Butylchlorodihydroxystannane

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:

05 December 2001 to 10 December 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Cross-reference

Reason / purpose for cross-reference:

other: read-across target

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted on read-across material

Justification for type of information:

Read across to structurally similar substance monobutyltin trichloride (MBTC, CAS No.: 1118-46-3), see attached justification.

Reason / purpose for cross-reference:

read-across source

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)

Deviations:

not specified

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

N-butyltin trichloride

EC Number:

214-263-6

EC Name:

N-butyltin trichloride

Cas Number:

1118-46-3

Molecular formula:

C4H9Cl3Sn

IUPAC Name:

n-butyltin trichloride

Test material form:

liquid

Details on test material:

- Appearance: straw/brown liquid

Method

Target gene:

Mutation in Genes for Histidine or Tryptophan amino acids:
TA 98: His D3052
TA 100: His G46
TA 1535: His G46
TA 1537: His C3076
WP 2 uvrA: Trp (E. Coli)

Species / strain

Species / strain 1

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not applicable

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

S9 rat liver homogenate (induced with Aroclor)

Test concentrations with justification for top dose:

0, 62, 185, 556, 1667, 5000 µg/plate

Vehicle / solvent:

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

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

benzo(a)pyrene

other: N-ethyl-N-nitrosourea (WP2 uvrA without S9) and 2-aminoanthracene (TA 98, TA 100, TA 1535 and WP2uvrA with S9)

Details on test system and experimental conditions:

SYSTEM OF TESTING
- Metabolic activation system: S9 supernatant of liver homogenate from male Wistar rats treated with Aroclor 1254. One dose of 500 mg/kg bw in soya bean oil (20% w/v) was injected intraperitoneally, and the rats were sacrificed five days later. The livers were homogenised in 0.15 M KCl for 10 minutes at 9,000 g and the supernatant (S9) collected and frozen before storing it at -60°C. 

ADMINISTRATION: 
- Dosing: 62, 185, 556, 1667, 5000 µg/plate
- Number of replicates: 3
-  All plates were incubated at 37 °C for 72 hrs

Evaluation criteria:

The 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 or other unforeseen events.

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

A test material 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 reproducible positive response at any of the test points.

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

Omission of the second assay under these conditions is acceptable as a  single assay does not or hardly results in false negative conclusions. Positive results from the bacterial reverse mutation test indicate that a test material induces point mutations by base substitutions or frameshifts in the genome of either Salmonella typhimurium and/or Escherichia coli. Negative results indicate that under the test conditions, the test material is not mutagenic in the tested strains.

Both numerical significance and biological relevance were considered in the evaluation.

Statistics:

No statistical analysis was performed.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

GENOTOXIC EFFECTS:
- With metabolic activation: Negative.
- Without metabolic activation: Negative.

PRECIPITATION CONCENTRATION: 5000 µg/plate.

CYTOTOXIC CONCENTRATION:
- With metabolic activation: 1667 and 5000 µg/plate for TA 100 and WP2 uvrA. 556, 1667 and 5000 µg/plate for TA 1537.
- Without metabolic activation: 185, 556, 1667 and 5000 µg/plate for TA 100. 1667 and 5000 µg/plate for WP2 uvrA.

- The test material was toxic to the E. coli strain and to TA 100 at the two higher doses (1667 and 5000 µg/plate) in both the absence and presence of S9 mix, and to TA 100 also at 185 and 556 µg/plate in the absence of S9 mix, as was evidenced by a decrease in the mean number of revertant colonies. In addition, the test material was toxic to TA 1537 at 556, 1667 and 5000 µg/plate in the presence of S9 mix.
- In both the presence and the absence of S9 mix and in all strains the test material 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 control were within the acceptable range, and the positive controls gave the expected increase in the mean number of revertant colonies.
- It is concluded that the test material was not mutagenic under the conditions employed in this study.

Any other information on results incl. tables

Table 1: Summary of Experiment

± S9 Mix	Concentration (µg/plate)	Mean number of colonies/plate
		Base-pair Substitution Type			Frameshift Type
		TA100	TA1535	WP2uvrA	TA98	TA1537
-	Solvent 62 185 556 1667 5000	158 138 100 117 69 83	22 21 18 13 19 20	34 26 23 23 21 19	25 19 19 19 21 18	9 13 8 3 6 5
+	Solvent 62 185 556 1667 5000	159 162 131 149 117 95	14 10 16 12 11 12	32 25 26 21 15 16	38 35 31 40 36 30	17 16 15 9 9 8
Positive Controls
-	Name	SA	SA	NENN	2NF	9AA
	Mean no. colonies/plate	598	365	263	760	408
+	Name	2AA	2AA	2AA	2AA	BP
	Mean no. colonies/plate	978	278	758	601	235

9AA = 9-aminoacridine

2AA = 2-aminoanthracene

BP = benzo(a)pyrene

SA = Sodium azide

NENN = N-ethyl-N-nitrosourea

2NF = 2-Nitrofluorene

Applicant's summary and conclusion

Conclusions:

Under the conditions of this study, the test material was not mutagenic in bacterial reverse mutation tests conducted in four strains of Salmonella typhimurium (TA 98, TA 100, TA 1535, TA 1537) and E. coli WP2 uvrA with or without metabolic activation.

Executive summary:

The test material was examined for mutagenic activity in the bacterial reverse mutation test using the histidine-requiring Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, the tryptophan-requiring Escherichia coli strain WP2 uvrA, both in the absence and presence of metabolic activation (S9 mix). The test was performed in accordance with the standardised guidelines OECD 471 and EPA OPPTS 870.5100, under GLP conditions.

Five different concentrations of the test material were used ranging from 62 - 5000 µg/plate. Vehicle and positive controls were run simultaneously.

The test material was toxic to E. coli WP2 uvrA strain and to TA 100 at the two highest doses, 1667 and 5000 ug/plate, in both the absence and presence of S9 mix, and also, to TA 100 at 185 and 556 µg/plate in the absence of S9 mix, evidenced by a decrease in the mean number of revertant colonies. It was also toxic to TA 1537 at 556, 1667, and 5000 µg/plate in the presence of the S9 mix. The test material did not cause a more than 2-fold or a dose-related increase in the mean number of revertant colonies compared to the background spontaneous reversion rate in the negative control. The mean number of his+ and trp+ revertant colonies in the negative controls were within the acceptable range, and the positive controls gave the expected increase in the mean number of revertant colonies.

Under the conditions of this study, the test material was not mutagenic in bacterial reverse mutation tests conducted in four strains of Salmonella typhimurium (TA 98, TA 100, TA 1535, TA 1537) and E. coli WP2 uvrA with or without metabolic activation.