# US 9,867,722 B2 · Apparatus and methods for filling a drug eluting medical device via capillary action

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- Number: US 9,867,722 B2
- Document ID: US9867722B2
- Status: Granted
- Kind: B2
- Application number: 14/926,590
- Filed: 2015-10-29
- Published: 2016-05-05
- Granted: 2018-01-16
- Earliest claimed: 2012-04-26
- Assignees: Medtronic Vascular, Inc.
- Applicants: Medtronic Vascular, Inc.
- Inventors: Justin Peterson; James Mitchell; Abby Schlichting; Nathanael Glucklich; Joseph Traina; Rajen Kumar
- Web page: https://patentgrep.com/patent/US9867722B2

## CPC

- A61F 2/82: Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents (stent-grafts for tubular structures of the body other than blood vessels A61F2/04; stent-grafts for blood vessels A61F2/07)
- A61F 2/915: with bands having a meander structure, adjacent bands being connected to each other
- A61L 31/16: Biologically active materials, e.g. therapeutic substances {(A61L31/047 takes precedence)}
- B05B 13/06: specially designed for treating the inside of hollow bodies (spray heads B05B1/00 - B05B7/00; {devices for covering leaks in pipes or hoses, e.g. hose-menders, from inside the pipe F16L55/162; sprayed layers of rubber or plastics for internal protection of pipes or pipe fittings against corrosion or incrustation F16L58/1027})
- A61F 2002/91541: {Adjacent bands are arranged out of phase}
- A61F 2002/91575: {connected peak to trough}
- A61F 2230/0054: V-shaped
- A61F 2240/001: Designing or manufacturing processes
- A61F 2250/0035: differing in release or diffusion time
- A61F 2250/0068: the pharmaceutical product being in a reservoir
- A61L 2300/416: Anti-neoplastic or anti-proliferative or anti-restenosis or anti-angiogenic agents, e.g. paclitaxel, sirolimus
- A61F: FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS (dental prosthetics A61C)
- A61L: METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES (preservation of bodies or disinfecting characterised by the agents employed A01N; preserving, e.g. sterilising, food or foodstuffs A23; preparations for medical, dental or toiletry purposes A61K)
- B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D)

## Abstract

Methods and apparatus are disclosed for filling a therapeutic substance or drug within a hollow wire that forms a stent. The stent is placed within a chamber housing a fluid drug formulation. During filling, the chamber is maintained at or near the vapor-liquid equilibrium of the solvent of the fluid drug formulation. To fill the stent, a portion of the stent is placed into contact with the fluid drug formulation until a lumenal space defined by the hollow wire is filled with the fluid drug formulation via capillary action. After filling is complete, the stent is retracted such that the stent is no longer in contact with the fluid drug formulation. The solvent vapor pressure within the chamber is reduced to evaporate a solvent of the fluid drug formulation. A wicking means may control transfer of the fluid drug formulation into the stent.

## Claims

### Claim 1

A method of filling a fluid drug formulation within a lumenal space of a hollow wire having a plurality of side openings along a length thereof that forms a medical device, the method comprising the steps of:
placing the medical device formed from a hollow wire having a plurality of side openings within a chamber that houses a fluid drug formulation and a means for wicking that is in contact with the fluid drug formulation, wherein the chamber is at or near the vapor-liquid equilibrium of a solvent of the fluid drug formulation;
placing a portion of the medical device into contact with the means for wicking such that at least one of the plurality of side openings is in contact with the means for wicking; and
maintaining contact between the means for wicking and the selected portion of the medical device until a lumenal space defined by the hollow wire is filled with the fluid drug formulation via capillary action through the at least one of the plurality of side openings in contact with the means for wicking, wherein the means for wicking is a plurality of beads.

### Claim 2 (depends on 1)

The method of claim 1, further comprising the steps of:
retracting the medical device such that the portion of the medical device is no longer in contact with the means for wicking; and
reducing a solvent vapor pressure in the chamber to evaporate a solvent of the fluid drug formulation.

### Claim 3 (depends on 2)

The method of claim 2, wherein the step of retracting the medical device such that the portion of the medical device is no longer in contact with the means for wicking removes excess fluid drug formulation from an exterior surface of the hollow wire during the step of retracting the medical device.

### Claim 4 (depends on 2)

The method of claim 2, wherein the step of reducing the solvent vapor pressure in the chamber includes venting the chamber back to ambient pressure.

### Claim 5

A method of filling a fluid drug formulation within a lumenal space of a hollow wire having a plurality of side openings along a length thereof openings that forms a medical device, the method comprising the steps of:
placing the medical device formed from a hollow wire having a plurality of side openings within a first chamber of an apparatus, wherein the apparatus includes a valve positioned between the first chamber and a second chamber that houses a means for wicking that is in contact with a fluid drug formulation and the valve is closed such that the first chamber and second chamber are not in fluid communication;
opening the valve such that the first chamber and second chamber are in fluid communication;
allowing the first and second chambers to reach solvent vapor saturation or near solvent vapor saturation;
placing a portion of the medical device into contact with the means for wicking within the second chamber such that at least one of the plurality of side openings is in contact with the means for wicking;
maintaining contact between the means for wicking and the selected portion of the medical device until a lumenal space defined by the hollow wire is filled with the fluid drug formulation via capillary action through the at least one of the plurality of side openings in contact with the means for wicking;
retracting the medical device such that the portion of the medical device is no longer in contact with the means for wicking and is located within the first chamber;
closing the valve such that the first chamber and second chamber are not in fluid communication; and
reducing a solvent vapor pressure in the first chamber to evaporate a solvent of the fluid drug formulation.

### Claim 6 (depends on 5)

The method of claim 5, wherein the step of allowing the first and second chambers to reach solvent vapor saturation includes atomizing droplets within the first and second chambers with an ultrasonic spray nozzle.

### Claim 7 (depends on 5)

The method of claim 5, wherein the step of allowing the first and second chambers to reach solvent vapor saturation includes increasing a temperature of the solvent.

### Claim 8 (depends on 5)

The method of claim 5, wherein the step of allowing the first and second chambers to reach solvent vapor saturation includes utilizing a fan to create convection across a reservoir filled within the solvent of the fluid drug formulation located within the first chamber.

### Claim 9 (depends on 5)

The method of claim 5, further comprising the step of:
allowing the first chamber to reach solvent vapor saturation or near solvent vapor saturation with the valve closed such that the first chamber and second chamber are not in fluid communication, wherein the first chamber houses a reservoir filled with the solvent of the fluid drug formulation and the step of allowing the first chamber to reach solvent vapor saturation is performed after the step of placing the medical device in the first chamber and prior to the step of opening the valve.

### Claim 10 (depends on 5)

The method of claim 5, wherein the step of retracting the medical device such that the portion of the medical device is no longer in contact with the means for wicking removes excess fluid drug formulation from an exterior surface of the hollow wire during the step of retracting the medical device.

### Claim 11 (depends on 10)

The method of claim 10, wherein the means for wicking is an open-celled sponge or foam.

### Claim 12 (depends on 10)

The method of claim 10, wherein the means for wicking is a plurality of beads.

### Claim 13 (depends on 5)

The method of claim 5, wherein the step of reducing the solvent vapor pressure in the first chamber includes venting the first chamber back to ambient pressure.