Localization of Drug Release Sites from an Oral Sustained-Release Formulation of 5-ASA (Pentasa®) in the Gastrointestinal Tract Using Gamma Scintigraphy

Abstract

Release of 5‐ASA from a sustained release formulation (Pentasa®, Ferring A/S, Copenhagen, Denmark) was monitored with plasma sampling for up to 24 hours in nine volunteers under both fasted and fed conditions. Drug absorption was correlated with location of the sustained‐release microgranules in the gastrointestinal tract by gamma scintigraphy. Disintegration of the labeled tablet preparation occurred in the stomach within 20 minutes and acetylated 5‐ASA was detectable in the plasma less than 60 minutes after ingestion. No significant differences were detected in either transit times through the small intestine, peak plasma acetylated 5‐ASA concentration or lag time to absorption between fasted and fed individuals. Peak plasma concentration of acetylated 5‐ASA usually occurred when the microgranules were present in the small intestine or ascending colon. The pharmacoscintigraphic study confirmed that 5‐ASA release from the formulation occurred throughout the gastrointestinal tract, and that food effects on the in vivo behavior of the preparation were minimal.