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Description of key information

Key value for chemical safety assessment

Bioaccumulation potential:
low bioaccumulation potential
Absorption rate - oral (%):
93

Additional information

The disposition of 14C-MTHF in rats and mice was determined by following changes in the radioactivity in tissues and excreta with time after dosing. MTHF administered orally at 1, 10 or 100 mg/kg or intravenously at 1 mg/kg to either rats or mice was rapidly metabolised and excreted with <8% (mice) or 8-22% (rats) of the dose remaining in the body after 24 hours (1 and 10 mg/kg doses) or 72 hours (100 mg/kg dose). Based on recovery of radioactivity in excreta (other than faeces) and tissues (other than gastrointestinal tract), absorption of orally administered MTHF was essentially complete (93-100%). There were no overt signs of toxicity observed at any dose. The major route of excretion in mice was in urine followed by exhaled CO2. In rats, the major route of excretion was exhaled CO2 followed by urinary excretion. The excretion of exhaled volatile organic compounds (VOC) was dose-dependent in both species; at lower doses exhaled VOC represented 1-5% of dose, but at the highest dose (100 mg/kg) this proportion rose to 14% (mice) and 27% (rats). Analysis of the VOCs exhaled at the high dose indicated that the increase was due to exhalation of the parent compound. Analysis of urine showed three highly polar peaks in the mouse urine and two polar peaks in the rat urine.