Needleless injector

• US 20030083611A1
• Filed: 07/19/2002
• Published: 05/01/2003
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Hunter, Ian W., Angel, Aimee B.
• Granted Patent: US 6,939,323 B2
• Time in Patent Office: Days
• US Class Current: 604/68
• CPC Class Codes: A61M 2205/0266 Shape memory materials
• CPC Class Codes: A61M 2205/0272 Electro-active or magneto-active materials
• CPC Class Codes: A61M 5/30 Syringes for injection by jet action, without needle, e.g. for use with replaceable ampoules or carpules
• CPC Class Codes: A61M 5/31511 Piston or piston-rod constructions, e.g. connection of piston with piston-rod A61M5/5066 takes precedence
• CPC Class Codes: F03G 7/065 using a shape memory element

Abstract

An injector includes a housing having a chamber for holding a liquid formulation of an active principle to be injected into a biological body and an output port in fluid communication with the chamber through which the liquid formulation is injected. A piston is positioned within the housing, and includes an end portion with substantially the same shape as the chamber. A magnetic force draws the piston and housing together to expel the liquid formulation out of the chamber through the output port.

Claims

1. An injector, comprising:

a housing having a chamber for holding a liquid formulation of an active principle to be injected into a biological body and an output port in fluid communication with the chamber, the liquid formulation being injected though the output port; and

a piston positioned within the housing, the piston including an end portion with substantially the same shape as the chamber,

the piston and housing being drawn together by a magnetic force to expel the liquid formulation out of the chamber through the output port.

2. The injector of claim 1 further comprising an inlet port for filling the chamber with the liquid formulation.

3. The injector of claim 1 further comprising an actuator attached to the piston and made of shape memory alloy, the actuator moving the piston away from the housing when a potential is applied to the actuator, and the piston moving towards the housing when the voltage is removed.

4. The injector of claim 3 wherein the actuator is one or more fibers of the shape memory alloy.

5. The injector of claim 3 wherein the shape memory alloy is Ni—

Ti.

6. The injector of claim 3 wherein the shape memory alloy is approximately 10 mm to 200 mm long.

7. The injector of claim 6 wherein the shape memory alloy contracts approximately 0.5 mm to 10 mm when the potential is applied to the alloy.

8. The injector of claim 3 wherein the shape memory alloy structure changes phase from martensite to austenite when the potential is applied to the alloy.

9. The injector of claim 3 further comprising a capacitor, wherein the potential is applied to the actuator when the capacitor discharges.

10. The injector of claim 9 wherein the capacitor has an energy output of about 100 J.

11. The injector of claim 9 wherein the capacitor has an energy output of at least about 10 J.

12. The injector of claim 1 wherein the injector has a maximum injection pressure of approximately 300 MPa.

13. The injector of claim 1 wherein the injector has an injection pressure of at least 1 Mpa

14. The injector of claim 1 wherein the injector has a cycle time of about one sec.

15. The injector of claim 1 wherein the output port has a diameter of about 50 μ

m to 200 μ

m.

16. The injector of claim 1 wherein the chamber has a tapered shape.

17. The injector of claim 1 wherein the liquid formulation is a drug.

18. The injector of claim 1 further comprising an actuator attached to the piston and made of contractile polymers, the actuator moving the piston away from the housing when a potential is applied to the actuator, and the piston moving towards the housing when the voltage is removed.

19. The injector of claim 1 further comprising an actuator attached to the piston and made of a contracting material, the actuator moving the piston away from the housing when a potential is applied to the actuator, and the piston moving towards the housing when the voltage is removed.

20. An actuator, comprising:

a fiber of shape memory alloy under tension, the tension being produced by a magnetic force; and

a capacitor which discharges a potential to the fiber to cause the fiber to contract, the fiber relaxing to a stretched state when the potential is removed.

21. The actuator of claim 20 wherein the actuator is one or more fibers of the shape memory alloy.

22. The actuator of claim 20 wherein the shape memory alloy is Ni—

Ti.

23. The actuator of claim 20 wherein the shape memory alloy is approximately 10 mm to 200 mm long.

24. The actuator of claim 23 wherein the shape memory alloy contracts approximately 0.5 mm to 10 mm when the potential is applied to the alloy.

25. The actuator of claim 20 wherein the shape memory alloy structure changes phase from martensite to austenite when the potential is applied to the alloy.

26. The actuator of claim 20 wherein the capacitor has a an energy output of about 100 J.

27. The actuator of claim 20 wherein the capacitor has a capacitance of at least 10 J.

28. An injector, comprising:

a housing having a chamber for holding a liquid formulation of an active principle to be injected into a biological body and an output port in fluid communication with the chamber, the liquid formulation being injected though the output port;

a piston positioned within the housing, the piston including an end portion with substantially the same shape as the chamber; and

an actuator attached to the piston and made of shape memory alloy,

the piston and housing being drawn together by a magnetic force, the actuator moving the piston away from the housing when a potential is applied to the actuator, and the piston moving towards the housing when the voltage is removed to expel the liquid formulation out of the chamber through the output port.

29. An actuator, comprising:

a contracting material under tension, the tension being produced by a magnetic force; and

a capacitor which discharges a potential to the fiber to cause the fiber to contract, the fiber relaxing to a stretched state when the potential is removed.

30. The actuator of claim 29 wherein the contracting material is a shape memory alloy.

31. The actuator of claim 29 wherein the contracting material is a contractile polymer.

32. A method of injecting a liquid formulation of an active principle into a biological body, comprising:

holding a liquid formulation of an active principle in a chamber of a housing, the chamber being in fluid communication with an output port through which the liquid formulation is injected;

positioning a piston within the housing, the piston including an end portion with substantially the same shape as the chamber; and

applying a magnetic force between the housing and the piston to draw the piston and the housing together;

expelling the liquid formulation from the chamber through the output port as the piston moves towards the housing.

33. The method of claim 32 further comprising filling the chamber with the liquid formulation through an inlet port of the housing.

34. The method of claim 32 further comprising applying a potential to an actuator attached to the piston to move the piston away from the housing and removing the potential to move the piston towards the housing.

35. The method of claim 34 further comprising discharging a capacitor to apply the potential to the actuator.

36. The method of claim 35 wherein the capacitor has an energy output of about 100 J.

37. The method of claim 35 wherein the capacitor has an energy output of at least 10 J.

38. The method of claim 34 wherein the actuator is made of shape memory alloy.

39. The method of claim 38 wherein the shape memory alloy is Ni—

Ti.

40. The method of claim 38 wherein the shape memory alloy is approximately 10 mm to 200 mm long.

41. The method of claim 40 wherein the shape memory alloy contracts approximately 0.5 mm to 10 mm when the potential is applied to the alloy.

42. The method of claim 38 wherein the shape memory alloy structure changes phase from martensite to austenite when the potential is applied to the alloy.

43. The method of claim 32 wherein the liquid formulation is a drug.

44. A method of actuating a fiber of shape memory alloy, comprising;

applying a tension to the fiber with a magnetic force; and

discharging a capacitor to apply a potential to the fiber to cause the fiber to contract, the fiber relaxing to a stretched state when the potential is removed.

45. The method of claim 44 wherein the capacitor has an energy output of about 100 J.

46. The method of claim 44 wherein the capacitor has an energy output of at least 10 J.

47. The method of claim 44 wherein the fiber is made of shape memory alloy.

48. The method of claim 47 wherein the shape memory alloy is Ni—

Ti.

49. The method of claim 47 wherein the shape memory alloy is approximately 10 mm to 200 mm.

50. The method of claim 49 wherein the shape memory alloy contracts approximately 0.5 mm to 10 mm when the potential is applied to the alloy.

51. The method of claim 47 wherein the shape memory alloy structure changes phase from martensite to austenite when the potential is applied to the alloy.