Fluid exchange apparatus for expandable port delivery system and methods of use

1. A device for injecting a therapeutic agent into an ocular implant, the implant being at least partially implanted in an eye, the implant further providing at least a first resistance to outflow of therapeutic agent into the eye, the device comprising:

an injection lumen configured to provide a pathway for injecting the therapeutic agent into the ocular implant;

an outlet lumen configured to provide a pathway through which pre-existing fluid in the ocular implant exits the ocular implant; and

a collection chamber fluidly coupled to the outlet lumen and operatively coupled to a first porous structure positioned within an annular element positioned near an upper end of the collection chamber forming a fixed upper limit of the collection chamber, the collection chamber configured to receive the pre-existing fluid that exits the ocular implant via the outlet lumen,

wherein the first porous structure of the collection chamber provides a first fluid outflow resistance to gas outflow and a second fluid outflow resistance to liquid outflow, wherein the first fluid outflow resistance is lower than the first resistance to outflow of the implant, and the second fluid outflow resistance is greater than a force imparted onto the implant by intraocular pressure of the eye, and

wherein injection of therapeutic agent into the ocular implant via the injection lumen causes the pre-existing fluid to exit the ocular implant and enter the collection chamber via the outlet lumen and causes a second pre-existing fluid to displace from the collection chamber.

2. The device of claim 1 , wherein the implant is expandable once implanted in the eye from a first, collapsed configuration to a second, enlarged configuration.

3. The device of claim 1 , wherein the implant comprises a second porous structure that provides the first resistance to outflow.

4. The device of claim 3 , wherein the first fluid outflow resistance of the first porous structure of the collection chamber is less than the first resistance provided by the second porous structure of the implant, and the second fluid outflow resistance of the first porous structure of the collection chamber is greater than the first resistance of the implant.

5. The device of claim 1 , wherein the second pre-existing fluid is a gas.

6. The device of claim 5 , wherein the gas is air.

7. The device of claim 6 , wherein the air is under vacuum.

8. The device of claim 1 , wherein the second pre-existing fluid is displaced from the collection chamber via a vent.

9. The device of claim 1 , wherein the second pre-existing fluid is displaced from the collection chamber via a valve.

10. The device of claim 3 , wherein the implant is expandable once implanted in the eye from a first, collapsed configuration to a second, enlarged configuration, wherein the first porous structure of the collection chamber prevents collapse of the implant away from the second, enlarged configuration after filling.

11. The device of claim 3 , wherein the first porous structure of the collection chamber is a hydrophobic membrane, a fabric, a porous fabric, a semipermeable membrane, an air permeable material, a moisture vapor transfer waterproof fabric, a hydrophilic porous material, or a porous sintered material.

12. The device of claim 3 , wherein the collection chamber is concentric with a longitudinal axis of the injection lumen.

13. A device for injecting a therapeutic agent into an ocular implant, the implant being at least partially implanted in an eye, the implant further providing at least a first resistance to outflow of therapeutic agent into the eye, the device comprising:

an injection lumen configured to provide a pathway for injecting the therapeutic agent into the ocular implant;

an outlet lumen configured to provide a pathway through which pre-existing fluid in the ocular implant exits the ocular implant; and

a collection chamber fluidly coupled to the outlet lumen and operatively coupled to a first porous structure, the collection chamber configured to receive the pre-existing fluid that exits the ocular implant via the outlet lumen,

wherein the first porous structure of the collection chamber provides a first fluid outflow resistance to gas outflow and a second fluid outflow resistance to liquid outflow, wherein the first fluid outflow resistance is lower than the first resistance to outflow of the implant, and the second fluid outflow resistance is greater than a force imparted onto the implant by intraocular pressure of the eye, and

wherein injection of therapeutic agent into the ocular implant via the injection lumen causes the pre-existing fluid to exit the ocular implant and enter the collection chamber via the outlet lumen and causes a second pre-existing fluid to displace from the collection chamber, wherein the collection chamber is a coiled tubular structure providing a uniform fill pattern that minimizes trapping of the second pre-existing fluid displaced from the collection chamber.

14. The device of claim 13 , wherein the collection chamber is offset relative to a longitudinal axis of the injection lumen.

15. The device of claim 14 , wherein the coiled tubular structure extends between an opening into the tubular collection chamber and terminates at the first porous structure.

16. The device of claim 15 , wherein the coiled tubular structure has a uniform inner diameter over a length of the coiled tubular structure.

17. The device of claim 15 , where the coiled tubular structure has an inner diameter that enlarges proximally to a second inner diameter.