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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
The study was performed with a substance analogue and the data are read across.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))
GLP compliance:
yes
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Potassium
EC Number:
231-119-8
EC Name:
Potassium
Cas Number:
7440-09-7
Molecular formula:
K
IUPAC Name:
potassium
Constituent 2
Chemical structure
Reference substance name:
Calcium
EC Number:
231-179-5
EC Name:
Calcium
Cas Number:
7440-70-2
Molecular formula:
Ca
IUPAC Name:
calcium
Constituent 3
Reference substance name:
Ammonium nitrogen
IUPAC Name:
Ammonium nitrogen
Constituent 4
Reference substance name:
Nitrate nitrogen
IUPAC Name:
Nitrate nitrogen
Test material form:
solid: granular
Details on test material:
- Name of test material (as cited in study report): Nitcal/K
- Physical appearance: White granules
- Storage conditions: at room temperature in the dark

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River, Sulzfeld, Germany
- Age at study initiation: 6 weeks
- Weight at study initiation: males: 195-227 g; females: 154-181 g
- Fasting period before study: no
- Housing: group housing (5/sex) in Macrolon cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-23
- Humidity (%):31-73
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 9 February 2007 To: 9 March 2007

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): once
- Mixing appropriate amounts with (Type of food): not applicable
- Storage temperature of food: not indicated

VEHICLE
- Justification for use and choice of vehicle (if other than water): based on trial formulations
- Concentration in vehicle: 5, 10, 100 mg/ml
- Amount of vehicle (if gavage): 10 ml/kg body weight
- Lot/batch no. (if required): not applicable
- Purity: Water (Milli-U) (millipore Corporation, Bedford, USA
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
homogeneity (high- and low dose) and concentration (all doses) were analysed
Duration of treatment / exposure:
28 days
Frequency of treatment:
Daily
Doses / concentrations
Remarks:
Doses / Concentrations:
50, 150, 1000 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
5
Control animals:
yes
Details on study design:
- Dose selection rationale: based on an 8-day dose range finding study (NOTOX project 482737)
Positive control:
no

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: No

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least once daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

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

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): Yes
- Time schedule for examinations: not indicated (subjective appraisal)

OPHTHALMOSCOPIC EXAMINATION: No

HAEMATOLOGY: Yes
- Time schedule for collection of blood: day of necropsy
- Anaesthetic used for blood collection: Yes (iso-flurane)
- Animals fasted: Yes
- How many animals: all animals
- Parameters examined. standard parameters

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: day of necropsy
- Animals fasted: Yes
- How many animals: all animals
- Parameters checked in table [No.?] were examined.

URINALYSIS: No

NEUROBEHAVIOURAL EXAMINATION: Yes
- Time schedule for examinations: during treatment week 4
- Dose groups that were examined: all animals
- Battery of functions tested: hearing ability / grip strength / motor activity / righting reflex/ pupillary reflex:

Sacrifice and pathology:
GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes, all selected tissues from control and high dose animals, gross lesions (all animals), stomach and spleen (all dose levels)
Other examinations:
Organ weights
Statistics:
Yes

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:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Details on results:
HAEMATOLOGY: high-dose males: reticulocytes and red cell distribution width slightly increased; high-dose females: red blood cell count and haematocrit slightly decreased. Reviewer: these changes are not consistent between males/females, are very slight, and three out of four appeared to be in the historical control range from this strain (based on NOTOX historical data) and this kind of study. Therefore, not considered adverse.

GROSS PATHOLOGY: thickened limiting ridge and/or foci in glandular mucosa in 2 and 3 high-dose males and females, respectively. This is a local effect and reversible.

HISTOPATHOLOGY: NON-NEOPLASTIC: hyperplasia/hyperkeratosis of the limiting ridge of the stomach in 4 and 3 high dose males and females, respectively; increased severity of haemopoietic foci (erythroid) in the spleen at high dose. Reviewer: The effect in the stomach is a local effect and reversible. The effect in the spleen is limited to one male and one female with a moderate severity at the high dose. However, this is a symptom expected in young animals in such a study, in addition it is considered a reversible effect. This is based on expertise of experienced pathologist.

Effect levels

Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Author considered 150 mg/kg bw as a NOAEL, however no adverse effects at highest dose tested according to reviewer. See discussion.

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

The treatment-related changes in hematology parameters and spleen morphology at high dose point a slightly increased red blood cell turnover

Applicant's summary and conclusion

Conclusions:
Based on effects noted at high dose (1000 mg/kg body weight/day), the NOAEL of Nitcal/K was considered tobe 150 mg/kg body weight/day in a 28-day oral (gavage) study in rats