Patent Publication Number: US-2022211950-A1

Title: Detachable needle protection cap for injection devices

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 16/353,805 filed on Mar. 14, 2019 which is a continuation of International Application No. PCT/CH2017/000081 filed on Sep. 6, 2017, which claims priority to Swiss Application No. 1224/16 filed Sep. 21, 2016, the entire contents of all of which are incorporated by reference herein in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to detachable needle protection caps for injection devices, in particular for injection pens and autoinjectors, in which pre-filled syringes are used as product containers and with which a liquid product contained therein can be dispensed. The liquid product in question is a medicinal product in particular. The invention essentially relates to detachable needle protection caps for injection devices, which can be cheaply adapted to the needs of various medical indications. 
     BACKGROUND 
     An injection device, such as an injection pen, an autopen or an autoinjector is, in principle, suitable for dispensing various medicaments, provided that the medicament is of a consistency that can be dispensed using the injection device. However, there are differences which are caused indirectly by the medical indications, for which the various medicaments are used. Thus, because of the indication, various demands may be made in terms of size, shape, surface and mechanical properties of the housing of the injection device. For example, in the case of diseases such as multiple sclerosis (MS), the mobility of the patient may be restricted, meaning that for an injection device which is used to treat patients with MS, particular demands are made on the shape of the device, so that the patients can handle the injection device in the first place. Thus, for medical indications which concern the handling of injection devices by children or small people, it may be necessary for injection devices to be designed as slim and small as possible. 
     For injection devices where a prefilled syringe is used as a product container, a so-called detachable needle protection cap is often used so as to be able to remove the needle protection from the syringe prior to injecting. Using the detachable needle protection cap, the person using the unit can remove the needle protection from the syringe by hand. It is immediately obvious that the shape and design of the detachable needle protection cap must likewise be adapted to the application (as described above). 
     The term “medicament” in this case includes any fluid medicinal formulation, which is suitable for controlled administration through a means, such as a cannula or hollow needle, for example, including a fluid, a solution, a gel, an emulsion or a fine suspension, which contains one or more active medicinal substances. A “medicament” may be a composition of a single active substance or a premixed or co-formulated composition of several active substances from one single container. Medicament includes drugs such as peptides (e.g. insulins, insulin-containing medicaments, GLP-1-containing as well as derivatives or similar preparations), proteins and hormones, biologically obtained or active substances, active substances based on hormones or genes, nutritional formulations, enzymes and other substances both in solid (suspended) or liquid form, as well as polysaccharides, vaccines, DNA or RNA or oligonucleotides, antibodies or parts of antibodies, as well as suitable base, auxiliary and carrier substances. 
     An injection device is known from WO 15110532 A1, which comprises a multi-part detachable needle protection cap. The detachable needle protection cap comprises a cap  50  and an insert  90 , which are connected by a single snap-on connection. A particular variant, which is designed in one piece, is provided for the cap  50 . 
     For manufacturers of injection devices, drug manufacturers, health insurers and patients, there is a need for injection devices to be readily available, which are as cheap as possible but which are safe and effective. Accordingly, it would be desirable to have a detachable needle protection cap for an injection device, which comprises a consistent, tried and tested, safe and prescribed technical design with a consistent housing, where connection is made by additional components, which are permanently and non-detachably connected to the housing of the injection device as well as connected to the detachable needle protection cap and where the shape, feel, surface topography and ergonomy of the injection device can still be adapted during production of the device, thereby taking account of the needs of the medical indication in a simple and cost-effective way. 
     The invention provides detachable needle protection caps for injection devices, which can be cost-effectively adapted to the needs of various medical indications. 
     SUMMARY OF THE INVENTION 
     Such needle protection caps are provided for instance by the device according to independent claim  1  and the process according to the independent claim  6 . Advantageous further developments can be seen from the dependent claims, the description and figures. 
     In the following description, the terms ‘distally’ and ‘proximally’ are used in relation to positions and directions. For example, the distal end of the injection device means the end of the injection device where the injection needle is attached. The distal direction then indicates the direction in which the tip of the injection needle points. In other words, ‘proximal’ then describes the end opposite the distal end, or the direction which is opposite the distal direction. 
     The function of the detachable needle protection cap is briefly explained below using an autoinjector in the shape of a pen as an example. However, other injection devices with a detachable needle protection cap according to the invention could also be used if a prefilled syringe is used as the product container in said injection devices. The injection devices may, in particular, also be injection pens or autopens. 
     Typically, prefilled syringes are used as medicament containers in autoinjectors. An injection needle is permanently attached at the distal end of the syringe. The injection needle is protected, prior to use, by a needle guard in the form of a rubber cap (possibly with a reinforced support frame), where the rubber cap also forms a sterile barrier. When assembling the autoinjector, the prefilled syringe is pushed into the autoinjector, where it is fixed. The distal end of the autoinjector is formed by the detachable needle protection cap, which makes it possible to remove the needle guard from the prefilled syringe before the autoinjector is used, without the person using the syringe running the risk of pricking himself on the injection needle. 
     In one aspect of the invention, the detachable needle protection cap comprises a housing. The housing together with the autoinjector defines a longitudinal axis and the radii are defined as perpendicular to the longitudinal axis. To detach the needle guard from the prefilled syringe, at least two flexible arms are located on the housing, which point in the proximal direction and the proximal ends of which have hook-like structures, which protrude radially inward behind the proximal end of the needle protection cap when the detachable needle protection cap is placed on the autoinjector. If the detachable needle protection cap is now removed from the autoinjector in the distal direction, then the hook-like structures grip the needle guard and detach it from the prefilled syringe. 
     In principle, the housing of the needle protection cap is approximately cylindrical in shape and the housing may include areas of different diameters. On the outer surface of the housing of the detachable needle protection cap, additional elements are arranged, which makes it possible to attach and fix additional parts. 
     In one aspect of the invention, the detachable needle protection cap also comprises at least two shell parts, which can be fitted on the outside of the housing. The shell parts comprise complementary elements, particularly attachment and guide elements which, when engaged with the elements on the outside of the housing, enable the shell parts to be fixed to the housing. Furthermore, the shell parts comprise blocking elements, which can prevent the shell parts from becoming detached after fitting to the housing. According to the invention, the blocking elements of a shell part block the complementary elements from becoming detached from another shell part and vice-versa, which has the advantage that when the at least two shell parts are fixed to the housing, non-destructive detachment of the shell parts is rendered impossible (without parts of the detachable needle protection cap being damaged). 
     The positioning of the complementary elements and the blocking elements on the shell parts can be seen from the arrangement of the elements on the external surface of the housing. 
     The at least two shell parts enable the external shape of the detachable needle protection cap to be adapted to specific needs, without having to make modifications to the housing and function of the detachable needle protection cap. No modifications have to be made to the injection device either, provided that the shape and size of the shell parts do not interfere with the injection device. Therefore, when designing the shell parts, particular care must be taken that the complementary elements are positioned geometrically correctly and that they fit the housing. In addition, there are numerous design possibilities of adjusting the ultimate external shape of the detachable needle protection cap to specific needs. 
     In their entirety, the shell parts can fully envelop the housing (provided it is outside the injection device when assembled)—in this way, the shell parts may, for example, be developed as half shells. As an alternative, the shell parts may also only cover certain areas of the housing. 
     As mentioned, the interaction between the elements, complementary elements and blocking elements is designed in such a way that once all the shell parts have been fitted to the housing, the shell parts can no longer be removed from the housing, so that the user is unaware of the multiple parts of the detachable needle protection cap. For this purpose it is important that the shell parts can be fitted permanently and immovably relative to the housing. 
     In one aspect of the invention, the complementary elements of the shell parts comprise snap arms, on the one hand, and the elements on the external surface of the housing comprise recesses, into which the snap arms can be locked. The complementary elements also comprise guide ribs and the elements comprise guide groves, which run roughly perpendicular to the longitudinal axis. The guide grooves comprise undercuts. So that a shell part can be snapped onto the housing, the shell in question is pushed radially onto the housing, so that the guide ribs can be moved into the provided grooves. The cross-section of the guide ribs is such that the ribs engage in the undercuts of the guide grooves. The shell part is slid on so far until the snap arms click into the recesses. 
     In one aspect of the invention the detachable needle protection cap comprises two shell parts, which are developed as half shells, so that once the first shell part has been pushed onto the housing, the second shell part is pushed onto the side of the housing opposite the first shell part and the guide ribs of the second shell part are likewise pushed into guide grooves. When the snap arms engage in the recesses, the blocking elements of the second shell part block the snap arms of the first shell part and vice-versa. This prevents the shell parts from becoming detached from the housing, as explained below. In one aspect of the invention, the result of the undercuts in the guide grooves of the housing is that the shells can only be moved minimally in the radial direction, in other words, within the limits of play in the guide groove/guide rib joint. Preferably, the guide grooves and guide ribs are combined in a dovetail. 
     In an alternative embodiment of the invention, the guide grooves may be arranged on the shell parts and the guide ribs on the external surfaces of the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 : three-dimensional or perspective view of the autoinjector  1  with the detachable needle protection cap  100 . 
         FIG. 2 : simplified exploded view of autoinjector  1  with detachable needle protection cap  100 , where only the housing  2  of the autoinjector and the needle protection sleeve  6  of the autoinjector are shown (for reasons of clarity, the other parts of the autoinjector are not shown). 
         FIG. 3 : longitudinal section through the autoinjector  1  and the detachable needle protection cap  100 , where in this figure the syringe  3  with needle guard  4  and the syringe holder  5  are also shown. 
         FIG. 4 a   : three-dimensional or perspective view of an alternative embodiment of a shell part  120 ′. 
         FIG. 4 b   : three-dimensional or perspective view of the alternative shell part  120 ′, placed on the housing  110 . 
         FIG. 5 a   : three-dimensional or perspective view of a further alternative embodiment of a shell part  120 ″, where the shell part in this case is cut. 
         FIG. 5 b   : three-dimensional or perspective view with partial section of the further alternative shell part  120 ″, placed on the housing  110 . The shell part is shown cut. 
     
    
    
     DETAILED DESCRIPTION 
     The following describes preferred embodiments of the detachable needle protection cap for injection devices, to which the invention could be applied, particularly to autoinjectors. In no way should this description be interpreted in a restrictive way, but should simply highlight possible embodiments. For example, the invention could also be used in other injection devices, such as the Ypsomed ServoPen® or the Novo Nordisk FlexPen®. 
     The mechanical part of the autoinjector  1  was omitted from the figures for reasons of clarity. The person skilled in the art is aware of well-known mechanisms, for example, from the applications WO2014/146209A1 or PCT/CH2016/000084, which are herein incorporated by reference in their entireties for any useful purpose. 
       FIGS. 1 to 3  show a first embodiment of the invention.  FIGS. 4 a  and 4 b    show an alternative embodiment of the shell parts; and  FIGS. 5 a  and 5 b    show a simplified form of the shell with only one shell part. 
       FIG. 1  shows the autoinjector  1  together with the fitted detachable needle protection cap  100  in a three-dimensional view. Two shell parts  120  can be seen, which surround the housing  110  (not visible in  FIG. 1 ) of the detachable needle protection cap  100 . The housing  110  cannot be seen in this state by the user. The external shape of the shells may vary as already mentioned, and in fact, it is the purpose of the invention to enable a variation of the external shape (i.e. of the geometric external design of the detachable needle protection cap, specifically of the shell parts). The shell parts  120  depicted here serve purely as an example. 
       FIG. 2  shows an exploded view of the detachable needle protection cap together with the housing  2  and the needle protection sleeve  6  of the autoinjector  1 . The other parts of the autoinjector  1  were left out, as indicated above. The housing  110  of the needle protection cap  100  comprises the recesses  110   a  into which the teeth  120   b  of the snap arms  120   a  can be engaged. The housing  110  also comprises the guide grooves  110   b , into which the guide ribs  120   c  can be pushed when the shell part  120  is pushed on. One shell part  120  also comprises the blocking elements  120   e . As mentioned, the shell parts  120  are individually fitted to the housing  110  when the detachable needle protection cap  100  is installed, by sliding the shell parts  120 ,  120  radially onto the housing  110 , where the guide ribs  120   c  are pushed into the guide grooves  110   b . Sliding-on of the shell parts  120 ,  120  is then complete when the teeth  120   b  engage in the recesses  110   a  of the housing  110  provided. Once an initial shell part  120  is installed, a second shell part  120  is pushed onto the opposite side of the housing  110 , in a similar way to the first shell part  120 . When the second shell part  120  snaps on to the housing  110 , the blocking elements  120   e  of the one shell part  120  also engage with the rear side of the free end of the snap arm  120   a  in the area of the tooth  120   b  of the other shell part  120  and vice-versa. The blocking elements  120   e  prevent the snap arms  120   a  from being deflected radially outwards (not shown in the figures), thus preventing the snap joint from becoming detached. 
       FIG. 3  shows a longitudinal section through the autoinjector  1  and the detachable needle protection cap  100 . This figure also shows the syringe  3  with glass body  3   a , the movable plug  3   b  and the injection needle  3   c , the needle guard  4  and the syringe holder  5  of the autoinjector  1 . What can also be seen is the front part of the needle protection sleeve  6  of the autoinjector  1  with the snap arm  6   a . Both shell parts  120  are installed onto the detachable needle protection cap  100 . It can be seen in this figure that the guide grooves  110   b  have undercuts  110   c . The guide ribs  120   c  also have a dovetail  120   d , which engages with the undercuts. The function of this embodiment is to minimize the radial mobility of the shell parts  120  in the assembled state and thus to give the combination of housing  110  and shell parts  120  maximum stability. In principle, the user should not notice that the detachable needle protection cap  100  is made up of several parts. The detachable needle protection cap  100  is inserted axially into the autoinjector  1 . In this case, the connection between the snap arm  6   a  of the needle protection sleeve  6  of the autoinjector  1  and the opening  110   h  of the housing  110  ensures that the detachable needle protection cap  100  remains on the autoinjector  1 , where this connection is detachable. On the housing  110 , two arms  110   f  protrude axially in the proximal direction. At their free end of the arms  110   f , teeth  110   g  are arranged, which face radially inward. As can be seen in  FIG. 3 , the teeth  110   g  are located behind the proximal end of the needle guard  4 . If the detachable needle protection cap  100  is now withdrawn distally from the autoinjector  1 , then the proximal end of the needle guard  4  and the teeth  110   g  engage. If the detachable needle protection cap  100  is further moved distally, the teeth  110   g  carry the needle guard  4  with them and detach it from the syringe  3 , thereby exposing the injection needle. 
       FIGS. 4 a  and 4 b    show the alternatively developed shell parts  120 ′. The design of the shell parts has been simplified. As with the shell parts of  FIGS. 1 to 3 , two shell parts are fitted to the housing  110  of the needle protection cap  100  (which is identical to that of  FIGS. 1 to 3 ). Before pushing on the shell parts, two shell parts  120 ′ are welded together along the weld seam which has been prepared with rib shapes and then pushed axially onto the housing  110  until the snap arms  110   i  are snap-fitted to the snap edge  120   a ′. In this case, when sliding the welded shell parts  120 ′, the guide ribs  120   c ′ are inserted into the guide grooves  110   k  provided. As in the examples of  FIGS. 1 to 3 , the guide grooves  110   k  also have undercuts (not shown) and the guide ribs  120   c ′ are dovetailed (not shown) so that after the shell parts  120 ′ are installed on the housing  110 , any movement of the shell parts  120 ′ in the radial direction relative to the housing  110  can be minimized. In the case of this embodiment too, the external geometry of the shells is merely an example because one aim of the invention is to allow different external shapes. 
       FIGS. 5 a  and 5 b    show a further simplification of the shell design by making two shell parts into one. Shell part  120 ″ is pot shaped. Instead of two shell parts, only one shell is used in this embodiment, which is pushed onto the housing  110  in an axial direction, where the housing  110  is identical to the previous embodiments. The function of guide ribs  120   c ″ and the guide grooves  100   k  is the same as in the example of  FIGS. 4 a  and 4 b   . The shell part  120 ″ is snapped over the snap edge  120   a ″ of the shell part  120 ″ and the snap teeth  110   j  of the housing  110 . 
     Another benefit of the invention described is the design of the housing  110 . As will be apparent to the person skilled in the art from the above description, the design of housing  110  described allows many different types of shell to be applied, without this entailing any change to the housing  110  design. 
     LIST OF REFERENCE NUMBERS 
     
         
         
           
               1  autoinjector 
               2  autoinjector housing 
               3  syringe 
               3   a  glass body 
               3   b  plug 
               3   c  injection needle or cannula 
               4  needle guard 
               5  syringe holder 
               6  needle protection sleeve of autoinjector 
               6   a  snap arm 
               100  detachable needle protection cap 
               110  housing 
               110   a  recess 
               110   b  guide groove 
               110   c  undercut 
               110   d  tooth 
               110   f  arm of detachable needle guard 
               110   g  tooth 
               110   h  opening 
               110   i  snap arm with tooth 
               110   j  axially directed snap tooth 
               110   k  guide groove with undercut 
               120  shell part 
               120   a  snap arm 
               120   b  tooth 
               120   c  guide rib 
               120   d  dovetail 
               120   e  blocking element 
               120 ′ alternative embodiment of the shell part 
               120   a ′ snap edge 
               120   e ′ ribbed preparation for weld 
               120   c ′ guide rib with dovetail 
               120 ″ further alternative embodiment of the shell part 
               120   a ″ snap edge 
               120   c ″ guide rib with dovetail.