Registration Dossier

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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report date:
2000

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)
Version / remarks:
OECD 407 (1995) Japanese Guidelines on Industrial Chemicals (1986)
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Constituent 1
Reference substance name:
T-7145
IUPAC Name:
T-7145
Details on test material:
- Name of test material (as cited in study report: 2-trifluoromethyl-3-ethoxy-dodecafluorohexane
- Physical state: liquid
- Analytical purity: 99.89%
- Impurities (identity and concentrations): 0.11% unidentified
- Stability under test conditions: Stable
- Storage condition of test material: room temperature in air-tight container

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Japan, Inc.
- Weight at study initiation: 181-200 g (males); 132-157 g (femailes)
- Housing:
polycarbonate cages (265W X 426D X 200H ram, Tokiwa
Kagaku Kikai Co., Ltd.) with hard wood chip bedding (Beta chip, Charles River Japan, Inc.).


Pellet diet for experimental animals (MF, Oriental Yeast Co., Ltd.)
- Water:
ad libitum
- Acclimation period:
5 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22+/- 2 deg
- Humidity (%): 55+/- 15%
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): (12hrs/12hrs)

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
CMC (carboxymethyl cellulose)
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:

The test substance was emulsified in a 0.5% CMC-Na aqueous solution mixed with 0.1% Tween 80 (CMC-Na: Kanto Chemical Co., Inc., Lot No. 007G1487, Tween 80: Tokyo Kasei Kogyo Co., Ltd., Lot No. GH01). The dosing solutions were prepared once a week, and were stored in a dark refrigerated place. They were used within 8 days. The dosing solutions were treated with ultrasonicator for 10 minutes at the time of use and then were continuously stirred until administration.

The homogeneity and stability of the test substance in the dosing solution for 8 days stored in a dark refrigerated place were confm'ned within the range of 13 to 340 mg/mL before the first administration (Annex 1). The dosing solutions for each dose group prepared at the first time were analyzed and confirmed that the concentrations of the test substance were within
each concentration +10%

- Justification for use and choice of vehicle (if other than water):
A stable suspension was formed in CMC
- Concentration in vehicle: 0, 13.4, 66.7, 333.4 mg/mL
- Amount of vehicle (if gavage): 3 mL/kg
Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
The homogenecity and stability of the test substance in the dosing solution for 8 days stored in a dark refrigerated place were confm'ned within the range of 13 to 340 mg/mL before the first administration (Annex 1). The dosing solutions for each dose group prepared at the first time were analyzed and confirmed that the concentrations of the test substance were within
each concentration +10%
Duration of treatment / exposure:
Test duration: 28 days
Frequency of treatment:
Daily
Doses / concentrations
Remarks:
Doses / Concentrations:

Basis:
other: Oral gavage
No. of animals per sex per dose:
5
Control animals:
yes
Details on study design:
- Dose selection rationale:

Preliminary dose-finding studies were performed. A single dose toxicity study (the test substance was administered to three non-fasted rats of both sexes at dose levels of 100, 500,
and 1000 mg/kg, respectively) revealed no toxic change in the clinical sign for 4 days, body weight, or necropsy. A 14-day repeated dose toxicity study (the test substance was administered to three rats of both sexes at dose levels of 0, 100, 500, and 1000 mg/kg,
respectively) revealed no toxic change considered to be related to the administration of T-7145 in the clinical sign, body weight, hematology, or necropsy. According to these results, the
highest dose level was set at 1000 mg/kg; this is the upper limit as prescribed in the guidelines. Dose levels were 40, 200 and 1000 mg/kg.

- Rationale for selecting satellite groups: High dose satellite group only to document reversibility of any effects.
- Post-exposure recovery period in satellite groups: 14-days
Positive control:
None

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily for 4 weeks


DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Twice/day during treatment. Once per day on every other day in the morning

BODY WEIGHT: Yes
- All rats were weighed once a week and the day before necropsy

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Yes; once/week

FOOD EFFICIENCY:
- No data

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
Hematology was performed on Day 29 and 43 at the scheduled sacrifice.
- How many animals: 5/sex/dose level
-See report for tables

CLINICAL CHEMISTRY: Yes


URINALYSIS: Yes
- Parameters checked in table: Yes, see report

NEUROBEHAVIOURAL EXAMINATION: Yes
Detailed clinical observations were made in all animals once before the first administration (the day before first administration) and once a week (Days 5, 12, 19, and 28) in the afternoon during the treatment period.
Sacrifice and pathology:
GROSS PATHOLOGY: Yes (see table)
HISTOPATHOLOGY: Yes (see table)
Statistics:
The numerical data were analyzed by multiple comparison tests. They were first analyzed by Bartlett's test. If the group variance was determined to be homogeneous, all groups were compared by a one-way analysis of variance. If Bartlett's test indicated heterogeneous variance, the Kruskal-Wallis test was employed, and a Dunnett's test or Durmett type multiple comparison was used when there was a significant difference between the groups. The
categorical data were analyzed by R x C Chi-square test, and when there was significance, Armitage's Chi-square test was used to compare the difference between the control group and
each treatment group. Statistical analysis was performed on items listed below. The analysis was not performed on clinical signs, functional observations (detailed clinical observations, sensory reactivity to stimuli), necropsy, or histological findings.

Multiple comparison test:
Body weight, functional observations (forelimb grip strength, hindlimb grip strength, and motor activity), food consumption,

Chi-square test: urinalysis (pH, protein, glucose, ketone bodies, bilirubin, occult blood, and urobilinogen)

Results and discussion

Results of examinations

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:
no effects observed
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
not specified
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:
effects observed, treatment-related
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY: No changes either sex

BODY WEIGHT AND WEIGHT GAIN: No changes either sex

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): No changes either sex

FOOD EFFICIENCY: No changes either sex

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No changes either sex

OPHTHALMOSCOPIC EXAMINATION: no data

HAEMATOLOGY: No changes either sex

CLINICAL CHEMISTRY: No changes either sex

URINALYSIS: No changes either sex

NEUROBEHAVIOUR: No changes either sex

ORGAN WEIGHTS: At the end of the treatment period, a decreased absolute spleen weight was observed in
males of all treatment groups and a decreased relative weight of the spleen was observed in males of the 40 and 1000 mg/kg groups. These changes were not observed at the end of the
recovery period. Although decreased absolute and relative weights of the ovaries were observed in the 200 mg/kg group at the end of the treatment period, it was considered that these changes were not related to the administration of the test substance, because these changes were not observed in the 1000 mg/kg group. Decreased absolute and relative weights of the adrenals were observed in females of the 1000 mg/kg group and an increased relative weight of the epididymides was observed in the 200 mg/kg group at the end of the recovery period; however, it was considered
that these changes were not related to the administration of the test substance, because they were slight changes and not observed at the end of the treatment period.

GROSS PATHOLOGY: No changes either sex

HISTOPATHOLOGY: NON-NEOPLASTIC: Centrilobular acidophilic change of the hepatocytes in the liver of both sexes at 1000 mg/kg.

Effect levels

Key result
Dose descriptor:
NOAEL
Effect level:
ca. 1 000 mg/kg bw/day (actual dose received)
Based on:
act. ingr.
Sex:
male/female
Basis for effect level:
histopathology: non-neoplastic
organ weights and organ / body weight ratios
other: No changes attributable to the administration of the test substance were observed in the clinical sign, functional observations, body weight, food consumption, hematology, blood chemistry, urinalysis, organ weight, or necropsy.

Target system / organ toxicity

Key result
Critical effects observed:
no

Applicant's summary and conclusion

Conclusions:
Based on the results of the study, the No Observed Adverse Effect level of T-7145 is 1000 mg/kg/day.
Executive summary:

T-7145 was administered orally to male and female SD rats for 28 days at doses of 0, 40, 200, and 1000 mg/kg to investigate its toxicity and the reversibility. In the liver, centrilobular acidophilic change of the hepatocytes was found in both sexes of the 1000 mg/kg group in the histological examination. This change is known to be seen in the case of hypertrophy of the hepatocytes caused by induction of the drug metabolizing enzymes. Furthermore, hypertrophy of the hepatocytes is generally considered to be a result of the adaptive change.There is a possibility that acidophilic change of the hepatocytes observed in this study was also a result of the adaptive change as well as the case of hypertrophy of the hepatocytes. However, there was no change in the liver weight in this study. Good reversibility of this change was suggested, since it was not observed at the end of the recovery period. Although a decreased absolute spleen weight was observed in males of all treatment groups and a decreased relative weight of the spleen was observed in males of the 40 and 1000 mg/kg groups, these changes were considered unrelated to the administration of the test substance, because the absolute and relative weights of the spleen of control group were higher than those of background data and no histological changes were found in the spleen. These changes were not observed at the end of the recovery period. No changes attributable to the administration of the test substance were observed in the clinical sign, functional observations, body weight, food consumption, hematology, blood chemistry, urinalysis, organ weight, or necropsy.

Based on the results of the study, the No Observed Adverse Effect level of T-7145 is 1000 mg/kg/day.