Dibutyltin dichloride

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:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Preferred study for this SIDS endpoint.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1979

Report date:

1979

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

Principles of method if other than guideline:

References given:
Ames, B.N., McCann, J. and Yamasake, E. (1975). Methods for detecting carcinogens and mutagens with the Salmonella/ mammalian-microsome muta-genicity test. Mutation Res. 31, 347-364.
McCann, J., Choi, E., Yamasaki, E. and Ames, B.N. (1975). Detection of carcinogens as mutagens in the Salmonella/microsome test: Assay of 300 chemicals. Proc. Nat. Acad. Sci. 72, 5135-5139.
These may have been used as the guidelines for the methods used.

GLP compliance:

no

Remarks:

Pre-dates GLP

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Dibutyltin dichloride

EC Number:

211-670-0

EC Name:

Dibutyltin dichloride

Cas Number:

683-18-1

Molecular formula:

C8H18Cl2Sn

IUPAC Name:

dibutyltin dichloride

Details on test material:

- Name of test material (as cited in study report): Di-n-butylzinndichlorid (dibutyltin dichloride)

Method

Target gene:

Not applicable

Species / strain

Species / strain 1

Species / strain / cell type:

Saccharomyces cerevisiae

Details on mammalian cell type (if applicable):

S9 Homogenate
A 9,000 x g supernatant was prepared from Sprague-Dawley adult male rat liver induced by Aroclor 1254 five days prior to kill according to the procedure of Ames et al.(1975). S9 samples were coded by lot number and assayed for milligrams protein per milliliter and relative P448/P450 activity by methods described in LBI Technical Data on Rat Liver S9 Product.

Additional strain / cell type characteristics:

not specified

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Details on mammalian cell type (if applicable):

S9 Homogenate
A 9,000 x g supernatant was prepared from Sprague-Dawley adult male rat liver induced by Aroclor 1254 five days prior to kill according to the procedure of Ames et al.(1975). S9 samples were coded by lot number and assayed for milligrams protein per milliliter and relative P448/P450 activity by methods described in LBI Technical Data on Rat Liver S9 Product.

Additional strain / cell type characteristics:

not specified

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Details on mammalian cell type (if applicable):

S9 Homogenate
A 9,000 x g supernatant was prepared from Sprague-Dawley adult male rat liver induced by Aroclor 1254 five days prior to kill according to the procedure of Ames et al.(1975). S9 samples were coded by lot number and assayed for milligrams protein per milliliter and relative P448/P450 activity by methods described in LBI Technical Data on Rat Liver S9 Product.

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9

Test concentrations with justification for top dose:

0.5, 1.0, 10.0, 100.0, 500.0 and 1000.0 µg per plate.
After discussion with the Sponsor at LBI, the tests with all of the indicator strains were repeated in the presence and absence of a metabolic activation system because of the toxicity observed at the higher doses.
The test was conducted at four lower doses of 1, 5, 25 and 100 µg per plate.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Ethanol

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: N-methyl, N-nitro, N-nitrosoguanidine; 9-aminoacridine; 2-nitrofluorene and 2-anthramine

Details on test system and experimental conditions:

METHOD OF APPLICATION:
Approximately 10ˆ8 cells from an overnight culture of each indicator strain were added to separate test tubes containing 2.0 ml molten agar supplemented with biotin and a trace of histidine.
For non-activation tests, at least 4 dose levels of the test compound were added to the contents of the appropriate tubes and poured over the surfaces of selective agar plates. In activation tests, at least 4 dose levels of the test chemical were added to the appropriate tubes with cells. Just prior to pouring, an aliquot of reaction mixture (0.5 ml containing the 9,000 x g liver homogenate) was added to each of the activation overlay tubes, which were then mixed, and the contents poured over the surface of a minimal agar plate and allowed to solidify.

DURATION
- Preincubation period: The plates were incubated for 48 hrs at 37°C and scored for the number of colonies growing on each plate. D4 yeast plates were incubated at 30°C for 3-5 days and then scored.
- Exposure duration: 2 days

NUMBER OF REPLICATIONS: nda

NUMBER OF CELLS EVALUATED: nda

DETERMINATION OF CYTOTOXICITY
- Method: nda

Evaluation criteria:

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, 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:

Not reported

Results and discussion

Test results

Species / strain:

other: salmonella typhimurium and saccharomyces cerevisiae

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Not reported

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

The results of the tests conducted on the compound in the absence of a metabolic activation system were all negative.

The results of the tests conducted on the compound in the presence of a rat liver activation system were all negative. The test was repeated with TA-1535 because of the increase in the number of revertants observed at the three lowest dose levels and with TA-1537 and TA-1538 because the solvent control values were unacceptable. The repeat tests were also negative.

After discussion with the Sponsor, the tests with all of the indicator strains were repeated in the presence and absence of a metabolic activation system because of the toxicity observed at the higher doses. The test was conducted at four lower doses of 1, 5, 25 and 100 µg per plate. The compound was toxic at 100 µg to all of the Salmonella strains and slightly toxic to the yeast strain D4. The results were negative.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The test compound, Di-n-butylzinndichlorid did not demonstrate genetic activity in any of the assays conducted in this evaluation and was considered not mutagenic under these test conditions.

Executive summary:

In a Mutagenicity evaluation in the ames salmonella/microsome plate test (LBI project number: 20998), the results of the tests conducted on the test material in the absence of a metabolic activation system were all negative. The results of the tests conducted on the compound in the presence of a rat liver activation system were all negative.

The test material did not demonstrate genetic activity in any of the assays conducted in this evaluation and was considered not mutagenic under these test conditions.