Abstract:
An improved method and apparatus for administering drugs during an endoluminal procedure is disclosed. An embodiment of the present invention utilizes a catheter having distal and proximal ends and a drug reservoir located within the catheter to efficiently and accurately deliver drugs during an endoluminal procedure.

Description:
FIELD OF THE INVENTION 
   This invention generally relates to endoluminal procedures. More specifically it relates to an improved method and apparatus for providing accurate, easy to administer, minimum waste delivery of therapeutic drugs while performing endoluminal procedures. 
   BACKGROUND 
   An endoluminal procedure is a medical procedure that takes place in one of the many lumens within the human body. An endoluminal procedure may take place in vascular, gastrointestinal, or air exchange lumens, and may involve disease diagnosis, or treatment, or both. Millions of endoluminal procedures are performed each year in hospitals around the world. 
   Endoluminal procedures are often performed utilizing a device known as an endoscope. With reference to  FIG. 1 , an endoscope  140  is a tube, either rigid or flexible, which is introduced into the body lumen  180  through an opening in the human body  185 , such as the mouth or rectum. The endoscope may simply be used to hold open the lumen for examination or it can and usually will contain an open or “working” channel  130  into which the Endoscopist will insert and withdraw a myriad of endoluminal devices. Lights, visionary systems, and other devices may be incorporated into or used in conjunction with the endoscope to assist in completing the endoluminal procedure. 
   A treatment device that is commonly used during the completion of endoluminal procedures is a catheter. As illustrated in  FIG. 1 , the catheter  170  is essentially a flexible hollow tube. Often the catheter is fitted with a hypodermic needle  120  fitted to its distal end for the injection of therapeutic or diagnostic agents. In certain applications, where therapeutic drugs are to be passed into the body lumen  180 , the catheter  170  will accept, or be manufactured with, a syringe  150  at its proximal end. The syringe  150  can be pre-filled with a therapeutic drug  195  or it can be filled at some other time, for example, contemporaneous with the endoluminal procedure being performed. 
   The endoscope  140  will be positioned to allow access to the treatment area  110 . Then, as required, the Endoscopist will position the distal end of the catheter through the endoscope into the treatment area  110 . The positioning of the catheter is often a difficult and time-consuming process as it must be done by the Endoscopist from the proximal end of the endoscope, which may be a hundred or more centimeters from the treatment area. Once the catheter is positioned drugs can be administered or some other procedure can be performed. Administering the drugs can be an arduous task due to the tremendous pressure required to be applied to the handle  165  to force the drug out of the syringe  150 , through the entire length of the catheter  170  and ultimately out the hypodermic needle  120 . This is particularly true when the therapeutic drug to be administered is highly viscous. 
   This method is highly inefficient as the entire internal channel  190  of the catheter  170  must be filled with the drug before even a small amount can be forced into the treatment area  110 . Moreover, since the entire internal channel  190  of the catheter  170  will be filled with the drug, a large amount of the drug is simply disposed of, along with the catheter, at the completion of the procedure. This unwanted disposal of therapeutic drugs can be expensive and can add significant cost to the procedure. 
   Thus, it would be desirable to provide an apparatus that can accurately deliver a therapeutic drug to an endoluminal treatment site both efficiently and with a minimum of effort and waste. 
   SUMMARY OF THE INVENTION 
   The present invention is an improved method and apparatus for administering drugs during an endoluminal procedure that includes a catheter having a distal end and a proximal end and a drug reservoir located within the catheter to efficiently and accurately deliver drugs during an endoluminal procedure. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a known drug delivery device wherein the drug reservoir is located at the proximal end of the catheter. 
       FIG. 2  illustrates a catheter, in accordance with an embodiment of the present invention, as it would appear having been introduced into a lumen of the body through the working channel of an endoscope. 
       FIG. 3  illustrates the distal end of the catheter of  FIG. 2  in accordance with an embodiment of the present invention. 
       FIG. 4  illustrates the embodiment of  FIG. 3  without an encasing endoscope or catheter. 
       FIG. 5  illustrates an alternative embodiment, without an encasing catheter or endoscope, that utilizes a cable assembly to assist in the delivery of the drug in accordance with the present invention. 
       FIG. 6A  illustrates an alternative embodiment, without an encasing catheter or endoscope, that utilizes compressed gas to assist in the delivery of the drug in accordance with the present invention. 
       FIG. 6B  illustrates an alternative embodiment, without an encasing catheter or endoscope, that utilizes two reactive chemicals to generate the compressed gas that assists in the delivery of the drug in accordance with the present invention. 
       FIG. 7  illustrates an alternative embodiment of  FIG. 6A  wherein an injection nozzle, instead of a hypodermic needle, is utilized to administer the drug. 
       FIG. 8  illustrates an alternative embodiment of  FIG. 7  that employs multiple drug reservoirs manifolded together to a single injection nozzle. 
   

   DETAILED DESCRIPTION 
   The instant invention provides for an efficient and effective method and apparatus for delivering therapeutic drugs to an endoluminal cavity.  FIG. 2  illustrates an embodiment of the drug delivery device  260 . As can be seen, the drug delivery device  260  is comprised of a hypodermic needle  120 , a connection tube  200 , a drug reservoir  230 , a flexible catheter  170 , an activation line  210 , an activation mechanism  280 , and an activation mechanism switch  220 . The hypodermic needle  120  is rigidly connected to one end of the hollow connection tube  200  and is in fluid communication with the connection tube channel  290  of the hollow connection tube  200 . The hollow connection tube  200  is a rigid member capable of withstanding the bending and kinking forces generated during the insertion, manipulation, and use of the drug delivery device  260  and is generally less than one centimeter in length. The hollow connection tube  200  is rigidly and sealably connected to the cylindrically shaped drug reservoir  230 . The exit orifice  270  of the drug reservoir  230  is aligned with, and in fluid communication with, the connection tube channel  290 . An activation mechanism  280  is rigidly connected to the proximal end of the drug reservoir  230  and is in communication with the drugs  195  present in drug reservoir  230 . The activation mechanism  280  generates the compressive force necessary to eject drugs  195  from the drug reservoir  230  through the exit orifice  270 , through the connection tube channel  290 , and out the hypodermic needle  120 . The activation mechanism is connected to a wire  210  which is connected to an activation mechanism control switch  220 . The activation mechanism control switch  220  is operated by the Endoscopist and turns the activation mechanism  280  on and off. 
   The drug  195  in  FIG. 2  can be pre-loaded by the drug manufacturer into the drug reservoir  230  or can be loaded by the Endoscopist at a time contemporaneous with the procedure. To fill the drug reservoir  230 , the Endoscopist would load the drug  195  into the drug reservoir  230  by unscrewing the drug reservoir  230  from the distal end of the catheter  170 , filling the drug reservoir  230  with a desired dose of drug  195  through the exit orifice  270  and rescrewing the drug reservoir  230  back into the distal end of the catheter  170 . 
   The drug agents used in the present invention include, for example: pharmaceutically active compounds, biologically active solutions, proteins, oligonucleotides, genes, DNA compacting agents, gene/vector systems (i.e., anything that allows for or enhances the uptake and expression of nucleic acids), nucleic acids (including, for example, DNA, cDNA, RNA, antisense DNA or RNA), cells (autologous, allogenic, or xenogeneic), and liposomes and cationic polymers that are selected from a number of types depending on the desired application. Examples of the biologically active solutes include: anti-thrombogenic agents such as heparin, heparin derivatives, urokinase, and PPack (dextrophenylalanine proline arginine chloromethylketone); anti-proliferative agents such as paclitaxel, enoxaprin, angiopeptin, or monoclonal antibodies capable of blocking smooth muscle cell proliferation, hirudin, and acetylsalicylic acid; anti-inflammatory agents such as dexamethasone, prednisolone, corticosterone, budesonide, estrogen, sulfasalazine, and mesalamine; antineoplastic/antiproliferative/anti-miotic agents such as paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine, epothilones, endostatin, angiostatin and thymidine kinase inhibitors; anesthetic agents such as lidocaine, bupivacaine, and ropivacaine; anti-coagulants such as D-Phe-Pro-Arg chloromethyl keton, an RGD peptide-containing compound, heparin, antithrombin compounds, platelet receptor antagonists, anti-thrombin anticodies, anti-platelet receptor antibodies, aspirin, protaglandin inhibitors, platelet inhibitors and tick antiplatelet peptides; vascular cell growth promotors such as growth factor inhibitors, growth factor receptor antagonists, transcriptional activators, and translational promotors; vascular cell growth inhibitors such as growth factor inhibitors, growth factor receptor antagonists, transcriptional repressors, translational repressors, replication inhibitors, inhibitory antibodies, antibodies directed against growth factors, bifunctional molecules consisting of a growth factor and a cytotoxin, bifunctional molecules consisting of an antibody and a cytotoxin; cholesterol-lowering agents; vasodilating agents; and agents which interfere with endogeneus vascoactive mechanisms. 
   In practicing the invention embodied in  FIG. 2  the Endoscopist inserts the endoscope  140  into the patient&#39;s body  185  through the opening in the patient&#39;s body  185  until the distal end of the endoscope  140  provides access to the lumen  180  to be treated. The distal end of the drug delivery device  260 , loaded with the requisite drug  195 , is then guided by the Endoscopist towards the distal end of the endoscope  140  until the hypodermic needle  120  of the drug delivery device  260  reaches the treatment area  110  of the lumen  180 . Navigation aides, common in the art, such as lights and optical cameras, typically provided by the endoscope, may be used to aid in the positioning of the distal end of the drug delivery device  260 . Once properly positioned, the Endoscopist will engage the activation control mechanism  220  thereby sending a signal through the wire  210  to the activation mechanism  280  to instruct the activation mechanism  280  to urge the drug  195 , present in the drug reservoir  230 , through the hypodermic needle  120 , and into the treatment area  110 . 
   Once the drug  195  has been administered into the treatment area  110 , the Endoscopist retracts the drug delivery device  260  from the endoscope  140  and discards the drug delivery device  260 . 
   The activation mechanism  280  may have numerous alternative embodiments as will be evident to those of skill in the art. For example, an electric motor, a cable assembly, or compressed gas could be employed, in conjunction with a moveable face of the drug reservoir  230 , to generate the force necessary to urge the drug  195  from the drug reservoir  230  during the procedure. Alternatively, a collapsible drug reservoir can be employed wherein the compressed gas is used to collapse or implode the drug reservoir  230  in order to squeeze the drug  195  from it as the volume of the drug reservoir  230  decreases. 
   In addition, a specific dosage of a drug can be administered through this process. For example, the Endoscopist can unscrew the drug reservoir  230  from the distal end of the catheter  170  before the procedure begins and load a specific dosage of a drug  195  into the drug reservoir  230  in order to completely expel it during the procedure. Alternatively, the specific dosage could be pre-measured by the manufacturer and then loaded into the drug reservoir  230  by the manufacturer. Moreover, the activation mechanism  280  could be calibrated in order to eject a predetermined drug dosage from the drug chamber each time the activation mechanism  280  is engaged. 
     FIG. 3  illustrates an alternative embodiment of a device that can be employed when practicing the present invention.  FIG. 3  is an enlarged view of the distal end of the catheter  170 . In  FIG. 3  the activation mechanism  280  comprises an electric motor  300  having a rotating shaft  340 , a gear  360 , a connecting member  320 , a piston  310 , and motor control wires  330 . As can be seen, the piston  310  comprises one wall of the cylindrically shaped drug reservoir  230  that is designed to slide within the drug reservoir  230  in order to push the drug  195  through the exit orifice  270  of the drug reservoir  230 . The piston  310  is pushed by the connecting member  320 . The connecting member  320  is rigid and pole-like with screw threads  370  etched into its outer surface. The electric motor shaft  340  is in contact with a gear  360  that is in communication with the screw threads  370  of the connecting member  320  and causes the connecting member  320  to push the piston  310  towards the drug  195  in the drug reservoir  230  when the electric motor  300  is in operation. The greater the number of rotations completed by the electric motor  300  the greater the distance the piston  310  will travel and the greater the volume of drug  195  will be forced from the drug reservoir  230  and out the hypodermic needle  120 . 
   The electric motor  300  in  FIG. 3  is activated by the Endoscopist from the proximal end of the drug delivery device  260 . As required, the Endoscopist will energize the motor control wires  330  by depressing the activation mechanism control switch  220  which contains both a depressable on and off button and a common 1.5 volt dc power source such a Duracell® MS76 silver oxide battery or an Energizer® 357 watch battery. Once activated, the electric motor  300  in  FIG. 3  will rotate, ultimately pushing the piston  310  forward into the drug reservoir  230 . 
     FIG. 4  provides an enlarged view of the distal end of the embodiment depicted in  FIG. 3  without the endoscope  140  or the encasing catheter  170 . As is evident and as was illustrated in  FIG. 3 , the electric motor  300  has a motor shaft  340  that is in direct rotational communication with a gear  360  that is in direct rotational communication with the screw threads  370  of the connecting member  320 . As the electric motor  300  turns it rotates the motor shaft drive  340  that turns the gear  360  which is inscribed with teeth  365  that meet with and advance the screw threads  370  thereby rotating and advancing the connecting member  320 . As in  FIG. 3 , the connecting member  320  advances and pushes the piston  310  further into the drug reservoir  230  thereby forcing any drug  195  present in the drug reservoir  230  out the exit orifice  270 , through the connection tube  200 , and out the hypodermic needle  120 . 
   Alternatively, instead of using the electric motor assembly described above, a cable assembly system could be used to force the drug  195  from the drug reservoir  230 .  FIG. 5 , which provides an enlarged view of the distal end of the present invention, without the encasing endoscope or catheter, employs such a cable assembly system  500 . The cable assembly system shown in  FIG. 5  contains a piston  310 , a connecting member  320  perpendicularly affixed to the piston  310 , a first pulley  520 , rotatably attached to the end opposite the piston  310  of the connecting member  320 , a second pulley  510 , rotatably connected to a support bar  550  that is rigidly connected to the drug reservoir  230 , and a cable  540 . The cable assembly system, as is evident, also contains a cable  540 . One end of the cable  540  is attached to the center of the second pulley  510  with the other end being free and accessible at the proximal end of the drug delivery device. The cable  540  loops around the first pulley  520 , around the second pulley  510  and then extends though the drug delivery device  260  until the cable&#39;s other end emerges at the device&#39;s proximal end for use by the Endoscopist. 
   As required, the Endoscopist will pull on the loose available end of the cable  540  in order to inject the drugs into the luminal area to be treated. In operation, when the cable  540  is pulled the first pulley  520  is drawn towards the second pulley  510 . Being coupled to the connecting member  320 , the first pulley  520  moves the connecting member  320  along with it. As the first pulley  520  moves closer to the second pulley  510 , which is rotatably mounted to the support member  550 , the connecting member  320  and the piston  310 , connected to the first pulley  520 , will also move the same distance. As the piston  310  moves, the drug  195  present in the drug reservoir  230  is urged therefrom and is ultimately forced out the hypodermic needle into the luminal area to be treated. As is evident the cable can be pulled at various rates of speed and for various predetermined distances in order to control the dosage delivered. Therefore, in practice, the Endoscopist can administer a portion of the drugs present in the drug reservoir or can displace the entire volume of the drug reservoir by varying the length of cable  540  that the Endoscopist pulls from the working end of the drug delivery device  260 . 
     FIG. 6A  is a view of the distal end of another embodiment of the present invention absent the encompassing catheter  170  and the endoscope  140 . In this embodiment compressed gas is utilized to move piston  310  instead of an electric motor or cable assembly system. The compressed gas  610  is located within a compressed gas chamber  630  proximate to the piston  310  of the drug reservoir  230  and is used to generate the compressive force required to push the piston  310  against the drug  195  and to force the drug  195  through the exit orifice  270 . The compressed gas  610  may be pre-loaded into the compressed gas chamber  630  before the entire drug delivery device  260  is inserted into the patient. Various methods of loading the compressed gas  610  into the compressed gas chamber  630  will be readily apparent to one of skill in the art and can include pre-loading both the compressed gas  610  and the drug  195  before the procedure is performed at the manufacturing facility, and loading the compressed gas  610  into the compressed gas chamber  630  through a charging orifice  650  contemporaneous with the performance of the procedure. 
   Alternatively, as can be seen in  FIG. 6B , instead of loading compressed gas into compressed gas chamber  610  the compressed gas chamber may be divided by a removable partition  660  that separates two reactive chemicals  670  which, when combined, react to create an innocuous compressed gas. Therefore, in practice, before the beginning of the procedure, the Endoscopist will remove the removable partition  660 , from the compressed gas chamber, exposing the reactant chemicals to each other and causing them to react and generate the compressed gas that will be required to eject the drug  195  from the drug reservoir  230 . 
   To prevent the undesired discharge of the drug  195  once the compressed gas chamber is charged a micro-valve  600  is inserted into the connection tube  200 . This micro-valve  600  is opened and closed by depressing a plunger  640  located at the proximal end of the drug delivery device  260  on the proximal end of the valve control line  620 , outside the patient&#39;s body. The valve control line  620  is in communication with the micro-valve  600 . When the plunger  640  is depressed it pushes a cable  660 , located within the valve control line  620  that slides the micro-valve  600  open. When the micro-valve  600  is opened the drug  195 , under pressure from the compressed gas  510 , can now flow and travel through the micro-valve  600  and out the hypodermic needle  120 . Thus, as required during the procedure, the Endoscopist will depress the plunger  640 , which opens the micro-valve  600  and permits the compressed gas  610  to push the piston  310  against the drug  195  in order to urge the drug out of the reservoir and ultimately into the treatment area. 
   In an alternative embodiment of the device in  FIG. 6A , the drug reservoir  230  is, instead, manufactured as a reconfigurable chamber. Made from a flexible membrane, in lieu of the rigid material depicted above, the reconfigurable chamber collapses from the compressive loads of the compressed gas during use. Rather than pushing the piston  310  to force the drug  195  from the drug reservoir  230  the compressed gas  610  would act upon the reconfigurable drug reservoir  230  to collapse it and squeeze the drugs from it once the micro-valve  600  is opened. 
     FIG. 7  is an alternative embodiment of  FIG. 6A  illustrating an injection nozzle  700  being employed for injecting drugs  195  into the treatment area  110  in lieu of a hypodermic needle  120 . The injection nozzle, as is known to one of skill in the art, drives the drug into the tissue. 
     FIG. 8  illustrates an alternative embodiment of the present invention which employs a plurality of N drug reservoirs at the distal end of the drug delivery device and an injection nozzle  700 . As is evident several drug reservoirs  230  and  810  numbered  1  . . . N are connected to a manifold  820  with N input ports  830  and one output port  740 . The output port  740  of the manifold  820  is connected to the injection nozzle  700 . Different drugs can be loaded into each of the drug reservoirs to be injected one at a time or in different combinations into the manifold  820  and out the injection nozzle  700  of the drug delivery device. Alternatively, the same drug can be placed within each of the drug reservoirs to increase the dosage available for the procedure. Also visible in  FIG. 8  are microvalves  600 , hollow connection tubes  200 , injecting drugs  195  within drug reservoir  230 , and pistons  310 . 
   As described above, an endoluminal drug delivery method device is provided. The disclosed embodiments are illustrative of the various ways in which the present invention may be practiced. Other embodiments can be implemented by those skilled in the art without departing from the spirit and scope of the present invention.