platinum(IV) nitrate/nitric acid solution

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In an OECD Test Guideline 471 study, to GLP, platinum dinitrate displayed evidence of mutagenicity when tested in four Salmonella typhimurium strains (TA1535, TA1537, TA98 and TA100) and Escherichia coli strain WP2 uvr A, in the presence and absence of a rat liver metabolic activation (S9) system (Thompson, 1999).  

 

In an OECD Test Guideline 476 study, to GLP, platinum dinitrate induced toxicologically significant increases in the mutant frequency at the TK +/- locus in L5178Y cells in two independent experiments, each in the absence and presence of S9. These changes were predominantly caused by small colony formation, representing large genetic changes involving chromosome 11b (Nolan, 2000).

 

No mammalian cell cytogenicity data are available for platinum dinitrate. Albeit limited in its assessment of chromosome effects, the mammalian cell gene mutation study indicates a clastogenic potential of the compound. Further in vitro testing in considered unnecessary in the light of this study and the proposed in vivo genotoxicity testing.

Link to relevant study records

Reference

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:

The study was performed between 29 March 1999 and 17 May 1999.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study (OECD), to GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Target gene:

histidine (Salmonella typhimurium)
tryptophan (Escherichia coli)

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not applicable

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

phenobarbitone/beta-naphthoflavone-induced rat liver S9

Test concentrations with justification for top dose:

Experiment 1: 0, 50, 150, 500, 1500 and 5000 µg/plate
Experiment 2: 0, 50, 150, 500, 1500 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water
- Justification for choice of solvent/vehicle: Well known solvent

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

3 µg/plate for TA100 +S9; 5 µg/plate for TA1535 +S9; 2 µg/plate for WP2uvrA +S9

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

80 µg/plate for TA1537 +S9

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

0.2 µg/plate for TA98 +S9

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

1 µg/plate for TA100 -S9; 2 µg/plate for TA1535 and TA1537 -S9 10 µg/plate for WP2uvrA- -S9

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

Remarks:

5 µg/plate for TA98 -S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)
DURATION
- Exposure duration: 48 hours

Evaluation criteria:

“The test material should have induced a reproducible, dose-related and statistically (Dunnett's method of linear regression) significant increase in the revertant count in at least one strain of bacteria.”

Statistics:

Dunnett's method of linear regression (Kirkland D J (Ed) (1989). Statistical evaluation of mutagenicity test data. UKEMS Sub-committee on Guidelines for Mutagenicity Testing. Report - Part III - Cambridge University Press.)

Species / strain:

S. typhimurium, other:

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Species / strain:

S. typhimurium, other:

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

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

positive

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:

RANGE-FINDING/SCREENING STUDIES: No toxicologically significant cytotoxicity observed at any concentration in any strain, so top concentration for main study set at limit concentration of 5000 µg/plate

COMPARISON WITH HISTORICAL CONTROL DATA:
Vehicle control scores were comparable to historical vehicle controls
Positive control scores were comparable to historical positive controls

OTHER DATA:
“Confirmatory testing in dried dimethyl sulphoxide… verified that the test material would still induce mutagenic increases using a non-aqueous vehicle.”

Remarks on result:

other: strain/cell type: TA100, TA98

Remarks:

Migrated from field 'Test system'.

Conclusions:

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

In an OECD Test Guideline 471 study, to GLP, platinum dinitrate displayed evidence of mutagenicity when tested in four Salmonella typhimurium strains (TA1535, TA1537, TA98 and TA100) and Escherichia coli strain WP2 uvr A, either with or without S9.

Executive summary:

The mutagenic potential of platinum dinitrate was assessed in a reverse mutagenicity assay, conducted according to OECD Test Guideline 471 and to GLP. The test substance was assessed in four Salmonella typhimurium strains (TA1535, TA1537, TA98 and TA100) and in Escherichia coli WP2 uvrA, in an attempt to detect both base-pair substitution and frameshift mutations.

 

Strains were exposed to the test material (each in triplicate) via the plate incorporation method at doses of up to 5000 μg/plate (based on a preliminary assay), both in the absence and presence of amammalian (rat liver) metabolic activation (S9) system. A repeat experiment was conducted.

 

The vehicle and positive controls behaved as expected. Hence, the sensitivity of the assay and the efficacy of the S9-mix were validated. No evidence of cytotoxicity or precipitation was observed at any dose level in either the presence or absence of S9.

 

Dose-related, reproducible and statistically significant increases in revertant colony frequency were observed in S. typhimurium strains TA98 and TA100 and in E. coli both with and without S9. The study authors considered the test material to be mutagenic under the conditions of this test.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (positive)

Genetic toxicity in vivo

Description of key information

No in vivo genotoxicity data were identified.

 

The observation of mutagenic activity in bacterial and mammalian cells (Nolan, 2000; Thompson, 1999) necessitates the consideration of further in vivo testing. Related platinum compounds have also demonstrated a general tendency to induce genotoxicity in vitro, though the available, if somewhat limited, dataset suggests that such findings might not be relevant in vivo and hence a similar lack of classification for mutagenicity is proposed for these compounds. Additional in vivo testing of platinum dinitrate and certain related platinates has been proposed to further elucidate the in vivo relevance of the in vitro findings. The conclusion not to classify platinum dinitrate as a germ cell mutagen should be revisited when the results of the planned in vivo studies are available.

Endpoint conclusion

Endpoint conclusion:

no study available

Mode of Action Analysis / Human Relevance Framework

No data identified.

Additional information

No studies conducted in humans were identified.

 

The mutagenic potential of platinum dinitrate was assessed in a reverse mutagenicity assay, conducted according to OECD Test Guideline 471 and to GLP. The test substance was assessed in four Salmonella typhimurium strains (TA1535, TA1537, TA98 and TA100) and in Escherichia coli WP2 uvrA, in an attempt to detect both base-pair substitution and frameshift mutations. Strains were exposed to the test material (each in triplicate) via the plate incorporation method at doses of up to 5000 μg/plate (based on a preliminary assay), both in the absence and presence of a mammalian (rat liver) metabolic activation (S9) system. A repeat experiment was conducted. The vehicle and positive controls behaved as expected. Hence, the sensitivity of the assay and the efficacy of the S9-mix were validated. No evidence of cytotoxicity or precipitation was observed at any dose level in either the presence or absence of S9. Dose-related, reproducible and statistically significant increases in revertant colony frequency were observed in S. typhimurium strains TA98 and TA100 and in E. coli both with and without S9. The study authors considered the test material to be mutagenic under the conditions of this test (Thompson, 1999).

 

Platinum dinitrate was assessed for its ability to induce mutations at the thymidine kinase locus in an in vitro mouse lymphoma assay conducted in accordance with OECD Test Guideline 476 and to GLP. Mouse lymphoma (L5178Y) cells were exposed to test material for 3 hr in two independent experiments, each in the absence and presence of a mammalian (rat liver) metabolic activation (S9) system. Concentrations of 125-2000 μg/ml were used in both experiments, together with vehicle (solvent) and positive controls. The vehicle (solvent) and positive controls gave acceptable levels of mutant frequencies for the L5178Y cell line at the TK + /- locus, indicating the sensitivity of the test and of the efficacy of the metabolising system. The test compound induced statistically significant increases in mutant frequency, both with and without S9, in both experiments and was considered to be mutagenic to L5178Y cells under the conditions of the test. The increase in mutant frequency was predominantly due to small colony formation (corresponding to large genetic changes involving chromosome 11b) and is thus indicative of potential clastogenic activity (Nolan, 2000).

 

No in vivo genotoxicity data were identified.

 

Several Expert Groups have assessed the toxicity profile of platinum, and various platinum compounds, including the assessment of CMR properties. All reviews have indicated that platinum compounds have been reported to be mutagenic in a range of in vitro studies (DECOS, 2008; EMA, 2008; SCOEL, 2011; WHO, 1991). Cisplatin and related compounds are known DNA-reactive carcinogens and, as these compounds are better investigated due to their pharmaceutical properties, this has been confirmed in vivo. As cisplatin-type substances differ in chemical reactivity (liability of ligands, number of active sites etc.) it is reasonable to expect that not all forms of platinum are carcinogenic (DECOS, 2008). Limited experimental data on carcinogenicity for other platinum compounds give no evidence of activity that would meet classification criteria (DECOS, 2008; SCOEL, 2011).

 

Despite the generally positive in vitro results identified for the platinum compounds in various bacterial/mammalian cell mutagenicity assays (supported by some mammalian cell cytogenicity tests), the in vivo relevance of these in vitro findings remains unclear. Indeed, the available in vivo data returned mostly negative results. However, some of the identified studies might not be considered sufficiently robust (according to ECHA standards) to override the in vitro mutagenicity findings (e.g. a sex-linked recessive lethal test in Drosophila melanogaster (OECD TG 477, performed with dipotassium tetrachloroplatinate) and a liver unscheduled DNA synthesis assay (OECD TG 486, performed with tetraammineplatinum hydrogen carbonate)). Indeed, further in vivo testing of certain platinum compounds has been proposed to further elucidate the in vivo relevance of the in vitro findings.

 

References

EMA (2008). European Medicines Agency. Guideline on the specification limits for residues of metal catalysts or metal reagents. Committee for Medicinal Products for Human Use (CHMP). EMEA/CHMP/SWP/4446/2000. http://www.ema.europa.eu/docs/en_GB/document_library/Scientific_guideline/2009/09/WC500003586.pdf

HCN (2008). Health Council of the Netherlands (DECOS). Platinum and platinum compounds. Health based recommended occupational exposure limit. https://www.gezondheidsraad.nl/sites/default/files/200812OSH_1.pdf 

SCOEL (2011). Recommendation from the Scientific Committee on Occupational Exposure Limits for platinum and platinum compounds. SCOEL/SUM/150. http://ec.europa.eu/social/BlobServlet?docId=7303&langId=en

 

WHO (1991). World Health Organization. Platinum. International Programme on Chemical Safety. Environmental Health Criteria 125. http://www.inchem.org/documents/ehc/ehc/ehc125.htm#SectionNumber:7.4

Justification for classification or non-classification

Based on the existing data set, platinum dinitrate does not currently meet the criteria for classification as a germ cell mutagen (category 1A or 1B) under EU CLP criteria (EC 1272/2008). However, this conclusion should be revisited when the results of the planned in vivo studies are available.