Pentasodium (carboxylatomethyl)iminobis(ethylenenitrilo)tetraacetate

Repeated dose toxicity: other routes

Administrative data

Endpoint:

chronic toxicity: other route

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1976

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published data, information on methods and results is sufficient to make an assessment

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

Toxicological Studies on DTPA

Author:

Planas-Bohne, F.

Year:

1976

Bibliographic source:

Diagn Treat Inc Radionuclides Proc Int Semin 1975 505-515,1976 Tax - Rattus, Heiligenberg

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Method: Other
Repeated dose study in rats using twice weekly intraperitoneal injection of the test material for up to 44 weeks.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Calcium and Zinc salts of DTPA

IUPAC Name:

Calcium and Zinc salts of DTPA

Details on test material:

- Name of test material: Ca DTPA and Zn DTPA

Test animals

Species:

rat

Strain:

other: Heiligenberg

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: not specified
- Age at study initiation: 5 weeks
- Weight at study initiation: no data
- Fasting period before study: no
- Housing: no data
- Diet (e.g. ad libitum): Altromin-R pellets ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

physiological saline

Details on exposure:

Experiment 1 - Groups of 10 male and 10 female Heiligenberg strain rats were injected intraperitoneally twice a week - one with 0.9% saline, one with 100 µmol/kg Ca-DTPA and one with 100 µmol/kg Zn-DTPA for 44 weeks. Six months after the begining of treatment, the animals were mated with untreated rats. During pregnancy the rats did not receive any treatment and during the nursing time they were injected subcutaneously
Experiment 2 - Groups of rats were exposed doses ranging from 0.037 - 5 mmol/kg/day over a period ranging from 5 - 10 days, administered either once daily or in five fractions per day with an interval of 2 hours

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

5 days - 44 weeks

Frequency of treatment:

once daily - twice a week

Doses / concentrations

Remarks:

Doses / Concentrations:
Experiment 1 - 100 µmol/kg Ca-DTPA and 100 µmol/kg Zn-DTPA (The concentration of the stock solutions was 0.4 mmol/ml. The solutions were diluted with 0.9% saline to the concentration required. The injection volume was 1 ml/100 g).
100 µmol/kg Ca-DTPA and 100 µmol/kg Zn-DTPA is equivalent to approximately 40 mg/kg bw/day DTPA acid

Experiment 2 - 0.037 - 5 mmol/kg/day

No. of animals per sex per dose:

Experiment 1 - 10 male + 10 female rats/group
Experiment 2 - no data

Control animals:

not specified

Details on study design:

- Dose selection rationale: no data
- Rationale for animal assignment (if not random): no data

Examinations

Observations and examinations performed and frequency:

Experiment 1 - The body weight was measured every week and the following parameters recorded every six weeks: the packed cell volume , the haemoglobin (Coulter haemoglobinometer), the number of erythrocytes and leucocytes, and the reticulocytes and platelets. For measuring the absorption of 51Cr(III)-EDTA from the intestine, 10 µCi of 51Cr-EDTA per animal were administered by a gastric tube. Immediately afterwards the animals were placed in metabolic cages allowing quantitative separation of urine and faeces. Six months after the begining of treatment, the animals were mated with untreated rats and evaluated on the reproductive capacity (litter size, weight of foetus and resoprtions/dam) and malformations of the litter

Experiment 2 - mortality

Sacrifice and pathology:

Experiment 1 - After 44 weeks the animals were sacrificed and a gross autopsy performed. Bone marrow smears were stained and differentiated. Parts of the kidneys, liver, spleen and small intestine were fixed in Bouin’s solution. After the tissues had been embedded in paraffin, 5 µm sections were stained with haematoxyline-eosin. The rest of the kidneys and liver and 10 cm of the small intestine were used to measure the Zn and Mn concentration. The tissues were digested under pressure at 180°C with 65% HNO3 in special teflon vials and the metal concentration was measured after appropriate dilution with triple-distilled water by atomic absorption spectrophotornetry.
Malformations in the litter were evaluated in the latter part of the experiment

Experiment 2 - The surviving animals were sacrificed at the end of the treatment and packed cell volume, the number of erythrocytes/ µl and the number of thrombocytes per 103 erythrocytes in stained smears were determined

Other examinations:

no data

Statistics:

descriptive statistics

Results and discussion

Results of examinations

Clinical signs:

not specified

Mortality:

not specified

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

not examined

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:

no effects observed

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not specified

Details on results:

Experiment 1:

There were no effects on body weight and weight gain and treatment with either chelates did not have any untoward effects on the hematological and biochemical parameters. The enteral absorption of 51Cr-EDTA not the urinary excretion of hydroxyproline were affected. Gross pathology and histopathology revealed no changes attributable to the treatment. Evaluaion of bone marrow did not reveal any changes. Concentrations of Zn and Mn in kidneys, liver and small intestine were unaffected by treatment with Ca-DTPA or Zn-DTPA

No abnormalities on the reproductive capacity or malformations in litters were observed in either the Ca-DTPA or the Zn-DTPA groups

Experiment 2:

DTPA when administered as a fraction evoked a more drastic response in lethality rather than when administered as repeated injections

Effect levels

1

Dose descriptor:

NOAEL

Remarks:

Ca-DTPA

Effect level:

100 other: micromole/kg bw

Sex:

male/female

Basis for effect level:

other: No effects observed

2

Dose descriptor:

NOAEL

Remarks:

Zn-DTPA

Effect level:

100 other: micro mole/kg bw

Sex:

male/female

Basis for effect level:

other: No effects observed

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

none

Applicant's summary and conclusion

Conclusions:

The results of two experiments are presented and discussed. (I) A 44-week treatment of rats with 100 µmol/kg of both Ca-DTPA and Zn-DTPA twice weekly did not bring about any adverse effects in the treated animals or their offspring. (2) Continuous infusion of Ca-DTPA was shown to be drastically more toxic than repeated injections, whereas Zn-DTPA did not show this dependence on the treatment schedule.