DEVICE AND PROCESS FOR MIXING A PHARMACEUTICAL COMPOSITION WITH ANOTHER AGENT AND METHOD FOR ORAL ADMINISTRATION OF THE PHARMACEUTICAL PREPARATION

Device for mixing a pharmaceutical composition stored in a chamber (38) in said device with an agent to be added shortly before administration to form a preparation to be administered. The device should be capable of being shaken without leaking. It comprises a hollow body (2) having an outlet (4), sealed by a removably closure (12) and a plunger (6), which includes a flexible sealing member (20) having a circumferential edge in sealing contact with the inner wall (8) of the hollow body. The plunger (6), the hollow body (2) and the removable closure (12) define said chamber (38). A hollow rod (30) is connected to the plunger (6) for displacing the same in the hollow body (2) and includes at least one opening, which communicates with the interior of the rod (30) with the upper side of the flexible member (20). The flexible member (20) is supported on the plunger (6), so that it can only flex downwards. At a predetermined pressure differential over the upper side and the lower side of the flexible member (20) the flexible member will flex downwards to open a communication at the inner wall (8) of the hollow body into the chamber (38), so that said agent flows into the chamber (38).