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Toxicological information

Basic toxicokinetics

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Administrative data

Endpoint:
basic toxicokinetics in vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Meets generally accepted scientific standards, sufficiently documented, acceptable for assessment.

Data source

Reference
Reference Type:
publication
Title:
Urinary silicon excretion by rats following oral administration of silicon compounds.
Author:
Benke, G.M. and Osborn, T.W.
Year:
1979
Bibliographic source:
Food Cosmet. Toxicol. 27:123-127

Materials and methods

Objective of study:
excretion
Principles of method if other than guideline:
The rate of sodium silicate excretion was obtained from data on urinary excretion in rats after single oral administration of sodium aluminosilicate, Zeolite A, sodium silicate and magnesium trisilicate. Only data for sodium aluminosilicate were described in this entry.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): sodium aluminosilicate, tradename: Zeolex (Huber Corporation)
- Analytical purity: no data
- Other: Huber Corporation specified that this compound met all the purity and quality specifications of the Food Chemicals Codex; the analyses showed that it contained 30 % silicon and 5.4% aluminium.
Radiolabelling:
no

Test animals

Species:
rat
Strain:
other: Sprague Dawley Cox
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Weight at study initiation: 240-260 g
- Diet (e.g. ad libitum): Purina Rat Chow (1500-2000 ppm silicon)
- Water (e.g. ad libitum): tap water; ad libitum
- Acclimation period: 4-5 days

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
not specified
Details on exposure:
PREPARATION OF DOSING SOLUTIONS: All suspensions were prepared in quartz-distilled water which contained < 0.5 ppm silicon and aluminium. Concentrations (w/w) of dosing materials were adjusted so that all groups received the same dosage volume (10 mL/kg). The acutal weights administered were calculated by difference.

Duration and frequency of treatment / exposure:
no data
Doses / concentrations
Remarks:
Doses / Concentrations:
40, 200 and 1000 mg/kg bw
No. of animals per sex per dose:
4
Control animals:
yes
Positive control:
yes, 4 control animals received 10 mL of quartz-distilled water.
Details on dosing and sampling:
PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: urine

- Other:

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on excretion:
At the 40 mg/kg level 12.4 % of administered sodium aluminosilicate was excreted in the urine, elevated levels of Si in the urine were observed only in the first 24 h after oral dosing. At the 200 and the 1000 mg/kg level 5.2 % and 1.3 % of the total administered test substance was excreted in the urine. The urinary excretion half-life for ingested sodium aluminosilicate was calculated to be 38 h. No significant increase in urinary aluminium was detected. Daily urinary aluminium excretion averaged 17.7 ± 3.2 µg for control rats and 15.1 ± 4.3 µg for sodium aluminosilicate treated rats. The excretion rate was independent of the doses applied indicating that the limiting factor is the rate of production of soluble or absorbable silicon in the gastrointestinal tract.

Applicant's summary and conclusion