Abstract
Six healthy males (20-23 years) ingested vitamin C preparations after breakfast according to a two-period crossover design in each trial. In Trial I, subjects ingested a vitamin C tablet (VC) or a multivitamin tablet (MV), each containing 250mg of vitamin C. No differences in either the plasma concentration-time profiles or the urinary excretion was observed between VC and MV. The peak pleasma vitamin C concentration occured at 3h, and approximately 34% of the dose was excreted into the urine in 24h. In Trial II, subjects ingested a vitamin C tablet or a sustained-release tablet (SR), each containing 500mg of vitamin C. Differences in the plasma concentration-time profiles and the urinary excretion were observed between VC and SR. With VC, the pask plasma vitamin C concentration occured at 3h, and approximately 37% of the does was excreted into the urine in 24h. With SR, the peak plasma vitamin C concentration occured from 6 to 9h, and 3 to 19% of the does was excreted into the urine in 24h, showing great intersubject variability.
