Phosphorodithioic acid, mixed O,O-bis(2-ethylhexyl and iso-Bu and pentyl) esters, zinc salts

Genetic toxicity: in vitro

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study is read-across.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts

EC Number:

283-392-8

EC Name:

Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts

Cas Number:

84605-29-8

Molecular formula:

Not applicable

IUPAC Name:

Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts

Method

Target gene:

Histidine operon (hisG46, hisC3076, hisD3052); Lipopolysaccharide barrier (LPA); DNA excision repar (uvrB)

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

mammalian microsomal enzymes

Test concentrations with justification for top dose:

with s9 mix; 25, 50, 100, 250, 1000, and 5000 ug/plate
without s9 mix: 10, 25, 50, 120, 600, and 3000 ug/plate
Confirmatory assay:
with s9 mix: 100, 250, 500, 1000, 2500 and 5000 ug/plate
without s9 mix: 50, 100, 250, 500, 1000 and 3000 ug/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle:

Controls

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: multiple postive controls (depedning on strain and metabolic activation)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)


DURATION
- Preincubation period:
- Exposure duration: 48 hours
- Expression time (cells in growth medium):
- Selection time (if incubation with a selection agent):
- Fixation time (start of exposure up to fixation or harvest of cells):


SELECTION AGENT (mutation assays):
SPINDLE INHIBITOR (cytogenetic assays):
STAIN (for cytogenetic assays):


NUMBER OF REPLICATIONS:


NUMBER OF CELLS EVALUATED:


DETERMINATION OF CYTOTOXICITY
- Method: growth inhibition


OTHER EXAMINATIONS:
- Determination of polyploidy:
- Determination of endoreplication:
- Other:


OTHER:

Evaluation criteria:

TA98, TA100, WP2uvrA: A postive result must produce at least a 2-fold increase the mean revertants per plate of at least one tester strain over the mean revertants per plate fo the control. A dose response in the mean number of revertants per plate must also occur.
TA1535 and TA1537: A postive result must produce at least a 3-fold increase the mean revertants per plate of at least one tester strain over the mean revertants per plate fo the control. A dose response in the mean number of revertants per plate must also occur.

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:

cytotoxicity

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Test article precipitate was observed on the plates at doses equal to or greater than 3000 ug/plate.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Justification for Read Across from Analogue EC 283-392-8

Common Manufacturing Process:The submission substance (EC 273-527-9) and the analogue (EC 283-392-8) are produced under a common manufacturing process in which a phosphorodithioic acid ester intermediate, (RO)₂PS₂H, is produced by the reaction of phosphorus pentasulfide with an alcohol or a mixture of two alcohols of a similar class - branched alcohol containing C8, C5 and C4 carbons (submission substance) and C3 and C6 carbons (analogue). The intermediate is neutralized with zinc oxide to produce the final multicomponent substance. The reaction is performed in the presence of a highly refined base oil which accounts for 8 – 10.3 % of the final products.

Impurities:The level of impurities in the submission substance and the analogue (data source) is minimal. Impurities have been identified as residual, unreacted alcohols from the production of the phosphorodithioic acid ester intermediates (isobutanol, pentanol and 2-ethylhexanol in the submission substance and isopropyl and 1,3-dimethylbutyl alcohols in the analogue).

Same Chemical Category:The submission substance (EC 273-527-9) and the analogue (EC 283-392-8), generically referred to as ZDDPs, have been shown to have sufficient structural similarities to be included in the Zinc Dialkydithiophosphate Category (ZDDPs) in the United States Environmental Protection Agency High Production Volume (HPV) Chemical Challenge Program.

Structural Similarity:The primary feature accounting for the similarity of the submission substance (EC 273-527-9) and the analogue (EC 283-392-8) is the common organometallic core structure consisting of a central zinc metal bonded to four alkyldithiophosphate esters (ligands) by coordinate covalent bonds -Zn[(S₂P(OR)₂]_2.Structural variations between the submission substance and the analogue are related to the alkyl (R) groups of the alkyldithiophosphate ligands.

The analogue/data source (EC 283-392-8) is a multicomponent mixture of ZDDP monomers and dimers containing isopropyl dithiophosphate ligands, 1,3-dimethylbutyl dithiophosphate ligands and mixtures of isopropyl and 1,3-dimethylbutyl dithiophosphate ligands with a molecular weight range of 492 – 660 (monomer).

The submission substance (EC 273-527-9) is a multicomponent mixture of ZDDP monomers and dimers containing isobutyl dithiophosphate ligands, pentyl dithiophosphate ligands, 2-ethylhexyl dithiophosphates ligands and mixtures of isobutyl, pentyl and 2-ethylhexyl dithiophosphate ligands with a molecular weight range of 548 – 772 (monomer).

Tanimoto Fingerprint (ToxMatch Version 1.06 software) gives a similarity index greater than 0.8 (values range from 0, no similarity to 1, identical). Peer reviewed literature indicates that values greater than 0.6 are significantly similar.DSSTox similarity was 80% between the submission substance and the analogue.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation