Drug-delivery endovascular stent

(Field of invention) The present invention relates to a polymeric composition composed of a polymeric substrate comprising a 40-O-hydroxyalkyl substituted rapamycin derivative, wherein the alkyl has 7-11 carbon atoms.

(Background of invention) Rapamycin is a macrocyclic triene compound first extracted from a strain of Streptomyces hygroscopicus isolated from Easter Island soil samples (Vezina et al., J. Antibiot. 28: 721 (1975); US Pat. No. 3,929,992; No. 3,993,749). Rapamycin has the following formula I:

<chemistry num="2"><img file="JP5113667B2_D0001.tif" /></chemistry>It has the structure shown in. Originally described for use as an antifungal agent (US Pat. No. 3,929,992), followed by use in the treatment of cancer and tumors (US Pat. No. 4,885,171), use for the prevention of experimental immunopathology (experimental). Allergic Encephalitis and Adjuvant Arthritis; Martel, R., Can.J.Physio., 55:48 (1977), Inhibition of Transplant Rejection (US Pat. No. 5,100,899) and Inhibition of Smooth Muscle Cell Proliferation (Morris) , R., J. Heart Lung Transplant, 11 (pt.2) (1992)) have been found to be effective agents for other conditions and disorders.

However, the use of compounds as pharmaceutical drugs has been limited by their very low and variable bioavailability and their toxicity. Also, rapamycin is very slightly soluble in water (20 micrograms per milliliter) and is difficult to formulate into a stable composition suitable for in vivo delivery. To solve these problems, compound prodrugs and derivatives have been synthesized. Water-soluble prodrugs prepared by derivatizing rapamycin positions 31 and 40 of the rapamycin structure to form prodrugs of glycinate, propionate and pyrrolidinobutyrate are described (US Pat. No. 4,650,803). Numerous derivatives of rapamycin described in the art include: monoacyls, derivatives and diacyl derivatives (US Pat. No. 4,316,885), acetal derivatives (US Pat. No. 5,151,413), silyl ethers (US Pat. No. 5,120,842). (US Pat. No. 5,362,718) and derivatives of alkyl, aryl, alkenyl, and alkynyl (US Pat. No. 5,665,772; US Pat. No. 5,258,389; US Pat. No. 6,384,046; WO 97/35575).

<p> (Gist of the invention) In one aspect, the invention comprises a polymeric composition for use in the delivery of macrocyclic triene compounds to an internal target site of a subject. The compositions consist of (i) 20-70% by weight polymer substrate and (ii) 30-80% by weight:</p><p><chemistry num="3"><img file="JP5113667B2_D0002.tif" /></chemistry>Containing a macrocyclic triene compound having the structure of Where R is CH₂-X-OH, where X is a straight or branched chain alkyl containing 6-10 carbon atoms. When placed on cells at the target site, the composition takes up substantially more of the compound in the target site cells than is achieved with the same polymeric substrate containing rapamycin or everolimus macrocyclic triene compounds. Effective in achieving levels.</p><p> In one embodiment, the composition is for use in the treatment of solid tumors, inflammations or wounds at the target site and consists of a suspension of injectable particles that can be localized by injection into the target site. Will be done.</p><p> In another embodiment, the polymer substrate in the composition is formed from a bioerodible polymer.</p><p> In yet another embodiment, the composition is intended for use in the treatment of solid tumors, inflammations or wounds at the target site and takes the form of patches formed from polymeric substrates and compounds. The drug-containing patch is placed on the surface of a tissue structure (eg, the outer or inner surface of an organ or tumor or the outer or inner surface of a blood vessel).</p><p> The composition also finds use in the treatment of inflamed tissue or wounds, and the polymeric substrate takes the form of an ointment for application to tissue in need of treatment.</p><p> The composition has also been found to be used in inhibiting restenosis at the site of injury to the vessel wall, and the composition comprises a coating that is conserved on the vessel wall contact portion of an expandable vascular stent.</p><p> In another embodiment, the composition is intended for use in the delivery of macrocyclic triene compounds to cells on the mucosal surface. The polymeric substrate in the composition has a mucosal adherent surface coating suitable for placement on mucosal tissue.</p><p> In any or all of these uses, the compound is, in one embodiment, a structure of form in which R is CH2-X-OH and X is a linear alkyl group having 6-10 carbon atoms. Has. In another embodiment, R is CH₂-X-OH, and X is a linear alkyl group containing 6 carbon atoms.</p><p> In another embodiment, the polymer substrate is composed of a biodegradable polymer. Examples of biodegradable polymers include polylactic acid, polyglycolic acid and mixtures thereof. Suitable polylactic acids include poly (l-lactide), poly (d-lactide) and poly (dl-lactide).</p><p> In another embodiment, the macrocyclic triene compound is present at an initial concentration of 35-80% by weight by weight of the total composition.</p><p> These as well as other objects and properties of the invention will become more apparent when the following detailed description of the invention is read in combination with the accompanying drawings.</p><p> (Detailed description of the invention) (I. Definition) As used herein, "rapamycin" means:</p><p><chemistry num="4"><img file="JP5113667B2_D0003.tif" /></chemistry>A compound having the structure of is intended. This compound is known in the art as "sirolimus".</p><p> The "40-O-hydroxyalkyl-substituted rapamycin" compound means a compound in which the hydroxyl group is modified to contain hydroxyalkyl at carbon number 40 in the rapamycin compound. For example, (CH₂)₇Modifications at the 40-O position to replace the hydrogen in the hydroxyl group at OH are referred to as 40-O-hydroxyheptyl rapamycin.</p><p> What is "Everolimus"?</p><p><chemistry num="5"><img file="JP5113667B2_D0004.tif" /></chemistry>A compound of the structure is intended, where R is CH₂CH₂It is OH (hydroxyethyl).</p><p> An "efficacious amount" or "effective amount" is intended to be a dosage sufficient to provide treatment for the disorder or disease condition to be treated. This will vary depending on the patient, disease and treatment performed, but will be readily determined using specific clinical markers for the disorder or disease for the purpose. For example, after vascular transplantation and injury due to over-dilation of a stent using a balloon catheter, cross-sectional area measurement of the amount of new tissue growth inside the stent provides a clinical marker for restenosis. After application of active drug dosage at the tumor site, reduction or stabilization of tumor volume provides clinical markers for tumor treatment. Clinical markers associated with organ transplantation or vascular graft surgery are monitoring organ function and the continued patency of allogeneic transplantation. For cutaneous wounds, the clinical marker is to observe inflammatory marker changes in redness, granulomatous formation or fibrosis. For benign prostatic hyperplasia, a clinical marker is to monitor any reduction in recurrence of ureteral obstructions.</p><p> (II. Polymer composition) The present invention relates to a polymeric composition comprising a 40-O-hydroxyalkyl (C7-C11) substituted rapamycin compound. As mentioned above, many rapamycin and its derivatives have low bioavailability, limiting their usefulness as drugs. In the present invention, certain 40-O-hydroxyalkyl derivatives of rapamycin have been found to provide improved bioavailability when formulated into polya-structures and when contacted with tissue for treatment. It has been issued. Rapamycin compounds for use in polymer compositions are compounds with the 40-O position modified as follows:</p><p><chemistry num="6"><img file="JP5113667B2_D0005.tif" /></chemistry>Where R is CH₂-X-OH, where X is a straight or branched alkyl group containing 6-10 carbon atoms. In one embodiment, X is a straight chain or branched chain alkyl with 6-10 carbon atoms, or in another embodiment a straight chain or branched chain with 7-11 carbon atoms. It is an alkyl chain. In a preferred embodiment, X is a linear alkyl having 6 carbon atoms. R is CH₂Compounds that are X-OH and are alkyl Xs of 6, 7, 8, 9 or 10 carbons are herein 40-O-hydroxyheptyl, 40-O-hydroxyoctyl and 40-, respectively. They are called O-hydroxynonyl, 40-O-hydroxydecyl and 40-O-hydroxyundecyl.</p><p> FIG. 1 is a semi-logarithmic plot showing the relative hydrophobicity (Rm value) of some drugs. The Rm value is used as a measure of hydrophobicity (Biagi G. et al., J. Medical Chem., 18 (9): 873 (1975); Ichihaski, T. et al., Pharm. Res., 11 (4) :. 508 (1994)). Rm values were determined using the common method of Biagi et al. Using reverse phase thin layer chromatography techniques. By this method, the test compound can be partitioned between the polar mobile phase and the non-polar stationary phase. Rm can be determined by measuring the relative mobility of each compound. Reversed phase chromatography, HPTLC-RP18F unibond octadecyl modified silica thin layer chromatography plate (Alltech) It was carried out using 63077). The polar mobile phase was composed of various concentrations of water (v / v) containing acetone. Visualized by UV quenching at 254 nm. The results for the following compounds are shown in Figure 1: 40-O-hydroxyheptyl rapamycin (black circle), everolimus (40-O-hydroxyethyl rapamycin; white square) rapamycin (black rhombus), paclitaxel (white triangle). And dexamethasone (black square). Table 1 shows the y-blocking values of each compound.</p><p><tables num="1"><img file="JP5113667B2_D0006.tif" /></tables> This y-blocking value is log, so 40-O-hydroxyheptyl rapamycin is about 7 times more hydrophobic than 40-O-hydroxyethyl rapamycin (Eberocimus), and this 40-O-hydroxyethyl rapamycin is rapamycin. More than about 1 times more hydrophobic. Based on this data, the relative water solubility of these compounds is in the following order: Dexamethasone &gt;&gt; paclitaxel &gt;&gt;&gt; rapamycin&gt; everolimus &gt;&gt;&gt;&gt;&gt; 40-O-hydroxyheptyl rapamycin.</p><p> With respect to 40-O-hydroxyheptyl rapamycin, rapamycin and everolimus are more similar to each other in their lytic properties, and thus their bioavailability properties, than either rapamycin or everolimus is similar to 40-O-hydroxyheptyl rapamycin. ing. The poor water solubility of 40-O-hydroxyheptyl rapamycin is generally considered an undesirable candidate for use as a drug. This is because such poorly soluble compounds typically have poor bioavailability and are difficult to formulate for administration. However, as shown below, this compound and a 40-O-hydroxyalkyl derivative of rapamycin may be desired for administration for bioavailability at the treatment site.</p><p> Thus, in one aspect, the invention provides a polymeric composition for use in delivering a 40-O-hydroxyalkyl (C7-C11) substituted rapamycin compound into a patient. Typically, this polymer composition is composed of a selected polymer between 20% and 70% by weight and a 40-O-hydroxyalkyl substituted rapamycin compound between 30-80% by weight. Alternatively, the composition may comprise a selected polymer between 30-70% by weight and a 40-O-hydroxyalkyl-substituted rapamycin compound between 30-70% by weight.</p><p> As mentioned above, a wide range of polymers and formulations are intended and some specific examples are discussed in more detail below. In general, the polymeric composition acts as a series of drug reservoirs that contain the compound and release the compound after deposition at the target site.</p><p> (Polymer particles) An exemplary polymer composition is a formulation of polymer particles suitable for placement in vivo by injection or by deposition using a device such as a catheter. The polymer particles can be microporous, macroporous or non-porous and can be formed from a polymer capable of retaining a poorly water-soluble 40-O-hydroxyrapamycin compound.</p><p> Porous polymer particles have interconnected pores that open toward the particle surface for communication between the outer and inner pore spaces of the particles. Exemplary particles for the formation of such macroporous reservoirs are described, for example, in US Pat. No. 5,135,740 (incorporated herein by reference). Briefly, porous particles are formed, for example, by suspension polymerization in a liquid-liquid system. Generally, a solution containing a monomer and a polymerization catalyst (which is immiscible with water) is formed. An inert solvent that is miscible with this solution but is immiscible with water is included in this solution. The solution is then suspended in an aqueous solution, which generally contains additives that promote suspension or emulsification (eg, surfactants and dispersants). Once a suspension containing individual droplets of the desired size has been established, polymerization is typically carried out by activating these reactants at elevated temperatures or by irradiation. Once the polymerization is complete, the resulting solid particles are recovered from this suspension. These particles are a solid, spherical, porous structure, a polymer that is formed around an inert liquid, thereby forming a pore network. The porogen, an inert solvent that acts as a pore-forming agent, occupies the pores of the particles. Porogen is substantially removed.</p><p> Macroporous particles can also be prepared by evaporating the solvent from either a biodegradable polymer or a non-degradable polymer. For solvent evaporation processes, the desired polymer is dissolved in an organic solvent, then the solution is poured onto a layer of sodium chloride crystals of the desired particle size (Mooney, et al., J. Biomed. Mater. Res. 37). : 413-420, (1997)). This solvent is generally removed by evaporation, and the resulting solid polymer is soaked in water to remove sodium chloride, resulting in a porous polymer reservoir. Alternatively, the sodium chloride crystals can be dispersed in the polymer solution by stirring to obtain a uniform dispersion of the sodium chloride crystals. The dispersion is then extruded into a non-solvent for the polymer with stirring, and droplets of the polymer settle around the sodium chloride crystals. The solid polymer particles are recovered by filtration or centrifugation and then immersed in water to remove sodium chloride, resulting in a porous polymer reservoir. It is understood that alternatives to sodium chloride include any non-toxic water-soluble salt or low molecular weight water-soluble polymer, which can be removed to produce the desired pore space.</p><p> These porous particles can be filled with one or more drugs by including the compound in the polymer during particle formation or by filling the particles after particle formation. Post-particle loading is, for example, dissolving the drug compound in a solvent, which acts to solvate the drug, but is non-solvent to the polymer, and the particles and It can be carried out by mixing the drug solution by stirring. This drug solution is absorbed by the particles, producing a free-flowing powder. These particles can then be treated for solvent removal, if desired.</p><p> Another exemplary polymer particle composition is non-porous particles (eg, microcapsules and microparticles with compounds contained or dispersed therein). Both microcapsules and microparticles are well known in the drug and drug delivery industry (eg Baker, RW, CONTROLLED RELEASE OF BIOLOGICALLY ACTIVE AGENTS, John Wiley &amp; Sons, NY, 1987; Ranade V. and Hollinger, M., DRUG. See DELIVERY SYSTEMS, CRC Press, 1996). The microcapsule typically refers to a reservoir of active agent surrounded by a polymer shell membrane. The fine particles typically refer to a monolithic system in which a therapeutic agent is dispersed throughout the particles. However, there are many formulations included between these two definitions (eg, agglomerates of microcapsules), and such formulations are also suitable for use herein.</p><p> Microcapsules and microparticles can be prepared from biodegradable or non-biodegradable polymers. Microcapsules are easily formed by a number of methods, including concentration, interfacial polymerization, solvent evaporation, and physical encapsulation (Baker, RW, CONTROLLED RELEASE OF BIOLOGICALLY ACTIVE AGENTS, John Wiley &amp; Sons, NY). , 1987). Microcapsules are prepared by a number of techniques known in the art, and one simple method is simply to grind the polymer film containing the dispersed therapeutic agent to the appropriate size. Spray drying of particulate therapeutics from polymer solutions is another approach. Specific procedures for encapsulation of biologically active agents are disclosed in US Pat. No. 4,675,189 and US Patent Application 20010033868, which are incorporated herein by reference.</p><p> Suitable polymers for particle formation are many and diverse: a common selection criterion is a polymer capable of delivering a 40-O-hydroxyalkyl-substituted rapamycin compound. Exemplary polymers include poly (d, l-lactic acid), poly (l-lactic acid), poly (d-lactic acid), methacrylate polymers (eg, polybutyl methacrylate), ethylene vinyl alcohol (EVOH), ε- Caprolactone, ethyl vinyl hydroxylated acetate (EVA), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyesteramide, and copolymers and mixtures thereof include, but are not limited to. All of these polymers have a safety history and low inflammatory use in systemic circulation. Typically, a polymer between 20% and 70% by weight is combined with a 40-O-hydroxyalkyl substituted rapamycin compound between 30% and 80% by weight to form a polymer composition.</p><p> The size of the particles, whether pore-like or non-porous, can vary very widely, from about 0.1 micron to about 100 microns in diameter, preferably from about 0.5 micron to about 40 microns. These particles can be administered as neat particles or formulated as gels, pastes, ointments, salves or viscous liquids for application at the target site.</p><p> As exemplified by the polymeric particles, the polymeric compositions of the present invention are compositions that can be applied or placed on the tissue target site for contact between the polymer composition and the tissue at the target site. Those skilled in the art will appreciate that these polymeric particles are merely an example of a composition that achieves contact with a target tissue. Polymers capable of delivering large amounts of hydrophobic compounds can be formulated in films, patches, pastes, ointments or gels, all of which can be placed or applied to the target site. For example, a simple polymer patch prepared from a polymer loaded with a 40-O-hydroxyalkyl substituted rapamycin compound can be placed on the tissue surface in need of treatment. Such tissue surfaces can be blood vessels, organs, tumors, or body surfaces that are damaged or have wounds.</p><p> (Mucosal adhesive polymer composition) In another embodiment, the polymeric composition consists of a polymeric substrate with mucosal adhesive properties due to its placement adjacent to the mucosal tissue. Mucosal tissues in the body include the blind tract of the eye, the buccal cavity, the nose, the rectum, the vagina, the periodontal pocket, the intestine and the colon. The mucosal adhesive delivery system exhibits adhesion to mucosal tissue due to the administration of the compounds contained within the mucosal adhesive polymer.</p><p> Various polymer compositions are used in mucosal delivery formulations. Of particular interest for use with 40-O-hydroxyalkyl substituted rapamycin compounds are mucosal adhesives that have a combination of hydrophilic and hydrophobic properties. An exemplary adhesive in a sticky hydrocarbon polymer for adhesion to the oral mucosa, which is a combination of pectin, gelatin, and sodium carboxymethyl cellulose. Other mucosal adhesives with hydrophilic and hydrophobic predominance include, for example, poly (methyl vinyl ether) dispersed in an ointment base (eg, mineral oil containing dispersed polyethylene (US Pat. No. 4,948,580)). / Maleic anhydride) and a copolymer of gelatin can be mentioned. Another hydrophilic / hydrophobic system is described in US Pat. No. 5,413,792, which discloses a paste-like preparation of a polyorganic siloxane and a water-soluble polymeric material.</p><p> In the present invention, a polymer composition comprising a mucosal adhesive polymer base and a 40-O-hydroxyalkyl substituted rapamycin compound is intended. This mucosal adhesive polymer composition is formulated in a delivery system suitable for placement adjacent to the mucosal surface. The compound is eluted from the polymer composition into the tissue when placed adjacent to the mucosal tissue. This delivery system may take the form of a patch to be placed on the surface of the tissue to be treated. This tissue can be an organ, vessel, tumor, or any surface of the body that requires treatment.</p><p> (Intravascular stent) Another exemplary polymer composition for use in the present invention is a polymer coating carried on an expandable vascular stent. Figures 2 and 3 are schematic representations of an intravascular stent coated with a polymer composition carrying a 40-O-substituted rapamycin compound. In these figures, the stent 20 is shown in the contracted state (FIG. 2) and the expanded state (FIG. 3) of the stent. The stent comprises a structural member or body 22, and an outer coating for retaining and releasing the compound, as further described below with reference to FIGS. 3 and 4.</p><p> In the embodiments shown in FIGS. 2 and 3, the stent body is formed from a plurality of connected tubular members by filaments (eg, members 24, 26). Each member has an expandable zigzag, serrated, or sinusoidal structure. This member is connected by an axial connection (eg, connection 28, 30) that connects the vertices and valley bottoms of adjacent members. As can be understood, this configuration allows the stent to expand from the contracted state shown in FIG. 2 to the expanded state shown in FIG. 3 with little or no change in the length of the stent. .. At the same time, the relatively rare connection between the apex and valley bottom of adjacent tubular members allows the stent to adapt to bending. This feature can be particularly important when the stent is delivered to the vascular site in its contracted state, either in or on the catheter. The stent has a typical contracted diameter between 0.5 and 2 mm, more preferably 0.71 and 1.65 mm (FIG. 2), and a length between 5 and 100 mm. In the dilated state as shown in FIG. 3, the diameter of the stent is at least twice, 8-9 times, the diameter of the stent in its contracted state. Thus, a stent with a contraction diameter of 0.7-1.5 mm can be radially expanded to a selected dilated state between 2-8 mm and above.</p><p> This common stent of connected expandable tubular members-a stent with a body structure is described, for example, by PCT Publication No. WO As described in 99/07308, it is known and is owned by the same person as this application and is hereby incorporated by way of reference. Further examples are described in U.S. Pat. Nos. 6,190,406, 6,042,606, 5,860,999, 6,129,755, or 5,902,317 (these patents are incorporated herein by reference). To. Alternatively, the structural member of the stent may have a continuous spiral ribbon configuration (ie, the stent body is formed from a single continuous ribbon-like coil). The basic requirements of the stent body are that the stent body is expandable as it is deployed at the site of vascular injury, and that the stent body is the vascular wall (ie, tissue) that lines the vascular target site. It is suitable for receiving the drug-containing coating on the outer surface of the stent body in order to deliver the drug contained in the drug-containing coating to the inner layer, outer membrane layer and endothelial layer). Preferably, the body also has a lattice or open structure, allowing the endothelial cell wall to propagate "through" the stent from the outside to the inside.</p><p> The stent filaments are distributed in a polymer matrix and in this matrix for a period of at least several weeks (typically 4-8 weeks, and optionally 2-3 months, or longer). It is coated with a drug release coating consisting of a 40-O-hydroxyalkyl substituted rapamycin compound released from this stent.</p><p> FIG. 4 is an enlarged cross-sectional view, complete on all sides, i.e., the top (filament side forming the outer surface of the stent body) bottom (filament side forming the inner surface of the stent) and the opposing filament side. 2 shows a stent filament 24 having a coating 32 covering the filament. As further discussed below, coatings typically have a thickness of 3-30 microns, which depends on the nature of the polymer matrix material forming the coating and the relative amount of polymer matrix and active compound. .. Ideally, the coating should be made as thin as possible (eg, 15 microns or less) to minimize the stent profile in the vessel at the site of injury.</p><p> The coating should also be relatively uniform in thickness across the upper (outer) surface to facilitate even distribution of the drug released at the target site. Methods for producing a relatively uniform coating thickness on the stent filament are discussed below.</p><p> The polymer underlayer 34 placed between the stent filament and the coating is also shown in FIG. The purpose of the underlayer is to help adhere the coating to the stent body filament, i.e. to help stabilize the coating on the filament. This feature is of particular value if the coating is formed from a polymeric substrate containing a high percentage of compounds (eg, 35-80 weight percent compounds), as seen below. One exemplary underlayer polymer is parylene used in combination with a polymer substrate formed from bioerodible (poly-dl-lactide). Other suitable polymer underlayers are ethylene vinyl alcohol (EVOH), paryLAST^TM, Parylene, Silicon, TEFLON®^TM, And other fluororesins, which can be deposited on the surface of the metal stent by plasma coating or other coating, or deposition process. This underlayer has a typical thickness of 1-5 microns.</p><p> The polymer forming the substrate can be any biocompatible polymer material, from which the trapped compound can be released by diffusion and / or by corrosion of the polymer matrix. Two well-known non-corrosive polymers for coating substrates are polymethylmethacrylate and ethylene-vinyl alcohol. Methods for preparing these polymers in suitable forms for application to the stent body are described, for example, in US2001 / 0027340A1 and WO00 / 145763, which are incorporated herein by reference. Generally, the limit of drug addition to the polymer is in the range of about 20-40 weight percent.</p><p> Bio-erosive polymers, especially poly-dl-lactide polymers, are also suitable for coating substrate materials. In one general embodiment of the invention, the coating is a bioerosible poly-dl-lactide polymer substrate, i.e. a poly-dl-lactic acid polymer, which is dispersed in the polymer substrate. It can contain up to 80% of the dry weight of the active compound. More generally, the coating comprises 35-80% of the dry weight of the active compound and 20-65% of the dry weight of the polymer. An exemplary coating comprises 25-50% dry weight polymer matrix and 50-75% weight active compound. This polymer is formulated with an active compound for deposition on a stent filament, as detailed below.</p><p> One preferred coating with a coating thickness between 3 and 15 microns is formed from 25 to 50 weight percent poly-dl-lactide polymer substrate and 50 to 75 weight percent macrocyclic triene immunosuppressive compound. The underlayer is formed from parylene and has a thickness between 1 and 5 microns. This embodiment typically comprises an amount of drug equal to about 15 micrograms of drug per stent length (mm).</p><p> In an exemplary embodiment, the polymer coating is formed from 15-35 weight percent corrosive or non-corrosive polymer base material and 65-85 weight percent 40-O-hydroxyalkyl substituted rapamycin compounds. To. The polymer coating thickness is preferably 10-30 microns and the stent may include a 1-5 micron polymer underlayer (eg, parylene underlayer). This embodiment typically comprises an amount of compound equivalent to about 15 micrograms of drug per stent length (mm).</p><p> The coating may further comprise a second bioactive agent that is effective for treating the associated disease or condition, or for treating any predicted secondary condition that may occur. For example, when 40-O-hydroxyalkyl-substituted rapamycin is administered for the treatment of restenosis, blood-related events that can be stimulated by the original vascular injury, the presence of a stent (eg, coagulation). A second compound may be included to minimize or improve vascular healing at the site of injury. An exemplary second agent is an antiplatelet agent in soluble crystalline form, a fibrin-dissolving agent, or a thrombus-disintegrating agent, or a NO donor that stimulates endothelial cell healing and controls smooth muscle cell proliferation. Can be mentioned. Exemplary antiplatelet agents, fibrin-dissolving agents, or thrombolytic agents are heparin, aspirin, hirudin, ticlopidine, eptifibatide, urokinase, strepdokinase, tissue plasminogen activator (TPA), or It is a mixture of them. If the 40-O-hydroxyalkyl substituted rapamycin is intended for use as an antitumor agent, it may include a second agent commonly used for chemotherapy for neoplastic diseases. Exemplary second chemotherapeutic agents include paclitaxel, platinum compounds, cytarabine, 5-fluorouracil, teniposide, etoposide, methotrexate, doxorubicin and the like. The amount of the second agent contained in the stent coating is determined by the length of time the agent needs to provide a therapeutic effect. The second agent may be included in the coating formulation applied to the stent body filament according to known methods.</p><p> (Bio-erosive stent) In another general embodiment, both the stent body and the polymer coating are formed of bioerosive polymer, allowing the stent to be completely reabsorbed over time. The stent is preferably an expandable coiled stent with a helical ribbon filament forming the stent body (not shown). Self-expandable coil stents are described in US Pat. No. 4,990,155 for intravascular implantation and are incorporated herein by reference.</p><p> A coiled stent is formed using a preform with the final dilation diameter of the preform, which is designed to be slightly larger than the size of the lumen of the blood vessel to be treated by this coil. (3.5 mm OD ± 1 mm is common for coronary arteries). More generally, the stent can be formed as an expanded form by molding and, when attached to the tip of the catheter, either twist around the long axis of the stent for delivery to the blood vessels or radial to the stent. It is made into a contracted state by applying a force to the. The stent preferably has a total thickness between about 100 microns and 1000 microns and a total length between 0.4 cm and 10 cm. In fact, an important advantage of this type of bioerodible stent is that relatively long stents (eg, lengths greater than 3 cm) can be easily delivered and placed at the site of vascular injury.</p><p> Methods for forming balloon expandable stents formed of woven bioerodible polymer filaments (eg, poly-l-lactide) have been reported (US Pat. No. 6,080,177). The device version is also adapted to release the drug (US Pat. No. 5,733,327).</p><p> The preferred polymeric material for stenting is poly-l-lactide or poly-dl-lactide (US 6,080,177). As mentioned above, the stent body and coating can be integrally formed as a single expandable fibrous stent with an anti-restenotic compound contained on one side. Alternatively, a bioerodible coating may be applied to the preformed bioerodible body, as detailed in the section below. In the latter case, the stent body can be formed from one type of bioerosable polymer (eg, poly-l-lactide polymer), and the coating is a second polymer (eg, poly-dl-lactide polymer). ) Can be formed from. When applied to a preformed stent, the coating may have substantially the same compositional and thickness characteristics as described above.</p><p> FIG. 5 shows a cross-sectional view of a filament (eg, a spiral ribbon) in just the type of bioerodible stent with a separately formed body and coating. This figure shows an internal bio-erosive stent filament 36 coated on all sides with a bio-erosive coating 38. The illustrated coating is formed of poly-dl-lactide and contains between 20-40% by weight of 40-O-substituted rapamycin compounds and 60-80% by weight of a polymeric substrate. In another general embodiment, the coating comprises 45-75% by weight of the compound and 25-55% by weight of the polymer matrix.</p><p> Bioerosive stents, either in combination with prior dilation of the vessel with an angioplasty balloon in the presence of large occlusion, or as a prophylactic transplant into a patient at high risk of developing significant future blockade. It has the unique advantage of being able to treat all vessels with a single device. Since this stent is completely biodegradable, it does not affect the patient's opportunity for later uncomplicated vascular surgery like a "full metal jacket", a string of drug-eluting stents containing a metallic substrate.</p><p> A second agent (eg, an agent as described above) can be incorporated into the coating to be released from the coating for a desired period of time after transplantation. Alternatively, if a second agent is used, it can be incorporated into the stent body filament if the coating applied to the stent body does not cover the inner surface of the stent body. The coating methods described below for metallic filament stent bodies are also suitable for use in covering polymer filament stent bodies.</p><p> (Stent coating method) With reference to the drawings in more detail here, FIGS. 5A and 5B are schematic views of the stent coating process according to the present invention. Polymer solution 40 is made by dissolving the polymer in an affinity solvent. The 40-O-substituted rapamycin compound and, if desired, a second agent are added to this solution as either a suspension or solution using the same solvent or different solvents. The finished mixture is placed in a pressure resistant reservoir 42. Connect the reservoir to the fluid pressurizing pump 44.</p><p> The pressurizing pump can be any pressure source capable of moving the solvent mixture through the solution delivery tube 46 at a programmed rate. The pressurizing pump 44 is under the control of a microcontroller (not shown), as is well known in the field of accurate distribution systems. For example, such microcontrollers can be controlled by a personal computer through an RS-232C communication interface, 4-Axis Dispensing Robot Model Numbers I &amp; J500-R and I &amp; J750-R (available from I &amp; J Fisnar Inc, Fair Lawn, NJ). , Or an exact distribution system (eg, Automove A-400 (available from Asymtek, Carlsbad, Ca)). Suitable software programs for controlling the RS232C interface may include the Fluidmove system (also available from Asymtek Inc, Carlsbad, Ca).</p><p> A solution delivery tube 48 for delivering the solvent mixture to the surface of the stent is glued to the reservoir 42 (eg, at the bottom of this reservoir). The pressurizable reservoir 42 and delivery tube 48 move the solvent delivery tube in small steps (eg, 0.2 mm per step) or continuously along the longitudinal axis of the stent, as indicated by arrow X1. Mounted on a movable support (not shown) that can be allowed. Movable supports for the pressurizable reservoir 42 and delivery tube 46 can also move the tip (distal end) of the delivery tube in small steps to bring it closer to the microfilament surface, or as indicated by arrow Y1. In addition, it can be kept away from the microfilament surface.</p><p> The uncoated stent is gripped by a rotary chuck that is in side surface contact with the inside of the stent at at least one end. Axial rotation of the stent is achieved in small angular steps (eg, 0.5 degrees per step) by bonding the stepper motor to the chuck as is well known in the art, and for coating with the delivery tube, of this stent structure. The top surface can be rearranged. If desired, the stent can be rotated continuously. Accurate placement of low volume fluid delivery devices is well known in the field of XYZ solvent partitioning systems and can be incorporated into the present invention.</p><p> The action of the fluid pressurizing pump, the placement of the fluid delivery tubes on X1 and Y1, and the placement of the stent on R1 can typically be coordinated by a digital controller and computer software program, thereby accurate requirements. An amount of solution is welded to any desired location on the surface of the stent, where the solvent can escape, leaving a cured coating of polymer and reagents on the surface of the stent. Typically, the viscosity of the solvent mixture is adjusted by varying the amount of solvent and can range from 2 centipores to 2000 centipores, typically 300 to 700 centipores. Alternatively, the delivery tube can be held in a fixed position and the stent can be moved along the longitudinal direction in addition to rotational movement to accomplish the coating process.</p><p> XYZ placement tables and movable supports can be purchased from I &amp; J Fisnar. A solution delivery tube of preferred size is preferably a stainless steel hypotube between 18-28 gauge mounted on a suitable fixed connector. Such delivery tubes may be obtained from East Providence, RI's EFD Inc. See the EFD selection guide for specific purpose tips. The preferred tip is reorder number 5118-1 / 4-B ~ 5121-1 / 4-B "Burr-free passivated stainless steel tips with 1/4" length for fast point-to-point employed of particle-filled or thick. materials , reorder number 51150VAL-B Oval stainless steel tips apply thick pastes, sealants, and epoxies in flat ribbon "Deposits", and reorder numbers 5121-TLC-B to 5125-TLC-B "Resists clogging of cyanoacrylates and provides additional deposit control for low viscosity fluids. Crimped and Teflon lined". Disposable pressurized solution reservoirs are also available from EFD stock numbers 1000Y5148 ~ 1000Y5152F. An alternative tip for use with the present invention is a glass microcapillary with an inner diameter (ID) of approximately 0.0005 to 0.002 inches (eg, 0.001 inches), VWR Catalog No. 15401-560 "Microhematocrit Tubes" (length). It is available from 60 mm, inner diameter 0.5 to 0.6 mm).</p><p> The tube is further pulled under a Bunsen burner to achieve the desired ID for accurate application of the polymer / drug / solvent mixture. Stepper motors and programmable microcontrollers for operating XYZ tables are available from Asymtek, Inc. Use of more than one type of fluid distribution tube to work together to form a coating, or have different tips, or solutions of different viscosities or different solutions in the same process to form a coating. The alternative use of one or more mobile solution reservoirs, including the chemical composition according to, is within the scope of the present invention. Chuck and stepper motor systems can be purchased from Edmund Scientific of Barrington, NJ.</p><p> Typically, as described above, the coating is applied directly onto the outer support surface (s) of the stent and is the coating system of the invention described above, as shown in FIGS. 6A and 6B. Depending on the control method applied to, it may or may not cover all or part of the inner surface (s) of the stent. The latter figure shows the application of coating material 52 to the top and side regions of filament 50. Alternatively, the coating or coating mixture can also be applied directly to the inner surface of the stent. The thin delivery tip can penetrate one or more cutoff areas (ie, windows) in the wall of the stent structure, whereby the coating mixture can be applied directly onto the inner surface of the desired area. In this method, different coating materials with different drug components can be applied to the outer and inner side surfaces of the filament. For example, the coating on the outer filament surface may contain a 40-O-substituted rapamycin compound, and the coating on the inner filament surface may contain one of the above secondary reagents or another 40-O-substituted rapamycin compound. Can include. If the stent has a sufficiently large diameter, a thin "L-shaped" delivery tip can be inserted into the stent's open end along the longitudinal axis of the stent for the purpose of applying a coating to the inner surface. ..</p><p> Polymers for use in the present invention include poly (d, l-lactic acid), poly (l-lactic acid), poly (d-lactic acid), ethylene vinyl alcohol (EVOH), ε-caprolactam, ethyl vinyl hydroxylated acetate. (EVA), polyvinyl alcohol (PVA), polyethylene oxide (PEO), and copolymers and mixtures thereof (dissolved in chloroform or acetone, or other suitable solvents), but not limited to these. .. All of these polymers have a history of safe and hypoinflammatory use in systemic circulation.</p><p> Non-polymeric coatings of 40-O-substituted rapamycin compounds that ionically bond to the surface of metal stents can also be used in the present invention.</p><p> It has been discovered that it is possible to coat all of the top, side, and medial surfaces of a stent using the coating system described. By carefully choosing the proper ratio of solvent to polymer, the viscosity of the solution is adjusted and, as shown in Figure 6B, some of the solution moves down the sides of the struts and bottoms before solidifying. Actually reach the surface. By controlling the rest time of the delivery tube near the rim of the stent, the amount of polymer coating the rim or bottom of the stent can be increased or decreased. In the embodiment shown in FIG. 4, a lower layer 34 of pure polymer and solvent can first be applied to the stent surface 24 using the coating system of the present invention and the solvent can evaporate. A second layer 32 made of a polymer containing a bioactive reagent is then applied.</p><p> As mentioned above, the secondary reagent can be incorporated into the polymer mixture. For example, crystalline heparin can be incorporated into the coating. Heparin crystals are refined to a particle size of approximately 1-5 microns and added as a suspension in the polymer solution. Suitable forms of heparin include crystalline forms of heparin (heparin salts (ie, heparin sodium and low molecular weight forms of heparin)) that exhibit biological activity in mammalian hosts when applied according to the processes of the invention. , And their salts). As seen in FIG. 9, when a drug delivery stent is placed within the vessel wall, heparin crystals begin to dissolve near the coated surface of the cured polymer, increasing the porosity of the polymer. As the polymer dissolves slowly, more heparin and bioactive reagents are released in a controlled manner.</p><p> However, with reference to FIG. 9, it should be understood that coating the inner surface of the stent is not always desirable. For example, coating the inner surface of the stent increases the crimped delivery profile of the device and reduces motility in small vessels. Then, after implantation into the vessel, the medial surface is washed directly by the blood flow through the stent, releasing any drug on the medial surface and disappearing into the systemic circulation. To that end, in the embodiments shown in FIGS. 4 and 5, bulk cured polymers and reagents are placed in the outer environment of the stent support and secondarily on its sides. In a preferred embodiment, only a minimal amount of polymer and reagent is applied onto the inner surface of the stent. If desired, it is also possible that at least a portion of the inner surface of the stent is uncoated or exposed.</p><p> In addition, the coatings of FIGS. 4 and 5 can be placed on the stent filament surface in a selective fashion. The depth of the section to be coated may correspond to the volume of bioactive coating available to present to the tissue. It may be advantageous to limit the coating from specific areas (eg, areas that are susceptible to high strain levels during stent deployment).</p><p> A uniform underlayer may first be placed on the stent surface to facilitate adhesion of the bioactive factor-containing coating and / or assist in stabilizing the polymer coating on the stent. The primer coat can be applied by using any of the methods already known in the art or by the precision dispensing system of the present invention. The primer coat can be applied to different polymeric materials (eg, parylene (poly (dichloro-para-xylylene)), or any other substrate that exhibits good adhesion to both the base metal substrate and the coating containing the bioactive factor. It is also within the scope of the present invention to apply using (material). Parylene (poly (dichloro-para-xylylene)) can be deposited by plasma or vapor deposition techniques, as is well known in the art (see US Pat. No. 6,299,604). In one embodiment of the invention, an island or layer of coating containing heparin is formed on the inner surface of the stent, and an antiproliferative coating containing the drug of the invention as described above is applied to the outer surface of the stent. It is formed.</p><p> If it is desirable to form a coating with a high drug / polymer substrate ratio, for example if the drug constitutes 40-80% by weight of the coating on the metal stent substrate, then an underlayer is formed on the stent filament. It is advantageous to stabilize and firmly adhere the coating to the substrate. The underlayer can be further processed and then the coating material is deposited by swelling in a suitable solvent (eg, acetone, chloroform, xylene, or a mixture thereof). This approach is described in Example 5 for the preparation of stents with a high ratio of everolimus to poly-dl-lactide.</p><p> Here, the parylene underlayer is formed on the stent filament by plasma deposition, which is then swollen in xylene, followed by the final deposition of the coating material. This method contains 50% drug in one case and 75% drug in another in a poly-dl-lactide polymer substrate in a coating having a thickness of only 5-10 microns. It was effective in producing the coating to be used.</p><p> As described above, the production of fully bioerodible stents using the coating system of the present invention is also within the scope of the present invention. This is done by creating a tubular preform in the shape of the stent to be formed using a "C-shaped" spiral channel with an open top, in which the partitioning system can deposit the polymer. , Can be achieved. This preform is open in its outer diameter, so that the polymer is typically preformed using a single pass (but also multiple passes if necessary) of the distribution tube. It can be deposited within, while creating a uniform edge of the stent structure where the polymer is confined by the preform. This preform is soluble in a solvent that does not dissolve the biodegradable stent thus produced. After the polymer has been deposited and the solvent in the polymer solution has evaporated, the assembly can be placed in a solvent that dissolves the preform to release the finished stent structure. A typical material for preforms is sucrose, which can be molded into the desired preform shape using standard injection molding techniques. A typical solvent for preform is water.</p><p> (how to use) The 40-O-hydroxyalkyl substituted rapamycin compound is intended for use in the treatment of any state response to rapamycin or everolimus. This includes any condition associated with wound healing (eg, postoperative procedures including vascular or organ transplant procedures), neoplastic disease, where, for example, the polymer composition is a cancer (eg, solid). It is placed directly at the site of the tumor). Inflammation and infection are also conditions that can be treated with 40-O-hydroxyalkyl substituted rapamycin derivatives. This compound can also be used for vascular treatment methods, especially restenosis. The compounds are formulated on a polymeric substrate for application to internal target sites in the subject, and exemplary polymeric substrate formulations are as described above. Polymer-coated polymer compositions applied on expandable stents are particularly suitable for the treatment of restenosis.</p><p> With respect to the treatment of vascular injury, the risk and / or extent of restenosis in patients with local vascular injury or at risk of vascular occlusion is a polymer composition comprising a 40-O-hydroxyalkyl-substituted rapamycin compound. Can be minimized using objects. Typically, vascular injury occurs during angiography procedures and opens partially occluded vessels (eg, coronary or peripheral vascular arteries). In the angiography procedure, a balloon catheter is placed at the site of occlusion, and the distal balloon is inflated and contracted one or more times to force the occluded vessel to open. This dilation of the vessel, especially with surface trauma to the wall of the vessel where the plaque can dislodge, often results in localized damage to the vessel by cell proliferation and reocclusion that is sufficient to respond over time. .. Not surprisingly, the occurrence or severity of restenosis is often associated with the degree of vascular elongation involved in the angiographic procedure. Restenosis occurs frequently and often with considerable severity (ie, vascular occlusion), especially when hyperextension is greater than or equal to 35%.</p><p> The stent is placed in its contracted state, typically at the distal end of the catheter, either in the catheter lumen or in the contracted state on the distal end balloon. The distal catheter end is then guided to the site of injury or potential occlusion, and, for example, if the stent is self-expanding, by releasing the stent to that site using a trip wire, or a balloon. By expanding the stent on the balloon until the swelling contacts the vessel wall, it is released from the catheter and, in fact, implants the stent at its site into the tissue wall.</p><p> FIG. 7 shows an embodiment of a fully biodegradable stent, along with a delivery catheter suitable for implanting the device into a blood vessel of the cardiovascular system (eg, coronary artery). This figure shows the stent 53 (referred to as the "drug coil") in a partially released position. This stent, which is a type of self-expanding coil, is formed from polylactic acid and contains one or more active biological factors.</p><p> The coil is made using a preform and the final dilation diameter of the preform is determined to be slightly larger than the internal lumen size of the blood vessel treated with this coil. After removing this preform, the drug coil is wound around a coil of smaller radius by twisting both ends in the opposite direction so that the delivery diameter can slide up to about 1/3 of the final dilated diameter at body temperature. Under the sheath, it is compressed along its entire length. The drug coil is thin enough (approximately 25-125 microns) to easily bend to a tighter radius to form a compressed coil at the inner diameter of the sheath. The sheath is slidably placed on the delivery catheter 55 and is suitable for delivering the stent in its compressed state to the target vessel. The sheath 54 has a gripping means 56 at its proximal end, which allows the angioplastist to pull back the sheath if the tip of the delivery catheter is in the proper position within the vessel, and pull the drug coil. Can be completely released.</p><p> The center of the delivery catheter 55 has a lumen about 0.014 inches in diameter into which a guide wire 57 with a flexible tip 58 can be slidably placed. This delivery catheter also has a lure hub 59 for connecting the lumen to a Y-shaped connector and hemostatic valve, as is well known in the field of angioplasty. The OD of a delivery catheter with a slidable sheath can be in the range of 2-4F (French size) or larger if the peripheral arteries are treated.</p><p> Since the drug coil is completely biodegradable, it does not affect the patient's opportunity for surgery, which does not cause subsequent complications to the blood vessels, like the all-metal jacket. Bare metal coils are often placed intravascularly to cause thromboembolism and complete blockade in certain neurovascular applications, but surprisingly, biocompatible polymers (poly (dl-lactic acid)) ( PDLA) and mixtures thereof), in the disclosed configurations, provide sufficient mechanical strength to support damaged blood vessels after angioplasty and, in addition, do not cause embolism, and thus the present invention. It has been demonstrated to be an exemplary material for the manufacture of drug coils.</p><p> Once deployed at that site, the stent begins to release the active compound into the cells that line the vascular site, suppressing cell proliferation. Figure 8A shows the everolimus release kinetics from two stents constructed according to the present invention, each with a coating about 10 microns thick (black square). Drug release kinetics was obtained by immersing the stent in a 25% ethanol solution, which greatly accelerates the rate of drug release from the stent coating. This graph shows the types of drug release kinetics that can be predicted in vivo, but over a longer time scale.</p><p> FIG. 8B shows the drug release of everolimus from the coatings of the invention on a metal stent substrate. The upper set of curves shows the drug release when the coating is applied directly to the metal surface. A set of lower curves (showing slower release) was obtained by applying a underlayer or primer coat of parylene to the surface of the metal stent and then coating the surface with the coating system of the present invention. As can be seen, the primer increases the mechanical adhesion of the coating to the stent surface, resulting in slower degradation of the bioerodible coating and slower release of the drug. If such a configuration is desirable to have a strongly adherent stent coating, it can withstand repeated wear of the drug-eluting stent during the tortuous operation of the guide catheter and / or inside the vessel. ), And / or where it is desirable to slow drug release for prolonged treatment of the atherosclerotic disease process at the site of implantation after implantation of the device.</p><p> FIG. 9 shows a cross section of the vascular region 60 with the implanted stent 62. Coated filaments of this stent (eg, filament 64 with coating 66) can be seen in cross section. This figure shows the release of anti-stenotic compounds from each filament region to the surrounding vascular wall region. Over time, smooth muscle cells that form the vascular wall begin to grow inside and through the lattice or spiral openings of the stent, eventually forming a continuous inner cell layer. This layer wraps the stent on both sides. If the stent is successfully transplanted, the degree of vascular obstruction at that site later is less than 50%. That is, the cross-sectional diameter of the flow channel remaining inside the vessel is at least 50% of the expanded stent diameter at the time of implantation.</p><p> Findings in a pig restenotic animal model as commonly described by Schwartz et al. ("Restenosis After Balloon Angioplasty-A Practical Proliferative Model in Porcine Coronary Arteries", Circulation 82: (6) 2190-2200, December 1990) The ability of the stent of the invention to limit the degree of restenosis, and the advantages of this stent over the stents currently being proposed and tested (especially severe vascular injury (ie, vascular elongation greater than 35%). In the case of)) is demonstrated. These studies are summarized in Example 4.</p><p> Simply put, these studies include bare metal stents, polymer-coated stents, and high or low concentrations of sirolimus (sirolimus) and everolimus, with a degree of restenosis 28 days after stent implantation. Compare in polymer coated stents.</p><p> Table 1 of Example 4 shows that both the rapamycin stent (Rapa-high or Rapa-low) and the everolimus stent (C-high or C-low) significantly reduced the level of restenosis. Minimal doses of restenosis were observed at high doses of everolimus stents. Similar results were obtained in studies on animals with low damage (Table 2).</p><p> Figures 10A-10C are examples of day 28 endocardial stent cross-sections of exposed metal S-shaped stents (available from Biosensors International Inc, Newport Beach, CA). Figures 11A-11C are examples of endocardial formation in polymer-coated (drug-free) S-shaped stents; and Figures 12A-12C and 13A-13C are intracardiac in everolimus / polymer-coated stents. This is an example of film formation. In general, vasculature treated with an everolimus-coated stent appears to have healed well, with a well-established endothelial layer. Evidence of complete healing and vascular hemostasis is on day 28. FIG. 13 is an example of a vascular cross section at 91x magnification, showing the healing and establishment of the endothelial layer inward of the vascular lumen 28 days after implantation.</p><p> These photographs show that the most preferred combination for elimination of restenosis on day 28 is the C-high or C-Ulight formulation (see Example 4) (these are 18.7 mm long). The stent contained 325 micrograms and 275 micrograms of everolimus, respectively). This data predicts a 50% reduction in restenosis on day 28 of follow-up in young non-inbred pigs compared to bare metal stents (S-shaped stents) currently on the market. .. This data also shows that the drug everolimus is better than, or at least equivalent to, 180 micrograms of sirolimus on the same stent / polymer delivery platform. These results are supported by inferential analysis (Example 4).</p><p> FIG. 15 shows the optimal linear regression curve for selected dosing of factors in a polymer coated on an S-shaped stent. This curve correlates the injury score with the area of stenosis during follow-up. A "stenotic region" is an accurate indicator of endocardial formation, as determined by inferential analysis. As can be seen from this figure, the high everolimus stent was the only coating in the group of samples tested that showed a negative slope with respect to the increased injury score. This analysis suggests that the C-high coating can control restenosis in the injured coronary arteries, which is virtually independent of the injury score. None of the other coating formulations attempted showed this unique feature.</p><p> FIG. 16 shows the relationship between vascular balloon hyperextension as measured by the balloon / arterial ratio (B / A ratio) and vascular injury in animal studies. This data is a reasonably accurate method of producing predictable and known vascular injuries in a porcine model that can result in highly controlled vasculature using an over-dilated angioplasty balloon. Indicates that there is.</p><p> FIG. 17 shows the elution profiles of everolimus (black circles) and 40-O-hydroxyheptyl rapamycin (black squares) from a polymer coating of poly (dl-lactic acid) made on a stent. Elution of the compound from the polymer into ethanol / water (25/75 ratio) was measured as a function of time. The release of 40-O-hydroxyheptyl rapamycin at 8 hours was about 1.7 times greater than everolimus. At a later point in time, the release of 40-O-hydroxyheptyl rapamycin was about 1.5-fold greater than the release of everolimus. Accordingly, the present invention contemplates a polymeric composition consisting of a polymeric substrate and a 40-O-hydroxyalkyl substituted rapamycin compound, which composition is at least 1.5 times greater than the release of everolimus from the polymeric substrate at room temperature. Releases the compound into ethanol / water at the rate of.</p><p> From the above, it can be seen how the various objectives and features of the present invention are adapted. A polymeric substrate containing a 40-O-hydroxyalkyl substituted rapamycin compound having an Rm value substantially greater than the Rm value of everolimus or rapamycin is intended to be used in the composition for administration to the target treatment site. .. When placed in adjacent tissues that require treatment, the 40-O-hydroxyalkyl-substituted rapamycin compound elutes from the polymer substrate into the tissue. The composition is suitable for the treatment of any condition (including neoplastic disease) that responds to treatment with rapamycin or everolimus, including inflammation, infection, wound healing, transplant rejection and restenosis. Be done. The condition intended for treatment may be that the polymeric composition is locally deposited or placed at the site where treatment is needed (eg, the site of wound, tumor or restenosis, inflammation or infection). Including state.</p>

The following examples show various aspects of making and using the invention of a stent herein. These are not intended to limit the scope of the invention.

(Example 1) (Preparation of everolimus and its derivatives) (Synthesis of Step A.2- (t-Butyldimethylsilyl) Oxyethanol (TBS Glycol)) 154 ml of dry THF and 1.88 g of NaH are stirred in a 500 mL round bottom flask condenser under a nitrogen atmosphere. 4.4 mL of dry ethylene glycol is added to this flask and after 45 minutes of stirring a large precipitate is formed. 11.8 g of tert-butyldimethylsilyl chloride is added to this flask and vigorous stirring is continued for 45 minutes. The resulting mixture is poured into 950 mL of ethyl ether. The ether is washed with 420 mL brine and the solution is dried over sodium sulphate. This product is concentrated by evaporation of ether under reduced pressure, and using a 27 x 5.75 cm column packed with silica gel, hexane / Et.₂Purify by flash chromatography using an O (75:25 v / v) solvent system. Store the product at 0 ° C.

(Synthesis of Step B.2- (t-Butyldimethylsilyl) Oxyethyl Triflate (TBS Glycol Trif)) Combine 4.22 g of TBS glycol and 5.2 g of 2,6-lutidine in a 100 mL two-necked flask equipped with a condenser under nitrogen with vigorous stirring. 10.74 g of trifluoromethanesulfonic anhydride is slowly added to this flask over 35-45 minutes to give a yellowish brown solution. The reaction is then quenched by adding 1 mL of brine and the solution is washed 5 times in 100 mL of brine to a final pH value of 6-7. The solution is dried over sodium sulphate and concentrated by evaporation of methylene chloride under reduced pressure. The product was hexane / Et using a silica gel-filled flash chromatography column of approximately 24 x 3 cm.₂Purify using an O (85: 15 v / v) solvent system and then store at 0 ° C.

(Synthesis of step C.40-O- [2- (t-butyldimethylsilyl) oxy] ethyl-rapamycin (TBS Rap)) 400 mg rapamycin, 10 mL toluene, and 1.9 mL 2,6-lutidine are mixed in a 50 mL flask maintained at 55-57 ° C and stirred. In another 3 mL septum vial, 940 μL of 2,6-lutidine is added to 1 mL of toluene, followed by 2.47 g of TBS glycol Trif. The contents of this vial are added to a 50 mL flask and the reaction is allowed to proceed for 1.5 hours with stirring. Add 480 μL of 2,6-lutidine and an additional 1.236 g of TBS glycol Trif to this reaction flask. Continue stirring for an additional hour. Finally, a second portion of 480 μL of 2,6-lutidine and 1.236 g of TBS glycol Trif are added to the mixture, and the mixture is stirred for an additional 1-1.5 hours. The resulting brown solution is poured through a porous glass filter using reduced pressure. The crystalline precipitate is washed with toluene until all colors are removed. The filtrate is then subjected to 60 mL of saturated LVDS.₃Wash twice with solution and then again with brine. The resulting solution is dried over sodium sulphate and concentrated under reduced pressure. The product was dissolved using a small amount of hexane / EtOAc (40: 60v / v) solvent and then developed using a 33 x 2 cm flash chromatography column packed with silica gel and developed in the same solvent for purification. Achieve. The solvent is removed under reduced pressure and the product is stored at 5 ° C.

(Step D.40-O- (2-hydroxyl) ethyl-rapamycin (everolimus) synthesis process.) A Pyrex® glass dish (150 x 75 mm) is filled with ice and placed on a stirring plate. Add a small amount of water to obtain an ice slurry. First, 60-65 mg of TBS-Rap is dissolved in a glass vial by adding 8 mL of methanol. 0.8 mL 1N HCl was added to the vial and the solution was stirred for 45 minutes, then 3 mL saturated LVDS.₃Neutralize by adding aqueous solution. 5 mL of brine followed by 20 mL of EtOAc is added to the solution, resulting in the formation of two phases. After mixing these phases, remove the aqueous layer using a separatory funnel. The remaining solvent is washed with brine to a final pH of 6-7 and dried over sodium sulphate. Sodium sulphate is removed using a porous glass filter and the solvent is removed in vacuo. The resulting concentrate is dissolved in EtOAc / Methanol (97: 3) and then developed and purified using the same solvent system using a 23 x 2 cm flash chromatography column packed with silica gel. The solvent is removed in vacuo and the product is stored at 5 ° C.

(Example 2) (Preparation of stents containing everolimus in poly-dl-lactide coating) 100 mg of poly (dl-lactide) was dissolved in 2 mL acetone at room temperature. 5 mg everolimus was placed in a vial and 400 μL of lactide solution was added. A microprocessor-controlled syringe pump was used to accurately dispense 10 μL of the drug containing the lactide solution onto the top surface of the stent strut. Evaporation of the solvent resulted in a uniform drug containing a single polymer layer on the stent.

A volume of 15 μL was used in a similar fashion to coat the stent top strut surface and stent side strut surface, resulting in a single layer coating the stent strut top and stent strut side.

(Example 3) (In vitro drug release from stent containing everolimus in poly-dl-lactide coating) In vitro drug release by placing the coated stent in 2 mL pH 7.4 phosphate buffered saline containing 25% EtOH, storing with 0.05% (w / v) sodium azido and keeping at 37 ° C. Was done. Sampling was performed periodically by replacing the solution with the same volume of fresh buffer (infinite sedimentation) while collecting the total buffer volume for drug measurement. FIG. 8 illustrates drug release from two similar stents coated with a single polymer layer microdispersed in this manner.

(Example 4) (Animal transplant test) (A. QCA results of safety and dose-ranging study in pigs) A problematic treatment condition for drug-eluting stents is severely damaged vessels because the degree of restenosis (new intima formation) increases directly with the degree of vascular injury. Experiments were performed in pigs and a significant number of vessels that were the target of drug-coated stent implants were severely injured using angioplasty balloons (average approximately 36% overstretched). Damage to the vessel). This caused severe tearing and stretching of the intima and middle layer of the vasculature, resulting in extreme restenosis 28 days after transplantation. Thus, it was possible to assess the relative efficacy of various doses of the drug and the weight ratio of the drug to the polymer on the same metal stent / polymer platform for reduced restenosis 28 days after implantation.

(Test platform abbreviation) A "bare stent" is a 18.7 mm bare metal stent with a corrugated ring design (ie, a "S-stent" currently on the market, such as that manufactured by Biosensors Intl., Inc.).

C-high means a 18.7 mm long stent with 325 μg everolimus in a PDLA (poly-dl-lactic acid) polymer coating.

C-low means a 18.7 mm long stent with 180 μg everolimus in a PDLA polymer coating.

"Rapamycin-high" refers to a 18.7 mm long stent with 325 μg sirolimus in a PDLA polymer coating.

"Rapamycin-low" refers to a 18.7 mm long stent with 180 μg sirolimus in a PDLA polymer coating.

"CU light" refers to a 18.7 mm long stent with 275 μg everolimus (37% drug weight ratio to polymer) in an ultra-thin coating of PDLA polymer.

CU low refers to a 18.7 mm long stent with 180 μg everolimus or its equivalent (drug weight ratio to 37% polymer) in an ultrathin coating of PDLA polymer.

"Polymer Stent" means a 18.7 mm S-Stent covered solely with a PDLA polymer coating.

"B / A" is the ratio of the last inflated balloon to the artery and is an indicator of the degree of excessive vascular elongation.

"Average lumen loss (MLL)" is determined by subtracting the average of the three measurements obtained by subsequent angiography from the average of the three measurements obtained in the stent internal lumen at the time of implantation. And shows the amount of new lumen intima formed inside the stent.

(Method:) Drug-eluting stents (ie, S-stents) and polymer coatings using a metal wire mesh skeleton with a corrugated ring design, immature pigs grown outside using either different doses of drug everolimus or drug sirolimus (Or for transplant studies lasting longer than 28 days, Yucatan Mini pig) was transplanted. At the time of transplantation, Quantitative Coronary Angiography (QCA) was performed to measure the diameter of the vessels before and after stenting. On day 28, or longer, as specifically indicated in the table below, the animal is re-acquired QCA in the area of the stent and then euthanized.

Following animal euthanasia according to an approved protocol, the heart was removed from the animal and a pressurized formaldehyde solution was injected into the coronary arteries. A segment of the coronary artery containing the stent was then surgically removed from the surface of the heart and subsequently fixed in an acrylic plastic block for cross-sectioning with a diamond blade. A 50 micron thick section of acrylic material containing the cut surface of the vessel located proximally, centrally and distally was then optically polished and placed on a microscope slide.

A microscope equipped with a digital camera was used to produce high resolution images of cross-vascular sections mounted on slides. These images were subjected to histomorphometric analysis by the following procedure: Image Pro Plus 4.0, a computerized imaging system via an AGHeinze slide microscope for PC-based systems, was used for the following tissue morphometry measurements: 1. Average cross-sectional area and lumen thickness (intima / new intima-region limited by lumen boundary); new intima (between lumen and endoelastic plate (IEL)) Region, the region between the lumen and the rest of the intermediate or outer elastic plate (EEL), if IEL is missing); intermediate (area between IEL and EEL); tube size (adventitial region) Excludes areas restricted by EEL); and adventitial areas (areas between peripheral adventitial tissue, adipose tissue and myocardial layer and EEL). 2. Damage score. Scores based on the amount and length of crevices in different wall structures were used to quantify the extent of vascular injury. The degree of damage was calculated as follows: 0 = Intact IEL 1 = Ripped IEL (less damage) exposed to surface medium layer 2 = Ripped IEL (media incision) exposed to a deeper medium layer 3 = Ripped EEL exposed to the adventitial region The table below shows the results of QCA analysis (measurement of mean luminal loss due to restenosis) with follow-up QCA. The data under the column entitled "New Vascular Intima Region" in the table below report the results of morphometry analysis of stents and tubes removed from pigs in follow-up management (f / u): (Table 1: Results of "Severe Damage" Experiment)

<tables num="2"><img file="JP5113667B2_D0007.tif" /></tables> (B. Low damage study) To further determine how much everolimus dose is best in lightly injured vessels (more specific to patients with uncomplicated coronary artery disease and one new injury), medium everolimus-eluting stents. Transplanted to create moderate to low hyperextension injury (approximately 15%). Farm pigs were used for a 30-day experiment, and adult Yucatan mini pigs were transplanted for a 3-month safety study. The results of angiography were as follows: (Table 2: QCA results for "low damage" experiments)

<tables num="3"><img file="JP5113667B2_D0008.tif" /></tables> The above data predicted that either the C-Ulow or C-Uhigh dose of everolimus produced a 45-48% reduction in neointima formation in low to moderately injured tubes.

(C. Morphological measurement analysis) The total cut surface area within each stent and the cut surface area of the new tissue (new vessel intima) formed within the stent was measured by a computer and the proportion of the stenotic area was calculated. The following table shows the average tube injury score, the neovascular intima region, and the ratio of the stenotic region averaged 3 slices per stent to each formation of drug and polymer.

(Table 3: Results of "Severe Damage" Experiment)

<tables num="4"><img file="JP5113667B2_D0009.tif" /></tables> Morphological analysis is considered to be a highly accurate method of measuring intrastent stenosis in a porcine coronary model. In the severe injury model, the C-High formulation produced the lowest amount of neovascular intimal formation in the "high injury" experiment at 28 days; however, C-Uhigh gave the group the highest injury score. It had a very low proportion of constricted areas of 0.45 and was still managed. Therefore, the data independently confirm the findings of the QCA analysis and support the selection of C-Uhigh as the preferred formulation for human clinical trials. (D. Histological analysis) Slides about C-U high and sirolimus-low were submitted to an experienced cardiologist. He reviewed the canal cross-section for evidence of inflammation, fibrin and endothelialization of the newly treated vascular lumen. No difference was found between the histological changes caused by the sirolimus-eluting stent and the everolimus-eluting stent. In general, tubes with a well-established endothelial layer are well-treated, evidence of complete cure, and appear to be tube homeostasis at 28 days. FIG. 14 is an example of a 91x tube cross section showing treatment and fixation of the endothelial layer inside the lumen 28 days after transplantation.

(E. Comparison with published results) Carter et al. Published results for sirolimus-coated stents in pigs using Palmaz Schatz metal stents. A table comparing the published Carter results to the experimental results using polymer-coated stents herein is shown below: (Table 4)

<tables num="5"><img file="JP5113667B2_D0010.tif" /></tables> (Example 5) (Preparation of stents with advanced drug loading) A 14.6 mm long commercially available metal corrugated ring stent (S-stent, corrugated ring design: Biosensors Intl) was coated with a layer approximately 2 microns thick of parylene "C" primer coating using a plasma deposition process. .. The parylene-coated stent was placed in xylene overnight at ambient temperature. A PDLA solution containing 50 μg / μl of polylactic acid (PDLA) was prepared by dissolving in 100 mg of PDLA in 2 mL acetone.

To prepare a stent containing a drug ratio to 50% polymer, 5 mg everolimus was dissolved in 100 μl PDLA storage solution. An additional 20 μL of acetone was added to assist in formulating the solution. The stent was removed from xylene and carefully blotted to remove solvent. A total of 5.1 μl of coating solution was prepared on the outer surface of each stent. The stent was dried at ambient temperature and placed in a desiccator overnight. This resulted in a total of 212 μg everolimus contained in 212 μg PDLA per stent.

To prepare a stent containing a drug ratio to 75% polymer, 5 mg everolimus and 33.3 μL of stored PDLA solution were mixed. An additional 33.3 μL of acetone was added to dissolve the mixture. The stent was removed from xylene and blotted as above. A total of 2.8 μL of coating solution was prepared on the outer surface of each stent. The stent was dried at ambient temperature and placed in a desiccator overnight. This resulted in a total of 212 μg everolimus contained in 70 μg PDLA per stent.

The final stent exhibited an everolimus / PDLA approximately 5 micron thick coating or a slightly emulsion-colored appearance, which was smoothly distributed on the top and side surfaces and tightly bonded to the metal strut surface.

<figref num="1">Figure 1 shows 40-O-hydroxyheptyl (black circle), everolimus (40-O-hydroxyethylrapamycin; white square), rapamycin (sirolimus; black Mitsubishi), paclitaxel (white triangle) and dexamethasone (black square). It is a half logarithmic plot of relative hydrophobicity (Rm value) as a function of acetone concentration (balance water) of.</figref><figref num="2">FIG. 2 illustrates an intravascular stent having a metal filament body and formed according to one embodiment of the invention (the stent exhibits a contracted state).</figref><figref num="3">FIG. 3 illustrates an intravascular stent having a metal filament body and formed according to one embodiment of the invention, the stent showing an expanded state.</figref><figref num="4">FIG. 4 is an enlarged cross-sectional view of the coated metal filament of the stent of FIG.</figref><figref num="5">FIG. 5 is an enlarged cross-sectional view of a coated bioerodible polymer stent.</figref><figref num="6A">6A and 6B are schematic representations of polymer coating methods suitable for use in the production of polymer coated stents.</figref><figref num="6B">6A and 6B are schematic representations of polymer coating methods suitable for use in the production of polymer coated stents.</figref><figref num="7">FIG. 7 shows a bioerodible polymer stent attached to a catheter for delivery to the vascular site.</figref><figref num="8A">FIG. 8A is a plot showing the release of everolimus from a stent holding a polymer coating.</figref><figref num="8B">FIG. 8B is a plot showing the release of everolimus from a stent holding a polymer coating.</figref><figref num="9">FIG. 9 is a cross-sectional view of the stent deployed at the vascular site.</figref><figref num="10A">Figures 10A-10C are histological sections of blood vessels 28 days after implantation of a bare metal stent.</figref><figref num="10B">Figures 10A-10C are histological sections of blood vessels 28 days after implantation of a bare metal stent.</figref><figref num="10C">Figures 10A-10C are histological sections of blood vessels 28 days after implantation of a bare metal stent.</figref><figref num="11A">11A-11C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating.</figref><figref num="11B">11A-11C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating.</figref><figref num="11C">11A-11C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating.</figref><figref num="12A">Figures 12A-12C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating containing evalolimus.</figref><figref num="12B">Figures 12A-12C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating containing evalolimus.</figref><figref num="12C">Figures 12A-12C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating containing evalolimus.</figref><figref num="13A">Figures 13A-13C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating containing evalolimus.</figref><figref num="13B">Figures 13A-13C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating containing evalolimus.</figref><figref num="13C">Figures 13A-13C are histological sections of blood vessels 28 days after implantation of a metal filament stent with a polymer coating containing evalolimus.</figref><figref num="14">FIG. 14 is an enlarged histological section of the vessel found in the filament of the stent utilized in FIGS. 12A-12C, which is overgrown by new tissue forming the healing vessel wall.</figref><figref num="15">FIG. 15 is a plot of the stenotic region 28 days after transplantation as a function of injury score using a variety of different stents.</figref><figref num="16">FIG. 16 shows a correlation plot between the injury score (Y-axis) and the B / A (balloon / artery) ratio during stent implantation.</figref><figref num="17">FIG. 17 shows the total amount of released drug (μg), everolimus (40-O-hydroxyethyl rapamycin; black circle) and 40-O-hydroxyheptyl rapamycin; (black square) as a function of time (time). A plot of the polymer substrate (poly-dl-lactic acid) held on the stent is shown.</figref>