Patent Publication Number: US-2011071492-A1

Title: Hub assembly having a hidden needle for a drug delivery pen

Description:
FIELD OF THE INVENTION 
     The present invention relates to a hidden needle for a pen injection device. More particularly, the present invention relates to a compressible member connected to a hub of the pen injection device that covers the needle to prevent a patient from seeing the needle, and compresses to expose the needle during the injection. 
     BACKGROUND OF THE INVENTION 
     Medication delivery pens are hypodermic syringes used for self-injection of precisely measured doses of medication. Pens are widely used, for example, by diabetics to dispense insulin. 
     A typical prior art medication delivery pen includes a cartridge that contains a volume of liquid medication sufficient for several doses. The dose is into a tissue area, such as the intramuscular tissue layer, the subcutaneous tissue layer, or the intradermal tissue layer. 
     The assembly and operation of a typical pen injection device, as shown in  FIGS. 1 and 2 , is described in U.S. Patent Application Publication No. 2006/0229562, published on Oct. 12, 2006, which is hereby incorporated by reference in its entirety. 
     Pen injection devices, such as the exemplary pen injector  100 , as shown in  FIGS. 1 and 2 , typically comprise a dose knob/button  24 , an outer sleeve  13 , and a cap  21 . The dose knob/button  24  allows a user to set the dosage of medication to be injected. The outer sleeve  13  is gripped by the user when injecting medication. The cap  21  is used by the user to securely hold the pen injector device  100  in a shirt pocket, purse or other suitable location. 
       FIG. 2  is an exploded view of an exemplary drug delivery pen shown in  FIG. 1 . The dose knob/button  24  has a dual purpose and is used to both set the dosage of the medication to be injected and to inject the dosed medicament via the lead screw  7  and stopper  15  through the medicament cartridge  12 , which is attached to the drug delivery pen through a lower housing  17 . In standard drug delivery pens, the dosing and delivery mechanisms are all found within the outer sleeve  13  and are not described in greater detail here as they are understood by those knowledgeable of the prior art. The distal movement of the plunger or stopper  15  within the medicament cartridge  12  causes medication to be forced into the needle  11  of the hub  20 . The medicament cartridge  12  is sealed by septum  16 , which is punctured by a septum penetrating needle cannula  18  located within the hub  20 . The hub  20  is preferably screwed onto the lower housing  17 , although other attachment means can be used such as attaching to the cartridge. To protect a user, or anyone who handles the pen injection device  100 , an outer shield  69 , which attaches to the hub  20 , covers the hub. An inner shield  59  covers the patient needle  11  within the outer shield  69 . The inner shield  59  can be secured to the hub  20  to cover the patient needle  11  by any suitable means, such as an interference fit or a snap fit. The outer shield  69  and inner shield  59  are removed prior to use. The cap  21  fits snugly against outer sleeve  13  to allow a user to securely carry the drug delivery pen  100 . 
     The medicament cartridge  12  is typically a glass tube sealed at one end with the septum  16  and sealed at the other end with the stopper  15 . The septum  16  is pierceable by a septum penetrating cannula  18 , but does not move with respect to the medicament cartridge  12 . The stopper  15  is axially displaceable within the medicament cartridge  12  while maintaining a fluid tight seal. 
     The outer shield  69  and the inner shield  59  are removed from the hub  20  and needle  11  prior to injecting a patient with the medicament stored in the cartridge  12 . Some patients become uncomfortable at the sight of the needle  11 , which is visible prior to the injection. Accordingly, a need exists for a pen injection device having a hub assembly that prevents a patient from seeing the needle prior to an injection. 
     SUMMARY OF THE INVENTION 
     In accordance with an aspect of the present invention, a hub assembly for a pen injection device has a compressible member to prevent a patient from seeing the needle prior to an injection. 
     In accordance with another aspect of the present invention, the compressible member allows the needle to be primed without being seen by the patient. 
     The hub assembly for a pen injection device according to an exemplary embodiment of the present invention prevents a user from seeing the needle prior to the injection. A hub is connected to the pen injection device. A needle is received by the hub. A compressible member is connected to the hub and is movable between a first position that entirely covers the needle and a second position that exposes the needle for an injection. 
     Objects, advantages, and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above benefits and other advantages of the various embodiments of the present invention will be more apparent from the following detailed description of exemplary embodiments of the present invention and from the accompanying figures, in which: 
         FIG. 1  is a perspective view of an assembled existing pen needle assembly; 
         FIG. 2  is an exploded perspective view of the components of the pen needle assembly of  FIG. 1 ; 
         FIG. 3  is a perspective view of a hub assembly according to an exemplary embodiment of the present invention having a compressible member in a position covering a needle; 
         FIG. 4  is a perspective view of the hub assembly of  FIG. 3  in which the compressible member is compressed to expose the needle; 
         FIG. 5  is a side elevational view of a hub assembly according to another exemplary embodiment of the present invention having a compressible member in a position covering a needle; and 
         FIG. 6  is a side elevational view of the hub assembly of  FIG. 5  in which the compressible member is compressed to expose the needle. 
     
    
    
     Throughout the drawings, like reference numbers will be understood to refer to like parts, components and structures. 
     DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
     In an exemplary embodiment of the present invention, as shown in  FIGS. 3 and 4 , a hub assembly  101  for a pen injection device  100  ( FIG. 2 ) prevents a patient from seeing a needle  103  of the hub assembly during the injection. A hub  111  of the hub assembly  101  is connected to the pen injection device. The needle  103  is received by the hub  111 . A compressible member  121  is connected to the hub  111  such that the needle  103  is not visible during the injection. 
     The hub  111  is a typical hub, such as is shown in  FIG. 2 . The hub  111  has a body  113 , which preferably has a cylindrical shape, having a first end  112  and a second end  114 . A substantially planar base  115  is formed at the second end  114  of the hub body  113 . 
     The compressible member  121  is disposed on the hub  111 . An adhesive secures the first end  123  of the compressible member to the base  115  of the hub  111 . The compressible member  121  has a preferably substantially cylindrical shape. An opening  127  at a second end  125  of the compressible member  121  allows the needle  103  to pass therethrough during an injection. Preferably, the compressible member  121  is a sponge made of a soft foam material. 
     The compressible member  121  is compressible between a first position, as shown in  FIG. 3 , in which the compressible member  121  is not compressed and covers substantially the entirety of the needle  103  and a second position, as shown in  FIG. 4 , in which the compressible member is compressed to expose the patient end  104  of the needle. Applying downward pressure on the pen injection device  100  ( FIGS. 1 and 2 ) during an injection causes the compressible member  121  to compress, as shown in  FIG. 4 . Accordingly, the patient end  104  of the needle  103  is exposed such that medicament can be administered to the patient. After the medicament has been administered, the needle is removed such that pressure is no longer being applied to the compressible member. Accordingly, the compressible member  121  returns to the non-compressed position, as shown in  FIG. 3 . 
     The compressible member  121  may include a chemical indicator that changes the color of the compressible member when the needle  103  is primed. The medicament interacts with the chemical indicator, thereby causing a color change in the compressible member  121  to indicate priming of the needle. Accordingly, the needle  103  can be primed without the needle being seen by the patient. 
     The compressible member  121  may include adhesive microspheres. When the compressible member  121  is compressed, as shown in  FIG. 4 , the adhesive microspheres rupture. When the compressible member  121  moves back to the initial position, as shown in  FIG. 3 , the adhesive microspheres cure, thereby hardening the compressible member so that it is no longer compressible. 
     Another exemplary embodiment of a hub assembly  201  of the present invention is shown in  FIGS. 5 and 6 . The compressible member  221  is disposed on the hub  211 . Preferably, a friction fit between the hub post and the compressible  221  member secures the compressible member to the hub  211 . Alternatively, an adhesive may be used to secure a first end  223  of the compressible member  221  to the base  215  of the hub  211 . The compressible member  221  has a compressible bellows portion  225  and a non-compressible portion  227 . An opening  228  at a second end  229  of the compressible member  221  allows the needle  203  to pass therethrough during an injection. 
     The compressible member  221  is movable between a first position, as shown in  FIG. 5 , in which the compressible member  221  is not compressed and covers substantially the entirety of the needle  203  and a second position, as shown in  FIG. 6 , in which the compressible member is compressed to expose the patient end  204  of the needle. Applying downward pressure on the pen injection device  100  ( FIGS. 1 and 2 ) during an injection causes the bellows portion  225  of the compressible member  221  to compress, as shown in  FIG. 5 . Accordingly, the patient end  204  of the needle  203  is exposed such that medicament can be administered to the patient. After the medicament has been administered, the needle is removed such that pressure is no longer being applied to the compressible member  221 . Accordingly, the bellows portion  225  of the compressible member  221  returns to the non-compressed position, as shown in  FIG. 5 . 
     The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the scope of the present invention. The description of exemplary embodiments of the present invention is intended to be illustrative, and not to limit the scope of the present invention. Various modifications, alternatives and variations will be apparent to those of ordinary skill in the art, and are intended to fall within the scope of the invention as defined in the appended claims and their equivalents.