Lithium titanium oxide (Li4Ti5O12)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

No genotoxicity/mutagenicity was detected in the 3 assays performed: bacterial gene mutation, in vitro chromosomal aberration and mammalian cell gene mutation test.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study with GLP.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

Principles of method if other than guideline:

In the first experiment the test was performed according to the "direct plate incorporation method", in the second experiment according to the "preincubation method".

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

other: TA97a

Species / strain / cell type:

S. typhimurium TA 98

Species / strain / cell type:

S. typhimurium TA 100

Species / strain / cell type:

S. typhimurium TA 102

Species / strain / cell type:

S. typhimurium TA 1535

Metabolic activation:

with and without

Metabolic activation system:

S9-mix from Aroclor 1254 induced microsomes of rat liver

Test concentrations with justification for top dose:

62 to 5000 µg/plate with and without S9-mix.

Vehicle / solvent:

Suspension in DMSO.

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene; 7,12-Dimethylbenz[a]anthracene ; 1,8-Dihydroxy-anthraquinone; 2-Nitrofluorene ; Sodium azide; 4-Nitro-o-phenylenediamine; t-Butyl-hydroperoxide.

Details on test system and experimental conditions:

METHOD OF APPLICATION: In the first experiment the test was performed according to the "direct plate incorporation method", in the second experiment according to the "preincubation method".

DURATION
- Preincubation period: 20 min in the preincubation method.
- Exposure duration: 2 days.

NUMBER OF REPLICATIONS: 2 independent experiments. 3 samples per test substance concentration and in the positive control. 6 samples in the negative control.

DETERMINATION OF CYTOTOXICITY
- Method: A reduced bacterial background lawn (mottled instead of homogeneous). Microcolonies of bacteria instead of a homogeneous background lawn. No background lawn. Clearly reduced numbers of revertant colonies.

Evaluation criteria:

The criteria for a positive result are:
A reproducible increase of the number of revertants to more than the following threshold values for at least one of the concentrations:
- For the strains with a low spontaneous revertant rate i.e. TA98 and TA1535: The 2½ fold of the amount of the spontaneous revertants.
- For the strains with a high spontaneous revertant rate i.e. TA97a, TA100 and TA102: The 1.67 fold of the amount of the spontaneous revertants.
These threshold values were derived from the variations in the control samples of the test facility historic data of the Ames test.

Statistics:

Means and standard deviations were calculated.

Species / strain:

S. typhimurium, other: TA 97A, TA 98, TA 100, TA 102, TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Precipitation:
At the 556 µg/plate samples and above a precipitate was visible when the test substance was mixed with the agar. At 5000 and 1667 µg/plate this precipitate was still visible when the colonies were counted but the evaluation of the plates was not impeded.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

Lithium titanium oxide is not mutagenic in the Ames test with the strains of Salmonella typhimurium TA97a, TA98, TA100, TA102 and TA1535 with and without an external metabolising system up to 5000 µg/plate, which is the limit concentration for this kind of test.

Executive summary:

An Ames test with the strains of Salmonella typhimurium TA97a, TA98, TA100, TA102 and TA1535 with and without an external metabolising system up to 5000 µg test substance / plate was performed according to the OECD and EC guidelines.

Lithium titanium oxide was not mutagenic in this Ames test.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

Justification for selection of genetic toxicity endpoint
The different genetic toxicity endpoints investigated would justify the selection of more than one record. Only the system does not provide this possibility. Each of the 3 tests performed were guideline studies under GLP.

Justification for classification or non-classification

No indication was obtained to justify a classification.