Nitric acid, ammonium calcium salt

Repeated dose toxicity: oral

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 has been performed according to OECD and/or EC guidelines and according to GLP principles. However, since the study was performed with a substance analogue and the data are read across, the Klimisch score is 2.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

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))

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

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

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