Drug delivery device with pneumatic power pack

A drug delivery device comprising:

• a main housing;
• a medicament container arranged in the main housing, wherein the medicament container comprises a medicament;
• a needle cover axially movable with respect to the main housing;
• and
• a pneumatic power pack arranged in the main housing, wherein the pneumatic power pack comprises:
• (i) a pressurized gas source having a valve and storing pressurized gas;
• (ii) a sleeve having an inner wall, wherein the sleeve is axially moveable with respect to the main housing;
• and
• (iii) a plunger comprising an inner chamber, wherein the plunger is axially movable with respect to both the sleeve and the medicament container, wherein the plunger is in sliding gas-tight engagement with the inner wall of the sleeve, and wherein the sleeve and the inner chamber are configured to receive pressurized gas released from the pressurized gas source,
• wherein axial movement of the needle cover in a proximal direction causes axial movement of the sleeve in the proximal direction, wherein the axial movement of the sleeve in the proximal direction activates the valve to release the pressurized gas, and wherein the released pressurized gas flows into both the sleeve and the inner chamber and propels the plunger in a distal direction with respect to the sleeve and the medicament container, so as to eject the medicament from the medicament container.

A drug delivery device comprising:

• a main housing;
• a medicament container arranged in the main housing, wherein the medicament container comprises a medicament;
• and
• a pneumatic power pack arranged in the main housing, wherein the pneumatic power pack comprises:
• (i) a pressurized gas source storing pressurized gas;
• (ii) a valve for the pressurized gas source;
• (iii) a sleeve having an inner wall;
• and
• (iv) a plunger comprising an inner chamber and a pressure release valve configured to release pressure from the inner chamber when the pressure in the inner chamber reaches a threshold pressure level,
• wherein the plunger is axially movable with respect to both the sleeve and the medicament container,
• wherein the plunger is in sliding gas-tight engagement with the inner wall of the sleeve,
• wherein the sleeve and the inner chamber are configured to receive pressurized gas released from the pressurized gas source,
• wherein the valve is configured to release the pressurized gas upon activation of the valve, and
• wherein the released pressurized gas is configured to flow into both the sleeve and the inner chamber to propel the plunger in a distal direction with respect to the sleeve and the medicament container with a substantially constant force, such that the plunger moves into the medicament container to eject the medicament from the medicament container.