Dipotassium [[N,N'-ethylenebis[N-(carboxylatomethyl)glycinato]](4-)-N,N',O,O',ON,ON']zincate(2-)

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

1980

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

publication

Title:

Early effects of inhaled Ca-DTPA on the rat lung

Author:

Smith VH, Dagle GE, Gelman RA, Ragan HA

Year:

1980

Bibliographic source:

Toxicol Lett 7, 9-16

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Inhalation exposure of rats to Ca-DTPA, 2-4 h/day, 12 times

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

DTPA-CaNa3

IUPAC Name:

DTPA-CaNa3

Constituent 2

Reference substance name:

Calcium trisodium pentetate

EC Number:

235-169-1

EC Name:

Calcium trisodium pentetate

Cas Number:

12111-24-9

Molecular formula:

C14H18CaN3O10.3Na

IUPAC Name:

trisodium 5,8-bis(carboxylatomethyl)-3,13,16-trioxo-2$I3,14$I3,15$I3-trioxa-5,8$I2,11-triaza-1-calcapentacyclo[9.3.3.01.5.01.8.0.1.11]heptadecane-1,1-bis(ylium)-2,14,15-triide

Test material form:

solid - liquid: suspension

Details on test material:

- Name of test material: Calcium trisodium salt of DTPA

Test animals

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hiltop Laboratories
- Weight at study initiation: Approximately 320 gm
- Fasting period before study: None
- Housing: 5/cage
- Diet ( ad libitum): Except during exposure
- Water ( ad libitum):Except during exposure
- Acclimation period:Not specified


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24 °C
- Humidity (%): 40-60 %
- Photoperiod: (12 hrs dark / 12 hrs light):

Administration / exposure

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

whole body

Vehicle:

air

Remarks on MMAD:

MMAD / GSD: See the attachment Table 1

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 60-liter polymethylmethacrylate exposure chamber
- Method of holding animals in test chamber: individual stainless steel mesh cages
- Source and rate of air: not specified
- Method of conditioning air: not specified
- System of generating particulates/aerosols: The aerosols were generated by a nebulizer operated by air at 373 kPa pressure, mproducing chamber concentrations of upto 2 mg Ca-DTPA/L
- Temperature, humidity, pressure in air chamber: not specified
- Air flow rate: not specified
- Air change rate: not specified
- Method of particle size determination: Data for estimating the aerosol size was obtained with a Mercer cascade impactor. Subsequent calculations of MMAD and associated statistics were made by a computer code
- Treatment of exhaust air: not specified

TEST ATMOSPHERE
- Brief description of analytical method used: Aerosol concentrations of Ca-DTPA were continuously sampled by a water bubbler trap operated at a slightly negative pressure relative to the chamber. All air and aerosol flows were set with aid of pressure or vaccum gauges and flowmeters and checked at each exposure with a calibrated wet test meter. DTPA analyses of the cascade impactor stages and the bubbler solutions were made by titration with Zr(IV) using xylenol orange indicator for the DTAP moiety or by AAS for the Ca moiety.
- Samples taken from breathing zone: not specified

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

DTPA analyses of the cascade impactor stages and the bubbler solutions were made by titration with Zr(IV) using xylenol orange indicator for the DTAP moiety or by AAS for the Ca moiety.

Duration of treatment / exposure:

12 daily exposures, necropsy 21 (10 rats/group) or 42 days (remaining 10 rats/group) after last exposure

Frequency of treatment:

2 or 4 h/day for 12 days

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
10 % (2 hrs); 0.42 +/- 0.04 mg/L
Basis:
analytical conc.

Doses / concentrations 2

Remarks:

Doses / Concentrations:
20 % (2 hrs); 0.88 +/- 0.07 mg/L
Basis:
analytical conc.

Doses / concentrations 3

Remarks:

Doses / Concentrations:
40 % (2 hrs); 1.30 +/- 0.14 mg/L
Basis:
analytical conc.

Doses / concentrations 4

Remarks:

Doses / Concentrations:
40 % (4 hrs); 1.18 +/- 0.08 mg/L
Basis:
nominal conc.

No. of animals per sex per dose:

20 rats

Control animals:

yes

Details on study design:

See the attachment Table 1

Positive control:

Not applicable

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
DETAILED CLINICAL OBSERVATIONS: No
BODY WEIGHT: Yes
FOOD CONSUMPTION: No
FOOD EFFICIENCY: No
WATER CONSUMPTION: No
OPHTHALMOSCOPIC EXAMINATION: No
HAEMATOLOGY: Yes
- Time schedule for collection of blood: Prior to death at 42 days
- Anesthetic used for blood collection: Yes, ether
- Parameters checked: number of white and red cells, HB, MCV, MCH, MCHC differential leukocyte count, reticulocytes, platelets
CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: Prior to death at 42 days
- Parameters checked: blood urea nitrogen, serum alkaline phosphatase, serum glutamic oxaloacetic transaminase, glucose and serum proteins
URINALYSIS: No
NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, including lung weight
HISTOPATHOLOGY: Yes

Other examinations:

None

Statistics:

See the attachment

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

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:

not examined

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not examined

Details on results:

One rat exposed to 40% Ca-DTPA died within 48 h after last exposure.
Body weights and lung weights showed no significant differences among the various groups of rats. Hematological parameters and serum chemistry measurements were within normal limits in all animals measured.
Histopathological findings in the lungs of the animals are summarized inTable 2. Pulmonary histiocytosis, a sign of inflammation, was observed in
higher incidence in treated rats than in control rats. After 21 days recovery 39% of the treated animals and 10% of the controls exhibited histiocytosis, (Chi-square = 7.7, P < 0.01), and after 42 days recovery the incidences were 16% and 0%, respectively, (Chi-square = 5.3, P < 0.03). This lesion seemed somewhat more severe in rats exposed to the highest Ca-DTPA doses; however, the lesions were always focal in subpleural perivascular or peribronchiolar regions of the lung parenchyma and included only a small portion of the total lung volume. The histiocytosis appeared to be reversible, since there was a greater incidence in rats killed 21 days following treatment than in those killed at 42 days. In the treated groups reversibility of the histiocytosis was statistically significant (Chi-square = 6.5, P < 0.01), but was less clearly so in the control animals (Chi-square = 3.2, P < 0.08).
There was no difference in the incidence of emphysema at either 21 or 42 days between control and Ca-DTPA-treated groups, nor was there a significant correlation of the occurrence of emphysema and histiocytosis in the same rats.

Effect levels

Dose descriptor:

NOAEL

Effect level:

0.42 mg/L air (analytical)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: The incidence and severity of pulmonary histiocytosis observed in rats exposed to 0.42 mg/L were similar to those observed in the chamber and 0.9% NaCl aerosol control group

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

The estimated amount of Ca-DTPA deposited in the lung and the Ca-DTPA aerosol size parameters are shown in Table I. The Ca-DTPA and NaCI doses were calculated from the measured aerosol concentrations, a minute volume of 0.191/min (estimated for a 320-g rat from data in refs. 14, 15) and retention by the lung of 30% of the inhaled aerosol. The latter value is in the 20-30% retention range quoted by VoIf [16] and is in agreement with the deposition fraction for 1.4 to 2.5-gm MMAD particles in the human lung [17] . In rats 100% of DTPA reaching the deep lung, 15% of that on the nasopharyngeal surfaces, and 30% of that on the trachea is absorbed [5] , as is about 5% of the DTPA swallowed. [18] . Similar values have been reported for the dog [19] . Consequently, one would expect a greater absorbed dose of DTPA than that represented by the lung deposit alone. In eight preliminary experiments in¬volving 4 rats per exposure DTPA measured in urine collected over 24-48 h [20,21], representing > 95% of the absorbed dose [18] , averaged 43% (sx = 7.6%) of the calculated inhaled DTPA. This compares favorably to our as¬sumed 30% deposition in the lung. The inhalation treatment of humans with Ca-DTPA usually involves a 15 to 30-min exposure to aerosols produced from 1 g of Ca-DTPA in the nebulizer solution [1-3,22] with doses estimated at 10 -30% of the aerosol (< 5 mg/kg for a 70 -kg man). Thus, the doses for rats in Table I are roughly 2-9 times those typically encountered by man.

Applicant's summary and conclusion

Conclusions:

It was concluded that multiple inhalation exposures to Ca-DTPA at lung depositions that are 2-9 times the usual human deposition, induced only a mild, focal and reversible pulmonary histiocytosis in the rat. At a level of 0.42 mg/L (420 mg/m3), the incidence and severity of the histiocytosis was comparable to that in the chamber- and aerosol control group; this level, therefore, was considered a NOAEC.

Executive summary:

Inhalation of calcium trisodium diethylenetriaminepentaacetate (Ca-DTPA) increases the removal of plutonium and other transuranics from the body.

Data are required to determine possible biological effects from inhaled DTPA. Female rats were given a single or 12 daily, 2-4-h, inhalation exposures to aerosols of 10, 20 and 40% Ca-DTPA and the lungs were examined at 21 and 42 days following the last exposure. No pulmonary pathology was found from the single inhalation treatment with Ca-DTPA while only a slight, peripheral, histiocytosis was observed in the lungs of multiple-treated rats. There was no significant effect of DTPA treatments on body weight, lung weight, hematology or serum chemistry values.