Registration Dossier

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
Study period:
from 1997-07-03 to 1997-07-24
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
May 1983, revised Draft 1996
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)
Version / remarks:
May 1983, revised Draft 1996
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Version / remarks:
92/69/EEC
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Sodium ascorbyl phosphate
- Physical state: Beige powder
- Analytical purity: 85.4%
- Date of manufacture: 1997-05-02
- Lot/batch No.: 28600/37-9
- Storage condition of test material: Room temperature

Method

Target gene:
The rate of induced back mutations of several bacteria mutants from histidine auxotrophy (his-) to histidine prototrophy (his+) is determined.

Escherichia coli WP2 uvrA which has an AT base pair at the primary reversion site is a derivative of E. coli WP2 with a deficient excision repair and is used to detect substances which induce base pair substitutions. The rate of induced back mutations from tryptophan auxotrophy (trp-) to tryptophan independence (trp+) is determined.
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 fraction
Test concentrations with justification for top dose:
0; 24; 120; 600; 3,000 and 6,000 µ/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: Due to the good solubility of the test substance in water, water was selected as the vehicle.
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
yes
Positive controls:
yes
Remarks:
for TA 135, TA 100, TA 1537, TA 98 with S-9 mix
Positive control substance:
other: 2-aminoanthracene
Positive controls:
yes
Remarks:
for TA 1535, TA 100 and E.coli WP2 uvrA without S9-mix
Positive control substance:
other: N-methyl-N'-nitro-N-nitrosoguanidine
Positive controls:
yes
Remarks:
for TA 98 without S9-mix
Positive control substance:
other: 4-nitro-o-phenylendiamine
Positive controls:
yes
Remarks:
for TA 1537 without S9-mix
Positive control substance:
9-aminoacridine
Positive controls:
yes
Remarks:
for E.coli WP2 uvrA without S9-mix
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION
- Preincubation period: 20 min
- Exposure duration: 48-72 hrs

NUMBER OF REPLICATIONS:
3

DETERMINATION OF CYTOTOXICITY
Method
- decrease in the number of revertants
- clearing or diminution of the background lawn (= reduced his- or trp- background growth)
- reduction in the titer
Evaluation criteria:
The test chemical is considered positive in this assay if the following criteria are met:
- A dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S-9 mix or after adding a metabolizing system.
A test substance is generally considered nonmutagenic in this test if:
The number of revertants for all tester strains were within the historical negative control range under all experimental conditions in two experiments carried out independently of each other.
Statistics:
Determination of Mean and standard deviation

Results and discussion

Test resultsopen allclose all
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
Remarks:
A slight decrease in the number of revertants was occasionally observed depending an the strain and test conditions from about 3,000 µg/plate onward.
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
A slight decrease in the number of revertants was occasionally observed depending an the strain and test conditions from about 3,000 µg/plate onward.
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'. Remarks: S. typh. TA1535,TA1537, TA98, TA100, E.coli WP2uvrA

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Sodium ascorbyl phosphate is not mutagenic.