Trifluoroacetic acid

Endpoint summary

Description of key information

Trifluoroacetic acid (TFA) is rapidly absorbed by oral route, submitted to enterohepatic circulation, distributed in the body (including the placenta) and excreted in the urine and the bile as parent compound 
Absorption of TFA may occur after skin contact at non corrosive/irritant concentrations.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

Trifluoroacetic acid (TFA) is a dense and fluid liquid, considered as a Volatile Organic Compound (VOC), but also fully miscible in water, where it will exist under its ionised form (see § 4). TFA is not considered as bioaccumulable.

TFA is rapidly absorbed by oral route. Absorption of TFA may occur after skin contact at non corrosive/irritant concentrations, considering both the moderate partition coefficient log Kow (0.79) and its high solubility in the water, together with its molecular mass (114 g/mol). Considered as a VOC, inhalation of TFA vapor may occur at room temperature following by absorption considering the physico-chemical properties described above. After oral exposure, TFA is submitted to enteropatic circulation, then distributed in the body via the blood as ionised form considering its distribution coefficient log D (-0.58) and finally excreted mainly in the urine and in the bile (less extent) as parent compound.

Discussion on bioaccumulation potential result:

Several studies were available which explorated the different endpoint of the toxicokinetics (Weight of evidence approach).

Briefly, the study of Kinoshita et al. (1989) showed that the bile was the major channel of elimination of TFA after an exposure to Halothane by the inhalation route. Furthermore, after an enteral administration of TFA, TFA appeared rapidly in the circulatory blood and a considerable amount of TFA was reabsorbed in the gastrointestinal tract and then excreted into the urine and the bile. Therefore, the most important mechanism of long lasting excretion of TFA after halothane anesthesia seemed to be the enterohepatic circulation of TFA.

In several studies (Ganthous, 1986; Divakaran, 1980; Fraser, 1988; Danielsson, 1984 and Saillenfait, 1996 (see section 7.8.2)) it was demonstrated that TFA passed through the placenta barrier and was therefore found in the amniotic fluid after the exposure to halothane or TFA of the dams by oral or inhalation route. In the case of an halothane exposure, it was highlighted that halothane was mainly metabolised into TFA (the end product of the halothane metabolic pathway) by the maternal metabolic system and then TFA passed throughout the placenta barrier.

Taking into account both the results of the studies and the TFA physico-chemical properties, the following toxicokinetics can be assumed that TFA is rapidly absorbed by oral route. Furthermore, absorption of TFA may occur after skin contact at non corrosive/irritant concentrations, considering both the moderate partition coefficient log Kow (0.79) and its high solubility in the water, together with its molecular mass (114 g/mol). Considered as a VOC (see §4), inhalation of TFA vapor may occur at room temperature following by absorption considering the physico-chemical properties described above. After oral exposure, TFA is :

- submitted to enteropatic circulation,

- distributed in the body via the blood as ionised form considering its distribution coefficient log D (-0.58).

- excreted mainly in the urine and in the bile (less extent) as parent compound.

Discussion on absorption rate:

Absorption of TFA may occur after skin contact at non corrosive/irritant concentrations, considering both the moderate partition coefficient log Kow (0.79) and its high solubility in the water, together with its molecular mass (114 g/mol).