Potassium 1,1,2,2,3,3,4,4,4-nonafluorobutane-1-sulphonate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In vitro genetic toxicity studies have been conducted on PFBS K+. The results of the studies are:

 

Bacterial Reverse Mutation Assay: Negative when tested according to a protocol equivalent to OECD 471.

 

Bacterial Reverse Mutation Assay: Negative when tested according to OECD 471.

 

Chromosome Aberration Test: Negative when tested according to OECD 473.

 

Chromosome Aberration Test: Negative when tested according to OECD 473.

 

The test article did not increase reactive oxygen species or induce DNA damage when incubated with HepG2 cells.

 

An in vivo genetic toxicity study has been conducted on PFBS K+. The result of the study was:

 

Mammalian Erythrocyte Micronucleus Test: Negative when tested according to OECD 474.

 

Additional information

In vitro studies:

 

The mutagenic potential of potassium perfluorobutane sulfonate was evaluated in the Bacterial Reverse Mutation Assay with Salmonella typhimurium strains TA 98, TA 100, TA 1535 and TA 1537 and Escherichia coli strain WP2uvrA in the presence and absence of metabolic activation (S9 mix; Aroclor 1254 -induced rat liver). The study was performed using potassium perfluororbutane sulfonate dissolved in DMSO at concentrations of 50, 100, 500, 1000 and 5000 ug/plate based on a range finding study. The first definitive mutation assay (B-1), using the plate incorporation method, was performed with the four S. typhimurium strains and with E. coli WP2uvrA. Treatment during B-1 was performed by adding either 500 uL deionized, distilled water or 500 uL of rat S-9 cofactor mix to tubes containing 2.0 mL top agar supplemented with 1X histidine-biotin or 1X tryptophan solution. Immediately after, 100 uL of strains TA 98, TA 100, TA 1535, TA 1537 or WP2uvrA were added followed by the appropriate test article dose or solvent. Positive controls were treated with 100 uL of the appropriate stock solution. Tubes were vortexed for 2 -3 seconds after and contents were evenly distributed over a Vogel-Bonner bottom agar plate. Plates were solified on a level surface, inverted, and then incubated at 37C for approximately 70.5 hours. Plates, starting with the highest test article concentration, were observed for the presence of precipitate. Plates with no precipitate were counted using an automatic colony counter (ARTEK Counter, Model 880) and those with precipitate were counted by hand. Three counts were taken by rotating the plate on the counter stage and the mediun count was entered into a validaed, Lotus 123 spreadsheet program. The background lawn was also evaluated. Based on the results of the study, potassium perfluorobutane sulfonate did not result in genotoxicity to Salmonella typhimurium strains TA 98, TA 100, TA 1535 and TA 1537 and Escherichia coli strain WP2uvrA in the presence or absence of exogenous metabolic activation at a dose of 50 -5000 ug/plate.

 

The genotoxic potential of the test article was evaluated using the Bacterial Reverse Mutation Assay with Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 in the presence or absence of exogenous metabolic activation (S9 mix; Aroclor 1254 induced rat liver). The study was performed using the test material dissolved in DMSO at concentrations of 0, 50, 158, 500, 1581, and 5000 ug/plate. The first study was conducted using the plate incorporation with the five S. typhimurium. Three plates were used, both with and without S9 mix, for each strain and dose. Each positive control also contained three plates per strain. The independent repeat was performed as preincubation in a water bath at 37C for 20 minutes. At the end of preincubation, 2 mL of molten soft agar were added to the tubes, mixed, and plated. The same number of plates were used per strain and dose as in the plate incorporation study. Strains were exposed with and without metabolic activation. The mutant count was made after plates had been incubated for 48 hours at 37C. If not interfered colonies were counted automatically using an Artek counter, model 928B. Based on the results of the study, the test article did not result in genotoxicity to Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 in the presence or absence of exogenous metabolic activation at a dose of 50 -5000 ug/plate.

 

The clastogenic potential of the test article was evaluated in a chromosomal aberration assay using Chinese hamster ovary (CHO) cells in the presence and absence of metabolic activation (S9-mix: phenobarbital/β-naphthoflavone-induced rat liver). This study was performed in compliance with GLP (1992), except for the strength and stability of the test article dosing solutions and controls under experimental conditions. The study design was based on OECD 473 draft (1997). The test material was prepared in DMSO prior to the administration to the cells; untreated control was using water was included as well. A dose range-finding test was performed in order to determine appropriate doses for the aberration assay. The aberration assay was performed in two independent experiments. In the definitive assay (B1), the cells were exposed to 500, 1000, 2500 and 5000 ug/mL test article for 3 hours in the presence and absence of S9-mix with an 18-hour fixation time. In the confirmatory assay (B2), the cells were exposed to 50, 100, 500, 1000, 2500 and 5000 ug/mL test article for 18 hours in the absence of S9-mix with an 18-hour fixation time. Positive controls (mitomycin C and cyclophosphamide) were tested in parallel. All dose levels were performed in duplicate. There were no substantial or reproducible dose dependent increases in number of cells with aberrations, relative to the vehicle control under any tested parameters. All criteria for a valid study were met. Based on the results of this study, the test article is not clastogenic in CHO cells in the presence or absence of metabolic activation.

 

The clastogenic potential of the test article was evaluated in a chromosomal aberration assay using Chinese hamster V79 cells in the presence and absence of metabolic activation (S9 mix; Aroclor 1254 induced rat liver). This study was performed in compliance with GLP (1997) and was based on OECD 473 (1997). A pre-test for cytotoxicity was conducted in order to determine dosing for the main study; cytotoxicity was also examined in the main test. In the absence of s9 mix, Chinese hamster V79 cells exposed to concentrations of 1000 µg/mL test material and above after 4 hours and at 1500 µg/mL test material after 18 hours showed relevantly reduced mitotic indices and reduced survival indices when treated for 18 hours. In the main chromosome aberration study, cells were exposed to 0, 500, 1000, and 2000 µg/mL with and without metabolic activation for 4 and 18 hours, respectively.  Fixation times were 18 hours for all groups; an additional group cells were exposed to 2000 µg/mL for 4 hours and harvested at 30 hours. Positive controls (mitomycin C and cyclophosphamide) and solvent controls were tested in parallel. All dose levels were performed in duplicate. There were no substantial or reproducible dose dependent increases in number of cells with aberrations, relative to the vehicle control under any tested parameters. All criteria for a valid study were met.  Based on the results of the study, the test article did not increase the number of cells with aberrations, relative to controls, with and without metabolic activation. The test article is not clastogenic to Chinese hamster V79 cells under the conditions of this study.

 

The aim of the study was to investigate the ability of PFCs to generate reactive oxygen species (ROS) and to induce oxidative DNA damage in the human hepatoma cell line HepG2. HepG2 cells were exposed to PFBS at 0.4 uM to 2000 uM concentrations to determine ROS generation and 100 and 400 uM PFBS to determine if DNA damage was induced. The generation of ROS was measured by the use of dichlorofluorescein as a fluorochrome. The generation of DNA damage was measure with the comet assay as DNA strand breaks (SB) and oxidative damage to purines in terms of formamidopyrimidine-DNA-gycosylase (FPG)-sensitive sites. ROS generation was measured immediately upon exposure to the test article and every 15 minutes thereafter for 3 hours. DNA damage was measured in a separate experiment after 24 hours exposure to the test article. Incubation of human hepatoma HepG2 cells with PFBS up to 2000 uM did not cause an increase in reactive oxygen species (ROS) generation nor did it induce DNA damage.

 

In vivo studies:

 

The genotoxic potential of the test article was evaluated in Harlan Sprague-Dawley rats. Rats (5/sex/group) were administered 0 (vehicle control: Deionized water with 2% Tween 80), 31.3, 62.5, 125, or 250 mg/kg test article via oral gavage for 28 days. Peripheral blood samples were collected from each animal 24 hours after administration of the final dose. Blood samples were examined via flow cytometry to measure the number of micronucleated polychromatic and normochromatic erythrocytes. The micronucleus data were tabulated as the mean frequency of the micronucleated erythrocytes per 1000 cells per animal, plus or minus the standard error of the mean amoung animals within a treatment group.  The frequency of micronucleated cells among Polychromatic erythrocytes (PCE) and Normochromatic erythrocytes (NCE).  Pairwise comparisons were analyzed between each exposure group and control group using an unadjusted one-tailed Pearson X^2 test.  A test was considered positive if the trend test P value was 0.025 or less or the P value for any single exposure group was 0.025/N or less where N is the number of treatment groups.  Trend test P values between 0.025 and 0.05 were considered to be equivocal if accompanied by a monotonic increase in the frequency of micronuclei over the dose range investigated.  All other responses were considered to be negative. Treatment with the test article up to 250 mg/kg/day for 28 days did not induce a statistically significant increase in the frequency of micronucleated erythrocytes per 1000 cells per animal in polychromatic or normochramtic erythrocytes. Based on the results of the study, the test article is negative in the mammalian micronucleus test in male and female rats.

Justification for classification or non-classification

Criteria for classifying the test article as mutagenic are not met.