A PREFILLED INJECTION DEVICE WITH CLEANING CHAMBER

The invention relates to a prefilled injection pen for apportioning multiple set doses of a liquid drug containing a preservative. The injection pen comprises a housing structure which permanently and non-removable secures a cartridge containing the preservative containing liquid drug. The cartridge is connected to a needle cannula which further has a sharp distal tip for penetrating the skin of a user. The distal tip of the needle cannula is concealed by an axially movable needle shield at least between injections. At the distal end of the axially movable needle shield, a cleaning chamber is provided which cleaning chamber contains a volume of the same preservative containing liquid drug as present in the cartridge. The cleaning chamber is further provided with an outlet which is open to the surroundings and through which outlet air and a quantum of the preservative containing liquid drug can escape. In the proximity of the outlet, means are provided to collect the escaped quantum of the preservative containing liquid drug.