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Toxicological information

Basic toxicokinetics

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Administrative data

Endpoint:
basic toxicokinetics in vivo
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Reasonably well described inhalation study. No guideline is stated.

Data source

Reference
Reference Type:
publication
Title:
Tierexperimentelle Untersuchung über Ablagerung und Verteilung von Bariumsulfat im Rattenorganismus nach Inhalation
Author:
Einbrodt, H.J. et al.
Year:
1972
Bibliographic source:
Int. Arch. Arbeitsmed. 30: 237 - 244
Report date:
1972

Materials and methods

Objective of study:
distribution
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Over a period of 2 months, rats inhaled 40 mg of barium sulphate/m^3 and were then observed for a period of 4 weeks (post-inhalation phase). Animals were sacrified at 2 week intervals and the barium content of the lungs, lymph nodes, jaw and femur was determined.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Barium sulfate
EC Number:
231-784-4
EC Name:
Barium sulfate
Cas Number:
7727-43-7
Molecular formula:
BaO4S
IUPAC Name:
barium sulfate
Details on test material:
- Name of test material (as cited in study report): Barium sulphate (from Merck)
Particle size distribution: 1 - 2 µm
No further information on the test material was stated.
Radiolabelling:
not specified

Test animals

Species:
rat
Strain:
Wistar
Sex:
female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 180 g
No further information on the test animals was stated.

Administration / exposure

Route of administration:
inhalation: dust
Vehicle:
not specified
Details on exposure:
TYPE OF INHALATION EXPOSURE: whole body

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: A box of 6.5 m^3 in which the rats were held. They were exposed following the Klosterkötter and Einbrodt (1965) procedure.
No further information on details on inhalation exposure was stated.
Duration and frequency of treatment / exposure:
5 days a week for 5 hours daily during a 2 month-period
Doses / concentrations
Remarks:
Doses / Concentrations:
approx. 40 mg/m^3 BaSO4
No. of animals per sex per dose / concentration:
Not stated
Control animals:
not specified
Positive control reference chemical:
Not stated
Details on study design:
The respiratory toilet was determined 20 hours after the first 5 hour exposure. The animals were killed in intervals of 50, 100, 150, and 200 hours of inhalation. Furthermore, animals were killed 14 and 28 days post-exposure. At every sacrification, the lungs, mediastinal lymph nodes, femur, and lower jaw bone of 10 animals were examined for barium content and further animals were examined histologically. The analysis of barium were conducted with the atomic absorption spectrometer Leitz-Unicam.
No further details on study design were stated.
Details on dosing and sampling:
PHARMACOKINETIC STUDY (distribution)
- Tissues and body fluids sampled: lungs, mediastinal lymph nodes, femur, and lower jaw bone
- Time and frequency of sampling: The respiratory toilet was determined 20 hours after the first 5 hour exposure. The animals were killed in intervals of 50, 100, 150, and 200 hours of inhalation. Furthermore, animals were killed 14 and 28 days post-exposure.
No further details on dosing and sampling were stated.
Statistics:
No data

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on distribution in tissues:
No lymph transport worth mentioning took place. In the bone tissue the barium content after initial increase, gradually decresed during the treament. After 2 weeks the barium content in the lungs was high, but over the next 4 weeks it decreased rapidly and then increased again considerably even in the post inhalation period.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): bioaccumulation potential cannot be judged based on study results
No lymph transport worth mentioning took place. In the bone tissue the barium content after initial increase, gradually decreased during the treatment. After 2 weeks the barium content in the lungs was high, but over the next 4 weeks it decreased rapidly and then increased again considerably even in the post inhalation period.