Sodium 3-[[(dimethylamino)thioxomethyl]thio]propanesulphonate

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:

10 August - 26 August 1994

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP - Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1994

Report date:

1994

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:

other: EEC Methods for Determination of Toxocity , Annex to Directive 92/69/EEC , Method B14 , Other effects - Mutagenicity : Samonella typhimurium - Reverse Mutation Assay

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: conforms to the USA, EPA (TSCA) guidelines

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

(The Department of Health of the Government of the United Kingdom)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 3-[[(dimethylamino)thioxomethyl]thio]propanesulphonate

EC Number:

242-644-7

EC Name:

Sodium 3-[[(dimethylamino)thioxomethyl]thio]propanesulphonate

Cas Number:

18880-36-9

Molecular formula:

C6H13NO3S3.Na

IUPAC Name:

sodium 3-[(dimethylcarbamothioyl)sulfanyl]propane-1-sulfonate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): DPS ; 1-Propanesulfonic acid , 3-[[(dimethylamino)thioxomethyl]thio] , sodium salt
- Substance type: white powder
- Analytical purity: 90%
- Lot/batch No.: 92002
- Storage condition of test material: room temperature over silica gel

Method

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:

rat liver homogenate metabolising system (10% liver S9 in standard co-factors)

Test concentrations with justification for top dose:

Preliminary toxicity study : 0 , 312.5 , 625 , 1250 , 2500 and 5000 µg/plate
First (Range-Finding study) and second (Main study) experiment : 0 , 8 , 40 , 200 , 1000 and 5000 µg/plate with and without metabolic activation

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: sterile distiiled water
- Justification for choice of solvent/vehicle: the test material was soluble in water up to 50 mg/mL

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

N-ethyl-N-nitro-N-nitrosoguanidine

other: 2-Aminoanthracene

Remarks:

See -Any other information on materials and methods incl. tables- for details

Details on test system and experimental conditions:

METHOD OF APPLICATION : in agar (plate incorporation)

DURATION
- Exposure duration: 48 h

NUMBER OF REPLICATIONS : one preliminary toxicity test in duplicate, mutation assay in triplicate, two independent experiments



DETERMINATION OF CYTOTOXICITY
- Method: Assessment for numbers of revertant colonies and examination for effects on the growth of the bacterial background lawn .

Evaluation criteria:

For a substance to be considered positive in this test system , it should have induced a dose-related and statistically significant increase in mutation rate (of at least twice the spontaneous reversion rate) in one or more strains of bacteria in the presence and/or absence of the S9 microsomal enzymes in both experiments at sub-toxic dose levels .
To be considered negative , the number of induced revertants compared to spontaneous revertants should be less than twofold at each dose level employed , the intervals of which should be between 2 and 5 fold extend to the limits imposed by toxicity or solubility or up to the maximum recommended dose of 5000 µg/plate . In this case the limiting factor was the maximum recommended dose .

Statistics:

A statistical analysis of the data was not required to determine the result of the test.

Results and discussion

Test results

Test results 1

Key result

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:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

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:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

The results of the checks for characteristics , viability and spontaneous reversion rate for each tester strain were all found to be satisfactory .

Any other information on results incl. tables

Table 1 : Range-finding study

		Mean number of revertant colonies per plate (average of 3 plates)
With or without S9 -Mix	Test substance concentration (µg/plate)	Base-pair substitution type			Frameshift type
		TA 100	TA 1535	WP2uvrA^-	TA 98	TA 1537
-	0	117	22	38	24	13
-	8	120	16	35	20	15
-	40	114	23	42	25	13
-	200	117	24	42	22	14
-	1000	113	22	32	17	13
-	5000	124	24	35	21	13
Positive controls , -S9	Name	ENNG	ENNG	ENNG	4NQO	9AA
	Concentrations (µg/plate)	3	5	2	0,2	80
-	Mean No. of colonies/plate (average of 3)	505	175	895	188	338
+	0	154	22	36	35	14
+	8	147	22	37	26	12
+	40	150	28	36	34	12
+	200	132	21	32	27	10
+	1000	135	22	32	26	14
+	5000	150	20	32	28	10
Positive controls , +S9	Name	2AA	2AA	2AA	2AA	2AA
	Concentration (µg/plate)	1	2	10	0,5	2
+	Mean No. of colonies)plate (average of 3)	608	214	168	497	202

ENNG = N-ethyl-N´-nitro-N-nitrosoguanidine

4NQO = 4-nitroquinoline-1 -oxide

9AA = 9-aminoacridine

2AA = 2-aminoanthracene

Table 2 : Main study

		Mean number of revertant colonies per plate (average of 3 plates)
With or without S9 -Mix	Test substance concentration (µg/plate)	Base-pair substitution type			Frameshift type
		TA 100	TA 1535	WP2uvrA^-	TA 98	TA 1537
-	0	106	21	39	30	13
-	312.5	113	17	30	22	13
-	625	102	20	32	21	14
-	1250	103	23	31	24	15
-	2500	107	22	35	19	13
-	5000	107	28	36	22	13
Positive controls , -S9	Name	ENNG	ENNG	ENNG	4NQO	9AA
	Concentrations (µg/plate)	3	5	2	0,2	80
-	Mean No. of colonies/plate (average of 3)	410	161	588	128	456
+	0	114	12	36	38	14
+	312.5	124	13	41	25	15
+	625	113	11	39	30	15
+	1250	109	14	39	35	12
+	2500	120	10	33	28	15
+	5000	119	9	39	31	20
Positive controls , +S9	Name	2AA	2AA	2AA	2AA	2AA
	Concentration (µg/plate)	1	2	10	0,5	2
+	Mean No. of colonies)plate (average of 3)	831	139	185	582	234

ENNG = N-ethyl-N´-nitro-N-nitrosoguanidine

4NQO = 4-nitroquinoline-1 -oxide

9AA = 9-aminoacridine

2AA = 2-aminoanthracene

Applicant's summary and conclusion

Conclusions:

The study was performed according to the OECD TG471 without deviations and therefore considered to be of the highest quality (reliability Klimisch 1). The validity criteria of the test system are fulfilled. No significant increase in the numbers of revertant colonies was recorded for any of the bacterial strains , with any dose of DPS , either with or without metabolic activation. DPS was found to be non-mutagenic under the conditions of this test .

Executive summary:

Salmonella tvphimurium strains TA1535, TA1537, TA98 and TA100 and Escherichia coli strain WP2uvrA^-were treated with DPS by the Ames plate incorporation method at five dose levels, in triplicate both with and without the addition of a rat liver homogenate metabolising system (10% liver S9 in standard co-factors). This method conforms to the guidelines for bacterial mutagenicity testing published by the major Japanese Regulatory Authorities including MITI, MHW, MOL and MAFF. It also meets the requirements of the OECD, EEC and USA, EPA (TSCA) guidelines. The dose range was determined in a preliminary toxicity assay and was 8 to 5000 µg/plate in the first experiment. The experiment was repeated on a separate day using different cultures of the bacterial strains and fresh chemical formulations. In this case the dose range of DPS was 312.5 to 5000 µg/plate. The vehicle (sterile distilled water) control plates gave counts of revertant colonies within the normal range. All positive control chemicals produced marked increases in the numbers of revertant colonies, both with and without the metabolising system. DPS caused no visible reduction in the growth of the bacterial lawn at any dose level either with or without metabolic activation. DPS was therefore tested up to the maximum recommended dose level of 5000 µg/plate. No significant increase in the numbers of revertant colonies was recorded for any of the bacterial strains with any dose of DPS, either with or without metabolic activation. DPS was found to be non-mutagenic under the conditions of this test.