Piperidine, 4-(4-iodo-1H-pyrazol-1-yl)-

Endpoint summary

Description of key information

Two studies are available:
1) A repeated dose 28-day oral toxicity study by daily gavage in rat (Beerens-Heijnen, 2011) is available which is key study. This study showed that No Observed Adverse Effect Level (NOAEL) for the test substance is 75 mg/kg. 
2) A dose range finding study (Beerens-Heijnen, 2011) is available which is supporting study. This study showed that dose levels suggested for the main study are 10, 25 and 75 mg/kg body weight.

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:

From 1 January to 08 February 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted in compliance with GLP regulations and according to a recognised test guideline.

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Approximately 6 weeks.
- Weight at study initiation: Males weighed 160-162 g on day 1, while females weighed 128-132 g.
- Fasting period before study: No data.
- Housing: Group housing of 5 animals per sex in Macrolon cages with sterilized sawdust as bedding material and paper as cage-enrichment. During locomotor activity monitoring, animals were housed individually in a Hi-temp polycarbonate cage without cage-enrichment or bedding material. Certificates of analysis were examined and then retained in the NOTOX archives.
- Diet (e.g. ad libitum): Free access to pelleted rodent diet.
- Water (e.g. ad libitum): Free access to tap water.
- Acclimation period: At least 5 days before the start of treatment under laboratory conditions.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.0 ± 3.0°C (actual range: 19.2-22.4°C)
- Humidity (%): 40-70% (actual range: 30-73%)
- Air changes (per hr): Approximately 15
- Photoperiod (hrs dark / hrs light): 12 hours artificial fluorescent light and 12 hours darkness per day

IN-LIFE DATES: From: 11 January 2011 To: 07 February 2011

Route of administration:

oral: gavage

Vehicle:

other: 1% Aqueous carboxymethyl cellulose

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency):
- Mixing appropriate amounts with (Type of food):
- Storage temperature of food:

VEHICLE
- Justification for use and choice of vehicle (if other than water): Based on trial formulations performed at NOTOX and on information from the sponsor.
- Concentration in vehicle:
- Amount of vehicle (if gavage): 5 mL/kg body weight/day
- Lot/batch no. (if required):
- Purity:

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

UPLC

Duration of treatment / exposure:

28 days

Frequency of treatment:

Once daily, 7 days per week, approximately the same time each day with a maximum of 6 hours difference between the earliest and latest dose.

Remarks:

Doses / Concentrations:
10, 25 and 75 mg/kg
Basis:
actual ingested

No. of animals per sex per dose:

5 male and 5 female

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: No data
- Time schedule:
- Cage side observations checked in table [No.?] were included.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: At least once daily from start of treatment until Day 4 of treatment. From Day 5 of treatment onwards clinical observations were conducted at least immediately after dosing and between 1 and 2 hours after dosing.

BODY WEIGHT: Yes
- Time schedule for examinations: Weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data

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: Yes

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: Subjective appraisal was maintained during the study, but no quantitative investigation introduced as no effect was suspected.

OPHTHALMOSCOPIC EXAMINATION: No data
- Time schedule for examinations:
- Dose groups that were examined:

HAEMATOLOGY: Yes
- Time schedule for collection of blood: Immediately prior to scheduled post mortem examination, between 7.00 and 10.30 a.m. at the end of the treatment phase.
- Anaesthetic used for blood collection: Yes (using an isoflurane in nitrous oxide/oxygen)
- Animals fasted: Yes
- How many animals: 40
- Parameters checked in table [No.?] were examined.

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Immediately prior to scheduled post mortem examination, between 7.00 and 10.30 a.m. at the end of the treatment phase.
- Animals fasted: Yes
- How many animals: 40
- Parameters checked in table [No.?] were examined.

URINALYSIS: No data
- Time schedule for collection of urine:
- Metabolism cages used for collection of urine:
- Animals fasted:
- Parameters checked in table [No.?] were examined.

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: Between 1 and 2 hours after dosing.
- Dose groups that were examined: All animals
- Battery of functions tested: Motor activity

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes

Other examinations:

None

Statistics:

None stated

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

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:

effects observed, treatment-related

Urinalysis findings:

not specified

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:

effects observed, treatment-related

Histopathological findings: neoplastic:

no effects observed

Details on results:

Observations
Mortality:
No mortality occurred during the study period.

Clinical signs:
All males and females at 75 mg/kg showed calm behavior, hunched posture and/or piloerection predominantly during the first three weeks of the observation period. Tremors were noted at a lower incidence during the last two weeks of the observation period.
No clinical signs of toxicity were noted in control animals and at 10 and 25 mg/kg during the observation period.
The slight degree of salivation shown among the animals at 75 mg/kg/day (and one animal at 25 mg/kg) is often noted in rats of this age and strain following oral gavage and may be related to taste of the test substance. Therefore salivation was not considered to be of toxicological relevance.
Scabs in the neck, incidentally noted at 10 and 25 mg/kg occurred within the range of background findings to be expected for rats of this age and strain which are housed and treated under the conditions in this study. At the incidence observed, this was considered a sign of no toxicological significance.

Functional observations:
The variation in motor activity did not indicate a relation with treatment.

Body weights:
Body weights and body weight gain of treated animals remained in the same range as controls over the study period.
The statistically significant lower body weight gain of females at 75 mg/kg was only seen in Week 2 and recovered during the study. Therefore this was not considered to be toxicologically significant.

Food consumption:
Food consumption before or after allowance for body weight was similar between treated and control animals.

Clinical laboratory investigations
Haematology:
No toxicologically relevant changes occurred in haematological parameters of the females.
Slightly higher heamatocrit levels and slightly higher red blood cells (not statistically significant) were noted in males at 25 and 75 mg/kg. In addition slightly lower mean corpuscular heamoglobin concentration (MCHC) was noted in males at 25 mg/kg only. These values remained within the range considered normal for rats of this age and strain and occurred in the absence of a clear dose response distribution and no corroborative findings were noted in microscopic examination. Therefore, these findings were considered to be not toxicologically significant.

Clinical biochemistry:
The following statistically significant changes in clinical biochemistry parameters distinguished treated animals from control animals:
• Slightly lower total protein in males at 75 mg/kg
• Higher alanine aminotransferase activities in females at 75 mg/kg (predominantly animal 37, which also showed higher aspartate aminotransferase (ASAT) activity)
• Lower creatinine and chloride levels in females at 25 and/or 75 mg/kg
• Higher bile acid, potassium, calcium and inorganic phosphate levels in females at 75 mg/kg
• Slightly higher cholesterol levels in females at 75 mg/kg (not statistically significant).
Any other statistically significant changes in males at 10 and/or 25 mg/kg were considered to be of no toxicological significance as they occurred in the absence of a treatment-related distribution and/or remained within the range considered normal for rats of this age and strain. These findings included higher bile acids, higher chloride and sodium level.

Pathology
Macroscopic examination:
Macroscopic observations at necropsy did not reveal any alterations that were considered to have arisen as a result of treatment.
The incidence of fluid in the uterus and foci on the clitoral gland was within the background range of findings that are encountered among rats of this age and strain, and did not show a dose-related incidence trend. These necropsy findings were therefore considered to be of no toxicological significance.

Organ weights:
The following (statistically significant) changes in organ weights distinguished treated animals from control animals:
• Higher relative liver and/or kidney weight in males and females at 75 mg/kg
Lower absolute thymus weight and higher relative thyroid weight in males at 75 mg/kg were considered to be due to a slightly lower terminal body weight and/or occurred in the absence of a clear dose related distribution.
The higher testes, epididymides and seminal vesicle weights (absolute and/or relative) in males at 10 and 75 mg/kg and higher absolute liver weight in females at 10 mg/kg remained within the range considered normal for rats of this age and strain and were not accompanied by morphological evidence of organ dysfunction. Therefore these findings were considered to be not toxicologically significant.

Microscopic examination:
There were treatment-related microscopic findings in the kidneys and liver of males at 75 mg/kg.
Cortical hyaline droplets representing alpha2μglobulin were recorded at increased incidence (5/5) and severity (minimal-slight) in the kidneys of these males. This was accompanied by hyaline casts (slight), granular cast (minimal) and increased severity of corticomedullary tubular basophilia (moderate) in one male. These latter findings were considered as indicators of renal tubular damage due to the increase in hyaline droplets.
In the liver hepatocellular hypertrophy was recorded at minimal degree at this dose level in males
(4/5).
All other microscopic findings were within the range of background pathology encountered in Wistar rats of this age and strain and occurred at similar incidences and severity in both control and treated rats.

Dose descriptor:

NOAEL

Effect level:

75 mg/kg bw/day (actual dose received)

Based on:

act. ingr.

Sex:

male/female

Basis for effect level:

other: No toxicologically adverse effects at highest dose level tested

Critical effects observed:

not specified

Conclusions:

From the results presented in this report a definitive No Observed Adverse Effect Level (NOAEL) for this substance of 75 mg/kg was established.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

75 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

1 (reliable without restriction)

Additional information

Repeated dose toxicity: oral

Two studies are available:

1) A repeated dose 28-day oral toxicity study was conducted according to OECD 407 using rats (Beerens-Heijnen, 2011). Key study.

This study showed that No Observed Adverse Effect Level (NOAEL) for the test substance is 75 mg/kg.

2) A dose range finding study (Beerens-Heijnen, 2011) was conducted to set the dose levels for the main study. Supporting study.

Based on the results of this range finding study, dose levels suggested for the main study (28-day oral toxicity study) are 10, 25 and 75 mg/kg body weight. The peak effect of occurrence of clinical signs occurred approximately 1 hour after dosing. Therefore clinical observations in the main study were observed between 1 and 2 hours after dosing.

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
The study was conducted in compliance with GLP regulations and according to a recognised test guideline.

Justification for classification or non-classification

Oral: LOAEL > 75 mg/kg bw in a study

Therefore in accordance with Regulation (EC) No. 1272/2008 Table 3.9.2 and 3.9.3 the substance is not classified for the repeated oral toxicity endpoint.