Electro-osmotic fluid delivery device and method
The present invention is directed to a fluid delivery device including a mechanism for decreasing the time required to achieve a constant fluid delivery rate. The fluid delivery device includes an electrochemical cell including a first half-cell and a second half-cell. A controller is operably connected to a first electrode positioned within the first half-cell and a second electrode positioned within the second half-cell. An ion-exchange member is positioned between the first half-cell and the second half-cell. A first reservoir contains a fluid to be delivered and, a displaceable member is positioned between the electrochemical cell and the reservoir, wherein movement of the displaceable member facilitates delivery of the fluid from the reservoir.
1 . A fluid delivery device, comprising:
an electrochemical cell including a first half-cell and a second half-cell;
a first electrode positioned within the first half-cell;
a second electrode positioned within the second half-cell;
a controller operably coupled to the first and second electrodes;
a means for decreasing the time to achieve a steady-state osmotic transfer;
an ion-exchange member positioned between the first half-cell and the second half-cell;
a first reservoir containing a fluid to be delivered; and,
a displaceable member positioned between the electrochemical cell and the reservoir, wherein movement of the displaceable member facilitates delivery of the fluid from the reservoir.
2 . The fluid delivery device of claim 1 , further comprising:
at least one protective porous separator or gel that is permeable to H 2 O molecules or saline, wherein the at least one protective separator or gel is positioned such that when the fluid delivery device being implanted within a body, at least one the electrodes or the ion-exchange membrane is not directly exposed to body tissue or body fluid.
3 . The fluid delivery device of claim 2 , wherein the protective porous separator is a second reservoir operably connected to the first half-cell, the second reservoir being a water or saline reservoir.
4 . The fluid delivery device of claim 2 , wherein the protective porous separator is a gel.
5 . The fluid delivery device of claim 1 , further comprising:
a housing wherein the first half-cell or the second half-cell being located outside of the housing.
6 . The fluid delivery device of claim 1 , further comprising:
a housing wherein the second half-cell and the ion-exchange member being located within the housing.
7 . The fluid delivery device of claim 1 , wherein the ion-exchange member is a cationic exchange membrane.
8 . The fluid delivery device of claim 7 , wherein the first electrode and the second electrode comprise zinc and silver chloride, respectively.
9 . The fluid delivery device of claim 1 , wherein the ion-exchange member is an anionic exchange membrane.
10 . The fluid delivery device of claim 9 , wherein the first electrode and the second electrode comprise silver chloride and zinc, respectively.
11 . The fluid delivery device of claim 1 , further comprising:
an electrolyte in electrical communication with the first electrode and the second electrode.
12 . The electro-osmotic cell according to claim 11 , wherein the electrolyte comprises a bodily fluid.
13 . The fluid delivery device of claim 1 , wherein the fluid contained in the first reservoir is a medicament.
14 . The fluid delivery device of claim 1 , wherein the displaceable member comprises a piston, bladder, bellows, diaphragm, plunger, or a combination thereof.
15 . The fluid delivery device of claim 1 wherein the means for decreasing the time to achieve a steady-state osmotic transfer includes:
the first half-cell having a first ionic concentration; and,
the second hall-cell having a pre-established ionic concentration greater than the concentration of the first half-cell,
wherein environmental osmosis between the first half-cell and the second half-cell is quickly established.
16 . The fluid delivery device of claim 1 wherein the means for decreasing the time to achieve a steady-state osmotic transfer includes a means for varying the current between the first and second half-cells.
17 . A method for decreasing the time to achieve constant fluid delivery rate in a fluid delivery device, the method comprising the steps of:
providing an electrochemical cell adjacent a fluid reservoir, the electrochemical cell including a first half-cell and a second half-cell, wherein the electro-osmotic cell facilitates delivery of a fluid from the fluid reservoir;
pre-loading the first half-cell with an electrolyte having a first ionic concentration; and,
pre-loading the second half-cell with an electrolyte having a second ionic concentration that is greater than the first ionic concentration of the first half-cell, wherein environmental osmosis between the first half-cell and the second half-cell is quickly established.
18 . A method for decreasing the time to achieve a constant fluid delivery rate in a fluid delivery device, the method comprising the steps of:
providing an electrochemical cell adjacent a fluid reservoir, the electrochemical cell including a first half-cell and a second half-cell, wherein the electro-osmotic cell facilitates delivery of a fluid from the fluid reservoir;
generating a first electrical current between the first half-cell and the second half-cell to achieve a steady-state osmotic transfer between the first half-cell and the second half-cell; and,
reducing the first electrical current in response to achieving a desired fluid delivery rate such that the fluid delivery rate is maintained constant.