Abstract:
An apparatus for coating medical devices at the point of care with a polymer and/or therapeutic agent comprising an environmentally controlled device coating chamber in which the device may be delivered by the manufacturer as the device packaging, or the device may be placed into the chamber at the point of care. The environmentally controlled chamber can provide a sterile enclosure in which the polymer and/or a therapeutic agent can be applied to an uncoated or previously coated device and converted to another form (such as a liquid to a film or gel) if desired, under controlled and reproducible conditions. The environmentally controlled chamber can accommodate and provide for coating the device by immersion, spray and other methods of covering the device surface with a liquid or powder. The chamber can provide for energy sources, both internally, such as heat produced by film heaters, and externally, such as UV light or microwave passing through the enclosure. The chamber may allow for changes in atmosphere to affect the coating, such as the introduction of certain gases and introducing pressure or vacuum.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application No. 60/598,656 filed Aug. 4, 2004. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to the delivery of therapeutic agents from a coating, placed onto an implantable medical device at the point of care. More specifically, the present invention is directed to an environmentally controlled device coating and preparation chamber that facilitates the coating of a medical device with a drug and/or polymer coating at the point of care, prior to implantation into the body of a human or animal. 
       BACKGROUND OF THE INVENTION 
       [0003]    Coating the surface of implanted medical devices with polymers and/or therapeutic agents has become a common practice. In 2004, drug eluding coronary stents are expected to comprise more than half of the over four billion dollar worldwide stent market. Therapeutic agents can enhance the intended effect of the medical device, reduce or eliminate infection or inflammation related to the device, accelerate or improve acceptance of the device by the body, and/or treat specific diseases at the site of the device. 
         [0004]    Medical devices which are implanted into the human body and whose function can be enhanced by therapeutic coatings include artificial joints, fixation devices such as bone implants, artificial heart valves, pacemaker leads, dental implants and stents including cardiovascular, esophageal, and biliary. 
         [0005]    Polymers and coatings such as phosphorycholine, hydrogels and hydroxyapatite, with and without additional therapeutic agents, are commonly placed onto the surface of medical devices at the point of manufacture. While this practice delivers the device ready to use at the point of care, the coating and/or therapeutic agents are subjected to the device sterilization process and the rigors of handling, shipping and storage. Many therapeutic agents, such as proteins, cannot survive the device sterilization. Also, many therapeutic agents have relatively short shelf lives compared to the device itself, and when placed on the device at the point of manufacture, limit the shelf life and storage condition of the device. 
         [0006]    Larson et al., in U.S. Pat. No. 6,309,380, address the device point of manufacture therapeutic coating limitation problem by providing for application of the therapeutic coating at the point of care where and when the device is placed into the patient&#39;s body. This is accomplished by coating the device at the point of care immediately prior to implantation with a polymer and/or therapeutic agent and converting the coating to a film by a chemical process or energy source such as heat or UV light. Larson et al. do not provide for applying a coating and/or drug to the device at the point of care in a manner that reproducibly controls the device sterility and factors affecting variability of the coating, and subsequently the drug delivery after implantation of the device. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention is directed to an apparatus for coating medical devices at the point of care, such as in hospitals and medical clinics, for example, with a polymer and/or therapeutic agent. The invention provides for a point of care environmentally controlled device coating chamber (ECDCC) in which the device may be delivered by the manufacturer as the device packaging, or the device may be placed into the chamber at the point of care. The environmentally controlled chamber provides a sterile enclosure in which the solution containing polymer and/or a therapeutic agent can be applied to the device, and converted to a film if desired, under controlled and reproducible conditions. The environmentally controlled chamber of the invention can accommodate and provide for coating the device by immersion, spray and other methods of covering the device surface with a liquid or powder. The chamber of this invention can provide for energy sources, both internally, such as heat produced by film heaters, and externally, such as light (e.g. UV) or microwave passing through the enclosure. The chamber may allow for changes in atmosphere to affect the coating, such as the introduction of certain gases and introducing pressure or vacuum. In addition, the present invention provides for an electronically, and/or manually, controlled machine (hereafter called a “docking station”) which can be used to electro-mechanically, and/or manually, hold, position, and/or manipulate an ECDCC for the purpose of mixing medical device coating materials, introducing one or more substances into an ECDCC, and/or otherwise controlling the environment for, and/or the process of, the application of therapeutic, and/or other substances to one or more medical devices within an ECDCC. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  illustrates the operator&#39;s panel and display of a docking station. 
           [0009]      FIG. 2  shows the docking station side door and chamber process area with door in closed position. 
           [0010]      FIG. 3  shows a view of the drive means end of the docking station chamber process area. 
           [0011]      FIG. 4  shows a view of the tailstock end of the docking station chamber process area. 
           [0012]      FIG. 5  illustrates a cylindrical-shaped device coating chamber viewed from a coating process end. 
           [0013]      FIG. 6  illustrates a cylindrical-shaped device coating chamber viewed from a mixing process end. 
           [0014]      FIG. 7  represents a view into the interior of the coating process end of a cylindrical-shaped device coating chamber. 
           [0015]      FIG. 8  illustrates a mixing basket portion of a cylindrical-shaped device coating chamber. 
           [0016]      FIG. 9  illustrates a mixing drive shaft and stopper from the mixing basket of  FIG. 8 . 
           [0017]      FIG. 10  shows a medical device attached to an interior surface of the coating process end of a cylindrical-shaped device coating chamber. 
           [0018]      FIG. 11  illustrates a cylindrical-shaped device coating chamber positioned in a docking station for mixing of a coating. 
           [0019]      FIG. 12  illustrates a cylindrical-shaped device coating chamber positioned in a docking station for coating a medical device. 
           [0020]      FIG. 13  is a view of a side and drive attachment end of an immersion coating chamber. 
           [0021]      FIG. 14  shows introduction ports of an immersion coating chamber. 
           [0022]      FIG. 15  illustrates the magnetic drive mixer and mixing reservoir of an immersion coating chamber. 
           [0023]      FIG. 16  illustrates the interior of the main body portion and immersion reservoir of an immersion coating chamber. 
           [0024]      FIG. 17  shows a medical device support cover for attachment to an immersion reservoir of an immersion coating chamber. 
           [0025]      FIG. 18  illustrates an immersion coating chamber positioned in a docking station for mixing of a coating. 
           [0026]      FIG. 19  illustrates an immersion coating chamber positioned in a docking station for coating a medical device. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0027]    Coating a medical device with a therapeutic agent at the point of care requires a process and procedure which delivers a reproducibly and controlled dose of the therapeutic agent and a coating which has reproducible adhesion and mechanical properties. The coating process must be done in a manner which preserves the sterility of the device, coating polymer and/or therapeutic agent. The application of energy to facilitate the formation of coatings must be done in a manner that is uniform, reproducible and does not degrade the therapeutic agent. In addition, the placement of therapeutic agents onto the device at the point of care cannot be technique dependent nor require specialized skill or unusual attention by attending medical personnel. It is anticipated that many point of care device coatings, intended to provide a therapeutic effect and enhance the action of the device, will be applied to the device during or immediately prior to a surgery or other invasive procedures. 
         [0028]    As stated above, the present invention is directed to an apparatus for coating medical devices, such as with a polymer and/or therapeutic agent, at the point of care. The invention provides for a coating chamber which is positionable in a docking station. The environmentally controlled device coating chamber may contain a port for adding the coating material (while maintaining sterility of the device, chamber and solution) and a heater to provide temperature controlled heat for the film formation process. it may also contain a stirring means (e.g. a magnetic field driven stirrer) for thoroughly mixing the polymer and the therapeutic agent prior to the coating process. A second heater may be contained in the base of the coating chamber for heating the coating solution to a specific temperature before the coating process begins. The coating chamber can incorporate a reservoir, with or without a one-way valve, to trap excess polymer and/or therapeutic liquid or powder during and after the coating process. The coating chamber can be fabricated from materials such as certain plastics, which provide for the passage of UV light and/or microwave energy to facilitate film formation. 
         [0029]    The coating chamber can be received by a docking station that can provide timed and controlled energy (light, microwave, etc.) or electrical power to the device, and a timed rotating magnetic field to drive the magnetic stirrer incorporated in the coating chamber and timed and controlled rotation of the coating chamber to facilitate complete and uniform distribution of the solution or powder on the device. 
         [0030]      FIGS. 1-4  illustrate one aspect of the present invention comprising a docking station  2  into which various coating chambers (described below) are positionable for coating of a medical device. The docking station  2  ( FIG. 1 ) includes an operator&#39;s panel comprising an on-off switch  4 , bar code reader  6 , chip reader  8 , swipe card reader  10  and indicator lights  12 . A mechanism to read information stored on a computer disc may also be included. A groove  14  is provided in the docking station chassis  15  for a rollup door (shown with door “open”) and an electronically controlled rollup door latch  16 ,  17  ( FIG. 3 ) restricts and/or controls coating processes so that the door remains closed during processing. A touch screen interactive display  18  receives feedback, such as from an internal level detector, and provides for an interactive readout such as from an out-of-level system lock. 
         [0031]    As best seen in  FIG. 2 , the docking station  2  preferably includes a piano-style side door hinge  20 , side door  22  and door latch  24 , preferably electronically controlled. Further included is a rollup door  26  (closed position) enclosing a coating chamber process area  28  ( FIGS. 3 and 4  with door  26  open) having one or more, preferably three, reflective interior surfaces  30  and one or more bulbs or other devices  32  for introducing light, heat and/or microwave radiation to the chamber  28 . 
         [0032]      FIGS. 3 and 4  also show the chamber process area  28  having a horizontally mounted magnetic coating mixer drive unit  34 , a vertically mounted magnetic coating mixer drive unit  36  (one or both drive units  34 ,  36  may be present) and a computer controlled docking station drive head  38  for rotating various styles of medical device coating chambers for coating processes. Drive head  38  includes a drive socket  40 , for engaging a cylindrical-style chamber mixing drive knob to spin the mixer, and a plurality of introduction ports  42  (six shown) which match those in a coating chamber and allow the docking station to automatically introduce pressure, special gases, and/or other elements into the chamber before, during, and/or after a coating is applied to a medical device. Docking station chassis  15  houses drive motors, electronics, etc. Drive head  38  and drive socket  40  may both be driven by a single motor or may each be driven by a separate motor. A coating chamber supporting tailstock  44  is also included as shown in  FIG. 4 . 
         [0033]      FIG. 5  illustrates a cylindrical-shaped device coating chamber  50  (viewed from a coating process end portion  55 ) which is positionable in a docking station  2  ( FIGS. 3 and 4 ). The coating chamber  50  comprises a chamber cylinder  51  having at one end thereof a support cover  52  with an area of outside diameter  53  of the support cover  52  having a bayonet-style attachment mechanism (not shown), or other positive-attachment means, which is configured to mate with the drive head  38  of the docking station. Also located at one end of the chamber cylinder  51  are a plurality of introduction ports  54  (six shown) in coating floor  59  for controlling the atmosphere, introducing gases and/or other elements into the coating chamber before, during, and/or after a coating is applied to a medical device. 
         [0034]    The coating chamber  50  further includes a rotary door  56  which opens and closes the introduction ports, either automatically or manually, such as with a manual rotary door latch roll  58  which lifts up to be moved from an “open” to a “closed” position and back. Preferably, a manual rotary door latch roll spring  60  is mounted in a rotary door control tab  62  for holding the manual rotary door latch roll  58  against docking station support cover  52  and in the “open position” and “closed position” grooves  64 ,  66  respectively, when the manual rotary door latch roll  58  is not pulled up/away by pulling on control tab  62  which moves between grooves  64 ,  66  via slot  61 . In  FIG. 5 , the manual version is shown with the rotary door  56  in the “open” position. Of course, rotary door  56  may be opened and closed by any suitable automatic means. Alternatively, each control port  54  may individually be opened and closed either my manual or automatic means.  FIG. 5  also shows the chamber  50  having a filtering pressure limiting vent port cover  68  having internal threads to attach to any filtering pressure limiting vent port, attached via boss  70  to the coating chamber  50 , on any style of medical device coating chamber. 
         [0035]    The other end of chamber cylinder  51  (mixing process end portion  57 ) includes a chamber mixer attachment cover  72  which holds a chamber mixer assembly in the mixing end of the chamber cylinder. Attachment cover  72  has internal threads (or other positive-attachment means) which attach it to the chamber cylinder  51  and preferably includes an external bayonet-style attachment mechanism (not shown), or other positive-attachment means, on outside diameter  74  of chamber mixing attachment cover  72  which allows attachment to the drive head  38  of the docking station  2  during a mixing process. Cover  72  may include a large access hole (not shown) to allow manual (or automated) loading and emptying of a chamber mixing basket ( FIG. 8 ). 
         [0036]    Both ends of the chamber cylinder  51  have a raised shoulder  76  with external threads (or other positive-attachment means) which engage with internal threads (or other positive-attachment means) of docking station support cover  52  on the coater end of the chamber  50 , and with internal threads (or other positive-attachment means) of the chamber mixer attachment cover  72  on the mixer end  57  of the chamber  50 . 
         [0037]      FIG. 6  illustrates the cylindrical-shaped device coating chamber  50  viewed from its mixing process end portion  57  which includes a floor  78  of the mixing basket, mixer drive shaft  80  and drive knob  82  which engages drive socket  40  of the docking station  2  ( FIG. 3 ) when the coating chamber  50  is positioned in the docking station  2  for mixing ( FIG. 8 , discussed below). Mixing process end  57  also preferably includes one or more, preferably two, syringe port covers  84 ,  86  having internal threads (or other positive attachment) to attach to any syringe port on any coating chamber. In  FIG. 6 , syringe port cover  84  comprises a needle penetration membrane and syringe port cover  86  is without a needle penetration membrane. Preferably all syringe ports have an electrical contact such that when the cover is replaced with a screw-in (or other positive attachment) syringe, a foil heater and/or temperature sensor in the syringe can receive electrical power and/or computer control. 
         [0038]      FIG. 7  represents a view into the interior of the coating process end portion  55  of a chamber cylinder  51 . A plurality (six are shown) of coating vanes  88  are spaced, preferably equidistantly, about the interior surface of the coating process end of the chamber cylinder  51 . The coating vanes  88  lift a portion of coating mixture from bottom of the chamber as it rotates in the docking station, and the coating mixture bathes, drips or splashes onto a medical device, coating it evenly. A leveling mechanism on the docking station insures the device is coated evenly. A foil heater  90  with temperature sensor (such as the Thermofoil Heater/Sensor manufactured by Minco Products of Minneapolis, Minn.) may also be included. An internal opening  71  communicating with the filtering pressure limiting vent port is also shown. 
         [0039]    The mixing process end portion  57  of coating chamber  50  is further illustrated in  FIG. 8 . A mixing basket is formed by floor  78 , basket cylinder  92 , shoulder portion  94  and delivery end  96 . The mixing basket is held in place in the chamber cylinder  51  by attachment cover  72  ( FIG. 6 ). The inner surface of the basket cylinder  92  includes mixing vanes arranged thereon. Delivery end  96  is opened and closed by a stopper  98 , preferably conical in shape, which is actuated by axial movement of mixer drive shaft  80  ( FIG. 9 ) that extends between the drive knob  82  and the stopper  98 . Preferably, a spring (not shown) is placed between the floor  78  and the base  83  of the drive knob  82  whereby the force of the spring urges the drive knob  82  away from floor  78  (to the right in  FIG. 8 ) thereby also urging stopper  98  into sealing engagement with the end of delivery end  96 . Preferably, the distal portion of delivery end  96  is shaped so as to be complimentary with the form of the stopper  98  (e.g. both are conical) such that an adequate seal is, formed upon contact. 
         [0040]    As seen in  FIG. 9 , preferably the drive shaft  80  includes a means such as a spring pin  85  that cooperates with the appropriate detent surfaces on the inner surface of floor  78  to control the position of stopper  98 . For example, clockwise rotation of drive knob  82  may result in the spring pin  85  encountering a stop surface. Further clockwise rotation of the drive knob  82  thereby results in the rotation of the entire mixing basket as would be the case during the mixing process when the drive knob  82  is engaged with the drive socket  40  of docking station  2 . However, the clockwise movement of the spring pin  85  imparts no movement of the drive shaft in the axial direction (the direction on the drive shaft  80 ) and thus, the stopper  98  remains closed against the delivery end  96  by the action of the spring against the shoulder  83 . 
         [0041]    On the other hand, counterclockwise rotation of the drive knob  82 , such as turning by hand, may result in the spring pin  85  encountering a surface that inwardly tapers (i.e. toward delivery end  96 ) to a stop surface. Movement of the spring pin  85  along the tapered surface results in the drive shaft  80 , and hence the stopper  98 , moving to the left in  FIG. 8  against the force of the spring, thereby causing the stopper  98  to disengage its seal with delivery end  96  and allow the contents of the mixing basket to flow out and into the coating end  55  of the coating chamber  50 . 
         [0042]      FIG. 10  shows an interior view of support cover  52 , having interior surface  100 , which together with the chamber cylinder  51  forms the coating process end  55  ( FIG. 5 ). The interior surface of floor  59  includes a boss  102  and device attachment means  104  which is of a form appropriate for the particular device that is to be coated. In  FIG. 10 , the device shown is a prosthetic hip  106 . 
         [0043]      FIG. 11  illustrates a coating chamber  50  positioned in a docking station  2  for mixing to occur in the mixing process end  57  of the coating chamber. The drive knob  82  would be turned in the appropriate direction so that the stopper  98  was closed against delivery end  96  and the desired components would be introduced through one or both ports  84 ,  86  ( FIG. 8 ). The coating chamber  50  is then positioned in the docking station  2  by inserting the drive knob  82  into drive socket  40  and placing the support cover  52  in tailstock  44 . The drive socket  40  is then rotated causing rotation of the coating chamber  50  (and, hence, rotation of the mixing basket) thereby mixing the components previously placed in the mixing basket. The rotational speed and duration are adjustable and are based on the components and mixing requirements. 
         [0044]    Once mixing is complete, the coating chamber  50  is removed from the docking station  2  and preferably positioned vertically with the mixing end  57  “up”. Drive knob  82  is then rotated as appropriate to open the stopper  98  (as discussed above) thereby resulting in the coating mixture flowing from the mixing basket into the coating process end  55  of the coating chamber  50 . 
         [0045]    After allowing an appropriate amount of time for emptying of the mixing basket, the drive knob  82  is turned in a reverse direction to close the stopper  98  and the coating chamber  50  is returned to the docking station  2  and positioned such that the coating process end portion  55  is engaged with the drive head  38  and mixing process end portion  57  is engaged with tailstock  44  as is shown in  FIG. 12 . Drive head  38  is rotated, at a desired speed and for a desired time, thereby rotating the coating chamber  50  (and therefore, of course, the coating process end  55 ). The coating vanes  88  ( FIG. 7 ) lift a portion of coating mixture from bottom of the chamber as it rotates in the docking station  2 , and the coating mixture bathes, drips or splashes onto a medical device (such as an artificial hip shown in  FIG. 10 ), coating it evenly. At an appropriate time before, during and/or after coating, introduction ports  54  may be utilized for controlling the atmosphere, introducing gases and/or other elements into the coating chamber. 
         [0046]    Additionally, heat (or other energy necessary for curing, for example) may be introduced at a desired time from within the coating process end  55  such as by heater  90  ( FIG. 7 ) or via a source from within the chamber  28  of docking station  2  ( FIG. 3 ). Polymerization can be initiated by the docking station  2  by applying energy (light or microwave), filtered and/or heated air through a chamber port, or electricity to heating foils internal to the chamber. Coating chamber  50  may be fabricated from plastic through which light and/or microwave energy readily passes. Coating chamber  50  may have a medical device installed therein as part of its manufacturing process (hence, medical device is “packaged” in the coating chamber) or a medical device may be installed at the point of coating. 
         [0047]    While  FIGS. 6-12  illustrate a bath, splash or drip type of coating chamber,  FIGS. 13 and 14  disclose an immersion coating chamber  110  (which may be fabricated from plastics through which light and/or microwave energy may readily pass) comprising a generally cylindrical shaped main body portion  112  having a first end  113  closed by a wall  114  and a second end closed by a wall  116  which may be removable. Alternatively, first end  113  may be closed by a removable cover which, upon removal, exposes a floor with introduction ports (similar to floor  59  and ports  54  in  FIG. 5 ) to align with ports  42  of the docking station  2  when the coating chamber  110  is positioned in the docking station  2 . The area adjacent the first end preferably includes an attachment mechanism  118  such as a bayonet-style attachment mechanism (or other positive-attachment means) for engagement with the drive head  38  of a docking station  2  ( FIG. 3 ). 
         [0048]    Wall  116  preferably includes one or more ports with covers ( FIG. 14 ) such as syringe port cover with needle penetration membrane  120 , syringe port cover without needle penetration membrane  121  and filtering, pressure-limiting vent port cover  122 . All covers have internal threads (or other positive attachment) to attach to any respective port on any device coating chamber. All syringe ports have an electrical contact such that, when the cover is replaced with a screw-in (or other positive attachment) syringe, a foil heater and temperature sensor in the syringe can receive electrical power and/or computer control. 
         [0049]    Immersion coating chamber  110  further includes a magnetic drive mixing reservoir portion  124  which houses a magnetic drive mixer. The mixing reservoir  124  is closed by a cover  126  which preferably has internal threads (or other positive-attachment means) and which seals against the face of mixer reservoir  124 . Located preferably diametrically opposite of mixing reservoir  124  is an immersion reservoir portion  128  which houses an internal, electrically powered foil heater with temperature sensor. Immersion reservoir  128  is dosed by a medical device support cover  130  which preferably has an electrical connection, internal threads (or other positive-attachment means) and which seals against the face of immersion reservoir  128 . Medical device support cover  130  supports and positions a medical device (such as a prosthetic heart valve or cardiovascular stent) on a medical device attachment means and preferably includes an internally mounted, electrically powered hotwire coating trimmer. 
         [0050]    In  FIG. 15 , magnetic drive mixing drive cover  126  is removed to show the interior  132  of the magnetic drive mixing reservoir  124  and the magnetic drive mixer  134 . Interior  132  may include a foil heater. Also visible through first end  113  (open, with alternative cover removed and showing location  117  of floor with introduction ports), and through the interior  115  of main body portion  112 , is a medical device  136  (prosthetic heart valve shown) mounted to medical device support cover  130  via attachment means  138 . An electrically powered and controlled foil heater with temperature sensor  140  is shown positioned in the immersion coating reservoir  128 . 
         [0051]    In  FIG. 16 , the medical device support cover  130  is removed from the immersion reservoir  128  to show the interior  142  of the immersion reservoir. As appropriate, the inside of the immersion coating reservoir  128  can be configured (such as with a recess and shoulder  144 ) so as to accommodate a particular medical device support structure and attachment means. 
         [0052]      FIG. 17  shows a medical device support cover  130  comprising an area of internal threads  146  (or other positive-attachment means) for attachment to immersion reservoir  128 . As stated above, support cover  130  includes medical device attachment means  138  to which is attached medical device  136  (prosthetic heart valve shown), an electrically powered and controlled hotwire coating trimmer  148  and a boss  150  for positioning the medical device attachment means  138  and hotwire coating trimmer  148  within the coating reservoir  128 . An immersion chamber  110  may have a medical device installed therein as part of the manufacturing process or a medical device may be installed at the point of coating. 
         [0053]      FIG. 18  shows the immersion coating chamber  110  positioned in a docking station  2  whereby attachment mechanism  118  is engaged with drive head  38 . The coating chamber  110  is oriented by the drive head  38  such that magnetic drive mixing drive cover  126 , and hence, magnetic drive mixer  134  are positioned adjacent magnetic coating mixer drive unit  34  ( FIG. 3 ) whereby upon activation of mixer drive unit  34 , components such as polymers and/or therapeutic agents previously supplied to the mixing reservoir  124  will be appropriately mixed in accordance with instructions provided to the controller of the docking station  2 . 
         [0054]    Upon completion of the mixing, the drive head  38  is activated to rotate the immersion chamber  110  by 180 degrees to the position shown in  FIG. 19  wherein the prepared coating residing in mixing reservoir  124  flows into the smaller immersion coating reservoir  128  to immerse the medical device supported on cover  130  in the coating. After a predetermined amount of time, the immersion chamber  110  is again rotated by drive head  38  to a position (such as back to the position shown in  FIG. 18 ) whereby the coating can drain from the medical device and from the immersion coating reservoir  128  back into the mixing reservoir  124  thereby leaving a film on the medical device whose thickness is controlled by the surface tension, density and viscosity of the coating. Additionally, heat (or other energy necessary for curing, for example) may be introduced at a desired time from within the immersion coating reservoir  128  such as by foil heater  140  or via a source from within the chamber  28  of docking station  2  ( FIG. 3 ). After the coating process is complete, the support cover  130  can be removed, providing access to the coated device. 
         [0055]    Cured polymer flash adhering to device support can be addressed by the electrically powered and controlled hotwire coating trimmer  148 . After the polymer film has been formed and polymerized or cured, the docking station can energize the resistance wire to bum off the polymer film at the support member contact points. Additionally, cured polymer adhering to the chamber and adhering the chamber lid to the body may be addressed by equipping the docking station with a wrench type mechanism (not shown) into which the chamber lid can be inserted to assist the medical personnel in disconnecting the chamber body from the lid. 
         [0056]    In its simplest form, an immersion coating chamber may have the shape of a cone, pyramid or trapezoid. The important aspect being that the mixing reservoir is of a size to hold sufficient coating mixture such that upon inverting the immersion chamber, the coating mixture will flow into the coating reservoir and immerse the device to be coated. Of course, it should be understood that if mixing of coating constituents is not necessary, the coating composition may be introduced directly into the coating process portion of a coating chamber (e.g. coating process end portion  57  or immersion coating portion  128 ). 
         [0057]    In operation, the individual operating the docking station  2  and the immersion coating chamber  110  (including an implantable medical device that was attached to cover  130  by the manufacturer, or alternatively, attached to cover  130  at the point of care), following interactive instructions on the touch screen  18  of the docking station  2 , would install the immersion chamber in the docking station  2  by attaching the chamber opening  113  to the docking station drive head  38  ( FIG. 18 ) via attachment mechanism  118 . Next, the operator would initiate a “coating ingredient loading cycle”, and the docking station  2  would position the immersion chamber  110  so that its magnetic coating mixer  134  (and mixing reservoir  124 ) is down and its medical device coating reservoir  128  is up. Next, the operator would utilize the syringe ports  120  and/or  121  to deposit a pre-determined set of coating ingredients into the coating chamber. Following that, the docking station rollup door would need to be closed to then initiate the “coating mix cycle” by the magnetic mixer. When mixing is complete, the docking station may pause until the operator has initiated the “medical device coating cycle”, during which docking station drive head  38  would rotate the coating chamber 180 degrees to immersion-coat the implantable medical device ( FIG. 19 ). The coating chamber  110  would then be rotated back to the original position and, possibly, the hot-wire coating trimmer may be activated. After the coating is cured, the docking station  2  may direct the rotation of the immersion coating chamber about 45 degrees so that the support cover  130  with the coated medical device attached could be removed from the immersion coating chamber, and so that the coated medical device could then be removed from the cover and implanted. 
       EXAMPLE 1 
     Artificial Knee or Hip (an Orthopedic Implant) 
       [0058]    The device is coated at the point of manufacture with Hydroxyapatite (HAp), a naturally derived material that makes up bone mineral and the matrix of teeth. Hydroxyapatite is biocompatible and can be coated onto the surface of a medical device with porous properties that support the absorption of therapeutic agents and their subsequent delivery after the device is implanted. The porous Hydroxyapatite coated medical device is sterilized and delivered to the point of care in the chamber. An alternative bonding/linking technology for this example is to coat the device at the point of manufacture with a linker technology which bond functional peptides to biological materials and to synthetic materials. Linker technology is available from, for example, Affinergy Inc., Research Triangle Park, N.C. A therapeutic protein to initiate a biological function related to the bone is added through the injection ports, mixed thoroughly in the chamber if required, heated to reduce their viscosity if required after which the chamber rotates and bathes the device in therapeutic agent for sufficient time, controlled by the docking station, such that the therapeutic agent is absorbed by the Hydroxyapatite coating or linked to the functional peptide. The docking station can then stop rotation and bathing of the device, allow for sufficient time for the device to drain, blow off excess therapeutic agent and dry the surface if desired, having maintained a sterile atmosphere throughout the process. This process allows for the delivery of a therapeutic protein that may not have survived sterilization and would have limited shelf life had it been applied at the point of manufacture. 
       EXAMPLE 2 
     (Heart Valve) 
       [0059]    A prosthetic heart valve is delivered, sterile, in an immersion chamber. At the point of care, an in vivo biocompatible and biodegradable polymer, such as one produced from star shaped polylactide containing an ethoxylate core and functionalized with acrylate and methacrylate pendant groups, is injected into the chamber at the point of care. This polymer system is selected because of the ability to activate it with light and change from a soft structure to a strong mechanical structure that can withstand the flow and pressure of blood in the heart. A therapeutic agent, such as an antimicrobial peptide is added either in conjunction and mixed with the polymer or in a separate step. The docking station then controls a process for mixing the polymer and therapeutic agent, inverts the chamber through rotation such that the unmasked heart valve suture ring is saturated with the polymer/therapeutic agent solution. After allowing sufficient time for absorption into the suture ring and/or the coating of the suture ring surface, the docking station then inverts the chamber such that the heart valve now drains of excess coating. After sufficient time for complete drainage, the docking station turns on the light source for a timed cure of the polymer then energizes the hot wire at the implantable device attachment points to bum of excess flash coating. The device has now been coated with an in vivo biodegradable coating containing a protein based therapeutic agent. 
       EXAMPLE 3 
     (Cardiovascular Stent) 
       [0060]    A cardiovascular stent is coated at the point of manufacture with Hydroxyapatite or a linker technology such as that offered by Affinergy, Inc. of Research Triangle Park, N.C., for example, and delivered to the point of care sterile in the shipping/coating chamber. At the point of care, a therapeutic agent to inhibit restenosis such as the VEGF receptor KDR/flk-1 is added through the injection port of the chamber. Therapeutic agents such as KDR/flk-1 have advantages over proliferation inhibiting drugs in that peptides and proteins such as KDR/flk-1 prevent restenosis by accelerating the re-establishment of the proliferation down-regulating endothelial tissue. Sterilization and shelf life limitations make difficult the application of peptides, proteins and biological therapeutic agents at the point of manufacture. The chamber containing the therapeutic agent and the stent is inserted into the docking station which, by reading bar codes and/or imbedded chips, confirms the correct stent, coating and therapeutic agent then inverts the chamber through rotation such that the hydroxyapatite stent coating or the functional peptide linker is saturated with the therapeutic agent. After allowing sufficient time for absorption into the stent coating or attachment to the functional peptide linker, the docking station then inverts the chamber such that the stent now drains of excess coating. 
       EXAMPLE 4 
     (Heart Valve) 
       [0061]    A heart valve is coated with functional peptide linker such as that developed by Affinergy, Inc. of Research Triangle Park, N.C., at the point of manufacture. Affinergy&#39;s functional peptide linker utilizes two custom peptides linked together, one of which can selectively bind to synthetic materials such as the sewing ring material (Dacron) of the heart valve and the other to a biological material (biologic). The coated heart valve is sterilized and delivered to the point of care. 
         [0062]    While pre-coating a medical device prior to application of a final coating of a polymer and/or therapeutic agent has been discussed above with respect to linking, binding and absorbing types of pre-coatings, adsorbing types of pre-coatings, such as ion attracting types of coatings, are also contemplated as pre-coating compositions. 
         [0063]    At the point of care, a biological therapeutic agent which accelerates or stimulates the natural healing process and the production of endothelial cells may be added. Examples of biologics for accelerating the formation or collection of endothelial cells include an antibody specific to the antigen cells that are in the blood which captures the patients circulating endothelial progenitor cells in order to accelerate the natural healing process. This antibody is available from BioInvent International AB of Lund, Sweden and has been developed for cardiovascular stents by Orbus Medical Technology of Fort Lauderdale, Fla. A second example of a Biologic which can be attached to the heart valve at the point of care, using the previous described peptide linker technology is the VEGF receptor KDR/flk-1 which is rate-limiting for a fast regeneration of the endothelium resulting in an acceleration of the natural healing process. 
         [0064]    In this example of a point of care applied biologic, the invention device described for applying a coating and therapeutic agent at the point of care is not needed as the biologic can be attached to the peptide linker at the point of care by means such as direct immersion into a container for a short non critical period of time 
         [0065]    The present invention also contemplates a chamber of any shape which utilizes atomized liquid or spray droplets to coat a device. The atomized particles can be produced by an ultrasound transducer in the base of a chamber, or in the docking station and acoustically coupled to the chamber or by ultrasound atomizing nozzles, such as those manufactured by Sono-Tek Corporation in Milton, N.Y., in the chamber or in the docking station. Atomization can be accomplished in a contained atmosphere, thereby eliminating the hazard of airborne polymer and therapeutic agents. Spray droplets can be produced by pressurized gas delivering polymer and/or therapeutic agents to spray nozzles distributed throughout the chamber. A filter and/or filter collection chamber on the chamber collects the polymer and therapeutic agent, thus preventing their release into the atmosphere. 
         [0066]    Polymer and/or therapeutic agents can be applied as atomized or spray droplets in specific metered amounts (such as with equipment supplied by Sono-Tek) or in excess whereby the excess is allowed to drain off the device, in which case, the coating thickness and drug delivery are controlled by the solution viscosity, density, surface tension and the chamber internal temperature. 
         [0067]    Polymer and/or therapeutic agents can be conveniently added to a chamber at the point of care utilizing pre-filled syringes. A syringe with multiple barrels of the same or different diameters can be pre-filled with the polymer and therapeutic agent to be added at the point of care to the chamber. If a chemical reaction is required to cure the polymer, a three-chamber syringe can be provided with two chambers dedicated to the polymer system and the third to the therapeutic agent. If a chemical reaction is not required to cure the polymer, a two chamber syringe can be provided with one chamber dedicated to the polymer and one to the therapeutic agent. The barrel(s) dedicated to the polymers can be equipped with a one-way check valve so that the user may draw up the therapeutic agent into that dedicated chamber only. The syringe may have an in-line mixing feature at the tip, mixing the contents of all barrels as the syringe plunger is depressed. The syringe may be equipped with an external heating foil and thermistor to preheat the contents that will be activated and controlled when placed in the docking station. 
         [0068]    The docking station of the present invention addresses quality control and regulatory concerns of coating an implantable medical device at the point of care by delivering a reproducible process that is independent of user training or skill. The docking station capabilities including one or more of the following:
   provides a controlled process for coating an implantable medical device at the point of care, independent of skill level or training of the attending medical personnel;   reads barcodes, confirms drug, devices and process;   has the means to provide a level plane for even distribution of coating;   mixing: the docking station can include a mixer;   rotation: chamber rotation insures even coverage of the device;   temperature control within the chamber and of the syringe containing the polymer and/or therapeutic agent;   atmosphere control—gas, pressure and/or vacuum if required;   times and controls specific processes;   indicates stage of process and when cycles are complete;   coats a device by immersion (rotates chamber 180 degrees), bath with rotation (such as 350 degree reversing rotation) for uniformity, and/or atomizing spray heads;   delivers and controls energy to cure the polymer/therapeutic agent coating by light, microwave and/or heat.   
 
         [0080]    In addition, the coating chamber has capabilities which include one or more of the following:
   provides a sterile, robust container for shipping and inventory;   provides an environmentally controlled chamber for coating a sterile implantable medical device with a polymer and/or therapeutic agent at the point of care;   provides a means of distributing the coating uniformly over the surface of the device by immersion, bathing the device and/or spray;   provides a means of curing a polymer under controlled atmosphere (vacuum or pressure, gas) and energy (heat, light and/or microwave).   
 
         [0085]    While the invention has been described with reference to preferred embodiments it is to be understood that the invention is not limited to the particulars thereof. The present invention is intended to include modifications which would be apparent to those skilled in the art to which the subject matter pertains without deviating from the spirit and scope of the appended claims.