after single intravenous injections of 0.1 to 1.0-nmol doses of radioactive folates the urinary clearance based on radioisotope determination was in the sequence : folic acid less than 5-methyltetrahydrofolate ( 5-ch3 thf ) much less than methotrexate .
C0016410
folic acid
C0025677
methotrexate