Dryers for removing solvent from a drug-eluting coating applied to medical devices

Patent metadata

Field	Value
Publication number	US-9909807-B2
Application number	US-201113235238-A
Country	US
Kind code	B2
Filing date	Sep 16, 2011
Priority date	Sep 16, 2011
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A coating device for coating a medical device with a drug-eluting material uses an in-process drying station between coats to improve a drug release profile. The drying station includes a dryer having a telescoping plenum which provides a shield and drying region for the stent or scaffold to reside while a heated gas is passed over the stent/scaffold. The shield and drying region improve efficiency in drying, predictability or drug release rate, uniformity of coating material properties lengthwise over the stent/scaffold and provide a platform that can effectively support stents that are over 40 mm in length.

First claim

What is claimed is:

1. A method for applying a composition to a stent, comprising the steps of:
spraying the composition on the stent; and
drying the stent, including the steps of
moving a drying region towards the stent or the stent towards the drying region to place the stent within the drying region, the drying region being surrounded by a shield having at one end an opening and, at an opposite end, a mouth of a dryer nozzle directly over or under the opening, wherein the stent or drying region is moved towards the other when the stent is over or under the mouth, and the stent passes through the opening when placed in the drying region,
drying the stent using a heated gas that passes through the nozzle and exits from the mouth at a gas velocity, passes over the stent while the stent occupies the drying region, and exits the drying region through the opening, wherein gas pressure produced by the heated gas prevents air external of the shield from being drawn into the drying region from the opening, and
after drying the stent, moving the drying region away from the stent or the stent away from the drying region.

2. The method of claim 1 , wherein the moving step includes the shield being raised or lowered when a mandrel supporting the stent is over or under, respectively, the shield to place the stent into the drying region.

3. The method of claim 2 , further including the step of disposing a proximal end and a distal end of the mandrel within alignment grooves of the shield, and rotating the mandrel when the drying gas is applied and the ends sit in the grooves.

4. The method of claim 1 , wherein the stent is supported on a mandrel, the drying step further including an actuator gripping a distal end of the mandrel when the stent is over or under the shield.

5. The method of claim 1 , wherein the moving step includes the step of expanding a plenum of the dryer to place the stent in the drying region.

6. The method of claim 1 , wherein a size of the opening is the same as a size of the mouth.

7. The method of claim 6 , wherein a housing of the nozzle comprises the shield.

8. A method for applying a composition to a stent, comprising the steps of:
spraying the composition on the stent;
moving the stent below or above a drying assembly, the drying assembly comprising a dryer nozzle and a shield, wherein
the nozzle comprises a mouth and internal diffusers,
the shield has a depth, and comprises a base and an opening separated from the base by the depth,
the opening is located directly below or above the base, and
the base is coupled to the mouth;

placing the stent within a drying region surrounded by the shield, wherein the stent passes through the opening when entering the drying region; and
while the shield surrounds the stent, drying the stent using a heated gas that exits from the dryer mouth, enters the drying region, and exits the drying region through the opening.

9. The method of claim 8 , further including supporting the stent above or below the assembly before the shield surrounds the stent.

10. A method for applying a composition to a stent, comprising the steps of:
spraying the composition on the stent;
moving the stent below or above a drying assembly including a shield coupled to a mouth of a dryer; and
while the shield surrounds the stent, drying the stent using a heated gas that exits from the dryer mouth wherein the moving step further includes increasing a length of a plenum of the drying assembly so as to surround the stent with the shield.

11. The method of claim 10 , wherein the drying assembly is a telescoping drying assembly.

12. The method of claim 8 , wherein a steady state gas flow rate is applied to the dryer when the composition is being sprayed on the stent such that a rate of solvent removal is substantially constant during when the stent is above or below the drying assembly including monitoring a gas temperature and if the gas temperature deviates from the drying temperature increasing or decreasing the gas temperature to maintain the steady state value.

13. The method of claim 8 , wherein gas passing through the nozzle is mixed by forcing the gas through the internal diffusers in order to produce a uniform property of the heated gas exiting from the nozzle mouth, wherein the uniform property is a gas temperature that varies over a length of the stent by less than 1 degree C.

14. The method of claim 11 , further including the step of retracting the telescoping dryer assembly, followed by spraying the composition on the stent a second time.

15. The method of claim 10 , wherein the shield has a first and second notch for receiving respective first and second portions of a mandrel located on opposite sides of the stent.

16. The method of claim 15 , wherein the stent and mandrel are rotating when the gas is applied.

17. The method of claim 1 , wherein the shield has a first and second notch for receiving respective first and second portions of a mandrel located on opposite sides of the stent.

18. The method of claim 1 , wherein the gas passing through the nozzle is mixed by forcing the gas through internal diffusers in order to produce a uniform property of the heated gas exiting from the nozzle mouth, wherein the uniform property is a gas temperature that varies over a length of the stent by less than 1 degree C.

Assignees

• Chen Yung Ming
• Gillick Matthew J
• Martins Michael T
• Papp John E
• Abbott Cardiovascular Systems Inc

Inventors

• Chen Yung Ming
• Gillick Matthew J
• Martins Michael T
• Papp John E

Classifications

• F26B9/003

  Small self-contained devices, e.g. portable · CPC title

• F26B25/066 Primary

  Movable chambers, e.g. collapsible, demountable (self-contained mobile devices, e.g. for agricultural produce F26B19/005) · CPC title