Zeolite, silica rich, crystalline, synthetic, non-fibrous

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

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

Adequacy of study:

key study

Study period:

1999-05-05 to 1999-06-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

GLP compliance:

yes

Type of assay:

mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Automatically generated during migration to IUCLID 6, no data available

IUPAC Name:

Automatically generated during migration to IUCLID 6, no data available

Details on test material:

- Name of test material (as cited in study report): Zeostop X
- Related CAS number: 1318-02-1
- Chemical name: silver alumino-silikate
- Analytical purity: approx. 100%
- Lot/batch No.: MR 453 136
- Physical state: white powder
- Composition of test material, percentage of components (surface modified with Ag): Si/Al molarity 1.24
Al2O3: 25.6%
CaO 0.08%
Fe2O3 0.00%
K2O 00.08%
MgO 00.00%
Na2O 11.71%
SiO2 37.33%
Ag2O 02.80%
loss resulting from combustion (900°C)
- Expiry date: May 2000

Method

Target gene:

tk locus

Species / strain

Species / strain / cell type:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Metabolic activation system:

liver post-mitochondrial fraction from rats, induced with Aroclor 1254 (S9)

Test concentrations with justification for top dose:

Exp. 1: without S-9: up to 40 µg/mL ; with S-9: up to 160 µg/mL
Exp. 2: without S-9: up to 25 µg/mL ; with S-9: up to 90 µg/mL
The test article was poorly soluble and undissolved material was observed at aIl concentrations tested.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitroquinoline 1-oxide (without S-9) and benzo(a)pyrene (with S-9)

Details on test system and experimental conditions:

Tissue culture medium: RPMI 1640
In the cytotoxicity range-finding experiment, 15 doses were tested ranging A from 0.3 to 5000 µg/mL. After the three hours treatment incubation period cultures were visually assessed and seven doses ranging from 2.5 to 156 µg/mL were selected for determination of relative survival. The remaining cultures were discarded. The top doses where cells survived treatment were 20 µg/mL in the absence of S-9 (28.53% relative survival) and 156 µg/mL in the presence of S-9 (17.91 % relative survival).
Accordingly, for the first experiment, eight doses (2.5, 5, 10, 20, 25, 30, 35 and 40 µg/mL) were tested in the absence of S-9 and six doses (10, 20, 40, 80, 120 and 160 µg/mL) were tested in the presence of S-9.
For the second experiment, seven doses (5, 10, 15, 17.5, 20 and 25 µg/mL) were tested without S-9 and eight doses (10, 20, 40, 50, 60, 70, 80 and 90 µg/mL) were tested with S-9.

Negative (vehicle) and positive (4-nitroquinoline 1-oxide (without S-9) and benzo(a)pyrene (with S-9)) control treatments were included in each mutation experiment.

Results and discussion

Test results

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

without S-9: above 20 µg/mL; with S-9: above 80 µg/mL

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Mutant frequencies in negative control cultures fell within normal ranges, and clear increases in mutation were induced by the positive control chemicals 4-nitroquinoline 1-oxide (without S-9) and benzo(a)pyrene (with S-9).

In the absence of S-9, no statistically significant increases in mutant frequency were observed following treatment with Zeostop X at any dose level tested, in experiment 1 or 2. In the presence of S-9, in experiment 1, a small but significant increase (1.4 fold), in mutant frequency (136 mutants per 10E6 viable cells [dose], compared to 94 mutants per 10E6 viable cells [control] was observed at the top dose analysed (80 ug/ml). However, 80 µg/ml was a highly toxic dose (10.03 relative survival and 7% relative total growth) and the increase in mutant frequency was related to a depression in day 2 viability counts rather than marked increase in mutant numbers. Furthermore, in experiment 2, when Zeostop X was tested up to doses of similar toxicity, no statistically significant increases in mutant frequency were observed. The small increase in mutant frequency observed in 80 µg/ml was considered to be due to a change event, probably related to the high toxicity observed at this dose, but of no biological significance.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Relative survival in the cytotoxicity range-finding experiment

Treatment (µg/mL)	Relative survival without S-9 (%)	Relative survival with S-9 (%)
0	100	100
2.5	79.18	111.95
5	59.49	113.77
10	63.09	173.17
20	28.53	85.40
39	0	107.79
78	0	51.30
156	0	17.91

Experiment 1:

The three top doses tested in the absence of S-9 (30, 35 and 40 µg/mL) and the top two doses tested in the presence of S-9 (120 and 160 µg/mL) were considered to be too toxic for selection to determine viability and 5-trifluorothymidine (TFT) resistance.

All other doses were selected. The top doses selected were 25 µg/mL in the absence of S-9 (3.08% relative survival [2% RTG]) and 80 µg/mL the presence of S-9 (10.03% relative survival [7 % RTG]).

Experiment 2:

In the second experiment the dose range was modified slightly to take account of toxicity observed in Experiment 1. The top doses selected to determine TFT resistance in this experiment were 22.5 µg/mL in the absence of S-9 (5.33% relative survival [5% RTG]) and 70 µg/mL in the presence of S-9 (9.25% relative survival [3% RTG]).

When tested up to toxic doses, Zeostop X did not induce mutation at the tk locus of L5178Y mouse lymphoma cells in the two independent experiments, with or without S9 mix.

Under the conditions employed in this study, ZEOSTOP X is not mutagenic in this test system.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative