Patent Publication Number: US-2021178083-A1

Title: Method and devices for receiving a cannula

Description:
RELATED APPLICATIONS 
     This application is a continuation of PCT/EP2019/071363, filed Aug. 8, 2019, which claims priority to EP 18 190 987.0, filed Aug. 27, 2018, the entire disclosures of both of which are hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     This disclosure relates to a cannula cartridge for receiving a cannula, a kit comprising the cannula cartridge and a method of manufacturing the cannula cartridge. The method and devices according to this disclosure may mainly be used when delivering medicine, such as, for example, insulin, to a user. This disclosure may both be applied in the field of home care as well as in the field of professional care, such as in hospitals and nursing homes. Other applications are generally feasible. 
     Delivering medicine to a user, specifically insulin delivery, plays an important role in the prevention and treatment of diseases, in particular in the treatment of diabetes mellitus. In medical therapy, when delivering medicine to a user on a regular basis, ambulatory infusion pumps such as medication pumps are widely used. In general, a cannula, such as an infusion cannula, is inserted into a body tissue of a user for the purpose of delivering medicine directly into the user&#39;s body, for example, via the medication pump. For hygienic and safety reasons such cannulas usually are single use objects and are therefore disposed right after use. 
     In general, cannulas pose a risk of injury. Therefore, as an example, single use inserter devices are used for insertion of a soft cannula into a body, preventing unintentional contact before and after insertion of the cannula. Such an inserter device may, for example, be known from EP 1 383 560 B1 disclosing a device for inserting a cannula into tissue, including a cannula, a protective element which can accommodate said cannula, an operating element for moving the cannula out of the protective element, and a holder fixedly connected to the cannula. This disclosure encompasses a system for connecting a liquid supply to the cannula. 
     Further, as an alternative, single use cannula cartridges for use in reusable inserters are known in the art, specifically for preventing unintentional contact with the cannula. As an example, WO 2009/001346 A1 discloses an insertion apparatus for use with a device for delivery of a therapeutic fluid into a body of a patient and/or for sensing of a bodily analyte. The apparatus includes a housing adapted for loading therein at least one cannula cartridge unit having a protective member. The protective member accommodates at least one penetrating cartridge having a subcutaneously insertable element and a penetrating member. The apparatus includes a displacement mechanism capable of protracting the penetrating cartridge towards the body of the patient, where protraction of the penetrating cartridge results in insertion of the subcutaneously insertable element into the body of the patient. 
     Despite the advantages involved in using such protection elements, e.g., single use inserter devices and cannula cartridges, several technical challenges remain. Specifically, high insertion forces generally lead to significant inconvenience for users and/or patients. Further, discard (scrap) rates, so far, in general are related to material induced safety issues. Thus, it is desirable to reduce material failure and fatigue, for example, caused by mechanical stress during transport and handling as well as long storage periods. 
     SUMMARY 
     This disclosure teaches methods and devices which address the above-mentioned technical challenges of cannula cartridges. Specifically, methods and devices shall be proposed providing a high degree of safety and reliability when handling and inserting the cannula, while still allowing for a compact and easy to use construction. 
     As used in the following, the terms “have,” “comprise” or “include” or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions “A has B,” “A comprises B” and “A includes B” may both refer to a situation in which, besides B, no other element is present in A (i.e., a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements. 
     Further, it shall be noted that the terms “at least one,” “one or more” or similar expressions indicating that a feature or element may be present once or more than once typically will be used only once when introducing the respective feature or element. In the following, in most cases, when referring to the respective feature or element, the expressions “at least one” or “one or more” will not be repeated, non-withstanding the fact that the respective feature or element may be present once or more than once. It shall also be understood for purposes of this disclosure and appended claims that, regardless of whether the phrases “one or more” or “at least one” precede an element or feature appearing in this disclosure or claims, such element or feature shall not receive a singular interpretation unless it is made explicit herein. By way of non-limiting example, the terms “cannula cartridge,” “inserter,” and “needle,” to name just a few, should be interpreted wherever they appear in this disclosure and claims to mean “at least one” or “one or more” regardless of whether they are introduced with the expressions “at least one” or “one or more.” All other terms used herein should be similarly interpreted unless it is made explicit that a singular interpretation is intended. 
     Further, as used in the following, the terms “preferably,” “more preferably,” “particularly,” “more particularly,” “specifically,” “more specifically” or similar terms are used in conjunction with optional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The disclosure may, as the skilled person will recognize, be performed by using alternative features. Similarly, features introduced by “in an embodiment of the invention” or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features. 
     In a first aspect of this disclosure, a cannula cartridge for receiving a cannula is disclosed. The term “cannula cartridge” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary protective device configured for housing the cannula. 
     The cannula cartridge comprises: 
     a) a needle unit (also referred to herein as “needle assembly”) having a needle hub and a needle attached to the needle hub;
 
b) a cannula, specifically a soft cannula; and
 
c) a protective element (also referred to herein as “protector”).
 
     The term “needle” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary elongated object having a sharp tip. In particular, the needle may have an elongated shape having a circular or oval profile and wherein a length of a longitudinal extension of the needle exceeds a diameter of the profile by at least 10 times. For example, the profile may change over the length of the needle. The needle may be or may comprise at least one solid and/or rigid material, such as a metal material, for example, steel. The needle may specifically comprise two ends or edges, wherein one end may be attached to the needle hub and the other end may comprise the sharp tip. The needle, specifically with the sharp tip, may, for example, be configured for piercing or puncturing a skin of the user. Specifically, the sharp tip may be slightly beveled, in particular the sharp tip may have at least one angled or chamfered side. 
     The term “needle hub” as used herein may specifically refer, without limitation, to an arbitrary connecting element attached or attachable to a needle. The needle hub may specifically be or may comprise means for applying force to the needle. The needle hub may at least partially have a cylindrical shape. Specifically, the needle hub may be of or may comprise at least one plastic material or polymer, such as a thermoplastic material or a thermosetting material, for example, acrylonitrile butadiene styrene (ABS) or polypropylene (PP). In particular, propylene may, for example, be used for being at least partially transparent, specifically for ultraviolet (UV) radiation or UV light, e.g., electromagnetic radiation having wavelengths in the range of 10 nm to 100 nm. Thus, in particular, the material of the needle hub may, for example, allow electromagnetic radiation, e.g., UV light, to pass through the material. For example, the passing of electromagnetic radiation may be beneficial for curing or hardening of UV curing adhesives, such as an adhesive generating a crosslinked network of, for example, polymers, when irradiated by UV light. 
     The term “cannula” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary fluidic element for conducting a liquid, which may be or may comprise a hollow tube or a hollow needle. The cannula may comprise a round profile, for example, the profile may have the shape of an O. Other shapes of the profile are also feasible. For example, the profile may change over the length of the cannula. The cannula may have two opposing ends. The cannula may particularly be configured to establish a fluid connection between the two opposing ends of the cannula. Specifically, the hollow profile of the cannula may complement the profile of the needle, such that the needle may be an exact fit into or through the cannula. In particular, the cannula may be slid on the needle. 
     The needle unit is movable within the protective element from at least one first position to at least one second position and vice a versa. In the first position the needle is covered by the protective element and in the second position the needle at least partially extends from the protective element. 
     The term “protective element”, or “protector”, as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary object having a protection space and configured to cover or shield an arbitrary element held within the protected space. Specifically, in the first position the needle unit may be held within the protected space of the protective element and thus, in the first position the needle unit may be covered by the protective element. The protective element may specifically be made of or may comprise at least one plastic material or polymer, such as a thermoplastic material or a thermosetting material, for example, acrylonitrile butadiene styrene (ABS) or polypropylene (PP). In particular, the protective element may specifically be made of or may comprise a material having a friction coefficient μ of 0.005≤μ≤0.5, specifically 0.01≤μ≤0.45, more specifically 0.02≤μ≤0.3. 
     Additionally, in the first position a retaining member (also referred to herein as “retainer”) of the protective element engages with an engagement element of the needle hub by a form fit connection. The term “form fit connection” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an assembly of at least two objects via at least partially conforming shapes or outlines. Thus, the retaining member and the engagement element may each comprise at least one element, both having essentially complementary forms or shapes in order to engage by the form fit connection. As an example, the retaining member may show a protrusion or convexity where the engagement element may show an indentation or concavity, thus in order for the retaining member and the engagement element to connect by a form fit, the protrusion and the indentation may engage. 
     The needle unit is configured to be moved by an inserter from the first position to the second position and back to the first position in which the retaining member again engages with the engagement element of the needle hub. The term “inserter” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary system configured for inserting at least one object into an arbitrary element by guiding a movement of the at least one object. In particular, the inserter may be configured for inserting the cannula into a body tissue of a user. As an example, the cannula may be slid onto the needle, e.g., during an assembly of the cannula cartridge, and may be inserted into the body tissue of the user via the movement of the needle unit guided by the inserter. 
     The retaining member and the engagement element of the needle hub are configured such that a holding force of the retaining member is overcome by applying forces parallel to the axis of the needle. 
     Further, the retaining member may comprise a spring element. In particular, the spring element may, for example, be configured to elastically return to a starting or initial position after being deflected. The spring element specifically may contain an interlocking element configured to snap into a corresponding feature of the engagement element. Specifically, the interlocking element may be configured to form a form fit connection with the engagement element. 
     The engagement element may comprise at least one groove or indentation in the needle hub. In particular, the at least one groove of the engagement element may, for example, be a circumferential groove or narrow channel. Specifically, the circumferential groove or narrow channel, for example, an all-around indentation, of the needle hub may divide the engagement element into at least two parts, such as at least two halves. In particular, the needle hub may have an essentially cylindrical shape, with the circumferential groove dividing the needle hub into two halves, specifically, for example, forming the shape of a barbell or an hourglass shape. 
     The retaining member may, for example, contain at least one latch. In particular, the latch, for example, a protrusion, may be configured for engaging with at least one cavity of the engagement element, such as with the at least one indentation or groove of the engagement element. Specifically, the latch may be configured for at least partially engaging with the at least one cavity, for example, with the at least one groove in the outer surface of the engagement element, e.g., with the circumferential groove. Thus, as an example the latch of the retaining member may, for example, be configured for at least partially engaging with the circumferential groove of the engagement element. 
     In an engaged state, the latch may block a motion of the needle unit, for example, both in a first direction pointing from the first position to the second position and in a second direction being opposite to the first direction. In particular, in the engaged state, the latch may block a movement of the needle along an axis of the needle. Specifically, a movement in both directions along the axis of the needle may be blocked. 
     The latch may be configured such that the blocking of the motion in the first direction may be overcome by a first biasing force on the needle unit. The latch may further be configured such that the blocking of the motion in the second direction may be overcome by a second biasing force on the needle unit. 
     Further, the latch may comprise at least one latch arm. The latch arm may specifically be connected to a housing of the protective element at a fixed end. In addition, the latch arm may further have at least one free end configured to engage with the engagement element of the needle hub. 
     The free end of the latch arm may, for example, contain an interlocking element having at least two sloped surfaces configured for engaging the engagement element of the needle hub. In particular, the at least two sloped surfaces may have different slopes, specifically different absolute values of the slopes. As an example, the at least two sloped surfaces may comprise at least one first sloped surface interacting with at least one edge of the engagement element when the needle unit moves from the first position to the second position, and at least one second sloped surface interacting with at least one proximal edge of the needle hub when the needle unit moves back from the second position to the first position. 
     The free end of the latch arm may, for example, contain an interlocking element configured for engaging the engagement element of the needle hub, wherein the interlocking element and the engagement element of the needle hub together comprise at least two sloped surfaces. The at least two sloped surfaces comprise at least one first sloped surface slidably engaging the engagement element with the interlocking element when the needle unit moves from the first position to the second position, and at least one second sloped surface slidably engaging the engagement element with interlocking element when the needle unit moves back from the second position to the first position, such that by moving the needle unit from the first position to the second position, the form fit connection is unlocked and by moving the needle unit from the second position to the first position, the form fit connection is locked. The first sloped surface may be part of the engagement element or the interlocking element, respectively. Likewise, the second sloped surface may be part of the engagement element or the interlocking element, respectively. Each sloped surface interacts with a respective edge or surface of the respective other element so to form a form fit connection. For example, in an embodiment the interlocking element comprises the at least two sloped surfaces, the at least one first sloped surface interacting with at least one edge of the engagement element when the needle unit moves from the first position to the second position, and the at least one second sloped surface interacting with at least one proximal edge of the needle hub when the needle unit moves back from the second position to the first position, such that by moving the needle unit from the first position to the second position, the form fit connection is unlocked and by moving the needle unit from the second position to the first position, the form fit connection is locked. 
     Further, the interlocking element may contain a protrusion from the latch arm, wherein the sloped surfaces may, for example, be surfaces of the protrusion and may specifically be configured for interacting with different edges of the needle hub. 
     The latch arm may specifically extend in a direction parallel to the axis of the needle. Thus, a longitudinal side of the latch arm may, for example, be arranged parallel to a longitudinal extension direction of the needle, specifically parallel to the axis of the needle. The latch arm may, for example, be disposed in a slot within a housing of the protective element. In particular, the latch arm may be disposed in a slot extending up to a rim of the housing at a proximal end of the housing. 
     In particular, the latch, when the retaining member is engaged with the engagement element of the needle hub, may be in a relaxed state. Thus, in an engaged state, when the retaining member is engaged with the engagement element of the needle hub, the latch may specifically be in a non-deflected state. As an example, in the relaxed state, specifically in the non-deflected state, no tensions may occur within the latch due to deformation. Thus, in the relaxed state, no deformation of the latch may occur. In particular, the latch may be free of inner stress or strain. 
     A retaining force of the retaining element may, for example, be defined by an elasticity of the latch and at least one angle of the latch. In particular, the form or shape as well as the material properties of the latch may dictate or define the retaining force of the retaining element. 
     The protective element may specifically be a monolithic element. In particular, the monolithic element may, for example, be an injection molded piece. The protective element, specifically in case of being injection molded, may be at least partially made of a thermoplastic material, such as, for example, polypropylene or ABS. 
     The protective element may, for example, comprise at least one longitudinal slot extending parallel to the axis of the needle. Further, the protective element may, for example, comprise at least one handling tab extending from the housing of the protective element. In particular, the handling tab may be configured for providing a surface where a user may hold the protective element, specifically using his or her fingers. Further, the protective element may, at its distal end, comprise at least one receptacle for receiving a centering element on a pump holder. 
     The protective element may have a housing with a bore contained therein. In particular, the needle unit may be received within the bore in a linearly slidable fashion in a direction parallel to the axis of the needle. The bore may specifically be a cylindrical bore. 
     In the first position, a proximal rim of the needle hub may be essentially flush with an upper rim of the protective element. In particular, in the first position, the proximal rim of the needle hub, specifically the upper rim of the needle hub, may be arranged in the same plane as the upper rim of the protective element. In the second position a lower rim of the needle hub may be essentially flush with a distal rim of the protective element. Specifically, in the second position the lower rim of the needle hub, e.g., a distal rim of the needle hub, may be arranged in the same plane as the distal rim of the protective element. 
     Specifically, in the second position, the needle and the cannula may protrude or extend from the protective element such that the cannula may be at least partially inserted into an adjoining element or object, such as, for example, a body tissue of a user or patient. Thus, in the second position, a gap may exist between the lower rim of the needle hub and the distal rim of the protective element. As an example, the lower rim of the needle hub may, for example, be essentially flush with a surface of the adjoining element or object, in particular with a surface of the body tissue. 
     The protective element may further contain at least one securing element for preventing the needle unit from leaving the protective element in a direction from the second position to the first position. In particular, the protective element may contain at least one protrusion protruding from a proximal rim of a bore within the protective element, the bore receiving the needle unit. 
     The cannula may specifically comprise a soft tubular cannula received on the needle. Specifically, the cannula may be or may comprise at least one flexible material, for example, a flexible polymer material. In particular, the soft cannula may be received or slid onto the needle, in order to stabilize the soft cannula, specifically when inserting the cannula into the body tissue. The cannula may further comprise at least one cannula hub attached to the soft tubular cannula. 
     In a further aspect of this disclosure, a kit is disclosed. The kit comprises: 
     A) at least one cannula cartridge; and
 
B) at least one inserter for inserting the cannula into a body tissue.
 
     In particular, the at least one cannula cartridge may specifically be the cannula cartridge as indicated above or as further described below. Thus, for possible additional definitions and embodiments, reference may be made to the description given above. 
     The inserter comprises: 
     at least one inserter housing having at least one receptacle for receiving the cannula cartridge; and
 
at least one insertion actuator configured for driving the needle unit from the first position to the second position and back to the first position.
 
     The insertion actuator may be spring-driven. Thus, the insertion actuator may rely on a spring-driven mechanism for driving the needle unit from the first position to the second position and back to the first position. In particular, the insertion actuator may be triggered by a spring. 
     Further, the insertion actuator may comprise at least one driving element interlocking with the engagement element of the needle hub during driving the needle unit. The driving element may specifically contain a fork clasping the needle hub from at least two sides during driving the needle unit. 
     In particular, the engagement element of the needle hub may contain a circumferential groove, wherein the fork interlocks with the circumferential groove. Specifically, fork and retaining member may interact with the engagement element of the needle hub from opposing sides. 
     Additionally or alternatively however, the engagement element of the needle hub may comprise at least two indentations, such as separate indentations, for example, two symmetrically arranged indentations, wherein the fork may interlock with the at least two indentations. Thus, for example, the engagement element of the needle hub may, specifically additionally or alternatively to the at least one circumferential groove, comprise multiple indentations, wherein the form may interact with the engagement element of the needle hub via the at least two indentations from one side and wherein the retaining member may interact with the engagement element of the needle hub from an opposing side, for example, via at least one further indentation or groove in the needle hub. 
     The inserter may further comprise at least one actuating element, specifically a trigger, the actuating element being configured for being actuated by a user in order to initiate the insertion of the cannula into the body tissue. 
     The kit may further comprise: 
     C) at least one pump holder comprising:
 
at least one attachment surface for attachment to a body surface of the user, specifically having at least one adhesive element; and
 
at least one mounting surface opposing the attachment surface, the mounting surface having at least one mounting element for mounting either the inserter or a medication pump, specifically an insulin pump, to the pump holder.
 
     Further, the pump holder may comprise a base providing the attachment surface and the mounting surface on opposing sides. In particular, the base may have at least one opening disposed therein for providing passage for one or more of the needle or the cannula. 
     Further, the kit may comprise: 
     D) at least one medication pump mountable onto the pump holder, wherein the medication pump and the inserter may be interchangeably mounted to the pump holder. 
     In a further aspect of this disclosure, a method of manufacturing the cannula cartridge is disclosed. In particular, the cannula cartridge as indicated above or as further described below is manufactured by the method. The method comprises the steps disclosed in the following. The steps may specifically be performed in the given order. Still, a different order is possible. The method may comprise additional steps which are not mentioned. It is further possible to perform one or more or all of the method steps repeatedly. Further, two or more of the method steps may be performed simultaneously or in a timely overlapping fashion. 
     The method comprises the following steps: 
     i. providing the needle unit;
 
ii. providing the cannula;
 
iii. providing the protective element;
 
iv. mounting the cannula to the needle of the needle unit;
 
v. inserting the needle unit with the cannula disposed thereon into the protective element, in a direction such that the needle of the needle unit is inserted ahead.
 
     The devices and methods according to this disclosure may provide a large number of advantages over known methods and devices. In particular, the disclosed cannula cartridge and the kit may further improve the security of handling and using the devices. Specifically, an impact of manufacturing tolerances and temperature effects on the safety of handling and using the disclosed devices may be reduced compared to known methods and devices. Thus, in particular, discard (scrap) rates due to material related safety issues may be minimized, and manufacturing yield may be increased. For example, in the proposed devices and methods, material failure and fatigue caused by mechanical stress during transport and handling as well as long storage periods, may be significantly reduced compared to known methods and devices. 
     Further, the devices and methods suggested in this disclosure may improve a production process of the proposed devices. In particular, the production of the proposed devices may be more economical due to a decrease of discard (scrap) rates compared to methods and devices known from the art. Furthermore, a decrease of the discard (scrap) rates may also lead to a more efficient use of resources. Thus, the devices and methods according to this disclosure may further show a higher degree of environmental compatibility than known methods and devices. 
     Further, the reliability of the devices and methods may be increased. Thus, as an example, the use of the engagement element and the retaining member may be used for replacing force-fit connections such as press-fit or interference-fit connections for holding the needle unit in place. Press-fit or interference-fit connections are prone to be subject to manufacturing tolerance issues and, thus, may create reliability issues. By using the engagement element and the retaining member, as described above, these issues may be avoided, and precision and reproducibility of the insertion process may be improved. 
     In addition, the proposed methods and devices may significantly lessen a user&#39;s or patient&#39;s inconvenience compared to known methods and devices, when inserting the cannula into the body tissue of the user. In particular, the cannula cartridge and the kit as disclosed herein may, for example, allow an insertion of the cannula with lower insertion forces than devices known in the art. 
     Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged: 
     Embodiment 1: A cannula cartridge for receiving a cannula, comprising: 
     a) a needle unit having a needle hub and a needle attached to the needle hub;
 
b) a cannula, specifically a soft cannula; and
 
c) a protective element,
 
wherein the needle unit is movable within the protective element from at least one first position to at least one second position and vice a versa,
 
wherein in the first position the needle is covered by the protective element,
 
wherein in the second position the needle at least partially extends from the protective element,
 
wherein in the first position a retaining member of the protective element engages with an engagement element of the needle hub by a form fit connection,
 
wherein the needle unit is configured to be moved by an inserter from the first position to the second position and back to a the first position in which the retaining member again engages with the engagement element of the needle hub,
 
wherein the retaining member and the engagement element of the needle hub are configured such that a holding force of the retaining member is overcome by applying forces parallel to the axis of the needle.
 
     Embodiment 2: The cannula cartridge according to any one of the preceding embodiments, wherein the retaining member comprises a spring element. 
     Embodiment 3: The cannula cartridge according to the preceding embodiment, wherein the spring element contains an interlocking element configured to snap into a corresponding feature of the engagement element. 
     Embodiment 4: The cannula cartridge according to any one of the preceding embodiments, wherein the engagement element comprises a circumferential groove in the needle hub. 
     Embodiment 5: The cannula cartridge according to the preceding embodiment, wherein the needle hub has an essentially cylindrical shape, with the circumferential groove dividing the needle hub into two halves, specifically forming the shape of a barbell. 
     Embodiment 6: The cannula cartridge according to any one of the preceding embodiments, wherein the retaining member contains at least one latch. 
     Embodiment 7: The cannula cartridge according to the preceding embodiment, wherein the latch is configured to engage with at least one cavity in at least one surface of the engagement element. 
     Embodiment 8: The cannula cartridge according to the preceding embodiment, wherein the cavity forms at least one circumferential groove in the surface of the engagement element. 
     Embodiment 9: The cannula cartridge according to any one of the three preceding embodiments, wherein, in an engaged state, the latch blocks a motion of the needle unit both in a first direction pointing from the first position to the second position and in a second direction being opposite to the first direction. 
     Embodiment 10: The cannula cartridge according to the preceding embodiment, wherein the latch is configured such that the blocking of the motion in the first direction is overcome by a first biasing force on the needle unit, wherein the blocking of the motion in the second direction is overcome by a second biasing force on the needle unit. 
     Embodiment 11: The cannula cartridge according to any one of the five preceding embodiments, wherein the latch comprises at least one latch arm, the latch arm being connected to a housing of the protective element at a fixed end, the latch arm further having at least one free end configured to engage with the engagement element of the needle hub. 
     Embodiment 12: The cannula cartridge according to the preceding embodiment, wherein the free end contains an interlocking element having at least two sloped surfaces configured for engaging the engagement element of the needle hub. 
     Embodiment 13: The cannula cartridge according to the preceding embodiment, wherein the at least two sloped surfaces have different slopes, specifically different absolute values of the slopes. 
     Embodiment 14: The cannula cartridge according to any one of the two preceding embodiments, wherein the at least two sloped surfaces comprise at least one first sloped surface interacting with at least one edge of the engagement element when the needle unit moves from the first position to the second position, and at least one second sloped surface interacting with at least one proximal edge of the needle hub when the needle unit moves back from the second position to the first position. 
     Embodiment 15: The cannula cartridge according to any one of the three preceding embodiments, wherein the interlocking element contains a protrusion from the latch arm, the sloped surfaces being surfaces of the protrusion, the sloped surfaces being configured for interacting with different edges of the needle hub. 
     Embodiment 16: The cannula cartridge according to any one of the five preceding embodiments, wherein the latch arm extends in a direction parallel to the axis of the needle. 
     Embodiment 17: The cannula cartridge according to any one of the six preceding embodiments, wherein the latch arm is disposed in a slot within a housing of the protective element, the slot extending up to a rim of the housing at a proximal end of the housing. 
     Embodiment 18: The cannula cartridge according to any one of the eleven preceding embodiments, wherein the latch, when the retaining member is engaged with the engagement element of the needle hub, is in a relaxed state, specifically in a non-deflected state. 
     Embodiment 19: The cannula cartridge according to any one of the twelve preceding embodiments, wherein a retaining force of the retaining element is defined by an elasticity of the latch and at least one angle of the latch. 
     Embodiment 20: The cannula cartridge according to any one of the preceding embodiments, wherein the protective element is a monolithic element. 
     Embodiment 21: The cannula cartridge according to the preceding embodiment, wherein the monolithic element is an injection molded piece. 
     Embodiment 22: The cannula cartridge according to any one of the preceding embodiment, wherein the protective element at least partially is made of polypropylene. 
     Embodiment 23: The cannula cartridge according to any one of the preceding embodiments, wherein the protective element contains at least one longitudinal slot extending parallel to the axis of the needle. 
     Embodiment 24: The cannula cartridge according to any one of the preceding embodiments, wherein the protective element comprises at least one handling tab extending from the housing of the protective element. 
     Embodiment 25: The cannula cartridge according to any one of the preceding embodiments, wherein the protective element comprises, at its distal end, at least one receptacle for receiving a centering element on a pump holder. 
     Embodiment 26: The cannula cartridge according to any one of the preceding embodiments, wherein the protective element has a housing with a bore contained therein, wherein the needle unit is received within the bore in a linearly slidable fashion in a direction parallel to the axis of the needle. 
     Embodiment 27: The cannula cartridge according to the preceding embodiment, wherein the bore is a cylindrical bore. 
     Embodiment 28: The cannula cartridge according to any one of the preceding embodiments, wherein in the first position a proximal rim of the needle hub is essentially flush with an upper rim of the protective element, and wherein in the second position a lower rim of the needle hub is essentially flush with a distal rim of the protective element. 
     Embodiment 29: The cannula cartridge according to any one of the preceding embodiments, wherein the protective element contains at least one securing element for preventing the needle unit from leaving the protective element in a direction from the second position to the first position. 
     Embodiment 30: The cannula cartridge according to the preceding embodiment, wherein the protective element contains at least one protrusion protruding from a proximal rim of a bore within the protective element, the bore receiving the needle unit. 
     Embodiment 31: The cannula cartridge according to any one of the preceding embodiments, wherein the cannula comprises a soft tubular cannula received on the needle. 
     Embodiment 32: The cannula cartridge according to the preceding embodiment, wherein the cannula further comprises at least one cannula hub attached to the soft tubular cannula. 
     Embodiment 33: A cannula cartridge ( 112 ) for receiving a cannula ( 114 ), comprising: 
     a) a needle unit ( 126 ) having a needle hub ( 128 ) and a needle ( 130 ) attached to the needle hub ( 128 );
 
b) a cannula ( 114 ); and
 
c) a protective element ( 132 ),
 
     wherein the needle unit ( 126 ) is movable within the protective element ( 132 ) in a direction parallel to the longitudinal axis of the needle from at least one first position to at least one second position and vice a versa, 
     wherein in the first position the needle ( 130 ) is covered by the protective element ( 132 ), 
     wherein in the second position the needle ( 130 ) at least partially extends from the protective element ( 132 ), 
     wherein in the first position a retaining member ( 134 ) of the protective element ( 132 ) engages with an engagement element ( 136 ) of the needle hub ( 128 ) by a form fit connection, 
     wherein the needle unit ( 126 ) is configured to be moved by an inserter ( 116 ) from the first position to the second position and back to a the first position in which the retaining member ( 134 ) again engages with the engagement element ( 136 ) of the needle hub ( 128 ), 
     wherein the retaining member ( 134 ) contains at least one latch ( 158 ), 
     the latch ( 158 ) comprises at least one latch arm ( 160 ), the latch arm ( 160 ) being connected to a housing ( 162 ) of the protective element ( 132 ) at a fixed end ( 164 ), the latch arm ( 160 ) further having at least one free end ( 166 ) configured to engage with the engagement element ( 136 ) of the needle hub ( 128 ), 
     wherein the free end ( 166 ) contains an interlocking element ( 168 ) configured for engaging the engagement element ( 136 ) of the needle hub ( 128 ), 
     wherein the interlocking element ( 168 ) and the engagement element of the needle hub ( 128 ) together comprise at least two sloped surfaces ( 170 ,  172 ), the at least two sloped surfaces ( 170 ,  172 ) comprise at least one first sloped surface ( 170 ) slidably engaging the engagement element ( 136 ) with the interlocking element ( 168 ) when the needle unit ( 126 ) moves from the first position to the second position, and at least one second sloped surface ( 172 ) slidably engaging the engagement element ( 136 ) with the interlocking element ( 168 ) when the needle unit ( 126 ) moves back from the second position to the first position, such that by moving the needle unit ( 126 ) from the first position to the second position the form fit connection is unlocked and by moving the needle unit ( 126 ) from the second position to the first position the form fit connection is locked. 
     Embodiment 34: The cannula cartridge ( 112 ) according to embodiment  33 , wherein the interlocking element ( 168 ) comprises the at least two sloped surfaces ( 170 ,  172 ), the at least one first sloped surface ( 170 ) interacting with at least one edge ( 174 ) of the engagement element ( 136 ) when the needle unit ( 126 ) moves from the first position to the second position, and the at least one second sloped surface ( 172 ) interacting with at least one proximal edge ( 176 ) of the needle hub, when the needle unit moves back from the second position to the first position, such that by moving the needle unit ( 126 ) from the first position to the second position the form fit connection is unlocked and by moving the needle unit ( 126 ) from the second position to the first position the form fit connection is locked. 
     Embodiment 35: A kit comprising: 
     A) at least one cannula cartridge according to any one of the preceding embodiments; and
 
B) at least one inserter for inserting the cannula into a body tissue, the inserter comprising:
 
at least one inserter housing having at least one receptacle for receiving the cannula cartridge; and
 
at least one insertion actuator configured for driving the needle unit from the first position to the second position and back to the first position.
 
     Embodiment 36: The kit according to the preceding embodiment, wherein the insertion actuator is spring-driven. 
     Embodiment 37: The kit according to any one of the two preceding embodiments, wherein the insertion actuator comprises at least one driving element interlocking with the engagement element of the needle hub during driving the needle unit. 
     Embodiment 38: The kit according to the preceding embodiment, wherein the driving element contains a fork clasping the needle hub from at least two sides during driving the needle unit. 
     Embodiment 39: The kit according to the preceding embodiment, wherein the engagement element of the needle hub contains a circumferential groove, wherein the fork interlocks with the circumferential groove. 
     Embodiment 40: The kit according to the preceding embodiment, wherein fork and retaining member interact with the engagement element of the needle hub from opposing sides. 
     Embodiment 41: The kit according to any one of the preceding embodiments referring to a kit, wherein the inserter further comprises at least one actuating element, specifically a trigger, the actuating element being configured for being actuated by a user in order to initiate the insertion of the cannula into the body tissue. 
     Embodiment 42: The kit according to any one of the preceding embodiments referring to a kit, wherein the kit further comprises: 
     C) at least one pump holder comprising:
 
at least one attachment surface for attachment to a body surface of the user, specifically having at least one adhesive element; and
 
at least one mounting surface opposing the attachment surface, the mounting surface having at least one mounting element for mounting either the inserter or a medication pump, specifically an insulin pump, to the pump holder.
 
     Embodiment 43: The kit according to the preceding embodiment, wherein the pump holder comprises a base providing the attachment surface and the mounting surface on opposing sides, the base having at least one opening disposed therein for providing passage for one or more of the needle or the cannula. 
     Embodiment 44: The kit according to any one of the two preceding embodiments, the kit further comprising: 
     D) at least one medication pump mountable onto the pump holder, wherein the medication pump and the inserter are interchangeably mountable to the pump holder. 
     Embodiment 45: A method of manufacturing the cannula cartridge according to any one of the preceding embodiments referring to a cannula cartridge, the method comprising: 
     i. providing the needle unit;
 
ii. providing the cannula;
 
iii. providing the protective element;
 
iv. mounting the cannula to the needle of the needle unit;
 
v. inserting the needle unit with the cannula disposed thereon into the protective element, in a direction such that the needle of the needle unit is inserted ahead.
 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  shows a perspective view of an embodiment of a kit comprising an embodiment of a cannula cartridge; 
         FIG. 2  shows an embodiment of a cannula cartridge in a perspective view; 
         FIGS. 3A and 3B  show section views of an embodiment of a cannula cartridge with the needle unit and the cannula in a first position ( FIG. 3A ) and in a second position ( FIG. 3B ); 
         FIG. 4  shows a detail of an embodiment of a cannula cartridge; and 
         FIG. 5  shows a flow chart of an embodiment of a method of manufacturing a cannula cartridge. 
     
    
    
     DESCRIPTION 
     The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure. 
       FIG. 1  shows a perspective view of an embodiment of a kit  110  comprising at least one cannula cartridge  112  for receiving a cannula  114 . The kit  110  further comprises at least one inserter  116  for inserting the cannula  114  into a body tissue  118 . The inserter  116  comprises at least one inserter housing  120  having at least one receptacle  122  for receiving the cannula cartridge  112  and at least one insertion actuator  124 . 
       FIG. 2  shows an embodiment of the cannula cartridge  112  comprising the cannula  114  and a needle unit (also referred to as a “needle assembly”)  126  having a needle hub  128  and a needle  130  attached to the needle hub  128 . In particular, the cannula  114 , for example, a soft cannula  114 , may be mounted to the needle  130  of the needle unit  126 . Specifically, the cannula  114  may be slid onto the needle  130 . The cannula cartridge  112  further comprises a protective element  132 , also referred to as a “protector”. 
     In particular, the needle unit  126  is movable within the protective element from at least one first position, as, for example, illustrated in  FIG. 3A , to at least one second position, as, for example, illustrated in  FIG. 3B , and vice versa. As shown in  FIG. 3A , in the first position the needle  130  is covered by the protective element  132 . As shown in  FIG. 3B , in the second position the needle  130  at least partially extends from the protective element  132 . In the first position a retaining member (also referred to as a “retainer”)  134  of the protective element  132  engages with an engagement element  136  of the needle hub  128  by a form fit connection. 
     The needle unit  126  is configured to be moved by an inserter  116  from the first position to the second position and back to the first position in which the retaining member  134  again engages with the engagement element  136  of the needle hub  128 . Further, the retaining member  134  and the engagement element  136  of the needle hub  128  are configured such that a holding force of the retaining member  134  is overcome by applying forces parallel to the axis  138  of the needle  130 . 
     In particular, the insertion actuator  124  as illustrated in  FIG. 1  is configured for driving the needle unit  126  from the first position to the second position and back to the first position. The insertion actuator  124  may, for example, be spring driven and may, for example, comprise at least one driving element (also referred to as a “driver”)  140  interlocking with the engagement element  136  of the needle hub  128  during driving the needle unit  128 . Specifically, as illustrated in  FIGS. 3A and 3B , the driving element  140  may comprise a fork  142  clasping the needle hub  128  from at least two sides during driving the needle unit  126 . In particular, the needle hub  128  may comprise at least one circumferential groove  144 , wherein the fork  142  may interlock with the circumferential groove  144 . As illustrated in the figures, the fork  142  and the retaining member  134  may interact with the engagement element  136  of the needle hub  128  from opposing sides. 
     In particular,  FIG. 3B , may specifically illustrate an optional embodiment of the cannula cartridge  112  with the needle unit  126  and the cannula  114  in the second position. Specifically the positioning of the needle unit  126  and the cannula  114  in the second position may differ from the illustrated arrangement. For example, the needle unit  126  and the cannula  114  may, in the second position, be arranged such that a lower rim of the needle hub  128  may be essentially flush to either a distal rim of the protective element  132  or a surface of the body tissue  118 . However, other arrangements are feasible. Specifically, in the second position, the needle  130  and the cannula  114  may protrude or extend from the protective element  132  such that the cannula  114  may be at least partially inserted into the body tissue  118 . Thus, as an example, in the second position, a gap may exist between the lower rim of the needle hub  128  and the distal rim of the protective element  132 . 
     As illustrated in  FIG. 1 , the inserter  116  may further comprise at least one actuating element  146 , specifically a trigger  148 . The actuating element (also referred to as an “actuator”)  146  may, for example, be configured for being actuated in order to initiate the insertion of the cannula  114  into the body tissue  118 . Specifically, the actuating element  146  may be configured for being activated by a user. Alternatively however, the actuation element  146  may, for example, be configured for being activated by a press-force, such as a force occurring when positioning the inserter on top of the body tissue  118 . Thus, as an example, the press-force may activate the actuation element  146  in the event of the inserter  116  being positioned relative to the body tissue  118 . As further illustrated in  FIG. 1 , the kit  110  may comprise at least one pump holder  150 . In particular, the pump holder  150  may comprise at least one attachment surface  152  for attachment to a body surface of the user, such as to a surface of the body tissue  118  of the user. The attachment surface  152  may, for example, have at least one adhesive element. The pump holder  150  may further comprise at least one mounting surface  154  opposing the attachment surface  152 . Specifically, the mounting surface  154  may have at least one mounting element  156  for mounting either the inserter  116  or a medication pump (not shown), specifically an insulin pump, to the pump holder  150 . 
       FIG. 4  shows an embodiment of a detail of an embodiment of a cannula cartridge, specifically a detail of the embodiment of the cannula cartridge as illustrated in  FIG. 2 . As illustrated, the needle hub  128  may have a cylindrical shape, wherein as an example, the engagement element  136  of the needle hub  128 , specifically the circumferential groove  144  of the engagement element  136 , may divide the needle hub  128  into two halves. Thus, the circumferential groove  144  of the engagement element  136  may, for example, form the needle hub  128  into the shape of a barbell. In  FIG. 4 , the needle unit  126  is illustrated in the first position, thus the engagement element  136  of the needle hub  128  in  FIG. 2  is engaged with the retaining member  134  of the protective element  132  by a form fit connection. As illustrated, the retaining member  134  may comprise at least one latch  158 , wherein the latch  158  may be configured to engage with at least one cavity in at least one surface of the engagement element  136 , such as with the circumferential groove  144 . In particular, the latch  158  may comprise at least one latch arm  160 , for example, extending in a direction parallel to the axis  138  of the needle  130 . The latch arm  160  may specifically be connected to a housing  162  of the protective element  132  at a fixed end  164 . Further, the latch arm  160  may have at least one free end  166  configured to engage with the engagement element  136  of the needle hub  128 . As an example, the free end  166  may contain an interlocking element  168  having at least a first sloped surface  170  and a second sloped surface  172  for engaging the engagement element  136 . The at least two sloped surfaces  170 ,  172  may specifically have different slopes, in particular different absolute values of the slopes. For example, the first sloped surface  170  may interact with at least one edge  174  of the engagement element  136  when the needle unit  126  moves from the first position to the second position. The second sloped surface  172  on the other hand, may interact with at least one proximal edge  176  of the needle hub  126  when the needle unit  126  moves back from the second position to the first position. Further, the second sloped surface  172  may additionally interact with at least one lower edge  175  of the engagement element  136 , specifically as an example, in order to keep the needle unit  126  from leaving the protective element  132 . In particular, the latch arm  160  may be disposed in a slot within the housing  162  of the protective element  132 , wherein the slot may extend up to a rim  178  of the housing  162  at a proximal end  180  of the housing  162 . The latch arm  160  may specifically be in a relaxed state, for example, in a non-deflected state, when the retaining member  134  is engaged with the engagement element  136  of the needle hub  128 . 
     As an example, in the first position, the latch  158  may keep the needle hub  128 , specifically the needle unit  126  having the cannula  114  mounted thereon, in place, in particular by the interlocking element  168  with its two sloped surfaces  170 ,  172  for engaging the engagement element  136 . The latch  158  itself may, specifically in the first position, be in a relaxed or tension-free state. Thus, no material deformation due to stress and/or strain may occur in the latch  158  in the first position. A retaining force of the retaining member  134 , specifically of a retaining element or the latch  158 , may be defined by an elasticity of the latch  158  and at least one angle of the latch, in particular by the first sloped surface  170  and/or the second sloped surface  172 . Further, the retaining force may depend on a material combination, specifically on at least one friction coefficient, of the latch  158  and the needle hub  128 . A movement or shift of the needle unit  126  from the first position in the direction of the second position along the axis  138  of the needle  130  may specifically require overpowering the retaining force. In case the retaining force is overpowered, specifically the latch  158  may be deflected such that the needle unit  126  may be slidable from the first position in the direction towards the second position. The latch  158  may return to a non-deflected state after the needle hub  128  has, for example, passed the latch  158 . 
       FIG. 5  shows a flow chart of an embodiment of a method of manufacturing a cannula cartridge  112 . The method comprises the following steps: 
     i. (denoted with reference number  182 ) providing the needle unit  126 ;
 
ii. (denoted with reference number  184 ) providing the cannula  114 ;
 
iii. (denoted with reference number  186 ) providing the protective element  132 ;
 
iv. (denoted with reference number  188 ) mounting the cannula  114  to the needle  130  of the needle unit  126 ;
 
v. (denoted with reference number  190 ) inserting the needle unit  126  with the cannula  114  disposed thereon into the protective element  132 , in a direction such that the needle  130  of the needle unit  126  is inserted ahead.
 
     While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims. 
     LIST OF REFERENCE NUMBERS 
     
         
           110  Kit 
           112  cannula cartridge 
           114  Cannula 
           116  Inserter 
           118  body tissue 
           120  inserter housing 
           122  Receptacle 
           124  insertion actuator 
           126  needle unit 
           128  needle hub 
           130  needle 
           132  protective element 
           134  retaining member 
           136  engagement element 
           138  Axis 
           140  driving element 
           142  Fork 
           144  circumferential groove 
           146  actuating element 
           148  Trigger 
           150  pump holder 
           152  attachment surface 
           154  mounting surface 
           156  mounting element 
           158  Latch 
           160  latch arm 
           162  Housing 
           164  fixed end 
           166  free end 
           168  interlocking element 
           170  first sloped surface 
           172  second sloped surface 
           174  Edge 
           175  lower edge 
           176  proximal edge 
           178  Rim 
           180  proximal end 
           182  step i.: providing the needle unit 
           184  step ii.: providing the cannula 
           186  step iii.: providing the protective element 
           188  step iv.: mounting the cannula to the needle of the needle unit 
           190  step v.: inserting the needle unit with the cannula disposed thereon into the protective element, in a direction such that the needle of the needle unit is inserted ahead