Gastric emptying and absorption of acetylsalicylic acid administered as enteric-coated micro-granules

Enteric-coated and uncoated microgranules of acetylsalicylic acid (ASA), labelled with 51Cr, were administered orally to six healthy male volunteers in a cross-over study. Gastric emptying was studied using a profile scanning radiation technique. Absorption of ASA was followed by measuring the plasma concentration of salicylate. Gastric emptying both of uncoated and enteric-coated granules varied considerably between individuals, but in most cases was gradual and extended over a period of several hours. The median time until 50% and 90% were emptied from the stomach was 1 and 3-3.5 h, respectively, for both the uncoated and enteric-coated granules. The absorption of ASA from the uncoated granules occurred in parallel with the gastric emptying. However, with the enteric-coated granules, absorption was delayed for about 3 h after gastric emptying. It was concluded that the slow absorption of ASA from enteric-coated granules could be explained partly by gradual gastric emptying and partly by slow dissolution of the ASA granules in the intestine.