Reaction mass of potassium trifluoroacetate and potassium trifluoromethanesulphinate

Endpoint summary

Description of key information

No data on toxicokinetics, metabolism and distribution are available for the reaction mass of TFSK/TFAK. Based on its high water-solubility, low molecular weight and the effects observed in rats upon subchronic oral exposure, the substance is expected to be well absorbed by the gastro-intestinal.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

No data are available that describe the toxicokinetics of the Reaction mass of TFSK/TFAK, therefore relevant substance properties and data from toxicity studies indicating systemic bioavailability were taken together to assess the general toxicokinetics of the substance.

Physical-chemical properties

The composition of the reaction mass is approximately (50% TFSK / 50% TFAK). However, this product is never found as pure product but as aqueous solution with the following typical composition: 18-20% of TSFK, 18-20 % of TFAK and 60-64 % of water. The Reaction mass of TFSK/TFAK has a water solubility of 314 g/L, an octanol-water partition coefficient (log Kow) of <1 and a negligible vapour pressure. The constituents of the reaction mass have a molecular weight of 172.17 g/mol (TFSK) and 152.1 (TFAK).

Data from acute and repeated dose toxicity studies

Acute toxicity studies

In an acute oral toxicity study, 2000 mg/kg of the reaction mass of TFSK/TFAK were administered by gavage to 6 female rats. Neither clinical signs nor mortality were observed.

An acute dermal toxicity test was carried out with the reaction mass of TFSK/TFAK on rats at 2000 mg/kg in both sexes (5 rats/sex). The test item was applied as supplied as a single dermal 24-hour exposure.No mortality occurred during the study. Neither local dermal signs nor clinical signs were observed. Body weight was normal and necropsy displayed no evidence of any observations at a dose level of 2000 mg/kg bw (active ingredient). A dermal irritation test with the reaction mass of TFSK/TFAK performed in rabbits, did not demonstrate any irritation potential of the test item. The reaction mass of TFSK/TFAK did not induce skin sensitization in the Buehler test.

In the acute inhalation test (4 hours exposure to 5040 mg/m3), no systemic effects were observed in male and female rats.

Subacute and subchronic oral toxicity studies

A combined repeated dose toxicity study with the reproduction/developmental toxicity screening test (OECD 422) was performed with the reaction mass of TFSK and TFAK. The test item was administered orally by gavage once daily at dose levels of 100, 300 and 1000 mg/kg/body weight/day, for approximately 38 days for males and at maximum 57 days for females. No effects were observed on mortality, clinical observations, FOB, food consumption and body weight. The test item administration at 300 and 1000 mg/kg/day active ingredient induced centrilobular hepatocellular hypertrophy. This microscopic change correlated with increased liver weights. This change was not considered to be adverse in view of the absence of associated degenerative microscopic findings or clinical pathology changes in liver enzyme activities.

In the 90-day oral study with Sprague Dawley rats, the reaction mass of TFSK/TFAK was administered daily by oral gavage to male and female rats at 100, 300 and 1000 mg a.i./kg bw/day. The NOAEL for males was considered to be 100 mg/kg, based on marked increase in liver absolute and relative weights and ALP and also decrease in T-Bil at the high and mid dose level . The NOAEL for females was considered to be 300 mg/kg, based on marked increase in liver absolute and relative weights and decrease in T-Bil at the high dose level. The presence of clinical signs during the during the OECD 422 and OECD 408 study show that the test substance is absorbed in the gastrointestinal tract.

Absorption figures used for the DNEL derivation

In the absence of substance specific quantitative data on absorption, 100% absorption is assumed for the inhalation and oral route. As the reaction mass has a molecular weight of <500 (based on the individual constituents), a Log Kow of <1 and a water solubility of 314 g/L, a default dermal absorption figure of 100% should should be selected.