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 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.본 발명은 (a) 활성 성분 및 약제학적 허용가능한 부형제를 포함하는 코어, 및 (b) 상기 코어를 둘러싸는 실질적으로 에틸 셀룰로오스로 구성된 코팅을 포함하는 경구용 약물 전달 시스템을 제공한다.
