Silicic acid, aluminum calcium sodium salt

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study was conducted using a guideline similar to OECD Testing Guideline 473, with one ammendment. Limited documentation is available. Read-across from the results on the test substance has been made to the registered substance based on the similar structure of the two substances.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1974

Report date:

1974

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

yes

Remarks:

without external metabolic enzyme system

Principles of method if other than guideline:

Method: Culture technique, determination of cytotoxicity and test for chromosomal aberrations decribed and similar to current guideline
(OECD 473)

GLP compliance:

no

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Silicic acid, aluminum sodium salt

EC Number:

215-684-8

EC Name:

Silicic acid, aluminum sodium salt

Cas Number:

1344-00-9

Details on test material:

FDA-Compound 71-45 ("sodium silicoaluminate")
synthetic silica
Lot no. SR-1621

Method

Species / strain

Species / strain / cell type:

other: Human embryonic lung cells (Wi-38)

Details on mammalian cell type (if applicable):

- Type and identity of media: no data
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: no data
- Periodically "cleansed" against high spontaneous background: no data

Additional strain / cell type characteristics:

not specified

Metabolic activation:

without

Test concentrations with justification for top dose:

1, 10 and 100 µg/ml

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water, 0.85 % saline
- Justification for choice of solvent/vehicle: suspension

Controls

Untreated negative controls:

yes

Remarks:

= vehicle control

Negative solvent / vehicle controls:

yes

Remarks:

saline

Positive controls:

yes

Positive control substance:

triethylenemelamine

Remarks:

Migrated to IUCLID6: 0.1 µg/mL

Details on test system and experimental conditions:

METHOD OF APPLICATION: in suspension, 5 x 10^5 cells/ml
Mutations were quantified by counting anaphase aberrations.

DURATION
- Incubation temperature: 37 °C
- Exposure duration: 24 - 48 h

Fixation: absolute methanol:glacial acetic acid (3:1) for 30 min after centrifugation
STAIN (for cytogenetic assays): acetic acid-orcein stain (2.0 %)

NUMBER OF REPLICATIONS: 3/dose level

NUMBER OF CELLS EVALUATED: 100/dose level

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; other: "any cytopathic effect" at 24, 48, and 72 h after exposure to dose levels logarithmatically spaced (p. 127).


OTHER EXAMINATIONS:
- Determination of polyploidy: yes

Results and discussion

Test results

Species / strain:

other: Human embryonic lung cells (Wi-38)

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: 250 µg/ml (p. 6/7), incipient inhibition of mitosis and cell toxicity as criterion for maximum dose selection

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other: other: Human embryonic lung cells (Wi-38)

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Anaphase aberrations

	Mitotic index^1)	No. of cells	% cells with acentric frag.	% cells with bridges	% multipolar cells	% cells other aberr.^2)	% cells with aberr.
Silene
1.0 µg/ml	5	100	1	0	0	0	1
10 µg/ml	3	100	0	0	0	0	0
100 µg/ml	2	100	1	1	0	0	2
Saline	3	100	2	0	0	0	2
TEM (0.1 µg/ml)	2	100	12	3	0	4 (pp)	19

¹⁾% cells in mitosis: 200 cells observed/dose level

²⁾Cells with polyploidy, pulverisation (pp), or greater than 10 aberrations

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative without metabolic activation

The test substance was found to be negative for genetic toxicity according to the conditions of this study.

Executive summary:

The genetic toxicity of the test substance was determined via use of a guideline similar to the OECD Guideline for Testing of Chemicals 473, with the ammendment from OECD 473 being that no study was conducted in the presence of an external, metabolic activation system. The test was conducted using Human embryonic lung cells (Wi-38) to investigate the occurence of chromosome aberrations in the presence of the test substance. The results were negative in the absence of metabolic activation, therefore the substance is not classified as a genetic toxin. The structure of both silicic acid, aluminium, sodium salt and silicic acid, aluminium, calcium, sodium salt are macromolecular skeletons of silicon and oxygen with the metal cations binding ionically to negatively charged oxygens in the structure. In the silicic acid, aluminium, calcium, sodium salt the metal cations bind ionically to negatively charged oxygens in the structure. The inclusion of calcium salts to the structure of silicic acid, aluminium, sodium salt would not be expected to change the toxicity of the substance.