Drug delivery device

• US 20030135159A1
• Filed: 01/03/2003
• Published: 07/17/2003
• Est. Priority Date: 05/06/1997
• Status: Abandoned Application

• Current Assignee: Elan Pharma International Limited (Perrigo Company PLC)
• Original Assignee: Elan Pharma International Limited (Perrigo Company PLC)
• Inventors: Davidson, Diana, Cabiri, Oz, Daily, David, Lavi, Gilad, Shor, Eran, Tsals, Izrail, Brodeur, Craig, Azoulay, Avi, Rozanowich, Mario, Sahar, Miki, Stern, Jacob
• Application Number:
  US10/336,459
• Publication Number:
  US 20030135159A1
• Time in Patent Office: Days
• US Class Current: 604/141
• CPC Class Codes: A61M 2005/14204 with gas-producing electrochemical cell
• CPC Class Codes: A61M 2005/14252 with needle insertion means
• CPC Class Codes: A61M 2005/1426 with means for preventing access to the needle after use
• CPC Class Codes: A61M 2005/14264 with means for compensating influence from the environment
• CPC Class Codes: A61M 2206/22 eliminating pulsatile flows, e.g. by the provision of a dampening chamber
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/14593 the diaphragm being actuated by fluid pressure
• CPC Class Codes: A61M 5/155 pressurised by gas introduced into the reservoir
• CPC Class Codes: A61M 5/16877 Adjusting flow; Devices for setting a flow rate

Abstract

A drug delivery device having a housing having an internal reservoir in communication with a drug delivery outlet via a fluid path. An expandable chamber disposed adjacent to the reservoir forces drug from the reservoir to the outlet when supplied with a gas. A flow regulating chamber, in communication with the fluid path, is capable of volumetric changes in response to temperature and/or pressure changes. An increase in the volume of the flow regulating chamber increases flow resistance to the outlet and thereby counteracts the corresponding increase in delivery rate resulting from the expansion of the expandable chamber due to the same volumetric changes in response to temperature and/or pressure. In a preferred embodiment, an electrical circuit has a current stabilizing element in electrical communication with an electrolytic cell which supplies the gas. A throttling device maintains a higher pressure in the device to reduce possible clogging of the fluid path. In a preferred embodiment, the drug delivery device is packaged to insulate the device from atmospheric pressure and humidity.

Claims

1. A drug delivery device comprising:

a housing having an internal chamber;

an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber which forms a pair of variable area chambers;

a gas generator for expanding the area of said expandable gas chamber and decreasing the area of said internal drug reservoir;

a lumen having an inlet and an outlet;

a fluid path defined between said internal drug reservoir and said lumen input;

a flow regulator, in communication with said fluid path, for effecting volumetric changes in response to ambient condition changes, said flow regulator comprising a chamber filled with fixed volume of air and a flexible chamber surface that opens or closes said lumen inlet based on a pressure differential between said fluid path and said internal drug reservoir chamber; and

means for maintaining a specific flow rate of drug delivery, said means for maintaining a specific flow rate comprising an electrical circuit that controls said gas generator.

2. The drug delivery device of claim 1 wherein said lumen is a needle and said flexible chamber surface is a diaphragm.

3. The drug delivery device of claim 2 wherein said gas generator generates a sufficient gas pressure to drive the drug through said fluid path and to deform said diaphragm to allow said drug to flow through said needle and prevent a bolus delivery of drug that may be caused by an occlusion in said needle.

4. A drug delivery device comprising:

a housing having an internal chamber;

an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber which form. a pair of variable area chambers;

a gas generator for expanding the area of said expandable gas chamber and decreasing the area of said internal reservoir;

a drug delivery outlet;

a fluid path defined between said internal reservoir and said drug delivery outlet;

a flow regulator, in communication with said fluid path, for effecting volumetric changes in response to ambient condition changes; and

means for maintaining a specific flow rate of drug delivery, said means for maintaining a specific flow rate comprising;

an electrical circuit that controls said gas generator; and

an electrical switch, coupled to said electrical circuit, that which controls power to said electrical circuit, said electrical switch being is controlled by the pressure differential between said expandable gas chamber and a third chamber filled with a predetermined volume of gas.

5. The drug delivery device of claim 4 wherein said electrical switch comprises a conductive lever that interfaces with a conductive membrane which forms a surface of said third chamber filled with said predetermined volume of gas, said lever either contacting, or not contacting, said membrane which can flex depending on the pressure differential between said expandable gas chamber and said third chamber, to open or close said switch.

6. The drug delivery device of claim 4 wherein said electrical switch cannot be closed, once opened, said switch comprising:

an isolator membrane that forms a flexible surface of said third chamber;

a conductive thread that runs along said flexible surface; and

said conductive thread conveying power to said electrical circuit whenever the pressure in said expandable gas chamber is less than the pressure in said third chamber, said conductive thread severing whenever the pressure in said expandable gas chamber exceeds the pressure in said third chamber, thereby terminating power to said electrical circuit.

7. The drug delivery device of claim 4 wherein said electrical switch comprises:

a channel having a first end exposed to said expandable gas chamber and a second end exposed to said third chamber;

a pair of electrodes across the width of said channel;

a conductive metal droplet that can move inside said chamber; and

wherein whenever the pressure in said expandable gas chamber is less than the pressure in said third chamber, said conductive metal droplet electrically couples said pair of electrodes together and whenever the pressure in said expandable gas chamber exceeds the pressure in said third chamber, said conductive meal droplet is driven out of contact with said pair of electrodes.

8. The drug delivery device of claim 7 wherein said conductive metal droplet comprises mercury.

9. A method of controlling the rate of drug delivery, said method comprising the steps of:

providing a drug delivery device having a housing including an internal chamber and an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber that form a pair of variable area chambers;

expanding the area of the expandable gas chamber and decreasing the area of the internal area by generating a gas in an electrolytic cell controlled by an electrical circuit to drive the drug out of said reservoir at a specific flow rate; and

altering the flow which is in communication with the fluid path between the internal reservoir and a needle outlet in response to ambient condition changes by valving a needle input and requiring that the driven drug pressure required to open the valve be equal to, or greater than, ambient pressure.

10. A method of preventing a bolus delivery of drug from a drug delivery device, said method comprising the steps of:

providing a drug delivery device having a housing including an internal chamber and an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber that form a pair of variable area chambers;

expanding the area of the expandable gas chamber and decreasing the area of the internal area by generating a gas in an electrolytic cell controlled by an electrical circuit to drive the drug out of said reservoir at a specific flow rate; and

altering the flow which is in communication with the fluid path between the internal reservoir and a needle outlet by valving a needle input and requiring that the driven drug pressure required to open the valve be greater than back pressure created by an occlusion of said needle.

11. A method of preventing a bolus delivery of drug from a drug delivery device, said method comprising the steps of:

providing a drug delivery device having a housing including an internal chamber and an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber that form a pair of variable area chambers;

expanding the area of the expandable gas chamber and decreasing the area of the internal area by generating a gas in an electrolytic cell controlled by an electrical circuit to drive the drug out of said reservoir at a specific flow rate; and

de-activating said generation of gas by sensing a pressure differential between said expandable gas chamber and a reference gas chamber wherein the pressure in said expandable gas chamber exceeds the pressure in said reference gas chamber.

12. The method of claim 11 further comprising the step of re-activating said generation of gas whenever the pressure in said expandable gas chamber is less than the pressure in said reference gas chamber.

13. A drug delivery device comprising:

a housing having an internal chamber;

an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber which form a pair of variable area chambers;

an electrolytic cell controlled by an electrical circuit which generates a gas for expanding the area of the expandable gas chamber and decreasing the area of said internal reservoir;

a drug delivery outlet;

a fluid path defined between said internal reservoir and said drug delivery outlet;

a flow regulator, in communication with said fluid path, for effecting volumetric changes in response to ambient condition changes; and

a visual drug quantity indicator carried by said housing.

14. The drug delivery device of claim 13 wherein said elastomeric diaphragm comprises a color and wherein said visual drug quantity indicator comprises a window having a transparent portion and a portion having the color of said elastomeric diaphragm and wherein the color appearing in said window informs a user of the quantity of drug in said device.

15. The drug delivery device of claim 13 further comprising a visual usage indicator indicating proper usage of said device.

16. The drug delivery device of claim 15 wherein said visual usage indicator comprises a component which is to be hidden when properly installed on the user'"'"'s body, said component including a color that can only be seen by the user if said device is installed improperly.

17. The drug delivery device of claim 15 wherein said visual usage indicator comprises a component which is to be removed prior to activating said device, said component including a color that alerts the user to remove said component before said device can be activated.

18. The drug delivery device of claim 13 wherein said electrolytic cell is covered by a foil cover.

19. The drug delivery device of claim 18 further comprising an activation mechanism having an electrical contact and a puncturing device for puncturing said foil cover of said electrolytic cell.

20. A method of controlling the rate of drug delivery comprising the steps of:

providing a drug delivery device having a housing including an internal chamber and an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber that form a pair of variable area chambers;

expanding the area of the expandable gas chamber and decreasing the area of the internal area by generating a gas in an electrolytic cell controlled by an electrical circuit;

altering the flow which is in communication with the fluid path between the internal reservoir and a drug delivery outlet in response to ambient condition changes; and

controlling residual air volume, material permeability, material properties of plastic material in said device and said membrane seal.

21. A method of controlling the rate of drug delivery comprising the steps of:

providing a drug delivery device having a housing including an internal chamber and an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber that form a pair of variable area chambers;

expanding the area of the expandable gas chamber and decreasing the area of the internal area by generating a gas in an electrolytic cell controlled by an electrical circuit;

altering the flow which is in communication with the fluid path between the internal reservoir and a drug delivery outlet in response to ambient condition changes; and

packaging said drug delivery system to insulate said device from environmental conditions.

22. The method of claim 21 wherein one of said environmental conditions is atmospheric pressure.

23. The method of claim 21 wherein one of said environmental conditions is humidity.

24. A method of controlling the rate of drug delivery comprising the steps of:

providing a drug delivery device having a housing including an internal chamber and an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber that form a pair of variable area chambers;

expanding the area of the expandable gas chamber and decreasing the area of the internal area by generating a gas in an electrolytic cell controlled by an electrical circuit;

altering the flow which is in communication with the fluid path between the internal reservoir and a drug delivery outlet in response to ambient condition changes; and

including an insertion device for accommodating design tolerances.

25. The method of claim 24 wherein said insertion device comprises foam.

31. The drug delivery device of claim 24 wherein said drug delivery outlet comprises a needle extending from said housing for penetration of the skin of a subject.

32. The drug delivery device of claim 31 further comprising a displaceable cover that is coupled to said housing such that displacement of said housing relative to said cover when said cover has been applied to the skin of a subject causes said delivery needle to penetrate the skin of the subject.

33. The drug delivery device of claim 32 wherein said displaceable cover is displaceable relative to said housing between a first position in which said needle is concealed from the exterior of said device, a second position in which said delivery needle protrudes from said device for penetration of the skin, and wherein said device further comprises means for locking said device in said first position after a single reciprocation of said device from said first position to said second position and back to said first position.

34. The drug delivery device of claim 33 further comprising a visual usage indicator indicating proper usage of said device.

35. The drug delivery device of claim 34 wherein said visual usage indicator comprises a component which is to be hidden when properly installed on the user'"'"'s body, said component including a color that can only be seen by the user if said device is installed improperly.

36. The drug delivery device of claim 34 wherein said visual usage indicator comprises a component which is to be removed prior to activating said device, said component including a color that alerts the user to remove said component before said device can be activated.

37. The drug delivery device of claim 33 wherein movement of said cover relative to said housing is initially prevented by a removable locking member.

38. The drug delivery device of claim 37 wherein the presence of said removable locking member also prevents said means for providing a gas from being actuated.

41. The drug delivery device of claim 38 further comprising packaging of said drug delivery device to insulate said device from environmental conditions.

42. The drug delivery device of claim 41 wherein one of said environmental conditions is atmospheric pressure.

43. The drug delivery device of claim 41 wherein one of said environmental conditions is humidity.

26. A drug delivery device comprising:

a housing having an internal chamber;

providing a drug delivery device having a housing including an internal chamber and an elastomeric diaphragm within said internal chamber for defining an internal drug reservoir chamber and an expandable gas chamber that form a pair of variable area chambers;

a gas generator having an electrolytic cell and an electrical circuit, said gas generator providing gas at a controllable rate into said expandable gas chamber;

said electrical circuit having a current stabilizing element in electrical communication with said electrolytic cell;

a drug delivery outlet; and

a fluid path defined between said internal reservoir and said drug delivery outlet and said reservoir.

27. The drug delivery device of claim 26 further comprising a flow regulator, in communication with said fluid path, for effecting volumetric changes in response to ambient condition changes.

28. The drug delivery device of claim 26 wherein said drug delivery outlet comprises a tube extending from said housing.

29. The drug delivery device of claim 28 wherein said tubing is coupled to said housing at an outlet port having a luer connection.

30. The drug delivery device of claim 29 further comprising an epidural needle.

39. The drug delivery device of claim 27 wherein said flow regulator includes a member having a cavity and a flow diaphragm defining a closed space, said member being movable in said flow path.

40. The drug delivery device of claim 27 wherein said flow regulating chamber includes a member having a cavity and a flow diaphragm defining a closed space, said member being rigid relative to said flow path.

44. The drug delivery device of claim 26 further comprising a visual drug quantity indicator and wherein said elastomeric diaphragm comprises a color, said visual drug quantity indicator comprising a window having a transparent portion and a portion having the color of said elastomeric diaphragm and wherein the color appearing in said window informs a user of the quantity of drug in said device.

45. The drug delivery device of claim 44 wherein said drug delivery outlet comprises the outlet of a needle having an inlet, said drug delivery device further comprising a flow regulator, in communication with said fluid path, for effecting volumetric changes in response to ambient condition changes, said flow regulator comprising a chamber filled with a fixed volume of air and a flexible chamber surface that opens or closes said needle inlet based on a pressure differential between said fluid path and said internal drug reservoir chamber.

46. The drug delivery device of claim 45 wherein said current stabilizing element has at least a pair of resistors in series.

47. The drug delivery device of claim 46 further comprising a pressure sensitive mechanism that detects increased pressure in said internal chamber and prevents a pressure build-up.

48. The drug delivery device of claim 47 wherein said electrolytic cell is covered by a foil cover.

49. The drug delivery device of claim 49 further comprising an activation mechanism including an electrical contact and a puncturing device for puncturing said foil cover of said electrolytic cell.

50. The drug delivery device of claim 49 further comprising a visual usage indicator for indicating proper usage of said device.