In general, uncoated tablets are absorbed extensively in the proximal ( beginning )portion of the GI tract; therefore,
delayed-
release tablets are used to achieve a local effect in the colon. Following oral administration, 20—30% of a dose is absorbed, with peak plasma concentrations achieved in 3—12 hours. It is specially formulated to release the medicine after it has passed through your stomach into your intestines. If you are finding only the shell that is very common.