An oral drug delivery system comprising a coated tablet having one or more surfaces. The coated tablet further comprises a core and a coating surrounding the core. The core comprises an active ingredient composition comprising at least one active ingredient and a pharmaceutically acceptable excipient and a composition selected from a swellable composition and a reactive composition located in an immediate vicinity of one or more preselected surfaces. The coating comprising water insoluble polymer(s) and leachable component(s) is operable to be reliably removed fully from the one or more of the preselected surfaces of the tablet upon contact with an aqueous environment, but not removed from at least one of the surfaces.
