WO2024227740A1

WO2024227740A1 - Medicament delivery device

Info

Publication number: WO2024227740A1
Application number: PCT/EP2024/061781
Authority: WO
Inventors: Anders Holmqvist
Original assignee: Norrneo AB
Current assignee: Norrneo AB
Priority date: 2023-05-03
Filing date: 2024-04-29
Publication date: 2024-11-07
Anticipated expiration: 2025-11-03
Also published as: SE2350530A1

Abstract

The present invention relates to a medicament delivery device comprising a body (12), a needle cover (38) movable in relation to the body (12), a container (74) provided with an injection needle (76) and containing medicament to be injected through the needle (76), a power pack (85) provided in the body (12) and operatively arranged to act on the container for expelling medicament, the power pack (85) comprising a plunger rod (124) and force element (122) acting on the plunger rod (124), a holding element (130) comprising at least two ledges (138) that fit into corresponding ledges (129) on the plunger rod (124) for holding the plunger rod (124) in a tensioned state, the holding element (130) further comprising release elements (152) arranged to interact with the needle cover (38) such that when the needle cover (38) is moved into the body (12) when the device is pressed against an injection site during penetration, the needle cover (38) interacts with the release elements (152), causing the ledges (138) of the holding element (130) to move out of contact with the ledges (129) of the plunger rod (124), wherein an injection is performed.

Description

MEDICAMENT DELIVERY DEVICE

TECHNICAL AREA

The present invention relates to a medicament delivery device and in particular an auto-injector.

BACKGROUND OF INVENTION

Medicament delivery devices have been on the market for many years for selfadministration of drugs. Many of these are designed as auto-injectors with the aim that the end-user should be required to perform as few steps as possible in order to initiate an injection.

US 3,797,489 discloses an auto-injector with a pre-tensioned power spring operably connected to a plunger rod. In order to activate the device a safety cap with a safety pin is removed and the device is pressed against an injection site, which causes a syringe with a needle to move forward and performing a penetration. A release of the plunger rod will then cause an injection. A retraction spring will be tensioned, such that when the device is removed after injection, the syringe and the needle are moved back into the injector.

US 5,681 ,291 discloses an auto-injector having a needle shield movable inside a housing of the device. When the injector is pressed against an injection site, the needle shield is moved rearwards, causing a manual penetration. The movement of the needle shield will further cause an activation of a power spring acting on a plunger rod for performing an injection. When the device is removed from the injection site, a spring pushes the needle shield into a position shielding the needle, in which position it is locked.

Even though many of these devices on the market have adequate functionality and robustness, there is always room for improvements.

BRIEF DESCRIPTION OF INVENTION

The aim of the present invention is to provide a medicament delivery device with a high degree of robustness and reliable functionality and safety features. This aim is obtained with a medicament delivery device according to the independent patent claim. Preferable embodiments of the invention form the subject of the dependent patent claims.

According to a main aspect, a medicament delivery device is provided, comprising a body, a needle cover movable in relation to the body, a container provided with an injection needle and containing medicament to be injected through the needle, a power pack provided in the body and operatively arranged to act on the container for expelling medicament, the power pack comprising a plunger rod and force element acting on the plunger rod, a holding element comprising at least two ledges that fit into corresponding ledges on the plunger rod for holding the plunger rod in a tensioned state, the holding element further comprising release elements arranged to interact with the needle cover such that when the needle cover is moved into the body when the device is pressed against an injection site during penetration, the needle cover interacts with the release elements, causing the ledges of the holding element to move out of contact with the ledges of the plunger rod, wherein an injection is performed.

With this solution, the plunger rod may be held in a tensioned state by the holding element, without any additional features or components needed for holding it in this state until activation.

According to another aspect, the contact surfaces between the ledges of the holding element and the ledges of the plunger rod are generally planar. The generally planar surfaces provide the holding of the plunger rod in the tensioned state, thus the components do not slide in relation to each other before activation.

Moreover, the at least two ledges of the holding element are connected to radially flexible members of the holding element. Further, the ledges of the holding element are caused to move outwards in relation to the plunger rod. Moreover, the ledges of the plunger rod may be formed by an annular recess or and wherein the at least two ledges of the holding element have generally complemental surfaces to the recess. In order to have a protection against unintentional activation, possible due to the device being dropped on a hard surface, the power pack further comprises a locking element for preventing movement of the at least two ledges of the holding element before interaction with the needle cover. In this regard, movement of the needle cover causes the locking element to be moved out of engagement with the holding element.

These and other aspects of, and advantages with, the present invention will become apparent from the following detailed description of the invention and from the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

In the following detailed description of the invention, reference will be made to the accompanying drawings, of which

Fig. 1 is a perspective view of an embodiment of a medicament delivery device according to the invention,

Figs. 2-3 are cross-sectional views of the device of Fig. 1 ,

Figs. 4-17 are detailed views of components comprised in the device of Fig. 1 , and

Figs. 18-25 are functional views of the device of Fig. 1 .

DETAILED DESCRIPTION OF THE INVENTION

In the detailed description, the word longitudinal will be used, defining directions coinciding with an axis L as shown in Fig. 1 . The word transversal or radial will be used, defining directions generally perpendicular to the axis L. Further the word proximal will be used, P in Fig. 1 , defining the part or end or direction of/or the device that is pressed against a dose delivery site of a patient or user. The word distal will also be used, D in Fig. 1 , defining the part or end or direction of/or the device that is opposite to proximal. The embodiment of a medical delivery device 10 shown in the drawings comprises a generally elongated, tubular body 12, Figs 1 , 4 and 5. The body 12 shown has a generally elliptic cross-sectional shape with two generally flat planar oppositely positioned side surfaces 14. At one end of the body, hereafter named the proximal end, the body is provided with a section 16 with a generally circular cross-section, whereby a proximally directed surface 18 is formed. Along the side surfaces, two proximally directed portions 20 are provided.

A generally tubular end cap 22 is further provided for the medical delivery device, Figs, land 6, having a generally corresponding shape as the body 12. The distal edge 24 of the end cap 22 has a shape as to fit onto the proximal end of the body 12 wherein the edge is in contact with the proximally directed surface 18 and the portions 20 of the body. In order to provide a holding resistance of the end cap 22 when mounted on the body 12, the inner surface of the end cap 22 is provided with protrusions 26 that fit into recesses 28 on the outer surface of the proximal end section of the body 12. The proximal end of the end cap 22 is further provided with an end wall 29 having a central passage that is closed with an end lid 30, preferably snap-fitted to the end cap. The end cap 22 is further provided with a generally tubular needle shield remover 32, such as a rigid needle shield, RNS, extending distally from the proximal end of the end cap 22, Fig. 6. The distal end of the needle shield remover 32 is provided with an inwardly extending circumferential ledge 34 and two oppositely arranged slits 36 extending in a longitudinal direction of the device, thereby providing a radially flexing action of the needle shield remover 32.

The device 10 is further provided with a generally tubular needle cover 38, Fig. 7. The proximal end of the needle cover 38 is provided with an end wall 40 having a central opening 42 through which the needle shield remover 32 of the end cap 22 protrudes when assembled. The needle cover 38 is provided with two distally directed arms 44, integrated on the outside thereof. The arms 44 are arranged to fit into two elongated grooves 46 on the inner surface of the side surfaces 14 of the body 12, Fig. 4, providing a guide against turning, rotation or pull out of the needle cover 38 along a longitudinal axis of the device 10 in the proximal direction. The distal ends of the arms 44 are arranged with a first narrow straight section 48 having somewhat pointed ends. The first section 48 transforms in a second section 50 with inclined side surfaces. The second section 50 then transforms in a third straight section 52 that is wider than the first section 48. On the inner surfaces of the arms, two inwardly directed circular protrusions 54 are provided. Further, the needle cover 38 is provided with two cut-outs 56 extending in the longitudinal direction.

The needle cover 38 is arranged outside a generally tubular syringe holder 58, Fig. 8. The syringe holder 58 is provided with elongated openings 60 surrounded by ledges 62 that, when the syringe holder 58 is arranged in the body 12 abut the inner surface of the body 12 wherein the elongated openings 60 are aligned with corresponding elongated openings 64 on the body, Fig. 5. The syringe holder 58 is fixated to the body 12 by two radially extending ledges 66 that fit into cut-outs 68 in the body 12. When the syringe holder 58 is fitted to the body 12, the ledges 62 of the openings 60 of the syringe holder 58 fit in the cut-outs 56 of the needle cover 38, allowing movement and guiding of the needle cover 38 as will be explained. The syringe holder 58 is further arranged with an outwardly directed circumferential ledge 70. The proximally directed surface of the ledge 70 is provided with a seat in which a distal end of a helical needle cover spring 72 fits. The proximal end of the needle cover spring 72 will be in contact with an inner surface of the end wall 40 of the needle cover.

Inside the syringe holder 58 a syringe 74 can be fitted, Figs 2 and 3. The syringe 74 is provided with an injection needle 76 at its proximal end. The needle 76 is protected and kept sterile by a needle shield 78. The syringe 74 is filled with medicament and contained there by a resilient stopper 80. The distal end of the syringe 74 is provided with a flange 82 that when fitted into the syringe holder 58 rests on a distal end surface of the syringe holder 58.

Distally of the syringe holder 58 a generally tubular spring house 84 is provided, Figs. 9 and 10, that is part of a power pack 85, Fig. 2. At the proximal end of the spring house 84 two oppositely positioned arms 86 are arranged with the free ends in the proximal direction and provided with outwardly directed ledges 88, which ledges 88 have a wedge-shape. The arms 86 are flexible in the radial direction. At about a mid-position along the spring house 84, two oppositely positioned, partially circumferential, ledges are provided 89. Each ledge 89 is arranged with a wedge- shaped recess 90 on proximally directed surfaces thereof. The distal part of the spring house is provided with a section 92 with a somewhat smaller diameter. Two transversal slits 94 are further provided between the larger and smaller diameter sections of the spring house 84. The slits 94 are separated by longitudinal ridges 96 extending in the distal direction, having the same measure in the transversal direction as the larger section of the spring house 84. The ridges 96 extend along the smaller section 92 to the distal end of the spring house 84. Ridges 99 also extend on the inner surface, positioned inside the ridges 96. Adjacent the distal end of the spring house 84, two oppositely positioned generally rectangular openings 98 are provided. On the inner surface of the spring house 84, an annular ledge 100 is provided, adjacent and proximal of the slits 94. A distal end of a compression spring 122, hereafter named power spring, rests against the annular ledge 100.

A generally tubular locking element 102, hereafter named rotator lock, Figs. 11 and 12, is provided outside the spring house 84. Axial movement of the rotator lock 102 in the proximal direction is prevented by the flexible arms 88 and the ledge 88 at the proximal end of the spring house 84. Further, axial movement in the distal direction is also prevented by the ledges 89. The rotator lock 102 is provided with two first ledges 104 on its outer surface, positioned on opposite sides. The ledges 104 comprise a first section 104¹ extending in the longitudinal direction from the proximal end and a second section 104" connected to or being integral with the first section 104¹ and extending at an angle in relation to the longitudinal direction. The distal end of the second section 104" may be somewhat rounded towards the longitudinal direction at the distal end of the rotator lock 102. Further, two second ledges 106 are arranged on the outer surface that are parallel with the first sections 104¹ of the first ledges 104 and with about the same extension in the longitudinal direction. Two third ledges 108 are also provided on the outer side of the rotator lock 102, positioned a distance from the second ledges 106 along the circumference and with an extension parallel with the longitudinal direction along the length of the rotator lock 102. Between the second and the third ledges106, 108, a flexible arm 110 is provided, with the free end of the arm directed proximally. The end of the flexible arm 110 is provided with a wedge-shaped ledge 112. The distal end surface of the rotator lock 102 is provided with two distally directed rectangular protrusions 114, provided with side surfaces 115. Further, cut-outs 116 are made in the distal area forming two flexible arms 118 extending around the circumference. The ends of the flexible arms 118 are provided with wedge-shaped protrusions 120. In an initial position of the rotator lock in relation to the spring house, the side surfaces are in contact with the ends of the ledges 89. The rotator lock 102 is releasably held in this position by the arms 118 with the wedge-shaped protrusions 120 fitting into the wedge-shaped recesses 90 of the ledges 89 of the spring house 84.

Inside the spring house 84, the power spring 122, Figs. 2 and 3, is provided. Further, inside the power spring 122, an elongated plunger rod 124 is provided, Figs 2, 3 and 13, wherein the drives spring 122 and the plunger rod a parts of the power pack 85. The proximal end of the plunger rod 124 is arranged with a ledge 126 on which the proximal end of the power spring 122 rests. The distal end of the plunger rod 124 is provided with an annular groove 128. The distal side surface 129 of the annular recess is generally flat and generally perpendicular to the longitudinal direction and provides a seat for holding the plunger rod 124 with the power spring 122 tensioned, as will be described.

Also surrounding the spring house 84 at a distal area thereof is a generally tubular holding and release element 130, Figs. 14 and 15, hereafter named releaser, that also forms a part of the power pack 85. The releaser 130 is provided with two pairs of longitudinally extending first slits 132 on opposite sides. A transversally extending second slit 134 is further provided between each of one of the pairs of first slits 132, wherein a flexible stem 136 is formed between the pair of first slits 132. A transversal wall 138, forming a holding element, inside the releaser 130 is provided at the distal side of the transversal first slits 132. A transversal third slit 140 is arranged in the transversal wall 138. At the centre of the third slit 140 of the transversal wall 138, inwardly directed protrusions 142 are arranged, having inner wall sections 144 forming circle sectors. The distal end area of the releaser 130 is also provided with two longitudinally extending fourth slits 146 that extend from the transversal slit 140 to the distal end of the releaser 130. The distal area of the releaser 130 is further provided with longitudinally extending fifth slits 147 on each side of the fourth slit 146, thus forming two pairs of distally directed arms 148. At the free end of the arms 148, protrusions 150 are provided, directed towards each other in each pair. Further, two pairs of generally rectangular protrusions 152 extend outwards from the transversal wall 138 on each side of the transversal third slit 140.

A locking element 154 is further provided, Fig. 16, hereafter named locker, that also forms a part of the power pack 85. The locker 154 is in the form of a ring 155 having an inner diameter somewhat larger than the diameter of the outer surface of the releaser 130. The locker 154 is arranged around the releaser 130 distally of the rectangular protrusions 152 in an initial position. The locker 154 is provided with two oppositely arranged and generally rectangular protrusions 156 extending inwards. When in the initial position, the rectangular protrusions 156 are positioned between each of the pairs of the arms 148. Further, two outwardly directed, generally rectangular, protrusions 158 are provided outside the inwardly extending protrusions 156.

The device is further provided with an end hat 160 at the distal end of the body, Fig. 17. The end hat 160 has an end cover 162 that when in position abuts the distal surface of the body. On the proximally directed surface of the end cover 162, a tubular section 164 is arranged. The tubular section 164 is provided with two oppositely arranged cut-outs 166. Each side of the cut-outs 166 is provided with an outwardly directed ledge 168. Each ledge 168 is further provided with an outwardly directed protrusion 170 at their proximal ends. The protrusions 170 are provided with a chamfered portion. When the end hat 160 is attached to the body 12, the protrusions 170 fit into recesses 172 at the distal area of the body 12. The end hat 160 is further provided with a central tubular element 174. On the outer side surface of the tubular element 174, two longitudinally extending recesses 176 are provided on opposite sides. Each recess 176 is provided with a transversal ledge 178, wherein the proximally directed side surface of each transversal ledge 178 is chamfered. When the device is assembled, the transversal ledges 178 fit into the rectangular openings 98 of the spring house 84, whereby the spring house 84 is fixed axially and rotationally to the end hat 160 and thus to the body 12. The inner ridges 99 of the spring housing also fit into the recesses 176 to provide a rotational lock between the end hat 160 and the spring house 84.

The device is intended to function as follows. When the device is delivered to a user, the end cap 22 is attached to the proximal end of the body 12 and the needle shield remover 32 surrounds the needle shield 78 with the ledges of the needle shield remover behind the distal end of the needle shield as seen in Fig. 2. The protrusions 54 of the needle cover are positioned between the first sections 104¹ and the second ledges 106 as seen in Fig. 18. Further, the power spring 122 is in a tensioned state and the plunger rod 124 is held in this tensioned state by the transversal wall 138 and its protrusions 142 positioned in the annular groove 128 of the plunger rod 124, Figs. 20 and 21 . The distance d as seen in Fig. 15 is chosen smaller than the diameter of the plunger rod 124, wherein the transversal wall 138 is positioned in the annular groove 128. Because of this and the planar surface 129 of the groove 128 and the planar surface of the transversal wall 138, the plunger rod 124 is held by the releaser 130 in a relatively firm and safe way. In order to ascertain that the plunger rod 124 cannot be released from the releaser 130 prematurely due to for instance if the device is dropped on a floor surface, the ring 155 of the locker 154 is positioned around the distal end of the releaser 130, thereby preventing any movement of the transversal wall 138 in the radial direction. In order to further prevent that the locker 154 leaves this position prematurely due again to a drop of the device, the inwardly directed protrusions 156 of the locker 154 are positioned between the pair of arms 148 of the releaser 130, which arms 148 cause a holding force on the protrusions as seen in Fig. 21. This holding force and/or holding action may be increased if the surfaces of the protrusions in contact with the arms are provided with recesses that the protrusions of the arms fit into.

When the device is to be used, the end cap 22 is removed by pulling it off from the body 12. The ledges 34 of the needle shield remover 32 of the end cap 22 are positioned distally of the needle shield 78 when the device is assembled, and the pulling off of the end cap 22 will then also remove the needle shield.

A user then presses the proximal end of the device, i.e. the needle cover 38 that is protruding out of the body 12 as seen in Fig. 1 , against a dose delivery site. This causes the needle cover 38 to move into the body 12 of the device, wherein a penetration of the needle is performed on the dose delivery site. The distal end of the syringe 74 is supported by the proximal end of the spring house in order to make the syringe stay in place during penetration. The movement of the needle cover 38 in turn causes the protrusions 54 of the needle cover 38 to move along the first ledge 104 of the rotator lock 102, and when moving along the inclined section 10411 of the first ledge 104, the rotator lock 102 will rotate around the spring house 84 until the protrusions are in the distal area of the rotator lock 102 between the first ledge 104 and the third ledge 108, Fig. 19. In this position, the wedge-shaped protrusions 120 of the arms 118 of the rotator lock 102 have passed the ledges 89 of the spring house 84, thereby preventing the rotator lock 102 from rotating in the opposite direction, Fig. 19a.

The movement of the needle cover 38 will also cause the distal ends of the arms 44 to be moved in contact with the outwardly directed protrusions 158 of the locker 154, Fig. 19, and further movement will cause the inwardly directed protrusions 156 of the locker 154 to be moved out of contact with the arms 148 of the releaser 130, Fig. 22. In this position, the plunger rod 124 is still held firmly by the releaser 130, wherein the narrow sections 48 of the arms 44 of the needle cover 38 are positioned between the outwardly directed rectangular protrusions 152 of the releaser 130.

Further movement of the needle cover 38 will cause the inclined sections 50 of the arms 44 of the needle cover 38 to push on the rectangular protrusions 152 of the releaser 130, Fig. 23 , whereby the transversal wall 138 will be moved radially outwards due to the flexing action of the stems 136 until the transversal wall 138 and the protrusions 142 are moved out of contact with the annular groove 128 of the plunger rod, see Fig. 24. The plunger rod 124 is now released and due to the force of the power spring 122, the plunger rod 124 is moved proximally and acting on the stopper 80 of the syringe 74, whereby an injection is performed in that the stopper 80 is moved proximally in the syringe 74 and expels medicament through the injection needle 76. The progress of the injection can be viewed in the openings 64 of the body. When the injection is completed, the device is removed from the injection site. The needle cover 38 is free to move and will be pushed in the proximal direction by the needle cover spring 72. The proximal movement of the needle cover 38 will cause its protrusions 54 to slide over and pass the wedge-shaped ledges 112 of the arms 110 of the rotator lock 102, thereby locking the needle cover 38 in an extended position covering the needle 76, Fig. 25. The device can now be discarded.

Even though the plunger rod 124 has been shown with ledges 129 that are formed by an annular groove 128, it is to be understood that the ledges may be parts of outwardly directed protrusions on the plunger rod, cut-out recesses or undercuts on the side of the plunger rod, and that the transversal wall of the releaser is formed in a complementary way to provide holding elements.

It is to be understood that the embodiment described above and shown in the drawings is to be regarded only as a non-limiting example of the invention and that it may be modified in many ways within the scope of the patent claims.

Claims

PATENT CLAIMS

1 . Medicament delivery device comprising a body (12), a needle cover (38) movable in relation to the body (12), a container (74) provided with an injection needle (76) and containing medicament to be injected through the needle (76), a power pack (85) provided in the body (12) and operatively arranged to act on the container for expelling medicament, the power pack (85) comprising a plunger rod (124) and force element (122) acting on the plunger rod (124), a holding element (130) comprising at least two ledges (138) that fit into corresponding ledges (129) on the plunger rod (124) for holding the plunger rod (124) in a tensioned state, the holding element (130) further comprising release elements (152) arranged to interact with the needle cover (38) such that when the needle cover (38) is moved into the body (12) when the device is pressed against an injection site during penetration, the needle cover (38) interacts with the release elements (152), causing the ledges (138) of the holding element (130) to move out of contact with the ledges (129) of the plunger rod (124), wherein an injection is performed.

2. Medicament delivery device according to claim 1 , wherein the contact surfaces between the ledges (138) of the holding element (130) and the ledges (129) of the plunger rod (124) are generally planar.

3. Medicament delivery device according to claims 1 or 2, wherein the ledges (138) of the holding element (130) are caused to move outwards in relation to the plunger rod (124).

4. Medicament delivery device according to any of the preceding claims, wherein the at least two ledges (138) of the holding element (130) are connected to flexible members (136) of the holding element (130).

5. Medicament delivery device to any of the preceding claims, wherein the ledges (129) of the plunger rod (124) are formed by an annular recess (128) and wherein the at least two ledges (138) of the holding element have generally complemental surfaces (144) to the recess (128).

6. Medicament delivery device according to any of the preceding claims, wherein the power pack (85) further comprises a locking element (154) for preventing movement of the at least two ledges (138) of the holding element (130) before interaction with the needle cover (38).

7. Medicament delivery device according to claim 5, wherein movement of the needle cover (38) causes the locking element (154) to be moved out of engagement with the holding element (130).