Patent Application
20170367705
The present invention relates to drug coated balloons, and in particular to drug coated balloons having a microcrystalline structure and techniques for increasing vascular permeability for drug application and retention.
Vascular diseases, such as atherosclerosis, artery occlusion, and restenosis, are a leading cause of human mortality and morbidity. Vascular diseases arise from a variety of causes, and in some cases, necessitate surgical or endovascular intervention. Trauma to the vascular system can also necessitate surgical intervention to treat the traumatized anatomy. The treatment of vascular disease at a local, rather than systemic, level is often preferred. Systemic administration of drugs can produce unwanted side effects, when compared to the local administration of a drug to a target tissue to treat vascular disease. The utilization of a drug-coated endovascular medical device has become a standard technique in the treatment of vascular disease. In particular, a common treatment for vascular disease is the short-term or long-term contact of a tissue with an endovascular medical device, such as a balloon or a stent, respectively, that is coated with a drug that prevents or reduces vascular disease at the site of contact. The short-term contact of vascular medical devices including catheter-based balloons, are often undertaken to treat vascular diseases and vascular trauma, and the long-term contact, e.g., implantation, of endovascular medical devices including vascular grafts, stent-grafts, and stents. Upon contact of the endovascular medical device with a diseased vascular tissue, the drug elutes from the endovascular medical device into the surrounding tissue at the site of contact, thereby treating the vascular disease at a local, rather than systemic, level.
Drug coated balloons (DCBs) are one example of a drug-coated endovascular medical device. The literature discloses the use of DCBs for the treatment of vascular diseases, including coronary artery disease and peripheral artery disease (see e.g., U.S. Pat. No. 5,102,402 to Dror et al.). Dror et al. disclose placing a DCB in a blood vessel lumen to treat the vessel wall, inflating the balloon, and contacting the balloon surface with the luminal vessel wall to deliver a drug into the blood vessel wall. The dosing of the drug to the treatment site using DCBs can be highly variable and unpredictable immediately after implantation or deployment, and local drug levels in the vascular tissue can be highly variable and unpredictable over an extended time. It is therefore desirable to have improved drug coated balloons and techniques for treating vascular disease that are reliable and reproducible in drug dosing.
In order to improve upon conventional DCBs and techniques for treating vascular disease, DCBs may be constructed of one or more layers of material selected to provide certain properties to optimize performance of the DCB in some particular way, depending on the application. In the case of multi-layer or composite balloons, the multiple layers within the composite may be different materials to obtain a blend of physical and/or chemical properties to optimize performance. U.S. Patent Application Publication No. 2016/0106961 to Cully et al. discloses composite or layered DCBs. The described composite materials can comprise a porous layer adhered to a blow moldable polymer, such as a composite material that comprises an expanded fluoropolymer layer that is adhered to a blow moldable polymer through a stretch blow molding process. Additionally, U.S. Patent Application Publication No. 2014/0271775 to Cleek et al. discloses composite or layered DCBs comprising substrates having oriented drug crystals of high aspect ratio habit. The described composite materials can comprise a substrate comprising a porous microstructure and an amount of crystalline paclitaxel comprising hollow crystal habits associated with the substrate.
Although the multi-layer or composite balloons described in Cully et al. and Cleek et al. achieve some success in the reliability and reproducibility of drug dosing, many of the conventional multi-layer or composite balloons demonstrate lower than optimal drug application and retention. This phenomenon arises due to a number of factors including a non-uniform coating of the drug on the substrate, particulation or loss of the drug coating during deployment of the DCB, and/or a non-uniform or incomplete transfer of the drug coating to the surface of the vessel lumen, which ultimately results in lower than optimal drug application and retention. Accordingly, the need exists for improved drug coated balloons and techniques for increasing vascular permeability for drug application and retention.
It has been thought that local tissue retention determines biological responses, but little has been understood regarding factors that determine retention in balloon based delivery. The coating morphology (e.g., the drug coating on at least a portion of the surface of balloon) versus drug-tissue binding was investigated using various methods to visualize the coating morphology and arterial drug distribution and retention. Imaging of various balloon surfaces coated with the different drug formulations comprising similar paclitaxel doses (e.g., 3.5 μg/mm2) revealed different coating morphologies. Imaging of various balloon surface coated with the same drug formulations comprising similar paclitaxel doses (e.g., 3.5 μg/mm2) revealed similar coating morphologies. In particular, currently available commercial drug coated balloons were compared versus various drug coated balloon embodiments described herein, and it was found that the commercial drug coated balloons had a fractured, amorphous morphology and the various drug coated balloon embodiments described herein had a microcrystalline morphology. Imaging of treated surfaces revealed differential coating efficiencies that correlated with differential drug delivery and retention where the various drug coated balloon embodiments described herein provided better delivery and retention.
Additionally, balloons with either a porous microstructure or a nonporous microstructure were investigated for utilization as drug-coated endovascular medical devices. In particular, it has been thought that increased drug dose or number of drug-coated balloon (DCB) inflations increases delivery and tissue retention of drug; however, this has never been validated. Upon further examination, it was surprisingly discovered that utilization of DCBs to provide multiple treatments at a site resulted in tissue retention of the drug that was higher than would be expected by the dose exposure alone. The multiple treatments may be provided: (i) using multiple DCBs, each inflated one or more times, or (ii) using a single DCB that is inflated a plurality of times.
In various embodiments, a medical device is provided for that includes a balloon including an outer surface, and a drug coating layer on the outer surface of the balloon. The drug coating layer may include microcrystals in a haystack orientation having random and a substantial absence of uniformity in placement on the outer surface of the balloon. Optionally, the microcrystals have a random and a substantial absence of uniformity in angles from the outer surface of the balloon. The drug coating may include paclitaxel.
In some embodiments, the outer surface of the balloon includes a non-porous polymer. In other embodiments, the outer surface of the balloon includes a porous polymer.
In certain embodiments, the balloon includes a layer material, wherein the layered material comprises a polymer layer adhered to a fluoropolymer layer including a porous microstructure, wherein layers are in overlying relationship to each other and the fluoropolymer layer is an outermost layer. Optionally, the drug coating layer penetrates the outer surface of the balloon by an average penetration depth of from 2 to 10 μm.
In various embodiments, a medical balloon is provided for that includes a thermoplastic polymeric layer defining an interior chamber, a polymeric layer over at least a portion of the thermoplastic polymeric layer, and a coating layer on at least a portion of the polymeric layer. The coating layer may include a therapeutic agent, an excipient, and microcrystals in a haystack orientation having random and a substantial absence of uniformity in placement on an outer surface of the polymeric layer.
In some embodiments, the polymeric layer is porous. In other embodiments, the polymeric layer is non-porous.
In some embodiments, a majority of the microcrystals each have a major dimension length that is at least 10 times greater than a major dimension width of the microcrystal.
In some embodiments, the microcrystals have a random and a substantial absence of uniformity in angles from the outer surface of the polymeric layer, and a majority of the microcrystals project from the outer surface at an angle of 5° to 15°.
In certain embodiments, the therapeutic agent includes paclitaxel, docetaxel, protaxel, arsenic trioxide, thalidomide, atorvastatin, cerivastatin, fluvastatin, betamethasone diproprionate, dexamethasone 21-palmitate, sirolimus, everolimus, zotarolimus, biolimus or temsirolimus.
In some embodiments, the coating layer includes the therapeutic agent and the excipient in a predetermined weight ratio of between 3:1 and 20:1. Optionally, a majority of the microcrystals each have a major dimension length that is at least 13 or at least 15 times a major dimension width. In other embodiments, a majority of the microcrystals each have a major dimension length that is between 12 μm and 22 μm, and the majority of the microcrystals each have a major dimension width that is between 0.5 μm and 2 μm.
In some embodiments, when the medical balloon is inflated in a vessel lumen for one minute, at least a portion of the coating layer transfers to at least a portion of the vessel lumen such that one hour after the inflation at least 14% of the portion of the vessel lumen is covered by the coating layer.
In other embodiments, when the medical balloon is inflated in a vessel lumen for one minute, at least a portion of the coating layer transfers to at least a portion of the vessel lumen such that one hour after the inflation at least 12% of a portion of a surface of the vessel lumen is covered by the coating layer.
In some embodiments, when the medical balloon is inflated in a vessel lumen for one minute, at least a portion of the coating layer uniformly transfers to the vessel lumen along a length of the vessel lumen.
In various embodiments, a method is provided for preparing a tissue for drug application whereby tissue retention is improved. The method includes providing one or more medical devices including a balloon including an outer surface and a drug coating on the outer surface of the balloon, and sequentially treating a vascular treatment site n times with the one or more medical devices. The dose amount of a drug from the drug coating that is retained by the tissue at one hour after the sequential treating is greater than the n times a dose amount retained by the tissue at one hour after a single treatment.
In some embodiments, the dose amount retained in the tissue at the one hour after the sequential treatment is about six times the dose amount retained by the tissue at the one hour after the single treatment, where the dose amount retained by the tissue at the one hour after the single treatment is from 1% to 10% of a loaded dose of the drug coating.
Optionally, a half-life of the drug retained in the tissue after the sequential treatment is greater than 13 hours. In some embodiments, the balloon is configured to release from 65% to 85% of drug from the drug coating upon inflation.
In certain embodiments, a dose amount of the drug retained in the tissue at the one hour after the sequentially treating is greater than 750 μg/g. In other embodiments, a dose amount of the drug retained in the tissue at the one hour after the sequentially treating is greater than 1150 μg/g. In other embodiments, the dose amount of the drug retained in the tissue at the one hour after the sequentially treating is greater than 50 μg/g. In yet other embodiments, the dose amount of the drug retained in the tissue at the one day after the sequentially treating is greater than 1 μg/g.
In various embodiments, a method is provided for preparing a vessel for drug application whereby tissue retention is improved. The method includes providing a medical device comprising a balloon comprising an outer surface and a drug coating on the outer surface of the balloon, where the drug coating comprises microcrystals in a haystack orientation having random and a substantial absence of uniformity in placement on the outer surface of the balloon, and treating a vascular treatment site with the medical device.
In some embodiments, the drug coating includes paclitaxel, the treating includes inflating the balloon at the treatment site for 1 minute, and when the balloon is inflated at the treatment site for 1 minute, less than about 35% of the drug coating remains on the outer surface of the balloon.
In some embodiments, the balloon includes a porous material, and where the drug coating includes paclitaxel, the treating includes inflating the balloon at the treatment site for 1 minute, and when the balloon is inflated at the treatment site for 1 minute, between about 15% and about 30% of the drug coating remains on the outer surface of the balloon. In other embodiments, the balloon includes a non-porous material, and where the drug coating includes paclitaxel, the treating includes inflating the balloon at the treatment site for 1 minute, and when the balloon is inflated at the treatment site for 1 minute, less than about 10% of the drug coating remains on the outer surface of the balloon.
In certain embodiments, the drug coating includes paclitaxel at a dose of 3-4 μg/mm2. Optionally, a dose amount of a drug from the drug coating retained in the tissue at one hour after the treating is greater than 5% of a load dose amount on the balloon. In some embodiments, the balloon includes a porous material, and a dose amount of a drug from the drug coating retained in the tissue at 72 hours after the treating is greater than 2% of a load dose amount on the balloon.
In some embodiments, the balloon includes a porous material, and a dose amount of a drug from the drug coating layer retained in the tissue at one hour after the treating is greater than 50 μg/g. In other embodiments, the balloon includes a non-porous material, and an enface tissue coating at one hour after the treating is greater than 12%. In yet other embodiments, the balloon includes a porous material, and an enface tissue coating at one hour after the treating is greater than 15%.
In various embodiments, a medical device is provided for that includes an elongate catheter shaft having a proximal section, a distal section, and an inflation lumen, and a balloon on the distal section of the shaft and including a balloon wall defining a chamber and including a layered material. The layered material may include a polymer layer adhered to a fluoropolymer layer comprising a porous microstructure, and the polymer layer and the fluoropolymer layer may be in an overlying relationship to each other and the fluoropolymer layer may be an outermost layer. The medical device further includes a drug coating on the fluoropolymer layer.
The drug coating may have microcrystals in a haystack orientation having random and a substantial absence of uniformity in placement on the balloon.
In some embodiments, the drug coating comprises paclitaxel and an excipient. Optionally, the drug coating comprises paclitaxel and the excipient in a predetermined weight ratio of between 3:1 and 20:1.
In certain embodiments, a dose density of the drug coating is from 2.0 to 7.0 μg/mm2.
In some embodiments, the balloon is configured to release from 70% to 85% of a drug from the drug coating upon an inflation time of about 60 seconds.
In some embodiments, the microcrystals have a random and a substantial absence of uniformity in angles from the fluoropolymer layer, and a majority of the microcrystals project from the outer surface at an angle of 5° to 15°.
Optionally, the drug coating penetrates the fluoropolymer layer by an average penetration depth of from 2 to 10 μm.
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principles of the invention.
Persons skilled in the art will readily appreciate that various aspects of the present disclosure can be realized by any number of methods and apparatuses configured to perform the intended functions. That is, other methods and apparatuses can be incorporated herein to perform the intended functions. It should also be noted that the accompanying drawing figures referred to herein are not all drawn to scale, but may be exaggerated to illustrate various aspects of the present disclosure. The figures should not be construed as limiting. Finally, although the present disclosure may be described in connection with various principles and beliefs, the present disclosure should not be bound by theory.
The following terms as used herein mean:
The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise.
The terms “substantially,” “approximately” and “about” are defined as being largely but not necessarily wholly what is specified (and include wholly what is specified) as understood by one of ordinary skill in the art. In any disclosed embodiment, the term “substantially,” “approximately,” or “about” may be substituted with “within [a percentage] of” what is specified, where the percentage includes 0.1, 1, 5, and 10 percent. The term “majorly” or “majority” indicates at least half or 50%.
The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, any of the present devices, systems, and methods that “comprises,” “has,” “includes” or “contains” one or more elements possesses those one or more elements, but is not limited to possessing only those one or more elements. Likewise, an element of a device, system, or method that “comprises,” “has,” “includes” or “contains” one or more features possesses those one or more features, but is not limited to possessing only those one or more features.
Any of the present devices, systems, and methods can consist of or consist essentially of—rather than comprise/include/contain/have—any of the described elements and/or features and/or steps. Thus, in any of the claims, the term “consisting of” or “consisting essentially of” can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.
Furthermore, a structure that is capable of performing a function or that is configured in a certain way is capable or configured in at least that way, but may also be capable or configured in ways that are not listed.
As used herein, “nominal diameter” means the approximate diameter of the balloon at the nominal inflation pressure. Beyond this state, pressure increases (e.g., up to the rated burst pressure) result in less than a 20% increase in diameter, less than a 15% increase in diameter, or less than a 10% increase in diameter. Typically, the nominal diameter is the labeled diameter as indicated on the instructions for the end user, e.g., a clinician.
A “microcrystal haystack” or the phrase “microcrystals in a haystack orientation” is defined as a plurality of microcrystals, the majority of which are oriented at less than a 20 degree angle from a surface on which they are positioned. In addition, the majority of the plurality of microcrystals each have a major (overall) dimension length that is at least five (5) times greater than the major (overall) dimension width of the microcrystal.
In various embodiments, a balloon is provided for that comprises an outer surface and a drug coating layer on the outer surface of the balloon. Conventional approaches for the treatment of vascular disease include the utilization of a drug coated balloon (DCB). However, a problem associated with traditional DCBs is the difficulty in maintaining tissue retention of the drug and reducing drug loss in the biological fluid, e.g., blood, during DCB transport to a therapeutic location, particularly when factors are present that increase rates at which drugs associate with and/or dissociate from receptors (i.e., reversible binding and binding kinetics). For example, the reversible binding of drugs to receptors within tissue is a function of dose and residence time.
Taxanes 125 such as paclitaxel are microtubule-binding drugs that target specific sites within the lumen of polymerized microtubules 120. The taxanes 125 act by binding to GDP-bound β-tubulin molecules and stabilizing them by changing their conformation to a more stable GTP-bound β-tubulin structure. The taxanes cytotoxic effect is attributed to their ability to bind tubulin, stabilize the protofilaments leading to microtubule over-polymerization, and ultimately death by apoptosis. However, without being bound by theory, the reversible binding of taxanes 125 to the lumen of the polymerized microtubules 120 may hinder diffusion of the taxanes 125 along the microtubule axis, and thus affect tissue retention of the taxanes 125.
In order to overcome the aforementioned tissue retention and drug loss problems, various embodiments are directed to DCBs advantageously having a coating morphology that maintains the drug on a surface of the DCB during transport, inflation, and deflation of the DCB to a therapeutic location, e.g., an arterial wall, while also increasing tissue retention of the drug transferred from the DCB. For example, use of a removable cover on the DCB and/or a porous layer over a surface of the DCB are techniques that have been used to traditionally maintain the drug on a surface of the DCB during transport, inflation, and deflation of the DCB. However, such techniques alone or in combination have not been able to achieve optimal tissue retention of the drug while minimizing drug loss on a surface of the DCB during transport, inflation, and deflation of the DCB.
Nonetheless, it surprisingly has been discovered that the coating morphology of a DCB may be controlled independent of the drug dose to minimize drug loss during transport, inflation, and deflation while also maximizing tissue retention of the drug without the need of an additional cover/layer over the coating. As shown in
Additionally or alternatively, in order to overcome the aforementioned tissue retention problem, other embodiments are directed to techniques for increasing tissue retention of a drug transferred from a DCB. There are a number of techniques for increasing the tissue retention by modifying the dose of the drug on the balloon and/or preparing the vessel for absorption of the drug. For example, increasing the dose of the drug (e.g.,
Nonetheless, it surprisingly has now been discovered that utilization of DCBs having a fluoropolymer surface demonstrates that tissue retention from DCB benefits from repeat inflations, such as by inflating multiple balloons at the same treatment site, but not due to increased dose exposure, which has been hypothesized. For example, although one skilled in the art would expect, at most, a 3× retention for 3× inflation using three DCBs, the results of repeated inflations or treatments provided a synergistic increase in tissue retention with greater than 3× retention, as demonstrated in the below Example 1. This demonstrates that repeated dilation (e.g., with a dose density of 3.6 to 4.1 μg/mm2 on a DCB having a fluoropolymer surface with a porous microstructure) may prepare the blood vessel for enhanced absorption and/or overcome restrictions of single dose retention.
As further shown in
As further shown in
For the commercial Nylon DCB,
Without being bound by theory, it has been demonstrated that the microcrystalline surface coating morphology comprising microcrystals in a haystack orientation may determine distribution of the drug on the inner surface of the blood vessel and in some manner may maximize tissue retention of the drug. In addition, the microcrystalline surface coating morphology comprising microcrystals in a haystack orientation may minimize drug loss during transport and/or during inflation and deflation without the need of an additional cover/layer over the drug coating, as demonstrated in the below Example 2. Thus, it surprisingly has now been discovered that utilization of DCBs having microcrystalline surface coating morphology comprising microcrystals in a haystack orientation on a fluoropolymer surface minimized drug loss during transport, inflation, and deflation without the need of an additional cover/layer over the drug coating. Although one skilled in the art would expect that a DCB having an amorphous coating morphology, for example an amorphous, fractured appearance as shown in
Without being bound by theory, it has been demonstrated that the microcrystalline surface coating morphology comprising microcrystals in a haystack orientation may improve distribution of the drug on the inner surface of the blood vessel when positioned on either a porous or a non-porous polymer layer of a balloon.
Moreover, it surprisingly has now been discovered that utilization of drug-coated balloons with a fluoropolymer surface in our study demonstrated that tissue retention from DCB benefits from a microcrystalline surface coating morphology comprising microcrystals in a haystack orientation but not due to increased dose exposure, which has been hypothesized. Although one skilled in the art would expect that a DCB that delivers a higher initial dose exposure over that of another DCB will also have a higher retainable dose at 1 hour over that of the another DCB, the results of DCBs with a fluoropolymer surface and a microcrystalline surface coating morphology comprising microcrystals in a haystack orientation provided a synergistic increase in tissue retention, as shown in the below Example 2. This demonstrates that microcrystalline surface coating morphology on a drug-coated balloon with a fluoropolymer surface having a porous microstructure may prepare the artery for enhanced absorption and/or overcome restrictions of poor drug deliverance.
In various embodiments, a medical device is provided that comprises a balloon comprising an outer surface and a drug coating layer on the outer surface of the balloon. The drug coating may comprise microcrystals in a haystack orientation applied evenly across the outer surface of the balloon. The balloon can have any appropriate dimension and size for the clinical application. In some embodiments, the balloon is substantially cylindrical along the working length. In some embodiments, the balloon may be a wrapped balloon, for example a balloon helically wrapped at an angle between 20 degrees and 90 degrees or 40 degrees and 70 degrees, or other suitable wrap angles. In some embodiments, the balloon may be a wrapped balloon that is wrapped at approximately a 90 degree angle (i.e., a cigarette wrapped balloon). As shown in
With reference to
In some embodiments, the thermoplastic polymeric layer 740 defines the inner surface of the balloon wall 720, which serves as a bladder to retain the inflation fluid, and thus is composed of an impermeable or fluid-tight material. In accordance with such aspects, the polymeric layer 745 or other layer of material (e.g., a second polymeric layer) defines the outer surface 725 of the balloon wall 720. In alternative embodiments, the polymeric layer 745 defines the inner surface of the balloon wall 720, which serves as a bladder to retain the inflation fluid, and thus is composed of an impermeable or fluid-tight material. In accordance with such aspects, the thermoplastic polymeric layer 740 or other layer of material (e.g., a second polymeric layer) may define the outer surface 725 of the balloon wall 720.
In various embodiments, a coating layer 750 (e.g., a drug coating) is distributed evenly across at least a portion of the outer surface 725 of the layered material 735. For example, as shown in
As shown in
In some embodiments, a thickness of the coating layer 750 and the polymeric layer 745 is from 5 μm to 45 μm, for example, from 10 μm to 35 μm or about 25 am. In some embodiments, a thickness of the coating layer 750, the thermoplastic polymeric layer 740, and the polymeric layer 745 is from 30 μm to 60 μm, for example, from 40 μm to 55 μm or about 45 μm. A ratio of a thickness of the thermoplastic polymeric layer 740 to a thickness of the polymeric layer 745 may from 1.5:1 to 2.5:1, for example about 2:1 or about 30 μm of thermoplastic polymeric layer 740 to 15 μm of polymeric layer 745. A ratio of a thickness of the thermoplastic polymeric layer 740 to a thickness of (the polymeric layer 745 and the coating layer 750) may from 1:1 to 1.7:1, for example about 1.2:1 or about 30 μm of thermoplastic polymeric layer 740 to 25 μm of (the polymeric layer 745 and the coating layer 750).
The thermoplastic polymeric layer 740 may be comprised of a compliant, semi-compliant or non-compliant thermoplastic polymer. Suitable thermoplastic polymers include polymers that are medical grade and are blow moldable. Examples of suitable thermoplastic polymers can include polymethyl methacrylate (PMMA or Acrylic), polystyrene (PS), acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), modified polyethylene terephthalate glycol (PETG), cellulose acetate butyrate (CAB); semi-crystalline commodity plastics that include polyethylene (PE), high density polyethylene (HDPE), low density polyethylene (LDPE or LLDPE), polypropylene (PP), polymethylpentene (PMP); polycarbonate (PC), polyphenylene oxide (PPO), modified polyphenylene oxide (Mod PPO), polyphenylene ether (PPE), modified polyphenylene ether (Mod PPE), thermoplastic polyurethane (TPU); polyoxymethylene (POM or Acetal), polyethylene terephthalate (PET, Thermoplastic Polyester), polybutylene terephthalate (PBT, Thermoplastic Polyester), polyimide (PI, Imidized Plastic), polyamide-imide (PAI, Imidized Plastic), polybenzimidazole (PBI, Imidized Plastic); polysulfone (PSU), polyetherimide (PEI), polyether sulfone (PES), polyaryl sulfone (PAS); polyphenylene sulfide (PPS), polyether ether ketone (PEEK); fluoropolymers that include fluorinated ethylene propylene (FEP), ethylene chlorotrifluoroethylene (ECTFE), ethylene tetrafluoroethylene (ETFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy (PFA), or combinations, copolymers, or derivatives thereof. Other commonly known medical grade materials include elastomeric organosilicon polymers, and polyether block amide (e.g., PEBAX®). In particular, polyamides may include Nylon 12, Nylon 11, Nylon 9, Nylon 6/9, and Nylon 6/6. In certain embodiments, PET, Nylon, and PE may be selected for medical balloons used in coronary angioplasty or other high pressure applications. The specific choice of materials may depend on the desired characteristics/intended application of the balloon.
The polymeric layer 745 may be comprised of a compliant, semi-compliant or non-compliant polymer. Suitable polymers include a porous microstructure or a non-porous microstructure. In embodiments having a porous microstructure (referred to herein as a “porous layer”), suitable polymers include fluoropolymers, including without limitation perfluoroelastomers and the like, polytetrafluoroethylene and the like as well as expanded fluoropolymers. In embodiments having a non-porous microstructure (referred to herein as a “non-porous layer”), suitable polymers include polyamides including without limitation Nylon 12, Nylon 11, Nylon 9, Nylon 6/9, and Nylon 6/6.
The architecture of the porous microstructure may be selected based on the needs of the intended application. In some embodiments, the porous microstructure may be substantially fibrillated (e.g., a non-woven web having a microstructure of substantially only fibrils, some fused at crossover points or with smaller nodal dimensions). In other embodiments, the porous microstructure can comprise large nodes or large densified regions that may have an impact on the extent of compressibility/collapsibility of the material during blow molding. In still other embodiments, the porous microstructure can be a node and fibril microstructure somewhere between the aforementioned embodiments. In some embodiments, the porous microstructure can have an “open” microstructure such that the outer layer can have more loft and/or a drug coating layer can have more void space to occupy near the surface of the outer layer. Other examples of porous architectures can be fibrous structures (such as woven or braided fabrics), non-woven mats of fibers, microfibers, or nanofibers, flash spun films, electrospun films, and other porous films.
In some embodiments, the porous microstructure may be comprised of expanded fluoropolymers or expanded polyethylene (see e.g., U.S. Pat. No. 6,743,388 to Sridharan et al.). Non-limiting examples of expanded fluoropolymers include, but are not limited to, ePTFE, expanded modified PTFE, and expanded copolymers of PTFE. Patents have been filed on expandable blends of PTFE, expandable modified PTFE, and expanded copolymers of PTFE, such as, for example, U.S. Pat. No. 5,708,044 to Branca; U.S. Pat. No. 6,541,589 to Baillie; U.S. Pat. No. 7,531,611 to Sabol et al.; U.S. Pat. No. 8,637,144 to Ford; and U.S. Pat. No. 8,937,105, to Xu et at.
The polymeric layer 745 may be formed from a tubular member of a polymer having the porous or nonporous microstructure. The tubular member can be formed as an extruded tube or can be film-wrapped. The tubular member can have circumferential, helical, or axial orientations of the microstructure. In various embodiments, the tubular member can be formed by wrapping a film or tape and the orientation can be controlled by the angle of the wrapping. Tubular member can be circumferentially wrapped or helically wrapped. When a porous material is wrapped helically versus circumferentially or axially, the degree of compliancy in a given direction can be varied and can influence the overall compliancy of the composite. (As used herein, the term “axial” is interchangeable with the term “longitudinal.” As used herein, “circumferential” means an angle that is substantially perpendicular to the longitudinal axis.)
The coating layer 750 may be comprised of at least one natural, semi-synthetic or synthetic therapeutic agent (e.g., at least one drug). The functional characteristic of the coating layer 750 is to allow for release of at least one therapeutic agent to the tissue of a vascular wall during balloon inflation (e.g., treatment via percutaneous transluminal angioplasty in patients with obstructive disease of the peripheral arteries). In certain embodiments, the therapeutic agent is either lipophilic (partition coefficient between n-butanol and water >10) or displays very poor water solubility (<10 mg/ml, 20° C.). The wording “at least one therapeutic agent (or therapeutic agent preparation)” means that a single therapeutic agent or mixtures of different therapeutic agents are included. Thus, various therapeutic agents may be applied or combined, if different pharmacological actions are required or efficacy or tolerance is to be improved.
Therapeutic agents suitable for use in the coating layer 750 may include inhibitors of restenosis or cell proliferation (e.g., an anti-mitotic drug or anti-proliferative drug) such as vinco alkaloids, e.g., colchicine, podophyllotoxin, griseofulvin, anlimitotic alkaloid agents, and anti-microtubule alkaloid agents, and taxanes, e.g., paclitaxel, docetaxel, and protaxel. In certain embodiments, the therapeutic agent comprises paclitaxel or arsenic trioxide. Alternatively, therapeutic agents suitable for use in the coating layer 750 may include specific inhibitors of neovascularization such as thalidomide, statins like atorvastatin, cerivastatin, fluvastatin or anti-inflammatory drugs like corticoids or even lipophilic derivatives of corticoids such as betamethasone diproprionate or dexamethasone 21-palmitate, and Limus drugs, especially immuno-suppressants and mitosis inhibitors like mTOR inhibitors such as sirolimus, everolimus, zotarolimus, biolimus, temsirolimus. That is, for some embodiments the therapeutic agent comprises paclitaxel, a taxane, docetaxel, vinca alkaloids, colchicine, podophyllotoxin, griseofulvin, anti-mitotic alkaloid agents anti-microtubule alkaloid agents, protaxel, arsenic trioxide, thalidomide, atorvastatin, cerivastatin, fluvastatin, betamethasone diproprionate, dexamethasone 21-palmitate, sirolimus, everolimus, zotarolimus, biolimus or temsirolimus. As should be understood the at least one therapeutic agent may include structural analogs, related substances, degradants. and derivatives of any of the afore-mentioned drugs.
The coating layer 750 may be further comprised of an excipient including one or more saturated or unsaturated fatty acids. The excipient is a substance formulated alongside the therapeutic agent, and included for the purpose of long-term stabilization, bulking up solid formulations that contain potent active ingredients (thus often referred to as “bulking agents,” “fillers,” or “diluents”), or to confer a therapeutic enhancement on the therapeutic agent in the final dosage form, such as facilitating drug absorption, reducing viscosity, or enhancing solubility. Suitable excipients for use include one or more monocarboxylic acid salts (chain length C6-C30), preferably with Mg2+, Ca2+, Zn2+ or ammonium (NH4+), more preferably with Mg2+, Ca2+ or Zn2+. The C6-C30-monocarboxylic acid may be saturated or may have one or more double bonds (unsaturated). Examples of C6-C30-monocarboxylic acid salts are magnesium stearate, calcium stearate, zinc stearate, magnesium palmitate, calcium palmitate, zinc palmitate, magnesium myristate, calcium myristate, magnesium laurate, calcium laurate, magnesium caprinate, calcium caprinate, magnesium caprylate, calcium caprylate, magne-sium oleate, calcium oleate, magnesium palmitoleate or calcium palmitoleate. Optionally, the salts are admixed to at least one of stearic acid, palmitic acid, lauric acid, capric acid, caprylic acid, oleic acid, palmitoleic acid, stearic alcohol, palmitic alcohol, lauric alcohol, magnesium acetate and/or calcium acetate. That is, for some embodiments the C6-C30-monocarboxylic acid salt comprises a magnesium salt, calcium salt, zinc salt, or ammonium salt. In other embodiments, the C6-C30-monocarboxylic acid salt comprises magnesium stearate, calcium stearate, zinc stea-rate, magnesium palmitate, calcium palmitate, zinc palmitate, magnesium myristate, calcium myristate, magnesium laurate, calcium laurate, magnesium caprinate, calcium caprinate, magnesium caprylate, calcium caprylate, magne-sium oleate, calcium oleate, magnesium palmitoleate, calcium palmitoleate, tris stearate, lysine stearate, or arginine stearate. In yet other embodiments, the C6-C30-monocarboxylic acid salt comprises tris stearate, lysine stearate, or arginine stearate
In some embodiments, the C6-C30-monocarboxylic acid salt is a derivative of a C6-C30-monocarboxylic acid and a base. That is, for certain embodiments the C6-C30-monocarboxylic acid comprises stearic acid, palmitic acid, lauric acid, arachidic acid, capric acid, caprylic acid, myristic acid, behenic acid, lignoceric acid, cerotic acid, oleic acid, palmitoleic acid, Sapienic acid, elaidic acid, vaccenic acid, linoleic acid, linoelaidic acid, α-Linolenic acid, Arachidonic acid, Eicosapentaenoic acid, stearic alcohol, palmitic alcohol, caprylic alcohol, capric alcohol, lauric alcohol, myristic alcohol, arachidic alcohol, behenic alcohol, lignoceric alcohol, cerotic alcohol, magnesium acetate, or calcium acetate. The base may be an organic base such as a monovalent amine selected from the group consisting of ethanolamine, aminopropandiole, serinol, glucosamine, tris(hydroxymethyl)aminomethane, methylglu-camine, and an amino acid. In yet other embodiments, the salt may comprise C6-C30-monocarboxylic acid, tris stearate and reaction products of tris stearate with ethylene oxide.
The coating layer 750 may comprise the therapeutic agent and the excipient in a predetermined weight ratio calculated based on a formulation solution of the coating layer 750. In certain embodiments, the predetermined weight ratio (drug:excipient) is greater than 2:1, for example in terms of ranges between 3:1 and 20:1, and preferably greater than 3:1, for example in terms of ranges between 4:1 and 19:1, or about 19:1. A dose density of the therapeutic agent (e.g., 3.5 μg/mm2) is selected to provide a clinical dose of the therapeutic. The dose density of the therapeutic argent is the mass of the therapeutic agent within the portion of the outer surface 725 of the layered material 735. In some embodiments, the dose density of the therapeutic agent is from 2.0 to 7.0 μg/mm2, e.g., 3.3 to 3.8 μg/mm2 or from 3.6 to 4.1 μg/mm2. In other embodiments, the dose density is selected to provide a percentage (e.g., less than 100%) of the clinical dose of the therapeutic agent, for example a half (e.g., 1.8 to 2.05 μg/mm2), a third (e.g., 1.2 to 1.4 μg/mm2), a fourth (e.g., 0.9 to 1.03 μg/mm2) of the clinical dose. A dose density of the excipient is selected such that the predetermined weight ratio is maintained within the coating layer 750. The dose density of the excipient is the mass of the excipient within the portion of the outer surface 725 of the layered material 735. In some embodiments, the dose density of the total excipient mass is from 0.1 to 0.7 μg/mm2, e.g., 0.1 to 0.5 μg/mm2 or from 0.1 to 0.3 μg/mm2. In other embodiments, the dose density is expressed in terms of its individual constituents, where the dose density of the C6-C30-monocarboxylic acid is from 0.05 to 0.3 μg/mm2, e.g., 0.08 to 0.15 μg/mm2 and the dose density of the base is from 0.02 to 0.1 μg/mm2, e.g., 0.03 to 0.08 μg/mm2.
Typically, the therapeutic agent and mixtures of therapeutic agents with additives such as excipients are coated on medical devices (e.g., a balloon) as liquid formulations in volatile solvents. In various embodiments, the formulation for the coating layer 750 comprises at least one therapeutic agent, an excipient, and a solvent. The choice of the solvent may be useful for the crystal morphology of the coating layer 750 in a dry state and adherence and release of the therapeutic agent from the surface of the medical device. Accordingly, the solvent may include acetone, dioxane, tetrahydrofuran (THF), water, and mixtures thereof.
The choice of solvent must also consider toxicity and biocompatibility. The choice of the solvent, in accordance with various aspects discussed herein, was modified from conventional solvents formulations to remove a polar solvent, such as tetrahydrofuran (THF), in favor of components to enhance drug release of the therapeutic agent from the surface of the medical device, e.g., acetone and water. The polar solvent was initially included in the conventional solvent formulations to prevent precipitation of the therapeutic agent (e.g., about 25 mg/ml) in the coating solution but it did not enhance drug release. It has been found that dioxane may be substituted for the polar solvent because of its lower toxicity and higher boiling point; however, it was also found that the water content of the solvent formulation should be increased, resulting in a solvent system of acetone, dioxane, and water (e.g., 58:14:28% by volume respectively). Accordingly, the solvent may include acetone, dioxane, water, and mixtures thereof and optionally include acetone, water, and mixtures thereof.
The solvent dioxane provides acceptable drug release and transfer; however, while dioxane is less toxic than some conventional solvents, safety concerns still persist when handling and storing this solvent. The solvent formulation was further modified to remove dioxane; however, it was found that the therapeutic agent concentration should be lowered (e.g., about 17.5 mg/ml) resulting in a solvent system of acetone and water (e.g., 75:25% by volume respectively). Accordingly, in some embodiments, the solvent comprises acetone, dioxane, and water. In other embodiments, the solvent consists essentially of acetone, dioxane, and water. In alternative embodiments, the solvent comprises acetone and water. In yet other embodiments, the solvent consists essentially of acetone and water. In some embodiments, the solvent comprises from 35% to 85% by vol. of acetone, for example, about 75% or 0.75 v/v, and from 5% to 35% by vol. of water, for example, about 25% or 0.25 v/v. In other embodiments, the solvent comprises from 35% to 65% by vol. of acetone, for example, about 58% or 0.58 v/v, from 5% to 35% by vol. of water, for example, about 28% or 0.27 v/v, and from 5% to 30% by vol. of dioxane, for example, about 14% or 0.14 v/v.
In various embodiments, the formulation for the coating layer 750 comprises from 10 mg/ml to 30 mg/ml of at least one therapeutic agent, for example about 17.5 mg/ml; from 0.5 mg/ml to 3.5 mg/ml of excipient (in certain embodiments, from 0.2 mg/ml to 1.5 mg/ml of a C6-C30-monocarboxylic acid, for example, 0.62 mg/ml, and from 0.05 mg/ml to 0.7 mg/ml of a base, for example, 0.26 mg/ml); from 35% to 85% by vol. of acetone, for example, about 75% or 0.75 v/v; and from 5% to 35% by vol. of water, for example, about 25% or 0.25 v/v. In other embodiments, the formulation for the coating layer 750 comprises from 15 mg/ml to 35 mg/ml of at least one therapeutic agent, for example, about 25.0 mg/ml; from 0.5 mg/ml to 4.0 mg/ml of excipient (in certain embodiments, from 0.2 mg/ml to 1.8 mg/ml of a C6-C30-monocarboxylic acid, for example, about 0.88 mg/ml, and from 0.05 mg/ml to 0.9 mg/ml of a base, for example, about 0.37 mg/ml); from 35% to 65% by vol. of acetone, for example, about 58% or 0.58 v/v; from 5% to 35% by vol. of water, for example, about 28% or 0.27 v/v; and from 5% to 30% by vol. of dioxane, for example, about 14% or 0.14 v/v. However, one skilled in the art will understand that modifications of this formulation may be acceptable provided that the modifications do not change the primary constituents and may include, without limitation, modifications that involve similar derivatives and analogs to these primary constituents and/or involve additives to the formulation and/or its primary constituents.
As discussed herein, various embodiments are directed to DCBs advantageously having a coating morphology that maintains the drug on a surface of the DCB during transport, inflation, and deflation of the DCB to a therapeutic location, e.g., an arterial wall, while also increasing tissue retention of the drug transferred from the DCB. As shown in
A majority of the microcrystals 815 may extend from a surface of the substrate at an angle of less than 20° (thus the crystals lay relatively flat on the substrate). In other embodiments, a majority of the microcrystals 815 extend from the surface of the substrate at an angle of 00 to 17°, 50 to 15°, less than 15°, less than 10°, or less than 8°. Additionally, a majority of the microcrystals 815 each have a major dimension length that is at least ten (5) times greater than the major dimension width of the microcrystal. In other embodiments, a majority of the microcrystals 815 each have a major dimension length that is at least ten (10) times greater than the major dimension width of the microcrystal. In other embodiments, a majority of the microcrystals 815 each have a major dimension length that is at least 13 or at least 15 times a major dimension width. Additionally, a majority of the microcrystals 815 optionally each have a major dimension length that is between 12 μm and 22 μm, for example between 14 μm and 20 μm or about 17 μm, and a majority of the microcrystals 815 each have a major dimension width that is between 0.5 μm and 2.0 μm, for example between 0.8 μm and 1.6 μm or about 1.3 μm.
As shown in
Advantageously, the coating formulation and morphology allows for the therapeutic agent to adhere firmly enough to the substrate (porous and non-porous) to tolerate mechanical stress during production including folding of balloons, packaging, shipping to customers, and during final clinical use, which involves passage through a narrow hemostatic valve, an introductory sheath or guiding catheter, and a variable distance of possibly tortuous and narrow blood vessels. Moreover, the coating morphology is economical and efficient in manufacture as it does not require added costs or manufacturing steps to provide: a roughened balloon surface to enhance adherence, protective sheaths or membranes, or other physical or chemical methods to enhance adherence of the therapeutic agent to the balloon surface.
As shown in
In accordance with various embodiments, a DCB (e.g., as a part of a balloon catheter assembly) may be utilized to provide one or more treatments at a desired site in a body lumen. The DCB may include a balloon having a coating layer on an outer surface of the balloon, as described with respect to
As should be understood, the multiple or repeat treatments may be performed by inflating a single DCB multiple times at the same treatment site (as described in the above process), or by inflating multiple DCBs at a same treatment site multiple times (repeatedly performing the above process a number of times). For example, other aspects of the disclosure are directed to techniques of using the described DCBs in a sequential medical procedure. Such techniques can comprise passing the balloon catheter device with a DCB mounted thereon through an anatomical conduit or vessel to the desired position and inflating the described DCB to a nominal diameter once or sequentially. The method can further comprise expanding the balloon and delivering, upon inflation, a therapeutic agent that is on the outer surface of the balloon to a surrounding tissue or endovascular device. The method can further comprise sequentially retracting the balloon catheter device from the anatomical conduit or vessel and passing another DCB mounted to the balloon catheter device through the anatomical conduit or vessel to the desired position and inflating the subsequent balloon to a nominal diameter once or sequentially.
In accordance with various embodiments, the dose densities used for a single treatment utilizing a balloon comprising a fluoropolymer surface may provide for the release of from 68% to 83% of a loaded dose of the drug, e.g. between 72% and 77% of the loaded dose of the drug from the drug coating upon an inflation time of about 60 seconds. A loaded dose as used herein refers to the total mass of the drug on the balloon. In accordance with various embodiments, the dose densities used for a single treatment utilizing a 6 mm×40 mm balloon comprising a fluoropolymer surface may provide for the release of from 2200.0 μg to 2700.0 μg, e.g., 2350.0 to 2500.0 μg of the drug from the drug coating upon an inflation time of about 60 seconds. The tissue delivery of the released drug at one hour after a single treatment exhibited from about 10.0% to 30.0% enface tissue coating, e.g., from about 14.0% to 21.0% enface tissue coating, and at one day after a single treatment exhibited from about 0.1% to 10.0% enface tissue coating, e.g., from about 0.7% to 4.0% enface tissue coating. The released drug and resulting enface tissue coating may provide an initial delivered dose of drug to the tissue of from 29% to 73% of a loaded dose of the drug, e.g., 44% to 67%. The loaded dose of the drug corresponds to the total amount of the drug on the balloon and may be determined based on the dose density of the drug and the size of the balloon. In some embodiments utilizing a 5 mm×40 mm balloon, the initial delivery dose of drug to the tissue may be from about 750 to 1900 μg, e.g., 1150 μg to 1750 μg. Nonetheless, the dose amount retained by the tissue at one hour after the single treatment was surprisingly multiple times (e.g., greater than two times or greater than three times) the dose amount retained in the tissue at one hour after a single treatment of a traditional balloon. In some embodiments, the dose amount retained by the tissue at one hour after the single treatments is greater than two times, at least three times, at least four times, or at least five times the dose amount retained in the tissue at one hour after a single treatment of a traditional balloon. The dose amount retained in the tissue at one hour after a single treatment with a 5×40 mm balloon, for example, may be from 50 μg/g to 2000 μg/g. The dose amount retained in the tissue at one day after a single treatment with a 5 mm×40 mm balloon, for example, may be from 1 μg/g to 1000 μg/g. In some embodiments, the dose amount retained in the tissue at one hour after a single treatment with a 6 mm×40 mm balloon, for example, may be from 50.0 μg/g to 2000.0 μg/g. The dose amount retained in the tissue at one day after a single treatment with a 6 mm×40 mm balloon, for example, may be from 1 μg/g to 1000 μg/g.
In accordance with other embodiments, repeated treatments may be performed. In some embodiments, the dose densities used for each treatment may be the same or different dose densities from each other. Nonetheless, the dose amount retained by the tissue at one hour after the repeated treatments utilizing a balloon comprising a fluoropolymer surface was surprisingly multiple times (e.g., greater than three times) the dose amount retained in the tissue at one hour after a single treatment. In some embodiments, the dose amount retained by the tissue at one hour after the repeat treatments is greater than three times, at least four times, at least five times, at least six times, or at least seven times the dose amount retained in the tissue at one hour after a single treatment. The dose amount retained in the tissue at one hour after a single treatment with a 5×40 mm balloon may be from about 1% to about 10%, for example from 1% to 3% of the loaded dose of the drug on the balloon. In some embodiments, the dose amount retained in the tissue one hour after a single treatment with a 5×40 mm balloon may be from 60 to 90 μg/g, for example from 69.5 to 74.7 μg/g or from 71.5 to 72.7 μg/g. Surprisingly, however, the dose amount retained in the tissue at one hour after sequentially treating a vascular treatment site n times (e.g., three times) with the one or more medical devices (optionally using a same dose density for each treatment) may be greater than n times (e.g., three times) the dose amount retained in the tissue at one hour after a single treatment, for example, from 240 to 360 μg/g (four times), 300 to 450 μg/g (five times), 360 to 540 μg/g (six times), or 420 to 630 μg/g (seven times); from 278 to 298.8 μg/g (four times), 347.5 to 373.5 μg/g (five times), 417.0 to 448.2 μg/g (six times), or 486.5 to 522.9 μg/g (seven times); or from 286.0 to 290.8 μg/g (four times), 357.5 to 363.5 μg/g (five times), 429.0 to 436.2 μg/g (six times), or 500.5 to 508.9 μg/g (seven times).
Advantageously, the dose amount retained by the tissue after the repeated treatments was also surprisingly cleared at a slower rate. In some embodiments, a half-life of the drug retained by the tissue after the repeated treatments was greater than the half-life of the drug retained by the tissue after a single treatment. The half-life of the drug retained in the tissue after a single treatment may be from 6 to 8 hours. Surprisingly, however, the half-life of the drug retained in the tissue after repeated treatments (a plurality of treatments) (optionally using a same dose density for each treatment) may be greater than 8 hours, greater than 9 hours, greater than 10 hours, greater than 11 hours, greater than 12 hours, greater than 13 hours, greater than 14 hours, or greater than 15 hours. In terms of ranges, the half-life of the drug retained in the tissue after repeated treatments (optionally using a same dose density for each treatment) may be from 8 to 15, e.g., 10 to 14 hours.
It should be understood that although certain methods and equipment are described below, any method or equipment determined suitable by one of ordinary skill in the art may be alternatively utilized.
Membrane samples were die cut to form rectangular sections about 2.54 cm by about 15.24 cm to measure the weight (using a Mettler-Toledo analytical balance model AG204) and thickness (using a snap gauge-Mutitoyo Model, 547-400, 0.5″ diameter foot). Using these data points, mass per unit area was calculated with the following formula: m/(w*l), in which: mass per unit area (g/cm2), m=mass (g), w=width (cm), and l=length (cm). The average of three measurements was reported.
The bubble point test is used for pore size determination. It is based on the fact that, for a given fluid and pore size with a constant wetting, the pressure required to force an air bubble through the pore is inverse proportion to the size of the hole. The given fluid used for the examples disclosed herein was isopropyl alcohol, and the isopropyl alcohol bubble point was measured in the following manner: The material was restrained with a circular fixture of 1 inch diameter. The material was subjected to pressurized air at a pressurization rate of about 0.2 psi/sec. The pressure was increased until a stream of bubbles appeared, followed by additional streams of bubbles at similar pressures. The reported values represent the average measurements for five samples.
Without intending to limit the scope of the embodiments discussed herein, the systems and methods implemented in various embodiments may be better understood by referring to the following examples.
The preclinical performance of an embodiment of a DCB was evaluated where paclitaxel (PTX) was applied to an ePTFE porous surface of the balloon.
Methods: PTX coated balloons (W.L. Gore, Flagstaff Ariz.) with dose densities of 4.1 μg/mm2 (5×40 mm) or 3.6 μg/mm2 (6×40 mm) were inflated for 60 seconds in peripheral arteries of 30 Yorkshire swine (target balloon-to-artery ratio between 1.05:1-1.2:1). Arteries received a clinical dose via a single treatment or a safety margin dose via 3 sequential treatments with separate DCBs at the same angiographic site. Animals were euthanized from 1 h to 30 days (n=4-8/time point) post-treatment and subjected to comprehensive necropsies. Treated arteries, along with other tissues, were collected for bioanalysis or processed for histologic and scanning electron microscopy (SEM) evaluation. The time series of total arterial drug for each treatment group was fit to a bi-exponential model with zero plateau (R2≧0.999) and fits compared using a paired t-test.
Results: DCB treatments were successful in peripheral vessels, with absence of adherent thrombus on removed catheters and survival of all animals to scheduled time points. Devices released 74.6%±4.6% of PTX load during treatment. As shown in
While about 75% of the PTX load was released from the balloons independent of the number of inflations per artery, the amount inserted in the wall and retained over time differed. Arteries in the clinical single dose group absorbed only 72.1±0.6 μg PTX, of which 97% was cleared with a half-life of 8 hours. Although one skilled in the art would expect, at most, a 3× retention for 3× inflation using three DCBs, or 216.3 μg PTX, the results of repeated treatments provided a synergistic increase in tissue retention. Surprisingly, three exposures produced 6.6-fold more PTX, twice the difference from dose alone (478±8.1 μg, p<0.0001) and what was deposited was cleared 1.6 times slower; 92% with a half-life of 13 hours versus 8 hours (p=0.0028).
Conclusions: Overall, treatment in peripheral arteries with DCB embodiments of this disclosure at 1× clinical dose or 3× safety margin dose, resulted in acceptable acute device performance, no adverse safety events, and pharmacokinetics similar to other PTX coated balloons. Tissue retention from embodiments of this disclosure benefits from repeat inflations but not due to increased dose exposure. Repeated dilation may prepare the artery for enhanced absorption and/or overcome restrictions of single dose retention.
The preclinical performance of an embodiment of a DCB was evaluated, where paclitaxel (PTX) was applied to an ePTFE porous surface of the balloon.
Methods: PTX coated balloons (5 mm×40 mm and 6 mm×40 mm ePTFE—W.L. Gore, Flagstaff Ariz.) with dose densities of 3.5 μg/mm2 (labeled amount) or 3.3 μg/mm2 (measured amount) of paclitaxel were inflated in peripheral arteries of Yorkshire swine. PTX coated balloons (Commercial) with dose densities of 3.5 μg/mm2 (labeled amount) or 3.3 μg/mm2 (measured amount) of paclitaxel were inflated in peripheral arteries of Yorkshire swine. Arteries received a clinical dose via a single treatment of inflation for 60 seconds. Animals were euthanized from 1 h to 30 days post-treatment and subjected to comprehensive necropsies. The PTX coated balloons were collected for analysis of paclitaxel release, and treated arteries, along with other tissues, were collected for bioanalysis or processed for histologic and scanning electron microscopy (SEM) evaluation.
Additionally, PTX coated balloons (5 mm×40 mm and 6 mm×40 mm ePTFE—W.L. Gore, Flagstaff Ariz.) with dose densities of 3.5 μg/mm2 were inflated and deflated at a benchtop. PTX coated balloons (Commercial) with dose densities of 3.5 μg/mm2 were inflated and deflated at a benchtop. Particulates of the coating from each balloon were collected for analysis after the inflation/deflation.
Results: As shown in
While the PTX coated balloons (Commercial) delivered a greater initial PTX dose compared to that of the PTX coated balloons according to embodiments of the disclosure (ePTFE—W.L. Gore, Flagstaff Ariz.) (an ePTFE/Commercial ratio of 0.6), the PTX coated balloons (ePTFE—W.L. Gore, Flagstaff Ariz.) were able to achieve a 3.8 fold greater maximum retainable dose at 1 hour compared to the PTX coated balloons (Commercial) (an ePTFE/Commercial ratio of 3.8) and a 1.6 fold greater maximum retainable dose at 1 day compared to the PTX coated balloons (Commercial) (an ePTFE/Commercial ratio of 1.6). Although one skilled in the art would expect that the PTX coated balloons (Commercial) delivering a higher initial dose of PTX over that of the PTX coated balloons (ePTFE—W.L. Gore, Flagstaff Ariz.) would also have a higher retainable dose at 1 hour or 1 day over that of the PTX coated balloons (ePTFE—W.L. Gore, Flagstaff Ariz.), the results of DCBs with a fluoropolymer surface and a microcrystalline surface coating morphology provided a synergistic increase in tissue retention.
Surprisingly, the fluoropolymer surface and a microcrystalline surface coating morphology of the PTX coated balloons (ePTFE—W.L. Gore, Flagstaff Ariz.) produced a 3.8-fold higher retainable drug delivery at 1 hour and a 1.6-fold higher retainable drug delivery at 1 day over that of the PTX coated balloons (Commercial). Moreover, the PTX coated balloons (ePTFE—W.L. Gore, Flagstaff Ariz.) showed no signs of particulation after inflation/deflation at a benchtop, whereas the PTX coated balloons (Commercial) demonstrated particulation.
Conclusions: Overall, treatment in peripheral arteries with DCB embodiments of this disclosure at a dose density of 3.5 μg/mm2, resulted in acceptable acute device performance, no adverse safety events, and pharmacokinetics similar to other PTX coated balloons. Imaging of the balloon surfaces coated with similar paclitaxel doses (3.5 μg/mm2) revealed different morphologies. Tissue retention from embodiments of this disclosure benefits from the fluoropolymer surface and a microcrystalline surface coating morphology of the coated balloons but not due to increased dose exposure. The microcrystalline surface coating morphology in some manner may decrease particulation and increase tissue retention of the drug. The similar clearance rates may be attributable to similar tissue clearance mechanisms for both type of DCBs, which demonstrates the importance of early delivery and retention of the drug.
The preclinical performance of an embodiment of a DCB was evaluated, where paclitaxel (PTX) was applied a surface of the balloon.
Methods: PTX coated balloons comprising a fluoropolymer and a coating according to embodiments of the present disclosure (5 mm×40 mm and 6 mm×40 mm ePTFE—W.L. Gore, Flagstaff Ariz.) with dose densities of 4.1 μg/mm2 (5 mm×40 mm balloon) or 3.6 μg/mm2 (6 mm×40 mm balloon), were inflated for 60 seconds in peripheral arteries of 9 Yorkshire swine (target balloon-to-artery ratio between 1.05:1-1.2:1). PTX coated balloons comprising nylon and a coating according to embodiments of the present disclosure (5 mm×40 mm and 6 mm×40 mm nylon—W.L. Gore, Flagstaff Ariz.) with dose densities of 4.1 μg/mm2 (5 mm×40 mm balloon) or 3.6 μg/mm2 (6 mm×40 mm balloon) were inflated for 60 seconds in peripheral arteries of 9 Yorkshire swine (target balloon-to-artery ratio between 1.05:1-1.2:1). Comparative (commercial) PTX coated commercial balloons comprising nylon and a commercial coating with a dose density of 3.5 μg/mm2 were inflated for 60 seconds in peripheral arteries of 9 Yorkshire swine (target balloon-to-artery ratio between 1.05:1-1.2:1. Vessels were harvested at 1 hour, 24 hours, and 72 hours after treatment and were bisected, mounted and processed for scanning electron microscopy to quantify enface tissue coating. Paclitaxel amount in the harvested tissue was measured post imaging.
Results: DCB treatments were successful in peripheral vessels. As shown in
Conclusions: Overall, treatment in peripheral arteries with DCB embodiments of this disclosure resulted in acceptable acute device performance, no adverse safety events, and pharmacokinetics similar to other PTX coated balloons. Imaging of the balloon surfaces coated with similar paclitaxel doses revealed different morphologies, and imaging of treated surfaces of peripheral arteries of the Yorkshire swine revealed different coating efficiencies that correlated with the different paclitaxel delivery and retention. Tissue retention from embodiments of this disclosure benefits from the fluoropolymer surface and a microcrystalline surface coating morphology of the coated balloons but not due to increased dose exposure. While all balloons had similar tissue concentrations at 1 hour post treatment, the PTX ePTFE balloon (W.L. Gore) achieved approximately 2 to 3 times the tissue concentration of the PTX commercial nylon balloon and PTX coated nylon balloons according to embodiments of the disclosure, respectively, at 3 days.
The preclinical performance of a drug coating formulation prepared in accordance with some aspects discussed herein was evaluated for treating various types of ePTFE microstructures and Nylon.
Methods: An ePTFE precursor film (A) that was amorphously locked and generally made in accordance with U.S. Pat. No. 3,953,566 had the following properties: thickness of approximately 25 μm, mass per area of approximately 9 g/m2, and a bubble point of approximately 14 kPa. An ePTFE precursor film (B) that was amorphously locked had the following properties: thickness of approximately 0.0017 inch, mass per area of approximately 6.23 gsm, and a bubble point of approximately 0.41 psi. An ePTFE precursor film (C) that was amorphously locked had the following properties: thickness of approximately 0.00025 inch, mass per area of approximately 2.66 gsm, and a bubble point of approximately 20.38 psi. Tubular members of the ePTFE precursor films were generally made in accordance with U.S. Patent Application Publication No. 2016/0106961. For example, in forming circumferentially wrapped tubular members, in some embodiments, the ePTFE precursor film material was cut into a wide sheet or tape, wherein the strongest direction was transverse to the length of the tape and the strongest direction was oriented axially in the formed balloon. In other circumferentially wrapped embodiments, the strongest direction was along the length of the sheet or tape such that the strongest direction was oriented circumferentially in the formed balloon. For forming helically wrapped tubular members, the precursor material was cut into a tape, wherein the strongest direction was along the length of the tape.
Additionally, PTX coated balloons (W.L. Gore, Flagstaff Ariz.) with dose densities of 3.5 μg/mm2 (5×40 mm) were generally made from the tubular members of the ePTFE precursor films and Nylon in accordance with U.S. Patent Application Publication No. 2016/0106961. The PTX coated balloons were inflated in peripheral arteries of Yorkshire swine. Arteries received a clinical dose via a single treatment of inflation for 60 seconds. Animals were euthanized from 1 h to 30 days post-treatment and subjected to comprehensive necropsies. The PTX coated balloons were collected for analysis of paclitaxel release, and treated arteries, along with other tissues, were collected for bioanalysis or processed for histologic and scanning electron microscopy (SEM) evaluation.
Results: As shown in
Conclusions: The data shows that a range of ePTFE microstructures can be coated and used to deliver a drug such as paclitaxel to a treatment site. Additionally, the data suggests that Nylon DCBs, as compared to ePTFE DCBs, demonstrated a greater degree of particulation. However, overall, the data is conclusive that both a range of ePTFE microstructures and Nylon can be coated with formulations prepared in accordance with some aspects discussed herein and used to deliver a drug to a treatment site.
While the invention has been described in detail, modifications within the spirit and scope of the invention will be readily apparent to the skilled artisan. It should be understood that aspects of the invention and portions of various embodiments and various features recited above and/or in the appended claims may be combined or interchanged either in whole or in part. In the foregoing descriptions of the various embodiments, those embodiments which refer to another embodiment may be appropriately combined with other embodiments as will be appreciated by the skilled artisan. Furthermore, the skilled artisan will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention.
The present application claims priority and benefit from U.S. Provisional Application No. 62/354,636, filed Jun. 24, 2016, entitled “FLUOROPOLYMER BALLOON CATHETER DEVICE AND METHOD FOR INCREASING ARTERIAL PERMEABILITY AND DRUG RETENTION,” U.S. Provisional Application No. 62/414,459, filed Oct. 28, 2016, entitled “FLUOROPOLYMER BALLOON CATHETER DEVICE AND METHOD FOR INCREASING ARTERIAL PERMEABILITY AND DRUG RETENTION,” U.S. Provisional Application No. 62/421,112, filed Nov. 11, 2016, entitled “FLUOROPOLYMER BALLOON CATHETER DEVICE AND METHOD FOR INCREASING ARTERIAL PERMEABILITY AND DRUG RETENTION,” U.S. Provisional Application No. 62/438,547, filed Dec. 23, 2016, entitled “FLUOROPOLYMER BALLOON CATHETER DEVICE AND METHOD FOR INCREASING ARTERIAL PERMEABILITY AND DRUG RETENTION,” U.S. Provisional Application No. 62/439,351, filed Dec. 27, 2016, entitled “FLUOROPOLYMER BALLOON CATHETER DEVICE AND METHOD FOR INCREASING ARTERIAL PERMEABILITY AND DRUG RETENTION,” and U.S. Provisional Application No. 62/488,646 filed Apr. 21, 2017, entitled “FLUOROPOLYMER BALLOON CATHETER DEVICE AND METHOD FOR INCREASING ARTERIAL PERMEABILITY AND DRUG RETENTION,” the entire contents of which are incorporated herein by reference for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 62488646 | Apr 2017 | US | |
| 62439351 | Dec 2016 | US | |
| 62438547 | Dec 2016 | US | |
| 62421112 | Nov 2016 | US | |
| 62414459 | Oct 2016 | US | |
| 62354636 | Jun 2016 | US |
