Thiodiglycol

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions. Restrictions: no details about the purity of the test substance.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

2001

Reference 2

Reference Type:

publication

Title:

Toxicity assessment of thiodiglycol

Author:

Reddy G, Major MA, Leach GJ

Year:

2005

Bibliographic source:

Int J Toxicol 24:435–442

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Principles of method if other than guideline:

adopted 1997

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Thiodiglycol

EC Number:

203-874-3

EC Name:

Thiodiglycol

Cas Number:

111-48-8

Molecular formula:

C4H10O2S

IUPAC Name:

2-[(2-hydroxyethyl)sulfanyl]ethan-1-ol

Details on test material:

Lot No. 05701EQ;
Date received: February 28, 2001
(further data available from the sponsor)

Method

Target gene:

His-
and in E. coli Trp-

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium TA98, TA100, TA1535, TA1537 and E. coli WP2uvrA

Metabolic activation:

with and without

Metabolic activation system:

S9 fraction from liver homogenates of rats (induced with i.p. 500 mg/kg Aroclor 1254) plus cofactors

Test concentrations with justification for top dose:

0, 33, 100, 333, 1000, 3330, 5000 µg/plate

Vehicle / solvent:

water (Quality Biological Lot No. 708589)

Controls

Untreated negative controls:

other: sterility control

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: see freetext

Details on test system and experimental conditions:

Positive control:
with MA: 2.5 µg/plate benzo(a)pyrene for TA98, 2,5 µg/plate 2-aminoanthracene for TA100, TA1535, TA1537 and 25 µg/plate 2-amino-anthracene for WP2uvrA; without MA: 1.0 µg/plate 2-nitrofluorene for TA98, 2 µg/plate sodium azid for TA100 and TA 1535, 2 µg/plate ICR-191 for TA1537, 1 µg/plate 4-nitroquinoline-N-oxide for WP2uvrA.

SYSTEM OF TESTING
- 2 independent trials; in the 1st and 2nd trial the plate incorporation method was used; 3 plates per concentration; S9-mix and dilutions prepared immediately prior to use

- Cytotoxicity:
A preliminary toxicity test was performed to define the concentrations to be used for the mutagenicity study. TA100 and E. coli WP2uvrA exposed to 10 dose levels between 6.67 and 5000 µg/plate with and without MA; cytotoxicity evaluated by scoring the decrease in revertants and/or a thinning or disappearance of the bacterial background lawn (no cytotoxic effects detected); in the main study cytotoxicity scored in the same manner.

Evaluation criteria:

- tester strain integrity and strain culture density demonstrated
- negative and positive controls within the range of historical controls
- positive controls exhibited at least 3-fold increase in revertants over vehicle control
- positive: in TA98, TA100, and WP2uvrA at least 2-fold increase in revertants accompanied by a dose response to increasing concentrations;
- same with TA1535 and TA1537 but increase in revertants at least 3-fold

Statistics:

Means +- standard deviation (SD) calculated

Results and discussion

Test results

Species / strain:

bacteria, other: Salmonella typhimurium TA98, TA100, TA1535, TA1537 and E. coli WP2uvrA

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

Positive controls validity:

valid

Additional information on results:

TEST SUBSTANCE HANDLING
- up to the high dose level the TS formed a transparent colorless solution without precipitates
CYTOTOXICITY IN PRELIMINARY TEST
- no cytotoxic effects detected at any dose level
GENOTOXIC EFFECTS IN THE MAIN STUDY
- thiodiglycol did not induce any significant increase in the number of revertants, with or without S9 mix, in any of the 5 strains tested (see Table below)
- Negative (compared to historical controls) and positive controls were valid .
- no cytotoxicity detected at any dose level

Remarks on result:

other: other:

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Mutagenic activity of thiodiglycol in the Ames test

Mean number of revertants/plate +- standard deviation

Dose level in µg/plate	TA 98	TA 100	TA1535	TA1537	WP2uvrA
	Plate incorporation test I without S9-mix
Range in historical Vehicle controls	6 - 32	57 - 145	3 - 23	1 - 21	6 - 30
0	18+-5	105+-15	14+-5	7+-2	17+-1
33.3	23+-1	95+-18	17+-3	5+-2	20+-4
100	22+-7	107+-18	14+-7	6+-5	22+-4
333	25+-4	85+-7	13+-2	8+-4	21+-3
1000	22+-2	89+-8	12+-3	9+-1	25+-4
3330	22+-5	101+-6	11+-1	6+-3	23+-7
5000	18+-3	89+-8	10+-2	5+-4	23+-5
Positive control	209+-27	1420+-52	1075+-22	864+-16	142+-13
-	Plate incorporation test I with S9-mix
Range in historical Vehicle controls	7 - 48	62 - 164	4 - 27	2 - 26	6 - 48
0	27+-5	127+-9	14+-6	11+-2	19+-5
33.3	31+-3	122+-14	15+-4	10+-2	24+-5
100	31+-3	135+-6	12+-2	14+-3	25+-4
333	23+-4	123+-7	14+-4	12+-3	27+-2
1000	26+-3	119+-9	15+-3	12+-4	24+-3
3330	34+-6	117+-9	23+-9	9+-3	29+-1
5000	24+-6	115+-5	12+-2	8+-2	26+-6
Positive control	297+-12	899+-79	155+-12	100+-7	472+-52
-	Plate incorporation test II without S9-mix
Range in historical Vehicle controls	6 - 32	57 - 145	3 - 23	1 - 21	6 - 30
0	30+-8	110+-5	16+-5	10+-5	26+-9
33.3	33+-6	107+-3	16+-2	11+-3	40+-7
100	30+-4	107+-10	15+-4	9+-1	35+-6
333	37+-8	112+-5	16+-2	13+-6	30+-2
1000	33+-17	105+-6	17+-8	14+-3	29+-4
3330	32+-7	113+-21	16+-9	9+-3	28+-2
5000	33+-10	113+-13	11+-5	11+-4	26+-5
Positive control	297+-37	1557+-66	1257+-27	710+-77	150+-17
-	Standard plate test II with S9-mix
Range in historical Vehicle controls	7 - 48	62 - 164	4 - 27	2 - 26	6 - 48
0	46+-1	127+-14	16+-3	12+-3	23+-5
33.3	56+-10	137+-6	15+-3	17+-5	29+-1
100	50+-4	128+-20	19+-8	17+-5	26+-5
333	54+-5	127+-10	14+-2	17+-6	31+-5
1000	44+-1	131+-14	16+-7	8+-3	26+-2
3330	54+-5	131+-12	18+-5	19+-2	33+-5
5000	54+-3	145+-6	17+-2	10+-6	19+-2
Positive control	420+-33	968+-40	161+-14	123+-8	516+-59

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The test substance did not cause an increase in the mean number of revertants per plate with any of the tester strains in the presence or absence of a metabolic activation system at dose levels up to 5 mg/plate.

Executive summary:

Guideline study with acceptable restrictions (no details about the purity of the TS).

S. typhimurium strains TA98, TA100, TA1535 and TA1537 and E. coli strain WP2uvrA were exposed in the presence and absence of S9 -mix to 33.3, 100, 333, 1000 , 3330 and 5000 μg per plate along with concurrent vehicle and positive controls, using three plates per dose. No increase in revertants was found even at the recommended max. dose of 5000 µg/plate (see OECD 471). No cytotoxic effects were detected. The results of the initial mutagenicity assay were confirmed in an independent 2nd trial.

Conclusion: The test substance did not cause an increase in the mean number of revertants per plate with any of the tester strains in the presence or absence of a metabolic activation system at dose levels up to 5 mg/plate.