1997 Volume 50 Issue 4 Pages 287-294
Glucanic acids exist in the form of free acid (GA), anhydride (glucono-δ-lactone: GDL), gluconate salts such as sodium salt (GNA), potassium salt (GK), or calcium salt (GCA). Digestions of various gluconic acids were measured in vitro using human saliva, artificial gastric juice, porcine pancreatin and rat intestinal mucosa. Gluconic acid was stable in these digestive juices, regardless of its form. In an absorption test in situ using ligated loops of rat small intestine, residual gluconic acid in the loops was measured at 30min after injection at a dose of 50mg/kg. While 100% of the gluconate salts remained in the loop, the residual rates of GDL and GA were 45% and 86% respectively. Changes in plasma gluconic acid levels after oral administration of various gluconic acids at a dose of 500mg/kg were investigated in rats. Plasma contents 30min after for administratian of glucanates were only 1.7-2.2μg/ml, whereas those for GDL and GA were 91μg/ ml and 38μg/ml, respectively. In germ-free rats, the residual rates in the digestive tract at 8h after oral administration of GDL, GA and GCA at a dose of 50mg/kg were 25%, 68% and 90%, respectively.
