Coating method and coating device

ES 2 554 380 T3

DESCRIPTION

Coating procedure and coating device

TECHNICAL SECTOR

Generally, a stent or stent (endoprosthesis), which is a type of mechanical device, is a tube-shaped device and is used for medical purposes, such as maintaining a situation where a part of stenosis that occurs in a blood vessel or other tubular lumen within a living organism, reinforcing a lumen and the like.

For example, in the case of using a stent to maintain the extension part after percutaneous transluminal coronary angioplasty (PTCA), the rate of restenosis is low compared to that of PTCA alone, but there is a problem that the restenosis will be confirmed in a proportion of approximately 20% to 30%. A major cause of restenosis after stenting is intimal hyperplasia. Accordingly, a drug-releasing-type stent has been developed, which prevents restenosis by coating a stent with a drug that can suppress the migration and proliferation of vascular smooth muscle cells, which are the direct cause of intimal hyperplasia, and by releasing the drug into the stent placement site.

As a medicine, taxol (paclitaxel), mitomycin C, adriamycin, genistein, tyrphostin, cytochalasin, sirolimus (rapamycin) or the like are used.

When coating is done, a coating liquid is used in which this drug and a biocompatible polymer are dissolved in a solvent and applied to part or all of a stent, such that there will be a predetermined amount. of medication on the surface of the stent.

As a coating process that has been used in the past, a dipping process, a spraying process and the like are known. The dipping process is a process in which a stent is dipped into a coating liquid, removed, dried, and solidified so that it forms a coating layer on the stent.

However, the stent is formed with a slot or a through hole (hereinafter referred to as part of the space) between linear tie rods, in such a way that a laminar element (membrane between tie rods) or a bridge in a part of space. In the case of using a stent that extends, there is a risk that said laminar element or bridge exert an influence on the mechanical function of the stent, a part of the laminar element or the bridge can be destroyed or detached after application of the stent and if it flows into a peripheral vessel, there is also a risk of blood flow obstruction, so it is not preferred.

On the other hand, the spraying process is a process in which a coating liquid is sprayed onto the outer circular surface and / or the inner circular surface of a stent while rotating the stent and / or moving the spray nozzle. , and drying and solidification are applied so that a coating layer is formed. However, with respect to the sprayed coating liquid, the amount thereof on the side where the amount disappears becomes larger than the amount fixed on the stent, and a large amount of coating liquid will be wasted. In particular, many of the drugs included in the coating liquid are generally very expensive and if coating liquid is wasted, there is an immediate increase in the cost of the stent itself. Also, many of the drugs included in the coating liquid are drugs that have toxicity and it is also necessary to strictly carry out the safety management so that the drug is not dispersed to the environment by spraying, so that it will increase also the cost of its facilities.

Accordingly, a constitution has recently been used in which a web or a bridge will not be generated in the space portion, by the relative displacement of a spindle (mandrel) that supports the stent and said stent after applying a liquid of coating on a stent (see the characteristics and the like of Japanese Unexamined Patent Publication No. 2000-51367).

In addition, there is also a method in which a coating is used in the position of an electrode and an electrical charge is applied between a spraying means and the stent, in such a way that the efficiency of the coating is reinforced (see characteristics, figure 1 and the like from Japanese Unexamined Patent Publication No. 2003-205037).

In addition, there is also a method in which a stent shape configuration is obtained by scanning, and a coating liquid is applied following this configuration (see features, Figure 3 and the like of Unexamined Japanese PCT Publication No. 2005-514988).

ES 2 554 380 T3

However, with respect to the procedures disclosed in Japanese Unexamined Patent Publication No. 2000-51367 and Japanese Unexamined Patent Publication No. 2003-205037 mentioned above, neither of these has the procedure in which the Coating liquid is applied according to the shape of the stent configuration, and therefore coating liquid will undoubtedly be wasted.

Also, the Unexamined Japanese PCT Publication No. 2005-514988 procedure does not have such a defect, but refers to a procedure in which the coating liquid is applied using a solenoid, such that the amount of medicinal solution to be coated on the stent cannot be determined correctly and there is a problem that the effect of reducing the rate of restenosis is insufficient in the case of the above-mentioned PTCA or the like.

CHARACTERISTICS OF THE INVENTION

The present invention has been invented to solve the aforementioned problem and has the objective of providing a method of applying a coating material (-C-) to linear braces of a medical device having spaces formed between said linear braces, and of providing a coating layer having a uniform thickness that will be extremely precisely formed.

In particular, the invention relates to a method according to the preamble of claim 1, as known, for example, from WO 01/91918 A1.

This is achieved by a method of applying a coating material to linear braces of a medical device, according to independent claim 1. The dependent claims relate to advantageous embodiments.

When an application path is established to apply the aforementioned coating material over the entire surface of the aforementioned straps, the effect of the therapeutic substance occurs in all areas of the aforementioned straps.

With respect to the aforementioned tie rod, when an application path is established that includes at least some of the sections in which a repeated application is made and a section in which a jump is made from one point to another, the path The application rate can be shortened and rapid application is made possible. Furthermore, when setting an application mode, if the overlapping applied section is reduced or shortened as much as possible and if an application path is also selected to apply a coating material over the entire surface of the tie rods, a predetermined amount of drug can be applied quickly and evenly.

When the application path on the straight part of the tie is set to the center position in the width direction of the tie, the coating material is prevented from separating from the top of the tie and will never occur again. a laminar element or a bridge.

When the application path in the curved part of the strut is set at a position offset by a predetermined length in the width direction from the center position in the width direction of the strut, the coating material is prevented from separating from the upper part of the strut depending on the characteristics of the coating material discharged from the nozzle and it will never happen again that a laminar element or a bridge is generated.

In particular, if the position of deviation of the application path that is located in the curved part of the aforementioned strut is set from an orbit passing through the center of the curved part on the outside of the strut, separation is more reliably prevented. sheathing material relative to the tie rod.

If the setting of the application path is made to be at the intersection point of the central axis lines of the tie series or in the vicinity of the intersection point mentioned at the crossing portion of the tie, the sheathing material will separate from the top of the tie even if a series of sheathing layers are formed

With respect to the application paths, when said application paths of a coating layer in which the application has already finished and of the next coating layer are established in the same way on the tie rod, a series of layers of coating extremely comfortable and fast as well.

When the application path is set in such a way that it does not overlap with the application path of the coating layer in which the application has already finished, at least in a part of it, the coating material can be applied with a uniform thickness without separating from the top of the strap.

ES 2 554 380 T3

When a gap is arranged between the outer circular surface of a mandrel of a support that holds the aforementioned medical device and the inner circular surface of the strap of the aforementioned medical device, at least at the initial point of application, it is extremely comfortable. not only the application of the coating material but also the uncoupling of the medical device.

If the speed of travel of the application head is made faster during the section in which it passes a series of times, compared to the speed during the section in which it passes only once through a predetermined application path, the coating thickness is uniform and the application time can also be reduced.

If various kinds of coating materials are applied, the medicinal effects become compounded, the physical and mental burdens for the patient are reduced, and this is extremely advantageous.

If the distance between the mentioned nozzle and the mentioned tie is made from 1 pm to 100 pm or if the inside diameter of the leading edge of the mentioned nozzle is made from 5 pm to 250 pm, the application can be made without pour lining material off the tie rod.

When the application head includes a series of nozzles and a series of distributors, the application of the coating material can be done quickly.

When the coating apparatus includes a second position information obtaining means for measuring the position information of the displacement in the -Z- direction in the orthogonal coordinate system on the surface of the aforementioned strut, the application of the material becomes possible. coating corresponding to several tie rods.

If the mentioned control unit controls the movement of the mentioned application head and the mentioned nozzle along the established application path based on the position information that has been obtained by the first means of obtaining the information of the position that obtains the information of the position of the -X- direction and the -Y- direction in the mentioned orthogonal coordinate system and also, in such a way that the distance between the aforementioned application head and the aforementioned tie rod established based on the information of the position of the aforementioned displacement in the -Z- direction, whose second means of obtaining the information of the position obtained must be adjusted , or if the mentioned medical device, the mentioned application head and the like are housed in a chamber whose temperature and humidity are controlled, it is possible to extremely precisely form a coating layer having a uniform thickness.

Other objects, aspects and characteristics of the present invention will become apparent in view of preferred embodiments which will be exemplified in the explanation and in the accompanying drawings that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic front elevational view of a coating apparatus relating to the present invention;

Figure 2 is a schematic view, in front elevation, showing a support and an application head;

Figure 3A is an enlarged sectional view of a main part of Figure 2, and Figure 3B is a plan view showing a position of a stent corresponding to Figure 3A;

Figure 4 is the corresponding schematic view, in cross section, along a line 4-4 of Figure 1;

Figure 5 is a cross-sectional view showing an application situation of a series of coating layers;

Figure 6 is a plan view showing the path of application of a curved portion;

Figure 7 is a flow chart of a coating process; and Figure 8 is a flow chart of the coating process subsequent to Figure 7.

BEST WAY TO CARRY OUT THE INVENTION

Hereinafter, exemplified embodiments of the present invention will be explained in detail with reference to the drawings.

ES 2 554 380 T3

In the coating apparatus of this exemplified embodiment, shown in Figure 1, an airtight chamber -3- is formed therein by covering a frame -2- arranged in height on a base -1-, from the outer surface with a transparent synthetic resin plate (not shown). In the chamber -3-, a duct -4- is interconnected to an upper part thereof, and from an air conditioner -5- air is supplied whose temperature and humidity are controlled, the interior of the chamber being manufactured to be in a state at constant temperature and humidity, and the drying and solidification conditions are always kept constant when the coating material -C- mentioned later is applied on a stent -W-.

In the lower part of the interior of the chamber -3- there are arranged a support -10- to hold the stent -W- which is a medical device and displacement means -20- to displace the support -10-, and in a part intermediate, are mounted on a support frame -6- that laterally forms a bridge with the frame -2- an application head -30- that applies the coating material -C- on a tie -S- on the stent -W -; a first means -40- for obtaining information on the position that obtains information on the position of the directions -X-, -Y- in an orthogonal coordinate system on the surface of the stent -W-, in other words, on the tie rod surface -S-; and a second position information obtaining means -50- obtaining position information in the -Z- direction in the same orthogonal coordinate system.

On the other hand, on the outside of the chamber -3- a control unit -60- is arranged and is constituted in such a way that it controls the support -10-, the displacement means -20-, the application head - 30- and both means -40-, -50- for obtaining position information.

However, it is sufficient that there is at least the support -10- and the application head -30- inside the chamber -3-, and other means may not always be in a situation in which the temperature is controlled. and humidity.

This will be further described in detail. First, the support -10- is moved in the directions -X-, -Y by means of the displacement means -20-. As shown in Figure 2, the first displacement means -20x- in the -X- direction is a means of a so-called linear motor system, and a base plate -11- of the support -10- is mounted on a movable table -22- that moves along a displacement rail -21 that is a drive source. A part with a slide -12- is located on the base plate -11- of the support -10- and, in the part of the slide -12- there is arranged, for example, a second displacement means -20y- in the direction -Y- which is composed of a screw or similar transfer mechanism that is rotated by means of a motor -M1-. On the part of the slide -12- there are arranged a motor -M2- and a jaw part -13-, and the proximal end of a mandrel -14- on which the stent -W- is disposed in a detachable manner in the outer circle of the same that is held in the jaw part -13- and is constituted in such a way that it will be made to rotate in a forward and backward direction by means of the motor -M2-.

The outside diameter of the mandrel -14- is approximately equal to or somewhat greater than the inside diameter of the stent -W-, and the mandrel -14- is interchangeable according to the inside diameter of the stent -W- and there are prepared mandrels that have various kinds of outside diameters all of which are coated with a black coating material in such a way that it absorbs light and enhances the contrast ratio between the mounted strut -S of the stent -W- and the gap portions -O-.

Also on the mandrel -14- are formed, as shown in figure 3A, concave parts -15- on the surface of the outer circumference thereof. If the concave part -15- is formed on the surface of the outer circumference of the mandrel -14-, a gap -G- is created between the surface of the outer circumference of the mandrel -14- and the surface of the inner circumference -Sa - of the tie -S- of the stent -W- when said stent -W is mounted on the mandrel -14-. Due to this gap -G-, when the coating material -C is applied on the tie -S- and even if the coating material -C- comes out to the lateral surface of the tie -S-, the material can be prevented from coating -C- rotate around a part between the surface of the mandrel -14- and the inner surface of the stent -W- and it is possible, without generating a laminar element or a bridge, form a coating layer having a uniform thickness on the tie -S- of the stent -W-. Furthermore, it is also possible to avoid the difficulty of releasing in case of releasing the stent -W- from the mandrel -14-. The turning of the cladding material -Calrededor easily occurs at the initial point from which the cladding material -C- is applied on the tie -S-, in such a way that the formation of the concave part -15- is allowed to form. occurs only in a part corresponding to the initial point of application shown by -Ps- in Figure 3B, in other words, only in the lower part of the so-called X-shaped part ( crossing part of the tie -S-) that exists in an end zone of the tie -S-. However, it is not limited only to this, also allowing them to be easily formed in such a way that the concave parts -15- are created on the surface of the inner circumference of all the tie-rods -S- apart from both end parts, and it is allowed also form them partially.

In this case, the stent -W- is a stent that generally has a cylindrical shape throughout its shape, and is made up of bent or curved linear braces -S- that have a predetermined width and parts of space -O- which are formed between the struts -S-, and the stent is made of a biocompatible and biostable material. For example, as a metallic material, one can cite stainless steel, Ni-Ti alloy, tantalum, titanium, gold, platinum,

ES 2 554 380 T3

Inconel, iridium, tungsten, or cobalt alloy (which includes a cobalt-chromium-nickel alloy). As the high polymer material, there may be mentioned, for example, polytetrafluoroethylene, polyethylene, polypropylene, polyethylene terephthalate or polyamide. As the biodegradable high polymer material, there can be mentioned, for example, polylactic acid, polyglycolic acid, polylactide, polyglycolate, polyparadioxanone, trimethylene carbonate, ε-caprolactone and the like or a mixture, a copolymer of the above.

Also, the coating material -C- is a material that includes at least a solvent, a polymer and a therapeutic substance. It is preferred that a polymer usable as a coating material -C- is a material that has adequate adhesion to the tie -S- and has a film-forming ability that can follow the deformation of the stent -W-. It is sufficient that the polymer has any characteristics of biodegradable and non-biodegradable character, and it is preferred that the polymer has excellent biocompatibility characteristics to minimize inflammation of the wall of a blood vessel. Also, in case of non-biodegradable characteristics, it is preferable to select a controllable polymer, such that the therapeutic substance is removed over time and in case of biodegradability, it is preferable to select a polymer that decomposes in a suitable period of time. For example, as a biodegradable polymer, there can be mentioned polylactic acid, polyglycolic acid, polybutyric acid, polyhydroxybutyric acid, polyparadioxanone, trimethylene carbonate, ε-caprolactone, polymalic acid, poly-α-amino acid, collagen, laminin, heparan sulfate, fibronectin, vitronectin, crondoitin sulfate, hyaluronic acid, and the like or a mixture, or a copolymer of the foregoing.

As the non-biodegradable polymer, silicone, cellulose-based polymer, polyurethane, polyester, polymethacrylate, polyethylene oxide, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid or the like can be mentioned.

In the case of the therapeutic substance, as an example of a drug that suppresses the migration and proliferation of vascular smooth muscle cells, one can cite taxol (paclitaxel), actomycin C, mitomycin C, adriamycin, genistein, thyphostin, cytochalasin, sirolimus ( rapamycin), tacrolimus, everolimus or similar

It is preferred that the solvent is a solvent that dissolves a polymer, a therapeutic substance, and the like, but it is acceptable to select a solvent that can evenly disperse them. Likewise, it is preferred that the stent -W- is wettable and of a suitable evaporation rate, and the stent is selected reaching a balance between the two. As a preferred solvent, acetone, N-methylpyrrolidone, dimethylsulfoxide, toluene, xylene, methylene chloride, chloroform, Fleon, dioxane, acetic ether, tetrahydrofuran, dimethylformamide, dimethylacetamide or a mixture of the above can be mentioned.

Furthermore, it is also allowed to add additive agents aimed at adjusting the physical characteristics of the polymeric film, improving adhesion with respect to the stent -W-, adjusting the viscosity of the coating solution, preventing oxidation. of the therapeutic substance or the like. As such additives, there may be mentioned, for example, glycerol, triacetyl glycerin, ethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, propylene glycol, polyalkylene oxide, sebacic acid ester, citric acid ester, italic acid ester or the like.

The coating material -C- discharged from the nozzle -38- mentioned below is distributed over the strut -S-, in such a way that the viscosity of the coating material -C- is selected to be 0.1 cp at 10 cp and preferably 1.0 cp to 4.0 cp. When the viscosity is above this level, the case occurs where a high pressure is required for discharge, or the coating material cannot be discharged from the fine nozzle -38-, and when the viscosity is below below this level, the discharged coating material -C comes out of the tie -S- and the case may arise where a uniform coating layer cannot be formed.

The application head -30- includes, as shown in figure 4, a distributor -33- composed, for example, of a syringe operating mechanism and a nozzle part -34- to discharge the coating material -C -, which are mounted on a support -31- mounted on the support frame -6-, for example, by means of a vertical table -32- that moves in the -Z- direction by means of a screw displacement mechanism or similar driven by a motor -M3- and that gradually discharges the coating material -C- retained in the inside of it.

The distributor -33- of this exemplified embodiment includes, as shown in figure 2, a cylinder part -35- inside which the coating material -C- is retained, a piston part -36- arranged in such a way. slidable inside the cylinder part -35- and a drive unit -39- of an engine, a liquid pressure mechanism or the like, which pushes the piston part -36- with a predetermined force -F-.

The nozzle part -34- is composed of a mounting element -37- which is arranged at the lower end of the cylinder part -35- and of the nozzle -38- which is suspended from the mounting element -37-, and the flow path (not shown) is formed through which the coating material -C- flows from the cylinder part -35- to the nozzle -38-,

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The outside diameter of the nozzle tip -38- is from 10 pm to 1000 pm, and the inside diameter of the nozzle tip is selected to be from 1 pm to 500 pm and preferably from 5 pm to 250 pm, such that the coating material -C- having the aforementioned viscosity must be expelled with a predetermined discharge rate. In the case of 5 pm or less, the coating material -C- does not flow smoothly and also, a large pressure will be required for discharge, and in the case of 250 pm or more, there is a risk that the coating material -C- cannot be applied substantially smoothly over the top of the stent -W- currently being used.

Likewise, it is preferred that the nozzle -38- is polished in such a way that the irregularities of the surface thereof are the minimum possible to avoid adhesion of the discharged coating material -C-. Therefore, it is preferable to use, for example, stainless steel, carbon steel, nickel, chromium, glass, aluminum oxide, zirconium oxide, diamond, a mixture of the above or the like, which is a material that can be processed with precision easily.

In particular, the distributor -33- of this exemplified embodiment is constituted, as shown in Figure 2, in such a way that it must be located on the surface of the tie -S- being separated from it, in such a way that the distance -L- between the nozzle -38- and the tie -S- be a predetermined distance and the coating material -C- will be continuously ejected without interruption from the nozzle -38- directed to the surface of the tie -S-. If such a continuous ejection system is used, a uniform application of the coating material -C- is made possible on the entire surface of the stent -W- and also, the continuous ejection system can discharge quantitatively, so that the controllability is excellent. and a quantitative adjustment of the therapeutic substance can be carried out with reliable precision. Furthermore, inside the chamber which is set for a constant temperature and humidity, the state in which the coating material -C- dries and solidifies is constant, such that the production of the stent -W- on which the coating material -C- is deposited can be carried out simply and also quickly.

As for the distance -L- between the nozzle -38- and the tie -S-, this is selected to be from 0.1 pm to 200 pm and preferably from 1 pm to 100 pm. When the distance -L- is much greater than this distance, there is a problem that the coating material -C- is interrupted and when it is too small, there is a problem that the coating material -C- comes out of the surface of the tight.

It should be noted in this exemplified embodiment that the application head -30- is a head having a single nozzle piece -38- and a single distributor piece -33-, but it is also allowed to use a head having a series of nozzles. -38- and a series of distributors -33-. In the case where the head has a series of nozzles -38- and a series of distributors -33-, it is possible to carry out in this way the application of the coating material -C- in less time, improving productivity and this is also advantageous for the cost of production.

The first means -40- for obtaining position information is constituted, as shown in figure 1, by an image-forming means that is mounted in a fixed position on a support -41- that is mounted on the frame. support -6-. More specifically, the first position information obtaining means 40 is a means that includes a camera unit 42 and a line sensor unit (not shown) that is arranged such that it extends into the direction of the axis of the stent -W-, scans the surface of the stent -W- in synchronism with the rotation of the stent -W- of the support -10-, obtains an image of the surface of the stent -W- and communicates it to the unit control -60-. As the initial position in which the line sensor unit obtains the image of the surface of the stent -W-, any position is acceptable, but preferably it is established, for example, on a line of the axis corresponding to the initial point of application -Ps - previously mentioned. It should be noted that the camera unit -42- and the line sensor unit belong to matters in the public domain, so their details are omitted.

As mentioned above, the mandrel -14- is constituted in such a way that it is coated with a black coating material to absorb light and to reinforce the contrast ratio between the tie -S- of the mounted stent -W- and the space part -O- and the light will be absorbed, so that with respect to the image of the stent surface, the luminance of the strut -S- is high and the luminance of the space part -O- is low . Consequently, it is possible for the control unit -60- to distinguish the tie -S- and the space part -O- and output the coordinates of the tie -S-, that is, to output the information of the position of the directions - X-, -Y- of the tie -S performing a binarization of the image of the surface obtained from the stent -W- as a function of the appropriate luminance. Furthermore, the control unit -60- calculates the coordinates of an orbit that passes through the center of the tie -S- based on the position information obtained from the directions -XY- (-XY- coordinates of the tie -S- ), and the data obtained from the central orbit is stored in the memory of the control unit -60-. In the case of application of the lining material -C-, it is essential to prevent the lining material -C- from separating from the tie -S- and also for this reason, it is extremely important that the center of the tie -S- is specified .

The second means -50- for obtaining position information is constituted, as shown in figure 1, by a means for measuring the displacement of the direction -Z-, which is mounted in a fixed position at the lower end of the support -51- mounted on the support frame -6- and, more specifically, it is constituted by a

ES 2 554 380 T3 laser displacement sensor -52- called vertical sensor and which measures the displacement of the direction -Z of the tie-rod -S-.

The tie -S- is a tie whose surface is not smooth in a precise sense and has irregularities, and to apply the coating material -C- precisely quantitatively on the tie having said irregularities, the distal end of the nozzle -38- to be precisely parallel with the surface of the strut -S- and a predetermined amount of coating material -C- must be applied. Consequently, in this exemplified embodiment, using the displacement laser sensor -52-, the obtaining of the information of the position of the tie -S- is started from the predetermined position of the stent -W-, for example, from the initial point of application -Ps-, the displacement laser sensor -52- scans along the orbit that passes through the center of the tie -S- turning the stent -W- in the forward and reverse directions, and the displacement data in the -Z- direction of the entire -W- stent is collected and obtained. The displacement data obtained is communicated to the control unit 60 and stored in memory.

It should be noted in this exemplified embodiment that, as a second means -50- of obtaining the position information, a single piece of displacement laser sensor -52- is arranged, but when a series of laser sensors -52 are available - displacement, obtaining the position information can be performed more quickly.

The control unit -60- includes a processor, a monitor, a keyboard and the like, although not shown in the drawing, and based on the various kinds of position information mentioned, determines the setting of an application mode by the one where the coating material is applied, and an application path along which the application head -30- applies the coating material -C- on the tie -S- of the stent -W-. Likewise, the unit controls the rotation of the mandrel -14- on the support -10-, the displacement of the displacement means -20-, the amount to be discharged of the coating material -C- discharged from the application head -30-, scanning the imaging medium and vertical sensor, and the like.

In this case, an application mode means an application path in the case where the application runs along the tie -S- of the stent -W-. It is preferred that the application path is a path that does not have a section in which a repeated application is made and that can be applied continuously to the entire surface of the tie -S-, but there is the case of a stent -W - with braces -S- that intersect in a complicated way in which it is difficult to establish a trajectory that does not have any section in which the repeated application is made. In this case, a section can be arranged in which the repeated application is made or a section can be arranged in which a jump is made from a certain point of the tie -S- to another point thereof. Thus, the application path can be shortened by arranging a part with a repeated application section or with a skip section. Also, in a repeat application section (section of a series of passes), the drug can be applied uniformly over the entire surface of the stent -W- adjusting the speed to be faster than the travel speed during the section of a single pass, and it is possible to exert a sufficient effect of reducing the rate of restenosis in the case of PTCA or the like.

Also, at the time of determining the application path, it is preferable to implement various kinds of countermeasures described below.

(1) In case of applying the coating material -C- on the tie -S- of the stent -W-, it is preferable, in a straight part of the tie -S-, to establish that the orbit that passes through the center of the tie -S- be the application path. However, in a curved portion of the strut -S-, it is preferable to set the orbit passing through the position deflected by a predetermined length in the width direction of the strut -S- to be the application path. The coating material -C- is a liquid and is on the surface of the tie -S- in a situation where it is elevated due to surface tension, and even if it dries and solidifies, a coating layer will be formed with a arc-shaped cross section. In this case, when the application is run a number of times, it easily goes through a state where it is raised in an arc shape and this is not preferred. Accordingly, as shown in Fig. 5, it is preferred that the coating layer -E2- at the second time is formed as an orbit application path passing through a position offset by a predetermined length from the coating layer. lining -E1- of the first time of the tie -S-, and it is preferable that the coating layer -E3- for the third time uses as an application path thereof an orbit that passes through a different position from those of the application paths of the first and second times. It should be noted that it is preferred that this offset length takes into account the width -B1- of the tie -S- and the width -B2- of the coating layer -E-.

(2) When determining the application path, it is preferable that the application paths are different with respect to the linear strut portion and the curved strut portion. In the strut part in a linear fashion, it is basically enough to make if an orbit passes through the center of the strut width direction -S- it is the application path. However, in the curved strut portion, if an orbit passing through the center of the strut width direction -S- is made to be the application path, the coating material -C- discharged from the strut head application -30- is affected by its viscosity, the rate of fall from the nozzle or the like, and does not follow the orbit of movement of the application head

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-30-. Accordingly, in this exemplified embodiment, as shown in Fig. 6, a curved line -P- (dotted line) is established as the application path passing through the outside of a curved line (dotted line). that passes through the center of the curved part of the strap -S-.

In this case, the application path -P- of the dotted line protrudes towards an outside part of the tie -S-, and this is based on the knowledge that, when the coating material -C- applied on the tie -S - is continuously being pushed out, the cladding material -C- can be more reliably prevented from separating from the tie-rod -S- depending on the characteristics of the cladding material -C-.

(3) In the crossing part of the tie -S-, it is preferable that the point of intersection of a line of the central axis of said series of tie -S- or the vicinity of the intersection point of the same. In the part where the tie -S- intersects, the application path -P- will also cross, in such a way that if the intersection point of a line of the central axis of the ties is established as the application path -S- or the vicinity of the point of intersection thereof, it is possible to prevent the coating material -C- from coming out, and this is preferred.

Next, the coating procedure will be explained. Figure 7 and Figure 8 are flow charts showing a coating procedure.

<Preparation process>

In the first place, at the time of starting the coating, the air conditioner -5- is activated and the interior of the chamber -3- is made to be in constant temperature and humidity conditions. Next, on the support frame -6-, the syringe operating mechanism -33- formed by combining the nozzle part -34- including the nozzle -38- with an inner diameter corresponding to the width -B1- of the tie rod -S- and the lining material -C-, the cylinder part -35- retaining the lining material -C- and others.

On the other hand, the stent -W- is fixed on the mandrel -14- and then it is mounted in the jaw part -13- of the support -10- which is located in the waiting position. At that time, the application starting point -Ps- of the tie -S- must be established in a position on the concave part -15- of the mandrel -14-. At this time, if the displacement means -20- is in the lower part of the chamber -3-, as shown in figure 1, the waiting position is in the proximity of the inlet part -3A - from camera -3-.

<Imaging process>

The control unit 60 accepts an input of imaging parameters, and the inputted imaging parameters are stored in a storage device -S1-. Imaging parameters are entered, for example, from an operator-dependent keyboard. The imaging parameters include the rotational speed of the mandrel 14, the number of imaging lines, the width of the imaging line, and the operating speed during imaging.

The control unit 60 commands the start of imaging after storing the entered imaging parameters. Simultaneously, the displacement means -20x- is activated (-S2-) in the -X- direction. When the displacement means -20x- is activated in the -X- direction, the support -10- moves from the waiting position below the first means -40- for obtaining position information by means of the displacement rail - twenty-one-. The control unit -60- confirms that the support -10- has reached the predetermined position (-S3-) and if the support -10- has reached the predetermined position, it activates the motor -M2- of the support -10- and starts the rotation of the stent -W- (-S4-).

On the other hand, the line sensor of the first means -40- for obtaining position information starts the image formation by the instruction of the start of image formation, relatively scans the surface of the stent -W-, because the stent -W- rotates and images the surface configuration of stent -W- (-S5-). The image formed is stored in the storage device (eg memory, hard disk or the like) of the control unit 60 as a development image in a plan view. In addition, it is also allowed to use a constitution in which a visual confirmation is possible by broadcasting it to a monitor.

With respect to the image of the surface of the stent -S-, the luminance of the tie -S- is high and the luminance of the space part -O- is low, so that the control unit -60- transforms that in a binarized black and white image by setting a certain luminance as a limit (-S6-) and calculates the coordinates of the orbit that passes through the center of the tie -S- by a process of tuning the width of the tie - S (-S7-).

ES 2 554 380 T3 <Application mode setting process>

Taking into account the image of the surface of the stent -W- obtained through the aforementioned process and taking into account the need / not need and the position of the section in which the repeated application is made and the section in which it is made one jump, all tie rod surfaces -S- are applied, and the application path is set in such a way that the section in which the repeated application and the section in which the jump is made will be reduced or shortened as much as possible (-S8-).

<Displacement measurement process in -Z- direction>

Next, the control unit -60- accepts an input of the displacement measurement parameters from the second position information obtaining means -50-, which is the displacement measurement means in the -Z- direction, and stores it. (-S9-). These displacement measurement parameters are also entered by an operator. Displacement measurement parameters include data for measurement start position, measurement direction, branch point direction, measurement speed, and measurement point interval.

The control unit -60- activates the motor -M1- of the displacement medium -20y- in the -Y- direction after storing the displacement measurement parameters (-S10-). At that time, if necessary, while observing by a video camera and a monitor, the stent -W- and the measurement position of the displacement measurement means are adjusted such that the measurement position of said displacement measurement means displacement measurement and the specified position in the orbit become the same position (-S11-).

When the measurement position and the specified position become the same position by this setting (in this case, their match is entered by an operator in the control unit -60- ((-S12-): Yes) ), the control unit -60- instructs the second means -50- for obtaining position information to start the measurement of the displacement in the -Z- direction in the strut -S- (-S13-). Simultaneously, the control unit -60 performs direct and inverse rotations by means of the motor -M2- and the movement of the axis direction is repeated by the motor -M1-. In this way, the stent -W- repeats the rotation and displacement of the axis direction (-S14-).

Therefore, the second means -50- for obtaining position information moves along the orbit that passes through the center of the strut -S-, in such a way that the control unit -60- collects the data shift in the -Z- direction (-S15-). This displacement data is stored in the storage device of the control unit -60- together with the coordinates of the mentioned central orbit.

<Application process>

The control unit -60- accepts an application parameter input, and stores it (-S16-). The application parameters are also entered by an operator. Application parameters include data of application start position, application direction, direction at intersection, orbit adjustment section setting, orbit deviated length, velocity of application, the discharge speed of the coating material -C-, the height of the application head, the number of applications (number of layers) and the selection of application heads.

The control unit -60- commands the start of the application after storing the application parameters. Simultaneously, the control unit -60- commands the displacement of the support -10- by the displacement means -20x- in the direction -X- (-S17-). Therefore, the stent -W- moves to the application start position under the application head -30- (-S18-). If the stent -W- has reached the application start position under the application head -30- ((-S19-): Yes), the direct and reverse rotations are ordered by the motor -M2- and the displacement of the axis direction by the motor -M1-, and the stent -W- is displaced in the direction of the axis -X- and in the axis direction -Y- depending on the designated parameter, according to the forward and reverse rotations by means of the motor -M2- and according to the displacement of the axis direction by means of the motor -M1 (-S20-). Simultaneously, the application head -2- moves in the direction of the -Z- axis by means of the motor -M3 depending on the designated parameters (-S21-). At that time, the coating material -C- is continuously discharged from the application head -2-. Therefore, the application head -2- applies the coating material -C- by moving along the predetermined application path.

During application, the space between the distal end of the nozzle -38- and the stent -W- is in a position to be filled by the coating material -C-, such that the coating material -C- is discharged in a fixed amount, and the amount of therapeutic substance on the stent -W- is also set as a predetermined value reliably. Furthermore, laminar elements and bridges will never be generated between the struts -S- and the cladding layer -E- can be formed extremely precisely.

ES 2 554 380 T3

When the coating has finished, the support -10- is moved to the standby position by means of -20x of movement in the -X- direction, the mandrel -14- is removed from the support -10- and extracted out of the chamber. -3-, and the stent -W- is released from the mandrel -14-.

The present invention is not limited only to the exemplified embodiments mentioned above and various modifications of the technical idea of ​​the present invention are possible, with the assistance of a person skilled in the art. For example, the exemplified embodiments mentioned above refer to a case where one kind of coating material -C- is applied, but depending on the situation, various kinds of coating materials can also be used. In case of applying a series of coating materials -C-, a series of syringes, nozzles and operating mechanisms of the syringe are arranged and the coating is executed by changing them sequentially. The sequential change of these syringe operating mechanisms and the like is controlled by the control unit 60. In this case, a different coating material -C- means a case where the polymer is different or the polymer is the same but the amount of it is different; the therapeutic substance is different or the amount of the therapeutic substance is different; or the solvent is different. Thus, if various kinds of coating materials are used, the medicinal effects become compound and this is extremely advantageous in cases such as the case where physical and mental burdens for a patient are reduced, or the like.

Also, in this exemplified embodiment, the support -10- is displaced by the first and second displacement means -20x-, -20y-, and the application head -30- and the first and second means -40-, -50- application of position information are fixed, but a constitution can not always be used in which only the support -10- is always moved and the other parts must be fixed. These displacements are allowed to be relative and, therefore, it is sufficient that predetermined displacement means are properly installed.

Furthermore, also with regard to the directions of movement of the support -10-, of the application head -30 and of the first and second means -40-, -50- for obtaining position information, a constitution in the one in which the application head -30- and the support -10- move relatively in two directions orthogonal to each other on the horizontal surface, or in which the movement is carried out relatively in the vertical direction, and it is also possible to select the most suitable situation depending on the shape or the like, of the stent -W-.

<Inventive example 1>

In the case of the -W- stent, the following stent was used and the coating was executed.

Stent -W-: inner diameter 1.7 mm, thickness 150 pm, total length 30 mm.

Strap width -S- (minimum): 107 pm

Bending radius of the tie -S- (minimum): R = 0.1 mm.

The strut configuration -S- is a configuration obtained by connecting rings composed of wavy shapes with connections in a linear shape.

The material of the stent -W- is stainless steel.

Coating material viscosity -C-: 2.5 cp (20 ° C)

Coating material discharge rate -C-: 0.0067 pl / s

Orbit adjustment deviated length of the curved part:

pm in direction -Y- (circumferential direction of the stent) pm in direction -X- (direction of the long axis of the stent)

Application speed in orbit passing through the center: 2.4 mm / s

Application speed in orbit deviated from center: 3.3 mm / s

Application speed in repeated application sections: 4.8 mm / s

Inner diameter of nozzle tip 38:43 pm

Nozzle tip outer diameter 38: 200 pm

ES 2 554 380 T3

Distance (-L-) between stent -W- and nozzle 38: 40 pm

Number of applications (number of layers): 10 layers

Regarding the application mode, a section was arranged in which the repeated application was performed in a part of the application path, but there was no section in which a jump was performed.

The average thickness of the coating layer of the stent of the example of the invention 1 was 40 pm and the coating could be carried out without the web, without the bridge and without leaving the lateral surface of the stent.

<Inventive example 2>

Next, with respect to the stent -W-, the following stent was used and the coating was carried out.

Stent -W-: inner diameter 1.7 mm, thickness 150 pm, total length 30 mm.

Strap width -S- (minimum): 104 pm

Bending radius of the tie -S- (minimum): R = 0.07 mm.

The configuration of the tie -S- is obtained by connecting rings composed of wavy shapes with connections in a linear way.

The material of the stent -W- is stainless steel.

Coating material viscosity -C-: 2.5 cp (20 ° C)

Coating material discharge rate -C-: 0.0056 pl / s

Orbit adjustment deviated length of the curved part:

pm in direction -Y- (circumferential direction of the stent) pm in direction -X- (direction of the long axis of the stent)

Application speed in orbit passing through the center: 4.4 mm / s

Application speed in orbit deviated from center: 5.7 mm / s

Application speed in repeated application sections: 8.8 mm / s

Inner diameter of nozzle tip 38:43 pm

Nozzle tip outer diameter 38: 200 pm

Distance (-L-) between stent -W- and nozzle 38: 40 pm

Number of applications (number of layers): 10 layers

Regarding the application mode, a section was arranged in which the repeated application was performed in a part of the application path, but there was no section in which a jump was performed.

The average thickness of the coating layer of the stent of inventive example 2 was 40 µm and the coating could be carried out without the web, without the bridge and without leaving the side surface of the stent.

INDUSTRIAL APPLICABILITY

In the present invention, it is possible to drastically reduce the rate of restenosis of the dilation part after percutaneous transluminal coronary angioplasty (PTCA).

Furthermore, the present invention is based on Japanese Patent Application No. 2007-72803, filed March 20, 2007, and the contents disclosed therein are referenced and incorporated herein in their entirety.