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Description of key information

Based on the results of a 28-day repeated dose toxicity study performed according to OECD guideline 407 and GLP principles, a NOEL of 1000 mg/kg bw/ day is established for Y-513 based on no effects seen at the highest dose level of 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:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
10.08.2007 - 30.10.2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study was performed according to the internationally recognized guidelines and according to GLP principles.
Qualifier:
according to
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity in Rodents)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))
Deviations:
no
Qualifier:
according to
Guideline:
other: 28-day repeated dose toxicity study in mammalian species prescribed in 'Concerning testing methods relating to the new chemical substances' (No 1121002, Pharmaceutical and Food Safety Bureau, MHLW
Deviations:
no
GLP compliance:
yes
Limit test:
no
Species:
rat
Strain:
other: Crl: CD(SD)
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River, Japan
- Age at study initiation: 5 weeks
- Weight at study initiation: 147.4 - 167.9g (males); 121.9 - 144.1g (females)
- Housing: stainless steel hanger cages with wire-mesh floor, individually housed
- Diet: MF pellet diet, ad libitum
- Water: dechlorinated tap water, ad libitum
- Acclimation period: 10 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.4 - 24.0
- Humidity (%): 48.1 - 63.0
- Air changes (per hr): 10 - 15
- Photoperiod (hrs dark / hrs light): 12/12
Route of administration:
oral: gavage
Vehicle:
other: Gum arabic in water (5.0 w/v%)
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:
The test substance and gum arabic were weighted accurately (the final concentration of gum arabic in the formulation was 5.0 w/v%) and suspended in purified water into a mortar to make 10.0 w/v% formulation. The lower concentrations of 2.5 and 0.5 w/v% suspensions were diluted from 10.0 w/v% formulation.

- Rate of preparation of dosing solution (frequency): Once per 7 days
- Storage temperature of dosing solution: stored in the dark and cold place


VEHICLE
- Justification for use and choice of vehicle (if other than water): the vehicle was chosen in a 14-day pilot study
- Concentration in vehicle: 0, 0.5, 2.5 and 10%
- Amount of vehicle (if gavage): 10 mL/ kg bw
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
The homogeneity and stability analyses were performed. The formulations were stable for 9 days and showed good homogeneity.
Analytical verification of test substance in the formulations was done by HPLC. The relative values to the setting values of all the formulations were in the range 100 +/- 10%.
Duration of treatment / exposure:
28 days
Frequency of treatment:
daily
Remarks:
Doses / Concentrations:
0, 50, 250, 1000 mg/kg bw/ day
Basis:
actual ingested
No. of animals per sex per dose:
5
Control animals:
yes
Details on study design:
- Dose selection rationale:
A 14-days oral repeated dose toxicity study was performed with exposure at 25, 250, 500 and 1000 mg/kg bw/ day. Based on absence of adverse effects in the animals (males and females), the highest dose was chosen at 1000 mg/kg bw/ day.
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: 3 times per day

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: day 1, 3, 8, 12, 17, 21, 26, 28 exposure period and day 1, 5, 10, 14 recovery period

FOOD CONSUMPTION:
- Time schedule for examinations: days 1,3, 8, 15, 22, 28 dosing period; days 4, 8, 14 recovery period

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the completion of dosing period and of the recovery period
- Anaesthetic used for blood collection: Yes (ether)
- Animals fasted: Yes
- How many animals: All animals
- Parameters examined:
Red blood cell count
White blood cell count
Hemoglobin
Hematocrit value
Mean corpuscular volume
Mean corpuscular hemoglobin
Mean corpuscular hemoglobin concentration
Platelet count
Reticulocyte count
Prothrombin time
Activate partial thromboplastin time
Differentiation of leukocytes

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at sacrifice
- Animals fasted: Yes
- How many animals: All animals
- Parameters examined:
Asparate aminotransferase
Alanine aminotransferase
Alkaline phosphatase
Cholinesterase
y-Glutamyl transpeptidase
Total cholesterol
Trigliceryde
Glucose
Total protein
Albumin
a/g ratio
Blood urea nitrogen
Creatinine
Total bilirubin
Calcium
Inorganic phosphorus
Sodium
Potassium
Chloride

URINALYSIS: Yes
- Time schedule for collection of urine: at the completion of dosing period
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- How many animals: all animals
- Parameters examined:
Urine volume
Color
Turbidity
Specific gravity
pH
Protein
Glucose
Occult blood
Urinary sediments (conducted for Control and 1000 mg/kg bw/ day groups)

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: week 4
- Dose groups that were examined: all animals
- Battery of functions tested: reflex test, grip strength and motor activity
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
Gross necropsy incl body surfaces, all orifices, subcutaneous tissue, cranial, thoracic, abdominal and pelvic cavities;
Organ weights: liver, heart, kidneys, testes, epididymides, ovaries, brain, spleen, thymus, adrenals.

HISTOPATHOLOGY: Yes
Trachea, lungs, stomach, intestines, liver, heart, kidneys, urinary bladder, testes, epididymides, prostate, seminal vesicles, ovaries, uterus, vagina, brain, spinal cord, sciatic nerve, bone marrow, axillary and mesentreic lymph nodes, spleen, thymus, pituitary glands, thyroid, adrenals, eye balls
Other examinations:
14 days recovery groups were additionally included (0 and 1000 mg/kg bw)
Statistics:
Data regarding body weights (excluding those at the time of necropsy), food intake, items of hematological examinations, items of blood chemical examinations, urine volume and specific gravity, organ weights, grip strength and locomotor activity count were analyzed using the Bartlett's test for homogeneity of variance. If the variances were homogeneous at a significance level of 5%, the difference between the vehicle control group and each of the treatment groups was analyzed by the Dunnett's test.
If the variances were not homogeneous, the difference between the vehicle control group and each of the treatment group was analyzed by the nonparametric Dunnett's test.
For defecation (number of feces) and urination (number of urine pools), the difference between the vehicle control group and each of the treatment groups was analyzed by the nonparametric Dunnett's test.
Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY
No mortality occurred in males or females.

Yellow stool was observed in both sexes of the 250 mg/kg bw/day or more. This was not observed 3 days after termination of dosing period in both sexes of the 1000 mg/kg bw/day recovery group.
In the vehicle control group, loss of hair and scab formation of the neck in one male were observed as accidental changes.

No abnormalities attributable to the test substance were observed in males. The number of urinations was significantly increased in one female of the 1000 mg/kg bw/day in week 1 of the dosing period.

BODY WEIGHT AND WEIGHT GAIN
No abnormalities observed in males or females.

FOOD CONSUMPTION
No abnormalities observed in males or females.

HAEMATOLOGY
No abnormalities attributed to the test substance were observed in males or females.
Hemoglobin concentration was significantly increased in males of the 50 mg/kg bw/day at termination of the dosing period. Ratios of neutrophiles and lymphocytes were increased statistically in male of the 1000 mg/kg b.w. at termination of recovery period. There changes were not considered of toxicological significance since they were in the range of historical data of the laboratory.

CLINICAL CHEMISTRY
No abnormalities attributed to the test substance were observed in males or females. Calcium concentration was significantly inreased in males of the 50 mg/kg bw/day, chloride was decreased in males of the 50 mg/kg bw/ day and 250 mg/kg bw/ day at termination of the dosing period. Potassium was increased significantly in males of the 1000 mg/kg bw/day group at termination of the recovery period. There changes were not considered of toxicological significance since they were in the range of historical data of the laboratory.

URINALYSIS
No abnormalities attributed to the test substance were observed in males or females.
Specific gravity was decreased significantly in female of the 1000 mg/kg bw/day group. These changes were not considered of toxicological significance since they were in the range of historical data of the laboratory.

NEUROBEHAVIOUR
No abnormalities were noted in males or females.
Locomotor activities were significantly increased in the measure periods of 40-50 min, 50-60 min and total measurement time 0-60 minutes in the female of 250 mg/kg bw/day, but these changes were not considered to be of toxicological significance.


ORGAN WEIGHTS
No abnormalities were observed in males or females.
Incease in absolute and relative thymus weights was measured in females of the 50 mg/kg bw/day group (increases of appr. 49% and 43% for resp. absolute and relative weight ). In absence of a dose-relationship of this effect, this change was not considered of toxicological significance. Increase in absolute and relative epididymides weight in males of the 1000 mg/kg bw/day was seen after the recovery period (increase of appr. 6% and 12% for absolute and relative weight resp.). These changes were not considered of toxicological significance since they were in range of historical data of the laboratory.

GROSS PATHOLOGY
No substance-related abnormalities were observed in males or females.

HISTOPATHOLOGY
No substance-abnormalities were observed in males or females.
Dose descriptor:
NOEL
Effect level:
1 000 mg/kg bw/day (actual dose received)
Sex:
male/female
Basis for effect level:
other: No effects seen at highest dose (1000 mg/kg bw/day).
Critical effects observed:
not specified
Conclusions:
Based on the results of a 28-day repeated dose toxicity study performed according to OECD guideline 407 and GLP principles, a NOEL of 1000 mg/kg bw/ day is established for Y-513 based on no effects seen at the highest dose level of 1000 mg/kg bw/ day.
Executive summary:

A 28-day repeated dose toxicity study was performed according to OECD guideline 407 and GLP principles. Test substance Y-513 was administered by gavage to male and female rats at 0, 50, 250 or 1000 mg/kg bw/day for 28 days. The study included groups for which the exposure period was followed by a 14-day recovery period (0 and 1000 mg/kg bw/ day). No substance related clinical signs were noted, no changes in body weight gain occurred. No abnormalities were noted in sensorimotor functions, food intake, hematological examinations, blood chemistry, urinalyses or pathological examinations. No differences were observed between the exposed and unexposed groups in the recovery period. Based on the absence of effects, the NOEL of Y-513 in rats for daily exposure during 28 days was established at 1000 mg/kg bw/day.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
Study was performed according to the internationally recognized guidelines and according to GLP principles.

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 28-day repeated dose toxicity study was performed according to OECD guideline 407 and GLP principles. Test substance Y-513 was administered by gavage to male and female rats at 0, 50, 250 or 1000 mg/kg bw/day for 28 days. The study included groups for which the exposure period was followed by a 14-day recovery period (0 and 1000 mg/kg bw/ day). No substance related clinical signs were noted, no changes in body weight gain occurred. No abnormalities were noted in sensorimotor functions, food intake, hematological examinations, blood chemistry, urinalyses or pathological examinations. No differences were observed between the exposed and unexposed groups in the recovery period. Based on the absence of effects, the NOEL of Y-513 in rats for daily exposure during 28 days was determined to be 1000 mg/kg bw/day.


Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
One reliable study available.

Justification for classification or non-classification

Based on the available repeated dose data, Y-513 is not classified for effects after repeated exposure according to Regulation (EC) 1272/2008.