Drug delivery device

• US 6,530,900 B1
• Filed: 05/23/2000
• Issued: 03/11/2003
• Est. Priority Date: 05/06/1997
• Status: Active Grant

• Current Assignee: Alkermes Pharma Ireland Limited (Alkermes plc)
• Original Assignee: Elan Pharma International Limited (Perrigo Company PLC)
• Inventors: Shor, Eran, Brodeur, Craig, Azoulay, Avi, Rozanowich, Mario, Sahar, Miki, Davidson, Diana, Stern, Jacob, Cabiri, Oz, Daily, David, Lavi, Gilad, Tsals, Izrail
• Primary Examiner(s): Mendez, Manuel
• Assistant Examiner(s): HAN, MARK K
• Application Number:
  US09/577,033
• Time in Patent Office: 1,022 Days
• Field of Search: 604/132, 604/141, 604/148, 604/145, 604/146, 604/246-249, 604/167-1-1, 604/19, 604/48, 604/65, 604/93.01, 604/131, 604/133, 604/140, 604/173, 604/174, 604/180, 604/890.1, 604/891.1
• US Class Current: 604/132
• 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 the internal chamber and defining a pair of variable area chambers, an internal drug reservoir chamber and expandable gas chamber;

an electrolytic cell that generates a gas for expanding the area of the expandable gas chamber and decreasing the area of the internal reservoir, said electrolytic cell having an electrical resistance;

a drug delivery outlet;

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

a flow regulator, in communication with the fluid path, which is capable of volumetric changes in response to ambient conditions changes; and

a means for maintaining a specific flow rate of drug delivery even though said electrical resistance may vary.

2. The drug delivery device of claim 1 wherein the means for maintaining a specific flow rate comprises an electrical circuit having a voltage source and resistive means in electrical communication with said electrolytic cell, said resistive means dropping the majority of the voltage supplied by said voltage source.

3. The drug delivery device of claim 2 wherein said voltage source comprises at least two batteries and said resistive means comprises at least two resistors in series.

4. The drug delivery device of claim 1 wherein said electrolytic cell is covered by a foil cover.

5. The drug delivery device of claim 4 further comprising an activation mechanism having a puncturing device for puncturing the foil cover of said electrolytic cell and an electrical contact.

6. A drug delivery device comprising:

a housing having an internal reservoir and an expandable chamber disposed relative to the reservoir;

a drug delivery needle extending from the housing for penetration of the skin of a subject, the needle having an outlet for drug delivery; and

a fluid path defined between the delivery needle outlet and the reservoir,

an electrolytic cell for generating a gas for expanding the area of the expandable chamber;

an electrical circuit having a voltage source and resistive means in electrical communication with said electrolytic cell, said resistive means dropping the majority of the voltage supplied by said voltage source.

7. The drug delivery device of claim 6 further comprising a flow regulating chamber, in communication with the fluid path, which is capable of volumetric changes in response to ambient condition changes.

8. The device according to claim 6, wherein the flow regulating chamber is associated with a blocking member which moves within the fluid path upon expansion of the flow regulating chamber so as to restrict the flow of drug.

9. The device according to claim 8, wherein the blocking member comprises a formation provided on a displaceable member which at least partially bounds the flow regulating chamber, the formation being disposed adjacent to an inlet of a conduit forming part of the fluid path, such that restriction of the fluid path occurs when the blocking member is moved into the inlet of the conduit.

10. The device according to claim 8, wherein the blocking member is adapted to cut off the fluid path completely with a predetermined degree of expansion of the flow regulating chamber.

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

providing a drug delivery device having a housing having an internal chamber and an elastomeric diaphragm within the internal chamber and defining a pair of variable area chambers, an internal drug reservoir chamber and expandable gas chamber;

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 that uses a resistive means to drop most of the voltage from a voltage source that is in electrical communication with the electrolytic cell; and

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.