Needle cap with undercut

Abstract

The invention relates to a needle cap with an undercut. A needle cap for protecting a needle mounted on a tip of a cartridge of a medical injection device may include an inner shield, and an outer shield at least partially surrounding the inner shield and secured to the inner shield, where the needle cap may include the outer shield, the outer shield including: a main body, the main body comprises a first open end, a second end and a side wall extending between the first end and the second end, and the main body defines a cavity for receiving the inner shield therein; a first undercut is defined proximate the first open end of the body.

Description

[0001] This divisional application is based on the Chinese patent application with application number 202080031411.0, application date April 24, 2020, and invention name “Needle cap with undercut”. This Chinese patent application is the Chinese national phase of the international application with international application number PCT / EP2020 / 061485. Technical Field

[0002] The present disclosure generally relates to a medical injection device for delivering fluid or liquid medicine. More specifically, the present disclosure relates to a needle cap adapted to be mounted on a distal end of the medical injection device for covering a needle attached thereto. The present disclosure also relates to a medical assembly comprising a medical injection device and a needle cap for enclosing the needle of the medical injection device. Background Art

[0003] Medical injection devices such as syringes are well known in the art. These devices typically include a container for containing a medical composition such as a liquid drug. The container typically includes an end piece in the form of a longitudinal end, which defines a fluid path through which the medical solution is discharged. A needle can be attached to the end in order to pierce the patient's skin and perform an injection of the medical composition.

[0004] In order to maintain sterility before use and reduce the risk of causing accidental needle sticks, protection of the needle is important. Therefore, a needle cap can be mounted on the end of the barrel to enclose the needle. This makes the needle physically inaccessible to people around the device. The needle cap may include an inner shield made of a material having elastomeric properties, and may also include an outer shield made of a rigid plastic surrounding the inner shield. The inner needle shield ensures the sealing of the medical injection device. To this end, the inner needle shield includes a sealing portion that is in sealing contact with the outer surface of the syringe end to provide a tight seal. The inner needle shield prevents any contamination of the medical composition by the external environment, thereby ensuring the integrity of the container package. The inner needle shield further prevents any leakage of the composition from the outlet of the needle to the external environment. To this end, the needle is preferably pierced in the inner needle shield.

[0005] Immediately before use, the user has to remove the protective needle cap from a medical injection device. The force required to remove the needle cap is measured by a physical parameter called "pull-out force" (also called "POF"). The pull-out force required to remove a known needle cap from an injection device, such as a syringe, can be very high and is due in particular to the friction between the inner needle shield and the tip due to the pressure exerted by the inner needle shield on the tip.

[0006] As a result, a user with reduced strength, such as a user weakened by illness, may be unable to remove the needle shield and use the injection device for treatment.

[0007] Furthermore, healthcare professionals, such as nurses, who frequently use injection devices, are at high risk of injuring themselves, as they may not be able to control the force they apply to pull the needle cover off the injection device, which may result in uncontrolled and dangerous movements. Finally, due to the high required pull-out force, the needle of the syringe may bend during the removal of the needle cover. Summary of the invention

[0008] In view of the above problems, there is currently a need for a needle cap that allows for reducing the pull-out force required to remove the needle cap from a medical injection device without reducing the tight seal of the needle cap with the tip of the medical injection device (while keeping the non-leakage characteristics of the needle cap intact).

[0009] In one example of the present disclosure, a needle cap for protecting a needle mounted on the end of a barrel of a medical injection device, wherein the end extends from the distal end of the barrel, the needle cap may include an inner shield extending along a longitudinal axis, the inner shield including an inner proximal connecting element configured to sealingly contact the end of the barrel, and an outer shield at least partially surrounding the inner shield and fixed to the inner shield, wherein the outer shield of the needle cap may include: a body including a first open end, a second end and a side wall extending between the first end and the second end, the body defining a cavity for receiving the inner shield therein; and an undercut defined near the first open end of the body.

[0010] In another example of the present disclosure, the outer shield of the needle cap also includes a second undercut defined near the first open end of the body, wherein a longitudinal length of the first undercut extending from the first open end toward the second end is smaller than a longitudinal length of the second undercut extending from the first open end toward the second end.

[0011] In another example of the present disclosure, the distance from the first open end of the outer shield to the proximal edge of the first undercut present on the body of the outer shield is greater than the distance from the first open end of the outer shield to the proximal edge of the second undercut present on the body of the outer shield. The first locking tab may extend from the inner surface of the body of the outer shield close to the first undercut, and the second locking tab may extend from the inner surface of the body of the outer shield close to the second undercut. The circumferential width of the first locking tab may be greater than the circumferential width of the second locking tab. The first locking tab and the second locking tab may include proximal inclined surfaces. The difference between the distance from the first open end of the outer shield to the proximal edge of the first undercut and the distance from the first open end of the outer shield to the proximal edge of the second undercut may be at least 1 mm. The first undercut and the second undercut may be diametrically opposite to each other. The first undercut and the second undercut may be rectangular in shape.

[0012] In addition, the body may define at least one U-shaped groove on its outer surface. The U-shaped groove may include a distal wall and a proximal wall extending radially from the body. The distance from the first open end of the outer shield to the distal edge of the first undercut may be equal to the distance from the first open end of the outer shield to the distal edge of the second undercut.

[0013] In another example of the present disclosure, a medical assembly includes: a medical injection device, which includes: a barrel defining a reservoir suitable for containing a medical composition; a tip extending from a distal end surface of the barrel, the tip defining a fluid path extending through the tip and communicating with the reservoir fluid; a needle communicating with the reservoir; and a needle cap suitable for covering the needle; characterized in that: the needle cap includes: an inner shield extending along a longitudinal axis, the inner shield including an inner proximal connecting element configured to sealingly contact the tip of the barrel; and an outer shield covering at least a portion of the inner shield, the outer shield including: a body including a first open end, a second end and a side wall extending between the first end and the second end, the body defining a cavity for receiving the inner shield therein; and a first undercut defined near the first open end of the body.

[0014] Advantageously, the outer shield of the medical component further comprises a second undercut distinct from the first undercut and defined near the first open end of the body, wherein a longitudinal length of the first undercut extending from the first open end of the outer shield toward the second end of the outer shield is smaller than a longitudinal length of the second undercut extending from the first open end of the outer shield toward the second end of the outer shield.

[0015] The following terms also apply to this invention and disclosure:

[0016] Item 1: A needle cap for protecting a needle mounted on the end of a barrel of a medical injection device, wherein the end extends from the distal end of the barrel, the needle cap comprising: an inner shield extending along a longitudinal axis, the inner shield comprising an inner proximal connecting element configured to sealingly contact the end of the barrel; and an outer shield at least partially surrounding the inner shield and fixed to the inner shield, wherein the outer shield comprises: a body, the body comprising a first open end, a second end and a side wall extending between the first end and the second end, the body defining a cavity for receiving the inner shield therein; and a first undercut defined near the first open end of the body.

[0017] Item 2: A needle cap according to Item 1, wherein the body of the outer shield further comprises a second undercut defined near the first open end of the body, wherein a longitudinal length of the first undercut extending from the first open end toward the second end of the outer shield is less than a longitudinal length of the second undercut extending from the first open end toward the second end of the outer shield.

[0018] Clause 3: The needle cap according to clause 2, wherein a distance from the first open end to a proximal edge of the first undercut is greater than a distance from the first open end to a proximal edge of the second undercut.

[0019] Clause 4: The needle cap according to Clause 2, further comprising: a first locking tab extending from an inner surface of the body proximate the first undercut; and a second locking tab extending from an inner surface of the body proximate the second undercut.

[0020] Clause 5: The needle cap according to Clause 4, wherein a circumferential width of the first locking piece is greater than a circumferential width of the second locking piece.

[0021] Clause 6: The needle cap of Clause 4, wherein the first locking tab and the second locking tab comprise proximal inclined surfaces.

[0022] Clause 7: The needle cap according to Clause 2, wherein the difference between the distance from the first open end to the proximal edge of the first undercut and the distance from the first open end to the proximal edge of the second undercut is at least 1 mm.

[0023] Clause 8: The needle cap of Clause 2, wherein the first undercut and the second undercut are diametrically opposed to each other.

[0024] Clause 9: The needle cap of Clause 2, wherein the first undercut and the second undercut are rectangular in shape.

[0025] Clause 10: The needle cap of Clause 1, wherein the body defines at least one U-shaped groove on an outer surface thereof.

[0026] Clause 11: The needle cap of clause 10, wherein the U-shaped groove comprises a distal wall and a proximal wall extending radially from the body.

[0027] Clause 12: The needle cap of Clause 2, wherein a distance from the first open end to a distal edge of the first undercut is equal to a distance from the first open end to a distal edge of the second undercut.

[0028] Item 13: A needle cap according to Item 2, wherein the outer shield is fixed to the inner shield by a snap-fit ​​connection, and the inner proximal connecting element of the inner shield is inserted into the first undercut and the second undercut of the outer shield to form a snap-fit ​​connection, so that when a pulling force is applied to the outer shield in the distal direction, the inner shield first contacts the end surface of the first undercut and then contacts the end surface of the second undercut, thereby bending the inner shield in the radial direction to help the inner shield to disengage from the distal end.

[0029] Item 14: A medical assembly, comprising: a medical injection device, comprising: a barrel defining a reservoir suitable for containing a medical composition; a tip extending from a distal end surface of the barrel, which defines a fluid path extending through the tip and connected to the reservoir fluid; a needle connected to the reservoir; and a needle cap according to any one of Items 1 to 12, which is suitable for covering the needle; characterized in that: the needle cap comprises: an inner shield extending along a longitudinal axis, which includes an inner proximal connecting element configured to sealingly contact the tip of the barrel; an outer shield covering at least a portion of the inner shield, the outer shield comprising: a body, the body including a first open end, a second end and a side wall extending between the first end and the second end, the body defining a cavity for receiving the inner shield therein; and a first undercut defined near the first open end of the body.

[0030] Clause 15: The medical assembly of Clause 14, wherein the tip and barrel of the medical injection device are made of glass. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above and other features and advantages of the present disclosure and the manner of achieving them will become more apparent, and the present disclosure itself will be better understood, through the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0032] Figure 1 is a perspective view of a medical injection device according to an embodiment of the present invention;

[0033] Figure 2 A needle cap according to an embodiment of the present invention Figure 1 A perspective view of a medical injection device;

[0034] Figure 3 is a front view of a needle cap according to an embodiment of the present invention;

[0035] Figure 4 yes Figure 3 An isolated perspective view of a needle cap;

[0036] Figure 5 yes Figure 3 A cross-sectional view of a proximal portion of a needle cap;

[0037] Figure 6 yes Figure 3 An isolated perspective view of the proximal portion of the needle cap;

[0038] Figure 7 is a perspective view of an inner shield according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The following description is provided to ensure that those skilled in the art can make and use the described embodiments considered for implementing the present invention. However, various modifications, equivalents, variations and substitutions are still apparent to those skilled in the art. Any and all such modifications, variations, equivalents and substitutions are intended to fall within the spirit and scope of the present invention.

[0040] For purposes of the description hereinafter, the terms "upper", "lower", "right", "left", "vertical", "horizontal", "top", "bottom", "lateral", "longitudinal" and their derivatives shall relate to the present invention as it is oriented in the accompanying drawings. However, it should be understood that the present invention may employ a variety of alternative variations, unless expressly specified to the contrary. It should also be understood that the specific devices shown in the drawings and described in the following specification are merely exemplary embodiments of the present invention. Therefore, specific dimensions and other physical characteristics related to the embodiments disclosed herein should not be considered limiting.

[0041] In the following discussion, "distal" refers to the direction generally toward the end of the medical injection device suitable for contacting the patient's skin, and "proximal" refers to the direction opposite to the distal end, i.e., the end away from the medical injection device. In other words, the "distal direction" should be understood to mean the injection direction. The distal direction corresponds to the direction of travel of the plunger during injection, and the medical composition initially contained in the barrel is discharged from the barrel. The "proximal direction" should be understood as the direction opposite to the injection direction. For the purposes of the present disclosure, the above references are used in the description of the components of the medical injection device according to the present disclosure.

[0042] refer to Figure 1 , the medical injection device 10 includes a barrel 18 extending from a proximal face 36 to a distal face 34 along a longitudinal axis X, which defines a reservoir 20 for a medical composition such as a liquid drug. The medical injection device 10 may also include a stopper (not shown) and a plunger rod 26 having a flange 68, and the plunger rod may be translationally moved from a proximal position to a distal position within the barrel 18 for injecting the composition.

[0043] The medical injection device 10 also includes a distal tip 35 extending from the distal face 34 of the barrel 18 along the axis X. The distal tip 35 is at least partially hollow so as to form a fluid path in fluid communication with the barrel 18. The needle 14 can be attached to the distal tip 35 of the injection device 10 and in fluid communication with the fluid path. It should be noted here that the distal face 34 of the barrel 18 is close to the shoulder of the medical injection device.

[0044] The medical injection device 10 is preferably made of glass, and more preferably is a glass syringe. Such glass syringes are widely used in hospital environments and are easy to sterilize. The medical injection device 10 is preferably a pre-filled syringe. The medical injection device 10 is more preferably a syringe with a staked needle.

[0045] refer to Figure 2 The medical injection device further comprises a needle cap 100. The needle cap 100 shields and covers the needle 14. The needle cap 100 may comprise an outer shield 101 and an inner shield 30, the inner shield covering the needle 14 and being covered by the outer shield 101.

[0046] refer to Figure 3 , describes the outer shield 101 according to an embodiment of the present invention in more detail. The outer shield 101 is preferably made of a rigid material, such as a rigid plastic. The outer shield 101 can be made of medical grade plastic. The rigid material imparts rigidity to the outer shield 101, which allows the outer shield 101 to better protect the needle cap 100 from impact. The structural integrity of the needle cap 100 is thereby improved.

[0047] The outer shield 101 comprises a body 102 having a proximal end 104 and a distal end 106. The body 102 extends along a longitudinal axis Y. The axis Y coincides with the axis X when the needle cap 100 is mounted on the tip 35 of the medical injection device 10.

[0048] In one example, the body 102 can be substantially cylindrical in shape. The body 102 can define an inner cavity 108 (see Figure 6 ), the inner cavity at least partially receives the inner shield 30 of the medical injection device 10. The collar 110 can be formed on the proximal end 104 of the outer shield 101. The collar 110 can have a larger diameter than the rest of the body 102. In one example, a plurality of ribs 112 and grooves 114 can be defined on the body 102 of the outer shield 101. The ribs 112 and grooves 114 can be disposed near the distal end 106 of the outer shield 101. The ribs 112 and grooves 114 provide a gripping surface for a user to use when pulling the outer shield 101 away from the medical injection device 10.

[0049] exist Figure 3 and Figure 4 In another example shown, a U-shaped groove 116 can be formed in the side surface of the body 102 to create another feature to help the user pull the outer shield 101 away from the medical injection device 10. The U-shaped groove 116 includes a distal wall 118 and a proximal wall 119. The distal wall 118 of the U-shaped groove 116 allows the user to apply pressure to the outer shield 101 to generate a greater pulling force, thereby pulling the outer shield 101 away from the medical injection device 10. A plurality of ribs 112 and grooves 114 can be provided along the U-shaped groove 116.

[0050] refer to Figure 5, the collar 110 of the body 102 of the outer shield 101 may define at least one undercut, preferably at least one pair of undercuts 120, 122. In one example, the undercuts 120, 122 are holes extending through the outer shield 101. The presence of the undercuts 120, 122 allows for a reduction in the pull-out force required by a user to remove the outer shield 101 from the medical injection device 10, as described herein. The undercuts 120, 122 may also be referred to as "windows" extending through the collar 110. In fact, due to these windows, the user can visually ensure that the inner shield 30 is at least partially enclosed in the outer shield 101.

[0051] In one example, at least one of the undercuts 120, 122, preferably both undercuts 120, 122, can be substantially rectangular in shape. In one example, the undercuts 120, 122 can be diametrically opposite each other on the collar 110. The longitudinal length A of the first undercut 120 can be less than the longitudinal length B of the second undercut 122. The longitudinal length A can be measured from the proximal surface 124 of the first undercut 120 to the distal surface 126 of the first undercut 120. The longitudinal length B can be measured from the proximal surface 128 of the second undercut 122 to the distal surface 130 of the second undercut 122. In another example, the distance from the proximal end 104 of the body 102 to the distal surface 126 of the first undercut 120 is substantially equal to the distance from the proximal end 104 of the body 102 to the distal surface 130 of the second undercut 122. When the longitudinal lengths A, B of the undercuts 120, 122 are different from each other, the undercuts 120, 122 are considered to be asymmetric with each other. In another example, the distance from the proximal end 104 of the body 102 to the proximal surface 124 of the first undercut 120 is greater than the distance from the proximal end 104 of the body 102 to the proximal surface 128 of the second undercut 122. In one example, the undercuts 120, 122 are extruded from the collar 110 of the body 102. It is also contemplated that any other manufacturing method may be used to define the undercuts 120, 122 in the collar 110. Advantageously, the two undercuts 120, 122 are discrete from one another and define two distinct holes in the collar 110.

[0052] refer to Figure 6 , details another feature of the outer shield 101. In particular, two latching tabs 132, 134 can extend inwardly from the inner surface of the collar 110 near the proximal end 104 of the body 102. The latching tabs 132, 134 can include an inclined surface 136 that is angled relative to the longitudinal axis Y of the outer shield 101, and a substantially planar surface 138 that extends parallel to the longitudinal axis Y of the outer shield 101. The latching tabs 132, 134 can facilitate the insertion of the inner shield 30 into the inner cavity 108 of the outer shield 101. In one example, the circumferential width of one latching tab 134 is greater than the circumferential width of the other latching tab 132.

[0053] refer to Figure 7 , shows an inner shield 30 that can be used in the present invention. The inner shield 30 extends along a longitudinal axis Z. When the inner shield 30 is at least partially enclosed in the outer shield 101, the axis Z coincides with the axis Y. The inner shield 30 preferably has a cylindrical shape and a circular cross-section. Advantageously, the inner shield 30 includes an inner proximal connecting portion 140, which is configured to sealingly engage the end 35 of the injection device 10, such as Figure 1 As shown. The inner proximal connection portion 140 preferably has a larger diameter than the rest of the inner shield 30. The inner proximal connection portion 140 can be formed as a circumferential flange. The inner proximal connection portion 140 is therefore more easily distinguishable from the rest of the body, and the fixation of the inner shield 30 to the outer shield 101 is improved, as described below.

[0054] The inner shield 30 is preferably made of a material having elastomeric properties. In this way, when the inner shield 30 is connected to the injection device 10, the inner proximal connection part 140 can be slightly deformed to match the shape of the end 35. At the same time, the needle end or the distal part of the needle 14 can penetrate the inner shield 30. This further reduces the risk of the medical composition leaking through the needle 14 to the external environment. The material having elastomeric properties is preferably a thermoplastic elastomer, an elastomer or a rubber. Preferably, the material having elastomeric properties is sterilizable.

[0055] In one embodiment, the outer shield 101 at least partially surrounds the inner shield 30. The outer needle shield 101 is fixed to the inner needle shield 30. To this end, the inner proximal connection portion 140 of the inner shield 30 is partially inserted into the two undercuts 120, 122 in a snap-fit ​​connection. The inner proximal connection portion 140 of the inner shield 30 abuts both the proximal surfaces 124, 128 and the distal surfaces 126, 130 of the two undercuts 120, 122, thereby preventing any translational movement of the inner shield 30 relative to the outer shield 101 along the axis Y. Advantageously, the inner proximal connection portion 140 also abuts the side surfaces of the undercuts 120, 122, thereby preventing any rotational movement of the inner shield 30 relative to the outer needle shield 101 around the axis Y.

[0056] The inner shield 30 and the outer shield 101 may be fixed together by other fixing means in addition to or in addition to the snap-fit ​​connection of the undercuts 120, 122 and the inner proximal connecting portion 140. When the needle cap 100 is mounted on the injection device 10, the inner shield 30 encloses at least a portion of the terminal end 35 of the barrel 18, and the proximal connecting portion 140 firmly contacts the proximal portion of the terminal end 35. The needle cap 100 is thus tightly and sealingly connected to the terminal end 35.

[0057] In order to install the needle cap 100 on the syringe, the outer shield 101 is first placed on the inner shield 30, and then the entire needle cap 100 is installed on the syringe. As previously described, when the inner shield 30 and the outer shield 101 are fixed together, the proximal connection portion 140 of the inner shield 30 will be locked into the undercuts 120, 122 defined in the collar 110 of the outer shield 101. Once locked into the undercuts 120, 122, the proximal connection portion 140 is prevented from moving in the distal direction due to the distal surfaces 126, 130 of the undercuts 120, 122, and the proximal connection portion is prevented from moving in the proximal direction due to the proximal surfaces 124, 128 of the undercuts 120, 122.

[0058] After the needle cap 100 has been positioned on the medical injection device 10, the needle cap 100 can be moved in the distal direction to remove it from the medical injection device 10. When the user applies a pulling force to the outer shield 101, the outer shield 101 moves in the distal direction together with the inner shield 30. As the outer shield 101 moves in the distal direction, the proximal surface 124 of the first undercut 120 will begin to contact and abut with the proximal connecting portion 140 of the inner shield 30. Once the proximal surface 124 of the undercut 120 contacts the proximal connecting portion 140, the proximal surface 124 begins to push the proximal connecting portion 140 in the distal direction. As the proximal connecting portion 140 is pushed in the distal direction, the proximal connecting portion 140 begins to bend, causing the collar 142 of the inner shield 30 to be pulled away from the medical injection device 10 in the radial direction.

[0059] As the proximal connecting portion 140 is pulled away in the radial direction due to contact with the proximal surface 124 of the first undercut 120, the opposite side of the proximal connecting portion 140 bends toward the proximal surface 128 of the second undercut 122. Due to the engagement between the opposite side of the proximal connecting portion 140 and the proximal surface 128, the second undercut 122 begins to help pull the inner shield 30 away from the syringe tip 35 of the medical injection device 10. Once the outer shield 101 has been pulled a sufficient distance, the inner shield 30 is pulled away from the syringe tip 35 of the medical injection device 10.

[0060] All components of the medical injector 10 may be constructed from any known material, and are desirably constructed from medical grade polymers.

[0061] Although the present disclosure has been described as having an exemplary design, the present disclosure can be further modified within the spirit and scope of the present disclosure. Therefore, the present application is intended to cover any variation, use or adaptation of the present disclosure using its general principles. In addition, the present application is intended to cover deviations from the present disclosure within the known or customary practices in the field to which the present disclosure belongs and within the limits of the appended claims.

[0062] The present application will be further described below by way of non-limiting examples.

[0063] Example measurement of pull-out force

[0064] Measurement of pull-out force.

[0065] This article compares needle caps including either the inner and outer shields of the prior art (where the outer shields do not include any undercuts) or the outer shields of the present invention, both pre-installed onto the ends of glass syringes. The glass syringes are identical for both the needle caps of the prior art and the needle caps of the present invention.

[0066] In these tests, five outer shields of the prior art and five outer shields of the invention provided with two undercuts as described in the invention were provided.

[0067] The force required to remove the needle cap from the syringe is measured. The test is performed on a traction table (500 mm / min). The method comprises the following steps: placing the syringe on a stand, gripping the needle cap with pneumatic jaws, and pulling the needle cap at a constant displacement rate to remove it. The force required to pull the needle cap to remove it from the tip is recorded. The results are shown in the table below.

[0068]

[0069] The force recorded is the maximum value of the force required to remove the needle cap recorded as a function of time. The force is the pull-out force, designated as the "POF value". As shown in Table 1, the average POF recorded for the needle cap of the prior art is 17.48 N and the average POF recorded for the needle cap of the present invention is 12.49. These values ​​of the pull-out force clearly show that the needle cap of the present invention results in a significant reduction in the pull-out force compared to the known needle cap. The pull-out force is reduced by about 29%.

Claims

1. A needle cap (100) for protecting a needle (14) mounted on a tip (35) of a barrel (18) of a medical injection device (10), wherein the tip (35) extends from a distal end (34) of the barrel (18), the needle cap (100) comprising: an inner shroud (30) extending along a longitudinal axis (Z), the inner shroud including the distal end (35) configured to sealingly contact the barrel (18), and An outer shield (101), the outer shield at least partially surrounding the inner shield (30) and being fixed to the inner shield (30), the outer shield (101) comprising: a body (102) comprising a first open end (104), a second end (106), and a sidewall extending between the first open end (104) and the second end (106), the body defining a cavity (108) for receiving the inner shroud (30) therein, a first undercut (120) defined adjacent the first open end (104) of the body (102), and a second undercut (122) defined adjacent the first open end (104) of the body (102); Features: A distance from the first open end (104) to a proximal edge (24) of the first undercut (120) is greater than a distance from the first open end (104) to a proximal edge (128) of the second undercut (122); The inner shield (30) includes a proximal connecting portion (140) received in the first undercut (120) and the second undercut (122), During removal of the needle cap (100) from the medical injection device (10), as the outer shield (101) moves in the distal direction under tension, the proximal surface (124) of the first undercut (120) first contacts the proximal connecting portion (140), while the opposite side of the proximal connecting portion (140) bends toward the proximal surface (128) of the second undercut (122), and Engagement between the proximal connection portion (140) and the proximal surface (128) of the second undercut (122) assists in disengaging the inner shield from the tip (35).

2. The needle cap according to claim 1, wherein a longitudinal length of the first undercut (120) extending from the first open end (104) toward the second end (106) is smaller than a longitudinal length of the second undercut (122) extending from the first open end (104) toward the second end (106).

3. The needle cap according to claim 1 or 2, further comprising: a first locking tab (132) extending from an inner surface of the body (102) proximate the first undercut (120); and A second locking tab (134) extends from an inner surface of the body (102) proximate the second undercut (122).

4. The needle cap according to claim 3, wherein a circumferential width of the first locking piece (132) is greater than a circumferential width of the second locking piece (134).

5. The needle cap according to claim 3 or 4, wherein the first locking tab (132) and the second locking tab (134) comprise proximal inclined surfaces (136).

6. The needle cap according to any one of claims 1 to 5, wherein the difference between the distance from the first open end (104) to the proximal edge (124) of the first undercut (120) and the distance from the first open end (104) to the proximal edge (128) of the second undercut (122) is at least 1 mm.

7. The needle cap according to any one of claims 1 to 6, wherein the first undercut (120) and the second undercut (122) are diametrically opposite to each other.

8. The needle cap according to any one of claims 1 to 7, wherein the first undercut (120) and the second undercut (122) are rectangular in shape.

9. The needle cap according to any one of claims 1 to 8, wherein the body (102) defines at least one U-shaped groove (116) on an outer surface thereof.

10. The needle cap according to claim 9, wherein the U-shaped groove (116) comprises a distal wall (118) and a proximal wall (119) extending radially from the body (102).

11. The needle cap according to any one of claims 1 to 10, wherein a distance from the first open end (104) to a distal edge (126) of the first undercut (120) is equal to a distance from the first open end (104) to a distal edge (130) of the second undercut (122).

12. The needle cap according to any one of claims 1 to 11, wherein the outer shield (101) is fixed to the inner shield (30) by a snap-fit ​​connection, the inner proximal connecting element (140) of the inner shield being inserted into the first and second undercuts of the outer shield to form the snap-fit ​​connection.

13. A medical component comprising: A medical injection device (10), comprising: a cartridge (18) defining a reservoir (20) adapted to contain a medicinal composition; a tip (35) extending from a distal end face (34) of the barrel (18), the tip defining a fluid path extending through the tip (35) and in fluid communication with the reservoir, a needle (14) in communication with the reservoir (20); and The needle cap (100) according to any one of claims 1 to 12, wherein the needle cap is suitable for covering the needle (14).

14. The medical assembly according to claim 13, wherein the barrel (18) and the tip (35) of the medical injection device (10) are made of glass.

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