Cartridge and needle assembly in combination

A cartridge and needle assembly in combination for a re-useable injection device, comprising:

• a cartridge containing a pharmaceutical liquid drug and having a distal end closed by a pierceable membrane and a proximal end closed by a movable plunger, and
• a needle assembly comprising:
• a housing structure supporting a needle cannula having a distal end with a tip and a proximal end wherein the housing structure comprises a hub carrying the needle cannula and which hub is axial movable in the proximal direction relative to the housing structure from an initial position to an injection position, and
• a telescopic needle shield which is axially movable relatively to the housing structure between a first extended position and a second retracted position and which needle shield is urged into the first extended position by a resilient element,
• wherein the telescopic shield carries a reservoir containing a liquid preservative for cleaning at least the tip of the needle cannula between subsequent injections, wherein the reservoir comprises a distal septum and a proximal septum;
• wherein the needle assembly is permanently attached to the cartridge to form one unitary unit, and
• wherein at least the tip of the needle cannula in the first extended position of the telescopic needle shield is located inside the reservoir and wherein at least the tip of the needle cannula in the second retracted position of the telescopic needle shield is located distal to the telescopic needle shield to perform an injection.