Glycollic acid

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

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:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

yes

Remarks:

S.typhimurium strain TA97a was used as a substitute for the strains TA97 and/or TA1537 normally recommended by EEC and Japan guidelines. THe substitution is acceptable for this design and has no impact on the study validity. The positive control for thi

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: EPA-OPPTS 40 CFR 799.9510

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Glycollic acid

EC Number:

201-180-5

EC Name:

Glycollic acid

Cas Number:

79-14-1

Molecular formula:

C2H4O3

IUPAC Name:

2-hydroxyacetic acid

Details on test material:

Glycolic acid 70% solution

Method

Target gene:

S. typhimurium TA97a- hisD6610, hisO1242.
S. typhimurium TA98- hisD3052.
S. typhimurium TA100- hisG46.
S. typhimurium TA1535- hisG46.
E. coli WP2 uvrA (pKM101)- trpE.

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 97a

Additional strain / cell type characteristics:

other: Histidine mutations: his D6610, his O1242; Additional mutations: rfa uvrB

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 98

Additional strain / cell type characteristics:

other: Histidine mutations: his D3052; Additional mutations: rfa uvrB

Species / strain 3

Species / strain / cell type:

S. typhimurium TA 100

Additional strain / cell type characteristics:

other: Histidine mutations: his G46; Additional mutations: rfa uvrB

Species / strain 4

Species / strain / cell type:

S. typhimurium TA 1535

Additional strain / cell type characteristics:

other: Histidine mutations: his G46; Additional mutations: rfa uvrB R-factor (pKM101 plasmid)

Species / strain 5

Species / strain / cell type:

E. coli WP2 uvr A pKM 101

Additional strain / cell type characteristics:

other: Histidine mutations: trpE; Additional mutations: rfa uvrA R-factor (pKM101 plasmid)

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

Trial 1
S. typhimurium TA100 and E. coli WP2 uvrA (pKM101)- 1, 5, 10, 50, 100, 500, 1000, 2500, 5000 ug/plate.
S. typhimurium TA97a, TA98 and TA1535- 10, 50, 100, 500, 1000, 2500, 5000 ug/plate.

Trial 2 All strains 10, 50, 100, 500, 1000, 2500 and 5000 µg/plate

Vehicle / solvent:

- Test substance solvent/dilutent/negative control: Phosphate buffered saline (PBS.)
- Deionized water was the solvent for NAAZ and ICR 191
- The solvent for 2AA, 2NF, DMBA, and ENNG was dimethyl sulfoxide (DMSO)
- Justification for choice of solvent/vehicle: Based on a solubility test that allowed for the preparation of a soluble or
workable stock concentration up to 50 mg/ml.

Controls

Controls 1

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

9,10-dimethylbenzanthracene

Remarks:

applies for S. typhimurium TA 97a + S9 mix

Controls 2

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

other: ICR 192 acridine mutagen (ICR 191)

Remarks:

applies for S. typhimurium TA 97a - S9 mix

Controls 3

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene (2AA)

Remarks:

applies for S. typhimurium TA 98 + S9 mix

Controls 4

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

applies for S. typhimurium TA 98 - S9 mix

Controls 5

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene (2AA)

Remarks:

applies for S. typhimurium TA 100 + S9 mix

Controls 6

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

applies for S. typhimurium TA 100 - S9 mix

Controls 7

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene (2AA)

Remarks:

applies for S. typhimurium TA 1535 + S9 mix

Controls 8

Untreated negative controls:

yes

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

applies for S. typhimurium TA 1535 - S9 mix

Controls 9

Positive controls:

yes

Positive control substance:

other: 2-Aminoanthracene (2AA)

Remarks:

applies for E. coli WP2 uvr A pKM 101 + S9 mix

Controls 10

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

applies for E. coli WP2 uvr A pKM 101 - S9 mix

Details on test system and experimental conditions:

After pouring top agar onto minimal glucose agar plates and allowing to solidify, the plates were incubated for 48 hours at 37°C.

METHOD OF APPLICATION: In agar (plate incorporation method.)
DURATION
- Preincubation period: over night
- Exposure duration: 48hr
- Selection time (if incubation with a selection agent): 48 hr
SELECTION AGENT (mutation assays): histidine for S. typhimurium, and tryptophan for E. coli
NUMBER OF CELLS EVALUATED: 1x10^8 cells/plate
DETERMINATION OF CYTOTOXICITY
- Evidence of toxicity was scored relative to the concurrent negative control plates. A minimum of three on-toxic
concentration levels was required to classify the test substance. A concentration level was considered non-toxic if it
caused less than 50% reduction in the mean number of revertants per plate relative to the mean of the concurrent negative
control.

Evaluation criteria:

Bacterial lawns were evaluated for evidence of toxicity or test substance precipitation and scored by comparison with concurrent negative control plates. Revertant colonies were counted uing an automatic colony counter for each tester strain unless prohibited by excessive toxicity. Manual counting was employed, as appropriate, if test substance precipitation interfered with automatic counting.
- Positive (or mutagenic) if the mean number of revertants in any strain at any test substance concentration was at least 2
times greater than the mean of the concurrent vehicle control and there was a concentration related increase in the mean
revertants per plate in that same strain.
- Negative (or not mutagenic) if there was no test substance concentration with a mean number of revertants that was at
least 2 times greater than the mean of concurrent vehicle control. Or, if there was no positive concentration related
increase in the mean revertants per plate in that same strain.
- Equivocal if the results not meeting positive or negative criteria classification were evaluated using scientific judgement
and experience and possibly reported as equivocal.

Statistics:

For each strain, the mean number of revertants and the standard deviation were calculated at each concentration, with or without metabolic activation

Data for each tester strain were evaluated independently. For each tester strain, the mean number of revertants and the
standard deviation at each concentration in the presence of and absence of the exogenous metabolic activation system
were calculated.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: yes, ≥ 1000 µg/plate (generally)

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: yes, ≥ 1000 µg/plate (generally)

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: yes, ≥ 1000 µg/plate (generally)

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: yes, ≥ 1000 µg/plate (generally)

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

E. coli WP2 uvr A pKM 101

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

in bacterial background lawns at 500ug/plate or higher in trial 1 without activation and 1000ug/plate or higher in trial 2 without activation, and 2500ug/plate or higher with activation in both trial 1 and 2

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

Under the conditions of this study, no evidence of mutagenic activity was detected in either of two independent trials. Based on these data, the test substance was judged to be negative for mutagenic activity.

Any other information on results incl. tables

Under the conditions of this study, no evidence of mutagenic activity was detected in either of two independent trials. Based on these data, the test substance was judged to be negative for mutagenic activity.

Applicant's summary and conclusion

Conclusions:

Glycolic acid showed no mutagenic effect in any of the bacterial tester strains with and without metabolic activation. Under the conditions of this study, no evidence of mutagenic activity was detected in either of two independent trials. Based on these data, the test substance was judged to be negative for mutagenic activity.

Executive summary:

Glycolic acid showed no mutagenic effect in any of the bacterial tester strains with and without metabolic activation.

Under the conditions of this study, no evidence of mutagenic activity was detected in either of two independent trials. Based on these data, the test substance was judged to be negative for mutagenic activity.