or Heterogeneous Test, the Dunnett Exact Homogeneous Test after log. Transformation or the Bonferroni/Mann-Whitney U-test was used for clinical pathology parameters. Descriptive statistics were provided per sex, dose group and time point for all parameters that were recorded with a specified unit. This included measures of general tendency (mean and median (median not given for food and water intake)) and general variability (standard deviation, minimum and maximum) as appropriate.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Since no rat died during the study, survival was not affected by treatment with the test item.In all high dose rats (both sexes) treatment with the test item induced changed feces consistency (soft, pulpish).

Mortality:

mortality observed, treatment-related

Description (incidence):

Since no rat died during the study, survival was not affected by treatment with the test item.In all high dose rats (both sexes) treatment with the test item induced changed feces consistency (soft, pulpish).

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):

effects observed, treatment-related

Description (incidence and severity):

There was no dose and time dependent difference in water consumption in low dose rats and in mid dose females. Related to body weight mid and high dose males consumed more water. High dose females had a slightly higher water intake in the last 2 weeks.

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Clinical biochemistry findings:

no effects observed

Urinalysis findings:

not examined

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:

HAEMATOLOGY:

Mean neutrophile counts of high dose females marked as significantly higher are based on individual values within the
control rang ofrats of the same strain and age run some months before (T6082745). This
difference is thus considered as normal variation. All other means identified as significantly
different were without dose-relation and are hence considered irrelevant.

CLINICAL CHEMISTRY:
Mean ALA T activity of high dose males marked as significantly higher is without dose relation and thus considered a chance result. Creatinine concentration of mid dose males and high dose rats of both sexes was slightly but significantly lower with no dose correlation in males.


HISTOPATHOLOGY:
Minor inflammatory changes in the intestine (mainly cecum) were seen at dosages of 10, 30 and 90 mg/kg/day in males and at 15 and 45 mg/kg/day in females. Histologically, intestinal changes mostly in the cecum were seen in all mid dose group and most high dose animals. These comprised a minimall mild mononuclear cell infiltration of the cecal mucosa, in some animals associated with minimal/ mild diffuse mucosal hyperplasia. Mild mononuclear cell infiltration ofthe cecal mucosa was also observed in one single male of the low dose group. Moreover, the mucosa of other intestinal segments was also infiltrated in most high dose females and some mid and high dose males, without dose relationship. Possibly secondary to the intestinal inflammatory process a tendency towards minor unspecific histopathological changes were noted in mesenteric lymph nodes (all treated animals), although dose relationship was missing. In the Peyer´s patches of mid and high dose females vacuoles (minimal numbers, low incidence) without dose relation were seen. Because there were no surrounding reactions this finding is considered as non-adverse.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male

Basis for effect level:

other: inflammatory changes in the intestine

2

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

female

Basis for effect level:

other: inflammatory changes in the intestine

Target system / organ toxicity

Critical effects observed:

not specified

Applicant's summary and conclusion

Executive summary:

In a repeated dose oral toxicity study in rats (Wistar, OECD TG 407), the substance was adimistered via gavage to 5 rats/sex/dose at 0, 10, 30, 90 mg/kg bw (male) or 0, 5, 15, 45 mg/kg bw (female) in corn oil for 4 weeks. Up to and including 90 or 45 mg/kg bw no mortality occured. The behavior of the rats were not influenced by the treatment up to and including 90 mg/kg (males) or 45 mg/kg (females). There were no clinical findings induced by treatment with the test item in rats dosed at low and mid dose. In all high dose rats (both sexes) treatment with the test item induced changed feces consistency (soft, pulpish). Related to body weight mid and high dose males consumed more water. High dose females had a slightly higher water intake in the last 2 weeks.The body weight gain, the food intake, clinical chemistry and organ weights were not affected up to and including 90 mg/kg in males and 45 mg/kg in females. The results from Functional Observational Battery (FOB) measurements in males and females receiving up to and including 90 mg/kg bw or 45 mg/kg bw did not differ from the control animals. Motor and Locomotor Activity(MA/LMA) tests did not indicate neurotoxicity up to and including 90 mg/kg or 45 mg/kg.

At necropsy consistency changes of small and large intestine and/or cecum dilations were observed (mid and high dosed animals). Histopathological examinations revealed minor inflammatory changes in the intestine (mainly cecum, mid and high dose, both sexes, one low dosed male). Possibly related to this a tendency towards minor unspecific histopathological changes were noted in mesenteric

lymph nodes (all treated animals, no dose relation).

Therefore, under the condition of the present study, the NOAEL (no-observed-adverse-effect-level) for the test item after 4-week daily oral treatment by gavage is 10 mg/kg bw and 5 mg/kg bw for male and female rats.