Hydrothermal synthesis product of calcium oxide, quartz and water

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1956

Report date:

1956

Reference 2

Reference Type:

other company data

Title:

Unnamed

Year:

1953

Report date:

1953

Materials and methods

Objective of study:

distribution

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline 452 (Chronic Toxicity Studies), oral feed, 24 months

Principles of method if other than guideline:

Determination of Si levels in various organs at termination of a chronic feeding study.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Silicic acid, calcium salt

EC Number:

215-710-8

EC Name:

Silicic acid, calcium salt

Cas Number:

1344-95-2

IUPAC Name:

Silicic acid, Calcium salt

Test material form:

solid

Specific details on test material used for the study:

- Name of test material (as cited in study report) = Silene EF,
- Analytical data after ignition: SiO2 (64 %); CaO (18 %); Al2O3 (0.6 %); MgO (0.1 %); NaCl (1.5 %)

Radiolabelling:

no

Test animals

Species:

rat

Strain:

other: albino (Carworth Farm strain)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: weanling
- Weight at study initiation: averages 70 - 73 g (m, f)
- Fasting period before study: no
- Housing: individual
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS: no data

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: gelatin (15 g/100 mL water)

Details on exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): weekly
- Particular measures: Based on results from the pre-test, the test compound had be administered in moist form
in order to suppress its alkalinity and dustability.
- Mixing appropriate amounts: Appropriate amounts of the Silene-gelatine mixtures were mixed
with the basic diet in a twin-shell blender on w/w basis.
The amount of gelatine added to all diets including controls remained constant
throughout the whole experiment.

- Storage temperature of food: no data

- Dosage regimen: The high-dose groups had accustom to the diet containing higher levels of Silene:
Therefore, gradual increase in Silene content:
7.5 % group: increase from 5 to 7.5 % after 3 wks;
10 % group: increase from 5 to 7.5 % after 3 wks, further increase from 7.5 to 10 % after 10 wks.



VEHICLE
- Justification for use and choice of vehicle (if other than water):
Based on results from the pre-test, the test compound had be administered in moist form
in order to suppress its alkalinity and dustability.
- Concentration in vehicle: variable, depending on the dose


HOMOGENEITY AND STABILITY OF TEST MATERIAL: no data

Duration and frequency of treatment / exposure:

24 months

Doses / concentrations

Remarks:

Doses / Concentrations:
1.0, 5.0, 7.5, and 10 % (w/w) in feed, 7.5 and 10 % after an acclimation period to higher levels (see "Diet Preparation" above)

No. of animals per sex per dose / concentration:

6 m and 6 f of each dose level, tissues of 3 animals of each sex pooled for analysis (2 replicates).

Control animals:

yes, concurrent vehicle

Positive control reference chemical:

none

Details on dosing and sampling:

ANALYSIS of TISSUE Sections (see Report, Table 52)
- silicon dioxide content: upon termination of the experiment:
in kidney, liver, spleen, cardiac muscle, skeletal muscle, and testes:
from 6 m and 6 f of each dose level, tissues of 3 animals of each sex pooled for analysis (2 replicates)

(Method of analysis according to King and Stential: outlined in an interim report that is not available.)

Statistics:

no data, arithmetic means +_S.D.

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:

no data available

Details on distribution in tissues:

After 104 weeks, there was a dose-related increase of Si in the kidney and liver, but not in the other organs examined:
The increase was more marked in males than in females, and much higher in the kidney than in the liver.

Kidney at 5 % level: approx. 3x background (m), no or only slight increase (f)
at 10 % level: approx. 20x background (m), approx. 15x background (f)
Liver at 5 % level: approx. 2x background (m), no or only slight increase (f)
at 10 % level: approx. 3x background (m), approx. 3x background (f)

No time-related organ levels other than 104 weeks have been investigated.

Details on excretion:

no data available

Metabolite characterisation studies

Details on metabolites:

not applicable

Any other information on results incl. tables

Si level in kidneys and livers of rats receiving calcium silicate (Silene EF) in the feed for 104 weeks

(Data adopted from Report, Table 52)

 

Level in diet [%]	Males				Females
	Si as SiO2 [mg/100 g tissue wet weight]				Si as SiO2 [mg/100 g tissue wet weight]
	Kidney		Liver		Kidney		Liver
	Sample*)	average	Sample*)	average	Sample*)	average	Sample*)	average
Control	2.26 0.83	1.54	0.83 1.39	1.11	0.98 2.41	1.69	0.58 1.23	0.91
1.0	2.60 3.49	3.05	0.86 1,10	0.98	2.24 2.29	2.27	2.04 0.49	1.27
5.0	5.45 4.88	5.17	2.96 2.04	2.50	2.79 1.61	2.20	1.37 1.54	1.45
7.5	14.8 11.9	13.35	2.03 2.05	2.04	13.2 7.97	10.58	1.98 3.00	2.49
10.0	41.4 32.4	36.90	3.11 4.07	3.59	24.7 22.7	23.70	3.30 3.22	3.26

*) Sample n = 3 each

No significant differences from the controls can be concluded from Si levels in spleen, heart, skeletal muscle,

and testes (for these organs, data from the report not shown).