1,1,1,2,3,3,3-heptafluoropropane

Endpoint summary

Description of key information

Short description of key information on bioaccumulation potential result: 
The available data indicate that 1,1,1,2,3,3,3-heptafluoropropane is rapidly adsorbed upon inhalation. In rats, it is biotransformed at very low rates to hexafluoroacetone trihydrate (amount in the urine not quantifiable due to very low concentration), following 6 hours inhalation exposure. A study with human volunteers indicated that the substance is rapidly cleared at each exposure concentrations, with the substance concentration in blood below quantifiable limit (0.010 μg/m) at 24 h post-exposure.

Additional information

Biotransformation of 1,1,1,2,3,3,3 -heptafluoropropane (HFC 277ea) was investigated in vivo in rats, by exposing 3 male rats for 6 hours to a sinlge dose of 5000 ppm of the test substance. After the exposure, the urine was collected for 24 hr and analyzed for fluoride content using NMR technique (Koster et al., 1996).

¹⁹F-NMR identified hexafluoroacetone trihydrate in the urine of exposed rats. No significant increase of inorganic fluoride was observed in urinary excretion compared to untreated rats (0-48 hours after the end of the exposure). Because of the very low concentrations of hexafluoroacetone trihydrate present in the collected urine samples, the amount of this metabolite could not be quantified.

Pharmacokinetics of 1,1,1,2,3,3,3 -heptafluoropropane was also investigated in the study with 8 male and female human volunteers, using exposure concentrations 0, 1000, 2000, 4000 and 8000 ppm. Exposure was for 1 h on eight separate occasions, separated generally by 7 days, two air exposures, two exposures to dichlorodifluoromethane (at 1000 and 4000 ppm), and four exposures (at 1000, 2000, 4000 and 8000 ppm) to 1,1,1,2,3,3,3 -heptafluoropropane (Emmen et al., 1999).

The blood concentration-time profile shows that 1,1,1,2,3,3,3-heptafluoropropane was rapidly absorbed at each exposure concentration in both males and females, with a rapid increase and either maximum or near maximum concentration in blood observed after 15 min at each exposure concentrations.

Blood concentrations appeared to be at steady state, with maximum blood concentrations generally measured (52% of the cases) prior to the final sample taken during exposure. The substance was rapidly cleared at each exposure concentration in both males and females. Elimination was predominantly (>83%) biphasic at each exposure level, gender dependent and exposure concentration independent. In the remainder of the population, a single elimination phase was observed.

Following the final exposure at 24-h, blood samples was analyzed for 1,1,1,2,3,3,3-heptafluoropropane. All samples were below the limit of quantification (0.010 μg/ml). Also no metabolites were identified.

The results appear to indicate that the substance is rapidly absorbed upon inhalation, but is also rapidly eliminated, with no traces of substances detected in blood 24 hours after exposure. Available data also appear to suggest that the majority of the substance is excreted unmetabolized. Hexafluoroacetone trihydrate was detected as an only metabolite in the urine of exposed rats; however, its concentration was too low to be quantified.

As the substance is a gas, information on dermal absorption is considered to be irrelevant.