American Journal of Clinical Nutrition, Vol 9, 324-330, Copyright © 1961 by The American Society for Clinical Nutrition, Inc.

Human Availability Studies of Five Vitamins in Sustained Release Form

¹ From the Research and Development Division, Smith Kline & French Laboratories, and the Department of Microbiology, Hahnemann Medical School, Philadelphia, Pennsylvania

The availability and pattern of absorption of five vitamins, as measured by urinary excretion (thiamine, riboflavin, ascorbic acid, niacin, and pyridoxine) from immediate and sustained release forms, were studied in a crossover experiment with ten healthy human subjects.

Based on a twenty-four-hour urine collection the availabilities of sustained release vitamins were calculated as the following percentages of those from the immediate release formulation: riboflavin, 85.2; pyridoxine, 168.6; thiamine, 155.8; niacin, 90.4; and ascorbic acid, 92.7.

All vitamins except ascorbic acid showed significant sustained release effects when administered in a sustained release formulation and compared with equal amounts of vitamins administered in an immediate release form. Ascorbic acid studies suffered from a lack of adequate saturation of the test subjects with the basal diet used.