Dibutyltin dilaurate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

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:

March 5-18, 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted in compliance with agreed protocols, with no or minor 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:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

The test substance was stored at ,-20 degrees Celsius, instead of between -16 and -20 degrees celsius. However, it was stated in the test substance information sheet that the storage conditions should be <-18 degrees Celsius, therefore the deviation is c

Principles of method if other than guideline:

No further information required.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

dibutyloxostannane

IUPAC Name:

dibutyloxostannane

Constituent 2

Reference substance name:

di-n-butyltin oxide

IUPAC Name:

di-n-butyltin oxide

Constituent 3

Reference substance name:

Dibutyltin oxide

EC Number:

212-449-1

EC Name:

Dibutyltin oxide

Cas Number:

818-08-6

IUPAC Name:

dibutyl(oxo)stannane

Details on test material:

- Name of test material (as cited in study report): dibutyloxostannane
- Molecular formula (if other than submission substance): C8 H18 OSn
- Molecular weight (if other than submission substance): 248.92
- Structural formula attached as image file (if other than submission substance): see Fig.
- Substance type: white powder
- Analytical purity: 98.09% Dibutyltin oxide
- Composition of test material, percentage of components: 98.09% Dibutyltin oxide, 0.49% di-(i,n)-butyltin oxide, 0.40% monobutyltin oxide, 0.86% tetrabutyldiethyl distannane, 0.17% tributyltin oxide
- Lot/batch No.: 1704
- Expiration date of the lot/batch: October 2003
- Stability under test conditions:
- Storage condition of test material: at <-20 degrees C, in the absence of light
- Other: received 12 October 2003
- Expiry date: October 2003
- Supplier: sent to TNO at the request of ORTEP Asociation Stabilizer Task Force
- TNO Test Substance No.: IMW-01040160B

Method

Target gene:

rfa, uvrB/A,and R-factor

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9 liver homogenate (S9-mix)

Test concentrations with justification for top dose:

Assay 1: 7, 21, 62, 185, 556, 1667, 5000 µg/plate.
Assay 2: 1.25, 2.5, 5, 10, 20 µg/plate

Vehicle / solvent:

Methanol

Controls

Controls 1

Untreated negative controls:

yes

Remarks:

solvent

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

For strain TA1535 and strain TA100 in the absence of the S9-mix

Controls 2

Untreated negative controls:

yes

Remarks:

solvent

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

For strain TA1537 in the absence of the S9-mix

Controls 3

Untreated negative controls:

yes

Remarks:

solvent

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

For strain TA1535, TA98, TA100, and WP 2 uvrA in the presence of the S9-mix

Controls 4

Untreated negative controls:

yes

Remarks:

solvent

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

For strain TA98 in the absence of the S9-mix

Controls 5

Untreated negative controls:

yes

Remarks:

solvent

Positive controls:

yes

Positive control substance:

other: N-ethyl-N-nitrosourea

Remarks:

For strain WP 2 uvrA in the absence of the S9-mix

Controls 6

Untreated negative controls:

yes

Remarks:

solvent

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

For strain TA1537 in the presence of the S9-mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 37 degrees Celsius for 48-72 hours

Evaluation criteria:

The mutagenicity study is considered valid if the mean colony counts of the control values of the strains are within acceptable ranges, if the results of the positive controls meet the criteria for a positive response, and if no more than 5% of the plates are lost through contamination of other unforeseen events.

A test substance is considered to be positive in the bacterial gene mutation test if the mean number of revertant colonies on the test plates is concentration-related increased or if a reproducible two-fold or more increase is observed compared to that on the negative control plates.

A test substance is considered to be negative in the bacterial gene mutation test if it produces neither a dose-related increase in the mean number of revertant colonies nor a reproducivle positive response at any of the test points.

Positive results from the bacterial reverse mutation test indicate that a substance induces point mutations by base substitutions or frameshifts in the genome of either Salmonella typhimurium and/or E. coli. Negative results indicate that under the test conditions, the test substance is not mutagenic in the tested strains.

In case of an inconclusive first assay, a second independant assay was conducted. The first mutagenicity assay is regarded inconclusive if a positive or equivocal response at only one concentrations is observed or if a positive or equivocal responses at several concentrations without a concentration-related increase are observed.

Statistics:

No statistical analysis was performed. Both numerical significance and biological relevance are considered together in the evaluation.

Results and discussion

Test results

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Genotoxic effects: negative both with and without metabolic action.
In both the absence and presence of S9-mix and in all strains, dibutyloxostannane did not cause a more than two-fold or a dose-related increase in the mean number of revertant colonies appearing in the test plates compared to the background spontaneous reversion rate observed with the negative control.

The mean number of his+ and trp+ revertant colonies of the negative controls were within the acceptable range, and the positive controls gave the expected increase in the mean number of revertant colonies.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'. Remarks: all strains

Any other information on results incl. tables

Table 1. Bacterial reverse mutation test with dibutyloxostannane (first assay)
	Average number of revertants per plate
Dose ug/plate	TA 1535		TA1537		TA98		TA 100		E-coli
	without S9	with S9	without S9	with S9	without S9	with S9	without S9	with S9	without S9	with S9
0	25	24	17	12	35	51	168	171	37	40
7	17	17	20	12	34	49	155	169	34	39
21	11	15	5	5	23	29	109	105	26	25
62	0	0	0	0	0	0	0	0	24	13
185	0	0	0	0	0	0	0	0	11	5
556	0	0	0	0	0	0	0	0	0	0
1667	0	0	0	0	0	0	0	0	0	0
5000	0	0	0	0	0	0	0	0	0	0
Positive control	713	525	1220	348	2078	810	886	2013	228	1720

Table 2. Bacterial reverse mutation test with dibutyloxostannane (second assay)
	Average number of revertants per plate
Dose ug/plate	TA 1535		TA1537		TA98		TA 100		E-coli
	without S9	with S9	without S9	with S9	without S9	with S9	without S9	with S9	without S9	with S9
0	26	24	12	15	25	35	153	161	21	27
1.25	19	23	13	14	25	38	174	169	25	26
2.5	11	17	5	9	20	31	142	180	25	26
5	16	21	9	8	23	35	153	174	25	21
10	13	17	6	6	20	35	132	138	21	32
20	10	12	3	4	16	18	95	95	23	22
Positive control	489	428	811	295	1170	965	509	1635	195	1045

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative In both the absence and presence of S9-mix, and in all strains

It is concluded that the results obtained with the test substance in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and in the E. coli strain WP2 uvrA, in both the absence and presence of the S9-mix, indicate that dibutyloxostannane was not mutagenic under the conditions employed in this study.

Executive summary:

Dibutyloxostannane was examined for mutagenic activity in the bacterial reverse mutation test using the histidine-requiring Salmonella typhimurium strains TA 1535, 1537, 98 and 100 and the tryptophan-requiring E. coli strain WP2 uvrA, and a liver fraction of Aroclor 254 -induced rats from metabolic activation (S9 -mix). In both the absence and the presence of S9 -mix and in all strains, dibutyloxostanane did not cause a more than two-fold or a dose-related increase in the mean number of revertant colonies appearing in the test plates compared to the background spontaneous reversion rate observed with the negative control. The mean number of his+ and trp+ revertant colonies of the negative controls were within the acceptable range, and the positive controls gave the expected increase in the mean number of revertant colonies. It is concluded that dibutyloxostannane was not mutagenic under the conditions employed in this study.