Trichlorooctylstannane

Genetic toxicity: in vitro

Administrative data

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:

October to November 1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted to a method similar to current international protocols, with a few deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1979

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

No E. coli strain used to assess cross linking, solvent control was considered to be mutagenic to TA98 and D4

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Trichlorooctylstannane

EC Number:

221-435-4

EC Name:

Trichlorooctylstannane

Cas Number:

3091-25-6

Molecular formula:

C8H17Cl3Sn

IUPAC Name:

trichlorooctylstannane

Details on test material:

N-Octylzinntrichlorid, Monooctyltin Trichloride [CAS No. 3091-25-6]; clear, colorless liquid, source: Schering AG.

Method

Target gene:

Histidine requirement

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium TA1535, TA1537, TA1538, TA98, TA100; Saccharomyces cerevisiae D4

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

Sprague Dawley adult male rat liver S9 homogenate

Test concentrations with justification for top dose:

0.005, 0.01, 0.1, 1.0, 5.0, 10.0 µl/plate

Vehicle / solvent:

Ethanol

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

Ethanol used as vehicle

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Non-activation: N-methyl, n-nitro, n-nitrosoguanidine (TA-1535, TA-100 and D4), 9-aminoacridine (TA-1537), 2-nitrofluorene (TA-1538 and TA-98); Activation: 2-anthramine for all test systems

Details on test system and experimental conditions:

Ames test: Ames, B.N., J. McCann, and E. Yamasaki.  1975.  Methods for detecting  carcinogens and mutagens with the Salmonella/mammalian-microsome  mutagenicity test.  Mutation Res.  31:347-364.
Salmonella strains were routinely checked for the his, uvrB, rfa, and pKM  101 phenotypes.  Only appropriately screened stock cultures were used for  chemical evaluations.
Ethanol was used to prepare the stock solution and all dilutions of the  test chemical.  
Positive (with and without metabolic activation) and  negative (solvent - ethanol) controls were tested concurrently with the  test substance.
Metabolic Activation: Reaction mixture was prepared with 4 µmol/ml of TPN  (Sodium salt), 5 µmol/ml glucose-6-phosphate, 100 µmol/ml sodium  phosphate (dibasic), 8 µmol/ml MgCl2, 33 µmol/ml KCl, and 0.1 +/- 0.05 ml  S9 Homogenate fraction. The S9 Homogenate was prepared using 9,000 x g supernatant from  Sprague-Dawley adult male rat liver induced by Aroclor 1254 five days  prior to sacrifice (according to the procedure of Ames et al., 1975).  S9  samples were assayed for mg protein/ml and relative P448/P450 activity by  methods described in LBI Technical Data on Rat Liver S9 Product.
Positive controls (without activation): N-methyl-N-nitro-N-nitrosoguanidine (10 µg/plate) for the base-pair  substitution mutants TA1535 and TA100, and S. cerevisia D4. 2-Nitroflourene (10 µg/plate) for the frameshift mutants TA1538 and TA98. 9-Aminoacridine (50 µg/plate) for the frameshift mutant TA1537.
Positive controls (with activation): 2-Anthramine (2.5 µg/plate) for all test strains.
Approximately 1 x 10E8 cells from an overnight culture of each indicator  strain were added to separate test tubes containing 2.0 mL of agar  supplemented with biotin and histidine.  The test without metabolic  activation included 6 dose levels added to the contents of the test tubes  and poured over the agar plates.  In the tests with metabolic activation,  6 dose levels were added to the appropriate test tubes containing an  aliquot (0.5 mL) of the reaction mixture and then poured on the agar  plate.  The plates were incubated for 48 hrs at 37 deg. C and scored for  the number of colonies growing on each plate.  D4 yeast plates were  incubated at 30 deg. C for 3-5 days and then scored.  Positive and  solvent controls were run concurrently with each assay.

Evaluation criteria:

Evaluation Criteria for Ames Assay:
Because the procedures used to evaluate the mutagenicity of the test chemical are semiquantitative, the criteria used to determine positive effects are inherently subjective and are based primarily on a historical data base. Most data sets are evaluated using the following criteria:
1. Strains TA-1535, TA-1537 and TA-1538
If the solvent control value is within the normal range, a chemical that produces a positive dose response over three concentrations with the lowest increase equal to twice the solvent control value is considered to be mutagenic.
2. Strains TA-98, TA-100 and D4
If the solvent control value is within the normal range, a chemical that produces a positive dose response over three concentrations with the highest increase equal to twice the solvent control value for TA-100 and 2-3 times the solvent control value for strains TA-98 and D4 is considered to be
mutagenic. For these strains t the dose-response increase should start at approximately the solvent control value.
3. Pattern
Because TA-1535 and TA-100 are both derived from the same parental strain (G-46) and because TA-1538 and TA-98 are both derived from the same parental strain (D3052), there is a built-in redundancy in the microbial assay. In general, the two strains of a set respond to the same mutagen and such a pattern is sought. It is also anticipated that if a given strain, e.g., TA-1537, responds to a mutagen in nonactivation tests, it will generally do so in activation tests (the converse of this relationship is not expected). While similar response patterns are not required for all mutagens, they can
be used to enhance the reliability of an evaluation decision.
4. Reproducibility
If a chemical produces a response in a single test that cannot be reproduced in one or more additional runs, the initial positive test data lose significance.

Statistics:

No statistical analyses were conducted for this study.  The numbers of  colonies on each plate were counted and recorded.  The data were analyzed  using an unspecified computer program.  The results were presented as  revertants (or convertants for D4) per plate for each strain.  Positive  and solvent controls were provided as reference points.

Results and discussion

Test results

Species / strain:

other: Salmonella typhimurium TA1535, TA1537, TA1538, TA98, TA100; Saccharomyces cerevisiae D4

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Toxicity observed with all strains except TA-98 at the 10 ul dose. Toxicity was also observed at 5 ul/plate with TA-1537, TA-1538 and D4. TA-98 exhibited toxicity at 1, 5, and 10 ul/plate in the activation assay only.

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

The compound was tested for genotoxicity using the Salmonella and  Saccharomyces in vitro assays, with and without the presence of liver  microsomal enzyme preparations from Aroclor-induced rats. The compound was tested at concentrations between 0.005-10 µL/plate.  The  lowest dose did not demonstrate any toxic effect, while the highest dose  showed evidence of some chemically-induced physiological effect.  The  test substance exhibited toxicity with all strains except TA98 at the 10  µL/plate dose level.  Toxicity was also observed at 5 µL/plate with the  strains TA1537, TA1538, and D4.  TA98 also exhibited toxicity at 1, 5,  and 10 µL/plate in the activation assay only.
The results of the mutagenicity tests conducted with octyltin trichloride in both the  absence and presence of a metabolic activation system were negative.
According to the May 1979 revised version of the report, the test with yeast strain D4 was repeated in the presence of S9, because of the increased number of convertants observed in the initial test. The repeat test was negative and the number of convertants observed with various doses of test material were similar to the solvent control values.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The results of the mutagenicity tests conducted with octyltin trichloride in the absence or presence of a metabolic activation system were all negative.

Executive summary:

Octyltin trichloride was examined for mutagenic activity in a series of in vitro microbial assays employing Salmonella and Saccharomyces indicator organisms. The compound was tested directly and in the presence of liver microsomal enzyme preparations from Aroclor-induced rats. The compound was tested over a series of concentrations such that there was either quantitative or qualitative evidence of some chemically-induced physiological effect at the highest dose level. The low dose in all cases was below a concentration that demonstrated any toxic effect. The dose range employed for the evaluation of this compound was from 0.005 ul to 10 ul per plate.

The test compound exhibited toxicity with all the strains except TA-98 at the 10 ul dose 1evel. Toxicity was also observed at 5 ul per plate with the strains TA-1537, TA-1538 and D4. TA-98 exhibited toxicity at 1, 5 and 10 ul per plate in the activation assay only.

The results of the mutagenicity tests conducted with the compound in the absence or presence of a metabolic activation system were all negative.

In conclusion, the test compound, n-octyltin trichloride, did not demonstrate genetic activity in any of the assays conducted in this evaluation and was considered not mutagenic under these test conditions.