Abstract:
A device that prevents the accidental activation and lockout of an autoinjector. In illustrative embodiments, a resistance unit is configured to resist deployment of the needle until a critical force is applied by the user to the autoinjector, at which point, the resistance of the resistance unit is overcome. Continuous application of force by the user after the resistance is overcome drives the delivery device to the injection site where the medication is administered.

Description:
BACKGROUND 
     Field 
       [0001]    The present disclosure relates to devices and methods of administering, injecting, and/or delivering substances to a patient. More particularly, and without limitation, the disclosed embodiments relate to preventing inadvertent lockout of an autoinjector typically employed in regimented therapies and emergency situations. 
       Description of Related Prior Art 
       [0002]    Autoinjector delivery systems are devices that facilitate hypodermic administration or self-administration of a predetermined dosage of medication. Often times, a patient&#39;s therapeutic regimen calls for periodic, for example, daily or weekly administrations of medication using autoinjectors. For example, in the treatment of multiple sclerosis, some patients are prescribed daily injections of disease modifying drugs, such as Interferon beta 1a for the treatment of multiple sclerosis, or, for example, AVONEX® available from Biogen. Auto injectors are also useful in emergency situations. Anaphylaxis, for example, is a serious allergic reaction that occurs rapidly and may cause death. Typically caused by contact with animals, food, and/or medication, common symptoms of anaphylactic shock include an itchy rash, throat swelling, and low blood pressure. In such cases, the immediate administration of epinephrine, antihistamines, and/or steroids is desirable. 
         [0003]    Typically, autoinjectors have a syringe or similar structure containing drug substances. The syringe is disposed within a housing and is displaced by a spring when activated, causing a needle to be exposed to an injection site. After the injection occurs and the medication has been expelled from the syringe, a needle guard is deployed to prevent any harm, such as puncture injury and/or contamination, that may otherwise result from an exposed needle. Further, post injection, the needle can assume a lockout condition, wherein the needle is locked into its retracted position and cannot be deployed a second time. The lockout condition can also provide a user with one or more indicators—e.g., visual, tactile, etc.—that indicate whether the single-use autoinjector has already been used, prevents its reuse, and avoids harm that might result from an exposed needle. 
         [0004]    An inadvertent lockout problem can arise during use of the autoinjector from hesitation or misapplication. Inadvertent lockout renders the autoinjector useless for its intended purpose as if the medication has been expelled from the single use device. This inadvertent lockout can occur in patients who regularly use autoinjectors, and is not limited to the less practiced environment where the autoinjector is used in emergency situations. The consequences of an inadvertent lockout in an emergency situation can be more dire, however, for example where anaphylaxis is present and time is of the essence. 
         [0005]    During an emergency, the stress of the moment can cause anxiety and nervousness in the user, which can affect the user&#39;s technique. Likewise, the ability of the person receiving an injection to remain still can be affected. Hesitation and apprehensive fidgeting with the autoinjector is therefore a common result, which often prolongs the time required for successful administration. Additionally, a user&#39;s unfamiliarity with an autoinjector can create uncertainty regarding how to activate it, and where on the body to deliver the injection. These factors can increase the chance of injection failure because, as explained above, the autoinjector&#39;s lockout mechanism is designed so that the user has only one chance to administer the medication properly. 
         [0006]    Under the most unfortunate circumstances, users have been known to accidentally activate the autoinjector prematurely, causing the medication to wastefully dispense and the lockout condition to occur before the autoinjector is securely placed at the injection sight. In other instances, the lockout can be inadvertently activated without dispensing the medication, rendering the medication inaccessible. Inadvertent lockout of the autoinjector under either circumstance renders the medication unavailable for therapeutic use, which renders the autoinjector useless for its intended purpose. 
       SUMMARY 
       [0007]    The disclosed embodiments include devices that prevent the inadvertent lockout of an autoinjector. 
         [0008]    In illustrative embodiments, a lockout prevention device is provided for an autoinjector having a housing, a delivery device, and a needle guard. The delivery device contains a syringe or vial filled with a medication for example; it may have a needle located at one end that is enclosed by the needle guard. The needle guard is connected to the delivery device and is configured to retract into the housing so that the needle dispenses medication at an injection site. The lockout prevention device may comprise a resistance unit configured to contact the delivery device in a first position, thereby obstructing the displacement of the needle guard and preventing the delivery device from moving through the housing. 
         [0009]    To move the resistance unit from the first position to a second, where the resistance unit no longer obstructs the delivery device from traveling to the injection site, a user must overcome a resistance by applying a critical force to the needle guard. After the resistance is overcome, the needle guard can retract freely into the housing such that application of a lesser, injection force to the needle guard exposes the needle to the injection site where the medication is administered. The lesser, injection force may be achieved from momentum generated by applying the critical force. Therefore, in an exemplary operation, a user must overcome a resistance by applying a critical force to the autoinjector in order to prepare it for injection, and, once overcoming the resistance, provide a lesser force sufficient to make the injection and lockout occur. Accordingly, another aspect of the disclosed embodiments is to assist users in making a proper injection by allowing the them to practice applying an activating force without lockout occurring. This training prevents hesitation, apprehensive fidgeting, and/or misapplication of the autoinjector that might otherwise cause an inadvertent lockout. 
         [0010]    According to exemplary embodiments of the current disclosure, a user is required to overcome a resistance at the injection site before the injection occurs in order to better prepare a patient for the impending injection. Overcoming the resistance trains the user to apply a force sufficient to activate the autoinjector without lockout occurring. Beneficial training also results from a user applying a force to the injector that does not exceed the critical force such that the resistance is not yet overcome. The user&#39;s mental preparedness is further enhanced because overcoming the resistance builds momentum that carries the user through the injection process with confidence. Therefore, yet another aspect of the disclosed embodiments is to increase the level of a patient&#39;s preparedness when using an autoinjector to allow for a proper, confident injection. 
         [0011]    Other embodiments of this disclosure are disclosed in the accompanying drawings, description, and claims. Thus, this summary is exemplary only, and is not to be considered restrictive. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0012]    The accompanying drawings, which are incorporated in and constitute part of this specification, and together with the description, illustrate and serve to explain the principles of various exemplary embodiments. 
           [0013]      FIG. 1  depicts an exemplary autoinjector device with a resistance unit in a first position according to the present disclosure. 
           [0014]      FIG. 2  depicts an exemplary view of the autoinjector of  FIG. 1  with the resistance unit in a second position according to the present disclosure. 
           [0015]      FIG. 3  depicts an exemplary resistance unit in a first position according to the present disclosure. 
           [0016]      FIG. 4  depicts an exemplary resistance unit of  FIG. 3  in a second position according to the present disclosure. 
           [0017]      FIG. 5  depicts an alternative exemplary resistance unit according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0018]    The claimed subject matter is described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the subject innovation. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing the subject innovation. Moreover, it is to be appreciated that the drawings may not be to scale. Moreover, the words “exemplary” or “illustrative” are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs. 
         [0019]    According to an illustrative embodiment of the disclosure, an autoinjector  10  has a lockout prevention mechanism. In an exemplary embodiment, the autoinjector  10  has a housing  12 , a delivery device  20 , a needle guard  30 , and a resistance unit  50 . Preferably, the housing  12  is made from thermoplastic, but any other suitable material can be used in accordance with the present disclosure. The delivery device  20  is preferably made from glass, but, again, any other suitable material can be used in accordance with the present disclosure. 
         [0020]    In an exemplary embodiment shown in  FIG. 1 , the housing  12  includes an elongated body  14  that is hollow. The elongated body  14  has two ends—a closed proximal end (not shown), and an open distal end  16 . The open distal end  16  of the housing  12  provides an opening  18  through which the delivery device  20  protrudes. The housing  12  is sufficiently large to allow for enhanced, ergonomic handling. To further enhance the easy of handling, the housing  12  can, for example, have a textured outer surface, ribs disposed thereon, and/or a curved housing. Also, in an exemplary embodiment, the housing  12  is comprised of two or more materials, wherein at least one material has improved gripping qualities over the other(s). 
         [0021]    In an exemplary embodiment, the housing  12  has a viewing window (not shown) in the elongated body  14  that allows a user to observe the delivery device  20  disposed therein. The viewing window can comprise an open aperture in a wall of the elongated body of the housing  12 , or the open aperture can be covered by a transparent or translucent member. By enabling observation of the viewing window, an additional indicator as to the status of the delivery device  20  is provided. This can be useful to determine whether the delivery device  20  contains contents, determine whether said contents have already been dispensed, and to observe dispensing while it occurs. 
         [0022]      FIG. 1  further discloses an exemplary embodiment of the delivery device  20  within the housing  12 . The delivery device  20  may comprise a syringe  21  or vial disposed within a holder  23 . In some embodiments, the syringe  21  contains a medication, and can also contain other materials, such as, for example, vitamins and/or other therapeutic substances. The holder  23  cooperates with the syringe  21  when the syringe  21  is exposed to an injection site. As discussed in further detail below,  FIG. 1  depicts a needle  22  of the syringe  21  disposed within the housing  12  while the resistance unit  50  is in a first position. Because the needle  22  is fully enclosed by the needle guard  30 , it avoids contact with contaminating objects or surfaces. 
         [0023]    Both the syringe  21  and the holder  23  of the delivery device  20  are connected to a needle guard  30 . A portion of the needle guard  30  extends beyond the open distal end  16  of the housing  12 . The needle guard  30  encloses the needle  22  attached to the syringe  21  so that a user never has to view the needle. This feature therefore provides a benefit to patients with a phobia of needles. As shown in  FIG. 1 , the needle guard  30  is can be cylindrically shaped and hollow, so as to surround the delivery device  20 , but it should be appreciated that other shapes, in addition to hollow cylinders, are contemplated (e.g., rectangular shaped hollow needle guards). The needle guard  30  is movable within and/or retractable into the housing  12 . The needle guard  30  further comprises a spring mechanism (not shown) that is triggered by moving the needle guard  30  towards the closed proximal end of the housing  12 . (The internal drive mechanism, including the spring mechanism, of the autoinjector may not be germane to the illustrative embodiments as herein disclosed. But the internal drive mechanisms disclosed in U.S. Pat. No. 7,442,185 and U.S. Patent Pub. No. 2014-0309591 are herein incorporated by reference.) Movement of the needle guard  30  beyond a critical point triggers the spring mechanism, which, as stored, contains potential energy. The spring mechanism is connected to a plunger of the syringe  21  so that, when triggered, it moves the plunger, located at least in part inside the delivery device, towards the needle  22  to facilitate dispensing. 
         [0024]    After injection and dispensing occur, a portion of the needle guard  30  extends back outside of the housing  12  via a negative spring disposed inside the housing  12  at the open distal end  16  thereof. Also, the needle guard  30  is locked into an extended position such that a portion of the needle guard  30  extends outside of the housing  12  beyond the open distal end  16  thereof. This configuration is known as the lockout condition. The lockout conditions prevents the needle  22  extending beyond the needle guard  30 . Further, it allows a user to appreciate that the autoinjector  10  has been used and is ready for disposal. 
         [0025]      FIG. 1  further depicts an exemplary embodiment of an assembly of the autoinjector  10  with the resistance unit  50  disposed within a distal end of the needle guard  30  in the first position. The resistance unit  50  comprises a ring  51  and a base  55 . The ring  51  is connected to, and movable within, the base  55 . In some embodiments, the ring  51  comprises at least two protrusions  52  extending from a perimeter thereof. The protrusions  52  are diametrically opposed to one another. The protrusions  52  are received by arms  59  of the base  55  to secure the resistance unit  50  in the first position. As shown in  FIG. 1 , when in the first position, the ring  51  abuts an end of the holder  23  of the delivery device  20 , thereby preventing: (1) the spring mechanism from triggering; and (2) the delivery device  20  from being exposed to an outside of the housing  12  and to the injection site. 
         [0026]    As shown in  FIG. 3 , the base  55  is comprised of an annular end  56  and a skirt  57  proximally extending away from the annular end  56 . In one embodiment, the skirt  57  has a skirt opening  58  for receiving the protrusions  52  of the ring  51 . The skirt  57  further has arms  59  proximally extending away from the skirt  57  so as to assume a cantilevered configuration. Distal ends of each arm contain a recess  54  for securely positioning the protrusions  52  of the ring  51  therein. In this way, the ring  51  is secured to the base  55  at a distance away from the annular end  56  when in the first position. Further, as discussed below, because the arms  59  are cantilevered from the skirt  57 , applying a critical force to the needle guard  30  will cause the arms  59  to flex outwardly. As a result, the ring  51  will be released from the recess  54  and fall to the annular end  56  of the base  55 , as shown in in  FIG. 4 . The autoinjector  10  is ready for administration only after the critical force is applied to the needle guard  30  to free the ring  51  from the arms  59  of the resistance unit  50 . After, a user can apply a lesser injection force to administer the medication contained in the autoinjector  10 . 
         [0027]    Alternative embodiments of the resistance unit  50  have been contemplated in accordance with the present disclosure. For example, in some embodiments, the resistance unit  50  is formed integrally with the needle guard  30 . In another embodiment, the base  55 , for example, need not have arms  59  cantilevered from a skirt  57  in order to provide a means for maintaining the ring  51  in the first position. The entire skirt  57 , for example, can extend further away from the annular end  56  and provide a recess  54  for receiving the protrusions  52  of the ring  51 . So long as the resistance unit  50  obstructs the needle guard  30  from retracting into the housing  12 , the resistance unit  50  can assume any configuration. 
         [0028]    For example, in another embodiment, the ring  51  shown in  FIG. 1  that abuts a distal end of the holder  23  need not be a ring at all; rather, it could assume different shapes, such as, for example, an arcuate shape or a straight bar with a hole in its center to accommodate the needle  21 . 
         [0029]    In another embodiment, there is no ring  51 ; instead, at least one arm extends away from the annular end  56  of the base  55  and abuts the distal end of the holder  23  to prevent movement of the needle guard  30  towards the closed proximal end of the housing. Distal ends of the at least one arm may have a chamfered surface or detent extending therefrom that cooperates with the distal end of the holder  23 , such that when a force applied to the needle guard  30  exceeds a critical point, the arm flexes and is freed from the holder  23 , allowing the injection process to proceed. 
         [0030]    In other embodiments, the resistance unit  50  comprises at least one arm that has a frangible portion that is disposed within the needle guard  30  and abuts the distal end of the holder  23 . During use, the frangible portion can collapse in response to a critical force being applied to the needle guard  30 , thereby allowing the needle guard to move towards the closed proximal end of the housing  12  to trigger the spring mechanism. 
         [0031]    In another embodiment, an autoinjector  110  has a resistance unit  150  that is integral with a needle guard  130 . The resistance unit  150  can comprise at least one cantilevered spring  152  that is attached to the body of the needle guard  130  on one end, and has a protrusion  153  extending from another, distal end thereof. The protrusion has a ramped surface  154  that abuts an open distal end  116  of the housing  112 . In use, as a user presses down on the autoinjector  110  at the injection site, the needle guard  150  is moved towards the closed proximal end of the autoinjector. As the force applied to the needle guard  130  increases, the open distal end  116  of the housing  112  travels along the ramped surface  154  of the cantilevered spring  152 , moving the cantilevered spring towards an interior of the needle guard  130 . When the force applied exceeds a critical force, the needle guard  130  can move freely through the housing  112  to trigger the spring mechanism (not shown), causing the injection to occur. 
         [0032]    According to the exemplary embodiment of the present disclosure, the autoinjector  10  can also include a removable end cap (not shown) that encloses the open distal end  16  of the housing  12 , including the delivery device  20 , needle guard  30 , and resistance unit  50 . The closure protects critical features of the autoinjector  10  against harm during transport and storage. The end cap is selectively removable when the autoinjector  10  is ready for use. Also, the end cap can be re-applied to the autoinjector  10  thereafter to further prevent contact with the needle  22 . In some embodiments, the end cap has a ribbed or textured outer surface, which may comprise a different material than other portions of the autoinjector, for enhanced gripping and handling. 
         [0033]    In operation, the removable end cap is removed from autoinjector  10  to reveal the needle guard  30  and the resistance unit  50  in the first position, as depicted by the exemplary embodiment in  FIG. 1 . A user will then position the autoinjector  10  at the injection site. While in the first position, the ring  51  of the resistance unit  50  abuts or is immediately adjacent to a distal end of the holder  23 . The user will then apply a critical force by pressing the autoinjector  10  against the injection site. Application of the force to the needle guard  30  urges it towards the closed proximal end of the housing  12 . A slight displacement of the needle guard  30  towards the closed proximal end of the housing  12  causes the ring  51  to contact an end of the holder  23 , and opposing forces to be applied to the ring  51  and arms  59  of the resistance unit  50 . As the force applied exceeds a predetermined criticality and the arms  59  flex outwardly, the ring  51  is released from them, allowing the resistance unit  50  to move into a second position wherein the ring  51  rests against the annular end  56  of the base  55 . At which point, the autoinjector  10  is ready for injection. 
         [0034]    However, prior to exceeding the critical force required to free the ring  51  from the arms  59 , a user could, optionally, repeatedly approach the criticality by asserting a lesser force to the needle guard  50  without risking inadvertent lockout because the arms  59  are designed to provide enough resistance to allow a user to practice before injecting the needle  21 . In some embodiments, the critical force required to overcome the resistance caused by the resistance unit  50  can be substantially between five and ten pounds. 
         [0035]    After exceeding the critical force, the confidence of the user is advantageously buoyed because he or she is better prepared mentally for the impending injection. A user can then apply a lesser, injection force to the needle guard  30  (which generally results from momentum caused by application of the critical force) continuously pressing the needle guard  30  against the injection site to move the needle guard  30  towards the closed proximal end of the housing  12 . Displacement of the needle guard  30  beyond a critical point triggers the spring mechanism, which exposes the syringe  22  and drives the plunger of the delivery device  20  to the injection site, thereby dispensing the medication. 
         [0036]    By this exemplary administration process, a user may avoid hesitating or fidgeting with the autoinjector  10 , thereby preventing an inadvertent lockout and the associated consequences discussed above. Further, the user&#39;s preparedness is enhanced because overcoming the resistance of the resistance unit  50  builds momentum that carries the user through the injection process with confidence. 
         [0037]    While the foregoing drawings and descriptions set forth functional aspects of the disclosed systems, no particular arrangement of these functional aspects should be inferred from these descriptions unless explicitly stated or otherwise clear from the context. Similarly, it will be appreciated that the various steps identified and described above may be varied, and that the order of steps may be adapted to particular applications of the techniques disclosed herein. All such variations and modifications are intended to fall within the scope of this disclosure. As such, the depiction and/or description of an order for various steps should not be understood to require a particular order of execution for those steps, unless required by a particular application, or explicitly stated or otherwise clear from the context. 
         [0038]    Further, while embodiments of the present disclosure have been disclosed in connection with the preferred embodiments shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present disclosure is not to be limited by the foregoing examples, but is to be understood in the broadest sense allowable by law.