D-Gluconic acid, 2,3,4,6-tetrakis-O-(trimethylsilyl)-, .delta.-lactone

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

30 January 2008 - 01 February 2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Guideline:

other: AMES II

Deviations:

not specified

Principles of method if other than guideline:

Principles of method if other than guideline

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(3R,4S,5R,6R)-3,4,5-tris[(trimethylsilyl)oxy]-6-{[(trimethylsilyl)oxy]methyl}oxan-2-one

EC Number:

608-732-8

Cas Number:

32384-65-9

Molecular formula:

C18 H42 O6 Si4

IUPAC Name:

(3R,4S,5R,6R)-3,4,5-tris[(trimethylsilyl)oxy]-6-{[(trimethylsilyl)oxy]methyl}oxan-2-one

Test material form:

liquid

Method

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA 7001, TA 7002, TA 7003, TA 7004, TA 7005, TA 7006, TA 98

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix: rat liver preparation after Aroclor-1254 induction and co-factors

Test concentrations with justification for top dose:

1 to 5000 µg/mL

Vehicle / solvent:

Vehicle(s)/solvent(s) used: DMSO

Controls

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

2-nitrofluorene

other: 2-aminoanthracene (2-AA)

Details on test system and experimental conditions:

The test substance or positive control were incubated with 0.24 mL bacterial overnight culture (ca 107/mL)/exposure medium in 24-well plates for 90 min at 37°C and 250 rpm. With metabolic activation 0.2 mL strain mixture and 0.04 mL S9-mix (30%) were used. After 90 min the exposed cultures were diluted with pH indicator medium lacking histidine and aliquoted into 48 wells of a 384-well plate (3 replicates) using an 8-channel pipette. The plates were incubated for 48 h at 37°C. . Seven concentration levels (1 to 5000 µg/mL) of the test substance were tested along with the appropriate negative and positive controls.

Rationale for test conditions:

The experiment is regarded valid, if the vehicle control showed the normal spontaneous
revertant frequency and the diagnostic mutagens caused the expected increase in the mutation
rate. A concentration-dependent increase of revertant wells (mean of triplicate) over the vehicle
control is indicative for a genotoxic activity of the test substance

Evaluation criteria:

For valid data, the test article was considered to be mutagenic if a concentration-dependent increase of revertant wells (mean of triplicate) over the vehicle control is indicative for a genotoxic activity of the test substance. The test article was considered negative in the assay if the above criteria is not met.
The individual test chemicals were classified according to the following criteria:
Negative: 8/48 wells
Equivocal: 9-12/48 wells
Positive: 13/48 wells

Statistics:

The pH indicator bromocresol purple turns the color of the cultures from blue to yellow as the pH drops due to the accumulation of catabolites from the metabolic activity of revertant cells. The number of positive wells (yellow) out of a total of 48 wells is an indication of the frequency of reversion per replicate per dose and was compared to the number of spontaneous revertant wells of the solvent control. Each test point contains 48 wells of a 384-well plate. In each 48-well section, the wells were scored for the number of revertant wells (yellow) and the mean value of the triplicates was calculated.

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA 7001, TA 7002, TA 7003, TA 7004, TA 7005, TA 7006, TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

No bacteriotoxicity was observed

Vehicle controls validity:

other: DMSO

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

BI 10773 TMS-Lacton (intermediate in the BI 10773 XX synthesis) caused neither basepair
substitution nor frameshift mutations in a series of S. typhimurium tester strains
(TA Mix and TA 98) in the absence and presence of a metabolic activation system when
tested up to recommended and/or insoluble concentrations. Therefore, based on these
results the test substance can be classified as "Ames II negative".