Abstract:
A needle-less injector system having an ampule with an elongated hollow body. The elongated hollow body includes a nozzle and an aperture for receiving a plunger. The aperture extends from the second end of the body towards the first end and is in fluid communication with the nozzle. The ampule cooperates with a plunger that has a concave rib that extends about the perimeter of the plunger and towards the first end of the plunger. As the plunger moves through the aperture the concave rib sealingly engages the sidewalls of the aperture.

Description:
RELATED APPLICATION  
       [0001]     This is a continuation of U.S. patent application Ser. No. 10/158,853, entitled “Needleless Injector and Ampule System,” filed on May 30, 2002. The present application also relates to U.S. patent application Ser. No. 11/121,439, entitled “Needleless Injector,” filed May 3, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a system for the subcutaneous delivery of medicaments, and more particularly to a hand held actuator, and a plunger and ampule or vial used to deliver a stream of medication.  
         [0004]     2. Description of Related Art  
         [0005]     The need for a needle-less injection device that can be used to deliver a fine, high-pressure stream of medication through the skin has been recognized for some time. However, the problems associated with creating this high-pressure stream, particularly with a self-contained, hand-held device, has proven to be a greater challenge than expected. The typical approach at creating these streams has been to use a piston that is driven by a CO2 cartridge, compressed air, or a spring. The piston is then used to drive the medicament from a reservoir through a small nozzle that is used to create the fine stream that is to penetrate the skin. The size and energy of the stream allows the stream to penetrate the skin to a depth where it can then be absorbed by the body.  
         [0006]     One important problem is that in order to create such a stream it is difficult to produce a nozzle that provides a tight, uniform stream, and not a spray of the medicament.  
         [0007]     Another important problem associated with the design of a needle-less injection system involves the efficient delivery of the dose of medicament held within the reservoir. In other words, it is important that the system does not allow medicament to escape between the piston and the reservoir or cylinder through which the medicament is being delivered. The problem of loss of medicament is typically caused by the escape of medicament under the pressure required to adequately deliver the medicament through the nozzle.  
         [0008]     Still another important problem associated with needle-less injection devices, and particularly with hand-held devices of this type, is the provision of sufficient power to create and deliver a stream with sufficient energy so that the stream can penetrate the body to a depth where the medicament can be absorbed.  
         [0009]     Yet another problem associated with needle-less devices is maintenance of a required amount of pressure during the delivery of the medicament from the reservoir, through the nozzle.  
       SUMMARY OF THE INVENTION  
       [0010]     One object of the present invention is to provide a needleless injection device that delivers a fine, high pressure stream of medicament through a surface.  
         [0011]     Another object of the present invention is to provide a needleless injection system that delivers the medicament without any loss of quantity thereof.  
         [0012]     In accomplishing these and other objects of the present invention, there is provided a needleless injection device including an ampule. The ampule includes an elongated hollow body, the elongated hollow body having a first end and a second end. The first end of the hollow body includes a nozzle, and the second end of the hollow body including an aperture for accepting a plunger. The aperture extends from the second end towards the first end and is in fluid communication with the nozzle. The generally cylindrical plunger, includes a first end and a second end. The plunger also includes a concave rib extending about the perimeter of the plunger and extending towards the first end.  
         [0013]     According to one example of the invention, the body of the plunger is centered about an axis and the first end of the plunger includes a generally conical end that is centered about the axis. Additionally, the conical end will extend from the concave portion of the concave rib. Still further, it is contemplated that the plunger will include a second rib, the second rib being between the concave rib and the second end of the plunger.  
         [0014]     The plunger is received by the aperture in the ampule, with the concave rib sealingly engaging the sidewalls of the aperture in the body of the ampule. The second rib will also cooperate with the sidewalls of the aperture of the ampule and may provide some sealing function, but will primarily serve to stabilize or align the plunger as it is forced through the ampule.  
         [0015]     The ampule connects to an actuator that will provide the power to push the plunger through the ampule and drive the medicament from the ampule through the nozzle. In an illustrated example of the actuator, the actuator includes a casing that holds a spring that is used to drive a rod. The rod in-turn pushes against the plunger, which then pushes the medicament through the ampule.  
         [0016]     The release of the spring in the actuator is accomplished by providing a hammer that includes a forward end that is adapted for cooperating with the rod and the trigger mechanism, and an aft end that is adapted for cooperating with the spring. The trigger mechanism is used to retain the spring in a loaded or compressed position, and then release the spring to drive the plunger through the ampule.  
         [0017]     These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiment relative to the accompanied drawings, in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a cross-sectional plan view of the system of the present invention in a cocked position.  
         [0019]      FIG. 2  is a cross-sectional view of the system of the present invention in a fired position.  
         [0020]      FIG. 3  is a partial cross-sectional view of the device of the present invention illustrating the cooperation of the hammer, push-rod, vial or ampule, and seal.  
         [0021]      FIG. 4  is an enlarged cross-sectional view of the components of  FIG. 3 .  
         [0022]      FIG. 5  is an enlarged cross-sectional view of the seal or plunger of the device of the present invention as it is driven through the vial or ampule.  
         [0023]      FIG. 6  is a cross-sectional view illustrating the cooperation of the plunger and ampule of the present invention at the end of the stroke or delivery cycle.  
         [0024]      FIG. 7  is a side view of the hammer of the device of the present invention mounted between the spring and the push-rod.  
         [0025]      FIG. 8  is an end view of the hammer of  FIG. 7 .  
         [0026]      FIG. 9  is a cross-sectional view taken along line  9 - 9  of  FIG. 7 .  
         [0027]      FIG. 10  is an end view of an embodiment of the plunger of the device of the present invention.  
         [0028]      FIG. 11  is a cross-sectional view of the plunger.  
         [0029]      FIG. 12  is a perspective view of the plunger of the device of the present invention.  
         [0030]      FIG. 13  is a cross-sectional view of the vial or ampule of the device of the present invention.  
         [0031]      FIG. 14  is an end view of the vial or ampule of the device of the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0032]     Referring to  FIG. 1 , a needle-less injection system  10  is shown in a cocked position with the cover of the actuator removed along with sections of the internal sleeve, so that the internal components may be observed. It should be understood that it is contemplated that the system of the present invention may be used with a hand held actuator  12  or other actuator, for example, using a pneumatic piston or combustion driven piston. Actuator  12  includes a hammer  14  that slides along a sleeve  16 . The hammer  14  is powered by a spring  18  that is held within the sleeve  16 . The power or driving force provided by the spring  18  may be fixed by creating a device that will allow the spring  18  to be compressed a set distance or by providing a spring compression adjustment mechanism  20 , such as a threaded plug  22  that is mounted on an end of the sleeve  16 .  
         [0033]     As shown in  FIGS. 1 and 2 , energy is stored in the spring  18  by compressing the spring  18  to the “cocked position” illustrated in  FIG. 1 . This energy is then released to the hammer  14 , which drives a rod  24  that extends between the hammer  14  and a plunger  26 . The plunger  26  fits into and seals an aperture  28  in an ampule  30 . The ampule  30  is attached to the actuator  12  by way of a bayonet connector  32  ( FIG. 6 ), or a threaded or any other suitable connector.  
         [0034]     Referring to  FIGS. 2-6 , it will be understood that the disclosed system will deliver medicament through the skin by creating a very thin, high energy or velocity, jet of medicament  34  through the ampule  30 . The jet of medicament  34  is produced by driving the plunger  26  through the aperture  28  or open end  48  to pressurize the fluid medicament  36  in the ampule  30 , which pushes the medicament  36  through a nozzle  38  located on second end  50  of the ampule  30 .  
         [0035]     It should be appreciated that the ampule  30  will be made from a readily moldable material, such as a pharmaceutical grade polypropylene material that is suitable for injection molding or any other polymer that is suitable for injection molding. An important drawback to the use of polymers as the material for the ampule  30  is that the mechanical properties of these materials allow the materials to deflect under the pressures needed for creating the jet of medicament  34  through the nozzle  38 . Additionally, fabrication of the ampule  30  from stiffer materials results in a device that is too brittle or a device that cannot be manufactured through the use of high production rate methods, such as injection molding. Therefore, the machining of the ampules from stainless steel would be a prohibitively expensive approach at manufacturing the device. Furthermore, an opaque material will not allow the user of the device to ascertain whether the plunger  26  has traveled through the desired length of the ampule  30 , and delivered the adequate dosage of medicament.  
         [0036]      FIGS. 3-6  illustrate the entire travel of the plunger  26  as driven by the spring  18  and hammer  14 . Importantly,  FIGS. 4 and 5  illustrate the deflection of the sidewalls of the vial or ampule while the plunger or seal is driven towards the nozzle to force the medicament from the ampule. The deflection  42  of the ampule  30  that has been produced by the pressurization of the ampule  30  during travel of the plunger  26  through the ampule  30  is shown by dashed line. In known devices, this deflection  42  causes a loss of pressure in the ampule  30 , which results in an inadequate transfer of energy to the jet of medicament  34 . However, plunger  26  of the present invention includes a concave rib  44  that is designed to open towards the nozzle  30 . The concave rib  44  should be made of a flexible, yet strong material, such as polypropylene, rubber or other polymer. As shown in  FIG. 5 , the plunger deflects to compensate for the dimensional changes in the ampule.  
         [0037]     In operation, as illustrated in  FIGS. 3-6 , the plunger  26  is driven through the aperture  28  by the force of the spring  18  pushing against the hammer  14 . As the plunger  26  is driven through the elongated hollow body  46  of the ampule  30 , the plunger  26  pushes the medicament  36  from the ampule  30  and through the nozzle  38 . The elongated hollow body  46  of the ampule  30  include a first end  40  and a second end  50 . Thus, the plunger  26  is pushed through the aperture  28 , from the first end  40  towards the second end  50  of the amplule  30 . The pressure within the aperture  28  of the ampule  30  increase as the plunger  26  is pressed against the medicament  36 , causing the deflection  42  of the ampule  30 . In order to maintain the pressure, and hence the required energy transfer to produce the jet of medicament  34 , the concave rib  44  also expands under the pressure, as indicated by the arrows  52  in  FIG. 5 . The expansion or flaring out of the concave rib  44  takes up or seals any fluid passages or bypasses that may be otherwise formed due to the expansion of the amplule  30 .  
         [0038]     Thus, from the accompanying illustrations, it will be understood that the plunger  26  extends about an axis  54  and may also include a first end  56  ( FIG. 11 ) that terminates in a generally conical surface  58 . Additionally, the plunger  26  includes a second end  60  and a mid-portion  61 , located between the first end  56  and the second end  60 . Plunger  26  also includes an external surface  62  that may be cylindrical or of any other suitable cross-section. The concave rib  44  extends about the axis  54 , and expands towards the first end  56  of the plunger  26 . In the illustrated example, the concave rib  44  extends over the conical surface  58  of the plunger and towards the first end  56  of the plunger  26 . Still further, in the illustrated example, the concave rib  44  extends over a portion of the conical surface  58 . The conical surface  58  cooperates with the nozzle  38  to push any remaining medicaments from ampule  30 .  
         [0039]     Referring to  FIGS. 10-12 , it will be understood that plunger  26  may also include a second rib  64 . The second rib  64  is positioned between the concave rib  44  and the second end  60  of the plunger  26 . The second rib  64  cooperates with the concave rib  44  to stabilize the plunger  26  as it is driven through the ampule  30 . The design of the concave rib  44  has been illustrated as being approximately conical in shape. This conical shape provides flexibility that allows the second rib  64  to accommodate the shape of the sidewalls  66  of the aperture  28 . However, it is contemplated that the shape or cross-section of the second rib  64  may be one of many different shapes, and may not act as a seal, meaning that the rib is not continuous about the exterior surface of the body of the plunger  26 .  
         [0040]      FIGS. 13 and 14  provide greater detail of the ampule  30 , and illustrate that it is contemplated that the nozzle  38  can be located within a raised annular portion  68 , which in turn is located within a recessed annular portion  70 . The recessed annular portion  70  cooperates with the raised annular portion to pull the skin tight, and retain this tightness, around the nozzle opening  72 , so that the nozzle opening  72  is at a distance from the skin and the skin that is to be injected is pulled taut so as to avoid energy losses in the jet of medicament as the jet of medicament impacts the skin. In other words, by pulling the skin taut, one minimizes energy losses due to deflection of the skin. Still further, the bayonet connectors  32  are clearly visible from these figures, together with radially positioned stiffeners  74 .  
         [0041]     Although the present invention has been described in relation to particular embodiments thereof, many other variations and other uses will become apparent to those skilled in the art. It is preferred therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.