Oral naproxen formulations

The absorption of naproxen is dependent on the gastric emptying and the dissolution of the drug product in the small intestine. Enteric-coated granules designed to dissolve at pH 5.5 have a delayed absorption profile when given orally. Delivered directly into the duodenum, however, rapid absorption is obtained, indicating that the gastric emptying is the rate-limiting step. By varying the coating layer, it is possible to monitor the dissolution of enteric-coated products within a pH range from 4.5 to 7.0. The onset of absorption can be delayed by increasing the pH resistance of the coating, without affecting the extent of absorption.