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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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well performed GLP and OECD guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method B.7 (Repeated Dose (28 Days) Toxicity (Oral))
Deviations:
no
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

Test material

Constituent 1
Reference substance name:
Manganese Oxalate, dihydrate
IUPAC Name:
Manganese Oxalate, dihydrate

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS

- Animals: Rat, RccHanTM: WIST(SPF)
- Rationale: Recognized by international guidelines as a recommended test system.
- Breeder: Harlan Laboratories B.V., Kreuzelweg 53, 5961 NM Horst / Netherlands
- Number of Animals: 5 males and 5 females in each of groups 1 to 4
- Age (at Delivery): 7 weeks
- Body Weight Range (at Acclimatization): 174 to 209 g (mean 191 g) in males and 124 to 148 g (mean 133 g) in females
- Identification: During acclimatization by cage card and tail mark (later by ear tattoo), and during treatment by cage card and individual ear tattoo
- Randomization: Randomly allocated to groups by body weight.
- Acclimatization: Under test conditions after health examination. Only animals without any visible signs of illness were used for the study.

ENVIRONMENTAL CONDITIONS

- Conditions: Standard laboratory conditions. Air-conditioned with 10 - 15 air changes per hour, continuously monitored environmental conditions (temp. range: 22 ± 3 °C; relative humidity range: 30 - 70%). Humidity values outside of these ranges occasionally occurred, usually following room cleaning, and are considered not to have any influence on the study. Therefore, these data are not reported but are retained at Harlan Laboratories Ltd. The light cycle was set to 12-hour fluorescent light / 12-hour dark cycle with at least eight hours music during the light period.
- Accommodation: In groups of five in Makrolon type-4 cages with wire mesh tops and standard softwood bedding (J. Rettenmaier & Söhne GmbH & Co. KG, 73494 Rosenberg / Germany, imported by Provimi Kliba AG, 4303 Kaiseraugst / Switzerland) including paper enrichment (Enviro-dri from Lillico, Biotechnology, Surrey / UK).
- Diet: Pelleted standard Harlan Teklad 2914C (batch no. 73/11) rat / mouse maintenance diet (Provimi Kliba AG, 4303 Kaiseraugst / Switzerland) was available ad libitum. The feed batch was analyzed for contaminants.
- Water: Community tap-water from Itingen was available ad libitum in water bottles. A bacteriological assay, chemical and contaminant analyses of respective samples was performed.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
CMC (carboxymethyl cellulose)
Details on oral exposure:
DOSE FORMULATIONS

The dose formulations were corrected for the anhydrous substance (Manganese Oxalate) using a conversion factor of 1.252.

The dose formulations were prepared daily as indicated by the results of stability analyses in the Harlan Laboratories dose range-finding study. Analysis for stability after 8 days was evaluated in this study.

MANGANESE OXALATE, DIHYDRATE was weighed into a glass beaker on a tared Mettler balance. The vehicle was added and the mixtures were stirred using a magnetic stirrer and used at room temperature (20 ± 5 °C).

Homogeneity of the test item in the vehicle was maintained during the daily administration period using a magnetic stirrer.

STABILITY AND STORAGE OF DOSE FORMULATIONS

The dose formulations were stable at least 4 hours based upon the results of stability analyses performed during the non-GLP Harlan Laboratories dose range-finding study). The stability at least up to 8 days was confirmed in this study.

The dose formulations were stored in glass beakers at room temperature (20 ± 5 °C).

TREATMENT

- Method: Oral, by gavage
- Rationale for Method: Administration by gavage is a common and accepted route of exposure for studies of this type.
- Frequency of Administration: Daily.
- Dose Levels: 0 mg/kg bw/day (Group 1), 100 mg/kg bw/day (Group 2), 300 mg/kg bw/day (Group 3) and 1000 mg/kg bw/day (Group 4)
- Rationale for Dose Level Selection: The dose levels were selected based on a previous Harlan Laboratories dose range finding toxicity study in Wistar rats (non-GLP).
- Dose Volume: 10 mL/kg body weight
- Dose Concentrations: 0 mg/mL/day (Group 1), 10 mg/mL/day (Group 2), 30 mg/mL/day (Group 3) and 100 mg/mL/day (Group 4)
- Duration of Pre-Randomization Phase: 1 day
- Duration of Acclimatization Phase: 4 days
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
METHOD

The analysis was performed by Harlan Laboratories Ltd. using an HPLC-UV method provided by the Sponsor.

After experimental start and during week 3, samples of the control group as well as three samples (top, middle and bottom) of about 2 g of each concentration were taken prior to dosing for analysis of homogeneity and concentration. Samples of about 2 g of each concentration were taken after experimental start to confirm stability (4 hour and 8 days).

The samples were delivered under ambient conditions to the analytical department at Harlan Laboratories Ltd. (Itingen / Switzerland) and either directly analysed or stored there at -20 ± 5 °C until analysis.

The test item was used as analytical standard.

Dose formulation samples and duplicate samples stored in the toxicology department were discarded upon written confirmation by the study director after acceptance of the draft report.

RESULTS

The linearity of the analytical systems used for sample analyses was demonstrated with a good relationship between peak areas measured and working standard concentrations. All calibration points used met the acceptance limit of ±20% variation from the calibration curve derived by linear/power regression analysis. The regression coefficients (R2) exceeded 0.99.

The test item peak was assigned in sample chromatograms by comparison to that of working standards. In blank sample chromatograms, no peak appeared at the retention time of the test item, confirming the absence of the test item in the vehicle control samples (0.5% aqueous solution of carboxymethylcellulose).

The application formulations investigated during the study were found to comprise MANGANESE OXALATE, DIHYDRATE in the range of 82.0% to 97.1%, meeting the required content limit of ±20% with reference to the nominal content.

Single results found did not deviate more than 1.7% (acceptance criterion: <15%) from the corresponding mean, confirming the homogeneous distribution of test item in the preparations.

In addition, the test item was found to be stable in application formulations when kept 8 days at room temperature, as recoveries met the variation limit of 10% from the time-zero (homogeneity) mean.

In conclusion, the results indicate the accurate use of the test item MANGANESE OXALATE, DIHYDRATE and 0.5% aqueous solution of carboxymethylcellulose as vehicle during this study. Application formulations were found to be homogeneously prepared and sufficiently stable under storage conditions.
Duration of treatment / exposure:
28 days
Frequency of treatment:
Once daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 100, 300 and 1000 mg/kg bw/day (nominal)
Basis:
other: in terms of Manganese Oxalate, anhydrous form (= submission substance)
No. of animals per sex per dose:
5 males and 5 females
Control animals:
yes, concurrent vehicle
Details on study design:
In this subacute toxicity study, MANGANESE OXALATE, DIHYDRATE was administered daily by oral gavage to SPF-bred Wistar rats of both sexes at dose levels of 100, 300 and 1000 mg/kg body weight/day for a period of 28 days. A control group was treated similarly with the vehicle, 0.5% aqueous solution of carboxymethylcellulose (CMC), only.

The groups comprised 5 animals per sex which were sacrificed after 28 days of treatment.

Clinical signs, outside cage observation, food consumption and body weights were recorded periodically during the acclimatization and treatment period. Functional observational battery, locomotor activity and grip strength were performed during week 4.

At the end of the dosing period, blood samples were withdrawn for hematology and plasma chemistry analyses. All animals were killed, necropsied and examined post mortem. Histological examinations were performed on organs and tissues from all control and high dose animals, and all gross lesions from all animals.
Positive control:
Not required

Examinations

Observations and examinations performed and frequency:
VIABILITY/MORTALITY

Observations for viability / mortality were recorded twice daily.

DAILY OBSERVATIONS

The animals were observed for clinical signs once daily before commencement of administration as well as daily on days 1 - 28 (twice daily during days 1 - 3) during the treatment period.

WEEKLY BEHAVIORAL OBSERVATIONS

The animals were observed in their home cages, outside their home cages in a standard arena and in the hand. These observations were performed once before commencement of administration and once weekly (weeks 1 to 3) thereafter. More details on the investigations can be found in the section “Any other information on materials and methods incl. tables” below.

FUNCTIONAL OBSERVATIONAL BATTERY (SCREEN)

During week 4, relevant parameters from a modified Irwin screen test were evaluated in all animals.

- Grip Strength: Forelimb and hindlimb grip strength measurements were performed using a push-pull strain gauge (Mecmesin, AFG 25N). 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, the 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 Activity Monitor System. Animals were monitored during the fourth treatment week for a 60-minute period and the total activity of this time period was recorded. Low beams count was reported in 10-minute intervals as well as the total activity of the measuring period.

FOOD CONSUMPTION

The food consumption was recorded once during the acclimatization period and weekly thereafter, using an on-line electronic recording system consisting of a Mettler balance connected to the Harlan Laboratories computer.

BODY WEIGHTS

Body weights were recorded weekly during acclimatization, treatment period and before necropsy, using an on-line electronic recording system consisting of a Mettler balance connected to the Harlan Laboratories computer.

CLINICAL LABORATORY INVESTIGATIONS

Blood Sampling after 4 Weeks: 02-Jul-2012

Blood samples were drawn from the retro-orbital plexus from all animals under light isoflurane anesthesia. The animals were fasted for approximately 18 hours before blood sampling but allowed access to water ad libitum. The samples were collected early in the working day to reduce biological variation caused by circadian rhythms. Blood samples were drawn from the retro-orbital plexus using a micro-hematocrit glass capillary tube.

Clinical laboratory data are expressed, with a few exceptions, in general accordance with the International System of Units (SI).

The following hematology parameters were determined:

- 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)
- Leukocyte count, total
- Differential leukocyte count:
- Neutrophils
- Eosinophils
- Basophils
- Lymphocytes
- Monocytes
- Large unstained cells
- Platelet count
- Methemoglobin
- Heinz bodies (slides were prepared but not evaluated)
- Prothrombin time (= Thromboplastin time)
- Activated partial Thromboplastin time

The following clinical biochemistry parameters were determined:

- Glucose
- Urea
- Creatinine
- Bilirubin, total
- Cholesterol, total
- Triglycerides
- Phospholipids
- Aspartate aminotransferase
- Alanine aminotransferase
- Lactate dehydrogenase
- Alkaline phosphatase
- Bile acids
- Gamma-glutamyl-transferase
- Creatine kinase
- Sodium
- Potassium
- Chloride
- Calcium
- Phosphorus
- Protein, total
- Albumin
- Globulin
- Albumin/Globulin ratio
Sacrifice and pathology:
TERMINATION AND NECROPSY

Sacrifice after 4 Weeks: 02-Jul-2012

All animals were weighed and necropsied. Descriptions of all macroscopical abnormalities were recorded. All animals surviving to the end of the observation period were anesthetized by intraperitoneal injection of pentobarbitone and killed by exsanguination.

Samples of the following tissues and organs were collected from all animals at necropsy and fixed in neutral phosphate buffered 4% formaldehyde solution unless indicated otherwise.

- 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 (fixed in Bouin's solution)
- Esophagus
- Eyes w/optic nerve (fixed in Davidson's solution)
- Harderian gland (fixed in Davidson's solution)
- Heart including auricles
- Ileum, with Peyer's patches
- Jejunum with Peyer's patches
- Kidneys
- Larynx
- Lacrimal gland, exorbital
- Liver
- Lungs, filled w/formalin at necropsy
- Lymph nodes – mesenteric and mandibular
- Mammary gland area
- Nasal cavity
- Ovaries
- Pancreas
- Pharynx
- Pituitary gland
- Seminal vesicles/Prostate gland incl. coagulating glands
- Rectum
- Salivary glands - mandibular, sublingual
- Sciatic nerve
- Skeletal muscle
- Skin
- Spinal cord - cervical, midthoracic, lumbar
- Spleen
- Stomach
- Testes (fixed in Bouin's solution)
- Thymus
- Thyroid (incl. parathyroid gland, if possible)
- Tongue
- Trachea
- Urinary bladder, filled w/formalin at necropsy
- Uterus, including oviducts, cervix and vagina
- All gross lesions

ORGAN WEIGHTS

The following organs from all animals 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.

- Adrenal glands
- Brain - including section of medulla/pons, cerebral and cerebellar cortex
- Epididymides (fixed in Bouin's solution)
- Heart including auricles
- Kidneys
- Liver
- Ovaries
- Pituitary gland
- Seminal vesicles/Prostate gland incl. coagulating glands
- Spleen
- Testes (fixed in Bouin's solution)
- Thymus
- Thyroid (incl. parathyroid gland, if possible)
- Uterus, including oviducts, cervix and vagina

The terminal body weight was recorded immediately prior to necropsy and the organ to terminal body weight ratios as well as organ to brain weight ratios were determined.

HISTOTECHNIQUE

All organ and tissue samples to be examined as stated below were processed, embedded and cut at an approximate thickness of 2 to 4 micrometers and stained with hematoxylin and eosin.

HISTOPATHOLOGY

Slides of all organs and tissues listed below collected at the scheduled sacrifice from all animals of the control and high-dose groups and all gross lesions from all animals were examined by the study pathologist.

- Adrenal glands
- Bone marrow (femur)
- Brain - including section of medulla/pons, cerebral and cerebellar cortex
- Cecum
- Colon
- Duodenum
- Epididymides (fixed in Bouin's solution)
- Eyes w/optic nerve (fixed in Davidson's solution)
- Heart including auricles
- Ileum, with Peyer's patches
- Jejunum with Peyer's patches
- Kidneys
- Liver
- Lungs, filled w/formalin at necropsy
- Lymph nodes – mesenteric and mandibular
- Ovaries
- Pituitary gland
- Seminal vesicles/Prostate gland incl. coagulating glands
- Rectum
- Sciatic nerve
- Skeletal muscle
- Spinal cord - cervical, midthoracic, lumbar
- Spleen
- Stomach
- Testes (fixed in Bouin's solution)
- Thymus
- Thyroid (incl. parathyroid gland, if possible)
- Trachea
- Urinary bladder, filled w/formalin at necropsy
- Uterus, including oviducts, cervix and vagina
- All gross lesions

Organ and tissue samples taken from animals which died spontaneously were evaluated similarly to those organs taken from animals of the high-dose group.

Attempts were made to correlate gross observations with microscopic findings. A peer review of the histopathology phase report was performed. The findings of the study pathologist and the peer-reviewing pathologist compared favorably.
Other examinations:
At necropsy, a blood sample was taken from each animal by heart puncture (ca. 2 mL) into appropriate tubes (Vacutainer glass tubes containing SST-Gel and Clot Activator) for serum preparation and then placed on ice. Following centrifugation, the serum was divided in 2 aliquots of at least 350 µL and transferred to plastic (polypropylene) tubes. These samples were stored at approximately -80 °C and protected from light pending analysis of hormone activity, which was not considered necessary.
Statistics:
The following statistical methods were used to analyze body weight, grip strength, locomotor activity, clinical laboratory data, organ weights and ratios as well as macroscopic findings:

- The 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.
- The 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:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
At 1000 mg/kg bw/day, slightly lower mean absolute and relative body weights were noted in males from day 15 onwards
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
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:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
not examined
Details on results:
1. IN-LIFE DATA

VIABILITY/MORTALITY

All animals survived the scheduled treatment period. On the day of necropsy, male no. 15 treated at 300 mg/kg bw/day died during anesthesia for blood sampling.

DAILY OBSERVATIONS

No findings were noted during the treatment period.

WEEKLY BEHAVIORAL OBSERVATIONS

There were no clinical signs noted at any dose level during the weekly behavioral observations performed during weeks 1 or 2.

Decreased activity was noted in all males treated at 300 mg/kg bw/day during the weekly behavioral observations at week 3. The effects observed were unrelated to dose and therefore considered to be incidental.

FUNCTIONAL OBSERVATIONAL BATTERY (SCREEN)

No findings were evident during the functional observational battery performed at week 4 of treatment.

- Grip Strength: The mean fore- and hind limb grip strength values of the test item-treated males and females compared favorably with those of the respective control values. The significantly increased values for hindlimb grip strength (males, p<0.05) and forelimb grip strength (females, p>0.01) noted at 300 mg/kg/day were unrelated to dose and therefore considered to be incidental.

- Locomotor Activity: The mean locomotor activity values of the test item-treated males and females were considered to be unaffected by treatment.

FOOD CONSUMPTION

There were no test item-related changes in the mean daily food consumption at any dose level.

A marginal decrease in mean daily relative food consumption in the males treated at 300 or 1000 mg/kg bw/day was recorded in the last week of treatment although the mean over the treatment period was not affected. The females were not affected.

BODY WEIGHTS

The mean absolute and relative body weights at 100 or 300 mg/kg bw/day compared favorably with the respective control values.

At 1000 mg/kg bw/day, slightly lower mean absolute and relative body weights were noted in males from day 15 onwards. The absolute values were statistically significant on day 22 (p<0.01) and on days 15 and 28 (both p<0.05) and the relative values were statistically significant on day 22 (p<0.01) and on day 28 (p<0.05) when compared with the control values. The females were not affected.

2. CLINICAL LABORATORY INVESTIGATIONS

HEMATOLOGY

There were no test item-related changes upon the hematology parameters of males or females at any dose level.

At 1000 mg/kg bw/day, statistically significant elevated absolute basophils (p<0.05) was noted in females when compared with the controls. This difference was not seen in the relative value and, as the values were within the range of the historical control data, was considered to be incidental.

CLINICAL BIOCHEMISTRY

There were no test item-related changes upon the clinical biochemistry parameters of males or females at any dose level.
At 1000 mg/kg bw/day, statistically significant elevated triglycerides (p<0.05), aspartate aminotransferase levels (p<0.05) in the males and statistically significant lower albumin (p<0.05) in the females were noted when compared with the controls. At 300 and 1000 mg/kg bw/day, statistically significant lower total bilirubin (p<0.05) and phosphate levels (p<0.05) in the females were noted when compared with the controls. These differences remained within the range of the historical control data, except mean phosphate values, and were considered to be incidental. The phosphate outliers marginally exceeded the lower range of the historical control data and were considered not to be toxicologically relevant.

3. PATHOLOGLY

ORGAN WEIGHTS

There were no statistically significant differences in the mean absolute and relative organ weights at any dose level.

MACROSCOPICAL FINDINGS

There were no test item-related macroscopical changes in males or females after 4 weeks’ treatment. A low incidence of macroscopical findings was noted in males and females at all dose levels with no clear dose dependent relationship.

MICROSCOPIC FINDINGS

There were no microscopic findings that could be attributed to the treatment with the test item. All findings recorded were within the range of normal background lesions which may be recorded in animals of this strain and age.

In the decedent animal, congestion and alveolar edema recored in the lung were considered to be related to the spontaneous death.

Effect levels

Dose descriptor:
NOAEL
Effect level:
1 000 mg/kg bw/day (nominal)
Based on:
other: in terms of Manganese Oxalate, anhydrous form (= submission substance) , equivalent to 1252 mg/kg bw. of the test item (Manganese Oxalate, dihydrate)
Sex:
male/female
Basis for effect level:
other: No adverse effects up to the highest dose tested

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
Oral administration of MANGANESE OXALATE, DIHYDRATE to Wistar rats at dosages of 100, 300, and 1000 mg/kg body weight/day (in terms of Manganese Oxalate, anhydrous form, which is equivalent to 125.2, 375.6 and 1252 mg/kg body weight/day of the test item), for 28 days resulted in no deaths of toxicological relevance, no clinical signs during daily or weekly observations, no clinical signs during the functional observational battery at week 4, no effects on fore- or hindlimb grip strength or on locomotor activity, and no effects on mean food consumption. The various parameters of hematology and clinical biochemistry were not affected by treatment. The mean absolute and relative organ weights of the controls and test item-treated animals compared favorably. There were neither macroscopical nor microscopical changes that could be attributed to the test item.

Test item-related findings were generally restricted to very marginal changes in the body weight development of males treated with 1000 mg/kg/day. In the absence of similar changes in females, these minor effects were considered to be not adverse.

Based on the results of this study, 1000 mg/kg body weight/day in terms of MANGANESE OXALATE, anhydrous form was established as the no-observed-adverse-effect-level (NOAEL).
Executive summary:

GENERAL

 

In this subacute toxicity study, MANGANESE OXALATE, DIHYDRATE was administered daily by oral gavage to SPF-bred Wistar rats of both sexes at dose levels of 100, 300 and 1000 mg/kg/day in terms of Mangenese oxalate, anhydrous form for a period of 28 days. A control group was treated similarly with the vehicle, 0.5% aqueous solution of carboxymethylcellulose (CMC), only.

 

The groups comprised 5 animals per sex which were sacrificed after 28 days of treatment.

 

Clinical signs, outside cage observation, food consumption and body weights were recorded periodically during the acclimatization and treatment period. Functional observational battery, locomotor activity and grip strength were performed during week 4.

At the end of the dosing period, blood samples were withdrawn for hematology and plasma chemistry analyses. All animals were killed, necropsied and examined post mortem. Histological examinations were performed on organs and tissues from all control and high dose animals, and all gross lesions from all animals.

 

MORTALITY / VIABILITY

 

There were no toxicologically relevant deaths. One mid dose male died during anesthesia for blood sampling.

 

CLINICAL SIGNS (DAILY AND WEEKLY)

 

No test item-related findings were noted in the daily clinical observations performed during the treatment period.

 

No test item-related findings were evident during the weekly behavioral observations.

 

FUNCTIONAL OBSERVATIONAL BATTERY

 

No findings were evident during the functional observationsl battery performed at week 4 of treatment.

 

GRIP STRENGTH

 

The mean fore- and hind limb grip strength values of the test item-treated males and females compared favorably with those of the respective control values.

 

LOCOMOTOR ACTIVITY

 

The mean locomotor activity values of the test item-treated males and females were considered to be unaffected.

 

FOOD CONSUMPTION

 

There were no test item-related changes in the mean daily food consumption at any dose level.

 

A marginal decrease in mean daily relative food consumption was recorded in the males treated at 300 or 1000 mg/kg bw/day in the last week of treatment. The mean relative food consumption over the treatment period was not affected. The females were not affected.

 

BODY WEIGHTS

 

The mean absolute and relative body weights of the test item-treated rats at 100 or 300 mg/kg bw/day compared favorably with the respective control values during the treatment period.

 

At 1000 mg/kg bw/day, slightly lower mean absolute and relative body weights were noted in males from day 15 onwards when compared with the control values. The females were not affected.

 

CLINICAL LABORATORY INVESTIGATIONS

 

- Hematology: There were no test item-related changes upon the hematology parameters of males or females at any dose level.

 

- Clinical Biochemistry: There were no test item-related changes upon the clinical biochemistry parameters of males or females at any dose level.

 

ORGAN WEIGHTS

 

There were no statistically significant differences in the mean absolute and relative organ weights of males or females at any dose level.

 

MACROSCOPIC / MICROSCOPIC FINDINGS

 

After 4 weeks treatment a small number of macroscopical findings was noted in rats at all dose levels with no clear dose dependent incidence.

 

There were no microscopic findings that could be attributed to the treatment with the test item.

 

CONCLUSION

 

Based on the results of this study, 1000 mg/kg body weight/day in terms of MANGANESE OXALATE, anhydrous form was established as the no-observed-adverse-effect-level (NOAEL).