Abstract:
The present disclosure describes a needle guard device or system that can be used with drugs requiring reconstitution. The needle guard is preferably a passive needle guard that can be used during reconstitution without activating the safety mechanism. Following administration of the medication, the needle guard shields a user from inadvertent needle sticks by extending a protective shield over the needle.

Description:
CROSS-RELATIONSHIP TO PENDING APPLICATION 
       [0001]    This application claims priority to provisional application Ser. No. 60/941,209 filed May 31, 2007, and is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    This invention relates generally to syringe systems and methods for mixing and delivering a therapeutic agent formed by combining a diluent with a lyophilized drug or a concentrated drug. More specifically, this invention relates to syringe systems, including a passive needle guard, used for reconstitution of lyophilized or concentrated drugs and methods for using such systems. 
       BACKGROUND 
       [0003]    Lyophilization is a process by which the volatile components of a drug are removed in order to extend the shelf-life of the medication. Lyophilization may involve the rapid freezing of a material at a very low temperature followed by rapid dehydration. Solvents such as water are removed from the drug yielding a substance that is more stable and can be stored. Lyophilized drugs are generally stored in a glass vial or cartridge and covered by a rubber stopper or septum. 
         [0004]    In order to administer the lyophilized drugs, the drug must generally be reconstituted. Reconstitution is the process of hydrating drugs that are packaged and stored in a dry lyophilized state. A diluent, such as water, saline, 5% Aqueous Dextrose or the like, is added to the lyophilized drug and the combination is mixed until the drug is fully dissolved. A syringe is typically used to inject the diluent into the vial containing the lyophilized drug. The syringe may be pre-filled with the diluent or the user may first withdraw the diluent from a second vial or container into the syringe. After the diluent is added to the vial containing the lyophilized drugs, the contents are then mixed to form a therapeutic agent. 
         [0005]    After complete mixing of the diluent and the lyophilized drug, the therapeutic agent may be aspirated back into the syringe. Once the therapeutic agent is in the syringe, the medication is administered to the patient. Usually the therapeutic agent is administered within a short time after reconstitution in order to ensure that the drug is not degraded by the solvent. 
         [0006]    Most current systems for reconstitution expose the user to the risk of inadvertent needle sticks. In addition, current systems may not adequately prevent the possible reuse of the syringe. A number of needle guards for syringes have been developed that are intended to prevent accidental needle sticks and/or inadvertent reuse of a syringe. However, because syringe safety shield devices normally actuate when the plunger is fully advanced during the administration of the drug, these same devices will prematurely actuate the safety shield during the drug reconstitution phase as the diluent is added to the lyophilized drug. Therefore, a method for preventing the activation of the safety shield during drug reconstitution is highly desirable. 
         [0007]    Accordingly, a syringe system that can be used for reconstitution and that would automatically activate a needle shield during or following administration of the therapeutic agent would be considered useful. 
       SUMMARY 
       [0008]    The present invention is directed to a syringe system for reconstitution of lyophilized or concentrated drugs. The present invention is also directed to the combination of such a system with a passive needle guard that is automatically activated to extend a shield to cover a needle of the syringe and to methods of making and using such systems. Typically, a passive needle guard shield is activated when a radial portion or thumb pad of a plunger contacts a lateral catch or trigger finger of the passive needle guard. As the thumb pad of the plunger is moved distally, the trigger finger is forced laterally which results in a shield being forced distally to cover a needle of the syringe or in some designs, the syringe needle withdraws into the shield. 
         [0009]    The present disclosure describes a needle guard device or system that can be used with drugs requiring reconstitution without activating the safety mechanism, yet provides needle safety shielding after the drug has been injected into the patient. In a preferred embodiment, the needle guard device would be assembled and sold with a syringe that is preferably pre-filled with the diluent. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  shows an unassembled version of an exemplary embodiment of the device depicting the drug vial, drug vial adaptor, back plate, plunger, and the needle guard with an installed syringe. 
           [0011]      FIG. 2  shows an exemplary embodiment wherein the drug vial adaptor is removably coupled with the needle guard and syringe via luer fittings. 
           [0012]      FIG. 3  shows an exemplary embodiment of the device wherein a drug vial is removably coupled with the drug vial adaptor. 
           [0013]      FIG. 4  shows an exemplary embodiment of the device with the plunger pushed distally to expel the diluent in the syringe into the vial for the purpose of reconstituting the drug in the vial. 
           [0014]      FIG. 5  shows exemplary embodiment of the device with the plunger pulled back proximally after the drug has been reconstituted in the step depicted in  FIG. 4 . 
           [0015]      FIG. 6  shows an exemplary embodiment of the device after the reconstituted drug has been pulled into the syringe as shown in  FIG. 5  and the drug vial adaptor has been replaced with an injection needle. 
           [0016]      FIG. 7  shows an exemplary embodiment of the device showing the latched position of the shield trigger fingers. The curved under surface of the thumb pad of the plunger is in approximate contact with the proximal end of the trigger fingers. 
           [0017]      FIG. 8  shows a cut away view of the diagram in  FIG. 7 . The shield trigger fingers are shown engaging the body in the latched position. The latched position is achieved by contact between the latch surfaces of the shield trigger fingers and the body. 
           [0018]      FIG. 9  shows a profile sectional view of the diagram in  FIG. 8 . The dotted outline of the shield trigger fingers are shown in the unlatched position. The unlatched position is created when the plunger advances distally to an extent that the curved undersurface of the thumb pad pushes against the trigger fingers and displaces them laterally such that the latch surfaces of the shield trigger fingers and body are no longer engaged and will allow the shield to move distally with respect to the body. 
           [0019]      FIG. 10  shows an exemplary embodiment of the device with the shield in the extended position. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Turning to the figures,  FIG. 1  depicts an exemplary embodiment of the present needle safety guard device  5  and related components in an unassembled arrangement. As will be discussed in greater detail herein,  FIG. 1  shows a drug vial  200 , vial adaptor  150 , needle guard  40  housing a syringe  10 , back plate  90 , stopper  20 , and plunger  30 . In  FIG. 1 , the plunger  30 , stopper  20 , and supporting back plate  90  are shown separated from the rest of the safety device to better illustrate the components, however, in a preferred embodiment they are connected to the main part of the safety device  5  as shown in  FIG. 2 . 
         [0021]    In accordance with one aspect of the present disclosure, a medicine cartridge, such as a syringe  10  is provided ( FIG. 1 ). Preferably, the syringe  10  has a substantially smooth-walled cylindrical barrel  12 , a hub or distal end  14  that is the administration end, and a proximal end  16  having a flange  18 . The cylindrical barrel  12  typically is manufactured from substantially clear glass. Alternatively, the barrel  12  may be manufactured from plastic, e.g., polypropylene, k-resin, or polycarbonate, and the like. 
         [0022]    The barrel  12  of the syringe  10  may be pre-filled with a diluent, or may be filled with the diluent at a later step. Preferably the syringe  10 , if pre-filled, also comprises a label or markings that indicates the quantity and type of diluent. For example, a sticker or label may be attached to the barrel  12  of the syringe  10  which provides the name of the diluent and the volume of the diluent. The diluent may be of any type known in the art including, but not limited to, sterile water, saline, 5% Aqueous Dextrose or the like. Alternatively, the user may aspirate the diluent into the syringe from a vial or container. 
         [0023]    The proximal end  16  of the barrel  12  is configured to receive a stopper  20  and a plunger  30  ( FIGS. 1 and 2 ). The stopper  20  is configured to be slidably coupled into the cylindrical barrel  12  and movable from a proximal position to a distal position ( FIG. 1 ). The stopper  20  is preferably made of pliable rubber, thermoplastic rubber, plastic or similar material. The plunger  30  comprises a stem  32 , a distal end  34 , and a radial portion or thumb pad  36 . The plunger  30  is generally made of plastic, e.g. polypropylene, k-resin, or polycarbonate, or the like. 
         [0024]    The distal end  14  of the cylindrical barrel  12  comprises a needle port or luer fitting  17  ( FIG. 1 ). The luer fitting  17  may be configured to couple with several different sizes of needles with different diameters and lengths or with other components that include a luer fitting or other type of holder. The needles and components may be connected by a Luer connector, Luer slip, Luer, or other holder as is known in the art. The luer fitting can be either of the slip version (no threads) or include threads. The luer fitting  17  is configured to allow interchanging of the needle and/or components so a user may use the most appropriate needle or component during filling the syringe, reconstitution, and administration of the medication to a patient. 
         [0025]    The syringe  10  is housed inside the needle guard  40  wherein the needle guard  40  is preferably a passive needle guard ( FIG. 1 ). Safety shield devices generally function, by covering the needle with a rigid cylindrical shield that surrounds the needle and projects far enough beyond the distal tip of the needle so as to prevent a user&#39;s finger from coming in contact with the needle tip. To prevent a user from forgetting to deploy the safety shield, preferred safety devices operate passively or automatically by providing a mechanism that initiates and physically executes the shielding of the needle after the injection has been completed. The passive needle guard  40  generally comprises a body  50  for receiving and holding the syringe  10 , a shield  60  slidably attached to the body  50 , and a spring mechanism  55  ( FIG. 10 ). Both the body  50  and the shield  60  are generally molded from plastic, such as, polypropylene, k-resin, or polycarbonate, or the like. In a preferred embodiment, the body  50  and the shield  60  are substantially clear to facilitate observation of the syringe  10  therein. Alternatively, the body  50  and the shield  60  may be translucent or opaque, and may be colored, such as a latex color, a flesh tone, or a primary color. 
         [0026]    The body  50  may comprise opposing side rails defining two elongate openings or windows  51  extending at least partially between a proximal end  52  and a distal end  53  of the body  50  ( FIGS. 1 ,  9 , and  10 ). A substantially rigid collar is molded on the distal end  53  of the body  50 . The collar preferably has a substantially annular shape. The collar defines an opening  56  for allowing a needle  15  on a syringe  10  received in the opening  56  to extend distally beyond the body  50  ( FIGS. 1 and 6 ). 
         [0027]    The shield  60  is a tubular member adapted to slidably fit on the body  50  and has a proximal end  62  and a distal end  64 . In a preferred embodiment, one or more trigger fingers  66  extend proximally from the proximal end  62  of the shield  60  ( FIGS. 7-9 ). The trigger fingers  66  may include a first catch  68  that is configured to engage a second catch  58  on the proximal end  52  of the body  50  of the needle guard  40  ( FIGS. 8 and 9 ). Engagement between the first catch  68  and the second catch  58  retains the shield  60  in a first, retracted position. This latched configuration is further secured by an angled orientation of the latch surfaces, which when combined with the force of the spring  55  urging these surfaces against each other, places a component of force on the trigger fingers  66  directed toward the centerline. Preferably, the one or more trigger fingers  66  are elongate fingers having a proximal tip  67  that is engageable by the thumb pad  36  of the plunger  30  as it is depressed to axially compress and deflect the one or more trigger fingers  66  radially outwardly, as is discussed further below. 
         [0028]    The passive needle guard  40  also preferably includes a spring mechanism  55  coupled to the body  50  and the shield  60  for biasing the shield  60  towards an extended position when the trigger fingers  66  are deflected radially ( FIG. 10 ). 
         [0029]    The back plate  90  is removably coupled with the needle guard  40 . The back plate  90  creates a physical barrier to removal of the plunger from the needle guard safety device  5 . The back plate  90  includes an aperture  92  dimensioned to receive the stem  32  of the plunger  30 , wherein the aperture is of a smaller size than a distal end of the plunger. When the plunger is moved proximally, the back plate  90  prevents a user from accidentally removing the plunger  30 . 
         [0030]    The syringe  10  can be used to administer a lyophilized or concentrated drug to a patient. The lyophilized drug or concentrated drug may be of any type known to those of skill in the art. Preferably, the lyophilized or concentrated drug is stored in a vial  200  or container such as a glass vial ( FIG. 1 ). The vial  200  may include a cover  210  such as a rubber stopper, septum, or cap that can be penetrated by a needle. In a preferred embodiment, the vial  200  is made of a substantially clear glass so that the user can ensure that the diluent and lyophilized drug have been properly and fully mixed. 
         [0031]    The drug vial adaptor  150  connects onto the end of the vial  200  that has the septum (FIGS.  1  and  3 - 5 ). The vial adaptor  150  has a thin pointed distal end  152  and a luer fitting  154  on the proximal end  156 . An inner channel runs from the sharp distal end  152  to the proximal luer fitting  154  ( FIG. 2 ). The vial adaptor luer fitting  154  is attached to the luer fitting  17  on the syringe  10  and the vial adaptor  150  is then attached to the vial  200  ( FIGS. 2 and 3 ). The sharp distal end  152  of the vial adaptor  150  is sized to penetrate the vial septum as it connects to the vial  200 , thus creating a fluid channel between the syringe  10  and vial  200 . 
         [0032]    The steps of reconstituting the drug and administering it into the patient would be to install the drug vial adaptor  150  onto the syringe  10  inside the needle guard  40  via their respective luer fittings  17 ,  154  ( FIG. 2 ). The drug vial  200  is then attached to the drug vial adaptor  150  creating a fluid-communicating channel between the vial  200  and the syringe  10  ( FIG. 3 ). The plunger  30  is then advanced to expel the diluent from the syringe  10  into the drug vial  200  ( FIG. 4 ). 
         [0033]    It is at this point that the problems with existing safety devices would arise, since advancing the plunger  30  to expel the diluent in the drug vial  200  would trigger the safety shield mechanism of exiting safety devices. With the shield now covering the distal end of the device, the rest of the reconstitution steps would be impossible to perform and, additionally, the injection needle would not be accessible in order to inject the patient. 
         [0034]    To prevent the relative motion of the safety shield  60  during the steps of reconstitution, it has been discovered that a component (e.g., a vial adaptor  150 ) attached to the luer connection  17  of the syringe  10  will prevent the relative motion of the safety shield  60  if it is of a sufficient diameter and proximity to the safety shield  60 . As the vial adaptor  150  is installed and tightened onto the syringe luer fitting  17 , it will be advanced proximally relative to the safety shield  60 , and when appropriately sized, will come in proximity to the safety shield  60  in a manner preventing any distal motion of the safety shield  60  relative to the syringe  10  or the rest of the safety device  5 . 
         [0035]    The plunger  30  can then travel the full stroke to empty the syringe contents during reconstitution. Even though the safety shield mechanism will have been triggered (i.e. the thumb pad  36  will contact the trigger fingers  66 ), the shield  60  will not advance to the shielded position because the interaction of the vial adaptor  150  (or other component), shield  60 , and luer fitting  17  prevents it from doing so. Because the trigger fingers  66  have an elastic force urging them back into the latched position, the latch mechanism is reversible if the shield  60  has not moved forward. When the plunger  30  is pulled proximally to draw the drug mixture from the vial  200  into the syringe  10 , the trigger fingers  66  will relatch themselves against the second catch  58  on the body  50  so that the needle guard  40  is able to trigger the next time the plunger  30  is advanced sufficiently distally. 
         [0036]    After the drug has been dissolved in the diluent, the plunger  30  is withdrawn proximally, pulling the drug mixture into the syringe  10  ( FIG. 5 ). In a preferred embodiment, a circumferential rib  35  on the distal end  34  of the plunger  30  interferes with the plunger support back plate  90  preventing the full withdrawal of the plunger  30 , so that users will not inadvertently and surprisingly remove the stopper  20  from the syringe  10  and expose the drug to a non-sterile environment ( FIG. 1 ). The vial adaptor  150  (with the vial  200 ) is removed from the syringe luer fitting  17  and replaced with an injection needle  15  having a luer fitting ( FIG. 6 ). The medication is now ready for injection into the patient and the needle guard  40  should deploy in the normal manner after the medication has been injected into the patient. 
         [0037]    As discussed above, the thumb pad  36  of the plunger  30  is sized and shaped to displace the trigger fingers  66  laterally away from the latched position that connects them to the body  50  to an unlatched position that substantially disconnects them from the body  50  when the plunger is advanced sufficiently far forward distally, preferably far enough forward that the contents of the syringe  10  has been expelled, but before the plunger  30  is arrested by the stopper  20  reaching the distal end of the syringe  10  ( FIG. 9 ). As the medication is being injected into the patient with the vial adaptor  150  removed, the plunger  30  will displace the trigger fingers  66  causing the force of the spring  55  to move the shield  60  forward preventing the trigger fingers  66  from relatching and initiating the deployment of the safety shield  60 . The dotted lines in  FIG. 9  depict the movement of the trigger fingers  66  from the latched position to the unlatched position. 
         [0038]    After the plunger  30  is fully advanced and the safety shield mechanism has been released, the shield  60  is either moved distally relative to the syringe  10  and needle  15  or the syringe  10  and needle  15  are moved proximally with respect to the shield  60 . Passive or automatic deployment of the safety shield  60  is accomplished by way of the compression spring  55  pushing the shield  60  distally and/or the syringe  10  and needle  15  proximally. The spring force is released to the shield  60  and body  50  when the trigger fingers  66  are displaced from the latch configuration. The spring  55  is of sufficient size to move the shield  60  far enough to sufficiently shield the needle  15  from the user ( FIG. 10 ). In a preferred embodiment, a locking mechanism holds the shield in the extended position. The locking mechanism may comprise, for example, a set of cooperating detents or catches on the shield  60  and body  50  that maintain the shield in the extended position. Regardless of the relative motion of the safety shield  60 , what is common to all devices is that the safety shield  60  is actuated after the plunger has been advanced to empty the syringe contents. 
         [0039]    Examples of devices that could be used to attach to the syringe luer fitting and to prevent the forward advance of the shield are not limited to drug vial luer adaptors  150 . Others could include female-to-female and female-to-male luer adaptors, luer adaptor fittings on disposable sets, filters with luer fittings, etc. provided that they have the correct geometry to prevent the shield from deploying. In addition, luer connections are widely used in the medical device industry, but any similar releasable connection could also function to hold the drug vial or similar device in proximity to the shield to prevent it from being deployed. 
         [0040]    Although preventing the shield from deploying or moving distally over the syringe has been described, it is understood that the present invention would also apply to devices that move the syringe and needle proximally. Furthermore, the trigger finger based latch mechanism has been described in detail, but it is understood that any mechanism that triggers the deployment of a safety shield could be used. 
         [0041]    While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims.