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Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Details on test material:

- Test article: CGA65047 SG 100 (A-5787 A)
- Physical state: granules
- Analytical purity: 100 % (UVCB)
- Lot/batch No.: P.201845
- Storage condition of test material: room temperature

Test animals

Species:

rat

Strain:

other: Sprague-Dawley derived; Tif:RAIf (SPF); hybrids of RII/1 x RII/2

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Animal Production, Novartis Pharma AG, 4332 Stein, Switzerland
- Age at start of acclimation period: approximately 5 weeks old
- Weight range at acclimation period: 149.5-185.8 g (males), 134.7-165.6 g (females)
- Housing: in groups of 5 animals, in macrolon cages type 4 with wire mesh tops and standardised granulated soft wood bedding
- Diet: pelleted, certified standard diet (Nafag No. 8900 FOR GLP), provided ad libitum (exception: food was withheld overnight prior to blood collection)
- Water: tap water, ad libitum
- Acclimation period: 11 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 2 °C
- Humidity: 55 ± 10 %
- Air changes: 16-20 air changes/hour
- Photoperiod: 12 hours dark / 12 hours light

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5 % CMC and 0.1 % Tween 80 in distilled water

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS:
Suspensions of the test article in the vehicle at the appropriate concentrations were freshly prepared every day immediately prior to the dosing of the animals and administered within about 2 hours.

VEHICLE
- Justification for use and choice of vehicle: standard procedure
- Amount of vehicle: 10 mL/kg bw of suspension were applied

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Control analyses of the test article in the vehicle were carried out at all dose levels on samples collected once per experimental weeks 1, 4, 8 and 13. Samples were analysed by RCC Umweltchemie AG, 4452 Itingen, Switzerland (RCC Project Number 651688).

Duration of treatment / exposure:

90 days

Frequency of treatment:

once per day, 7 times per week

Doses / concentrations

Remarks:

Doses / Concentrations:
5, 50 and 200 mg/kg bw/day
Basis:
actual ingested

No. of animals per sex per dose:

Main Experiment: 10 animals
Recovery: 10 animals (control and high dose group only)

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: dose levels were selected based on the results of a preceding 28-day dose range finding toxicity study, project no. 941102 (CIBA-GEIGY, 1996).
- Post-exposure recovery period in satellite groups: 4 weeks

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS:
- Time schedule: twice daily for mortality and once daily for general observations.

DETAILED CLINICAL OBSERVATIONS:
- Time schedule: at least weekly

BODY WEIGHT:
- Time schedule: once weekly

FOOD CONSUMPTION:
- Food consumption was determined cagewise on a weekly basis and mean daily diet consumption calculated as g food/kg bw/day.

WATER CONSUMPTION
- Time schedule for examinations: weekly, determined cagewise

OPHTHALMOSCOPIC EXAMINATION:
- Time schedule for examinations: during the acclimation period (all animals), at the end of the treatment and recovery periods (control and high dose group only)
- Dose groups that were examined: all animals during the acclimation period, only high dose and control group animals on day 87 (treatment period) and day 115 (recovery period)

HAEMATOLOGY:
- Time schedule for collection of blood: at the end of the treatment and recovery periods
- Anaesthetic used for blood collection: ether
- Animals fasted: food was withheld overnight prior to blood sampling
- How many animals: all animals
- Parameters examined: erythrocyte count, haematocrit, mean corpuscular volume, red cell volume distribution width, haemoglobin concentration, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, haemoglobin concentration distribution width, prothrombin time, methaemoglobin concentration and leukocyte, neutrophil, eosinophil, basophil, lymphocyte, monocyte, large unstained cells, reticulocyte and thrombocyte counts

CLINICAL CHEMISTRY:
- Time schedule for collection of blood: at the end of the treatment and recovery periods
- Animals fasted: food was withheld overnight prior to blood sampling
- How many animals: all animals
- Parameters examined: glucose, urea, creatinine, total bilirubin, total protein, albumin, globulin, cholesterol, triglycerides, sodium, potassium, calcium, chloride and inorganic phosphorus concentration, and A/G ratio and aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and gamma-glutamyl transpeptidase activity

URINALYSIS:
- Time schedule for collection of urine: at the end of the treatment and recovery periods
- Metabolism cages were used for collection of urine
- Animals fasted: food was withheld overnight prior to blood sampling
- Parameters examined: urine volume, relative density, pH-value, urine colour and protein, glucose, ketone, bilirubin, erythrocyte, leukocyte and urobilinogen content

Sacrifice and pathology:

GROSS PATHOLOGY: Yes

HISTOPATHOLOGY:
The following organs or tissues were examined microscopically:
spleen, mesenteric lymph node, axillary lymph node, femur with joint, bone marrow (femur), trachea, lung, heart, aorta, submandibular salivary gland, liver, pancreas, oesophagus, stomach, small intestine (duodenum, ileum, jejunum), large intestine (caecum, colon, rectum), kidney, urinary bladder, testis, epididymis, uterus, vagina, ovary, adrenal gland, thyroid with parathyroid gland, thymus, peripheral nerve (sciatic nerve), brain (including medulla, pons, cerebral and cerebellar cortex) and any organ with gross lesions.

Other examinations:

ORGAN WEIGHT
The weights of the following organs were determined at necropsy:
brain, heart, liver, kidneys, adrenals, thymus, ovaries or testes, spleen and thyroid

Statistics:

Each treated group was compared to the control group either by Lepage's or Wilcoxon's two-sample test and tested for increasing or decreasing trends from control up to the respective dose group by Jonckheere's test for ordered alternatives.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Food efficiency:

not examined

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

no effects observed

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not specified

Details on results:

CLINICAL SIGNS AND MORTALITY
There were no test item related clinical findings. No deaths occurred.

BODY WEIGHT AND WEIGHT GAIN
Decreased mean body weights were noted from weeks 5 and 8 onwards at 200 mg/kg bw/day in male and female rats, respectively. The mean body weight gains were decreased by the end of the treatment period in animals treated with 200 mg/kg bw/day. During the recovery period, body weight gain in animals previously treated with 200 mg/kg bw/day was higher as compared to controls.

FOOD CONSUMPTION
Food consumption and food consumption ratios were decreased at 200 mg/kg bw/day in both sexes. During the recovery period food intake improved.

WATER CONSUMPTION
The mean water consumption was not influenced by treatment.

HAEMATOLOGY
At the end of the treatment period, a normochromic anaemia with lower erythrocyte count, haemoglobin concentration and haematocrit was observed in males and females at 200 mg/kg bw/day and males at 50 mg/kg bw/day. A higher reticulocyte count associated with higher MCV and MCH values and reduced white blood cell, basophil, lymphocyte and monocyte counts were confined to males at 200 mg/kg bw/day. A higher platelet count was recorded for males at 50 and 200 mg/kg bw/day and a higher prothrombin activity was recorded for males and females at 200 mg/kg bw/day. Evidence of reversibility for all the above parameters was apparent after the recovery period.

CLINICAL CHEMISTRY
Several clinical chemistry parameters including creatinine, urea, protein, globulin, cholesterol and sodium concentration were increased at 50 and/or 200 mg/kg bw/day. Lower potassium levels were noted in males at 200 mg/kg bw/day. All values were similar to the control group values after the 4-week recovery period.

URINALYSIS
Excretion of more acidic red-brown (males) or yellow-brown (females) discoloured urine was observed at 200 mg/kg bw/day. More acidic urine was also excreted by males at 50 mg/kg bw/day. By the end of the recovery period, the colour and pH of the urine excreted by male and females previously treated at 200 mg/kg bw/day was similar to that of control group animals.

ORGAN WEIGHTS
The mean carcass weights were decreased at the end of the treatment period at 200 mg/kg bw/day. Males at 200 mg/kg bw/day showed an elevated mean heart to body weight ratio which still was higher than the concurrent control value at the end of the recovery period.

GROSS PATHOLOGY and HISTOPATHOLOGY
There were no test item related findings.

Effect levels

Key result

Dose descriptor:

NOAEL

Effect level:

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

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: haematology parameters (anaemia) The NOAEL was estimated based on the LOAEL of 50 mg/kg bw/day applying an assessment factor of 5.

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

CHEMICAL ANALYSIS OF DOSE FORMULATIONS

The calculated overall mean contents of the test item in the dose formulations used for the low, mid and high dose groups were 96.9, 104.2 and 101.0 % of the nominal concentrations, respectively (RCC project no. 651688). In a previous 28 -day dose range finding study with the same test item and vehicle, the stability and homogeneity of dose formulations were within the limits of acceptance (RCC project no. 393322).

Estimation of NOAEL:

A more realistic NOAEL was estimated from the LOAEL of 50 mg/kg bw/day applying an assessment factor of 5. This method is applicable and scientifically justified for this test, as only slight adverse effects were observed at 50 mg/kg bw/day (haematology parameters - anaemia). To take the relatively large concentration gap between 5 (clear NOEL) and 50 mg/kg bw/day into account, 5 mg/kg bw/day was not taken as NOAEL, but extrapolated form the LOAEL. The guidance on information requirements and CSA, R.8 (ECHA, 2008 -2010) recommends a factor between 3 and 10 for extrapolation from LOAEL to NOAEL. An assessment factor of 5 seems to be approprate and conservative enough for the current study as only slight effects were observed at the LOAEL of 50 mg/kg bw/day. Consequently a NOAEL of 10 mg/kg bw/day is calculated for this study and used for DNEL and PNEC(oral) derivation.

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study, the NOAEL for FeNa-EDDHA when administered by daily oral gavage for three months was 10 mg/kg bw/day (estimated from the LOAEL).

Executive summary:

In a subchronic toxicity study (Novartis Crop Protection AG, 1998), FeNa-EDDHA in 0.5 % CMC and 0.1 % Tween 80 in distilled water was administered to 10 Sprague-Dawley derived rats/sex/dose level by oral gavage (10 mL/kg bw) at dose levels of 5, 50 or 200 mg/kg bw/day for a period of 90 days. Male and female animals of the concurrent control group were treated with the vehicle only. Additional 10 animals/sex of the high dose and control group were kept on control diet for a 4 -week recovery period before sacrifice. Treatment with the test item resulted in lower food intake and impaired body weight development of rats treated at 200 mg/kg bw/day. Reversible effects on the red blood cell (normochromic anaemia) and white blood cell parameters, and higher values of platelets and prothrombin activity were noted at 50 and/or 200 mg/kg bw/day. In addition, there were changes of blood chemistry and urine parameters concerning the liver and kidneys. The body weight relative heart weight was increased in males at 200 mg/kg bw/day. Under the conditions of this study, the NOAEL for FeNa-EDDHA when administered by daily oral gavage for three months was 10 mg/kg bw/day (estimated from the LOAEL).

This subchronic toxicity study in the rat is acceptable and satisfies the guideline requirement for a subchronic oral study (OECD 408).

Estimation of NOAEL:

A more realistic NOAEL was estimated from the LOAEL of 50 mg/kg bw/day applying an assessment factor of 5. This method is applicable and scientifically justified for this test, as only slight adverse effects were observed at 50 mg/kg bw/day (haematology parameters - anaemia). To take the relatively large concentration gap between 5 (clear NOEL) and 50 mg/kg bw/day into account, 5 mg/kg bw/day was not taken as NOAEL, but extrapolated form the LOAEL. The guidance on information requirements and CSA, R.8 (ECHA, 2008 -2010) recommends a factor between 3 and 10 for extrapolation from LOAEL to NOAEL. An assessment factor of 5 seems to be appropriate and conservative enough for the current study as only slight effects were observed at the LOAEL of 50 mg/kg bw/day. Consequently a NOAEL of 10 mg/kg bw/day is calculated for this study and used for DNEL and PNEC(oral) derivation.