Registration Dossier

Administrative data

Endpoint:
sub-chronic toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented and reliable GLP and guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity in Rodents)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.3100 (90-Day Oral Toxicity in Rodents)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: solid
Details on test material:
Please refer to confidential details on test material.

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Raleigh, NC, United States
- Age at study initiation: 38 to 40 days old
- Weight at study initiation: males: 142 g to 166 g on the day of randomization and assignment to study; females: 121 g to 145 g on the day of randomization and assignment to study
- Housing: individual housing
- Diet: Certified Rodent Diet® #5002, ad libitum
- Water: Automatic watering access system, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19-25°C
- Humidity: 30-70%
- Photoperiod: 12-hours light/ 12-hours dark

IN-LIFE DATES: From: 2012-05-1 To: 2012-08-02

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
polyethylene glycol
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Analytical method
Formulation analyses were performed by HPLC.

Concentration and homogeneity analysis
Concenctation analysis was performed in first and last preparation of all dose groups. Homogeneity analysis was performed for the low and high dose group for the first preparation only.

Stability analysis
Stability analyses were performed and demonstrated that the test item is stable in the vehicle at room temperature and protected from light for 24 hours and under refrigerated conditions (2°C to 8°C) and protected from light for 10 days at concentrations bracketing those used in the present study.

Duration of treatment / exposure:
From Day 1 through 90 of the study
Frequency of treatment:
once daily
Doses / concentrations
Remarks:
Doses / Concentrations:
100, 300, 1000 mg/kg bw/day
Basis:
actual ingested
No. of animals per sex per dose:
10 rats
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale:
The oral (gavage) route was selected because the exact dose can be accurately administered and to maximize systemic exposure. Dose levels were selected on the basis of a range-finding study described under "Any other information on material and methods incl. tables".

Examinations

Observations and examinations performed and frequency:
MORTALITY
The rats were assessed for viability at least twice daily during the study.

CAGE SIDE OBSERVATION
The rats were observed for general appearance twice during the acclimation period, daily before each administration during the dose period, and once on the day of euthanasia.

POSTDOSE OBSERVATIONS
Postdose observations were conducted once between 1 and 4 hours after dose administration, and at the end of the normal working day.

DETAILED CLINICAL OBSERVATION
Detailed clinical observations were conducted once before the first dose and at least once weekly thereafter. Detailed clinical observations were not conducted on the week that Functional Observation Battery assessments were performed. These observations were made outside the cage in a standard arena at the same time each day of conduct.

BODY WEIGHTS
Body weights were recorded on the day after arrival, twice during acclimation, daily during the dose period, and at euthanasia (terminal weight). Additional body weights were recorded on days of behavioral evaluations.

FOOD CONSUMPTION
Food consumption values were recorded on the day after arrival, twice during acclimation, weekly during the dose period, and on the day prior to euthanasia (food remaining).

OPHTHALMOSCOPIC EXAMINATION
Ophthalmoscopic examinations were performed once prior to initiation of the dose period and once prior to euthanasia. Indirect ophthalmoscopy was used to examine visible ocular structures (including lens and fundus oculi).

CLINICAL PATHOLOGY
Blood samples for clinical pathology examinations including assessment of hematology and clinical chemistry parameters were collected under isoflurane/oxygen anestesia on the day of scheduled necropsy from all rats after an overnight fasting period.

HEMOTOLOGY
Blood samples were analyzed for the parameters specified below:
Red blood cell count,
Hemoglobin concentration,
Hematocrit,
Mean corpuscular volume,
Mean corpuscular hemoglobin concentration,
Mean corpuscular hemoglobin,
Reticulocyte count (absolute),
Mean platelet volume,
Platelet count,
White blood cell count,
Neutrophil count,
Lymphocyte count,
Monocyte count,
Eosinophil count,
Basophil count,
Large unstained cells,

Coagulation
Plasma was analyzed for the parameters listed below:
Activated partial thromboplastin time,
Fibrinogen,
Prothrombin time

Bone Marrow Smear Evaluation
Bone marrow smears (3 slides/animal) were collected and prepared

CLINICAL CHEMISTRY
The serum/plasma was analyzed for the parameters specified below:
Alanine aminotransferase,
Aspartate aminotransferase,
Alkaline phosphatase,
Gamma-glutamyltransferase,
Total bilirubin,
Urea nitrogen,
Creatinine,
Calcium,
Phosphorus,
Bile acids,
Total protein,
Albumin,
Globulin,
Albumin/globulin ratio,
Glucose,
Cholesterol,
Triglycerides,
Sodium,
Potassium,
Chloride

URINALYSIS
Urine samples were collected from female rats on study overnight from the end of Day 90 to the morning of scheduled euthanasia, Day 91. Urine samples were processed and analyzed for the parameters listed below:
Color,
Clarity,
Specific gravity,
Microscopic evaluation of urine sediment,
Total Volume,
pH,
Protein,
Glucose,
Bilirubin,
Ketones,
Nitrites,
Leukocytes,
Blood,
Urobilinogen

NEUROBEHAVIOURAL EXAMINATION
The Functional Observation Battery (FOB) was conducted during week 12 by an observer unaware of the group assignment of the rat. The observer examined the rat in its home cage, while handling the animal, and/or in an open field to assess parameters including, but not limited to the following:

Lacrimation, salivation, palpebral closure, prominence of the eye, pupillary reaction to light, piloerection, respiration, urination, and defecation (autonomic functions)

Sensorimotor responses to visual, auditory, tactile, and painful stimuli (reactivity and sensitivity)

Reactions to handling and behavior in the open field (excitability)

Gait pattern in the open field, severity of gait abnormalities, air righting reaction, visual placing response, and landing foot splay (gait and sensorimotor coordination).

Forelimb and hindlimb grip strength

Abnormal clinical signs, including but not limited to convulsions, tremors, and other unusual behavior, hypotonia or hypertonia, emaciation, dehydration, unkempt appearance, and deposits around the eyes, nose or mouth

MOTOR ACTIVITY
During the motor activity assessment, the movements of each rat were monitored by a passive infrared sensor mounted outside a stainless steel wire-bottomed cage (40.6 x 25.4 x 17.8 cm). Each test session was 1.5 hours in duration, with the number of movements and time spent in movement tabulated at each 5-minute interval. The apparatus monitored a rack of up to 32 cages and sensors during each session. Groups were counterbalanced across testing sessions and cages.

ESTROUS CYCLE EVALUATION
Estrous cycles were evaluated by examining the vaginal cytology of samples obtained by vaginal lavage. Vaginal lavage samples were collected daily for the last 28 consecutive days of the dose period, as well as on the day of euthanasia.
Sacrifice and pathology:
EUTHANASIA
Rats were euthanized by an intravenous injection of sodium pentobarbital into the inferior vena cava, following blood sample collection under isofluorane/oxygen anesthesia.

NECROPSY, GROSS PATHOLOGY
All rats surviving to scheduled euthanasia were subjected to a complete necropsy examination, which included evaluation of the carcass and musculoskeletal system; all external surfaces and orifices; cranial cavity and external surfaces of the brain; and thoracic, abdominal, and pelvic cavities with their associated organs and tissues. Images were generated for illustration of or consultation on gross observations. Generation of such images was documented.

ORGAN WEIGHTS
The organs identified for weighing in Table 1 in the section "Any other information on materials and methods incl. tables" were weighed at necropsy for all scheduled euthanasia animals. Organ weights were not recorded for the female rats found dead or euthanized in poor condition or in extremis. Paired organs were weighed together with the exception of the epididymis and testis. Organ to body weight ratio (using the terminal body weight) and organ to brain weight ratios were calculated.

HISTOPATHOLOGY
Tissues in (see Table 1 in the section "Any other information on material and methods incl. tables") from all rats were embedded in paraffin, sectioned, mounted on glass slides, and stained with hematoxylin and eosin. Histopathological evaluation was performed by a board-certified veterinary pathologist. Tissues were examined from all rats assigned to Groups 1 and 4, as well as any rats that were euthanized prior to scheduled termination or found dead. All gross lesions were examined histologically. Due to lesions observed in the rats in Group 4 which were attributed to the test substance, the liver was also examined histologically in the rats assigned to the 100 and 300 mg/kg bw/day dose groups.
Other examinations:
MALE REPRODUCTIVE ASSESSMENT
To assess the potential toxicity of the test substance on the male reproductive system, the endpoints listed below were evaluated for all male rats. For males with a unilateral abnormality in the testis and/or epididymis, the fertility samples and corresponding weights were taken from the unaffected side and the organs from the side with the abnormality were retained for possible histopathological examination.

SPERM MOTILITY
Sperm motility was evaluated using computer-assisted sperm analysis (CASA). Motility was evaluated following dispersion, into an appropriate medium, of sperm from each vas deferens.

SPERM CONCENTRATION
A homogenate was prepared from the left cauda epididymis after weighing for evaluation to determine sperm concentration (sperm per gram of tissue weight). Sperm concentration was evaluated using CASA.

SPERM MORPHOLOGY
The remaining portion of the left cauda epididymis was used to manually evaluate sperm morphology. Sperm morphology evaluations included the following: 1) determination of the percentage of normal sperm in a sample of at least 200, where feasible; and 2) qualitative evaluation of abnormal sperm.

SPERMATID COUNTS
The left testis was used for evaluation of testicular spermatid concentration via CASA. The left testis was weighed (both before and after removal of the tunica albuginea) and then homogenized. A sample from the resulting homogenate was stained with an IDENT Stain Kit from Hamilton Thorne Research, and a slide was prepared for analysis. Ten fields were analyzed to determine testicular spermatid concentration (spermatids per gram of tissue weight).
Statistics:
Please refer to the section "Any other information on material and methods incl. tables".

Results and discussion

Results of examinations

Details on results:
CLINICAL SIGNS AND MORTALITY

Male rats

All male rats survived until scheduled euthanasia.

Clinical signs attributed to administration of the test substance were noted at 300 and 1000 mg/kg bw/day. Urine stained abdominal fur occurred at 300 and 1000 mg/kg bw/day and achieved statistical significance (p ≤ 0.01) at 1000 mg/kg bw/day, in comparison with the control group. Dehydration occurred in all groups. However, the numbers of animals affected with the clinical sign were higher at 300 and 1000 mg/kg bw/day and achieved statistical significance (p ≤ 0.01) in each of these dose groups, in comparison with the control group. The number of animals affected with this clinical sign in the 100 mg/kg bw/day group was comparable to the control group. Excess salivation occurred in all groups, including the control group. However, the numbers of animals affected were slightly higher at 300 and 1000 mg/kg bw/day but reached no statistical significance, in comparison with the control group. The number of animals affected with this clinical sign in the 100 mg/kg bw/day group was lower in comparison with the control group.

Female rats

No deaths were attributed to administration of the test substance at dose levels as high as 1000 mg/kg bw/day.

Mortality occurred in 1 female rat at 300 mg/kg bw/day that was found dead on Day 68 and in 1 female rat in the 100 mg/kg bw/day group that was euthanized due to adverse clinical condition on Day 58. Both incidences of mortality were not attributed to the treatment with the test item due to the lack of a dose-response relationship. All other female rats survived until scheduled euthanasia.

Dehydration occurred at 100, 300, and 1000 mg/kg bw/day and achieved statistical significance (p ≤ 0.01) in each dose group, in comparison with the control group. Urine stained abdominal fur occurred at 100, 300, and 1000 mg/kg bw/day and achieved statistical significance (p≤0.01) at 300 and 1000 mg/kg bw/day in comparison with the control group. Only 2 animals were affected at 100 mg/kg bw/day, and the incidence did not achieve statistical significance. Slight excess salivation occurred at 300 and 1000 mg/kg bw/days and achieved statistical significance (p≤ 0.01) at 1000 mg/kg bw/day.

DETAILED CLINICAL OBSERVATION

Male rats

Clinical signs attributed to administration of the test substance occurred at 300 and 1000 mg/kg bw/day during once weekly detailed clinical examinations and were generally consistent with those observed during daily observations. Urine stained abdominal fur occurred at 300 and 1000 mg/kg bw/day and achieved statistical significance (p ≤ 0.01) at 1000 mg/kg bw/day. Dehydration (based on skin turgor) occurred at 300 and 1000 mg/kg bw/day and achieved statistical significance (p ≤ 0.01) in both groups. Rales were noted in 3 male rats at 1000 mg/kg bw/day. Although the number affected with this clinical sign during the weekly detailed clinical examinations was higher than the number in the control group, this clinical sign was not attributed to administration of the test substance because it occurred also in one control male, and was present in all groups at the daily clinical observations without dose-dependency.

Female rats

Clinical signs observed during once weekly detailed clinical examinations were generally consistent with those observed during daily observations. Urine stained abdominal fur occurred at 100, 300 and 1000 mg/kg bw/day and achieved statistical significance (p ≤ 0.01) at 300 and 1000 mg/kg bw/day. The number of animals affected with ungroomed coat and mild dehydration (based on skin turgor) at 1000 mg/kg bw/day was significantly increased (p ≤ 0.01). Slight excess salivation occurred in 2 animals at 1000 mg/kg bw/day and was attributed to administration of the test substance. Although the number of affected animals at 1000 mg/kg bw/day was only slightly higher than the control group number during the weekly detailed clinical examinations, the incidence of the clinical sign during daily clinical observations demonstrated a dose-dependent pattern of effect and achieved statistical significance. The number of animals affected with soft or liquid feces in the control group was higher, and as a result, the low incidence or lack of this clinical sign in the groups treated with the test substance achieved statistical significance (p ≤ 0.01); however, this finding was considered not to be compound-related.

BODY WEIGHT AND WEIGHT GAIN

Male rats

Mean body weight gains were unaffected by administration of the test substance at 100 and 300 mg/kg bw/day. Mean body weight changes at 1000 mg/kg bw/day were reduced (38% to 89% of the control group value) on Days 1 to 8, 8 to 15, 43 to 50, 50 to 57, 57 to 64, and 71 to 78, and were significantly reduced (p ≤ 0.05) on Days 1 to 8, 50 to 57, and 71 to 78. During the overall study period (Days 1 to 90), mean body weight change at 1000 mg/kg bw/day was 88% of the control group value but this reduction was not statistically significant. Similarly, a slight reduction in mean body weight (93% of the control group value) was observed on Day 90 at 1000 mg/kg bw/day, although this reduction did not achieve statistical significance. Mean body weight changes at 300 mg/kg bw/day were considered not to be toxicologically relevant.

Female rats

Mean body weights and body weight gains were unaffected by administration of the test substance at dose levels as high as 1000 mg/kg bw/day.

FOOD CONSUMPTION

Male rats

Mean absolute (g/day) and relative (g/kg bw/day) food consumption values were unaffected by administration of the test substance at dose levels as high as 300 mg/kg bw/day. Mean absolute and relative food consumption values were significantly reduced (p ≤ 0.05) at 1000 mg/kg bw/day on Days 8 to 15 (87% and 92% of the respective control group values). These transient reductions did not affect food consumption values during the overall study period (Days 1 to 90) at 1000 mg/kg bw/day. Food consumption values were generally comparable among the 4 dose groups during all other
intervals and did not significantly differ.

Female rats

Mean absolute and relative food consumption values were unaffected by administration of the test substance at dose levels as high as 300 mg/kg bw/day. Mean absolute and relative food consumption values were significantly reduced (p ≤ 0.05) at 1000 mg/kg bw/day on Days 1 to 8 (90% and 91% of the respective control group values). These transient reductions did not affect food consumption values during the overall study period (Days 1 to 90) in the 1000 mg/kg bw/day dose group. Mean absolute food consumption values were significantly increased (p ≤ 0.05) on Days 71 to 78 and 78 to 85 at 300 mg/kg bw/day. These increases did not occur in a dose-dependent manner and were not attributed to administration of the test substance.Food consumption values were generally comparable among the 4 dose groups during all other intervals and did not significantly differ.

OPHTHALMOSCOPIC EXAMINATION

Male and female rats

Administration of the test substance at dose levels as high as 1000 mg/kg bw/day did not result in any ophthalmic changes that could be attributed to the test substance.

ESTROUS CYCLING

Administration of the test substance at dose levels as high as 1000 mg/kg bw/day did not result in any significant or biologically important differences in either the mean number of estrous stages per 29 or 30 days or in the number of rats with 6 or more consecutive days of diestrus.

NEUROBEHAVIOUR
Functional observation battery incl. assessment of grip strength

Male rats

Administration of the test substance at dose levels as high as 1000 mg/kg bw/day did not result in any differences in functional observation battery (FOB) assessments that could be attributed to the test substance.

Female rats

Administration of the test substance at dose levels as high as 300 mg/kg bw/day did not result in any differences in FOB assessments that could be attributed to the test substance. A significant increase (p ≤ 0.01) in the mean score for appearance (unkempt appearance and urine and/or fecal staining) occurred at 1000 mg/kg bw/day, correlating with the clinical observations recorded for this group. There were no other statistically significant or biologically important differences among the 4 dose groups.

MOTOR ACTIVITY

Male and female rats

Administration of the test substance at dose levels as high as 1000 mg/kg bw/day did not result in any significant or biologically important differences in either the total number of movements or the total time spent in movement in the motor activity assessments that could be attributed to the test substance.

CLINICAL PATHOLOGY

HEMATOLOGY AND COAGULATION

Male rats

Hematocrit, mean corpuscular hemoglobin (MCH), and mean corpuscular volume (MCV) were slightly, but significantly reduced (p≤ 0.05), and reticulocytes and platelets were significantly increased (p≤ 0.05) at 1000 mg/kg bw/day on Day 91. Significant reductions (p≤ 0.05) in hemoglobin were observed on Day 91 in each of the groups. These hemoglobin values represented 95% to 97% of the control group value. Only the reduction at 1000 mg/kg bw/day was considered compound-related, as significant reductions and increases in other hematologic parameters correlated with this reduction at this dose level.

Female rats

Mean corpuscular hemoglobin concentration (MCHC) was statistically significantly decreased at 1000 mg/kg bw/day. Mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV) were statistically significantly reduced (p ≤ 0.05) in the 300 and 1000 mg/kg bw/day groups on Day 91. However, there was no dose dependency, and the changes were not accompanied by altered hemoglobin or hematocrit values. Reticulocytes, leukocytes, and lymphocytes were statistically significantly increased (p ≤ 0.05) at 1000 mg/kg bw/day on Day 91.

CLINICAL CHEMISTRY

Male rats

Total bilirubin was significantly increased (p ≤ 0.05) and triglyceride and glucose were significantly reduced (p ≤ 0.05) at 1000 mg/kg bw/day on Day 91. Other parameters tested were not significantly altered.

Female rats

Total bilirubin, cholesterol, and phosphorus were significantly increased (p ≤ 0.05) at 1000 mg/kg bw/day on Day 91.

No other test substance related effects were observed in males and females.

URINALYSIS

Female rats

Large amounts of bilirubin were present in samples obtained from approximately half of the female rats in each of the groups administered the test substance. The presence of bilirubin in samples from approximately half of the female rats in each of these groups, was statistically significant (p ≤ 0.01). The presence of bilirubin in samples obtained from the treated groups was attributed to administration of the test substance. Only 3 samples obtained from female rats in the 100 mg/kg bw/day had epithelial cells present during microscopic examination of sediment. The remaining 6 samples had no epithelial cells present. Both the presence and the absence of epithelial cells in samples obtained at 100 mg/kg bw/day were significantly different (p≤ 0.01) from the respective control group values. However, these differences did not occur in a dose dependent manner and were therefore not attributed to administration of the test substance.

GROSS PATHOLOGY

Male and female rats

Administration of the test substance at dose levels as high as 1000 mg/kg bw/day did not result in any gross lesions that could be attributed to the test substance. All gross lesions were considered incidental, of the nature commonly observed in this strain and age of rat, and/or were of similar incidence in control and treated animals.

ORGAN WEIGHTS

Male rats

Increases or significant increases (p ≤ 0.05 or p ≤ 0.01) in the absolute weight of the liver, as well as the ratio of the liver to terminal body weight and to brain weight, occurred in the 300 and 1000 mg/kg bw/day groups. The increase at 1000 mg/kg bw/day (> 10% vs controls) correlated with the microscopic finding of centrilobular hypertrophy .
Statistical differences from the respective controls were observed in isolated organ weight values. These organ weight differences were not considered toxicologically relevant because: 1) the weight differences were never significant by all 3 means of comparison (i.e., as the absolute weight, as a % of terminal body weight, and as a % of brain weight); 2) the differences lacked a dose relationship; and 3) microscopic changes were not associated with these weight changes at 1000 mg/kg bw/day.

Female Rats

Administration of the test substance at dose levels as high as 100 mg/kg bw/day did not result in any statistically significant or biologically important differences in organ weight values that could be attributed to the test substance. Significant increases (p ≤ 0.01) in the absolute weight of the liver, as well as the ratio of the liver to terminal body weight and liver to brain weight, occurred in the 300 and 1000 mg/kg bw/day groups (>10% vs controls). The increase at 1000 mg/kg bw/day correlated with the microscopic finding of minimal centrilobular hypertrophy.
Other changes in organ weight ratios were noted in the 100 and 300 mg/kg bw/day groups with no supporting dose-dependent trends and no microscopic correlations. No other organ weight changes were attributed to the administration of the test substance. Isolated organ weight values were statistically different from their respective controls. There were, however, no patterns, trends, or correlating data to suggest these values were toxicologically relevant. Thus, all other organ weight differences observed were considered incidental and/or related to differences in sexual maturity and were considered unrelated to administration of the test substance.

HISTOPATHOLOGY

Male and female rats

Administration of the test substance at dose levels as high as 300 mg/kg bw/day did not result in any microscopic lesions that could be attributed to the test substance. Microscopic examination revealed minimal centrilobular hypertrophy in the livers of male and female rats assigned to the 1000 mg/kg bw/day group.

MALE FERTILITY PARAMETERS

Sperm Motility, Count, Density, and Spermatid Count

Administration of the test substance at dose levels as high as 1000 mg/kg bw/day did not result in any effects on sperm motility as assessed via a sample obtained from the vas deferens or sperm count as assessed via a sample obtained from the cauda epididymis. No effects on testicular spermatid count or density were apparent at dose levels as high as 300 mg/kg bw/day. Slightly lower testicular spermatid count and related spermatid density were observed in the 1000 mg/kg bw/day group (81% and 74% of the respective control group values) without reaching statistical significance. These differences were not considered adverse because there were no corresponding reductions in absolute testicular weights and no microscopic correlations in testicular histology.

Sperm Morphology

Administration of the test substance at dose levels as high as 1000 mg/kg bw/day did not result in any effects on sperm morphology as assessed via a sample obtained from the cauda epididymis.


Effect levels

Dose descriptor:
NOAEL
Effect level:
300 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Clinical signs, body weight; food consumption, clinical pathology

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

All dose formulations used in this study were formulated appropriately and remained within the concentration acceptance criteria (i.e. difference between analytically determined mean concentration and nominal concentration < 15 %). Homogeneity testing showed that the formulation technique used produced homogenous dose formulations.

Data from the 14 -days dose range finding study (99C0284/11X221)

In this study, there were no incidences of mortality and no toxicologically relevant test item related changes in hematology, clinical chemistry and urinalysis parameters in either the male or the female rats. Except for the liver, no relevant test item-related changes in organ weights were noted on the day of scheduled necropsy. Macroscopical and histopathological examinations revealed no adverse test item related gross lesions or microscopic findings in both male and female rats.

Treatment of male rats with the test item resulted in adverse clinical signs (discoloured fur, mild to moderate dehydration, mild to moderate excess salivation, hunched posture, rales, decreased motor activity, swelling in the axillary region and ptosis), reductions in body weight gain and food consumption, and increases in liver weights at the high dose level of 1000 mg/kg bw/day (Table 5.5-1). Females at the same dose level showed adverse clinical signs (discoloured fur, mild dehydration, urine-stained abdominal fur and chromorhinorrhea) and increased liver weights. Increases in liver weights were also seen in females treated at 300 mg/kg bw/day.

In the absence of concomitant macroscopical and histopathological findings, the increased liver weights noted in both sexes at 1000 mg/kg bw/day and in females also at 300 mg/kg bw/day were not considered to represent adverse effects.

Applicant's summary and conclusion