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Administrative data

Description of key information

Oral (OECD 408, rat): NOAEL ≥ 1000 mg/kg bw/day

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records
Reference
Endpoint:
sub-chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Limited information on detailed clinical observation parameters and results; frequency of general clinical observations not reported; no neurobehavioural examination was performed; the weight of the thymus, epididymes, ovary and uterus was not recorded; the skin, thymus, peripheral nerve, bone marrow, trachea were not preserved or histopathologically examined; no individual animal data was reported.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
Version / remarks:
adopted Sep 1998
Deviations:
yes
Remarks:
Limited information on detailed clinical observation parameters and results; no neurobehavioural examination; thymus, epididymes, ovary and uterus weight not recorded; some organs/tissues not histopathologically examined, no individual animal data
Qualifier:
according to
Guideline:
other: The Guidelines for the Testing of Chemicals (State Environment Protection Administration of China) 2004.5
Deviations:
not specified
GLP compliance:
not specified
Limit test:
no
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Beijing HFK Bioscience Co., Ltd., Beijing, China
- Age at study initiation: 6 - 7 weeks old
- Weight at study initiation: 123 - 151 (females and males)
- Diet: rodent feed (certificate No. SCXK (JING) 2009-0012, HFK Bioscience Co., Ltd., Beijing, China), ad libitum
- Water: tap water, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 25
- Humidity (%): 40 - 70
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
corn oil
Analytical verification of doses or concentrations:
no
Duration of treatment / exposure:
90 days (control and treatment groups)
90 days and 14 days post-exposure observation period (satellite control and treatment group)
Frequency of treatment:
daily, 7 days/week
Dose / conc.:
250 mg/kg bw/day (actual dose received)
Dose / conc.:
500 mg/kg bw/day (actual dose received)
Dose / conc.:
1 000 mg/kg bw/day (actual dose received)
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: the dose levels were based on the results of an acute oral toxicity study and a 28-day repeated dose oral toxicity study
- Rationale for animal assignment (if not random): the animal assignment was random unless it lead to a heterogenous weight distribution in the groups
- Rationale for selecting satellite groups: a control and 1000 mg/kg bw/day satellite group was included to assess the reversibility of treatment-related effect
- Post-exposure recovery period in satellite groups: 14 days
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily
- Cage side observations included: mortality and morbidity

DETAILED CLINICAL OBSERVATIONS: Yes, clinical signs including general condition, fur colour, lethargy, behaviour, activity level were recorded
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: prior to administration on Day 0 and weekly thereafter

FOOD CONSUMPTION:
Yes, food intake was measured weekly.

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes, blood samples were collected from the abdominal aorta
- Time schedule for collection of blood: one day after the final dose administration (main groups) and 14 days after final dose administration (satellite groups)
- Anaesthetic used for blood collection: Yes (pentobarbital sodium)
- Animals fasted: Yes, overnight
- How many animals: all animals
- Parameters examined: hemoglobin, red blood cells, hematocrit, platelet count, total white blood cells, differential white blood cells (lymphocytes, eosinophils, basophils, monocytes, neutrophils), thrombin time, prothrombin

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: one day after the final dose administration (main groups) and 14 days after final dose administration (satellite groups)
- Animals fasted: Yes, overnight
- How many animals: all animals
- Parameters examined: aspartate aminotransferase, alanine aminotransferase, creatinine, albumin, total protein, total cholesterol, glucose, urea nitrogen, alkaline phosphatase, sodium, aluminium, potassium

URINALYSIS: Yes
- Time schedule for collection of urine: at the end of the dosing period (main groups) and 14 days after final dose administration (satellite groups)
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters examined: bilirubin, glucose, nitrite, ketone, occult blood, urobilinogen, protein, pH, specific gravity, leukocyte

NEUROBEHAVIOURAL EXAMINATION: No
Sacrifice and pathology:
GROSS PATHOLOGY: Yes, all animals were subjected to a complete gross necropsy, with an examination of the external surface of the body, and of organs and tissues. The brain, heart, liver, kidneys, adrenals, spleen, thyroid gland, lungs, trachea, stomach, esophagus, duodenum, large intestine, lymph nodes (mesenteric and submaxillary), pituitary, urinary bladder, pancreas and testes were weighted.

HISTOPATHOLOGY: Yes, the following organs and tissues were collected and preserved in 4% formaldehyde for histopathological examination: brain, heart, aorta, liver, kidneys, adrenals, spleen, thyroid, lungs, esophagus, duodenum, large intestine, lymph nodes (mesenteric and submaxillary), pituitary, urinary bladder, pancreas, testes (right and left), epididymis, ovary, uterus.
Statistics:
The statistical program used was SPSS for Windows, v 11.5 (SPSS Inc., Chicago, USA). Continuous data including body weight, body weight gain, food consumption, organ weights, index of hematology and clotting, and index of blood biochemistry were analysed by using a one-way analysis of variance (ANOVA). If significance (p < 0.05) was established, group by group comparisons were performed using Dunnet's test. Count data were analysed using the Chi-square test for index of urinalysis. All analyses used two-tailed tests for a minimum significance level of 5% comparing the control to the treated groups.
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):
effects observed, treatment-related
Description (incidence and severity):
The food consumption in males in the high-dose main group was significantly reduced in Week 7, compared with the control main group. As this was the only significant difference, it is not considered to be toxicologically relevant. In females, the high-dose satellite group showed significantly lower food consumption, compared with the control satellite group, in Week 6 - 10 and Week 13 - 15, and for the mean value over the whole study period (see Table 1 under 'Any other information on results incl. tables'). The reduction over the whole study period was approximately 13%, compared with the control satellite group. However, the food consumption in the control main group was approximately 10% lower than in the control satellite group, indicating that the latter was unusually high. The food efficiency was similar between all main and satellite groups. The reduced food consumption in females is not considered to be treatment-related.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
The platelet levels in males of the high-dose main group were significantly reduced (by approximately 20%), compared with the control main group. As the standard deviation was higher in this group compared with the remaining groups, there may be individual animals' levels affecting the mean value; however, this data was not available. Because there were no other significant hematological changes, the effect was only seen in the males and as the histopathological results did not show any related effects, the result is not considered to be treatment-related. In the females of the high-dose satellite group, the platelet levels were significantly increased (by approximately 23%), compared with the control satellite group. As no similar effect was seen in the female main group, nor in the male groups, and as the histopathological results did not show any related effects, this result is not considered to be treatment-related. The prothrombin time was significantly reduced in high-dose main group males, compared with the control group. As the change was approximately 5% and the level within the historical control range (Baseline hematology and clinical chemistry values for Charles River Wistar rats - (CRL:(WI)BR) as a function of sex and age. Technical Bulletin Spring 1998, Charles River Laboratories), this effect is not considered to be toxicologically relevant. The significant changes in neutrophil and lymphocyte concentrations noted in the mid-dose main group males are considered to be an incidental effect. In females in the high-dose main group, the neutrophil percentage was increased and lymphocyte percentage decreased, both significantly, compared with the control main group. Similarly, in the female mid-dose main group the neutrophil percentage was increased and lymphocyte percentage significantly decreased. The percentages of these immune cells are interdependent. As the number of white blood cells was not affected, the variation in percentage is not likely to indicate an adverse effect on the immune system. Therefore this is not considered to be a toxicologically relevant effect. The significant increase in eosinophil percentage in female high-dose satellite animals falls within the historical control range, and no related histopathological effects were noted. This effect is therefore not considered to be toxicologically relevant. See Table 2 and 3 under 'Any other information on results incl. tables' for relevant results on haematology.
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
The aspartate aminotransferase level in males of the high-dose satellite group was significantly increased, compared with the control satellite group. In males of the high-dose main group, the alkaline phosphatase level was significantly increased, compared with the control main group. Because these enzyme level changes were specific to the male groups, and because no histopathological effects were observed in the liver, the changes are not considered to be toxicologically relevant. The creatinine level in males of the high-dose main group was significantly increased. As no increase was noted in the females and no renal histopathological effects were seen, this is not considered to be a toxicologically relevant find.
An increase in chloride levels in high-dose main group males and reduced glucose value in high-dose satellite males is similarly considered to be incidental, as no effects in females were seen and no relevant histopathological effect were reported. Changes in low- and mid-dose groups only are considered to be incidental effects.
Urinalysis findings:
effects observed, non-treatment-related
Description (incidence and severity):
The standard gravity of females in the high-dose satellite group was significantly increased. As no changes were seen in the males and no other effects were seen on the urinary parameters, this is not considered to be a treatment-related effect.
Behaviour (functional findings):
not examined
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
The absolute brain weight was significantly decreased in males of the high-dose satellite group, compared with the control satellite group. No similar effect was seen in the relative weight, or in females. Therefore this is not considered to be a toxicologically relevant effect. No effects were seen on the absolute or relative weight of other organs and tissues.
Gross pathological findings:
no effects observed
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined
Other effects:
not examined
Key result
Dose descriptor:
NOAEL
Remarks:
systemic
Effect level:
>= 1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: no toxicologically relevant effects were noted up to and including the highest dose level
Key result
Critical effects observed:
no

Table 1: food consumption and food efficiency, females

Group

Dose (mg/kg bw/day)

Total food consumption, g (mean ± SD)

Food efficiency, % (mean ± SD)

Main

0

1615.4 ± 130.4

9.85 ± 0.86

Main

250

1595.8 ± 142.2

10.68 ± 0.94

Main

500

1660.1 ± 1772

10.46 ± 0.86

Main

1000

1600.3 ± 220.3

10.79 ± 1.46

Satellite 

0

2021.0 ± 158.2

8.62 ± 0.65

Satellite

1000

1772.9 ± 176.6*

9.10 ± 1.09

* p < 0.05

 

Table 2: Haematology data, males

Group

Dose (mg/kg bw/day)

Platelet (x 10E9/L)

Prothrombin time (s)

Neutrophils (%)

Lymphocytes (%)

White blood cells (x 10E9/L)

Main

0

108.23 ± 16.16

8.33 ± 0.14

27.3

65.7

4.90 ± 1.82

Main

250

106.40 ± 13.49

8.17 ± 0.43

22.8

70.8

6.07 ± 1.69

Main

500

110.93 ± 10.62

7.99 ± 0.61

20.4*

73.5*

6.20 ± 1.66

Main

1000

90.33 ± 28.49*

7.96 ± 0.48*

23.0

71.0

6.34 ± 1.98

Satellite 

0

105.30 ± 6.25

8.88 ± 0.44

22.5

71.0

4.96 ± 1.74

Satellite 

1000

102.80 ±15.24

8.74 ± 0.64

25.0

68.6

3.83 ± 1.76

* p < 0.05

 

Table 3: Haematology data, females

Group

Dose (mg/kg bw/day)

Platelet (x 10E9/L)

Prothrombin time (s)

Neutrophils (%)

Lymphocytes (%)

White blood cells (x 10E9/L)

Main

0

108.1 ± 14.38

7.83 ± 0.42

13.8

81.2

3.81 ± 1.24

Main

250

96.18 ± 16.72

7.84 ± 0.59

17.8

75.9

3.79 ± 0.82

Main

500

92.65 ± 35.62

8.26 ± 0.59

18.5

74.1*

3.67 ± 1.02

Main

1000

103.6 ± 12.69

7.91 ± 0.53

21.9*

70.6*

4.10 ± 1.26

Satellite 

0

95.37 ± 20.87

-

24.8

69.4

2.35 ± 0.72

Satellite 

1000

123.4 ± 28.30*

-

19.6

73.7

3.04 ± 1.64

* p < 0.05

 

Table 4: Clinical chemistry, males

Group

Dose (mg/kg bw/day)

Aspartate aminotransferase

Alkaline phosphatase

Creatinine

Main

0

59.7 ± 20.3

94.5 ± 23.99

27.9 ± 4.4

Main

250

68.5 ± 11.9

76.40 ± 13.94

27.2 ± 1.9

Main

500

64.4 ± 11.5

78.90 ± 21.07

26.1 ± 1.1

Main

1000

69.7 ± 16.6

71.60 ± 23.70*

24.4 ± 4.1*

Satellite 

0

68.9 ± 7.2

82.6 ± 17.7

27.2 ± 2.5

Satellite 

1000

85.0 ± 15.5*

81.2 ± 18.2

27.7 ± 2.8

* p < 0.05

 

Table 5: Clinical chemistry, females

Group

Dose (mg/kg bw/day)

Aspartate aminotransferase

Alkaline phosphatase

Creatinine

Main

0

34.3 ± 14.2

57.20 ± 27.98

34.4 ± 2.9

Main

250

25.7 ± 4.4*

58.90 ± 18.28

29.4 ± 4.1

Main

500

25.7 ± 6.7*

46.60 ± 11.98

31.3 ± 3.8

Main

1000

26.5 ± 6.4

45.90 ± 13.35

35.6 ± 13.2

Satellite 

0

37.5 ± 13.1

36.2 ± 14.7

34.4 ± 1.7

Satellite 

1000

46.3 ± 18.0

35.3 ± 7.4

33.9 ± 4.1

* p < 0.05

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subchronic
Species:
rat
Quality of whole database:
The available information comprises an adequate and reliable study, and is thus sufficient to fulfil the standard information requirements set out in Annex VIII-IX, 8.6, of Regulation (EC) No 1907/2006.

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

A 90-day repeated dose oral toxicity study was performed according to the Chinese Guidelines for the Testing of Chemicals (State Environment Protection Administration of China) 2004.5, using a protocol similar to OECD guideline 408 (Jing, 2014). No individual animal data was included in the study report. 10 Wistar rats/sex/dose were administered 0, 250, 500 and 1000 mg/kg bw/day Reaction mass of 1,1'-(isopropylidene)bis[3,5-dibromo-4-(2,3-dibromo-2-methylpropoxy)benzene] and 1,3-dibromo-2-(2,3-dibromo-2-methylpropoxy)-5-{2-[3,5-dibromo-4-(2,3,3-tribromo-2-methylpropoxy)phenyl]propan-2-yl}benzene in corn oil once daily for 90 days via gavage. In addition, a satellite control and high-dose group of 10 rats/dose /sex was treated in parallel, with a 14-day post-exposure recovery period to assess the reversibility of treatment-related effects.

There was no mortality during the study period. No toxicologically relevant clinical signs were observed, however, only limited data was included in the study report. The body weight, body weight gain and food efficiency was comparable between the control and treatment groups (main and satellite groups). In females of the high-dose satellite group, significantly lower food consumption, compared with the control satellite group, was noted in Week 6 - 10 and Week 13 - 15, and for the mean consumption over the whole study period. The reduction over the whole study period was approximately 13%, compared with the control satellite group. However, the food consumption in the control main group was approximately 10% lower than in the control satellite group, indicating that the latter was unusually high. The food efficiency was similar between all main and satellite groups. The reduced food consumption in females is therefore not considered to be treatment-related. The platelet levels in males of the high-dose main group were significantly reduced (by approximately 20%), compared with the control main group. Furthermore, in the females of the high-dose satellite group, the platelet levels were significantly increased (by approximately 23%), compared with the control satellite group. No similar effect was seen in the male satellite group or female main group. Furthermore, no similar effect was seen in the other sex of the main, respectively satellite, group and the histopathological results did not show any related effects. Therefore the results of the platelet levels are not considered to be toxicologically relevant. The prothrombin time was significantly reduced in high-dose main group males, compared with the control group. As the change was approximately 5% and the level within the historical control range (Baseline hematology and clinical chemistry values for Charles River Wistar rats - (CRL:(WI)BR) as a function of sex and age. Technical Bulletin Spring 1998, Charles River Laboratories), this effect is not considered to be treatment-related. In females in the high-dose main group, the neutrophil percentage was increased and lymphocyte percentage decreased, both significantly, compared with the control main group. Similarly, in the female mid-dose main group the neutrophil percentage was increased and lymphocyte percentage significantly decreased. The percentages of these immune cells are interdependent. As the overall number of white blood cells was not affected, the variation in percentage is not likely to indicate an adverse effect on the immune system. Therefore this is not considered to be a toxicologically relevant effect. Other minor changes observed in haematological parameters are considered to be incidental.

The aspartate aminotransferase level in males of the high-dose satellite group was significantly increased, compared with the control satellite group. In males of the high-dose main group, the alkaline phosphatase level was significantly increased, compared with the control main group. Because these enzyme level changes were specific to the male groups, and because no histopathological effects were observed in the liver, the changes are not considered to be toxicologically relevant. An increase in the creatinine level in males of the high-dose main group, and an increase in chloride levels in high-dose main group males and reduced glucose value in high-dose satellite males is all considered not to be toxicologically relevant, as no effects in females were seen and no relevant histopathological effect were reported.

The urinary standard gravity of females in the high-dose satellite group was significantly increased. As no changes were seen in the males and no other effects were seen on the urinary parameters, this is not considered to be a treatment-related effect.

The absolute brain weight was significantly decreased in males of the high-dose satellite group, compared with the control satellite group. No similar effect was seen in the relative weight, or in females. Therefore this is not considered to be a toxicologically relevant effect. No effects were seen on the absolute or relative weight of other organs and tissues, including reproductive organs. The macroscopic inspection at autopsy and subsequent histopathological examination did not reveal any treatment-related changes. Incidental changes in the liver, lungs and kidneys were observed both in control and treated animals. In conclusion, the NOAEL for systemic toxicity is considered to be ≥ 1000 mg/kg bw/day for male and female rats.

Justification for classification or non-classification

The available data on repeated dose toxicity do not meet the classification criteria according to Regulation (EC) 1272/2008 and are therefore conclusive but not sufficient for classification.