Syringe cartridge

Abstract

An apparatus for use with a medicament container comprising: a main body; a shroud at least partially received within the main body, wherein the shroud comprises a shroud portion and a drive portion; the shroud portion being movable with respect to the main body between a retracted position and an extended position; a biasing member arranged within the main body and configured to bias the shroud from the retracted position to the extended position; a plunger arm movable between: an extended state in which the plunger arm inhibits rotation of the drive portion; and a depressed state in which the plunger arm allows rotation of the drive portion and movement of the shroud portion to the extended position.

Description

[0001] M&C PX221301GB

[0002] 1

[0003] SYRINGE CARTRIDGE

[0004] FIELD OF THE INVENTION

[0005] The present disclosure relates to medicament container delivery devices, syringes, devices for use with syringes, and in particular safety syringes.

[0006] BACKGROUND

[0007] Safety syringes are syringes with built-in safety mechanisms designed to reduce the occurrence of needlestick injuries. The safety mechanism may automatically retract the syringe within the housing after use.

[0008] SUMMARY

[0009] According to a first aspect of the invention, there is provided an apparatus for use with a medicament container comprising: a main body; a shroud at least partially received within the main body, wherein the shroud comprises a shroud portion and a drive portion; the shroud portion being movable with respect to the main body between a retracted position and an extended position; a biasing member arranged within the main body and configured to bias the shroud from the retracted position to the extended position; a plunger arm movable between: an extended state in which the plunger arm inhibits rotation of the drive portion; and a depressed state in which the plunger arm allows rotation of the drive portion and movement of the shroud portion to the extended position.

[0010] The shroud portion may be integrally formed with the drive portion to provide said shroud.

[0011] The drive portion may have at least one projection extending radially outwards. The projection may comprise an angled surface. The body may comprise a surface projecting radially inwards, wherein said projection abuts the surface for at least part of said movement of the shroud portion to the extended position.

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[0014] The projection may comprise a surface with an angle between 10 and 35 degrees with respect to a main longitudinal axis of the apparatus, and said surface may have a corresponding angle between 10 and 35 degrees.

[0015] The abutting may be arranged to impart rotational movement of the drive portion relative to the main body when driven by said biasing member.

[0016] The plunger arm may comprise a syringe plunger and at least one prong and said at least one prong may define a window. The prong may comprise a U-shaped profile in radial direction, wherein the U-shaped profile arranged to receive the projection. The U-shape may comprise three adjacent straight sides.

[0017] The plunger arm may comprise two prongs, wherein each prong defines a window, and wherein the windows are radially opposite to each other.

[0018] The main body comprises at least one guide channel for receiving said at least one prong.

[0019] The apparatus may further comprise a syringe holder telescopically arranged within the main body. The syringe holder may comprise a first portion and a second portion, wherein the first portion has a smaller outer diameter than the second portion. The syringe holder may comprise at least one shoulder. The at least one shoulder may define an opening for receiving the at least one prong. The main body may comprise at least one ledge, and the at least one ledge may abut the shoulder.

[0020] The syringe holder may be telescopically arranged within the drive portion.

[0021] The biasing member may be arranged in the interior of the drive portion. The biasing member may be arranged around said first portion of the syringe holder and may further be compressed between an end portion of the shroud and said second portion of the syringe holder.

[0022] According to a second aspect of the invention, an assembly is provided which comprises the apparatus according to the first aspect, a syringe, a needle shield, and a cap.

[0023] 38322478-1M&C PX221301GB

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[0025] The needle shield may be mechanically coupled to the syringe and the cap may be mechanically coupled to the needle shield.

[0026] The cap may be mechanically coupled to the needle shield by at least one snap fit.

[0027] According to third aspect, a method of assembling the apparatus the first aspect is provided, the method comprising: inserting the shroud in the main body; inserting a spring into the shroud; inserting the syringe holder into the shroud, thereby biasing the spring; inserting the plunger arm into the main body.

[0028] The method may further comprise inserting the syringe into a syringe holder. Inserting the shroud into the main body may comprise aligning the projection of the shroud and the surface of the main body.

[0029] BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Some embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which:

[0031] Figure 1 depicts an exploded view of the apparatus, according to an embodiment. Figure 2 shows a perspective view of the plunger arm of Figure 1 , according to an embodiment.

[0032] Figure 3 shows a perspective view of the syringe holder of Figure 1, according to an embodiment.

[0033] Figure 4 shows a perspective view of the shroud of Figure 1, according to an embodiment.

[0034] Figure 5 shows a side view of the main body of Figure 1 , according to an embodiment. Figure 6 shows a perspective view of the main body shown in Figure 5, according to an embodiment.

[0035] Figure 7 shows a cross section of the apparatus, according to an embodiment.

[0036] Figure 8 depicts a flow diagram of a method of assembling the apparatus, according to an embodiment.

[0037] 38322478-1M&C PX221301GB

[0038] 4

[0039] Figure 9 shows a perspective view of the apparatus with the shroud of Figure 4 in an extended position and the plunger arm of Figure 2 in a depressed state, according to an embodiment.

[0040] Figure 10 depicts a side view cross section of Figure 9, according to an embodiment.

[0041] DETAILED DESCRIPTION

[0042] Throughout the specification, the term “proximal” refers to the patient facing end of the safety syringe. In other words, the proximal end of the safety syringe is the end closest to the injection site during use. Similarly, the term “distal” refers to the non-patient end of the safety syringe or component thereof. In other words, the term “distal” means distant or remote from the injection site during use.

[0043] Other relative terms such as axial, longitudinal and the like are used to aid description of the device. The device comprises in very general terms at least partially a cylindrical or tubular shape and the longitudinal axis refer to the main longitudinal axis of the cylinder, while the radial direction refers to the radial direction in such cylindrical coordinate system. However, the cross section of the device in radial direction does not need to be circular, even though a syringe received within the device typically does have a circular cross section.

[0044] In general terms, there is provided an apparatus for use with a syringe. Although the primary use of the apparatus is with a syringe, a needleless medicament container may also be used to deliver a medicament to a user. Medicament can be delivered to a site below the skin through the use of a jet of high speed fluid without using a needle. The shroud would not cover a needle in that case, but would cover the end of the container to avoid contamination after use.

[0045] As an alternative to a syringe, the medicament may be contained within a cartridge. Cartridges do not comprise a needle integrally fixed thereto. Typically, cartridges comprise a septum, which seals an open forward end of the cartridge to retain the medicament within the cartridge. The septum may be secured to the cartridge by a crimp and may typically be made of an elastomeric / deformable material. The cartridge may be configured for attachment to a needle assembly. The septum is piercable, or otherwise breakable / releasable, to allow the medicament to be dispensed from the cartridge and

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[0048] into the patient, via the needle assembly. Such needle assemblies may comprise needles comprising a forward tip for insertion into the patient, and a rearward tip, which is configured to pierce the septum to allow the medicament to be dispensed from the cartridge.

[0049] An exploded view of the apparatus is shown in Figure 1. The syringe can be manufactured and provided separately from the apparatus and only be installed in the apparatus before use. The apparatus comprises a main body 101 and a shroud 102 at least partially received within the main body. The shroud is intended to cover the needle of the syringe by moving with respect to the main body to an extended position after use to prevent injuries. A biasing member 103 is arranged within the main body and configured to bias the shroud from a retracted position to the extended position. A plunger arm 104 is provided which is movable between an extended state in which the plunger arm inhibits rotation of the shroud; and a depressed state in which the plunger allows rotation of the shroud and movement of the shroud to the extended position.

[0050] The biasing member drives the shroud linearly in the axial direction towards the extended state. In addition, the shroud is biased to rotate during progression towards the extended state. The rotational biasing can be achieved by cooperating surfaces which are at an angle to the axial direction, such that the axial biasing is partially ‘turned into’ rotational biasing when the cooperating surfaces slide over one another. This example is described in more detail below, whereby the cooperating surfaces are a radial outwards projection 105 on the shroud and an internal surface on the main body. The rotational biasing can also be achieved in other ways, for example by a spring that provides both a linear force and a rotational force, or by a separate rotational biasing means. The path of the shroud is an initial movement along a helical path, following the cooperating surfaces, followed by a linear motion through a linear track. Initially, progression along the helical path is blocked such that the shroud does not deploy until the injection operation by the user is carried out. During the final stage of the injection operation, the block is lifted and the shroud is deployed. The blocking operation can be carried out in different ways. In the example described below, a plunger arm comprises prongs 106 in addition to the plunger itself, whereby the prongs block the helical movement of the shroud. A window 107 is provided in the prongs to let a radial projection of the shroud through towards the end of the stroke. In an alternative example, the block is provided by one or more structural features that are separate from the plunger arm, but which are

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[0053] dislodged towards the end of the stroke by interaction with the plunger arm, such as by the thumb piece of the plunger arm. An advantage of using the movement of the plunger to release the shroud towards the end of the stroke is that release does not require a separate operation and is a natural part of the operation of the device.

[0054] A syringe holder 108 is provided for holding the syringe. The syringe holder may also carry out a function of guiding prongs 106 and further compressing biasing means 103.

[0055] In a different embodiment, the shroud as described above is implemented as a two-part assembly comprising a shroud portion and a drive portion which are separate parts. The shroud portion moves linearly in axial direction under the influence of the drive portion. The drive portion is driven by a biasing member as described above and rotates as described before. The drive portion comprises a projection which engages an angled surface as described above. A helical spring can be used, but the proximal acting surface will be moved distally when compared to the proximal end point of the helical spring illustrated before. The drive portion abuts the shroud portion. A radial projection on the shroud portion may run through a guide rails to prevent rotation, and / or the radial projection will hit a stop to prevent the shroud portion from leaving the main housing. A lock-out mechanism will prevent the shroud portion from being pushed in after deployment. In the following description, a shroud is described as a single part, but it should be kept in mind that it can be implemented as comprising a separate shroud portion and drive portion.

[0056] Figure 2 is a perspective view of a plunger arm 200, corresponding to plunger arm 104 in Figure 1, according to an embodiment. Components visible in Figure 2 include two prongs 201 , a plunger 202, and a thumb mount 203. The two prongs and plunger extend in the same direction and together form a trident. In other embodiments, there may be one prong 201 and the device would work with a single prong, but an advantage of using two prongs is that the forces acting on the plunger arm are more balanced.

[0057] The thumb mount 203 comprises a bottom surface from which the two prongs 201 and plunger 202 protrude. The bottom surface is substantially flat and is perpendicular to a longitudinal axis of the plunger arm 200. The longitudinal axis is defined as passing through the centre of the bottom surface. A skilled person would realise that differently shaped surfaces are available. The thumb mount also comprises a top surface. The top

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[0060] surface has a parabolic cross section along a first direction perpendicular to the longitudinal axis and extending across a significant portion of the top surface. The remainder of the top surface is substantially flat and is parallel to the bottom surface. The parabolic cross section may be suitably shaped to receive a thumb pad of a user. The top surface has a substantially rectangular cross section along a direction perpendicular to the longitudinal axis and first direction. The axial profile of the thumb mount 203 is substantially hexagonal. A skilled person would realise that other shapes are available.

[0061] The plunger 202 is formed from the same piece of material as the thumb mount 203. In other embodiments, the plunger 202 may be mechanically coupled to or fixed to the thumb mount 203. The plunger 202 is collinear to the longitudinal axis. The plunger has a cruciform cross section. A skilled person would realise that other cross sections would also be suitable, such as substantially circular or rectangular. The plunger also comprises a cylindrical foot, collinear to the longitudinal axis. The foot is located at the proximal end of the plunger, away from the thumb mount 203. The cylindrical foot is arranged to act on a bung of the syringe during use.

[0062] The prongs 201 are formed from the same piece of material as the thumb mount 203. In other embodiments, the prongs 201 may be mechanically coupled to or fixed to the thumb mount 203. The prongs 201 are located parallel to the longitudinal axis. The prongs 201 comprise a substantially U-shaped cross section. The cross section of the prongs defines a channel 204. The channel 204 is substantially rectangular or U-shaped. In other embodiments, the cross section may be another shape and thus the channel may also be a different shape. The prongs comprise a radially outward face and two planar faces connected to the radially outward face. The radially outward face has an arc shaped cross section. Each prong defines a window 205. The window is formed on one of the planar faces. The window may have a width approximately equal to half the width of the planar face. The window is only provided on one planar face, whereby the other planar face of the same prong does not have a window. The axial length of the windows may be approximately equal to one fifth of the length of the prongs 201. The windows on the prongs are located radially opposite each other such that the plunger exhibits 180 degree rotational symmetry about the longitudinal axis. The prongs 201 have a longer length than the plunger 202. The radially outward face of each prong comprises two indents 206. One indent is located towards the proximal end of the

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[0065] plunger arm 200 and the other, substantially towards the distal end. The indents have a rectangular cross section.

[0066] Figure 3 presents a perspective view of a syringe holder 300, according to an embodiment. The syringe holder 300 corresponds to syringe holder 108 of Figure 1. The syringe holder comprises a first portion 301 , a second portion 302, and a head 303. The head 303 comprises a hollow cylindrical body and is centred on a longitudinal axis. The head 303 further comprises two shoulders 307 tangentially attached to the head 303. The shoulders have approximately a trapezium cross section. A skilled person would appreciate that differently shaped heads could be used. The shoulders are located radially opposite each other. The head 303 and shoulders comprise a common top surface and a common bottom surface. Each shoulder defines an opening 304. The opening, as viewed from the distal direction, can be characterised by two concentric arcs, each of a different radius, connected by two parallel sides. Additionally, the bottom surface of the head comprises a cut out. The cut out is substantially rectangular in cross section and is located along the radially outward wall of the opening 304 such that the cut out and opening 304 intersect. The cut out has a depth less than the depth of the shoulder 307. The cut out comprises a resiliently deformable tongue 310. The tongue 310 has an arc length substantially equal to the arc length of the cut out where the cut out intersects the opening 304. The tongue 310 has a thickness less than the radial width of the cut out. The tongue is biased radially towards the centre of the syringe holder. The tongue 310 is deformable such that a force applied radially outward can move the tongue 310 such that it is located entirely within the cut out. In other embodiments, there may be only one cut out and tongue.

[0067] The second portion 302 of the syringe holder 300 has a hollow cylindrical body, concentric to the head 303. There are openings at either end of the second portion which have a radius equal to the inner diameter of the second portion. The outer diameter of the second portion 302 is substantially the same as the inner diameter of the head 303. The second portion extends along the majority of the axial length of the syringe holder. The second portion comprises two windows 305 in the sidewalls of the body. The windows are radially opposite each other. The windows extend along the majority of the second portion. The windows are stadium shaped.

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[0070] The first portion 301 of the syringe holder 300 has a hollow cylindrical body, concentric to the head 303 and second portion 302. The first portion 301 has an outer diameter smaller than the outer diameter of the second portion. The first portion 301 is connected to the second portion 302 at the proximal end of the second portion 302. The connection defines a rim 306 with a surface substantially parallel to the bottom and top surfaces of the head 303. The inner diameter of the first portion is smaller than that of the second portion. At the proximal end of the first portion there is an end portion 308. The end portion is circular and has an outer diameter equal to the outer diameter of the first portion 301 . The end defines a circular opening 309. The circular opening has a diameter smaller than the inner diameter of the first portion.

[0071] Figure 4 presents a perspective view of a shroud 400, according to an embodiment. The shroud corresponds to shroud 102 in Figure 1. The shroud comprises a hollow cylindrical body centred along a longitudinal axis. The shroud 400 also comprises two projections 401 extending radially outward from the body. The projections are located radially opposite each other and are located at the distal end of the shroud. The projections are trapezium shaped. In an alternative embodiment, the projections have a round cross section. A distal side of the projection is flush with the distal end of the shroud 400. Two parallel sides of the trapezium shaped projection extend proximally and are parallel to the longitudinal axis. The final side 402 of the projection is at an acute angle to the longitudinal axis. The angle is between 10 and 35 degrees.

[0072] The proximal end of the shroud comprises an opening, of radius equal to the inner diameter of the shroud. Further, the distal end of the shroud comprises an end plate 404. The end plate 404 defines an opening 403. The opening has a smaller diameter than the inside diameter of the shroud.

[0073] Figure 5 presents a side view of a main body 500, according to an embodiment. The main body corresponds to main body 101 in Figure 1 . The main body comprises a torso 501 and two flanges 502. The flanges extend radially outward from the torso. The flanges are located radially opposite each other at the distal end of the torso. The torso and the flanges share a common flat top plane. The bottoms of the flanges are curved. The flanges are designed to receive the index and middle finger. The torso further comprises two stadium shaped windows 503 located radially opposite each other. The outside of the torso tapers towards the proximal end of the torso.

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[0076] Figure 6 is a perspective view of the main body 500. A cylindrical opening 504 runs through a longitudinal axis of the torso. Two further openings, guides 505, run from the distal end through the majority of the length of the torso, parallel to the longitudinal axis. The guides 505 intersect the cylindrical opening. The guides 505 comprise two parallel sides and an arc, centred on the longitudinal axis. A further opening in the distal end of the torso defines two ledges 506 located by the flanges 502. The top of the ledges 506 forms a flat surface. Each ledge has a further cut out which defines an angled surface 507. The angle of the surface is between 10 and 35 degrees with respect to the longitudinal axis. The lower end of the angled surface intersects the guide 505. The surfaces are located radially opposite each other.

[0077] The assembly of the parts of Figures 2-6 shall now be described. A biasing member 103 is inserted into the shroud 102, 400. The biasing member is a spring, specifically a helical compression spring. However, a skilled person would realise than in other embodiments different biasing members could be used. For example, pairs of repelling magnets or tension springs. The shroud is inserted into the cylindrical opening of the main body 101, 501. The outer diameter of the shroud is as the same as or slightly smaller than the inner diameter of the cylindrical opening to ensure a sliding connection. This ensures the shroud has a limited range of movement except along the longitudinal axis. The shroud is inserted such that the angled faces 402 of the projections 401 rest on the angled surfaces 507 of the main body. The interaction between the projections and surfaces initiates rotation of the shroud with respect to the main body when the shroud is biased in the proximal axial direction. In this embodiment, there are two projections and surfaces such that the shroud is mechanically balanced. In other embodiments, one projection and surface may be used, or more than two. The proximal end of the shroud extends out the main body by a small amount. In other embodiments, the shroud may be maintained entirely within the main body before extension. The main body comprises flanges 502. The flanges are configured to receive the index and third finger of a user. The flanges are shaped to have an ergonomic grip which makes the apparatus easier to grip and use.

[0078] The syringe holder 108 is next inserted into the apparatus. The outer diameter of the second part 302 of the syringe holder is the same as or slightly smaller than the inner diameter of the shroud to provide a sliding fit. The outer diameter of the first part 301 of

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[0081] the syringe holder is the same as or slightly smaller than the inner diameter of the helical compression spring. The syringe holder is configured such that the distal end of the spring engages with the rim 306 defined by the first and second part of the syringe holder. Upon insertion of the syringe holder into the shroud and main body, the spring is compressed between rim 306 and shroud end portion 404. The compressed spring biases the shroud in axial directions, but the angle of the projections and corresponding surface on the main body create a rotational bias as well. The compressed spring therefore biases the shroud to rotate from engagement of the projections and surfaces and extend out the proximal end of the main body. The syringe holder is inserted further into the main body until the top of the head of the syringe holder is flush with the top of the main body. The head is received in the opening of the distal end of the main body. The head has a depth substantially the same as the depth of the opening of the distal end of the main body. The windows of the main body and the syringe holder are substantially the same size and are aligned when the syringe holder is fully inserted into the main body. Further, the proximal end of the syringe holder extends out of the main body by a distance less than the distance the shroud extends out of the main body. In other embodiments, the syringe holder may be maintained entirely within the main body. The rim 306 of the syringe holder acts on the spring, and the compression force will therefore not only bias the shroud in proximal direction but apply an equal but opposite biasing force onto the syringe holder. The syringe holder needs to be kept in place, which is achieved by a snap fit between the syringe holder and the main body. The snap fit comprises a tongue or ratchet tooth on one of the two parts of the main body and syringe holder, which slides over and snaps behind a corresponding threshold provided on the other one of the two parts. The device is typically single use, and once the snap fit is activated it cannot be reversed, but the skilled person will be able to implement a reversible fit if needed, such as a friction fit or a snap fit whereby the tongue can be accessed and lifted over the threshold to disengage the two parts.

[0082] A syringe is inserted into the syringe holder next. In some embodiments, the plunger arm is inserted into the syringe holder without inserting the syringe first. The insertion of the plunger arm is described in more detail in a following paragraph.

[0083] The syringe may comprise a needle, needle shield, barrel, and bung. In an embodiment the syringe comprises a barrier. The barrier is provided within a needle hub on the proximal side, while the bung is provided on the distal side. The needle hub fits over a

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[0086] ribbed end of the barrel. Medicament can be included in the internal space defined between the barrel, barrier, and bung. The internal space is sealed and sterile. When pressure is applied by the plunger on the bung, the bung and barrier will move together in the proximal direction. The distal end of the needle extends into the interior space of the needle hub, such that when the barrier moves in the proximal direction within the needle hub, the distal end of the needle pierces the barrier. The medicament can then leave the barrel through the needle, the pressure on the barrier is released and the barrier will be stationary with respect to the barrel and needle hub for the remainder of the operation. The needle hub has a cylindrical shape with an outer diameter less than that of the barrel which is also cylindrical. The syringe may be inserted into the syringe holder with the needle shield attached. The syringe may be inserted without the needle shield. The needle shield may be attached after insertion of the syringe into the syringe holder. The needle and needle shield may be inserted through the openings at the proximal end of the needle holder and shroud and through the centre of the helical compression spring biasing the shroud. The openings are thus large enough to receive the needle and needle shield. The opening at the proximal end of the shroud is larger than the opening at the proximal end of the needle holder. The skilled person, however, would appreciate that the opening at the proximal end of the shroud may be the same size or smaller than the opening at the proximal end of the needle holder. The proximal end of the needle holder is configured to receive the proximal end of the needle and prevent further proximal movement of the syringe. In other embodiments, the first part of the syringe holder may contact the barrel. The second part of the syringe holder has an inner diameter the same as or only slightly larger than the outer diameter of the barrel to ensure a snug fit. The first part of the syringe holder has an inner diameter that is smaller than the outer diameter of the syringe, so that the proximal end of the syringe barrel rests on an internal shoulder between the first part and second part of the syringe holder after the plunger has moved the syringe forwards. In other embodiments, the first part and second part of the syringe holder may have the same internal diameter. This internal diameter may be equal to the outer diameter of the syringe barrel.

[0087] According to an embodiment, a cap is attached to the needle shield. The cap has at least one snap fit latch for engagement with a protruding ring on the needle shield. A skilled person would appreciate that other fixing mechanisms may be used such as adhesives or a friction fit. The protruding ring on the needle shield is located proximally to the shroud. The cap has an internal diameter equal to, or slightly larger, than the outer

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[0090] diameter of the shroud. The shroud is received in an opening in the distal end of the cap. In some embodiments, the cap is not present. The cap has an outer diameter significantly larger than the outer diameter of the needle shield. This makes the cap easier to grip than the needle shield. This provides an ease of use feature for a user. The cap also protects the needle shield during transport, to avoid bending of the needle shield and needle.

[0091] The plunger arm is finally inserted. Figure 7 illustrates the device after complete assembly but prior to use. The two prongs of the plunger arm are received in the openings defined by the head of the syringe holder. The openings in the head of the syringe holder are substantially the same shape as the cross section of the prongs. The guides of main body receive the plunger prongs once the prongs have been inserted through the openings in the head. The cross section of the guides is substantially the same as the cross section of the prongs. Two planar faces of the plunger arm abut the projections of the shroud. The abutment prevents rotation of the shroud with respect to the main body. This prevents axial movement of the shroud and hence prevents the shroud being extended out the proximal end of the main body. The plunger arm is inserted until the tongues 310 of the syringe holder clip into the indents 206 in the prongs. Specifically, the proximal end of the tongue is seated on the proximal edge of the indent. The engagement of the tongues in the indents inhibits axial movement of the plunger arm in the distal direction relative to the main body. Therefore, the plunger is inhibited from being separated from the main body. Since the tongue is secured to the syringe holder at the distal end of the tongue, movement of the plunger arm in the proximal direction pushes the tongue into the cut out such that the tongue does not inhibit movement of the plunger in the proximal direction. In this embodiment, two tongues engage with two indents at a time. The use of two tongues balances the forces on the plunger arm and reduces movement perpendicular to the longitudinal axis. The plunger arm is inserted up to the point where the plunger contacts the bung.

[0092] Figure 8 is a flow diagram which describes a method of assembling the apparatus. As described above, there are 4 important steps to assemble the apparatus. Firstly, S1 , the shroud 102 is inserted into the main body. Secondly, S2, the spring, or other biasing member, is inserted into the shroud. Thirdly, S3, the syringe holder is inserted into the shroud which compresses or primes the biasing member. Finally, S4, the plunger arm is

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[0095] inserted into the main body. The method may comprise further steps, such as attaching a cap, or inserting a syringe.

[0096] The use of the safety syringe will now be described, according to an embodiment. In this embodiment, a syringe has been inserted into the apparatus and a cap has been attached to the needle shield.

[0097] Firstly, the cap is removed by a user. Since the cap is attached to the needle shield by snap fit latches 702, the needle shield is removed with the cap. The needle is thus exposed. The needle is inserted into the injection side by pushing the apparatus proximally towards the injection site.

[0098] The plunger arm is initially in an extended state. The user then pushes the plunger arm towards the main body. In some embodiments this is through use of the user’s thumb, but the device may also be used within an autoinjector whereby the autoinjector pushes the plunger arm towards the main body after the user pushes a trigger. This causes the plunger to contact the bung. In other embodiments, the plunger may already be in contact with the bung, as mentioned above. The plunger arm comprises two prongs to balance the forces. Additionally, the prongs limit movement perpendicular to the longitudinal axis. The plunger has a diameter equal to or less than the inner diameter of the barrel.

[0099] In some embodiments, the syringe inserted into the apparatus comprises a barrier. In this embodiment, putting external pressure on the bung causes the barrier to move forward, as described above, and be pierced by the distal needle part. This causes the medicament in the barrel to be expelled through the needle and into the injection site.

[0100] Once the plunger arm has been fully depressed, the plunger arm is in the depressed state. The tongues of the syringe holder engage with indents located at the distal end of the plunger arm. Thus, the plunger arm is prevented from being withdrawn. The windows in the plunger arm prongs are aligned with the projections of the shroud. Due to engagement of the projections and the surfaces of the main body, the shroud rotates around the longitudinal axis. The projections pass through the windows in the planar faces of the prongs. Further rotation due to inertia is inhibited by the other planar face

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[0103] of the prong. The projections are thus aligned in the channel defined by the prongs of the plunger arm.

[0104] Since the projections are no longer in contact with the surfaces, the shroud can move proximally, biased by the biasing member from a retracted position towards an extended position. The movement is controlled by the projections travelling through the channels defined by the prongs in the plunger arm. The shroud moves proximally until engagement with the area around the injection site. In the absence of a user’s skin body outside the device, the shroud movement continues until the projections reach the end of the track provided by the channels, where they engage with a stop surface. The stop surface is an inner surface of the main body. The windows in the main body and syringe holder allow a user to visually check that the plunger has been moved to the proximal end of the syringe and that the medicament has been delivered. The user can then remove the needle from the injection site and the shroud extends further until the shroud is in an extended position. The shroud is in the extended position when the projections engage with the proximal end of the guides of the main body. The needle is thus covered by the shroud which may prevent accidental needle pricks.

[0105] Optionally, the shroud may include locking features to avoid the shroud being pushed back into the main body against the biasing force of the spring. The locking features may comprise a tongue and indent formation like the ones provided in the plunger arm and syringe holder. Alternatively, the projections on the shroud may move past a tongue, like tongue 310, with the reverse movement being blocked by the tongue.

[0106] Figure 9 is a perspective view of the apparatus after use. The plunger arm 104 is in the depressed state having been fully depressed. The shroud 102 is in the extended position. Thus, the needle is covered by the shroud. The window in the main body 101 of the apparatus allows the user to see the position of the plunger 202 in the barrel of the syringe.

[0107] Figure 10 is a side view of a cross section of the apparatus during use. The plunger arm is in the depressed state and the shroud 102 is in the process of moving to the extended position. The indents 206 located at the distal end of the plunger arm 104 have engaged with the tongues 310 to prevent the plunger arm 104 from being withdrawn from the apparatus. Also visible in Figure 9, is that a window 205 in the plunger arm 104 is aligned

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[0109] 16

[0110] with the angled surface 507 of the main body 101 to allow the projection 401 to move into the channel 204 defined by prong 201 of the plunger arm 104.

[0111] In another embodiment, the biasing member may be primed before inserting the syringe holder. This could be done, for example, by inserting a helical compression spring between the outside of the shroud and the inside of the main body. A rim may be installed on the main body for engagement with the distal end of the spring and a further rim on the shroud may be installed for engagement with the proximal end of the spring.

[0112] In another embodiment, depression of the plunger compresses and primes the biasing member. This could be achieved, for example, by engagement of the distal end of a spring with the proximal end of the prongs of the plunger.

[0113] As a result of the different designs of the abovementioned embodiments, the shapes and sizes of components of the apparatus may be different from those described so far.

[0114] In another embodiment, the prongs may not comprise a channel. The prongs may be solid. The prongs may have a smaller width such that the width of the prongs and the projections may sum to less than the width of the guides of the main body. A channel may instead be provided within the main body.

[0115] In another embodiment, the syringe holder may connect to the main body through use of a snap fit. In an embodiment, ball bearings biased by a biasing member could seat into recesses in the syringe holder. In another embodiment, tongues could engage with indents to secure the syringe holder in the main body.

[0116] Although the invention has been described in terms of preferred embodiments as set forth above, it should be understood that these embodiments are illustrative only and that the claims are not limited to those embodiments. Those skilled in the art will be able to make modifications and alternatives in view of the disclosure which are contemplated as falling within the scope of the appended claims. Each feature disclosed or illustrated in the present specification may be incorporated in the invention, whether alone or in any appropriate combination with any other feature disclosed or illustrated herein.

[0117] 38322478-1

Claims

M&C PX221301GB17CLAIMS:

1. An apparatus for use with a medicament container comprising:a main body;a shroud at least partially received within the main body, wherein the shroud comprises a shroud portion and a drive portion;the shroud portion being movable with respect to the main body between a retracted position and an extended position;a biasing member arranged within the main body and configured to bias the shroud from the retracted position to the extended position;a plunger arm movable between:an extended state in which the plunger arm inhibits rotation of the drive portion; anda depressed state in which the plunger arm allows rotation of the drive portion and movement of the shroud portion to the extended position.

2. The apparatus of claim 1 , wherein the shroud portion is integrally formed with the drive portion to provide said shroud.

3. The apparatus of claim 1 or 2, wherein the drive portion has at least one projection extending radially outwards.

4. The apparatus of claim 3, wherein the projection comprises an angled surface.

5. The apparatus of claim 3 or 4, wherein the body comprises a surface projecting radially inwards, wherein said projection abuts the surface for at least part of said movement of the shroud portion to the extended position.

6. The apparatus of claim 5, wherein the projection comprises a surface with an angle between 10 and 35 degrees with respect to a main longitudinal axis of the apparatus, and wherein said surface has a corresponding angle between 10 and 35 degrees.38322478-1M&C PX221301GB187. The apparatus of claim 5 or 6, wherein said abutting is arranged to impart rotational movement of the drive portion relative to the main body when driven by said biasing member.

8. The apparatus of any one of claims 3 to 7, wherein the plunger arm comprises a syringe plunger and at least one prong and wherein said at least one prong defines a window.

9. The apparatus of claim 8, wherein the prong comprises a U-shaped profile in radial direction, wherein the U-shaped profile arranged to receive the projection.

10. The apparatus of claim 8 or 9, wherein the plunger arm comprises two prongs, wherein each prong defines a window, and wherein the windows are radially opposite to each other.

11. The apparatus of claims 8 to 10, wherein the main body comprises at least one guide channel for receiving said at least one prong.

12. The apparatus of any previous claims, further comprising a syringe holder telescopically arranged within the main body.

13. The apparatus of claim 12, wherein the syringe holder comprises a first portion and a second portion, wherein the first portion has a smaller outer diameter than the second portion.

14. The apparatus of claim 12 or 13, wherein the syringe holder comprises at least one shoulder.

15. The apparatus of claim 14, wherein the at least one shoulder defines an opening for receiving the at least one prong according to claim 8.

16. The apparatus of claim 14, wherein the main body comprises at least one ledge, and wherein the at least one ledge abuts the shoulder.38322478-1M&C PX221301GB1917. The apparatus of any one of claims 12 to 16, wherein the syringe holder is telescopically arranged within the drive portion.

18. The apparatus of any one of the preceding claims, wherein the biasing member is arranged in the interior of the drive portion.

19. The apparatus according to claim 13, wherein the biasing member is arranged around said first portion of the syringe holder and is compressed between an end portion of the shroud and said second portion of the syringe holder.

20. An assembly comprising the apparatus according to any one of the preceding claims, a syringe, a needle shield, and a cap.

21. The assembly of claim 20, wherein the needle shield is mechanically coupled to the syringe and wherein the cap is mechanically coupled to the needle shield.

22. The assembly of claim 21 , wherein the cap is mechanically coupled to the needle shield by at least one snap fit.

23. A method of assembling the apparatus of claims 1 to 22, the method comprising:inserting the shroud in the main body;inserting a spring into the shroud;inserting the syringe holder into the shroud, thereby biasing the spring; inserting the plunger arm into the main body.

24. The method of claim 23, wherein the method further comprises inserting the syringe into a syringe holder.

25. The method of claim 23 or 24, wherein inserting the shroud into the main body comprises aligning the projection of the shroud and the surface of the main body.38322478-1

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