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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1979-08
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Only four instead of at least five strains of bacteria were used.
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1979
Report Date:
1979

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
adopted 26 May 1983
Deviations:
yes
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Version / remarks:
Directive 84/449/EEC
Deviations:
yes
Principles of method if other than guideline:
Only four instead of at least five strains of bacteria were used. It has to be mentioned that the test was performed in 1979, the current guideline was adopted in 1997.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- technical pure product (category AC)
- 45-50% (w/w) solution of 2-phosphonobutane-1,2,4-tricarboxylic acid in water
- Pt. 10 E 2806

Method

Target gene:
The Salmonella typhimurium strains are constructed to differentiate between base pair (TA 1535, TA 100) and frameshift (TA 1537, TA 98) mutations. All stains show increased sensitivity due to "deep rough" (one polysaccharide chain is missing, hence, also large molecules can penetrate into the bacteria cells ) and UV-repair-deficiency.
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
NA
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
nominal concentrations: 20; 100; 500; 2500; 12500 µg /plate
Vehicle / solvent:
- DMSO (test substance; Trypaflavin)
- demineralised water (Endoxan)
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
0 µg test substance /plate / demineralised water
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
Substance name: Endoxan; cytostatic agent; the active agent cyclophosphamid is a well-known pro-mutagen; 217. 5 µg equivalent to 150 µg cyclophosphamid; only for strains 1535 and TA 100
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
demineralised water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: Trypaflavin
Remarks:
Active substance of Panflavin and Rivanols; pro-mutagen for frameshift mutations; 200 µg; only for strains 1537 and TA 98
Details on test system and experimental conditions:
Incubation for 48h at 37°C.
4 plates / substance / strain
Negative controls:
4 plates / DMSO / strain
4 plates / demineralised water / stain
Additionally, the total germ account was determined for 2 plates/group.
Evaluation criteria:
A positive result requires a reproducible dose-related duplication of mutants compared with the negative controls for at least one strain.
The colony numbers for negative controls, positive controls and the test plates were determined, the mean values were calculated.

Statistics:
Mean values

Results and discussion

Test results
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:
other: only weak bacteriotoxic effects for concentrations >500 µg/ plate
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'.

Any other information on results incl. tables

No remarks

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

A 45-50% (w/w) solution of 2-phosphonobutane-1,2,4-tricarboxylic acid in water was found to be non-mutagenic under test conditions.
Executive summary:

As there is no data available for tetrasodium hydrogen 2-phosphonatobutane-1,2,4-tricarboxylate a read-across approach with the corresponding parent acid 2-phosphonobutane-1,2,4-tricarboxylic acid is proposed.

In aqueous media, tetrasodium hydrogen 2-phosphonatobutane-tricarboxylate and 2-phosphono-butane-1,2,4-tricarboxylic acid dissociate into the corresponding anion (2-phosphonatobutane-tricarboxylate ion) and the sodium ion and hydrogen ion (proton), respectively. The toxicological properties of 2-phosphonobutane-1,2,4-tricarboxylic acid and its tetrasodium salt are thought to be an effect of the phosphonato-carboxylate ion rather than of the sodium ion or the hydrogen ion (proton), which are normal constituents in body fluids and have no relevant toxic properties in low concentrations.

Therefore a read-across between tetrasodium hydrogen 2-phosphonatobutane-tricarboxylate and 2-phosphono-butane-1,2,4-tricarboxylic acid is justified.

The Ames test was performed with 45-50% (w/w) solution of 2-phosphonobutane-1,2,4-tricarboxylic acid in water, at nominal concentrations of 16; 80; 400; 2500 and 12500 µg /plate. Strain-specific bacteriotoxicity was observed at doses >500 µg/ plate and higher. The reported data of this mutagenicity assay shows, that under the experimental conditions reported, the test item did not induce gene mutations by frameshift or base-pair substitution strains used. Hence, a 45-50% (w/w) solution of 2-phosphonobutane-1,2,4-tricarboxylic acid in water is considered non-mutagenic in this bacterial reverse mutation assay.