Registration Dossier

Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1985-04-30 to 1985-05-28
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Guideline study (OECD 407), according to GLP. Three deficiencies to current guidelines: 1. Wet weighing of organs was limited to brain, liver, spleen, kidneys, adrenals and gonads 2. Histopathology was limited to spleen, heart, liver, kidney and adrenal gland 3. No FOB (a subchronic study is not available)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1986
Report Date:
1986

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity in Rodents)
Version / remarks:
adopted on may 12, 1981
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: solid
- Analytical purity: commercial grade
- Test item storage conditions: room temperature

Test animals

Species:
rat
Strain:
other: F3-hybrid of R II 1/Tif x R II 2/ Tif
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Animal Production CIBA-GEIGY LTD., 4332 Stein / Switzerland
- Age at study initiation: approximately 4-5 weeks at delivery
- Weight at study initiation: males: 101-114 g, females: 97-122 g, at the first weighing session during the acclimatization period (day -5).
- Fasting period before study: no
- Housing: Specified pathogen free (SPF) standard laboratory conditions, housed in groups of 5 in Macrolon cages type 4 with standardized granulated soft wood bedding (Societe Parisienne des Sciures Pantin).
- Diet: Pelleted, certified standard diet Nafag No. 890 Tox, ad libitum (except for a 20-hour fasting period prior to blood sampling). All batches of diet were assayed for composition and contaminant levels by the manufacturer. Analytical results were deposited at the animal supply office (CIBA-GEIGY LTD., Pharmaceuticals Division PH 2 . 1 6 2 ).
- Water: Tap water ad libitum.
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22±2 °C
- Humidity: 55+10%
- Air changes: 16-20 air-changes per hour
- Photoperiod: 12 hours light per day

IN-LIFE DATES: From: 1985-04-30 To: 1985-05-28

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: Distilled water containing 0.5% carboxymethylcellulose and 0.1% Tween 80
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 0, 40, 200 and 1000 mg/kg bw/ day in distilled water containing 0.5% carboxymethylcellulose and 0.1% Tween 80 (prepared by Pharmaceuticals Division, Ciba-Geigy Ltd).
- Amount of vehicle (if gavage): 10 mL/kg bw / day

The test item was administered daily by oral gavage for 4 weeks. Administered quantities were adjusted daily to individual animal body weight. For blood chemistry measurements, feed was withheld for about 20 hours prior to blood removal.
Analytical verification of doses or concentrations:
no
Details on analytical verification of doses or concentrations:
Only stability tests of test item in vehicle were performed. Prior to the start of the study, a stability analysis of the test item in the selected vehicle, at appropriate concentrations, was requested by the analytical laboratories of CIBA-GEIGY Ltd, Basel/Switzerland. The results of this analysis (S-9/85) are filed in the archives of Experimental Toxicology, CIBA-GEIGY Ltd, Stein / Switzerland. According to these, no significant change of concentration of the test article in the vehicle could be observed over a 4-hour period.
Duration of treatment / exposure:
28 days
Frequency of treatment:
daily (7 days/week)
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 40, 200 and 1000 mg/kg bw / day
Basis:
actual ingested
No. of animals per sex per dose:
five males and five females per dose
Control animals:
yes, concurrent vehicle
Positive control:
no

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily, recorded weekly

DETAILED CLINICAL OBSERVATIONS: No

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION:
- Mean weekly diet consumption calculated as g food/kg body weight/week: Yes, per cage group

WATER CONSUMPTION: Yes
- Time schedule for examinations: weekly, per group

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: prior to treatment (day -6) and towards the end (day 24) of the treatment
- Dose groups that were examined: High dose group and vehicle control group

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at the end of the in life phase, between the hours of 07:00 and 0900 a.m.
- Anaesthetic used for blood collection: Yes (Ether)
- Animals fasted: Yes
- How many animals: 40 (all animals)
- Parameters checked: Erythrocyte Count, Hemoglobin, Hematocrit, Mean corpuscular volume, Mean corpuscular hemoglobin, Mean corpuscular hemoglobin concentration, Leucocyte Count, Differential Leucocyte Count, Thrombocyte Count

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at the end of the in life phase, between the hours of 07:00 and 0900 a.m.
- Anaesthetic used for blood collection: Yes (Ether)
- Animals fasted: Yes
- How many animals: 40 (all animals)
- Parameters checked: Glucose, Urea, Total protein, Albumin, Globulins, A/G Ratio, Aspartate aminotransferase, Alanine aminotransferase, Alkaline phosphatase,

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Hearing test only
Animals of the highest dosage group and of the control group were examined prior to treatment (day -6) and towards the end (day 24) of the treatment. Auditory perception was assessed by reflex reaction to standard sound emission.
Sacrifice and pathology:
GROSS PATHOLOGY: Yes (Wet weighing of organs was limited to brain, liver, spleen, kidneys, adrenals and gonads)
HISTOPATHOLOGY: Yes (Limited to spleen, heart, liver, kidney and adrenal gland)

Statistics:
Not fully identified:
- univariate analysis (Y. Lepage, Biometrika (1971) 58: pp. 213-217),
- trend test (H. R. Jonckheere, Biometrika (1954) 41: pp. 133-14)

Results and discussion

Results of examinations

Details on results:
CLINICAL SIGNS AND MORTALITY
No death occurred during the experiment. No clinical symptoms and no signs of systemic toxicity were observed.

BODY WEIGHT AND WEIGHT GAIN
The mean body weight values in all male and female treatment groups were similar to that of the respective controls during the whole experiment.

FOOD CONSUMPTION
The mean feed consumption values in all male and female treatment groups were similar to that of the respective controls during the whole experiment.

FOOD EFFICIENCY
The mean feed conversion values in all male and female treatment groups were similar to the values of the respective controls during the whole experiment.

WATER CONSUMPTION
Within the limits of reliability of the measuring method, the mean water consumption values in all male and female treatment groups were considered to be within a normal range, and comparable to the values of the control group.

OPHTHALMOSCOPIC EXAMINATION AND HEARING TEST
Ophthalmic inspections and hearing examinations performed before and towards the end of the administration period revealed no evidence of a reaction to the treatment.

HAEMATOLOGY
A minor increase in the percentage of segmented neutrophils was found in males and females of the high dosage group (1000 mg/kg bw per day), but the difference to controls was not reaching a level of statistical significance. No other changes attributable to the administration of the test item were seen throughout the treatment groups.

CLINICAL CHEMISTRY
The findings in blood chemistry investigations generally were unremarkable. Besides a minor (statistically not significant) increase in aspartate aminotransferase activity in the male group 4, treated with 1000 mg/kg bw per day, no changes attributable to the treatment with the test item were found.

ORGAN WEIGHTS
A trend to absolute and relative mean liver weight increase was observed in males, and an opposite trend to liver weight decrease was seen in females. Since there were no substantial differences in the histopathological appearance of this organ between control and treated animals, and since no systematic pattern emerged, which indicated a treatment-related effect, no experimental relevance was attributed to this fluctuation.

GROSS PATHOLOGY
Macroscopical examination at autopsy revealed no evidence of a reaction to the treatment.

HISTOPATHOLOGY: NON-NEOPLASTIC
All microscopical changes noted in some control and treated animals were only incidental in nature and unrelated to the treatment with the test item.

Effect levels

open allclose all
Dose descriptor:
NOEL
Effect level:
200 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Only minor, statistically not significant changes in two isolated parameters (haematology / clinical chemistry) at high dose (1000 mg / kg bw / day)
Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Only minor, statistically not significant changes in two isolated parameters (haematology / clinical chemistry) at high dose (1000 mg / kg bw / day)

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
It can be inferred from the observations made during the above study that a "no observable effect level" for the test substance when administered by gavage over a period of 28 days is 200 mg/kg body weight and the NOAEL is 1000 mg/kg.
Executive summary:

In a 28-day subchronic toxicity study according to OECD guideline 407, five male and five female rats were treated with the test substance by gavage at dose levels of 40, 200 and 1000 mg/kg body weight. A control group received the vehicle (distilled water containing 0.5% carboxymethyl cellulose and 0.1% Tween 80) alone. The observed parameters were the following: Clinical signs, mortality, hearing test and ophthalmologic examinations, body weight, food and water uptake, hematology, clinical chemistry, gross pathology, organ weights (limited to brain, liver, spleen, kidneys, adrenals, gonads) and histopathology (limited to spleen, heart, liver, kidney and adrenal glands). No deaths occurred during the study and no clinical symptoms or signs of systemic toxicity were observed. Eye examination and hearing test, body weight gain and food consumption revealed no changes when compared to controls. A minor increase in the percentage of segmented neutrophils was found in males and females of the high dose group (1000 mg/kg bw), but the difference to controls was not reaching a level of statistical significance. In addition, a minor (statistically not significant) increase in aspartate aminotransferase activity in males treated with 1000 mg/kg bw was observed. The analysis of organ weights and organ weights ratios revealed no consistent treatment related effect. Trends to a dose-dependent liver weight increase in males and, inversely, liver weight decrease in females, were considered to be of no experimental relevance. No treatment related findings were recorded during macroscopical and histopathological investigations. Therefore, based on the presented results and under the conditions employed, the NOAEL for the test article when administered by gavage over a period of 28 days was set at 1000 mg/kg.