Abstract
A commercial multivitamin tablet containing 250 mg of vitamin C was daily administered for one week to six healthy adult males aged 20-24 years and the daily plasma concentration and urinary excretion of vitamin C were investigated. There was a significant increase in the plasma concentration and the urinary excretion on the first day, followed by further gradual increases during the week. The initial mean plasma value was 0.35 μg/100 ml indicating marginal vitamin C deficiency, and 0.87 mg/100 ml on the last day, which was a satisfactory level. The mean percentage of urinary vitamin C excretion increased from 24.7% in the first 24 h to 43.6% in the last 24 h after 7 day administration. However, there was considerable individual variation in the urinary vitamin C excretion. The hourly changes in plasma vitamin C concentration were compared between the first and last days of the administration. There was little differences in the plasma concentration-^time profiles except for the lower initial values on the first day. However, T_<max> (time to reach maximal concentration) became shorter, being about 2.8h on the first day and about 2.4h on the last day.
