Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L29/00—Materials for catheters, medical tubing, cannulae, or endoscopes or for coating catheters
  • A61L29/08—Materials for coatings
  • A61L29/085—Macromolecular materials
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L29/00—Materials for catheters, medical tubing, cannulae, or endoscopes or for coating catheters
  • A61L29/14—Materials characterised by their function or physical properties, e.g. lubricating compositions
  • A61L29/145—Hydrogels or hydrocolloids
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L29/00—Materials for catheters, medical tubing, cannulae, or endoscopes or for coating catheters
  • A61L29/14—Materials characterised by their function or physical properties, e.g. lubricating compositions
  • A61L29/16—Biologically active materials, e.g. therapeutic substances

Definitions

• the presently disclosed subject matter is related to the delivery of therapeutic agents from an interventional medical device. More particularly, the presently disclosed subject matter relates to delivery of therapeutic agents from an expandable member, such as a balloon, using a crosslinkable compound capable of being crosslinked on a vessel wall.
• Atherosclerosis is a syndrome affecting arterial blood vessels. It leads to a chronic inflammatory response in the walls of arteries, which is in large part due to the accumulation of lipid, macrophages, foam cells and the formation of plaque in the arterial wall. Atherosclerosis is commonly referred to as hardening of the arteries although the
• Angioplasty is a vascular interventional technique involving mechanically widening an obstructed blood vessel, typically caused by atherosclerosis.
• angioplasty a catheter having a tightly folded balloon is inserted into the vasculature of the patient and is passed to the narrowed location of the blood vessel at which point the balloon is inflated to a fixed size using an inflation fluid, typically a solution of angiographic contrast media.
• PCI Percutaneous coronary intervention
• coronary angioplasty is a therapeutic procedure to treat the stenotic coronary arteries of the heart, often found in coronary heart disease.
• peripheral angioplasty commonly known as percutaneous transluminal angioplasty (PTA) refers to the use of mechanical widening of blood vessels other than the coronary arteries.
• PTA is most commonly used to treat narrowing of the arteries of the leg, especially, the iliac, external iliac, superficial femoral and popliteal arteries. PTA can also treat narrowing of veins and other blood vessels.
• a stent is a device, typically a metal tube or scaffold, which was inserted into the blood vessel following angioplasty, in order to hold the blood vessel open.
• stents While the advent of stents eliminated many of the complications of abrupt vessel closure after angioplasty procedures, within about six months of stenting, a re-narrowing of the blood vessel can form, which is a condition known as restenosis. Restenosis was discovered to be a response to the injury of the angioplasty procedure and is characterized by a growth of smooth muscle cells— analogous to a scar forming over an injury.
• drug eluting stents were developed to address the reoccurrence of the narrowing of blood vessels.
• a drug eluting stent is a metal stent that has been coated with a drug that is known to interfere with the process of restenosis.
• a potential drawback of certain drug eluting stents is known as late stent thrombosis, which is an event in which blood clots form inside the stent.
• Drug coated balloons are believed to be a viable alternative to drug eluting stents in the treatment of atherosclerosis.
• restenosis and the rate of major adverse cardiac events such as heart attack, bypass, repeat stenosis, or death in patients treated with drug coated balloons and drug eluting stents
• the patients treated with drug coated balloons experienced only 3.7 percent restenosis and 4.8% MACE as compared to patients treated with drug eluting stents, in which restenosis was 20.8 percent and 22.0 percent MACE rate.
• drug coated balloons are a viable alternative and in some cases may have greater efficacy than drug eluting stents as suggested by the PEPCAD II study, drug coated balloons present challenges due to the very short period of contact between the drug coated balloon surface and the blood vessel wall.
• the drug delivery time period for a drug coated balloon differs from that of a controlled release drug eluting stent, which is typically weeks to months.
• the balloon may only be inflated for less than one minute, and is often inflated for only thirty seconds. Therefore, an efficacious, therapeutic amount of drug must be transferred to the vessel wall within a thirty-second to one-minute time period.
• the allowable inflation times can be greater than one minute, but are still measured in minutes.
• there are challenges specific to drug delivery via a drug coated balloon because of the necessity of a short inflation time, and therefore time for drug or coating transfer— a challenge not presented by a drug eluting stent, which remains in the patient's vasculature once implanted.
• Tissue retention will depend on several factors, including characteristics of the therapeutic agent and the formulation of the balloon coating. Such retention will permit greater local drug uptake, thereby improving treatment efficacy and decreasing systemic exposure to the therapeutic agent.
• a system includes an expandable member having a distal end, a proximal end and a working length therebetween, a crosslinkable compound capable of being crosslinked after intraluminal release onto a vessel wall disposed along at least a portion of the working length, and at least one therapeutic agent disposed along the portion of the working length so as to be temporarily retained by the crosslinkable compound after intraluminal release to the vessel wall.
• the therapeutic agent is selected from the group consisting of antithrombotics, anticoagulants, antiplatelet agents, anti- lipid agents, thrombolytics, antiproliferatives, anti-inflammatories, agents that inhibit hyperplasia, smooth muscle cell inhibitors, antibiotics, growth factor inhibitors, cell adhesion inhibitors, cell adhesion promoters, cytostatic drugs, antimitotics, antifibrins, antioxidants, antineoplastics, agents that promote endothelial cell recovery, antiallergic substances, viral vectors, nucleic acids, monoclonal antibodies, antisense compounds, oligonucleotides, cell permeation enhancers, radiopaque agent markers, HMG Co A reductase inhibitors, pro-drugs, and combinations thereof.
• the crosslinkable compound can be disposed as a coating on the expandable member, such as an outer layer containing a therapeutic agent or agents.
• the expandable member can have an outer surface with reservoirs containing the crosslinkable compound for intraluminal release.
• the expandable member can have pores along the portion of the working length, such that the crosslinkable compound is released through the pores.
• the therapeutic agent or agents can also be located within the reservoirs or pores for intraluminal release upon inflation.
• the crosslinkable compound is crosslinked by thermal treatment.
• the compound can crosslink at a temperature of 37 degrees Celsius or above.
• Compounds of such embodiments can be selected from the group consisting of silk-elastin-like protein-based polymers, pluronics F127, pluronics F68, poly N-isopropylacrylamide
• polyNIPAAM polyNIPAAM-co-acrylic acid
• PEG-PEG-PLA-PEG polyNIPAAM-co-acrylic acid
• PLGA-PEG polyNIPAAM-co-acrylic acid
• solubilized extracellular matrix solubilized extracellular matrix
• self-assembling peptides hydroxypropylmethylcellulose, or a combination thereof.
• a heat source can also be provided with the system of these embodiments to heat the compound on the vessel wall to a temperature above 37 degrees Celsius after intraluminal delivery.
• the crosslinkable compound is crosslinked by melt thermal treatment.
• the crosslinkable compound of such embodiments can crosslink at or below about 37 degrees Celsius.
• Compounds of these embodiments can be selected from the group consisting of poly(s -caprolactone), poly(ortho esters) and
• a heat source can be provided with the system of these embodiments to heat the compound to a temperature above 37 degrees Celsius for intraluminal release from the balloon, and subsequent cooling and crosslinking on the vessel wall.
• the crosslinkable compound of the present invention is crosslinked by solvation.
• Compounds of these embodiments can be selected from the group consisting of poly(ester amide), poly(lactic-co-glycolic acid) (“PLGA”), poly-DL-lactide (“PDLLA”), poly-L-lactide (“PLLA”), PLGA-polyethylene glycol (“PEG”)-PLGA, PLLA-PEG- PLLA, and a combination thereof.
• Suitable solvents for these embodiments include N- methylpyrrolidinone, dimethyl sulfoxide, and dichloromethane.
• the solvent and the crosslinkable compound can be delivered independently along the working length of the expandable member, for example in the reservoirs described above and applied as a coating respectively, and combined at the site of delivery.
• the crosslinkable compound is shear-sensitive so as to crosslink upon removal of shear associated with inflation at the site of delivery and/or intraluminal release to the vessel wall.
• Crosslinkable compounds of these embodiments can be selected from the group consisting of sodium hyaluronate, sodium alginate, and certain lightly crosslinked hydrogels such as lightly crosslinked sodium alginate, lightly crosslinked sodium hyaluronate/methylcellulose blends, or a combination thereof.
• a crosslinkable compound capable of crosslinking within a pH range of between about 6.8 and about 7.4.
• Crosslinkable compounds of these embodiments can be selected from the group consisting of acid-soluble collagen, chitosan, polyacrylic acid, or a combination thereof.
• the crosslinkable compound is crosslinked by chemical reaction with a second compound.
• the second compound is disposed along at least a portion of the working length of the expandable member.
• Crosslinkable compounds of these embodiments can be selected from the group consisting of PEG N- hydroxysuccinamide ("NHS") ester, PEG acrylate, PEG amine, PEG thiol, sodium hyaluronate acrylate, hyaluronate thiol, fibrin, and methacrylate modified acrylate.
• the compounds of these embodiments can be selected so as to be chemically reactive in an environment having a predetermined pH range. In one aspect, the predetermined pH is at least about 6.8.
• the crosslinkable compound is crosslinked by photoactivation.
• Crosslinkable compounds of these embodiments can be selected from the group consisting of 2-hydroxy-l [4-(hydroxyethoxy)phenyl]-2-methyl-l- propanone, PEG acrylate, methacrylate modified alginate, methacrylate modified hyaluronan, and a combination thereof.
• the system of such embodiments can include a light source to crosslink the compound by photoactivation.
• photoactivation can also be disposed along the working length of the expandable member.
• the crosslinkable compound can be crosslinked by ionic crosslinking.
• Suitable crosslinkable compounds can be selected from the group consisting of sodium alginate, pectin, aloe pectin, and a combination thereof.
• a second compound optionally can be disposed on at least a portion of the working length of the expandable member, wherein the second compound is selected from the group consisting of calcium chloride, barium chloride, and a combination thereof. In this manner, the second compound dissociates into corresponding component ions to crosslink the crosslinkable compound at the site of delivery.
• the disclosed subject matter includes a method of delivering a therapeutic agent to a vessel wall of a body lumen.
• the method includes providing a system corresponding to an embodiment described above, positioning the expandable member in a body lumen, expanding the expandable member to contact the vessel wall for intraluminal release of the crosslinkable compound onto the vessel wall, and crosslinking the crosslinkable compound on the vessel wall such that the therapeutic agent or agents are temporarily retained by the crosslinked compound at the vessel wall.
• FIGURE 1A is a schematic view of one representative balloon catheter in accordance with the disclosed subject matter.
• FIGURE IB is a schematic cross-sectional end view taken along lines A-A in FIGURE 1A.
• FIGURE 1C is a schematic cross-sectional end view taken along lines B-B in FIGURE 1A.
• FIGURE 2 is a schematic side view representation of the disclosed method for delivering therapeutic agent to a body lumen, wherein FIGURE 2A is a schematic side view of a stenotic arterial blood vessel; FIGURE 2B is a schematic side view of the same vessel after insertion of the expandable member catheter of FIGURE 1; FIGURE 2C is a schematic side view of the vessel after inflation of the expandable member catheter and intraluminal release of the therapeutic agent and crosslinkable compound; and FIGURE 2D is a schematic side view of the vessel after inflation of the expandable member catheter with the crosslinkable compound crosslinked on the vessel wall.
• FIGURE 3 is a schematic cross-sectional representation of the disclosed method of FIGURE 2, wherein FIGURE 3A is a schematic cross-sectional view of a stenotic arterial blood vessel; FIGURE 3B is a schematic cross-sectional view of the same vessel after insertion of the expandable member catheter of FIGURE 1; FIGURE 3C is a schematic cross-sectional view of the vessel after inflation of the expandable member catheter and intraluminal release of the therapeutic agent and crosslinkable compound; and FIGURE 3D is a schematic cross- sectional view of the vessel after inflation of the expandable member catheter with the crosslinkable compound crosslinked on the vessel wall.
• the methods and systems presented herein can be used to deliver a therapeutic agent to a vessel wall of a body lumen.
• the disclosed subject matter is particularly suited for applying therapeutic agents to a vessel wall of a body lumen in a manner that promotes retention of the therapeutic agent at the site of delivery.
• the disclosed subject matter provides a system, and corresponding method, to deliver a therapeutic agent to a vessel wall of a body lumen, whereby the therapeutic agent is retained at the site of delivery by a crosslinkable compound.
• the delivery systems and corresponding methods deliver a therapeutic agent to the body lumen via an expandable member.
• the expandable member deposits the therapeutic agent and crosslinkable compound by temporary contact with the vessel wall of the body lumen.
• the crosslinkable compound is crosslinked after delivery to the body lumen as disclosed herein to promote retention and delivery of the therapeutic agent at the site of delivery.
• a system for delivering a therapeutic agent to a vessel wall of a body lumen includes an expandable member having a distal end, a proximal end, and a working length therebetween.
• the expandable member has disposed along at least a portion of its working length a
• crosslinkable compound for intraluminal release from the expandable member after inflation.
• the crosslinkable compound of the system is capable of being crosslinked after intraluminal release onto a vessel wall.
• the expandable member also includes at least one therapeutic agent disposed along a portion of its working length so as to be temporarily retained by the
• crosslinkable compound after intraluminal release to the vessel wall.
• a method of delivering a therapeutic agent to a vessel wall of a body lumen includes providing a system including an expandable member having a distal end, a proximal end and a working length therebetween.
• a crosslinkable compound disposed along at least a portion of the working length of the expandable member, and at least one therapeutic agent disposed along the portion of the working length so as to be temporarily retained by the crosslinkable compound after intraluminal release to the vessel wall.
• the expandable member is positioned within a body lumen and then expanded to contact the vessel wall for intraluminal release of the crosslinkable compound to the vessel wall.
• the crosslinkable compound is crosslinked on the vessel wall with the at least one therapeutic agent temporarily retained by the crosslinked compound for delivery to the vessel wall.
• the terms “comprising,” “including,” and “having” can also be used interchangeably.
• the terms “amount” and “level” are also interchangeable and can be used to describe a concentration or a specific quantity.
• the term “selected from the group consisting of refers to one or more members of the group in the list that follows, including mixtures (i.e. combinations) of two or more members.
• the term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can mean within 3 or more than 3 standard deviations, per the practice in the art. Alternatively, “about” can mean a range of up to +/-20%, or up to +/- 10%, or up to +1-5%, or up to +/-1% of a given value. Alternatively, particularly with respect to biological systems or processes, the term can mean within an order of magnitude, or within 5-fold, or within 2-fold, of a value. With reference to pharmaceutical compositions, the term “about” refers to a range that is acceptable for quality control standards of a product approved by regulatory authorities.
• the systems and methods presented can be used for delivery of a therapeutic agent to a vessel wall of a subject.
• the methods and systems presented herein can also be used for manufacture and assembly of medical devices such as a drug coated balloon catheter. While the disclosed subject matter references application of a therapeutic agent, it is to be understood that a variety of coatings including polymeric, therapeutic, or matrix coatings, can be applied to various surfaces of medical devices, as so desired.
• the balloon catheter device 10 generally includes an elongated catheter shaft 12 having a proximal end and having a distal end and an expandable member or balloon 30 located proximate to the distal end of the catheter shaft.
• a crosslinking source 50 is applied to at least a portion of the working length of the balloon catheter.
• the expandable balloon has an outer surface and an inner surface disposed at the distal end portion of the catheter shaft.
• an elongated catheter shaft 12 having a coaxial arrangement comprising an outer tubular member 14 and an inner tubular member 16.
• the outer tubular member 14 defines an inflation lumen 20 disposed between the proximal end portion and the distal end portion of the catheter shaft 12.
• the coaxial relationship between the inner tubular member 16 and the outer tubular member 14 defines an annular inflation lumen 20.
• the expandable member 30 is in fluid communication with the inflation lumen 20. The inflation lumen therebetween can supply fluid under pressure to the expandable member 30, and establish negative pressure to draw fluid from the expandable member 30. The expandable member 30 can thus be inflated and deflated.
• the elongated catheter is sized and configured for delivery through a tortuous anatomy, and can further include a guidewire lumen 22 that permits it to be delivered over a guidewire 18.
• the inner tubular member 16 defines the guidewire lumen 22 for the guidewire 18.
• FIGURES 1A and IB illustrate the guidewire lumen as having an over-the-wire (OTW) construction
• the guidewire lumen can be configured as a rapid-exchange (RX) construction, as is well known in the art.
• the shaft can be provided as a multilumen member, or composition of two or more tubular members, as is known in the art.
• the expandable member or balloon 30 has a distal end 32, a proximal end 34 and a working length "L" therebetween.
• the expandable member embodied herein has a an interior chamber 36 in fluid communication with the inflatable lumen 20 of the elongated shaft 12. Any of a number of suitable expandable member constructions and shapes can be used, as described further below.
• At least one therapeutic agent 40 is disposed along at least a portion of the working length "L" of the expandable member 30.
• the at least a portion of the working length can be a selected length of the working length or the working length in its entirety. Furthermore, the at least a portion can reference a pattern on the surface of the working length, such as rings, dots, linear or curvilinear segments, or another design.
• the at least one therapeutic agent can be disposed along the portion of the working length of the expandable member in any suitable manner that will allow for release from the expandable member to the vessel wall. For example, the at least one therapeutic agent can be applied as a coating to the outer surface of the expandable member. Additionally or
• the expandable member can be provided with reservoirs or similar surface features to contain therapeutic agent for release therefrom. Furthermore, pores or channels can be defined along a portion of the working length for infusion-type release of the therapeutic agent therefrom.
• the at least one therapeutic agent can be disposed alone, e.g., neat, or in combination with a suitable additive, such as a surfactant, plasticizer or the like. Additionally, and as described further below, the at least one therapeutic agent can be disposed for delivery in combination with a crosslinkable compound 60.
• the therapeutic agent can be applied as a layer over a layer of the crosslinkable compound, and/or the therapeutic agent can be mixed with the crosslinkable compound as appropriate.
• a crosslinkable compound is disposed along at least a portion of the expandable member.
• the crosslinkable compound Upon inflation of the expandable member within the body lumen, the crosslinkable compound is transferred from the outer surface of the expandable member to the wall of the lumen.
• the crosslinkable compound can be crosslinked to retain the therapeutic agent at the site of delivery.
• the crosslinkable compound can be disposed along the portion of the working length in a variety of suitable manners.
• the crosslinkable compound can be applied as a coating on an outer surface of the expandable member, and/or can be confined in reservoirs or the like defined in the outer surface.
• crosslinkable compound can be disposed for delivery from the expandable member through pores, channels or the like defined thereon.
• crosslinking source 50 can be provided to crosslink the crosslinkable compound 60 after delivery or release from the expandable member onto the vessel wall if needed.
• the crosslinking source 50 will depend on the crosslinkable compound 60 to be used, as described further below. Examples of such crosslinking sources can include, but are not limited to, heat source, light source and/or independent source of delivering a solvent or crosslinking agent, as described further below.
• the crosslinking source 50 depicted herein is provided on the expandable member used for delivery of the therapeutic agent 40 and/or crosslinkable compound 60, it is recognized that the crosslinking source 50 can be provided spaced from the expandable member, or can be provided on a separate catheter as desired or appropriate.
• the crosslinkable compound can be disposed as a coating on the outer surface of the expandable member.
• the coating of the expandable member can further include an outer layer containing at least one therapeutic agent.
• the therapeutic agent can be combined or mixed with the crosslinkable compound as a coating on the outer surface of the expandable member.
• the coating containing the at least one therapeutic agent is transferred to the wall of the body lumen. If the therapeutic agent is disposed as a separate outer layer, then the crosslinkable compound is disposed over the therapeutic agent on the vessel wall.
• the crosslinkable compound is subsequently crosslinked to temporarily retain the therapeutic agent at the site of delivery.
• the site of delivery can be, for example, a stenotic lesion, although the site can be any suitable body lumen where delivery of a therapeutic agent is desired.
• FIGURES 2A and 3A show a stenotic arterial vessel.
• An expandable member 30 according to the present invention is introduced as shown in
• FIGURES 2B and 3B The expandable member 30 is expanded as shown in FIGURES 2C and 3C to deliver the therapeutic agent 40 and crosslinkable compound 60 to the vessel wall.
• the therapeutic agent 40 is transferred to the vessel wall and the crosslinkable compound 60 is disposed over the therapeutic agent on the vessel wall.
• the crosslinkable compound 60 can then be crosslinked using a suitable
• crosslinking source 50 either disposed on the expandable member or on a separate catheter as desired.
• the crosslinkable compound 60 is thus retained on the vessel wall after removal of the expandable member, and the therapeutic agent 40 can then be absorbed at the site of delivery.
• the expandable member can have an outer surface with reservoirs or similar features defined along a portion of the working length of the member.
• the crosslinkable compound thus can be disposed for intraluminal release within the reservoirs.
• the crosslinkable compound and/or at least one therapeutic agent is released from the reservoirs and transferred to the vessel wall of the body lumen.
• the crosslinking compound can be disposed in a first set of reservoirs and the therapeutic agent can be disposed in a second set of reservoirs.
• the crosslinking compound can be mixed with or disposed as a first layer within the reservoirs and the therapeutic agent can be disposed as a second layer within the same reservoirs as the crosslinking compound.
• an infusion technique can be used for delivery of the crosslinking compound and/or therapeutic agent.
• the expandable member can have pores or channels defined therein along a portion of the working length, wherein the
• crosslinkable compound and/or at least one therapeutic agent is disposed for intraluminal release through the pores.
• the crosslinkable compound and/or at least one therapeutic agent can be extruded or otherwise released through the pores or channels and transferred to vessel wall of the body lumen.
• the crosslinking compound and therapeutic agent can be disposed for release through separate pores, or mixed for delivery together through the same pores.
• the at least one therapeutic agent can be delivered in combination with the crosslinking compound , wherein the therapeutic agent or agents is trapped within the crosslinked compound after crosslinking.
• the therapeutic agent or agents thus can be released over time into the vessel wall as desired.
• the therapeutic agent or agents can be delivered according to the exemplary embodiments provided so as to be confined against or forced into the vessel wall by the crosslinked material.
• the crosslinkable compound can be crosslinkable by thermal treatment.
• Thermal treatment generally refers to the transfer of thermal energy from an extrinsic or intrinsic source to the crosslinkable compound.
• Suitable compounds crosslinkable by thermal treatment include, but are not limited to, silk-elastin-like protein-based polymers, pluronics F127, pluronics F68, poly-NIPAAM, poly-NIPAAM-co- acrylic acid, PEG-PEG-PLA-PEG, PLGA-PEG,PLGA, solubilized extracellular matrix, self- assembling peptides, hydroxypropylmethylcellulose, and a combination thereof.
• Such thermally crosslinkable compounds generally can crosslink at or above about 37 degrees Celsius, such as by a heat source disposed on or proximate the expandable member.
• thermally crosslinkable compounds are advantageous in that only one compound is required for crosslinking, although additional additives or potentially reactive compounds can be used but are necessarily required.
• the crosslinkable compound is delivered by, for example, one of the exemplary techniques above, and subsequently crosslinked at the site of delivery by thermal filaments or other suitable heat source on the expandable member to crystallize irreversibly to a ⁇ -sheet configuration.
• Such a stable crosslinked configuration provides improved retention of the crosslinkable compound and therapeutic agent(s) upon the vessel wall.
• the crosslinkable compound can be a liquid at room temperature and gelate at body temperature. Upon catheter delivery and inflation, gelation at body temperature permits retention of the compound at the site of delivery.
• the crosslinkable compound can be crosslinked by melt thermal treatment.
• Melt thermal treatment generally refers to heat melting of a polymer in vivo or ex vivo. Suitable melt thermal polymers subsequently crosslink as they re-solidify. Melt thermal crosslinkable compounds include but are not limited to poly(s -caprolactone), poly(ortho esters),
• melt thermal crosslinkable compounds can crosslink at or below about 37 degrees Celsius.
• the crosslinking source for such melt thermal crosslinkable compounds can include a heat source to heat the melt thermal crosslinkable compound to a temperature above about 37 degrees Celsius prior to delivery and release from the expandable member.
• the crosslinkable compound can be delivered in the form of a polymer melt above a T m of about 60 degrees Celsius or heated in situ to a temperature above about 60 degrees Celsius. After release from the expandable member onto the vessel wall, the crosslinkable compound then solidifies at body temperature and crosslinks to permit retention of the compound at the site of delivery.
• the crosslinkable compound is crosslinked by photoactivation.
• Photoactivation generally refers to the application of light or electromagnetic energy of a suitable wavelength and intensity, such as the visible or ultraviolet portion of the electromagnetic spectrum, to the crosslinkable compound during or after delivery.
• Suitable crosslinkable compounds capable of being crosslinked by photoactivation include, but are not limited to, PEG diacrylate and 2- hydroxy-l-[4-(hydroxyethoxy)phenyl]-2-methyl-l-propanone (Irgacure 2959 ® ).
• Suitable photoactivators for such compounds include, but are not limited to, ultraviolet light.
• the crosslinking source is provided as a light source as a component of the catheter assembly, or as a separate catheter component.
• the crosslinkable compound is crosslinked by solvation.
• “Solvation” as used herein generally refers to the introduction or application of solvent to the crosslinkable compound before, during, or after delivery.
• Suitable crosslinkable compounds which are crosslinked by solvation include but are not limited to poly(ester amide) ("PEA”), PLGA, PDLLA, PLLA, PLGA-PEG-PLGA, PLLA-PEG-PLLA, N-methylpyrrolidinone, dimethyl sulfoxide, dicholoromethane, and a combination thereof.
• PDA poly(ester amide)
• PLGA poly(ester amide)
• PDLLA poly(ester amide)
• PLLA PLGA-PEG-PLGA
• PLLA-PEG-PLLA N-methylpyrrolidinone
• dimethyl sulfoxide dicholoromethane
• dicholoromethane and a combination thereof.
• Such compounds readily dissolve hydrophobic drugs and therefore
• a crosslinked formulation incorporating the desired hydrophobic drug(s) can be formed at the site of balloon inflation.
• PEA can be delivered to the vessel wall of the body lumen in accordance with a delivery system described herein, and crosslinked by solvation using N-methylpyrrolidinone to form a crosslinked formulation retained on the vessel wall at the site of delivery.
• the crosslinking source can be one or more pores for the release of the solvent into or in combination with the crosslinkable compound.
• the crosslinkable compound provided is shear- sensitive so as to crosslink upon removal of shear stress.
• removal of shear stress can occur upon intraluminal release of the crosslinkable compound to the vessel wall.
• Suitable shear- sensitive crosslinkable compounds include but are not limited to sodium hyaluronate (for example, Healon5 ® ) and sodium alginate, as well as certain lightly crosslinked hydrogels such as lightly crosslinked sodium alginate and sodium hyaluronate methylcellulose blends, and combinations thereof. These compounds gelate immediately upon removal of shear and thus can be retained on the vessel wall at the site of delivery.
• the crosslinkable compound can be selected to crosslink when exposed to an environment within a pH range of about 6.8 to about 7.4.
• Suitable crosslinkable compounds that crosslink within a pH range of about 6.8 to about 7.4 include, but are not limited to, acid-soluble collagen, chitosan, polyacrylic acid and combinations thereof.
• acidic recombinant collagen can be delivered to the vessel wall of the body lumen according to the embodiments provided herein. Upon contact with the neutral body pH of the vessel wall, the acidic collagen solution neutralizes and gelates, with the therapeutic agent(s) captured therein. The gelated collagen solution is retained on the vessel wall at the site of delivery with the therapeutic agent(s) captured therein.
• the crosslinkable compound is crosslinked by chemical reaction with one or more additional compounds.
• the additional compound(s) can be selected to be chemically reactive with the first crosslinkable compound.
• These additional compounds can be disposed along and/or released from at least a portion of the working length of the expandable member.
• the additional compounds can be disposed in a top coating layer or a base layer.
• the additional compound(s) can be released from reservoirs or pores defined in the expandable member, similar to the solvent described above.
• chemically crosslinkable compounds for delivery by a balloon to temporarily retain one or more therapeutic agents include hydrophilic polymers, peptide hydrogels, carbohydrate hydrogels, and combinations thereof.
• Suitable hydrophilic polymers for chemical crosslinking include, but are not limited to, polyethylene glycol ("PEG"), PLLA-PEG-PLLA copolymers, PLDA-PEG-PLDA copolymers, PLGA-PEG- PLGA copolymers, PEG-PLLA copolymers, PEG-PLDA copolymers, PEG-PLGA copolymers, and combinations thereof.
• Suitable peptide and carbohydrate hydrogel components for chemical crosslinking include alginate, hyaluronic acid, collagen, laminin, poly-l-lysine, fibrin, fibrinogen, gelatin, and combinations thereof.
• the hydrophilic polymers, peptide and carbohydrate hydrogel components can be functionalized with reactive functional groups to promote chemical crosslinking.
• Suitable functional groups include, without limitation, thiol, vinyl, amino, acrylate, methacrylate, aldehyde, vinylsulfone, succinimidyl, hydroxysuccinimidyl, nitrophenolate, and carbohydrazide moieities.
• the crosslinkable compound is functionalized with reactive functional groups.
• both the crosslinkable compound and the additional compound or compounds are functionalized with reactive functional groups.
• only the additional compound or compounds are functionalized with reactive functional groups.
• the crosslinkable compound is crosslinked by a Micheal' s addition reaction.
• the crosslinkable compound can be functionalized with a nucleophile, and the additional compound functionalized with an electrophile.
• a Micheal's addition reaction occurs in situ between the nucleophilic compound and the electrophilic compound to form a crosslinked composite on the vessel wall at the site of balloon inflation.
• Michael's reactions proceed relatively quickly, on the order of seconds to hours, and accordingly are well-suited to crosslinking in situ to retain therapeutic agent at the vessel wall.
• the crosslinkable compound can be crosslinked by the formation of disulfide bonds in an oxidative reaction.
• the crosslinkable compound may be functionalized with thiol residues which form disulfide bonds in oxidizing conditions.
• the additional compound can be an oxidizing compound to promote disulfide bond formation in situ.
• the additional compound or compounds is selected to be chemically reactive with the first crosslinkable compound in an environment having a predetermined pH, which in certain embodiments is at least about 6.8.
• a predetermined pH which in certain embodiments is at least about 6.8.
• an additional compound can be provided to activate the reactive functional groups.
• a basic buffer can be provided in reservoirs on the balloon or channels in the balloon to accelerate crosslinking of the crosslinkable compound by initiating deprotonation of nucleophilic functional groups. In certain embodiments, this buffer has a pH between about 7.0 and about 10.0.
• the crosslinkable compound is a PEG polymer comprised of multi-arm PEG monomers wherein each PEG arm is functionalized with a nucleophilic functional group.
• An additional compound is provided consisting of a PEG polymer comprised of multi-arm PEG monomers wherein each PEG arm is functionalized with an electrophilic functional group.
• suitable nucleophilic functional groups include, without limitation, thiol, amino, hydroxyl, and CO-NH_NH2 groups
• suitable electrophilic functional groups include, without limitation, acrylate, vinylsulfone, and N-hydroxysuccinimide groups.
• the inter-polymer crosslinking chemical reaction results in the formation of biodegradeable covalent bonds, such as ester linkages.
• biodegradeable covalent bonds such as ester linkages.
• the reaction of PEG-acrylate and PEG-thiol results in the formation of thioester bonds, which are readily hydrolyzed in vivo.
• the multi-arm PEG crosslinkable compound has between 1 and 16 arms, and has a linear, comb, branched or star configuration.
• the PEG crosslinkable compound can also have a molecular weight of between about 2 and 40 kDa.
• the additional multi-arm PEG crosslinkable compound has between 1 and 16 arms, has a linear, comb, branched or star configuration, and has a molecular weight of between 2 and 40 kDa.
• the crosslinkable compound is a multi-arm PEG as described above, while the additional compound is a peptide or carbohydrate polymer.
• PEG-NHS ester is delivered to the body lumen as a crosslinkable compound, and gelatin is provided as an additional compound.
• Gelatin is, for example, disposed along the expandable member, and chemically reacts with the PEG-NHS ester to gelate in situ to promote temporary retention of the crosslinkable compound at the site of delivery.
• the crosslinkable compound is a carbohydrate functionalized with reactive functional groups.
• the crosslinkable carbohydrate compound can be sodium hyaluronate acrylate, hyaluronate-thiol, or methacrylate-modified alginate.
• the crosslinkable compound provided is crosslinked by ionic crosslinking.
• a second compound can be provided to effect ionic crosslinking of the crosslinkable compound, and can be disposed along a portion of the working length of the expandable member.
• Suitable crosslinkable compounds which are crosslinked by ionic crosslinking include but are not limited to sodium alginate, pectin, aloe pectin, alginate conjugates, including alginate-collagen and alginate laminin, and combinations thereof.
• Suitable second compounds for ionic crosslinking include but are not limited to calcium chloride, barium chloride, calcium chloride and
• the separate compounds can be delivered as separate layers and/or by infusion through separate pores, and the mechanically mixed upon inflation, or by separate expandable members.
• the therapeutic agent or drug can include any of a variety of suitable anti-proliferative, anti-inflammatory, anti-neoplastic, anti-platelet, anti-coagulant, anti- fibrin, anti-thrombotic, anti-mitotic, antibiotic, anti-allergic and antioxidant compounds.
• the therapeutic agent can be, again without limitation, a synthetic inorganic or organic compound, a protein, a peptide, a polysaccharides and other sugars, a lipid, DNA and RNA nucleic acid sequences, an antisense oligonucleotide, an antibody, a receptor ligands, an enzyme, an adhesion peptide, a blood clot agent including streptokinase and tissue plasminogen activator, an antigen, a hormone, a growth factor, a ribozyme, and a retroviral vector.
• a synthetic inorganic or organic compound a protein, a peptide, a polysaccharides and other sugars, a lipid, DNA and RNA nucleic acid sequences, an antisense oligonucleotide, an antibody, a receptor ligands, an enzyme, an adhesion peptide, a blood clot agent including streptokinase and tissue plasminogen activator,
• anti-proliferative means an agent used to inhibit cell growth, such as chemotherapeutic drugs. Some non-limiting examples of anti-proliferative drugs include taxanes, paclitaxel, docetaxel, and protaxel. Anti-proliferative agents can be anti-mitotic.
• anti-mitotic as used herein means an agent used to inhibit or affect cell division, whereby processes normally involved in cell division do not take place. One sub-class of antimitotic agents includes vinca alkaloids.
• vinca alkaloids include, but are not limited to, vincristine, paclitaxel, etoposide, nocodazole, indirubin, and anthracycline derivatives, including, for example, daunorubicin, daunomycin, and plicamycin.
• anti-mitotic agents include anti-mitotic alkylating agents, including, for example, tauromustine, bofumustine, and fotemustine, and anti-mitotic metabolites, including, for example, methotrexate, fluorouracil, 5-bromodeoxyuridine, 6-azacytidine, and cytarabine.
• Antimitotic alkylating agents affect cell division by covalently modifying DNA, RNA, or proteins, thereby inhibiting DNA replication, RNA transcription, RNA translation, protein synthesis, or combinations of the foregoing.
• An example of an anti-mitotic agent includes, but is not limited to, paclitaxel.
• paclitaxel includes the alkaloid itself and naturally occurring forms and derivatives thereof, as well as synthetic and semi- synthetic forms thereof.
• Anti-platelet agents are therapeutic entities that act by (1) inhibiting adhesion of platelets to a surface, typically a thrombogenic surface, (2) inhibiting aggregation of platelets, (3) inhibiting activation of platelets, or (4) combinations of the foregoing.
• Activation of platelets is a process whereby platelets are converted from a quiescent, resting state to one in which platelets undergo a number of morphologic changes induced by contact with a thrombogenic surface. These changes include changes in the shape of the platelets, accompanied by the formation of pseudopods, binding to membrane receptors, and secretion of small molecules and proteins, including, for example, ADP and platelet factor 4.
• Anti-platelet agents that act as inhibitors of adhesion of platelets include, but are not limited to, eptifibatide, tirofiban, RGD (Arg-Gly-Asp)- based peptides that inhibit binding to gpllbllla or avb3, antibodies that block binding to gpllalllb or avb3, anti-P-selectin antibodies, anti-E-selectin antibodies, compounds that block P-selectin or E-selectin binding to their respective ligands, saratin, and anti-von Willebrand factor antibodies.
• Agents that inhibit ADP-mediated platelet aggregation include, but are not limited to, disagregin and cilostazol.
• At least one therapeutic agent can be an anti-inflammatory agent.
• anti-inflammatory agents include prednisone, dexamethasone, dexamethasone acetate, hydrocortisone, estradiol, triamcinolone, mometasone, fluticasone, clobetasol, and non-steroidal anti-inflammatories, including, for example, acetaminophen, ibuprofen, naproxen, adalimumab and sulindac.
• the arachidonate metabolite prostacyclin or prostacyclin analogs is an example of a vasoactive antiproliferative.
• agents include those that block cytokine activity or inhibit binding of cytokines or chemokines to the cognate receptors to inhibit pro-inflammatory signals transduced by the cytokines or the chemokines.
• Representative examples of these agents include, but are not limited to, anti-ILl, anti-IL2, anti-IL3, anti-IL4, anti-IL8, anti-ILl 5, anti-ILl 8, anti-MCPl, anti-CCR2, anti-GM- CSF, and anti-TNF antibodies.
• Anti-thrombotic agents include chemical and biological entities that can intervene at any stage in the coagulation pathway. Examples of specific entities include, but are not limited to, small molecules that inhibit the activity of factor Xa.
• heparinoid-type agents that can inhibit both FXa and thrombin, either directly or indirectly, including, for example, heparin, heparin sulfate, low molecular weight heparins, including, for example, the compound having the trademark Clivarin®, and synthetic oligosaccharides, including, for example, the compound having the trademark Arixtra®.
• direct thrombin inhibitors including, for example, melagatran, ximelagatran, argatroban, inogatran, and peptidomimetics of binding site of the Phe-Pro-Arg fibrinogen substrate for thrombin.
• factor Vll/VIIa inhibitors including, for example, anti-factor Vll/VIIa antibodies, rNAPc2, and tissue factor pathway inhibitor (TFPI).
• Thrombolytic agents which can be defined as agents that help degrade thrombi
• clots can also be used as adjunctive agents, because the action of lysing a clot helps to disperse platelets trapped within the fibrin matrix of a thrombus.
• thrombolytic agents include, but are not limited to, urokinase or recombinant urokinase, pro- urokinase or recombinant pro-urokinase, tissue plasminogen activator or its recombinant form, and streptokinase.
• the therapeutic agents include a cytostatic agent.
• cytostatic as used herein means an agent that mitigates cell proliferation, allows cell migration, and does not induce cell toxicity.
• cytostatic agents include, for the purpose of illustration and without limitation, macrolide antibiotics, zotarolimus, sirolimus, rapamycin, everolimus, biolimus, myolimus, novolimus, temsirolimus, deforolimus, merilimus, sirolimus derivatives, tacrolimus, pimecrolimus, derivatives and analogues thereof, any macrolide immunosuppressive drugs, and combinations thereof.
• Other therapeutic agents include cytotoxic drugs, including, for example, apoptosis inducers, including TGF, and topoisomerase inhibitors, including, 10- hydroxycamptothecin, irinotecan, and doxorubicin.
• anti-inflammatory drugs include both steroidal and non-steroidal anti-inflammatories (NSAID) such as, without limitation, clobetasol, alclofenac, alclometasone dipropionate, algestone acetonide, alpha amylase, amcinafal, amcinafide, amfenac sodium, amiprilose hydrochloride, anakinra, anirolac, anitrazafen, apazone, balsalazide disodium, bendazac, benoxaprofen, benzydamine hydrochloride, bromelains, broperamole, budesonide, carprofen, cicloprofen, cintazone, cliprofen, clobetasol propionate, clobetasone butyrate, clopirac, cloticasone propionate, cormethasone acetate, cortodoxone, deflazacort, desonide, desoximetas
• flurbiprofen fluretofen, fluticasone propionate, furaprofen, furobufen, halcinonide, halobetasol propionate, halopredone acetate, ibufenac, ibuprofen, ibuprofen aluminum, ibuprofen piconol, ilonidap, indomethacin, indomethacin sodium, indoprofen, indoxole, intrazole, isoflupredone acetate, isoxepac, isoxicam, ketoprofen, lofemizole hydrochloride, lomoxicam, loteprednol etabonate, meclofenamate sodium, meclofenamic acid, meclorisone dibutyrate, mefenamic acid, mesalamine, meseclazone, methylprednisolone suleptanate, momiflumate, nabumetone, naprox
• the agent can include other compounds or additives, such as excipients, binding agents, plasticizers, solvents, surfactants, additives, fillers, and the like.
• examples of possible compounds include polyvinylpyrrolidone, gelatin, maltrodextrin, starch, hydroxypropyl methyl cellulose, glycerol, polyethylene glycol, polysorbates, tweens, polyoxamers, Vitamin E tocopheryl polyethylene glycol succinate ("TPGS”), fatty alcohols, fatty esters, tocopherols, and phospholipids.
• these additives can be selected to tune the dissolution rate of the crosslinked compound after crosslinking as desired.
• the therapeutic agent can be provided in liquid form or dissolved in a suitable solvent.
• therapeutic agent is provided as a particulate and mixed in a suitable carrier for application as a fluid.
• the expandable member is fabricated from polymeric material such as compliant, non- compliant or semi-compliant polymeric material or polymeric blends (e.g., a mixture of polymers).
• the polymeric material is compliant such as but not limited to a polyamide/polyether block copolymer (commonly referred to as PEBA or polyether-block- amide).
• PEBA polyamide/polyether block copolymer
• polyamide and polyether segments of the block copolymers can be linked through amide or ester linkages.
• the polyamide block can be selected from various aliphatic or aromatic polyamides known in the art.
• the polyamide is aliphatic. Some non-limiting examples include nylon 12, nylon 11, nylon 9, nylon 6, nylon 6/12, nylon 6/11, nylon 6/9, and nylon 6/6. In some embodiments, the polyamide is nylon 12.
• the polyether block can be selected from various polyethers known in the art. Some non-limiting examples of polyether segments include poly(tetramethylene ether), tetramethylene ether, polyethylene glycol, polypropylene glycol, poly(pentamethylene ether) and
• PEBA material can also be utilized such as for example, PEBAX® materials supplied by Arkema (France).
• PEBAX® materials supplied by Arkema (France).
• Various techniques for forming a balloon from polyamide/polyether block copolymer is known in the art. One such example is disclosed in U.S. Patent No. 6,406,457 to Wang, the disclosure of which is incorporated by reference.
• the balloon material is formed from polyamides.
• the polyamide has substantial tensile strength, be resistant to pin-holing even after folding and unfolding, and be generally scratch resistant, such as those disclosed in U.S. Patent No. 6,500,148 to Pinchuk, the disclosure of which is incorporated herein by reference.
• polyamide materials suitable for the balloon include nylon 12, nylon 11, nylon 9, nylon 69 and nylon 66.
• the polyamide is nylon 12.
• Other suitable materials for constructing non-compliant balloons are polyesters such as poly(ethylene terephthalate) (PET), Hytrel thermoplastic polyester, and polyethylene.
• the balloon is formed of a polyurethane material, such as TECOTHANE® (Thermedics).
• TECOTHANE® is a thermoplastic, aromatic, polyether polyurethane synthesized from methylene disocyanate (MDI), polytetramethylene ether glycol (PTMEG) and 1,4 butanediol chain extender.
• MDI methylene disocyanate
• PTMEG polytetramethylene ether glycol
• 1,4 butanediol chain extender 1,4 butanediol chain extender.
• TECOTHANE® grade 1065D is suitable, and has a Shore durometer of 65D, an elongation at break of about 300%, and a high tensile strength at yield of about 10,000 psi.
• other suitable grades can be used, including
• TECOTHANE® 1075D having a Shore D hardness of 75.
• suitable compliant polymeric materials include ENGAGE® (DuPont Dow Elastomers (an ethylene alpha-olefin polymer) and EXACT® (Exxon Chemical), both of which are thermoplastic polymers.
• suitable compliant materials include, but are not limited to, elastomeric silicones, latexes, and urethanes.
• the compliant material can be cross linked or uncrosslinked, depending upon the balloon material and characteristics required for a particular application. Certain polyurethane balloon materials are not crosslinked. However, other suitable materials, such as the polyolefinic polymers ENGAGE® and EXACT®, can be crosslinked.
• the final inflated balloon size can be controlled. Conventional crosslinking techniques can be used including thermal treatment and E-beam exposure. After crosslinking, initial pressurization, inflation, and preshrinking, the balloon will thereafter expand in a controlled manner to a reproducible diameter in response to a given inflation pressure, and thereby avoid overexpanding the stent (if used in a stent delivery system) to an undesirably large diameter.
• the balloon is formed from a low tensile set polymer such as a silicone-polyurethane copolymer.
• the silicone-polyurethane is an ether urethane and more specifically an aliphatic ether urethane such as PURSIL AL 575A and PURSIL ALIO, (Polymer Technology Group), and ELAST-EON 3-70A, (Elastomedics), which are silicone polyether urethane copolymers, and more specifically, aliphatic ether urethane cosiloxanes.
• the low tensile set polymer is a diene polymer.
• diene polymers can be used such as but not limited to an isoprene such as an AB and ABA poly(styrene-block-isoprene), a neoprene, an AB and ABA poly(styrene-block- butadiene) such as styrene butadiene styrene (SBS) and styrene butadiene rubber (SBR), and 1,4- polybutadiene.
• the diene polymer is an isoprene including isoprene copolymers and isoprene block copolymers such as poly(styrene-block-isoprene).
• a suitable isoprene is a styrene-isoprene- styrene block copolymer, such as Kraton 1161K available from Kraton, Inc.
• a variety of suitable isoprenes can be used including HT 200 available from Apex Medical, Kraton R 310 available from Kraton, and isoprene (i.e., 2-methyl-l,3- butadiene) available from Dupont Elastomers.
• Neoprene grades useful in the disclosed subject matter include HT 501 available from Apex Medical, and neoprene (i.e., polychloroprene) available from Dupont Elastomers, including Neoprene G, W, T and A types available from Dupont Elastomers.
• HT 501 available from Apex Medical
• neoprene i.e., polychloroprene
• Dupont Elastomers including Neoprene G, W, T and A types available from Dupont Elastomers.
• the outer surface of the balloon is modified.
• the balloon surface can include a textured surface, roughened surface, voids, spines, channels, dimples, pores, or microcapsules or a combination thereof, as will be described below.
• the balloon is formed of a porous elastomeric material having at least one void formed in the wall of the balloon surface.
• the entire cross section of the balloon can contain a plurality of voids.
• the plurality of void can be distributed along select lengths of the balloon outer surface.
• the plurality of voids can be distributed only along the working section of the balloon.
• the voids define an open space within the outer surface of the balloon.
• the crosslinkable compound and/or therapeutic agent is dispersed within the space defined by the plurality of voids across the cross section of the balloon outer surface.
• the therapeutic agent, crosslinkable compound, or crosslinking source is released or is expelled from the pores upon inflation of the balloon.
• the durometer of the polymeric material of the balloon surface and in particular the depression of the void is sufficiently flexible to allow for expulsion of the therapeutic agent and/or coating contained within the plurality of voids upon inflation of the balloon.
• the expelled coating with therapeutic agent is released into the vessel lumen or into the tissue surrounding and contacting the inflated balloon.
• the balloon can include two concentric balloons in a nesting configuration.
• the crosslinkable compound and/or therapeutic agent is disposed between the two concentric balloons.
• a crosslinking catalyst is disposed between the two concentric balloons.
• the space between the two concentric balloons; one being an interior balloon and the other being an exterior balloon acts as a reservoir.
• the protrusions can include apertures for expulsion of the crosslinking source, such as a solvent or crosslinking agent as disclosed above, or expulsion of the crosslinkable compound and/or therapeutic agent upon inflation of the interior and exterior concentric balloons.
• the balloon can include longitudinal protrusions configured to form ridges on the balloon surface.
• the ridges can be formed of filaments spaced equidistantly apart around the circumference of the balloon. However, a larger or smaller number of ridges can alternatively be used.
• the longitudinal ridges can be fully or partially enveloped by the polymeric material of the balloon.
• the balloon can include microcapsules on its outer surface.
• the microcapsules are configured to encompass the crosslinking source and/or the crosslinkable compound and/or therapeutic agent.
• the microcapsules located on the surface of the balloon contact the tissue of the arterial wall.
• the microcapsules can be formed in the wall of the balloon surface.
• the crosslinkable compound and/or therapeutic agent can be released from the microcapsules by fracturing of the microcapsules and/or diffusion from the microcapsule into the arterial wall.
• the microcapsules can be fabricated in accordance with the methods disclosed in U.S. Patent No. 5,1023,402 to Dror or U.S. Patent No. 6,129,705 to Grantz and the patents referenced therein, each of which is incorporated herein by reference in its entirety.
• the surface of the expandable member or balloon is modified to promote deposition of the crosslinking source and/or the crosslinkable compound and/or the therapeutic agent on the balloon surface and within the balloon wall membrane.
• Suitable techniques for such modification are disclosed, for example, in U.S. Patent Publication No. 2008/0113081to

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