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Toxicological information

Repeated dose toxicity: oral

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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:
2003
Report Date:
2003

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: Guideline for 28-Day Repeated Dose Toxicity Test in Mammalian Species (Chemical Substances Control Law of Japan)
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity in Rodents)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
other: Crj:CD(SD)IGS
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: 6 weeks
- Weight at study initiation: male average: 223 g (213 - 234 g), female average: 162 g (149 - 174 g)
- Fasting period before study: no fasting period befores study
- Housing: in metal bracket-type cage
- Diet: CRF-1 (Oriental Yeast Co., Ltd., Itabashi-ku, Japan), ad libitum
- Water: tap-water, ad libitum
- Acclimation period: 9 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 - 25
- Humidity (%): 47 - 75
- Air changes (per hr): 10 - 15
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
olive oil
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 0.05% (w/v), 0.15% (w/v), 0.5% (w/v)
- Amount of vehicle (if gavage): 10 mL/kg bw


Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Concentrations were verified with HPLC twice; once in the first week and once in the fourth week of administration. The analytical results were 94.8 - 101.3% of nominal concentration and C.V. was 0 - 0.4%. Thus, the applied concentrations were considered allowable.
Duration of treatment / exposure:
28 days
Frequency of treatment:
once daily, 7 days/week
Doses / concentrations
Remarks:
Doses / Concentrations:
5, 15 and 50 mg/kg bw/day
Basis:
other: nominal dose
No. of animals per sex per dose:
6 (main study)
6 (satellite control, mid- and high-dose group)
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: based on the results of a pre-study in rats, which were administered the test substance in concentrations of 17, 50, 150 and 450 mg/kg bw/day for 14 days. Two males of the 150 mg/kg bw/day dose group died and five deaths occurred in females and males of the 450 mg/kg bw/day dose group. In the 50 mg/kg bw/day dose group increased liver weight was observed in both sexes. In males of the 50 mg/kg bw/day dose group, higher ASAT, ALAT and cholesterol values were determined. In females of the 50 mg/kg bw/day dose group, lower haematocrit values, higher ALAT and higher cholesterol values were observed.

- Rationale for selecting satellite groups: Random

- Post-exposure recovery period in satellite groups: 14 days

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Three times a day on weekdays (before, just after and two hours after administration) and twice a day at the weekend (before and after administration) during administration period. Once a day during recovery period.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Three times a day on weekdays and twice a day at the weekend during administration period. Once a day during recovery period.
- In the hand observations: vocalization, reactivity to handling, fur condition, skin, piloerection, mucosal membranes, eye and nose secretion, palpebral closure, exophthalmos, pupil size, lacrimation, salivation, abnormal respiration
- Open field observations: posture, gait, arousal, tremor, convulsion, abnormal behaviour, grooming, rearing, urination, defication count


BODY WEIGHT: Yes
- Time schedule for examinations: day 1, 4, 7, 11, 14, 18, 21, 25 and 28 during administration. 1, 3, 7, 11 and 14 days after administration during recovery period.

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each dose-group determined and mean daily diet consumption calculated as g food/rat/day: Yes, determined on day 1, 4, 7, 11, 14, 18, 21, 25, 28
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No

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

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: the day after last administration or the day after recovery period
- Anaesthetic used for blood collection: Yes (ether)
- Animals fasted: Yes
- How many animals: all animals
- Examined parameters: red blood cells (RBC), haemoglobin concentration (Hb), hematocrit (Ht), mean corpuscular volume (MCV), mean cell haemoglobin (MCH), mean corpuscular haemoglobin concentrations (MCHC), reticulocyte concentration, platelet count, white blood cell count (WBC), differential leukocyte counts, erythroblast counts, prothrombin time (PT), activated partial thromboplastin time (APTT) and fibrinogen

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: the day after last administration or the day after recovery period
- Animals fasted: Yes
- How many animals: all animals
- Examined parameters: aspartat-aminotransferase (ASAT), alanin-aminotransferase (ALAT), lactat-dehydrogenase (LDH), gamma-Glutamyltransferase (γ-GTP), alkaline phosphatase (AIP), total protein (TP), albumin, A/G ratio, total cholesterol, triglycerided (TG), phopholipid (PL), total bilirubin, glucose, blood urea nitrogen (BUN), creatinine, Na, K, Cl, Ca and P.

URINALYSIS: Yes
- Time schedule for collection of urine: in the fourth week of administration period and in the second week of recovery period
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Checked parameters: pH, protein, ketons, glucose, occult blood, bilirubin, urobilinogen, colour, red blood cells (RBC), white blood cells (WBC), squamous cell epithelium (SEC), small round epithelial cell (SREC), cast , phosphate salts (PS) and calcium oxalate (CO)

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: in the last week of administration and recovery period
- Dose groups that were examined: all dose groups
- Battery of functions tested: sensory activity (approach response, touch response, auditory response, tail pinch response, pupillary reflex, aerial righting reflex, landing foot splay), grip strength and motor activity


Sacrifice and pathology:
GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

The following tissues were examined: cerebrum, cerebellum, spinal cord, sciatic nerve, eye, pituitary, thyroid (including parathyroid), adrenal gland, thymus, spleen, submandibular lymph nodes, mesenteric lymph nodes, heart, trachea, lungs (including bronchi), stomach, duodenum, jejunum, ileum, cecum, colon, rectum, liver, kidney, bladder, testis, epididymis, prostate, seminal vesicles, ovaries, uterus, bone and bone marrow (breastbone and femur), and thigh skeletal muscle

Organ weights were determined for brain, pituitary, thyroid (including parathyroid), thymus, heart, lung (including bronchi), liver, spleen, kidney, adrenal gland, testis, epididymis, prostate, uterus and ovary.
Statistics:
Regarding motor activity, body weight, food consumption, clinical signs, detailed clinical signs, manipulative test, grip strength, motor activity, urinalysis (quantitative results), hematological results, blood chemical results, and absolute and relative organ weights, Barlett's test was used. When equality of variance was shown (p > 0.01), Dunnett's test was applied. When equality of variance was not shown (p < 0.01), Dunnett's test with mean rank test was used.
Regarding urianalysis test (qualititative result) and histopathological findings, Mann-Whiteny's U-test was applied.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
50 mg/kg bw/day, males: significantly suppressed body weight gain (day 1-28); after recovery period no longer any effect
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Description (incidence and severity):
15 and 50 mg/kg bw/day, males: significantly decreased food consumption on day 25 of administration; after recovery period no longer any effect
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Description (incidence and severity):
5 mg/kg bw/day, females: significant increase in MCHC (not test-substance related)
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
Significant changes in several parameters (ASAT, ALAT, LDH, AlP, total cholesterin, phospholipid etc.). After recovery period, changes were no longer observed.
Urinalysis findings:
effects observed, treatment-related
Description (incidence and severity):
50 mg/kg bw/day, males: acidification of urine; reversible during recovery period
Behaviour (functional findings):
effects observed, treatment-related
Description (incidence and severity):
15 mg/kg bw/day, satellite females: significant reduced grip strength of hind limb (no dose-response relationship)
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
50 mg/kg bw/day: increase in liver weight; 50 mg/kg bw/day, satellite females: increase in liver weight (less pronounced)
Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
50 mg/kg bw/day, males: dark red discoloration of one rat liver ; after recovery period no longer any effect
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
15 and 50 mg/kg bw/day, males; 50 mg/kg bw/day females and satellite males: significant findings (e.g. vacuolation and hypertrophy of central hepatocytes, bile thrombus, pericholangitis) in liver; after recovery period in females no longer any effect
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY
Rearing was observed in males of the 5 mg/kg bw/day dose group in week 2 and 4. However, this effect was not considered test-substance related. No further effects were observed in clinical signs in any of the dose groups. No mortality occurred till the end of the study.


BODY WEIGHT AND WEIGHT GAIN
During administration period, suppressed body weight gain was observed after four days in males of the 50 mg/kg bw/day dose group; between day 25 and 28, body weight was decreased significantly. The body weight gain during day 1-28 of the high dose males was significantly depressed compared to the control males (table 1). In females of the 50 mg/kg bw/day dose group, suppressed body weight gain was observed after 14 days, but the difference compared to the control group was not significant. During recovery period, a significant body weight gain increase was observed in male and female rats, which received 50 mg/kg bw/day for 28 days (table 1). Thus, after the recovery period, the differences in body weight between high dose and control animals were no longer observed.
No effects were noted in the low and mid dose group.


FOOD CONSUMPTION
Decreased food consumption was observed in males of the 50 mg/kg bw/day group from day 21 to day 28 of administration. The difference at day 25 was significant from control animals (high dose males: 18 ± 2 g; control males: 21 ± 2 g). Significantly decreased food consumption (18 ± 2 g) was also observed in males of the 15 mg/kg bw/day group at day 25. However this change in the 15 mg/kg bw/day group was temporarily and it was indicated that this change was not caused by the test substance. No effects were noted in the rats of the 5 mg/kg bw/day group. After recovery period, there were no longer any differences between control and treated animals.


HAEMATOLOGY
No test substance-related effects were observed in haematological examinations in any of the dose groups. Significant higher mean corpuscular haemoglobin concentrations (MCHC) were observed in females of the 5 mg/kg bw/day dose group (low dose females: 34.9% ± 0.7%; control females: 33.7 ± 0.4%). However, this change was not test substance-related due to lack of dose-response relationship.


CLINICAL CHEMISTRY
Blood chemistry examination in males of the 50 mg/kg bw/day dose group revealed significant increases in ASAT (high dose males: 125 ± 65 IU/L, control males: 63 ± 6 IU/L), ALAT (high dose males: 119 ± 86 IU/L, control males: 26 ± 6 IU/L), LDH (high dose males: 101 ± 69 IU/L, control males: 49 ± 15 IU/L) and total cholesterol (high dose males: 56 ± 7 mg/dL, control males: 44 ± 4 mg/dL) and phospholipid (high dose males: 100 ± 12 mg/dL, control males: 79 ± 6 mg/dL) and a significant decrease in inorganic phosphorus (high dose males: 6.8 ± 0.4 mg/dL, control males: 7.8 ± 0.5 mg/dL). In females of the highest dose group significant increases in AlP (high dose females: 540 ± 104 IU/L, control females: 373 ± 96 IU/L), total cholesterol (high dose females: 65 ± 8 mg/dL, control females: 53 ± 9 mg/dL) and phospholipid (high dose females: 110 ± 9 mg/dL, control females: 93 ± 10 mg/dL) were observed. Decrease of sodium was revealed in males receiving 15 and 50 mg/kg bw/day (high and mid dose males: 142 ± 1 mmol/L, control males: 144 ± 1 mmol/L). Increase in triglycerides was revealed in males of the 5 mg/kg bw/day dose group, however no increase in triglycerides was determined for the mid and high dose males (no dose-response relationship). Although a decrease in creatinine was observed in all exposed males (high dose males: 0.29 ± 0.03 mg/dL, mid dose males: 0.30 ± 0.03 mg/dL, low dose males: 0.30 ± 0.02 mg/dL, control males: 0.35 ± 0.05 mg/dL) and a decrease in total bilirubin in males of the 15 mg/kg bw/day dose group (mid dose males: 0.04 ± 0 mg/dL, control males: 0.06 ± 0.01 mg/dL) and in females of the 50 mg/kg bw/day dose group (high dose females: 0.02 ± 0 mg/dL, control females: 0.05 ± 0.01 mg/dL), these changes were not considered of toxicological relevance. After the recovery period, the changes in blood chemistry examination were no longer observed. An increase in total bilirubin in females of the 50 mg/kg bw/day after recovery period was considered as a physiological change (high dose females: 0.06 ± 0.01 mg/dL, control females: 0.05 ± 0.01 mg/dL).


URINALYSIS
Acidification of urine was observed in males of the 50 mg/kg bw/day dose group at the end of the exposure period. A significant increase in protein positive animals were observed in males of the mid-dose group, but this change was not dose-response-related. No further effects were noted in any of the dose groups within the treatment period. After the recovery period, there was no more a significant difference in the dosed animals compared to control rats.


NEUROBEHAVIOUR
In females of the 15 mg/kg bw/day dose group, the grip strength of the hind limb was significantly less compared to the control animals in the second recovery week (mid dose females: 656 g, control females: 808 g). However, no dose-response relationship was found. In the fourth week of administration females of the 15 mg/kg bw/day dose group revealed significantly higher motor activity during the first ten minutes compared to control rats. However, thereafter no significant differences were noted till 60 min and no dose–response relationship was seen. No significant differences were noted in the low and high dose group compared to control animals.


ORGAN WEIGHTS
Significant increases in relative liver weight were observed in males receiving 50 mg/kg bw/day and increases in relative and absolute liver weights were found in females of the high dose group after the end of the treatment period (table 2). After recovery period a significant increase in relative liver weight in females of the high dose group was still present, however the degree was reduced (table 2). This increase was not considered adverse, since there were no findings in liver histopathology and changes in clinical biochemistry or haematology at the end of recovery. A significant decrease in absolute and relative liver weight in males of the 15 mg/kg bw/group was noted after recovery period. However, this effect is not dose-response-related.

The following changes (table 2) in the high dose group (50 mg/kg bw/day) were caused by suppressed body weight gain: increases in relative brain weight in females and males, decreases in absolute thymus weight in males, decrease in absolute spleen weight in females and males, increases in relative kidney weight in males and increase in relative epididymides weight in males.


GROSS PATHOLOGY
Dark red discoloration of the liver was observed in one male of the 50 mg/kg bw/day dose group.
The following changes occurred accidentally: enlarged liver in one male administered 15 mg/kg bw/day, unilateral smaller epididymis in one male administered 5 mg/kg bw/day, unilateral cysts in kidneys in one female administered 50 mg/kg bw/day, unilateral smaller testis in one male administered 5 mg/kg bw/day and unilateral agenesis in parathyroid in one female of the control group. No abnormalities were observed in the recovery group in both sexes.


HISTOPATHOLOGY: NON-NEOPLASTIC
After administration:
Test substance-related effects were observed in the liver of both sexes (table 3). Slight and moderate hypertrophy of central hepatocytes was noted in all males and 5 females of the high dose group, in all males of the mid dose group and in 3 males of the low dose group. Slight and mild pericholangitis was found in 5 males and one female of the 50 mg/kg bw/day dose group. Slight and mild bile thrombus was observed in 5 males and one female administered 50 mg/kg bw/day. Hypertrophy of bile ductal cell was seen in 3 males of 50 mg/kg group. Vacuolation of central hepatocyte was noted in 2 males of 5 mg/kg bw/day and 5 males of 50 mg/kg bw/day group. In one male of the high dose group single cell necrosis was found.

The following changes were not regarded as test substance-related effects but occurred accidentally: slight focal necrosis in liver each in one male of the control and 50 mg/kg bw/day group, slight liver microgranuloma in 2 females of control and in one female of 5 mg/kg bw/day group, seminiferous tubular atrophy in the testis and no sperm in lumen of epididymis in one male of the low dose group, cyst in kidney in one female of 50 mg/kg bw/day group, tubular basophila in kidney in two males and one female of the control group and two females of the 50 mg/kg bw/day group, slight lymphocytic cell infiltration in prostate in three males of control and one male of 50 mg/kg bw/day group, slight focal hyperplasia of acinar cell in prostate in one male of control group, and slight necrosis of muscle fiber in one male of the control group.

After recovery period:
In females of the high dose group no longer any liver effect was noted after recovery period. In addition single cell necrosis and vacuolation of central hepatocytes were no longer observed in male rats. For the change in hypertrophy of central hepatocytes, bile thrombus, pericholangitis and hypertrophy of bile duct cells the frequency or degree were reduced (table 4). Hypertrophy of central hepatocytes, slight pericholangitis and hypertrophy in bile ductal cell was found each in 3 males of the 50 mg/kg bw/day group. Slight and mild bile thrombus was noted in 5 males of the high dose group. Eosinophilic inclusion bodies, seen in 2 males of the 15 mg/kg bw/day and in 4 males of 50 mg/kg bw/day group and microgranulomas, which reflect restoration, were found in the central region. Thus, reversibility of the changes was suggested.

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
15 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
other: in the high dose group histopathological findings in liver were observed at the end of the recovery period
Dose descriptor:
LOAEL
Effect level:
50 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
other: histopathological findings in liver were observed at the end of the recovery period
Dose descriptor:
NOAEL
Effect level:
>= 50 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: see 'Remark'

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Table 1: Effects on body weight and body weight gain 

control

5 mg/kg bw/day

15 mg/kg bw/day

50 mg/kg bw/day

males

females

males

females

males

females

males

females

Body weight gain day 1-28

199 ± 22

96 ± 12

198 ± 20

103 ± 15

194 ± 12

93 ±17

164** ± 29

82 ± 15

Body weight gain recovery period day 1-14

44 ± 9

24 ± 5

--

--

48 ± 8

27 ± 8

66** ± 12

38** ± 6

Body weight on day 14 of recovery period

487 ± 36

289 ± 8

--

--

461 ± 49

290 ± 26

470 ± 36

287 ± 21

**significantly different from control group (p <0.01)

 

Table 2: Effects on organ weights

Organ

 

control

5 mg/kg bw/day

15 mg/kg bw/day

50 mg/kg bw/day

males

females

males

females

males

females

males

females

Liver

[g or g/100 g bw]

absolute (day 28)

11.7 ± 1.28

7.07 ± 0.56

12.91 ± 1.63

7.30 ± 0.68

13.12± 1.72

6.96 ± 0.54

12.87 ± 1.54

8.06* ± 0.81

relative (day 28)

2.98 ± 0.20

2.88 ± 0.10

3.21 ± 0.25

2.88 ± 0.12

3.24 ± 0.24

2.93 ± 0.07

3.64** ± 0.26

3.55** ± 0.15

absolute (after recovery)

13.16 ± 1.76

6.88 ± 0.36

--

--

10.80* ± 1.58

7.00 ± 0.68

12.05 ± 1.38

7.54 ± 0.89

relative (after recovery)

2.86 ± 0.24

2.55 ± 0.11

--

--

2.49* ± 0.34

2.59 ± 0.14

2.71 ± 0.16

2.77* ± 0.13

Brain

[g or g/100 g bw]

absolute (day 28)

2.12 ± 0.09

1.92 ± 0.10

2.09 ± 0.07

1.93 ± 0.12

2.04 ± 0.07

1.94 ± 0.04

2.08 ± 0.03

1.96 ± 0.06

relative (day 28)

0.54 ± 0.02

0.78 ± 0.05

0.52 ± 0.03

0.76 ± 0.05

0.51 ± 0.02

0.82 ± 0.07

0.59* ± 0.05

0.87* ± 0.05

Thymus

[mg or mg/100 g bw]

absolute (day 28)

446 ± 101

423 ± 67

412 ± 34

438 ± 106

468 ± 68

377 ± 75

342 ± 35*

378 ± 82

relative (day 28)

114 ± 23

171 ± 19

103 ± 11

172 ± 29

116 ± 10

159 ± 29

97 ± 9

166 ± 31

Spleen

[g or g/100 g bw]

absolute (day 28)

0.72 ± 0.10

0.54 ± 0.09

0.64 ± 0.09

0.50 ± 0.04

0.66 ± 0.10

0.47 ± 0.03

0.54** ± 0.04

0.44* ± 0.08

relative (day 28)

0.18 ± 0.02

0.22 ± 0.03

0.16 ± 0.02

0.20 ± 0.02

0.17 ± 0.02

0.20 ± 0.02

0.15 ± 0.02

0.19 ± 0.03

Kidney

[g or g/100 g bw]

absolute

(day 28)

2.66 ± 0.14

1.78 ± 0.15

2.61 ± 0.18

1.76 ± 0.07

2.75 ± 0.40

1.71 ± 0.13

2.72 ± 0.03

1.82 ± 0.16

relative

(day 28)

0.68 ± 0.04

0.72 ± 0.04

0.65 ± 0.03

0.70 ± 0.04

0.68 ± 0.06

0.72 ± 0.05

0.78** ± 0.05

0.80 ± 0.09

Epididymis

[mg or mg/100 g bw]

absolute

(day 28)

827 ± 59

--

845 ± 73

--

876 ± 68

--

847 ± 64

--

relative

(day 28)

211 ± 13

--

210 ± 14

--

218 ± 17

--

241* ± 27

--

* significantly different from control group (p <0.05)

** significantly different from control group (p <0.01)

 

Table 3: Histopathological findings in the liver after 28 days (all animals (6 per sex) of each dose group were examined)

Liver

control

5 mg/kg bw/day

15 mg/kg bw/day

50 mg/kg bw/day

males

females

males

females

males

females

males

females

Vacuolation, hepatocyte, central

0

0

2

0

0

0

5**

0

Necrosis, single cell

0

0

0

0

0

0

1

0

Hypertrophy, bile ductal cell

0

0

0

0

0

0

3 (2 slight + 1 mild)

0

Bile thrombus

0

0

0

0

0

0

5**(2 slight + 3 mild)

1

Pericholangitis

0

0

0

0

0

0

5**

1

Hypertrophy, hepatocyte, central

0

0

3

0

6**

0

6**

5**

** significantly different from control group (p <0.01)

 

 

Table 4: Histopathological findings in the after recovery period (all male animals and females of control and high dose group were examined)

Liver

control

15 mg/kg bw/day

50 mg/kg bw/day

males

females

males

females

males

females

Eosinophilic inclusion body

0

0

2

--

4*

0

Microgranuloma

0

1

3

--

3

0

Hypertrophy, bile ductal cell

0

0

0

--

3 (slight)

0

Bile thrombus

0

0

0

--

5** (3 slight + 2 mild)

0

Pericholangitis

0

0

0

--

3

0

Hypertrophy, hepatocyte, central

0

0

0

--

3

0

* significantly different from control group (p <0.05)

** significantly different from control group (p <0.01)

Applicant's summary and conclusion

Conclusions:
In a subacute toxicity study in rats receiving 5, 15 and 50 mg/kg bw/day for 28 days the liver was identified as target organ. The NOAEL is considered to be 15 mg/kg/day for males based on the histopathological changes in the liver (bile thrombus, hypertrophy of hepatocytes and bile ductal cells, pericholangitis, eosinophilic inclusion bodies) still present after recovery period in the 50 mg/kg bw/day group. A NOAEL of ≥50 mg/kg bw/day for females is applied for females due to no adverse effects observed after recovery period.