Scintigraphic evaluation of the in vivo performance of dry-coated delayed-release tablets in humans.

In vitro dissolution (A) and in vivo onset of release (B) of delayed release tablet (DR). We characterized the gastrointestinal (GI) transit and drug release characteristics of dry-coated delayed-release tablets under both prandial states in humans using a gamma scintigraphy approach. We also estimated the onset time of drug release from the dry-coated tablets after dissolution of the outer layer in a clinical study, and compared findings with those of in vitro release testing. The dry-coated tablets used in this study were composed of a core containing radiolabeled resin (111-Indium) and a gel forming outer layer made of polyethylene oxide and polyethylene glycol. The dry-coated tablets were administered to human subjects in the fasted and fed state (30 min after ingestion of a standard breakfast radiolabeled with 99m-Technetium). Gastric emptying time, small intestinal transit time, and onset of radioactivity release in the GI tract were estimated from scintigraphic imaging. Release characteristics of the radiolabel from the dry-coated tablets were also assessed in in vitro dissolution testing using a USP apparatus 2 (paddle). Ingestion of food affected the gastric emptying time of the dry-coated tablets but not small intestinal transit. Onset timing of the release of radioactivity from the core of two different formulas of dry-coated tablets was characterized. The onset timing of drug release in the fasted subjects was markedly similar to that in the in vitro dissolution testing at a paddle rate of 200 rpm. [ABSTRACT FROM AUTHOR]