Needle-free injection system

• US 20050267403A1
• Filed: 05/28/2004
• Published: 12/01/2005
• Est. Priority Date: 05/28/2004
• Status: Active Grant

• Current Assignee: Inovio Pharmaceuticals, Inc.
• Original Assignee: Bioject Incorporated
• Inventors: Miller, Robert A., Landau, Sergio, Daellenbach, Keith K., Beylund, Ryan R., Staylor, John L., Sedler, Theodore Walaka, Bonicatto, James M.
• Granted Patent: US 7,717,874 B2
• Time in Patent Office: Days
• US Class Current: 604/70
• CPC Class Codes: A61M 2005/2407 from the rear
• CPC Class Codes: A61M 2005/2488 via rotation, e.g. threads or bayonet
• CPC Class Codes: A61M 2005/287 by displacing occluding plugs
• CPC Class Codes: A61M 2005/3104 Caps for syringes without needle
• CPC Class Codes: A61M 5/2053 Media being expelled from injector by pressurised fluid or vacuum for infusion A61M5/145, A61M5/155
• CPC Class Codes: A61M 5/24 Ampoule syringes, i.e. syringes with needle for use in combination with replaceable ampoules or carpules, e.g. automatic ampoules or carpules A61J1/06
• CPC Class Codes: A61M 5/30 Syringes for injection by jet action, without needle, e.g. for use with replaceable ampoules or carpules

Abstract

A needle-free injection device in which a gas cartridge or other source of pressurized gas is used to advance a piston and forcibly expel injectable fluid out through an injection orifice. When a gas cartridge is used, the gas cartridge may be moveable from an initial position to an actuating position in which gas is released to drive the injection, and a recoil inhibiter may be employed to prevent the gas cartridge from moving back to the initial position. A gas cartridge seal may be disposed on the gas cartridge and moveable with the gas cartridge to seal the gas cartridge against an interior wall of a gas cartridge housing. The needle-free injection device may also be configured so that sealing is compromised upon full advancement of the piston, so as to de-pressurize the device after delivery of an injection.

Claims

1. A needle-free injection device, comprising:

a piston configured to be advanced during delivery of an injection;

a gas cartridge disposed within a gas cartridge housing and movable relative to the gas cartridge housing from an initial position to an actuating position, in which a pierceable sealed opening at a forward end of the gas cartridge is pierced by a piercing member to enable pressurized gas to be released from the gas cartridge to act upon a rearward end of the piston, thereby driving the piston forward to forcibly expel injectable fluid out through an injection orifice; and

a recoil inhibiter configured to constrain movement of the gas cartridge so that the gas cartridge is movable from the initial position to the actuating position, but is prevented from moving from the actuating position back to the initial position.

2. The device of claim 1, where the recoil inhibiter includes a ratchet structure and pawl device that interact to permit movement of the gas cartridge from the initial position to the actuating position and prevent movement of the gas cartridge from the actuating position back to the initial position.

3. The device of claim 2, where the ratchet structure is formed on the gas cartridge housing and the pawl device is provided rearward of the gas cartridge and configured to advance with the gas cartridge within the gas cartridge housing as the gas cartridge is moved toward the actuating position.

4. The device of claim 3, where the ratchet structure is formed in an elongate slot provided in the gas cartridge housing, and where the pawl device includes resilient legs that ratchet against edges of the elongate slot as the pawl device is moved forward relative to the gas cartridge housing.

5. The device of claim 2, further comprising a spring disposed rearward of the gas cartridge, and where the gas cartridge is moved forward to the actuating position through operation of the spring.

6. The device of claim 1, further comprising a spring disposed rearward of the gas cartridge, and where the gas cartridge is moved forward to the actuating position through operation of the spring.

7. The device of claim 6, further comprising a trigger mechanism that holds the spring in an initial compressed state, and where, upon operation of the trigger mechanism, the spring is permitted to decompress and thereby move the gas cartridge forward from the initial position toward the actuating position.

8. The device of claim 7, where the trigger mechanism includes an exterior sleeve configured to be moved by a user to actuate the trigger mechanism and cause the spring to be released from the initial compressed state.

9. The device of claim 1, further comprising a gas seal at the rearward end of the piston, the gas seal being configured to seal a variable-volume gas chamber defined between the rearward end of the piston and the gas cartridge, where the needle-free injection device is configured so that the gas seal is compromised upon advancement of the piston to a forward-most position, so as to de-pressurize the variable-volume gas chamber after delivery of an injection.

10. The device of claim 9, where the gas seal is compromised automatically without user intervention upon advancement of the piston to the forward-most position.

11. The device of claim 10, where the gas seal interacts with an interior wall of a piston housing in which the piston is at least partially disposed to seal the variable-volume gas chamber, and where a seal-defeating irregularity is formed on the interior wall of the piston housing in a location such that the gas seal comes into contact with the seal-defeating irregularity as the piston advances to the forward-most position.

12. The device of claim 11, where the seal-defeating irregularity is located on the interior wall of the piston housing so that the gas seal does not contact the seal-defeating irregularity until the piston has advanced substantially all the way to the forward-most position.

13. The device of claim 11, where the seal defeating irregularity includes an elongate rib formed on the interior wall of the piston housing.

14. The device of claim 11, where a vent hole is defined through the piston housing such that, upon contact of the gas seal with the seal-defeating irregularity, pressurized gas is permitted to escape from the variable-volume gas chamber past the gas seal and out through the vent hole.

15. The device of claim 1, further comprising a gas cartridge seal disposed on the gas cartridge and configured to move with the gas cartridge relative to the gas cartridge housing and sealingly engage an interior wall of the gas cartridge housing to inhibit gas from passing rearward past the gas cartridge seal between the gas cartridge and the gas cartridge housing.

16. A needle-free injection device, comprising,

a housing;

a piston disposed at least partially within the housing, the piston having a forward end and a rearward end, the piston being configured to advance relative to the housing from a rearward-most position to a forward-most position during delivery of an injection, so as to cause injectable fluid to be expelled out through an injection orifice;

a pressurized gas source configured to deliver pressurized gas to act upon the rearward end of the piston; and

a gas seal at the rearward end of the piston, the gas seal being configured to seal a variable-volume gas chamber defined within the housing between the rearward end of the piston and the pressurized gas source,

where the needle-free injection device is configured so that the gas seal is compromised upon advancement of the piston to the forward-most position, so as to de-pressurize the variable-volume gas chamber after delivery of an injection.

17. The device of claim 16, where the gas seal is compromised automatically without user intervention upon advancement of the piston to the forward-most position.

18. The device of claim 17, where the gas seal interacts with an interior wall of the housing to seal the variable-volume gas chamber, and where a seal-defeating irregularity is formed on the interior wall in a location such that the gas seal comes into contact with the seal-defeating irregularity as the piston moves from the rearward-most position to the forward-most position.

19. The device of claim 18, where the seal-defeating irregularity is located on the interior wall of the housing so that the gas seal does not contact the seal-defeating irregularity until the piston has advanced substantially all the way to the forward-most position.

20. The device of claim 18, where the seal defeating irregularity includes an elongate rib formed on the interior wall of the housing.

21. The device of claim 18, where a vent hole is defined through the housing such that, upon contact of the gas seal with the seal-defeating irregularity, pressurized gas is permitted to escape from the variable-volume gas chamber past the gas seal and out through the vent hole.

22. The device of claim 16, where the pressurized gas source is a gas cartridge movably disposed within a gas cartridge housing so that the gas cartridge is movable from an initial position to an actuating position, in which a pierceable sealed opening at a forward end of the gas cartridge is pierced by a piercing member to enable pressurized gas to be released from the gas cartridge to act upon a rearward end of the piston, thereby driving the piston forward to forcibly expel injectable fluid out through an injection orifice.

23. The device of claim 22, further comprising a recoil inhibiter configured to constrain movement of the gas cartridge so that the gas cartridge is movable from the initial position to the actuating position, but is prevented from moving from the actuating position back to the initial position.

24. The device of claim 23, where the recoil inhibiter includes a ratchet structure and pawl device that interact to permit movement of the gas cartridge from the initial position to the actuating position and prevent movement of the gas cartridge from the actuating position back to the initial position.

25. The device of claim 22, further comprising a gas cartridge seal disposed on the gas cartridge and configured to move with the gas cartridge relative to the gas cartridge housing and sealingly engage an interior wall of the gas cartridge housing to inhibit gas from passing rearward past the gas cartridge seal between the gas cartridge and the gas cartridge housing.

26. A needle-free injection device, comprising:

a piston configured to be advanced during delivery of an injection;

a gas cartridge disposed within a gas cartridge housing and movable in a forward direction relative to the gas cartridge housing from an initial position to an actuating position, in which a pierceable sealed opening at a forward end of the gas cartridge is pierced by a piercing member to enable pressurized gas to be released from the gas cartridge to act upon a rearward end of the piston, thereby driving the piston forward to forcibly expel injectable fluid out through an injection orifice; and

a gas cartridge seal disposed on the gas cartridge and configured to move with the gas cartridge relative to the gas cartridge housing and sealingly engage an interior wall of the gas cartridge housing to inhibit gas from passing rearward past the gas cartridge seal between the gas cartridge and the gas cartridge housing.

27. The device of claim 26, where the gas cartridge seal has a V-shaped cross section.

28. The device of claim 27, where a mouth of the V-shaped cross section faces forward.

29. The device of claim 26, where the gas cartridge seal is disposed around a tapered neck portion of the gas cartridge.

30. The device of claim 26, further comprising a recoil inhibiter configured to constrain movement of the gas cartridge so that the gas cartridge is movable from the initial position to the actuating position, but is prevented from moving from the actuating position back to the initial position.

31. The device of claim 30, where the recoil inhibiter includes a ratchet structure and pawl device that interact to permit movement of the gas cartridge from the initial position to the actuating position and prevent movement of the gas cartridge from the actuating position back to the initial position.

32. The device of claim 31, where the ratchet structure is formed on the gas cartridge housing and the pawl device is provided rearward of the gas cartridge and configured to advance with the gas cartridge within the gas cartridge housing as the gas cartridge is moved toward the actuating position.

33. The device of claim 32, where the ratchet structure is formed in an elongate slot provided in the gas cartridge housing, and where the pawl device includes resilient legs that ratchet against edges of the elongate slot as the pawl device is moved forward relative to the gas cartridge housing.

34. The device of claim 30, further comprising a spring disposed rearward of the gas cartridge, and where the gas cartridge is moved forward to the actuating position through operation of the spring.

35. A needle-free injection device, comprising:

a housing;

a piston disposed at least partially within the housing and configured to be advanced relative to the housing from an initial position to an actuated position during delivery of an injection, the piston including a forward end and a stopper located rearward of the forward end; and

an injectable fluid seal at the forward end of the piston, the injectable fluid seal being configured to seal a variable-volume injectable fluid chamber located forward of the piston, such that injectable fluid is expelled from the variable-volume injectable fluid chamber and out through an injection orifice upon advancement of the piston,

where the housing includes an obstruction configured to block the stopper upon advancement of the piston to the actuated position to thereby prevent further advancement of the piston beyond the actuated position.

36. The device of claim 35 where the stopper is located closer to a rearward end of the piston than to the forward end of the piston.

37. The device of claim 35, where the piston is configured and disposed within the housing so that, when the piston is in the initial position, the stopper of the piston is spaced by a predetermined distance from the obstruction.

38. The device of claim 37, where the predetermined distance is based upon a desired volume of injectable fluid to be injected.

39. The device of claim 37, where the predetermined distance is based upon a desired distance for the piston to be advanced during delivery of an injection.

40. The device of claim 35, where the piston includes an elongate shaft portion extending forward of the stopper.

41. The device of claim 40, where the forward end of the piston includes a concavity adapted to receive a correspondingly-shaped plunger member, the plunger member being configured to be pushed forward by the piston within the variable-volume injectable fluid chamber upon advancement of the piston.

42. The device of claim 41, where the concavity of the piston is generally conical, and is adapted to receive a corresponding conical surface of the plunger.

43. The device of claim 40, where the stopper has a cross section that extends farther radially outward than a cross section of the elongate shaft portion.

44. The device of claim 43, where the stopper includes a plurality of axial ribs that extend radially outward from an injection axis of the injection device.

45. The device of claim 40, where a hole is defined through the obstruction, the hole and elongate shaft portion of the piston being sized to permit the elongate shaft portion to advance through the hole.

46. The device of claim 45, where the stopper of the piston is sized so that the stopper is blocked by the obstruction and prevented from passing through the hole defined through the obstruction.

47. A needle-free injection device, comprising:

a piston configured to be advanced during delivery of an injection; and

a gas cartridge disposed within the needle-free injection device and movable in a forward direction to an actuating position, in which a pierceable sealed opening of the gas cartridge is brought into contact with a piercing member to enable pressurized gas from the gas cartridge to be released and act upon the piston, thereby driving the piston forward to cause injectable fluid to be expelled out of the needle-free injection device through an injection orifice,

where the piston and gas cartridge are disposed within a housing assembly including first and second housing pieces that are threadably assembled together so that a toothed surface on the first housing piece engages a toothed surface on the second housing piece, where the toothed surfaces grip one another to inhibit attempts to unthread the first and second housing pieces.

48. The device of claim 47, where on the first housing piece, the toothed surface is formed on an outer diameter of the first housing piece, and where on the second housing piece, the toothed surface is formed on an inner diameter of the second housing piece.

49. The device of claim 48, where the first housing piece is a nozzle, with the injection orifice being formed at a forward end of the nozzle.

50. The device of claim 49, where the second housing piece is a piston housing within which the piston is at least partially disposed.

51. The device of claim 47, where the first and second housing pieces are threadably assembled together via engagement of threads on the first housing piece with threads on the second housing piece, and where for each of the first and second housing pieces, the toothed surface includes teeth that are arranged generally perpendicular to the threads of the housing piece.

52. The device of claim 51, where at least some of the teeth have an asymmetrical cross-section configured to increase the torque required to unscrew the first and second housing pieces from each other, relative to the torque required to screw the housing pieces together during assembly.

53. The device of claim 47, where the needle-free injection device is pre-filled with a single dose of injectable fluid.