Patent Publication Number: US-11039870-B2

Title: Drug eluting surgical screw

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 15/808,932 filed on Nov. 10, 2017, which is a continuation of U.S. application Ser. No. 15/174,054, filed on Jun. 6, 2016, now U.S. Pat. No. 9,833,271, which is a continuation of U.S. application Ser. No. 13/800,342, filed Mar. 13, 2013, now U.S. Pat. No. 9,364,273, which claims the benefit of U.S. Provisional Patent Application No. 61/683,262, filed Aug. 15, 2012, the contents of each of which are incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     The risks of infection following surgery are well documented. The presence of a foreign object such as a fracture fixation plate (e.g., an orthopedic fracture fixation plate) in the wound site may increase the risk of infection following surgery by providing a substrate for bacteria to adhere and proliferate, form a biofilm, and evade the host immune system. The risk of infection may increase in the case of open fractures where bacterial contamination of the wound prior to surgery is common. The consequences of implant related infection can be significant, with recurring infection leading to chronic osteomyelitis, impaired healing, and potentially limb amputation. Antibiotic eluting implants have been developed to address this concern. 
     SUMMARY 
     One embodiment of the present invention is a drug eluting surgical screw including a shaft having a threaded portion; a head having a drive recess disposed at a proximal end of the shaft, the drive recess having a reservoir region and a driver engagement region; and at least one or more drug eluting components disposed within the reservoir region of the drive recess in a manner that does not substantially impair a connection between a driver and the surgical screw when the driver is operably disposed within the driver engagement region, each of the at least one or more drug eluting components including a carrier matrix and a therapeutic agent, the therapeutic agent being at least about 20 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, at least one of the at least one or more drug eluting components is configured to elute at least about 80% of its therapeutic agent over a three day period starting from when the drug eluting surgical screw is implanted into an animal. 
     In one embodiment, the concentration of the therapeutic agent of at least one of the at least one or more drug eluting components is between about 20 wt % and about 60 wt % of the at least one of the at least one or more drug eluting components prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, the concentration of the therapeutic agent of at least one of the at least one or more drug eluting components is between about 20 wt % and about 40 wt % of the at least one of the at least one or more drug eluting components prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, the reservoir region defines a reservoir volume, the drive recess defines a drive recess volume and the reservoir volume is from about 10% to about 12% of the drive recess volume. In one embodiment, the reservoir region of the drive recess is adjacent to the driver engagement region and the at least one or more drug eluting components do not extend into the driver engagement region. In one embodiment, the carrier matrix of at least one of the at least one or more drug eluting components includes a bioabsorbable polymer. In one embodiment, the bioabsorbable polymer includes polycaprolactone, polylactic acid, polyglycolic acid, polyethylene glycol, or a combination thereof. In another embodiment, the carrier matrix of at least one of the at least one or more drug eluting components includes polyethylene glycol, polyvinyl alcohol, glycerine, salts or a water soluble crystalline solid. In another embodiment, the carrier matrix of at least one of the at least one or more drug eluting components includes silica, hydroxyapatite, calcium phosphate, bioglass or a combination thereof. In another embodiment, the carrier matrix of at least one of the at least one or more drug eluting components includes a hydrophobic bioabsorbable polymer. In one embodiment, the hydrophobic bioabsorbable polymer includes a water swellable additive which swells with water after implantation into the body. In one embodiment, the carrier matrix of at least one of the at least one or more drug eluting components includes a nonabsorbable polymer. In one embodiment, the nonabsorbable polymer includes poly(methyl methacrylate). In one embodiment, the carrier matrix of at least one of the at least one or more drug eluting components includes a nonabsorbable polymer and a bioabsorbable polymer. In one embodiment, the bioabsorbable polymer includes polycaprolactone, polylactic acid, polyglycolic acid, polyethylene glycol, or a combination thereof. In one embodiment, the bioabsorbable polymer of at least one of the at least one or more drug eluting components includes an erodible ceramic. In one embodiment, the bioabsorbable polymer of at least one of the at least one or more drug eluting components includes a biostable ceramic. In one embodiment, the bioabsorbable polymer of at least one of the at least one or more drug eluting components includes a natural biopolymer. In one embodiment, the natural biopolymer includes gelatin, alginates, chitosan, collagen or hyaluronate. 
     In one embodiment, at least one of the one or more drug eluting components includes a nonabsorbable polymer and a soluble additive. In another embodiment, the nonabsorbable polymer includes poly(methyl methacrylate). In another embodiment, the soluble additive includes polyethylene glycol, polyvinyl alcohol, glycerine, salts or a water soluble crystalline solid. 
     In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a concentration gradient. 
     In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes gentamicin. In another embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a steroid. In another embodiment, the steroid is an angiostatic steroid. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes an anti-inflammatory drug. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes an anti-proliferative compound. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes an antimycotic compound. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes an antimitotic compound. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes an antimetabolite compound. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a pain-relieving drug. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a corticosteroid. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a non-steroidal anti-inflammatory agent. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a co-drug. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a growth factor. In one embodiment, the growth factor includes bone morphogenetic protein 2. In one embodiment, the therapeutic agent of at least one of the at least one or more drug eluting components includes a local anesthetic. In one embodiment, the local anesthetic includes lidocaine. 
     In one embodiment, the reservoir region is shaped and dimensioned to retain the at least one or more drug eluting components when the at least one or more drug eluting components are in a cured condition. 
     In one embodiment, the drug eluting surgical screw further includes a lip configured and dimensioned to retain the drug eluting component when the at least one or more drug eluting components are in a cured condition. 
     In one embodiment, the drug eluting surgical screw further includes at least two drug eluting components. 
     In one embodiment, the present invention is a method of manufacturing a drug eluting surgical screw, said method including mixing a drug eluting component with a solvent to form a solution, the drug eluting component including a carrier matrix and a therapeutic agent, the therapeutic agent being at least about 20 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw; heating the solution to evaporate the solvent and form a film; configuring at least a portion of the film to a size and shape that complements a drive recess of a surgical screw; placing the at least a portion of the film into the drive recess of the surgical screw; heating the at least a portion of the film to conform to the size and shape of a cross-section of the drive recess; and pressing the at least a portion of the heated film into the drive recess with a forming tool. A forming tool is preferably used to apply sufficient pressure to the heated film to create a bond between the film and the surgical screw. 
     In one embodiment, the present invention is a method of manufacturing a drug eluting surgical screw, said method including compounding a drug eluting component, the drug eluting component including a carrier matrix and a therapeutic agent, the therapeutic agent being at least about 20 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw; extruding the compounded drug eluting component to form a film; configuring at least a portion of the film to a size and shape that complements a drive recess of a surgical screw; placing the at least a portion of the film into the drive recess of the surgical screw; heating the at least a portion of the film to conform to the size and shape of a cross-section of the drive recess; and pressing the at least a portion of the heated film into the drive recess with a forming tool. 
     In one embodiment, the present invention is a method of manufacturing a drug eluting surgical screw, said method including compounding a drug eluting component, the drug eluting component including a carrier matrix and a therapeutic agent, the therapeutic agent being at least about 20 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw; compression molding the compounded drug eluting component to form a film; configuring at least a portion of the film to a size and shape that complements a drive recess of a surgical screw; placing the at least a portion of the film into the drive recess of the surgical screw; heating the at least a portion of the film to conform to the size and shape of a cross-section of the drive recess; and pressing the at least a portion of the heated film into the drive recess with a forming tool. 
     In one embodiment, each step is repeated sequentially to add an additional drug eluting component to the drive recess of the surgical screw. 
     In one embodiment, the drug eluting component is configured to elute at least about 80% of the therapeutic agent over a three day period starting from when the drug eluting surgical screw is implanted into an animal. 
     In one embodiment, the concentration of the therapeutic agent is between about 20 wt % and about 60 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, the concentration of the therapeutic agent is between about 20 wt % and about 40 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, the carrier matrix includes a bioabsorbable polymer. In one embodiment, the bioabsorbable polymer includes polycaprolactone, polylactic acid, polyglycolic acid, polyethylene glycol, or a combination thereof. In one embodiment, the carrier matrix includes polyethylene glycol, polyvinyl alcohol, glycerine, salts or a water soluble crystalline solid. In one embodiment, the carrier matrix includes silica, hydroxyapatite, calcium phosphate, bioglass or a combination thereof. In one embodiment, the carrier matrix includes a hydrophobic bioabsorbable polymer. In one embodiment, the hydrophobic bioabsorbable polymer includes a water swellable additive which swells with water after implantation into the body. In one embodiment, the carrier matrix includes a nonabsorbable polymer. In another embodiment, the nonabsorbable polymer includes poly(methyl methacrylate). In one embodiment, the carrier matrix includes a nonabsorbable polymer and a bioabsorbable polymer. In one embodiment, the bioabsorbable polymer includes polycaprolactone, polylactic acid, polyglycolic acid, polyethylene glycol, or a combination thereof. In one embodiment, the bioabsorbable polymer includes an erodible ceramic. In one embodiment, the bioabsorbable polymer includes a biostable ceramic. In one embodiment, the bioabsorbable polymer includes a natural biopolymer. In another embodiment, the natural biopolymer includes gelatin, alginates, chitosan, collagen or hyaluronate. 
     In one embodiment, the drug eluting component includes a nonabsorbable polymer and a soluble additive. In one embodiment, the nonabsorbable polymer includes poly(methyl methacrylate). In one embodiment, the soluble additive includes polyethylene glycol, polyvinyl alcohol, glycerine, salts or a water soluble crystalline solid. 
     In one embodiment, the drug eluting component includes a concentration gradient. 
     In one embodiment, the therapeutic agent includes gentamicin. In another embodiment, the therapeutic agent includes a steroid. In one embodiment, the steroid is an angiostatic steroid. In one embodiment, the therapeutic agent includes an anti-inflammatory drug. In one embodiment, the therapeutic agent includes an anti-proliferative compound. In one embodiment, the therapeutic agent includes an antimycotic compound. In one embodiment, the therapeutic agent includes an antimitotic compound. In one embodiment, the therapeutic agent includes an antimetabolite compound. In one embodiment, the therapeutic agent includes a pain-relieving drug. In one embodiment, the therapeutic agent includes a corticosteroid. In one embodiment, the therapeutic agent includes a non-steroidal anti-inflammatory agent. In one embodiment, the therapeutic agent includes a co-drug. In one embodiment, the therapeutic agent includes a growth factor. In one embodiment, the growth factor includes bone morphogenetic protein 2. In another embodiment, the therapeutic agent includes a local anesthetic. In one embodiment, the local anesthetic includes lidocaine. 
     One embodiment of the present invention is drug eluting surgical screw including a shaft having a threaded portion; a head having a drive recess disposed at a proximal end of the shaft, the drive recess having a reservoir region and a driver engagement region; and a drug eluting component disposed within the reservoir region of the drive recess in a manner that does not substantially impair a connection between a driver and the surgical screw when the driver is operably disposed within the driver engagement region, the drug eluting component including a carrier matrix and a therapeutic agent, the therapeutic agent being at least about 20 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, the drug eluting component is configured to elute at least about 80% of the therapeutic agent over a three day period starting from when the drug eluting surgical screw is implanted into an animal. In another embodiment, the concentration of the therapeutic agent between about 20 wt % and about 60 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. In another embodiment, the concentration of the therapeutic agent is between about 20 wt % and about 40 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, the reservoir region defines a reservoir volume, the drive recess defines a drive recess volume and the reservoir volume is from about 10% to about 12% of the drive recess volume. 
     In another embodiment, the reservoir region of the drive recess is adjacent to the driver engagement region and the drug eluting component does not extend into the driver engagement region. 
     In certain embodiments, the carrier matrix includes polycaprolactone, polylactic acid, polyglycolic acid, polyethylene glycol, or a combination thereof. 
     In one embodiment, the therapeutic agent includes gentamicin. 
     In other embodiments, the reservoir region is shaped and dimensioned to retain the drug eluting component when the drug eluting component is in a cured condition. 
     In another embodiment, the drug eluting surgical screw further includes a lip configured and dimensioned to retain the drug eluting component when the drug eluting component is in a cured condition. 
     In one embodiment, the invention is directed to a method of manufacturing a drug eluting surgical screw, the method including mixing a drug eluting component with a solvent to form a solution, the drug eluting component including a carrier matrix and a therapeutic agent, the therapeutic agent being at least about 20 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw; heating the solution to evaporate the solvent and form a film; configuring at least a portion of the film to a size and shape that complements a drive recess of a surgical screw; placing the at least a portion of the film into the drive recess of the surgical screw; heating the at least a portion of the film to conform to the size and shape of a cross-section of the drive recess; and pressing the at least a portion of the heated film into the drive recess. A forming tool is preferably used to apply sufficient pressure to the heated film to create a bond between the film and the surgical screw. 
     In one embodiment, the drug eluting component is configured to elute at least about 80% of the therapeutic agent over a three day period starting from when the drug eluting surgical screw is implanted into an animal. In another embodiment, the therapeutic agent is from about 20 wt % to about 60 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. In another embodiment, the concentration of the therapeutic agent is between about 20 wt % and about 40 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw. 
     In one embodiment, the carrier matrix includes polycaprolactone, polylactic acid, polyglycolic acid, polyethylene glycol, or a combination thereof. 
     In certain embodiments, the therapeutic agent includes gentamicin. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing summary, as well as the following detailed description of embodiments of the present invention, will be better understood when read in conjunction with the appended drawings of exemplary embodiments. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. 
       In the drawings: 
         FIG. 1A  is a top view and  FIG. 1B  is a side perspective partial cross-sectional view of a surgical screw according to one embodiment; 
         FIG. 2A  is a top view and  FIG. 2B  is a side perspective partial cross-sectional view of an embodiment of a surgical screw having a drug eluting matrix in the drive recess; 
         FIG. 3A  is a top view and  FIG. 3B  is a side perspective partial cross-sectional view of an embodiment of a surgical screw having a drug eluting matrix in the drive recess with a diffusion barrier layer; 
         FIG. 4A  is a top view and  FIG. 4B  is a side perspective partial cross-sectional view of an embodiment of a surgical screw having two layers of drug eluting matrix in the drive recess, containing two different drugs; 
         FIG. 5A  is a top view and  FIG. 5B  is a side perspective partial cross-sectional view of an embodiment of a surgical screw having a drug eluting matrix in the drive recess with a graded drug concentration; 
         FIG. 6A  is a top view and  FIG. 6B  is a side perspective partial cross-sectional view of an embodiment of a surgical screw having an additional reservoir added to the bottom of the drive recess and having a drug eluting matrix in the drive recess; 
         FIG. 7A  is a top view and  FIG. 7B  is a side perspective partial cross-sectional view of an embodiment of a surgical screw having a lip configured and dimensioned to retain a drug eluting component when the drug eluting component is in a cured condition; and, 
         FIG. 8  is a schematic side perspective cross-sectional view of a surgical screw securing a fracture fixation implant to bone according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     With reference to the accompanying drawings, various embodiments of the present invention are described more fully below. Some but not all embodiments of the present invention are shown. Indeed, various embodiments of the invention may be embodied in many different forms and should not be construed as limited to the embodiments expressly described. Like numbers refer to like elements throughout. The singular forms “a,” “an,” and “the” include the singular and plural unless the context clearly dictates otherwise. 
     As shown generally in  FIGS. 1A-7B , embodiments of the present invention are directed toward a surgical screw  100 . In some embodiments, the surgical screw has a shaft  110 . In one embodiment, the shaft  110  has a threaded portion  120 . In certain embodiments, surgical screw  100  includes a head  140  disposed at a proximal end  130  of the shaft  110 . In one embodiment, the head  140  has a drive recess  150 . In one embodiment, the drive recess  150  is hexagonally shaped. Although illustrated as being hexagonally shaped, it is envisioned that the shape of the drive recess  150  may be configured in any manner suitable for distributing an insertion force throughout the screw, e.g., other polygonal or generally polygonal shapes, semi-circular, slotted, cross-recessed, torx star, or multiple round holes. 
     Referring to  FIG. 2B , the drive recess  150 , in certain embodiments, has a reservoir region  160  and a driver engagement region  170 . As seen by comparing  FIGS. 2B and 6B , in certain embodiments, the reservoir region  160  can be of varied shape and depth. The reservoir region  160  can be any region of the head  140  of the screw  100  that can be coated with a drug eluting component  200  in a manner that will not substantially impair a connection between a driver and the surgical screw  100  when the driver is operably disposed within the driver engagement region  170 . The driver engagement region  170  can be any region of the head  140  of the screw  100 , either coated or uncoated with the drug eluting component  200 , that is engageable with a driver when the driver is operably disposed within the head  140 . The reservoir region  160  and driver engagement region  170  need not be exclusive and may overlap. 
     In one embodiment, the reservoir region  160  defines a reservoir volume  210 , the drive recess  150  defines a driver recess volume  220  and the reservoir volume  210  is from about 10% to about 12% of the driver recess volume. In other embodiments, the reservoir volume  210  is about 8%, about 8.5%, about 9%, about 9.5%, about 10%, about 10.5%, about 11%, about 11.5%, about 12%, about 12.5%, about 13%, about 13.5%, about 14% or any range determinable from the preceding percents (for example, about 8% to about 9.5% or about 8.5% to about 13%) of the driver recess volume  220 . 
     In certain embodiments, multiple layers of drug eluting components can be layered into the reservoir region  160  of the drive recess  150  to allow for multiple therapeutic agents to be released at different rates, sequentially, or simultaneously in different concentrations. One of the layers may not contain a therapeutic agent, but serve as a barrier layer to inhibit diffusion of the drug. Exemplary materials which could act as a barrier layer include bioabsorbable polymers such as polycaprolactone or polyglycolide, natural fatty acids such as palmitic acid or stearic acid, and natural biopolymers such as collagen or alginate. 
     As shown in  FIG. 3B , in one embodiment, both a diffusion barrier layer  300  and a drug eluting component  200  are disposed within the reservoir region  160  of the drive recess  150 . 
     Further,  FIG. 4B  illustrates an exemplary view of the surgical screw where two drug eluting components, drug eluting component  200  and drug eluting component  400 , are disposed within the reservoir region  160  of the drive recess  150 . In some embodiments, drug eluting component  200  and drug eluting component  400  include different therapeutic agents. In other embodiments, the drug eluting component  200  and drug eluting component  400  are configured to elute a therapeutic agent at differing release rates. 
       FIG. 5B  shows an exemplary embodiment of the invention having a drug eluting component with a graded concentration  500 , e.g., a therapeutic agent being less concentrated at the surface and gradually more concentrated at deeper depths or, alternatively, a therapeutic agent being more concentrated at the surface and gradually less concentrated at deeper depths. 
     As shown generally in  FIG. 2B , one embodiment of the present invention includes a drug eluting component  200  disposed within the reservoir region  160  of the drive recess  150 . In certain embodiments, the drug eluting component  200  is positioned in a manner so that it does not substantially impair a connection between a driver and the surgical screw  100  when the driver is operably disposed within the driver engagement region  170 . For example, as shown in  FIG. 2B , the drug eluting component  200  may be positioned at the base  230  of the head  140 . In other embodiments, the reservoir region  160  of the drive recess  150  is adjacent to the driver engagement region  170  and the drug eluting component  200  does not extend into the driver engagement region  170 . 
     In one embodiment, the reservoir region  160  is shaped and dimensioned to retain the drug eluting component  200  when the drug eluting component  200  is in a cured condition. For example, as shown in  FIGS. 7A and 7B , the surgical screw  100  includes a lip  700  configured and dimensioned to retain the drug eluting component  200  when the drug eluting component  200  is in a cured condition. 
     In one embodiment, the drug eluting component  200  includes a carrier matrix containing a therapeutic agent. In certain embodiments, the carrier matrix includes a material that facilitates the release rate of the therapeutic agent into the body, e.g., a polymer, ceramic, or hydrogel. In one embodiment, the carrier matrix includes a bioabsorbable polymer, e.g., polycaprolactone, polylactic acid, polyglycolic acid, polyethylene glycol, or a combination thereof. 
     In other embodiments, the carrier matrix includes a soluble additive which dissolves at a controlled rate, generating pores through which the therapeutic agent can elute. Examples of a soluble additive would include polyethylene glycol, polyvinyl alcohol, glycerine, salts or water soluble crystalline solids. By varying the amount of soluble additive, the elution rate of the therapeutic agent may be modified. Certain embodiments having differing release rates, can be achieved by having multiple drug eluting components, each having differing bioabsorbable matrices having differing soluble additives. 
     In another embodiment, the carrier matrix includes a hydrophobic bioabsorbable polymer that contains a water swellable additive that swells with water after implantation into the body, allowing the therapeutic agent to be released at an increased rate. By varying the amount of water swellable additive, the elution rate of the therapeutic agent may be modified. 
     In one embodiment, the carrier matrix includes a nonabsorbable polymer, e.g., poly(methyl methacrylate). 
     In another embodiment, the carrier matrix includes a nonabsorbable polymer and a soluble additive, e.g., polyethylene glycol, polyvinyl alcohol, glycerine, salts or water soluble crystalline solids. The soluble additive dissolves at a controlled rate, generating pores in the nonabsorbable matrix through which a therapeutic agent can elute. 
     In certain embodiments, the carrier matrix includes a blend of bioabsorbable polymer and nonabsorbable polymer. 
     In other embodiments, the carrier matrix includes an erodible or biostable ceramic, e.g., silica, hydroxyapatite, calcium phosphate, bioglass, or a combination thereof. 
     In one embodiment, the carrier matrix includes a natural biopolymer, e.g., gelatin, alginates, chitosan, collagen or hyaluronate. 
     In one embodiment, the therapeutic agent includes an antibiotic or a combination of multiple antibiotics. In one embodiment, the therapeutic agent includes gentamicin. 
     In other embodiments, the therapeutic agent includes steroids, anti-inflammatory drugs, anti-proliferative compounds, antimycotic compounds, an antimitotic compounds, antimetabolite compounds, pain-relieving drugs, corticosteroids, angiostatic steroids, non-steroidal anti-inflammatory agents, and/or co-drugs. 
     In certain embodiments, the therapeutic agent includes a growth factor, e.g., bone morphogenetic protein 2 (BMP-2). In other embodiments, the therapeutic agent includes a local anesthetic, e.g., lidocaine. 
     The therapeutic agent, in certain embodiments, can either be dissolved completely into the material that facilitates its release into the body or remain as discrete particles within that material. 
     In one embodiment, the therapeutic agent constitutes at least about 20 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw  100 . In one embodiment, the therapeutic agent constitutes between about 20 wt % and about 60 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw  100 . In one embodiment, the therapeutic agent constitutes between about 20 wt % and about 40 wt % of the drug eluting component prior to any implantation of the drug eluting surgical screw  100 . In other embodiments, the therapeutic agent constitutes about 20 wt %, about 21 wt %, about 22 wt %, about 23 wt %, about 24 wt %, about 25 wt %, about 26 wt %, about 27 wt %, about 28 wt %, about 29 wt %, about 30 wt %, about 31 wt %, about 32 wt %, about 33 wt %, about 34 wt %, about 35 wt %, about 36 wt %, about 37 wt %, about 38 wt %, about 39 wt %, about 40 wt %, about 41 wt %, about 42 wt %, about 43 wt %, about 44 wt %, about 45 wt %, about 46 wt %, about 47 wt %, about 48 wt %, about 49 wt %, about 50 wt %, about 51 wt %, about 52 wt %, about 53 wt %, about 54 wt %, about 55 wt %, about 56 wt %, about 57 wt %, about 58 wt %, about 59 wt %, about 60 wt % or any range determinable from the preceding weight percents (for example, about 51 wt % to about 55 wt % or about 30 wt % to about 52 wt %) of the drug eluting component prior to any implantation of the drug eluting surgical screw  100 . 
     In one embodiment, the drug eluting component  200  is configured to elute at least about 80% of the therapeutic agent over a three day period starting from when the drug eluting surgical screw  100  is implanted into the animal. In other embodiments, the drug eluting component  200  is configured to elute about 50%, about 51%, about 52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%, about 60%, about 61%, about 62%, about 63%, about 64%, about 65%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%, about 73%, about 74%, about 75%, about 76%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 97%, about 98%, about 99%, about 100% or any range determinable from the preceding percents (for example, about 50% to about 77% or about 85% to about 94%) of the therapeutic agent over a one day, two day, three day, four day, five day, six day, seven day or any range determinable from the preceding days (for example, 1-3 days or 3-4 days) period starting from when the drug eluting surgical screw  100  is implanted into the animal. 
     In one embodiment, the present invention includes a method of manufacturing a drug eluting surgical screw  100 . In one embodiment, the method includes forming a film derived from a drug eluting component. In one embodiment, a film is formed by mixing a drug eluting component with a solvent to form a solution and heating the solution to evaporate the solvent and form a film. In another embodiment, a film is formed by subjecting a drug eluting component to a melting process, e.g., by a process including compounding, and then subjecting the melted drug eluting component to extrusion or compression molding. In one embodiment, after the film has been formed, the method includes, configuring at least a portion of the film to a size and shape that complements a drive recess of a surgical screw. In one embodiment, the method further includes placing the at least a portion of the film into the drive recess  150  of the surgical screw  100 . In one embodiment, after placing the at least a portion of the film into the drive recess  150 , heating the at least a portion of the film to conform to the size and shape of a cross-section of the drive recess. In one embodiment, after heating the at least a portion of the film, the method includes, pressing the at least a portion of the heated film into the drive recess  150 . In one embodiment, a forming tool, e.g., a screwdriver with an end shaped to fit within the drive recess, is used, e.g., used by pressing the heated film into the drive recess  150 , to form a sufficient bond between the at least a portion of the heated film and the drive recess side walls. 
     In one embodiment, the method of manufacturing a drug eluting surgical screw  100  described above is repeated to create a drug eluting surgical screw  100  having multiple layers of drug eluting components, e.g., as shown in  FIGS. 4A and 4B . 
     Referring to  FIG. 8 , in one embodiment (shown schematically), the present invention includes a method of using the drug eluting surgical screw  100  to secure an implant  11 , e.g., a fixation plate. In one embodiment, the method includes forming a cavity  65  in a bone  55  for receiving the drug eluting screw  100 , e.g., via drilling. The method further may include placing an implant  11  having an aperture  21  against the bone  55 , the aperture  21  being aligned with the cavity  65 . The method further may include using a driver to fix the drug eluting screw  100  to the bone  55 , whereby the implant  11  is held between the bone  55  and the head  140  of the screw. 
     Still referring to  FIG. 8 , in one embodiment the present invention includes a method of reducing the risk of infection following surgery. In one embodiment, the method includes using the drug eluting surgical screw  100  to secure an implant  11  in an animal following surgery. In certain embodiments, the drug eluting component  200  will elute an antibiotic, e.g., gentamicin, locally at the surface of the implant  11  thereby reducing the risk of infection. 
     It will be appreciated by those skilled in the art that changes could be made to the exemplary embodiments shown and described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the exemplary embodiments shown and described, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the claims. For example, specific features of the exemplary embodiments may or may not be part of the claimed invention and features of the disclosed embodiments may be combined. 
     It is to be understood that at least some of the figures and descriptions of the invention have been simplified to focus on elements that are relevant for a clear understanding of the invention, while eliminating, for purposes of clarity, other elements that those of ordinary skill in the art will appreciate may also comprise a portion of the invention. However, because such elements are well known in the art, and because they do not necessarily facilitate a better understanding of the invention, a description of such elements is not provided herein. 
     Further, to the extent that the method does not rely on the particular order of steps set forth herein, the particular order of the steps should not be construed as limitation on the claims. The claims directed to the method of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the steps may be varied and still remain within the spirit and scope of the present invention.