STUDIES OF DELAYED-ACTION MEDICATION. IV. SALICYLATES.

Abstract

Single 1.0 Gm. doses of aspirin were administered as uncoated tablets and as two different enteric‐coated preparations. Enteric coating of aspirin considerably delayed absorption, significant serum levels of salicylate usually not appearing until 6 hours or more. In contrast, absorption from uncoated aspirin tablets was rapid, significant serum salicylate levels being obtained by the first hour and maintained for the next 3 hours, followed by a slow fall. Absorption from the enteric‐coated sodium salicylate preparation studied resembled that from uncoated aspirin, though delayed by about 4 hours. A study of serum salicylate levels during and following four 1.0 Gm. doses of aspirin or sodium salicylate at 4 hour intervals confirmed the considerable delay in obtaining adequate serum levels from the enteric‐coated aspirin preparations. The most consistent daily curve of serum levels was obtained follOWing administration of uncoated tablets. A new tableted preparation of aspirin combined with retarding agents was found to delay absorption of the drug by about one hour without any loss in physiologic availability. If such a preparation should produce less gastric distress on further clinical trial, it might be the preferred preparation where gastric irritation is a problem. Until this is established, aspirin in dissolved form might be the best alternative if uncoated tablets cannot be tolerated because of gastric distress. Enteric‐coated aspirin should not be used in any case where an immediate analgesic or antipyretic effect is desired because of their erratic and often greatly delayed absorption.