Osmotically driven dispense pump and related components for use in high pressure applications

Patent metadata

Field	Value
Publication number	US-9447781-B2
Application number	US-99645006-A
Country	US
Kind code	B2
Filing date	Jul 21, 2006
Priority date	Jul 22, 2005
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A high pressure osmotic dispense pump ( 10 ) having a substantially continuous delivery rate and extended delivery times is described and disclosed. The dispense pump ( 10 ) includes a semi-permeable membrane ( 12 ) which is substantially free of distortions and lateral stretching stresses. The membrane housing ( 14 ) and configuration of the present invention allows for consistent and accurate flow rates at the micro-liter level and improved control of the surface area of the semi-permeable membrane ( 12 ). This osmotic pump ( 10 ) also includes optional methods for activating and deactivating the osmotic process and/or controlling flow rates. Along with these features, the pump can be amplified or modulated to increase the dispense rate and/or adjust the flow rate during operation.

First claim

What is claimed is:

1. A high pressure osmotic dispense pump, comprising:
a) a semi-permeable membrane which is substantially free of distortions and lateral stretching stresses, said semi-permeable membrane oriented within a delivery chamber body, and being secured against longitudinal movement with respect to the delivery chamber body by lateral clamping between at least two housing members, said lateral clamping having only lateral forces with respect to a plane of the semi-permeable membrane so as to maintain the semi-permeable membrane substantially free of distortions and lateral stretching stresses, said housing members being secured against longitudinal movement with respect to the delivery chamber body;
b) a solvent reservoir oriented within the delivery chamber body, and in fluid communication with the semi-permeable membrane and including a solvent piston which is movable in response to a change in a fluid volume within the solvent reservoir;
c) a solution reservoir oriented within the delivery chamber body, and in fluid communication with the semi-permeable membrane and including a delivery piston which is movable in response to a change in a fluid volume within the solution reservoir;
d) a fluid reservoir oriented within the delivery chamber body, and adjacent the delivery piston opposite the solution reservoir and being fluidly isolated from each of the solvent reservoir and solution reservoir and having an outlet for dispensing a fluid contained in the fluid reservoir;
e) a flow channel between the solvent reservoir and the solution reservoir formed by the at least two housing members, wherein the cross sectional area of the semi-permeable membrane in the flow channel is substantially smaller than the cross sectional area of the solvent reservoir and the solution reservoir, wherein a diameter of the flow channel is less than half a diameter of the solvent reservoir and the solution reservoir; and
f) a spring oriented within the delivery chamber body, and operatively oriented adjacent the solvent piston opposite the solvent reservoir and configured to displace the solvent piston towards the semi-permeable membrane.

2. The pump of claim 1 , wherein each of the solvent reservoir, solution reservoir, and fluid reservoir have rigid walls.

3. The pump of claim 1 , wherein interior surfaces of at least one of the solvent reservoir, solution reservoir, and fluid reservoir include a coating of polytetrafluoroethylene.

4. The pump of claim 1 , wherein the pump is configured to deliver the fluid at a flow rate which is substantially continuous.

5. The pump of claim 1 , wherein the membrane is formed of a material selected from the group consisting of polyamide, porous glass, and cellulose acetate.

6. The pump of claim 1 , wherein the solvent piston and the delivery piston are formed of a material selected from the group consisting of polyether ether ketone, polyimide, polycarbonate, glass reinforced polytetrafluoroethylene, and composites or combinations thereof.

7. The pump of claim 1 , wherein the semi-permeable membrane has an exposed surface area and a covered surface area each oriented on a common side of the semi-permeable membrane, said exposed surface area being smaller than the covered surface area.

8. The pump of claim 1 , further comprising a support mesh oriented within the delivery chamber body, and oriented adjacent the semi-permeable membrane.

9. The pump of claim 1 , further comprising a modulator plate oriented within the delivery chamber body, and oriented between the semi-permeable membrane and the solvent reservoir, said modulator plate having a plurality of holes corresponding to a plurality of delivery flow rates.

10. The pump of claim 1 , further comprising a flow activation valve oriented within the delivery chamber body, and operatively connected between the solvent reservoir and the solution reservoir such that flow of a solvent across the semi-permeable membrane can be selectively controlled.

11. The pump of claim 10 , wherein the flow activation valve includes a cylindrical member having an open bore laterally therein such that a central axis of the open bore is substantially perpendicular to a central axis of the cylindrical member.

12. The pump of claim 11 , wherein the flow activation valve is oriented between the semi-permeable membrane and the solvent reservoir.

13. The pump of claim 1 , further comprising a delivery amplifier oriented within the delivery chamber body, and operatively connected to the delivery piston, said delivery amplifier having a first portion proximal to the fluid reservoir and a second portion distal to the fluid reservoir, said first portion having a larger cross-section than the second portion.

14. A method of forming a high pressure osmotic dispense pump as in claim 1 , comprising:
a) forming a flow channel in the at least two housing members wherein the flow channel in each housing member is substantially aligned and forms a fluid connection between a solvent reservoir and a solution reservoir; and
b) securing a semi-permeable membrane between the at least two housing members using substantially only securing forces which are perpendicular to the semi-permeable membrane.

15. The method of claim 14 , wherein the step of securing is performed by orienting the semi-permeable membrane between the at least two housing members and inserting at least two alignment members into corresponding alignment channels which are substantially perpendicular to the semi-permeable membrane such that the at least two housing members are pressed towards one another with substantially only forces acting perpendicular to the semi-permeable membrane.

16. The method of claim 14 , further comprising the step of coating an interior surface of at least one of the solvent reservoir, solution reservoir, and delivery reservoirs with a low friction material.

17. A method of dispensing a fluid using the pump of claim 1 , comprising:
a) charging the solvent reservoir with a solvent which is permeable to the semi-permeable membrane;
b) charging the solution reservoir with a solution of the solvent and a solute, said solution having a concentration of solvent which is lower than a concentration of solvent in the solvent reservoir; and
c) charging the fluid reservoir with a fluid to be dispensed through the outlet.

18. The method of claim 17 , wherein the pump is capable of operating at high pressures from about 100 psig to about 300 psig.

19. The method of claim 17 , wherein the solvent is water and the solution is aqueous sodium chloride.

20. The method of claim 17 , wherein the pump is capable of operating at a temperature up to about 150° C.

21. The pump of claim 1 , further comprising a gasket oriented between the at least two housing members and used to retain edges of the semi-permeable membrane, and maintain the membrane substantially free of distortions and lateral stretching stresses.

22. The pump of claim 1 , wherein the at least two housing members are discrete from, and secured from longitudinal movement within, the delivery chamber body surrounding the at least two housing members.

Assignees

• Deem Trent
• Ligrani Phil
• Hansen Bradley C
• Univ Utah Res Found

Inventors

• Deem Trent
• Ligrani Phil
• Hansen Bradley C

Classifications

• A61K9/0004

  Osmotic delivery systems; Sustained release driven by osmosis, thermal energy or gas · CPC title

• A61M5/145

  using pressurised reservoirs, e.g. pressurised by means of pistons · CPC title

• F04B17/00 Primary

  Pumps characterised by combination with, or adaptation to, specific driving engines or motors · CPC title

• A61M2005/14513

  with secondary fluid driving or regulating the infusion · CPC title

• F04B9/103

  having only one pumping chamber · CPC title