Electrodeposition coating for medical devices
10973959 · 2021-04-13
Assignee
Inventors
Cpc classification
A61L29/16
HUMAN NECESSITIES
A61L2300/416
HUMAN NECESSITIES
C25D7/00
CHEMISTRY; METALLURGY
B05D1/04
PERFORMING OPERATIONS; TRANSPORTING
International classification
C25D13/00
CHEMISTRY; METALLURGY
B05D1/04
PERFORMING OPERATIONS; TRANSPORTING
C25D7/00
CHEMISTRY; METALLURGY
A61L29/16
HUMAN NECESSITIES
Abstract
The present disclosure relates generally to coating medical devices. In particular, the present disclosure provides materials and methods for coating a portion of a balloon catheter with a pharmaceutical agent using electrodeposition techniques. Although angioplasty and stenting can be effective methods for treating vascular occlusions, restenosis remains a pervasiveness problem. Therefore, coating portions of a balloon catheter with a pharmaceutical agent that inhibits restenosis can reduce the likelihood of restenosis.
Claims
1. A method for coating a catheter, the method comprising: providing a catheter, wherein the catheter comprises a shaft, a balloon on the shaft, and a scoring element over the balloon, the scoring element comprising an elastic material configured to facilitate deflation of the balloon, wherein the scoring element is electrically conductive; submerging a portion of the scoring element into a coating solution within an electrophoretic coating apparatus, wherein the coating solution comprises at least one polar pharmaceutical agent dissolved into an aprotic polar solvent, and wherein the electrophoretic coating apparatus comprises a charged electrode submerged within the coating solution; and applying a substantially constant current across the portion of the scoring element, the coating solution and the charged electrode to thereby deposit a layer of the at least one polar pharmaceutical agent dissolved into the aprotic polar solvent directly onto the scoring element without the use of a chemical tie layer.
2. The method of claim 1, wherein the at least one scoring element is part of a network of scoring elements comprising an elastic metal cage that expands and contracts with inflation and deflation, respectively, of the balloon.
3. The method of claim 1, wherein the at least one scoring element is comprised of stainless steel, tantalum, platinum, cobalt chrome alloys, elgiloy or nitinol alloys.
4. The method of claim 1, wherein the at least one polar pharmaceutical agent comprises one or more of paclitaxel, docetaxel, DHA-paclitaxel, PG-paclitaxel, docosahexaenoic acid (DHA), rapamycin, or derivatives or combinations thereof.
5. The method of claim 1, wherein the aprotic polar solvent comprises one or more of dichloromethane (DCM), tetrahydrofuran (THF), ethyl acetate, acetone, dimethylformamide (DMF), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), methyl ethyl ketone (MEK) and propylene carbonate, or combinations or derivatives thereof.
6. The method of claim 1, wherein applying the coating solution to the scoring element while applying the constant current to the scoring element includes applying the coating solution to the scoring element while simultaneously applying the constant current-to the scoring element.
7. The method of claim 1 wherein the at least one polar pharmaceutical agent is capable of inhibiting restenosis.
8. The method of claim 1 wherein the at least one polar pharmaceutical agent is capable of inhibiting cellular mitosis.
9. A method for coating a catheter for insertion into a body lumen of a patient, the method comprising: providing a catheter comprising a shaft, a balloon on the shaft, and a scoring element over the balloon, the scoring element comprising an electrically conductive and mechanically elastic material configured to expand and contract with inflation and deflation, respectively, of the balloon within the body lumen of the patient; submerging a portion of the scoring element into a coating solution within an electrophoretic coating apparatus that is electrically coupled to the scoring element, wherein the coating solution comprises docetaxel dissolved into a dichloromethane solvent, and wherein the electrophoretic coating apparatus comprises a charged electrode submerged within the coating solution; and applying a substantially constant current across the portion of the scoring element, the coating solution and the charged electrode to thereby deposit a layer of docetaxel from the coating solution directly onto the scoring element without the use of a chemical tie layer.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings are incorporated into and form a part of the specification to illustrate several examples of the present disclosure. These drawings, together with the description, explain the principles of the disclosure. The drawings simply illustrate preferred and alternative examples of how the disclosure can be made and used and are not to be construed as limiting the disclosure to only the illustrated and described examples. Further features and advantages will become apparent from the following, more detailed, description of the various aspects, embodiments, and configurations of the disclosure, as illustrated by the drawings referenced below.
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DETAILED DESCRIPTION
(8) The present disclosure relates generally to coating medical devices. In particular, the present disclosure provides materials and methods for coating a portion of a balloon catheter with a pharmaceutical agent using electrodeposition.
(9) Referring to the flow chart in
(10) The pharmaceutical agent can be chosen based on its functional characteristics, including, but not necessarily limited to, the ability to inhibit restenosis, mitosis or cellular proliferation. For example, the polar pharmaceutical agent can be paclitaxel, docetaxel, DHA-paclitaxel, PG-paclitaxe, docosahexaenoic acid (DHA), or any combinations or derivatives thereof capable of inhibiting mitosis or cellular proliferation. In some cases, the presence of the inhibitor prevents restenosis that may occur in the absence of the inhibitor. For example, the polar pharmaceutical agent can be rapamycin (e.g., sirolimus) or a derivative of rapamycin (e.g., everolimus), or any combinations or derivatives thereof.
(11) The polar pharmaceutical agent of the method at 100 can be mixed with a nonpolar solvent suitable to dissolve the polar pharmaceutical agent and produce a coating solution (110). A suitable nonpolar solvent includes any known or hereafter discovered nonpolar solvent. Nonpolar solvents generally include molecules having an equal sharing of electrons among the atoms of the molecules (e.g., symmetrically or evenly distributed electrons), such that there is no net charge on the molecules (i.e., the charges cancel each other out). Generally, nonpolar solvents have a dielectric constant of less than 15. Nonpolar solvents that can be used with the methods disclosed herein include, but are not limited to, one or more of benzene, carbon tetrachloride, chloroform, cyclohexane, cyclopentane, dichloromethane, diethyl ether, 1,4-dioxane, hexane, pentane, toluene, or combinations or derivatives thereof. Once one or more polar pharmaceutical agents is dissolved in one or more nonpolar solvents, the resulting coating solution or suspension can be added or introduced into a coating apparatus (120).
(12) The polar pharmaceutical agent of the method at 100 can be mixed with a polar solvent suitable to dissolve the polar pharmaceutical agent and produce a coating solution (110). A suitable polar solvent includes any known or hereafter discovered polar solvent. Polar solvents generally include molecules having an unequal sharing of electrons among the atoms of the molecules (e.g., asymmetrically or unevenly distributed electrons), such that there is a net charge on the molecules or a portion of the molecules. Generally, polar solvents have a dielectric constant of greater than 5. Polar solvents that can be used with the methods disclosed herein include, but are not limited to, one or more aprotic solvents, including dichloromethane (DCM), tetrahydrofuran (THF), ethyl acetate, acetone, dimethylformamide (DMF), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), methyl ethyl ketone (MEK) and propylene carbonate, and combinations or derivatives thereof. Polar solvents that can be used with the methods disclosed herein include, but are not limited to, one or more protic solvents, including formic acid, n-butanol, isopropanol (IPA), ethanol, methanol, acetic acid, nitromethane and water, and combinations or derivatives thereof. Once one or more polar pharmaceutical agents is dissolved in one or more polar solvents, the resulting coating solution or suspension can be added or introduced into a coating apparatus (120). In addition, many liquid chromatography and mass spectrometry applications (e.g., electrospray technologies) utilize polar solvents such as methanol and water to carry molecules (e.g., polar pharmaceutical agents) to a detector. In such cases, polar solvents may also function as carriers of polar pharmaceutical agents. The selection of a particular polar or nonpolar solvent selection may be dependent on the solubility characteristics of the polar pharmaceutical agent to be deposited, as one of ordinary skill in the art would readily appreciate and understand, based on the present disclosure.
(13) The coating apparatus of the present disclosure facilitates the coating of at least a portion of a medical device with one or more pharmaceutical agents. Several nonlimiting embodiments of the coating apparatus of the present disclosure are described further in
(14) In some cases, the one or more electrically conductive portions of a medical device can be submerged in the coating solution during the coating process. In other cases, the coating solution can be deposited on to the one or more electrically conductive portions of a medical device by spraying (e.g., electrospraying). The sending of an electric current through the one or more electrically conductive portions of the medical device and the coating apparatus, as shown at 140, can produce a charge in the one or more electrically conductive portions of the medical device. As shown at 150, coating the one or more electrically conductive portions of the medical device with the polar pharmaceutical agent of the coating solution can be achieved when the electrical charge produced on the one or more electrically conductive portions of the medical device is opposite that of the polar pharmaceutical agent. In this manner, the polar pharmaceutical agent will be attracted to one or more charged electrically conductive portions of the medical device, thus depositing the polar pharmaceutical agent onto the one or more electrically conductive portions of the medical device. As shown at 160, once the coating process is complete, the one or more electrically conductive portions of the medical device can be removed from the coating apparatus and assembled as part of the medical device (e.g., a balloon catheter).
(15) The method at 100 possesses several advantages over other methods for coating electrically conductive portions of medical devices, including but not limited to, obviating the need for a chemical tie layer. Chemical tie layers were developed to prevent a pharmaceutical agent from falling off the coated portion of a medical device prior to reaching the desired location (e.g., a vascular occlusion). However, the production and manufacturing of a chemical tie layer as part of the process of providing a coated medical device is complex and expensive. Additionally, the chemical tie layer is largely dependent on the surface material to which the tie layer is applied, making it difficult to make the coating process consistent and uniform across different types of medical devices.
(16) Referring to
(17) A balloon catheter 200 of the present disclosure comprises a shaft 205 coupled to an inflatable balloon 210 and an expansible shell or cage 215. The expansible shell 215 is located at the distal end of the catheter shaft 205 and configured to receive inflation medium from the inflation lumen in the shaft 205. In this way, the balloon 210 can alternate from a contracted or non-inflated configuration, as shown in
(18) In some cases, the expansible cage 215 can include hexagonal cells which extend over the middle of the expansible shell when inflated, as shown in
(19) As the balloon 210 is inflated during an angioplasty procedure and the plurality of scoring elements 220 engage the occlusive material in the vessel, the pharmaceutical agent may be deposited into the occlusive material and exert its biological effects (e.g., anti-mitotic or anti-proliferative) on the occlusion and surrounding tissue. In some cases, a balloon angioplasty procedure performed with scoring elements comprising a coating of one or more pharmaceutical agents reduces the occurrence of restenosis, as compared to a balloon angioplasty procedure performed with uncoated scoring elements.
(20) In some cases, the local delivery of one or more polar pharmaceutical agents is achieved using dual-isolation balloon techniques (e.g., the TAPAS system). In such cases, a portion of a vessel to be treated is isolated using a plurality of balloons, one or more balloon placed proximal to the area to be treated, and one or more balloon placed distal to the area to be treated. Once the area of the vessel to be treated is isolated, blood may be aspirated from the vessel, and one or more polar pharmaceutical agents are released into the isolated portion of the vessel. The pharmaceutical agent(s) may be left for a specific amount of time, or at least enough time to allow the pharmaceutical agent(s) to contact the occlusive material and exert the desired pharmacological effect on the surrounding occlusion and/or tissues (e.g., mitotic inhibition). The pharmaceutical agent(s) are evacuated from the vessel and replaced by blood, and the balloons used to isolate the treated portion of the vessel are deflated to restore blood flow. The use of technologies capable of releasing energy can also be used to augment the delivery of the pharmaceutical agent(s) into occlusive material and or the surrounding tissue, such as, for example, radio frequency energy, acoustic energy, and laser energy.
(21) According to the present disclosure, one or more polar pharmaceutical agents can be deposited onto an electrically conductive portion of a medical device using various electrodepositing methods. In some cases, a polar pharmaceutical agent can be deposited on an electrically conductive portion of a medical device using a coating apparatus comprising an electrochemical cell, of which there are two types: voltaic cells and electrolytic cells. In the voltaic cell apparatus 300 of
(22) For example, a voltaic cell can be constructed by inserting a copper strip into one portion of a coating apparatus that contains an aqueous 1 M solution of Cu.sup.2+ ions and a zinc strip into a different portion of a coating apparatus that contains an aqueous 1 M solution of Zn.sup.2+ ions. When the circuit is closed, the zinc electrode (the anode) is spontaneously oxidized to Zn.sup.2+ ions, while Cu.sup.2+ ions are simultaneously reduced to copper metal at the copper electrode (the cathode). As the reaction progresses, the Zn anode loses mass as it dissolves to give aqueous Zn.sup.2+ ions, while the Cu cathode gains mass as aqueous Cu.sup.2+ ions are reduced to copper metal that is deposited on the cathode.
(23) According to the present disclosure, when a coating solution 305 comprising one or more polar pharmaceutical agents 310 dissolved in a polar or nonpolar solvent is added to the coating apparatus 315 comprising, for example, a Cu cathode 320, attractive forces between the positively charged Cu cathode 320 and the polar pharmaceutical agent 310 (e.g., a polar pharmaceutical agent having a predominately negative charge) can facilitate the electrodeposition of the polar pharmaceutical agent 310 onto the Cu cathode 320. In some cases, the cathode 320 can be an electrically conductive portion of a medical device, such as one or more scoring elements. Thus, the coating apparatus 315 of the voltaic cell apparatus 300 can be used to coat a portion of a medical device with the pharmaceutical agent 310 without the need for a chemical tie layer.
(24) Depending on the pharmaceutical agent(s) to be deposited and the substrate on which the pharmaceutical agent(s) is to be deposited, it may be desirable to minimize the amount of undesired ions (e.g., solvent molecules) that may be deposited on the substrate during the deposition process. For example, to minimize the deposition of undesirable ions, one or more polar pharmaceutical agents may be dissolved in a nonpolar solvent instead of a polar solvent. However, if it is not undesirable to deposit more than just the polar pharmaceutical agents onto a substrate during the deposition process, then one or more pharmaceutical agents may be dissolved in either a polar solvent or a nonpolar solvent.
(25) With regard to a coating apparatus comprising an electrolytic cell apparatus 400, as shown in
(26) According to the present disclosure, when a coating solution 405 comprising one or more polar pharmaceutical agents 410 dissolved in a polar or nonpolar solvent is added to the coating apparatus 415 of the electrolytic cell apparatus 400, attractive forces between the negatively charged cathode 420 and the polar pharmaceutical agent 410 can facilitate the electrodeposition of the polar pharmaceutical agent 410 onto the cathode 420. Additionally or alternatively, when a coating solution 405 comprising one or more polar pharmaceutical agents 410 dissolved in a polar or nonpolar solvent is added to the coating apparatus 415 of the electrolytic cell apparatus 400, attractive forces between a positively charged anode and the polar pharmaceutical agent 410 can facilitate the electrodeposition of the polar pharmaceutical agent 410 onto the anode (not shown). In some cases, the anode or cathode of the electrolytic cell apparatus 400 can be an electrically conductive portion of a medical device, such as one or more scoring elements. Thus, the coating apparatus 415 of the electrolytic cell 400 can be used to coat a portion of a medical device with a pharmaceutical agent 410 without the need for a chemical tie layer.
(27) In other cases, the anode may be a solid pellet comprising one or more pharmaceutical agents, and an electrically conductive portion of a medical device may be the cathode (e.g., a scoring element). The coating solution may comprise a polar or nonpolar solvent in which the anode, the pellet comprising the pharmaceutical agent(s), is placed, in lieu of dissolving the pharmaceutical agent(s) directly in the polar or nonpolar solvent. Attractive forces between the negatively charged cathode and the positively charged anode/polar pharmaceutical agent(s) can, for example, facilitate the electrodeposition of the polar pharmaceutical agent onto the cathode.
(28) In some cases, a polar pharmaceutical agent can be deposited on an electrically conductive portion of a medical device using a coating apparatus comprising an electrophoretic apparatus 500, as shown in
(29) According to the present disclosure, when a coating solution 505 comprising one or more polar pharmaceutical agents 510 suspended in a polar or nonpolar solvent is added to the coating apparatus 515 of the electrophoretic apparatus 500, an electrical current generated between the negatively charged electrode and the positively charged electrode facilitates the electrodeposition of the polar pharmaceutical agent 510 onto the negative electrode 520 (or a separate negatively charged substrate). Additionally or alternatively, when a coating solution comprising one or more polar pharmaceutical agents 510 suspended in a polar or nonpolar solvent is added to the coating apparatus 515 of the electrophoretic apparatus 500, an electrical current generated between the positively charged electrode and the negatively charged electrode facilitates the electrodeposition of the polar pharmaceutical agent 510 onto the positive electrode (or a separate positively charged substrate). In some cases, the negative or positive electrode of the electrolytic cell apparatus 500 can be an electrically conductive portion of a medical device, such as one or more scoring elements. Thus, the coating apparatus 515 of the electrophoretic apparatus 500 can be used to coat a portion of a medical device with a polar pharmaceutical agent 510 without the need for a chemical tie layer.
(30) Depending on the pharmaceutical agent(s) to be deposited and the substrate on which the pharmaceutical agent(s) is to be deposited, it may be desirable to minimize the amount of undesired ions (e.g., solvent molecules) that may be deposited on the substrate during the deposition process. For example, to minimize the deposition of undesirable ions, one or more polar pharmaceutical agents may be dissolved in a nonpolar solvent instead of a polar solvent. However, if it is not undesirable to deposit more than just the polar pharmaceutical agents onto a substrate during the deposition process, then one or more pharmaceutical agents may be dissolved in either a polar solvent or a nonpolar solvent.
(31) In some cases, a polar pharmaceutical agent can be deposited on an electrically conductive portion of a medical device using a coating apparatus comprising an electrospraying apparatus 600, as shown in
(32) According to the present disclosure, when a coating solution 605 comprising one or more polar pharmaceutical agents 610 suspended in a polar or nonpolar solvent is added to a coating apparatus 615 of the electrospraying apparatus 600, attractive forces between, for example, the negatively charged substrate 620 and the polar pharmaceutical agent 610 facilitates the electrodeposition of the polar pharmaceutical agent 610 onto the substrate 620. In some cases, the negatively or positively charged substrate 620 of the electrospray apparatus 600 can be an electrically conductive portion of a medical device, such as one or more scoring elements. Thus, the coating apparatus 615 of the electrospray apparatus 600 can be used to coat a portion of a medical device with a polar pharmaceutical agent 610 without the need for a chemical tie layer.
(33) Depending on the pharmaceutical agent(s) to be deposited and the substrate on which the pharmaceutical agent(s) is to be deposited, it may be desirable to minimize the amount of undesired ions (e.g., solvent molecules) that may be deposited on the substrate during the deposition process. For example, to minimize the deposition of undesirable ions, one or more polar pharmaceutical agents may be dissolved in a nonpolar solvent instead of a polar solvent. However, if it is not undesirable to deposit more than just the polar pharmaceutical agents onto a substrate during the deposition process, then one or more pharmaceutical agents may be dissolved in either a polar solvent or a nonpolar solvent.
(34) The present disclosure, in various aspects, embodiments, and configurations, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various aspects, embodiments, configurations, sub combinations, and subsets thereof. Those of skill in the art will understand how to make and use the various aspects, aspects, embodiments, and configurations, after understanding the present disclosure. The present disclosure, in various aspects, embodiments, and configurations, includes providing devices and processes in the absence of items not depicted and/or described herein or in various aspects, embodiments, and configurations hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and\or reducing cost of implementation.
(35) The foregoing discussion of the disclosure has been presented for purposes of illustration and description. The foregoing is not intended to limit the disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the disclosure are grouped together in one or more, aspects, embodiments, and configurations for the purpose of streamlining the disclosure. The features of the aspects, embodiments, and configurations of the disclosure may be combined in alternate aspects, embodiments, and configurations other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed aspects, embodiments, and configurations. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the disclosure.
(36) Moreover, though the description of the disclosure has included description of one or more aspects, embodiments, or configurations and certain variations and modifications, other variations, combinations, and modifications are within the scope of the disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative aspects, embodiments, and configurations to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter.