The invention is related to an apparatus comprising a valve body comprising at least two inlet channels and at least one outlet channel and forming a central cavity connecting the at least two inlet channels and the at least one outlet channel, wherein the central cavity encloses a blocking assembly arranged for closing each of the at least two inlet channels by default and for opening an inlet channel when fluid pressure is applied from that inlet channel wherein each of the at least two inlet channels is configured for fluid communication with a respective reservoir of at least two reservoirs. The invention is further related to a medical device for delivering at least two drug agents from at least two separate reservoirs comprising an apparatus of the aforementioned kind.