Needleless injector

• US 6,939,323 B2
• Filed: 07/19/2002
• Issued: 09/06/2005
• 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.
• Primary Examiner(s): Luccheshi, Nicholas
• Assistant Examiner(s): Han, Mark K.
• Application Number:
  US10/200,574
• Publication Number:
  US 20030083611A1
• Time in Patent Office: 1,145 Days
• Field of Search: 604/48, 604/68, 604/69, 604/70, 604/71, 604/72, 604/73, 604/131, 604/134, 604/181, 604/187, 605/27, 605/28
• US Class Current: 604/134
• 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 fomulation being injected through 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 adapted to force the piston away from the housing in opposition to a magnetic force, the piston and housing being drawn together by a magnetic force in response to the actuator relaxing its force on the piston 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 wherein the actuator is made of a 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.

32. The injector of claim 1, wherein the magnetic force is supplied by a permanent magnet.

20. 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.

21. 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 through 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; and

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.

22. The injector of claim 21 wherein the actuator is one or mare fibers of the shape memory alloy.

23. The injector of claim 21 wherein the shape memory alloy is Ni—

Ti.

24. The injector of claim 21 wherein the shape memory alloy is approximately 10 mm to 200 mm long.

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

26. The injector of claim 21 wherein the shape memory alloy structure changes phase from martensite to austenite when the potential is applied to the alloy.

27. The injector of claim 21 further comprising a capacitor, wherein the potential is applied to the actuator when the capacitor discharges.

28. The injector of claim 27 wherein the capacitor has an energy output of about 100 J.

29. The injector of claim 27 wherein the capacitor has an energy output of at least about 10 J.

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

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