FILL-STATUS SENSORS FOR DRUG PUMP DEVICES

• US 20110270188A1
• Filed: 04/20/2011
• Published: 11/03/2011
• Est. Priority Date: 04/20/2010
• Status: Active Grant

• Current Assignee: MiniPumps, LLC
• Original Assignee: MiniPumps, LLC
• Inventors: CAFFEY, SEAN, Tai, Yu-Chong, Li, Po-Ying, Brennan, Jeffrey
• Granted Patent: US 8,920,376 B2
• Time in Patent Office: Days
• US Class Current: 604/151
• 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

The filling status of a drug reservoir in a drug pump devices may be determined with mechanical and/or magnetic position sensor associated with a reservoir boundary.

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; and

a sensor for mechanically measuring a position of the piston inside the vial.

2. The device of claim 1, wherein the mechanical sensor comprises strings of different lengths connecting the piston to an opposed wall of the pump.

3. The device of claim 2, wherein the lengths of the strings are selected such that the strings successively break as the piston reaches successive specified positions inside the vial.

4. The device of claim 3, wherein the strings comprise or consist essentially of nylon.

5. The device of claim 3, wherein the strings comprise or consist essentially of metal.

6. The device of claim 5, wherein the strings form part of electronic circuits, breakage of the strings causing the circuits to generate an electronic signal.

7. The device of claim 3, wherein the vial is transparent, rendering breakage of the strings observable by eye.

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

9. The device of claim 1, further comprising a fill state indicator for causing an alert when the piston has moved by a predetermined distance.

10. A drug pump device comprising:

an electrolysis chamber formed between an adhesive patch and an expandable diaphragm;

a drug reservoir formed between the diaphragm and a dome disposed thereabove, generation of gas within the electrolysis chamber applying pressure to the diaphragm to force liquid from the drug reservoir;

a magnet associated with the diaphragm; and

a sensor associated with the dome for determining a relative distance between the magnet and a top of the dome.

11. The device of claim 10, further comprising a controller responsive to the sensor for controlling a rate of electrolysis based on the determined distance.

12. The device of claim 10, further comprising a fill state indicator for causing an alert when a predetermined threshold distance between the magnet and the top of the dome is reached.

13. The device of claim 11, wherein the sensor comprises an induction coil.

14. A drug pump device comprising:

an electrolysis pump chamber formed in an enclosure comprising an expandable portion, generation of gas within the electrolysis pump chamber creating pressure;

a secondary pump chamber located adjacent the electrolysis pump chamber and connected therewith by a fluid path, an upper surface of the secondary pump chamber being formed by a flexible diaphragm;

a drug reservoir formed between the flexible diaphragm and a dome disposed thereabove; and

a valve in the fluid path, the valve having a closed state that prevents fluid communication between the electrolysis and secondary pump chambers, thereby facilitating pressure buildup in the electrolysis pump chamber, and an open state that allows fluid communication between the electrolysis and secondary pump chambers so as to facilitate release of pressure from the electrolysis pump chamber to the secondary pump chamber, thereby causing drug to be expelled from the reservoir.

15. The drug pump device of claim 14, wherein the expandable portion of the enclosure of the electrolysis pump chamber comprises a flexible diaphragm.

16. The drug pump device of claim 15, further comprising a pressure sensor inside the electrolysis chamber.

17. 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; and

a sensor for capacitively measuring a position of the piston inside the vial.

18. The device of claim 17, wherein the piston comprises a material whose dielectric properties differ substantially from dielectric properties of a drug in the vial.