Adherence of various oral dosage forms to the esophagus

The potential for various tablets and capsules to adhere to the esophagus or gastrointestinal tract was evaluated in the isolated dog and swine esophagus, using a modification of the procedure of Marvola et al. (1982), in which the swine esophagus was used. The utility of the dog model was demonstrated by showing that comparable adherence values were obtained when the same products were tested in both dog and swine esophagus, and by confirming in the dog model the main findings of Marvola et al. that: (1) force of adherence to the esophagus depends on the type of product, ranking from the greatest to least adherence—hard gelatin capsules, film-coated tablets, uncoated tablets, sugar-coated tablets; (2) for a given product type, adherence increases in proportion to size; and (3) increasing the amount of fluid in the esophagus decreases adherence. The adherence forces of OROS osmotic systems were the lowest of the film-coated products tested. The adherence force of the OROS system lacking an overcoat of hydroxypropyl methyl cellulose (HPMC) was comparable to the negative control salt tablet, while that of the OROS system containing an HPMC overcoat was slightly higher, but still only about one-quarter of that of the commercial gelatin capsules tested. Additionally, the adherence force of the HPMC-coated OROS system was reduced by increasing fluid in the esophagus, simulating the ingestion of a small