POLYMER-COATED GELATIN CAPSULES AS ORAL DELIVERY DEVICES AND THEIR GASTROINTESTINAL-TRACT BEHAVIOR IN HUMANS

In oral delivery of protein and peptide drugs there is a great need fo r suitable devices for delivering the therapeutic agent-incorporated m icrospheres selectively in the intestine. It is essential that the dru g-loaded multiple unit carrier system should be protected from the har sh environment of the stomach and deliver the carrier system in the la rge intestine where drug action or absorption is desired. Gelatin caps ules were coated with various concentrations of sodium alginate and cr oss-linked with appropriate concentrations of calcium chloride and tes ted in vitro for resistance to gastric and intestinal medium. Gelatin capsules coated with 20% w/v of the polymer which gave the most promis ing result in vitro were evaluated in human volunteers for their in vi vo gastro intestinal tract behaviour. The radiographical studies show that while the uncoated gelatin capsules disintegrated in the stomach within 15 min of ingestion, the alginate coated gelatin capsules remai ned intact as long as they were retained in the stomach (up to 3 h) an d then migrated to the ileocecal region of the intestine and disintegr ated.