this invention relates to a pharmaceutical dosage form for the phase - controlled and chronotherapeutic delivery of at least one and , preferably , several pharmaceutically active ingredients . the dosage form has a carrier platform which ,— preferably , is a polymer having known biodegradable characteristics . the platform may include a pharmaceutically active ingredient &# 39 ; which is released over a predetermined period of time as the platform polymer degrades . at least one pharmaceutically active ingredient in the form of a disc is embedded in the platform and , once the polymer of the platform has degraded , the disc is released and releases its ingredient in the same location as that of the platform or it travels to another region of the body where it releases its ingredient .