1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007-11-30 to 2008-01-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: Japanese Guidelines for screening toxicity testing of chemicals: testing methods for new substances (1986)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one

EC Number:

263-731-6

EC Name:

1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one

Cas Number:

62780-89-6

Molecular formula:

C10H11ClN2O

IUPAC Name:

1-(3-chloropropyl)-1,3-dihydro-2H-benzimidazol-2-one

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material (as cited in study report): JNJ-119717-AAA (T001036)
- Physical state: solid

Specific details on test material used for the study:

- Analytical purity: 99.9%
- Purity test date: no data
- Lot/batch No.: A14JB3442
- Expiration date of the lot/batch: 2016-09-30 (retest date)
- Stability under storage conditions: until retest date
- Storage condition of test material: at room temperature
- Stability under test conditions: not indicated

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Strain: HanRcc: WIST (SPF) rats
- Source: RCC Ltd, Laboratory Animal Services, Wölferstrasse 4, 4414 Füllinsdorf, Switzerland
- Age at delivery: ca. 7 weeks
- Weight at acclimatization: Males: 170.8 g to 205.6 g (mean 188.0 g); Females: 131.7 g to 158.4 g (mean 146.7 g)
- Fasting period before study: no data
- Fasting period during the study: for approx. 18 hours before blood sampling after 4 weeks and after 6 weeks
- Housing: standard laboratory conditions; in groups of five in Makrolon type-4 cages with wire mesh tops and standard softwood bedding
- Diet (e.g. ad libitum): pelleted standard Kliba Nafag 3433 (batch n° 65/07) rat/mouse maintenance diet, ad libitum
- Water (e.g. ad libitum): community tap water from Itingen, ad libitum in water bottles
- Acclimation period: 7 days ; under test conditions after health examination. Only animals without any visible signs of illness were used

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3 °C
- Humidity (%): 30-70%
- Air changes (per hr): 10-15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12hr fluorescent light/12-hour dark cycle with music during the light period

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
The dose formulations were prepared weekly. T1036 was weighed into a glass beaker on a tared Mettles balance. A small amount of vehicle was added and after initial stirring, the remaining vehicle was added. The mixtures were stirred using a magnetic stirrer and stored at room temperature (15-25 °C). Homogeneity of the test item in the vehicle was maintained during the daily administration period using a magnetic stirrer.

VEHICLE
- Justification for use and choice of vehicle (if other than water): no data
- Concentration in vehicle: 0-6-20-60 mg/ml/day
- Amount of vehicle (if gavage):5 ml/kg body weight
- Lot/batch no. (if required): 18787208, 12786337
- Purity: not specified

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

STABILITY OF DOSE FORMULATIONS:
Stability of dose formulations for at least one week was based upon the results of stability analysis within RCC study n° B65114

ANALYSIS OF DOSE FORMULATIONS:
After experimental start, samples of the control group as well as three samples (top, middle and bottom) of about 2g of each concentration were taken prior to dosing for analysis of homogeneity and concentration and stability. Samples of about 2g of each concentration were taken during week 3 to confirm homogeneity and concentration.
The samples were delivered at ambient temperature to the analytical department and then stored at -20 +/- 5°C until analysis. The test item was used as analytical standard.
The test item concentrations were determined by HPLC coupled to an UV detector and quantified with the area under the peak. The identity of T1036 was confirmed by its retention time which was similar to that measured in the working standards. The test item content in all samples was found to be within the accepted range of +/- 20% of the nominal content. In addition, the test item formulations were found to be homogenously distributed in corn oil vehicle. The application formulations were considered to be stable for at least 2 hours and 7 days when kept under storage conditions. The results confirm the correct preparation and storage of application formulations during the conduct of the study.

Duration of treatment / exposure:

Duration of treatment period: 28 days
Duration of recovery period: 14 days

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Doses / concentrations 2

Dose / conc.:

30 mg/kg bw/day (nominal)

Doses / concentrations 3

Dose / conc.:

100 mg/kg bw/day (nominal)

Doses / concentrations 4

Dose / conc.:

300 mg/kg bw/day (nominal)

No. of animals per sex per dose:

0 and 300 mg/kg/day: 10 males and 10 females
30 and 100 mg/kg/day: 5 males and 5 females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Dose levels were selected based on a previous dose range finding study (RCC study n° B65114)
- Rationale for selecting satellite groups: no data
- Post-exposure recovery period in satellite groups: 14 days

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes, all animals
- Time schedule: Animals were observed for clinical signs once before commencement of administration, twice daily on days 1 to 3, and once daily during days 4 to 28 of treatment period ; daily during the days 1 to 14 of the recovery period

DETAILED CLINICAL OBSERVATIONS: Yes, all animals
- Time schedule: once before commencement of administration and once weekly (weeks 1 to 3) thereafter
- Observations made: animals were observed in their home cages, outside of teir home cages in a standard arena and in the hand.

BODY WEIGHT: Yes, all animals
- Time schedule for examinations: weekly during acclimatization, treatment and recovery periods and before necropsy
- Method of recording: using an on-line electronic recording system consisting of a Mettler balance connected to RCC computer

FOOD CONSUMPTION:
- Time schedule: once during the acclimatization period and weekly thereafter
- Method of recording: using an on-line electronic recording system consisting of a Mettler balance connected to RCC computer

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: after 4 weeks (all animals) , after 6 weeks (recovery animals only)
- Anaesthetic used for blood collection: Yes, light isoflurane anesthesia
- Animals fasted: Yes, for approx. 18 hours before blood sampling, in metabolism cages
- How many animals: all
- Parameters examined: erythrocyte count, hemoglobin, hematocrit, mean corpuscular volume, red cell volume distribution width, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, hemoglobin concentration distribution width, reticulocyte count, reticulocyte maturity index (low, medium, high fluorescence)total leukocyte count, differential leukocyte count: neutrophils, eosinophils, basophils, lymphocytes, monocytes, large unstained cells, platelet count, hemoglobin derivatives (methemoglobin, Heinz bodies), coagulation (prothrombin time, activated partial thromboplastin time)

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: after 4 weeks (all animals) , after 6 weeks (recovery animals only)
- Animals fasted: Yes, light isoflurane anesthesia
- How many animals: all
- Parameters examined: glucose, urea, creatinine, total bilirubin, total cholesterol, triglycerides, aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, glutamate dehydrogenase, alkaline phosphatase, gamma-glutamyl-transferase, creatine kinase, sodium, potassium, chloride, calcium, phosphorus, total protein, albumin, globulin, albumin/globulin ratio

URINALYSIS: Yes
- Time schedule for collection of urine: after 4 weeks (all animals) , after 6 weeks (recovery animals only)
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes, for approx. 18 hours before blood sampling
- Parameters examined: physical examination: urine volume (18 hrs), specific gravity (relative density), color, appearance; chemical examination: pH value, nitrite, protein, glucose, ketones, urobilinogen, bilirubin, erythrocytes, leukocytes

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: during week 4
- Dose groups that were examined: all
- Battery of functions tested: grip strength / motor activity
During week 4, relevant parameters from a modified irwin screen test were evaluated in all animals.
Grip strength: Forelimb and hind limb grip strength measurements were performed using a push-pull strain gause. The animals were placed with the forepaws inside a triangular grasping ring and with the hind paws outside a triangular grasping ring. Using one hand, the animals were held towards the base of the tail and steadily pulled away or towards the ring until the grip was broken. Each measurement was repeated three times. Means were calculated and recorded.
Locomotor activity: Locomotor (decreased or increased) activity was measured quantitatively with AMS Föhr Medical Instruments GmbH (FMI) and DeMeTec GmbH Acitivity Monitor System. Animals were monitored during the fourth treatment week for a 60-minute period and the total acitivity of the measuring period.

OTHER:
VIABILITY/MORTALITY: yes, all animals
- Time schedule for examinations: observations were recorded twice daily

ORGAN WEIGHT:
- Organs of which weight was determined: adrenal glands, brain, epididymides, heart, kidneys, liver, ovaries, spleen, testes, thymus
- Method: the organs were weighed before fixation and recorded on the scheduled dates of necropsy. relative organ weights were calculated on the basis of the body weight and brain weight. The terminal body weight was recorded immediately prior to necropsy and the organ to terminal body weight ratios as weel as organ to brain weight ratios were determined.

Sacrifice and pathology:

NECROPSY: all animals were weighed and necropsied. Descriptions of all macroscopical abnormalities were recorded. All animals were anesthetized by intraperitoneal injection of pentobarbitone and killed by exsanguination. Samples of tissues and organs were collected from all animals at necropsy and fixed in neutral phosphate buffered 4% formaldehyde solution except for eyes with optic nerve and Harderian gland which were fixed in Davidson's solution or epididymides and testes which were fiwed in Bouin's solution.

GROSS PATHOLOGY: Yes
- Tissues and organs examined: adrenal glands, aorta, bone (sternum, femur including joint), bone marrow (femur), brain (including section of medulla/pons, cerebral and cerebellar cortex), cecum, colon, duodenum, epididymides, esophagus, eyes with optic nerve, Harderian gland, heart includign auricles, ileum with Peyer's patches, jejunum with Peyer's patches, kidneys, larynx, lacrimal gland (exorbital), liver, lungs (filled with formalin at necropsy), lymph nodes (mesenteric and mandibular), mammary gand area, nasal cavity, ovaries, pancreas, pharynx, pituitary gland, prostrate gland including coagulating glands, rectum, salivary glands (mandibular, sublingual), sciatic nerve, seminal vesicles, skeletal muscle, skin, spinal cord (cervical, midthoracic, lumbar), spleen, stomach, testes, tymus, thyroid (including parathyroid gland), tongue, trachea, urinary bladder (filled with formalin at necropsy, uterus, vagina, gross lesions

HISTOPATHOLOGY: Yes , control and high dose group
- histotechnique: organs and tissues were processed, embedded and cut at an approximate thickness of 2 to 4 micrometers and stained with hematoxylin and eosin
-histopathology: slides, which were collected at scheduled sacrifices from all animals of the control and high-dose groups and all gross lesions from all animals were examined by study pathologist. as test item-related morphologic changes were detected in the organs of high-dose animals, the same organs (kidneys, liver and thyroid glands) from animals of te mid- and low-dose groups were examined. Attempts were made to correlate gross observations with microscopic findings.
- tissues and organs examined: adrenal glands, bone marrow (femur), brain (including section of medulla/pons, cerebral and cerebellar cortex), cecum, colon, duodenum, epididymides, heart including auricles, ileum with Peyer's patches, jejunum with Peyer's patches, kidneys, liver, lungs (filled with formalin at necropsy), lymph nodes (mesenteric and mandibular), ovaries, prostate gland including coagulating glands, rectum, sciatic nerve, seminal vesicles, spinal cord (cervical, midthoracic, lumbar), spleen, stomach, testes, thymus, thyroid (including parathyroid gland), trachea, urinary bladder (filled with formalin at necropsy), uterus, vagina, gross lesions

Statistics:

Statistical methods were used to analyze body weight, locomotor activity, grip strength, clinical laboratory data, organ weights, and ratios as well as macroscopic findings:
- Dunnett-test (many to one t-test) based on a pooled variance estimate was applied if the variables could be assumed to follow a normal distribution for the comparison of the treated groups and the control groups for each sex.
- Steel-test (many-one rank test) was applied instead of the Dunnett-test when the data could not be assumed to follow a normal distribution
- Fisher's exact-test

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

Test item-related clinical signs were transient and noted only during daily observation and in rats treated at the highest dose level. The signs included slight sedation (including prostration in one female at 300 mg/kg/day) and ruffled fur. Ataxia was noted in some rats, but all findings were reversible within the first week of treatment, indicating an adaptive response. These findings were considered to be test item-related. Bilateral exophthalmus was noted in one female and was considered to be unrelated to the treatment. No clinical signs were noted during weekly observations.

Mortality:

no mortality observed

Description (incidence):

All animals survived until scheduled necropsy.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

The mean daily body weights and the mean body weight gain of the test item-treated rats compared favorably with those of the controls.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

The mean daily food consumption of the test item-treated rats was unaffected

Food efficiency:

not examined

Water consumption and compound intake (if drinking water study):

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No test item-related changes in hematology were noted at any dose level after the end of the treatment and recovery periods.
Findings noted:
- In males at 300 mg/kg/day: increase in mean absolute number of platelets (p<0.01)
- In females at 300 mg/kg/day: increase in mean corpuscular volume and mean corpuscular hemoglobin (for both, p<0.01); very slight and statistically insignificant reductions in mean number of low-fluorescence reticulocytes and increases in mean number of high-fluorescence reticulocytes
- In males at 100 mg/kg/day: reduction in hemoglobin (dose-unrelated), reduction in mean number of low-fluorescence reticulocytes, increase in mean number of high-fluorescence reticulocytes, and elevated platelets (p<0.05)
- In females at 30 mg/kg/day: reduction of methemoglobin (p<0.05, not toxicologically relevant)
After the recovery period;
- In males at 300 mg/kg/day: prolonged activated thromboplastin time (p<0.05)

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

No test item-related changes in clinical biochemistry were noted at any dose level after the end of the treatment and recovery periods.
Findings noted:
- In males at 300 mg/kg/day: reduction of mean total bilirubin levels (p<0.01), elevated mean cholesterol level (p<0.01), reduction in triglycerides level (not statistically significant), elevated ALAT (p<0.05), elevated calcium (p<0.01) and sodium (p<0.05)
- In females at 300 mg/kg/day: elevated cholesterol (p<0.01), sodium (p<0.05) and triglycerides level (p<0.05)
- In males at 100 mg/kg/day: reduction in albumin (p<0.05)
- In females at 100 mg/kg/day: elevated cholesterol (p<0.01)
- In males at 30 mg/kg/day: reduction in total bilirubin levels (p<0.05)
After the recovery period;
- in females at 300 mg/kg/day: reduction in cholesterol (p<0.05) and potassium
All differences remained within the ranges of historical control ranges and were considered to be unrelated to the test item administration.

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

No test item-related changes were noted at any dose level after the end of the treatment and recovery periods.
- at 300 mg/kg/day: reduced urine pH (p<0.05) and elevated leukocyte number in blood (p<0.05) in males
- at 100 mg:kg/day: elevated number of leukocytes (p<0.05) in blood in males, reduced mean relative density (p<0.05) in females
All differences remained within the ranges of the historical control ranges and were considered to be unrelated to test item administration

Behaviour (functional findings):

no effects observed

Description (incidence and severity):

No clinical signs were noted during the functional observational battery. The mean fore- and hind limb grip strength values and the mean locomotor activity of the test item treated rats were unaffected.

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, non-treatment-related

Description (incidence and severity):

Elevated mean absolute and/or relative liver weights noted in males treated with 30, 100 or 300 mg/kg/day and females treated with 100 or 300 mg/kg/day were considered to be adaptive changes to the metabolism of the test item, but were not considered to be adverse. The differences were reversible after the end of the recovery period.
- at 300 mg/kg/day: increased mean absolute liver weights (p<0.05 males, p<0.01 females), increased mean liver-to-body weights (p<0.01 both sexes), increased mean liver-to-brain wieghts (p<0.05 both sexes)
- at 100 mg/kg/day: increased mean absolute liver weights (p<0.05 males only), increased mean liver-to-body weights (p<0.01 males only), increased mean liver-to-brain weights (p<0.05 males only)
- at 30 mg/kg/day: slightly elevated mean absolute liver weight and mean liver-to-brain weight ratio in males; very marginally higher mean liver-to-body weight ratio in males

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No test item-related macroscopical findings were noted at any dose level.
- at 300 and 100 mg/kg/day: thymic foci after end of treatment in males of each group. Discoloration of mandibular lymph node in one male at 100 mg/kg/day.
- at 300 mg/kg/day at end of the recovery period: thymic foci in a single female

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

T1036 produced effects in the liver of males treated with 100 mg/kg/day and both sexes at 300 mg/kg/day which consisted of minimal to moderate hepatocellular, mainly centrilobular hypertrophy. This finding was not accompanied by increased incidence of inflammatory or degenerative lesions of the liver and resolved in the recovery groups. In the affected groups, the finding of hepatocellular hypertrophy correlated with an increased mean organ weight and organ weight ratios.
In the thyroid glands of rats treated with 30, 100 and 300 mg/kg/day, activation (in terms of increased synthesis/reabsorption phase) of the follicles was recorded. The finding resolved in the recovery groups and was deemed to be of secondary nature due to hepatocellular hypertrophy leading to an increased turnover or hepatic uptake or thyroid hormones.
In the kidneys of male animals treated with 100 and 300 mg/kg/day, increased severity of hyaline droplets was recorded. In males at 300 mg/kg/day, an increased mean severity of tubular basophilia was noted. In one animal at 300 mg/kg/day, focal tubular cell necrosis could be recorded at minimal severity. The latter findings partially resolved in the recovery group. Although these findings of increased hyaline droplets paralleled by increased tubular turnover resemble alpha-2-microglobulin nephropathy are considered adverse in rats, this is generally recognized as species- and gender-specific, and presents no risk to humans.

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Effect levels

Dose descriptor:

NOAEL

Effect level:

100 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical signs

Target system / organ toxicity

Critical effects observed:

yes

Lowest effective dose / conc.:

300 mg/kg bw/day (nominal)

System:

central nervous system

Organ:

not specified

Treatment related:

yes

Dose response relationship:

yes

Relevant for humans:

not specified

Applicant's summary and conclusion

Conclusions:

The purpose of this oral toxicity study was to assess the cumulative toxicity of T1036 when administered daily to rats by gavage for a period of 28 days. The reversibility of test item-related changes was assessed after a treatment-free 14-day recovery period. Based on the results of this study, a NOEL could not be established, but since the only adverse change is specific to the rat, the NOAEL for humans is considered to be 300 mg/kg/day.
Based on the expert statement of study owner (dated 23-04-2014): based on the clinical signs, more specifically ataxia, which was observed at the highest dose level of 300 mg/kg/day, it is suggested to consider 100 mg/kg/day as the NOAEL for occupational toxicology. Based on this expert statement, the LOAEL is 300 mg/kg/day. The test item is therefore to be classified as STOT RE 2 according to CLP Regulation.