PISTON-DRIVEN DRUG PUMP DEVICES

• US 20110275987A1
• Filed: 04/20/2011
• Published: 11/10/2011
• Est. Priority Date: 04/20/2010
• Status: Abandoned Application

• Current Assignee: MiniPumps, LLC
• Original Assignee: MiniPumps, LLC
• Inventors: Lai, Alice, Tai, Yu-Chong, Shih, Jason, Humayun, Mark, Li, Po-Ying, CAFFEY, SEAN
• Application Number:
  US13/091,042
• Publication Number:
  US 20110275987A1
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2005/14204 with gas-producing electrochemical cell
• CPC Class Codes: A61M 2205/3523 using telemetric means
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 2210/0612 Eyes
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/14526 the piston being actuated by fluid pressure
• CPC Class Codes: A61M 5/14593 the diaphragm being actuated by fluid pressure
• CPC Class Codes: A61M 5/1684 by detecting the amount of infusate remaining, e.g. signalling end of infusion
• CPC Class Codes: A61M 5/16886 for measuring fluid flow rate, i.e. flowmeters

Abstract

In piston-pump drug-delivery devices, changes in friction between the piston and vial in which it moves may be reduced and/or compensated for by suitable surface coatings and/or feedback control.

Claims

1. A drug pump device comprising:

a vial comprising a drug reservoir therein;

a piston movably disposed inside the vial, a first side of the piston facing the drug reservoir;

a pump for applying pressure to a second side of the piston so as to move the piston to cause drug delivery from the reservoir;

at least one sensor for measuring at least one parameter indicative of a rate of drug delivery from the reservoir; and

a controller responsive to the sensor for adjusting the pressure so as to compensate for variations in friction between the piston and an interior surface of the vial.

2. The device of claim 1, wherein the controller compensates for variations in friction due to a difference between a static coefficient of friction and a dynamic coefficient of friction between the piston and the interior surface of the vial.

3. The device of claim 2, wherein at least one of the vial or the piston comprises a surface coating that reduces the difference between the static coefficient of friction and the dynamic coefficient of friction between the piston and the interior surface of the vial.

4. The device of claim 3, wherein the surface coating reduces the static coefficient of friction between the piston and the interior surface of the vial.

5. The device of claim 3, wherein the surface coating comprises polytetrafluoroethylene.

6. The device of claim 3, wherein the surface coating comprises parylene.

7. The device of claim 1, wherein the controller compensates for variations in friction due to a changing surface property of at least one of the piston or the vial.

8. The device of claim 1, wherein the vial comprises at least one of glass or a polymer.

9. The device of claim 1, wherein the vial is formed from a conventional drug vial.

10. The device of claim 1, wherein the pump is an electrolysis pump.

11. The device of claim 10, wherein the controller adjusts the pressure by adjusting a rate of electrolysis.

12. The device of claim 1, further comprising a cannula conducting liquid from the drug reservoir.

13. The device of claim 12, wherein the at least one sensor comprises a flow sensor positioned in the cannula.

14. The device of claim 1, wherein the at least one sensor comprises at least one of a pressure sensor or a barometric sensor.

15. The device of claim 1, wherein the at least one sensor comprises a position sensor associated with the piston.

16. The device of claim 15, wherein the position sensor comprises a magnet associated with the piston and an induction coil surrounding the vial.

17. The device of claim 1, wherein the at least one sensor comprises a pressure sensor and a flow sensor, inputs of the pressure and flow sensors facilitating recognizing malfunctions in the device.

18. In a drug pump device comprising a drug reservoir and a piston, responsive to pressure, for forcing a fluid out of the drug reservoir, a method of compensating for variations in friction affecting movement of the piston, the method comprising:

measuring a parameter indicative of a rate of drug delivery from the reservoir; and

based on the measurement, adjusting pressure on the piston so as to compensate for the variations in friction.