[Plasma kinetics and elimination of folic acid]

The plasma kinetics and elimination of folic acid were studied in 11 healthy subjects after saturation with a multivitamin preparation. A radioassay was utilized for the determination of folic acid. After the i.m. injection of 1.1 mg folic acid sodium, a maximum plasma level of 63.7 +/- 14.3 nmol/l was reached after 0.69 +/- 0.26 h. The elimination half-life time amounted to 1.53 +/- 0.46 h. Based on the injected amount of folic acid, the cumulative increase in elimination within 24 h amounted to 9.4% +/- 3.1%. Within the first 6 h 81.4% +/- 6.1% of the administered folic acid appeared in the urine and in the following 4 h 17.3% +/- 5.4%.