WO2025219550A1

WO2025219550A1 - Syringe having unintentional deployment prevention for a forward deployable sleeve

Info

Publication number: WO2025219550A1
Application number: PCT/EP2025/060696
Authority: WO
Inventors: Erik RYCKALTS; Michele Saputo; Romeo BIANCHI
Original assignee: Roncadelle Operations SRL
Current assignee: Roncadelle Operations SRL
Priority date: 2024-04-17
Filing date: 2025-04-17
Publication date: 2025-10-23
Anticipated expiration: 2026-10-17

Abstract

The current invention relates to a syringe comprising an outer barrel and a spring-loaded protective sleeve deployable from inside said outer barrel to cover a needle of a drug compartment. The assembly is suitable for receiving, use and protect a drug compartment having a distally mounted needle. A triggering element inside the assembly is configured to intermediate pressure exerted upon the drug compartment 10 and a two-stage release of a protective sleeve.

Description

SYRINGE HAVING UNINTENTIONAL DEPLOYMENT PREVENTION FOR A FORWARD DEPLOYABLE SLEEVE

FIELD OF THE INVENTION

The present invention relates to medical and veterinarian devices. In particular, the invention relates to assemblies for injecting fluids.

BACKGROUND

Syringe assemblies having a deployable protective sheath are known in the art. US2003212370 discloses a passive shield system for a syringe. The device includes a spring biased deployable sheath, which when deployed, cover the needle of the syringe. Similar devices are also known from US7682344 and US20080208140. US '344 and US '140 describe a device for protecting an injection device, wherein the complete insertion of the plunger of the injection device causes a protective sheet to be deployed.

The devices from US '370, and the device of US '344 include a two-stage activation step before any protective sheath is deployed. This is attained by means of an arrangement of hooks and abutments which are both difficult to produce and assemble. Furthermore, the multitude of hooks and abutments required by these devices greatly increase the risk of failure of the devices.

Other devices equipped with a deployable protective sheath can be found in US20020120239 and US20020156426. However, the devices disclosed in US '426 and US '239 retain a protective sheath pre-loaded in a retracted position by means of detents. These detents present a first problem related to the considerable force required to override them at the end of an injection. A second problem related to the use of detents is related to their premature disengagement when denser fluids are to be injected. US20050033230 discloses a pre-fillable intradermal delivery device with hidden needle and passive shielding. This device poses the inconvenience that the protective sheath must first be retracted before the syringe can be used, thus obscuring the tip of the needle and resulting in imprecise needle placement, potentially putting the recipient of an injection in danger. Another similar assembly is shown in US7682344, but fails to provide for necessary safety measures that prevent a preliminary deployment of the sleeve, thereby resulting in a device that is very prone to accidental deployment due to shocks, minor manipulations or even small manufacturing defects in dimensions.

The aim of the invention is to provide a device which eliminates those disadvantages. The present invention aims to provide a syringe assembly which is easy to produce, assemble, prepare and use and which is reliable is operation.

SUMMARY OF THE INVENTION

The present invention and embodiments thereof serve to provide a solution to one or more of above-mentioned disadvantages. To this end, the present invention relates to a syringe assembly according to claim 1. The present invention provides an assembly comprising an outer barrel and a spring-loaded protective sleeve deployable from inside said outer barrel. The assembly is suitable for receiving, use and protect a drug compartment having a needle. A triggering element inside the assembly is configured to intermediate pressure exerted upon the drug compartment and a two-stage release of a protective sleeve. This allows for a wide variety of drug compartments to be used while providing for a high level of control over the deployment of the protective sleeve from a retracted position to an extended position wherein said sleeve completely covers the needle of the drug compartment.

Preferred embodiments of the device are shown in any of the claims 2 to 14. These preferred embodiments allow for a better control of the triggering element and its displacement inside the assembly, thereby increasing the reliability of the assembly.

In a second aspect, the present invention relates to a kit according to claim 15.

DESCRIPTION OF FIGURES

The following description of the figures of specific embodiments of the invention is merely exemplary in nature and is not intended to limit the present teachings, their application or uses. Throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. Figure 1 represents an embodiment of the outer barrel of the syringe assembly with a different guide slot than from the invention.

Figure 2 presents in more detail the proximal section of an outer barrel of an embodiment of the syringe assembly with a different guide slot than from the invention.

Figure 3 shows a detailed view of the proximal end of a syringe assembly.

Figure 4 presents an embodiment of a protective sleeve of the syringe assembly.

Figure 5 shows a triggering element having a radially extending lug fitting to the guide slot of Figures 1 and 2.

Figure 6 shows a detailed view of the proximal end of a syringe assembly.

Figure 7 shows the syringe assembly in a pre-activation stage.

Figure 8 shows the syringe assembly in an injection-ready stage.

Figure 9 shows the syringe assembly in a post-injection stage.

Figure 10 shows an embodiment of a syringe assembly including a drug compartment at the end of an injection and prior to the deployment of the sleeve.

Figure 11 shows an embodiment of a syringe assembly including a drug compartment at the end of an injection and after the deployment of the sleeve.

Figure 12 shows the end of the first stage of the disengagement of a hook of a hooking arm from an abutment.

Figure 13 shows the end of the second stage of the disengagement of a hook of a hooking arm from an abutment.

Figure 14 shows a detailed view of the distal end of a syringe equipped with a drug compartment provided with a cap. Figure 15 shows a detailed view of the distal end of a syringe equipped with a drug compartment after removal of a cap.

Figure 16 shows a detailed view of a slit of a sleeve while in retracted position A inside an outer barrel.

DETAILED DESCRIPTION OF THE INVENTION

The present invention concerns a syringe assembly for receiving a drug compartment equipped with a needle at its distal end. The assembly includes a protective sleeve which is advantageously released and provided with a protection against unintentional release, by creating a twofold release mechanism. This can prohibit the system from releasing the protective needle along with removal of a protective cap, which is often strongly connected to the syringe. Removal of the cap has the risk of immediately releasing the triggering element and thereby the sheath, which is to be avoided since it would render the syringe inoperable. Additionally, it can furthermore also provide for a two-stroke release motion of the safety device. The first stroke caused by pressure on the button of the plunger rod of the drug compartment allows the user to fully deliver medicinal fluids without causing further discomfort of damage to the tissues surrounding the injection spot. A second stroke automatically following the first stroke as pressure is removed from the plunger rod causes the protective sleeve to cover the needle, rendering the syringe assembly safe for further handling.

In order to prevent undesired deployment of the syringe assembly (either from cap removal or from a first triggering of the thumb pad), the assembly is advantageously provided with a longitudinally extending slot for guiding a triggering element, which slot is provided with an intermediate passage with a local extremum at the distal surface interposed between a first proximal portion and a second distal portion of said slot. In this way, the syringe assembly can withstand a first 'unintentional' activation (cap removal, inadvertent pressure on the thumb pad), which only makes it ready for the deployment, before releasing of the triggering element in order to render it ready for use.

Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

As used herein, the following terms have the following meanings:

"A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

"Comprise", "comprising", and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

Whereas the terms "one or more" or "at least one", such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment but may refer to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some, but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In a first aspect, the invention provides a syringe assembly for receiving a drug compartment equipped with a needle at its distal end, the syringe assembly comprising: an outer barrel (2) having an internal abutment (4) and a longitudinally extending guide slot (23) near its proximal end; an open-ended sleeve (12), the sleeve being encompassed in said outer barrel and having a bendable hooking arm (13) extending proximally from the proximal end of the sleeve, said hooking arm (13) further comprising a hook (26) laterally extending from the hooking arm (13), said hook (26) being configured to releasably latch onto said internal abutment (4); a compression spring (10) having distal end disposed onto or near the proximal end of the sleeve (12); and an open-ended cylindrical triggering element (18) positioned inside the outer barrel (2) and resting on the proximal end of the spring (10), the triggering element having a distally extending camming tooth (21) configured to contact said hook (26) and cause said hooking arm (13) to laterally deflect in a direction opposite to said hook (26), the cylindrical triggering element (18) further comprises a stop tooth (22), the cylindrical triggering element comprising a radially extending lug complimentary to the longitudinally extending guide slot of the outer barrel.

The longitudinally extending guide slot being complimentary to the radially extending lug of the triggering element, advantageously permits controlling the rotation and the axial displacement of the triggering element. Said guide slot comprises an intermediate passage interposed between a first and a second (straight) longitudinal portion of the slot, the first longitudinal portion being positioned more proximal than the second longitudinal portion on the outer barrel, at least part of the intermediate passage having an inflection portion, wherein the inflection portion comprises a point or segment at which the tangent to the most distal surface at said point or segment is perpendicular to the first and second (straight) longitudinal portions and/or wherein the most distal surface of the inflection portion comprises a portion which slopes towards the proximal end of the outer barrel along the guide slot from the proximal end to the distal end of the outer barrel. The intermediate passage, and more in particular the inflection portion, advantageously permit interrupting the motion of the triggering element in a distal direction. This interruption is highly desirable, as it permits protecting the triggering element against involuntary pressure (by cap removal for instance) and activation, which might result in the accidental and premature deployment of the protective sleeve, thus rendering the syringe assembly useless.

Specifically, the invention relates to a syringe assembly for receiving a drug compartment equipped with a needle at its distal end, the syringe assembly comprising an outer barrel having an internal abutment and a longitudinally extending guide slot near its proximal end, and an open-ended sleeve, the sleeve being encompassed in said outer barrel and having a bendable hooking arm extending proximally from the proximal end of the sleeve, said hooking arm further comprising a hook laterally extending from the hooking arm, said hook being configured to releasably latch onto said internal abutment. The syringe assembly comprises a compression spring having a distal end disposed onto or near the proximal end of the sleeve, biasing the sleeve in a distal direction.

It furthermore comprises an open-ended cylindrical triggering element positioned inside the outer barrel and resting on the proximal end of the spring, the cylindrical triggering element comprising a radially extending lug projecting into the longitudinally extending guide slot of the outer barrel thereby limiting relative movement of the triggering element and the outer barrel, the triggering element having a distally extending camming tooth and a stop tooth.

The guide slot comprises an intermediate passage interposed between a first and a second (straight) longitudinal portion of the guide slot, the first longitudinal portion being positioned more proximal than the second longitudinal portion on the outer barrel, at least part of the intermediate passage having an inflection portion, wherein the inflection portion comprises a point or segment at which the tangent to the most distal surface at said point or segment is perpendicular to the first and second (straight) longitudinal portions and/or wherein the most distal surface of the inflection portion comprises a portion which slopes towards the proximal end of the outer barrel along the guide slot from the proximal end to the distal end of the outer barrel.

When the triggering element is pushed by the spring to the most proximal position relative to the outer barrel where the lug is located at the proximal end of the first longitudinal portion of the guide slot, the hook is latched onto the internal abutment and the sleeve is retracted in the outer barrel.

The camming tooth is configured to deflect the hook laterally in a direction opposite to the hook when the triggering element moves in the distal direction so that the lug moves distally in the second (straight) longitudinal portion, in which position of the triggering element the stop tooth is configured to block the hook from disengaging from the abutment.

The stop tooth releases the hook to disengage from the internal abutment when the triggering element is pushed in a proximal direction by the spring until the lug is in the most proximal position in the second (straight) longitudinal portion and the sleeve is pushed in a distal direction to an extended position by the compression spring in which extended position the sleeve extends past the distal end of the outer barrel.

This provides for an assembly in which the sleeve is preset to extend once the hooking arm is released from the abutment. This is achieved in two phases.

First, the triggering element reaches a certain position as it is depressed (moved distally) during injection, namely during the lug's distal movement in the second (straight) longitudinal portion. At this point, the camming tooth has moved far enough (distally) to have deflected the hook laterally. In doing so, the hook is moved to rest against the stop tooth which has also moved distally (as part of the triggering element). The stop tooth blocks the hook from disengaging from the abutment in this position, as the hook cannot move further laterally. It is however biased to do so due to the compression spring that is in a compressed state and exerting a distally extending force on the hooking arm.

In the second phase, the injection has ended, and the triggering element is no longer pushed distally. The compression spring pushes the triggering element proximally, and with it, also moves the stop tooth proximally, thereby releasing the hooking arm and hook that can disengage from the abutment. The compression spring then extends further, pushing the sleeve, which is now released from the abutment, distally to an extended position in which it would shield a (virtual) needle or syringe. In an embodiment of the invention, the camming tooth of the triggering element is configured to contact the hook (and laterally deflect it) only when the triggering element is advancing distally such that the lug of the triggering element is moving distally in the second (straight) longitudinal portion, but not while the lug is in the first (straight) longitudinal portion or in the intermediate passage.

In a preferred embodiment, the triggering element and outer barrel of the assembly are configured such that the camming tooth is positioned more proximally than the hook (in its entirety) while the lug is in any point of the intermediate passage.

Alternatively, the camming tooth may already extend past the upper bound of the hook while the lug is in the intermediate passage, but with the camming tooth and hook being distanced laterally when the lug is in the intermediate passage, such that the camming tooth and hook do not contact. The transition of the lug from the intermediate passage to the second (straight) longitudinal portion involves a lateral displacement of the lug, which is accomplished by a rotation of the triggering element. Via this rotation, the camming tooth is moved laterally as well and brought in position to contact the hook and laterally deflect it during the distal movement of the triggering element during which the lug moves distally in the second (straight) longitudinal portion.

The sleeve is axially movable inside the outer barrel between a retracted position A and an extended position B. By preference, in position A, the sleeve allows at least 90%, more preferably 100%, of the length of the needle of a drug compartment to be exposed.

In an embodiment, said intermediate passage comprises a first and a second portion, said second portion of the intermediate passage being sloped towards the proximal end of the outer barrel as it extends to the second straight longitudinal portion to connect to the second straight longitudinal portion.

By preference, the first or second portion of the intermediate passage further comprise one or more bumps extending from at least one of the lateral walls of the slot, in this way providing a point of higher resistance to the passage of the radially extending lug. In this way, the safety of the syringe assembly against inadvertent deployment of the sleeve is further increased, in particular during installation of a drug compartment into the syringe assembly or during removal of the cap prior to use. By preference said bump restricts the width of the slot to no less than 80% of the width of the radially extending lug, more preferably no less than 90% of the width of the radially extending lug, in order to create a limited restricting force on the lug as it passes, while still allowing passage.

By preference said bump restricts the width of the slot to a width at most 99% of the width of the radially extending lug, preferably at most 97.5%, even more preferably at most 95%, even more preferably at most 92.5%, even more preferably at most 90% of the width of the radially extending lug.

In an embodiment, said first portion of the intermediate passage is sloped towards the distal end of the outer barrel as it extends to the second straight longitudinal portion to connect to the second portion of the intermediate passage. By preference, said sloped first portion of the intermediate passage has an angle between 5° and 45°. More preferably, said angle is between 10° and 30°, most preferably between 15° and 20°. This advantageously permits avoiding a direct straight passage from the distal end of the first and the second straight longitudinal portion of the slot, which contributes to a deceleration of the triggering element when pushed in a distal direction.

In an embodiment, the intermediate passage comprises a secondary inflection portion, wherein the secondary inflection portion comprises a point or segment at which the tangent to the most proximal surface at said point or segment is perpendicular to the first and second straight longitudinal portions and/or wherein the most proximal surface of the secondary inflection portion comprises a portion which slopes towards the distal end of the outer barrel along the guide slot from the proximal end to the distal end of the outer barrel. By preference, the secondary inflection portion is positioned further along the guide slot from the proximal end to the distal end thereof than the inflection portion. This permits arresting the distally directed motion of the triggering element and prevent unwanted deployment of the sleeve.

In an embodiment, the second portion comprises a raised tooth on its most distal surface preceding to the second portion extending into the second straight portion. This ensures that even when the substantial pressure is applied to the proximal end of the triggering element, the at least one radially extending lug of said triggering element will not reach the proximal end of the second straight portion of the longitudinal slot unless said pressure is removed. In this way, the drug compartment can easily be introduced into the syringe assembly in both highly controlled production environments as well as in the field without any risk of accidental deployment of the protective sleeve.

In an embodiment, the proximal end of the internal abutment of the outer barrel includes a first surface and a second surface, said second surface being angled towards the distal direction of the assembly. In this way, as the triggering element is pressed towards the distal end of the syringe assembly, its lug will bottom out at the distalmost point of the distalmost surface of the said first portion of the intermediate passage and beyond the end of the proximal surface of the first portion of said passage. Once said pressure subsides, the spring will push the triggering element in a proximal direction, causing the at least one lug of the triggering element to enter the second portion of the intermediate passage without possibility of returning to the first portion of said passage. Further pressure exerted by the spring upon the triggering element will cause the at least one lug of the triggering element to align with the second straight longitudinal portion of the slot, rendering the syringe assembly ready for use.

In an embodiment, the triggering element includes a longitudinally extending groove disposed between the camming tooth and the stop tooth. Said clearance groove advantageously provided clearance for the internal abutment of the outer barrel.

In an embodiment, the lug has an at least partly rounded circumference, allowing a smoother guidance through the guide slots. In some versions, only a distal end of the lug's circumference is rounded, as this experiences most of the contact with the guide slot edges, but preferably, the lug is entirely rounded at its circumference.

In an embodiment, the first and the second portions of the longitudinally extending slot are parallel to each other. By preference, the first and the second portions of the longitudinally extending slot are coaxial with each other. This permits obtaining all the advantageous effects of having the intermediate portion of the longitudinal in a more compact space. This results in fewer openings on the outer surface of the outer barrel, which limits the ingress of contaminants and in a much structurally stronger outer barrel.

In an embodiment, the abutment of the outer barrel is configured as a rib extending at least half the length of the outer barrel, said rib being complementary to a longitudinal track on the outer surface of the sleeve. In this way, rotation of the sleeve inside the outer barrel is advantageously prevented, which prevents accidental deployment of the sleeve.

In an embodiment, the sleeve is further equipped with at least one distally extending bendable tab equipped with radially extending hooking tooth, which hooking tooth is complimentary to a distally facing abutment on the inner surface of the outer barrel. In this way, once deployed, the sleeve is advantageously retained in extended position B. This ensures the safety of the user and any bystanders by making the deployment of the sleeve irreversible, thus ensuring the needle becomes and remains covered after use. By preference, said distally facing abutment is the distal end of the barrel, an internal radial lip, most preferably at least one hooking slot near the distal end of the barrel, said at least one hooking slot being preferably substantially perpendicular to the axis of the outer barrel. In order to ensure reliable and effective locking of the sleeve in position B, each bendable tab is bendable between 20° and -20°, more preferably between 20° and -15°, between 15° and - 15°, most preferably between 10° and -10° . In this way, the bendable tabs have enough bending amplitude to override the proximal end of any abutment or slot configured to receive them while having enough resilience to engage and remain engaged to said abutment or slot.

In an embodiment, the hook has a two-part distally directed engagement surface configured to releasably engage with the internal abutment of the outer barrel. The first part of the surface, being substantially perpendicular to the axis of the syringe, is configured to keep the sleeve in position A, preventing its advance under spring pressure, towards position B. The second section located starting near the tip of the hook is rounded but preferably beveled, and configured to allow the hook to slip out of engagement when under spring pressure. In this way, said spring pressure in combination with the beveled or rounded engagement surface of the hook, prevent said hook from returning to full engagement with the internal abutment of the outer barrel. Preferably 40% of the engagement surface of said hook is beveled at an angle of at least 45° relative to said engagement surface, more preferably 50°, most preferably 60°. The hooking arm is configured to deflect between 25° and -25°, more preferably between 20° and -20°, 15° and -20°, most preferably between 10° and -15°. This amplitude permits sufficient deflection of the hooking arm to go from full engagement to full disengagement between the hook and the inner abutment of the outer barrel. The hook of the hooking arm is located between the camming tooth and the stop tooth of the triggering element, the hook of said hooking arm being directed towards the camming tooth. In the first stage the triggering element moves in a distal direction causing partial disengagement of the hook of the hooking arm. Said disengagement of the hook being limited by the stop tooth of the triggering element. In an embodiment, the hook of the hooking arm is substantially triangularly shaped. In this way, the force transfer between the camming tooth and the hooking arm is advantageously made easier. In an embodiment, the stop tooth allows the camming tooth to cause the hooking arm to deflect enough to cause 60%, preferably 70%, most preferably 80% of disengagement of the hook of the hooking arm with the internal abutment of the outer barrel. In this way, the hooking arm deflects enough so that only the beveled or rounded position of the hook engagement surface contact the abutment. In the second stage, the triggering element retracts under spring pressure, until the stop tooth no longer limits further deflection of the hooking arm. This allows the hook of the hoking arm to deflect further due to spring force pushing the sleeve in the distal direction. This spring force causes the hook of the hooking arm to override the internal abutment of the outer barrel, allowing said sleeve to move to extended position B.

The syringe assembly is capable of receiving a drug compartment with a radially extending rim, a distally mounted needle and cap over said needle. Said drug compartment is received into the syringe assembly, distal end first, through the proximal end of the outer barrel. The protective sleeve is, by preference, cylindrical and with an internal diameter large enough to let pass at least the barrel of a drug compartment complete with needle and needle cap. The internal diameter of the sleeve is preferably at least 0.5 mm larger than that of the barrel of the drug compartment to be used with the assembly. In this way, the barrel of said drug compartment is advantageously easy to insert into the protective sleeve. More preferably, the smallest internal diameter of the sleeve is at least 1 mm, 1,5mm most preferably 2mm larger than any the outer diameter of the barrel of the drug compartment.

In an embodiment, the sleeve has a proximal first section. More preferably said first section has a larger outer diameter than a second section distally extending from it. Preferably, said first proximal section of the sleeve has also a larger internal diameter. In this way an abutment is defined at the distal end of the first section of the protective sleeve, said abutment being suitable to be used as a spring abutment for the distal end of the spring. In this way the first section of the sleeve is configured as a spring cavity, which cavity is suitable to receive at least part of the length of the spring in its compressed state. Preferably, the internal diameter of said spring cavity is at least 0.5mm, preferably 1mm larger than the diameter of the spring in its compressed state. This permits avoiding jamming of the spring in the spring cavity. Preferably, the spring abutment is substantially perpendicular to the axis of the syringe.

In an embodiment, the proximal end of the internal abutment of the outer barrel includes a first surface and a second surface, said second surface being angled towards the distal direction of the assembly. The second angled surface advantageously complements the chamfer of the hook of the hooking arm. This further ensures that said hook will not return to full engagement neither during nor after the first stage of the disengagement action of the sleeve. By preference said first and said second surface converge into a proximally facing apex. In this way accidental disengagement of the hook of the hooking arm from the internal abutment of the outer barrel is advantageously avoided.

In an embodiment, the outer barrel is further equipped with at least one bendable prong extending from the distal end of the outer barrel, said prong having a curvature towards the axis of the outer barrel, each of said at least one prong being complementary to a groove on the outer surface of the sleeve. By preference, said the prongs are bendable between 20° and -20, more preferably between 20° and - 15°, between 15° and -15°, most preferably between 10° and -10° . In this way, the at least one prong can deflect outwards when a drug compartment having a cap is inserted into the syringe assembly. Said prong returns to its curved shape once said cap is removed from the distal end of the drug compartment, thereby, advantageously preventing the recapping of the drug compartment. By preference, the outer barrel includes at least two prongs equally spaced around the distal end of the outer barrel. In this way, the force exerted by the prongs upon the cap of the drug compartment is evenly distributed, thereby preventing the drug compartment from skewing from the axis of the syringe and preventing the deployment of the sleeve. By preference, the distal end of the groove is substantially perpendicular to the axis of the syringe, thereby providing an abutment configured to engage the distal end of the at least one prong of the outer barrel. This provides a further or another means of retaining the sleeve in extended position B once it has been deployed. In an embodiment, the outer barrel is further equipped with an internal annular hooking rim disposed to the proximal end of the outer barrel. Said hooking rim comprises one, preferably two, most preferably three or more sections distributed around the proximal end of the outer barrel. The hooking rim is configured to engage with the radially extending rim of a drug compartment, and in this way, retain said drug compartment once it has been inserted into the barrel. This prevents the drug compartment from accidentally falling from the syringe assembly, and in the process damaging said drug compartment and/or exposing the needle of the drug compartment.

The triggering element preferably comprises an internal rim, the distal surface of said rim being configured as an abutment against which the proximal end of the compression spring rests. In this way, the triggering element and the proximal end of the sleeve are located at opposite ends of the compression spring. In this way, the spring advantageously keeps the triggering element under tension against the hooking rim, said compression spring biasing the sleeve in the distal direction. The hook of the hooking arm of the sleeve being configured hook onto the abutment to hold the sleeve in a retracted position against said tension of the compression spring. Movement of the triggering element in a distal direction brings the camming tooth in contact with a proximal surface of the hook of the hooking arm. Further displacement of the triggering element in the distal direction causes said hooking arm to laterally deflect against the stop tooth in a direction opposite to said hook, pushing the hook into the sloped second surface of the abutment. Once the hook of the hooking arm enters the sloped second surface of the abutment, the sleeve is allowed to move in a distal direction, under tension of the compression spring, a fraction of the length of said sloped second surface of the abutment. Full deflection of hooking arm is impeded by the stop tooth of the triggering element, thus keeping the hook of the hooking arm from fully disengaging the sloped second surface of the abutment. The triggering element is further configured to retract under spring pressure as pressure in the distal direction exerted upon the triggering element is eased and/or removed. In this way the triggering element retracts until the stop tooth no longer limits further deflection of the hooking arm allowing the hook to deflect further, due to spring force and the sloped second surface of the abutment, in this way the hook overrides the abutment and the compression spring pushes the sleeve in the distal direction. The inner diameter of the triggering element is configured to be larger than the diameter of barrel of a drug compartment, but smaller than the radially extending flange or annular rim of said drug compartment. This permits easy assembly of a drug compartment by inserting the distal end of said drug compartment through the proximal end of the outer barrel of the syringe, allowing the barrel of the drug compartment to pass through the inner diameter of the triggering element and the inner diameter of the sleeve, the length of the outer barrel and sleeve are such that at least the needle, either capped or exposed, protrudes out the distal end of the outer barrel and sleeve, the hooking rim is configured to retain the flange or annular rim of the drug compartment against the proximal end of the triggering element. In this way, the syringe assembly can be provided either separate from the drug compartment as well as with a drug compartment already attached, without compromising in any way the function and safety of the syringe assembly. When in use, the syringe assembly is easy and intuitive to use and does not leave the user in doubt regarding the state of the syringe assembly. When a drug compartment is attached to the syringe assembly, pressure exerted upon the plunger of said drug compartment is advantageously transmitted to the triggering element by means of the radially extending flange or annular rim of the drug compartment. In this way, the syringe assembly advantageously gives the user full control over when the protective sleeve is deployed based only on the pressure exerted upon the plunger of the drug compartment. For example, the user may choose not to deploy the sleeve immediately after an injection while the needle is still in or near the skin of the injection recipient, option instead to release pressure on the plunger once the needle has been fully retracted and away from the skin of the patient. In this way, the user is easily able to prevent impacting the skin of the patient with the sleeve as it is deployed. This is of particular importance when dealing with sensitized skin or easily damageable tissues.

A second aspect of the invention relates to a kit including the syringe assembly according to at least one embodiment of the first aspect, the kit comprising: a syringe assembly according to the first aspect of the invention; a prefilled drug compartment having a stopper, needle mounted the distal end of the drug compartment, a cap covering the needle; and a plunger rod surmounted by a button, the plunger rod being suitable to be inserted into the proximal end of the drug compartment to push the stopper.

The kit provides a convenient and hygienic means of transporting and storing the syringe assembly and drug compartment until its use. In this configuration of the kit, the user can prepare the syringe for use by inserting the drug compartment, distal end first. The drug compartment is passed first into the proximal end of the syringe assembly, through the proximal end of the outer barrel, then the proximal end of the protective sleeve until the radially extending rim of the drug compartment engages with hooking rim at the proximal end of the outer barrel. The plunger rod is then inserted through the proximal end of the drug compartment until making contact with the stopper. The cap of the drug compartment can then be removed to expose the syringe. In an embodiment, the syringe assembly and drug compartment may also be provided packages separately. This embodiment of the kit provides substantial flexibility of use as the user can still choose from a variety of drug compartments and simply install the desired drug compartment into the assembly.

By preference, the kit is provided in a sterilized package, said package being by preference a box, a blister pack, most preferably a carded blister pack. Most preferably, the package is under a vacuum. Each package may contain one or more kits. Preferably, the kit is provided with the drug compartment inserted into the syringe assembly. In this way the kit is advantageously faster to put in use while maintaining its dimensions advantageously compact. By preference, the kit is provided with the plunger rod inserted into the drug compartment. This makes it even faster to put the kit in use, which is particularly advantageous in emergency situations and/or one-handed operation of the syringe.

The invention is further described by the following non-limiting examples which further illustrate the invention, and are not intended to, nor should they be interpreted to, limit the scope of the invention.

DESCRIPTION OF FIGURES

With as a goal illustrating better the properties of the invention the following presents, as an example and limiting in no way other potential applications, a description of a number of preferred embodiments of the syringe assembly, wherein:

FIG. 1 represents an embodiment of the outer barrel (2) of the syringe assembly (1). The figures show a guide slot (23) and a hooking rim (7) near the proximal end of the outer barrel (2). A hooking slot (8) is shown near the distal end of the outer barrel (2). Two distally extending prongs (9) are shown curved towards the axis of the outer barrel (2). The guide slot (23) in this figure is not representative of that of the invention. FIG. 2 presents in more detail the proximal section of an outer barrel (2) of an embodiment of the syringe assembly (1). The figure shows the internal abutment

(4) extending in a distal direction and forming a rib (6). The distal end of said abutment (3)/rib (6) are shown comprising two surfaces converging into an apex

(5), one of said surfaces being a sloped face (4) extending from said apex (5) and descending towards the distal end of the outer barrel (2). The abutment (3)/rib (6) is shown substantially aligned with the guide slot (23), said guide slot (23) being partially surrounded by a flexible tab. A second guide slot (23) is shown. A hooking rim (7) is shown interposed between said two guide slots (23). The guide slot (23) in this figure is not representative of that of the invention.

FIG. 3 shows a detailed view of the proximal end of a syringe assembly (1). The figure shows the distal end of the syringe (1) when the sleeve (12) is in retracted position A. The hook (26) of the hooking arm (13) of the sleeve (12) is shown fully engaging the proximal end of the abutment (3)/rib (6), the tip of said hook (26) resting near the apex (5) of the abutment (3)/rib (6). The spring (10) is shown with its distal end resting against the spring abutment (29) inside the spring compartment (27) of the sleeve (12). The proximal end of said spring is shown resting against the internal rim (30) of the triggering element (18). In this way, the spring (10) is biasing the triggering element (18) in a proximal direction and the sleeve (12) in a distal direction. Track (20) of the sleeve (12) is shown engaging with the rib (6) of the outer barrel (2), thereby preventing said sleeve (12) from rotating. The figure shows also the distal-most end of a camming tooth (21) in close alignment with the distal- most end of the sloped face (4) of the abutment (3)/rib (6).

FIG. 4 presents an embodiment of the protective sleeve (12) of the syringe assembly (1). The sleeve (12) is shown as provided with two hooking arms (13) each provided with a laterally extending tooth (26). A track is (20) adjacent to each hooking arm (13), each of said tracks (20) being overlapped by the tooth (26) of the adjacent hooking arm (13). A larger diameter proximal end of the sleeve (12) defines a spring compartment (27), the distal end of said compartment defines a spring abutment (29). Two diametrically opposed bendable hooking tabs (14) are shown extending distally from the distal end of the spring compartment (27). A hooking tooth (28) extends radially from the distal end of each of said bendable hooking tabs (14). A groove (15) complete with a distal locater groove abutment (16) is shown located about halfway through the length of the sleeve (12). Two slits (17) located at the distal end of the sleeve (12) provide clearance for each of the prongs (9 not shown) of the outer barrel (2 not shown).

FIG. 5 shows a triggering element (18). The triggering element (18) is shown including two radially extending lugs (19), two distally extending camming teeth (21) and two distally located stop teeth (22), each pair of camming tooth (21) and stop tooth (22) being intercalated by a clearance groove (31). An internal rim (30) near the proximal end of the triggering element (18) provided an abutment for the proximal end of the spring (10). The radially extending lugs (19) are configured to fit into the guide slot (23) of the outer barrel (2) of FIGS. 1 and 2, although it is also usable in combination with the outer barrel (2) of FIGS. 7 - 9. However, for the outer barrel (2) of FIGS 7 - 9, a rounded (bottom of the) lug (19) would be more advantageous in order to be guided more smoothly through the curved trajectory of the guide slot (23).

FIG. 6 shows an embodiment of a syringe assembly (1) including a drug compartment (32) at the end of an injection and prior to the deployment of the sleeve (12). A drug compartment (32) is shown held inside the syringe (1) by means of a hooking rim (7) engaging the distal end of a radially extending rim (36) of said drug compartment (32). The drug compartment (32) is shown comprising a needle (24) distally extending from the distal end of the drug compartment (32). The drug compartment (32) is shown further comprising a plunger rod (33) surmounted by a button (34) and a stopper (35) extending distally from said piston rod (33), the stopper (35) being shown fully inserted into the drug compartment (32). The figure shows the distal surface of the rim of the drug compartment (36) contacting the proximal end of the triggering element (18) and ready to start the first stage of disengagement of the hook (26 not shown) of the hooking arm (13 not shown).

FIG. 7 shows the syringe assembly (1) in a pre-activation stage. The figure shows the syringe assembly (1) equipped with a drug compartment (32), the distal surface of the rim of the drug compartment (36) is shown resting on the proximal end of the triggering element (18). The lug (19) of the triggering element (18) is shown in the process of moving towards an intermediate passage (38) of the longitudinally extending guide slot (23) before reaching a first portion (40) of said intermediate passage (38) of the guide slot (23). This process of moving can for instance be initiated by removal of the cap, thereby pulling along the syringe to which it is connected. FIG. 8 shows the syringe assembly (1) in an injection-ready stage. Once further pressure is applied onto the plunger (34) while in the state described in figure 7, the lug (19) of the triggering element (18) travels along the first portion (40) of the intermediate passage (38) of the longitudinally extending guide slot (23). By releasing said pressure, said lug (19) is laterally displaced by way of the proximal end of the second portion (41) of the intermediate passage (38) of the longitudinally extending guide slot (23), and ultimately meeting the proximal end of the second portion (39) of the longitudinally extending guide slot (23). In this position, the syringe assembly (1) is ready to perform an injection.

FIG. 9 shows the syringe assembly (1) in a post-injection stage. The figure shows the button (34) in a fully depressed position relative to the drug compartment (32), and after the deployment of the protective sleeve (12). This is the final state of the syringe assembly (1), after which it can be safely handled without the risk of needle (24) puncture, and finally disposed of.

In FIGS. 7 - 9, the guide slot (23) thus comprises a first (longitudinal) portion (37) at the proximal end, which transitions into the intermediate passage (38), which then transitions into the second (longitudinal) portion (39), as the triggering element (18) is depressed distally and released in a first stage. The intermediate passage (38) comprises a first portion (40) of the intermediate passage (38) which extends mainly distally (and laterally) from the first (longitudinal) portion (37), and it comprises a second portion (41) of the intermediate passage (38), which extends proximally (and laterally) from the first portion (40) of the intermediate passage (38), and transitions into the second portion (39) of the guide slot (23).

FIG. 10 shows an embodiment of a syringe assembly (1) including drug compartment (32) at the end of an injection and after the deployment of the sleeve (12). The figure shows the sleeve (12) in advanced position B, the hooking teeth (28) of the bendable hooking tabs (14) are shown engaging the hooking slots (8) of the outer barrel (2). In this state, retraction of the sleeve (12) is impossible by virtue of the engagement of the hooking teeth (28) of the bendable hooking tabs (14) onto the hooking slots (8) of the outer barrel (2).

FIG. 11 shows the end of the first stage of the disengagement of a hook (26) of a hooking arm (13) from an abutment (3). The figure shows the triggering element (18) in a fully depressed state. A camming tooth (21) is show in contact with the proximal end of the hooking arm (13), which hooking arm (13) is deflected against the stop tooth (22). Said deflection is enough to cause the beveled tip of the hook (26) to pass the apex (5) of the abutment (3) and engage the sloped surface (4) of the abutment (3).

FIG. 12 shows the end of the second stage of the disengagement of a hook (26) of a hooking arm (13) from an abutment (3). The figure shows the triggering element (18) in a retracted position, undepressed position. In this position, the stop tooth (22) no longer limits further deflection of the hooking arm (13), allowing pressure of the spring (10 not shown) to cause the beveled tip of the hook (26) to override the sloped surface (4) of the abutment (3)/rib (6). The sleeve (12) is now free to advance to position B.

FIG. 13 shows a detailed view of the distal end of a syringe (1) equipped with a drug compartment (32) provided with a cap (25). The figure shows two prongs (9) extending from the distal end of the syringe (1), which prongs (9) are outwardly deflected by said cap (25).

FIG. 14 shows a detailed view of the distal end of a syringe (1) equipped with a drug compartment (32) after removal of a cap (25). The figure shows two prongs (9) extending from the distal end of the syringe (1), which prongs (9) are now shown deflected back to their natural curvature towards the axis of the syringe (1). In this natural curvature, the tips of the prongs (9) are distanced sufficiently close to each to preclude re-installation of the cap (25) over the needle (24).

FIG. 15 shows a detailed view of a slit (17) of a sleeve (12) while in retracted position A inside an outer barrel (2). The figure shows how the slit (17) provides clearance for the prong (9), allowing said prong (9) to maintain its natural curvature towards the axis of the syringe (1).

FIG. 16 shows a sleeve (12) locked in extended position B by a prong (9) and a hooking tooth (28) of a bendable hooking tab (14 not shown). The figure shows the distal end of the prong (9) engaging the groove abutment (16) of the groove (15) of the side of the sleeve (12). The figure further shows said hooking tooth (28) of a bendable hooking tab (14 not shown) engaging a hooking slot (8) near the distal end of the outer barrel (2). The present invention is in no way limited to the embodiments described in the examples and/or shown in the figures. On the contrary, methods according to the present invention may be realized in many different ways without departing from the scope of the invention.

List of numbered items:

1 syringe assembly

2 outer barrel

3 abutment

4 sloped face

5 apex

6 rib

7 hooking rim

8 hooking slots

9 prongs

10 spring

12 sleeve

13 hooking arm

14 bendable hooking tabs

15 groove

16 groove abutment

17 slit

18 triggering element

19 lug

20 track

21 camming tooth

22 stop tooth

23 guide slot

24 needle

25 cap

26 hook

27 spring compartment

28 hooking tooth

29 spring abutment

30 triggering element rim

31 clearance groove 32 drug compartment

33 plunger rod

34 plunger button

35 stopper 36 annular rim of the drug compartment

37 first portion of the longitudinally extending guide slot

38 intermediate passage of the longitudinally extending guide slot

39 second portion of the longitudinally extending guide slot

40 first portion of the intermediate passage 41 second portion of the intermediate passage

Claims

1. A syringe assembly (1) for receiving a drug compartment (32) equipped with a needle (24) at its distal end, the syringe assembly comprising: an outer barrel (2) having an internal abutment (4) and a longitudinally extending guide slot (23) near its proximal end; an open-ended sleeve (12), the sleeve being encompassed in said outer barrel and having a bendable hooking arm (13) extending proximally from the proximal end of the sleeve, said hooking arm (13) further comprising a hook (26) laterally extending from the hooking arm (13), said hook (26) being configured to releasably latch onto said internal abutment (4); a compression spring (10) having a distal end disposed onto or near the proximal end of the sleeve (12), biasing the sleeve in a distal direction; and an open-ended cylindrical triggering element (18) positioned inside the outer barrel (2) and resting on the proximal end of the spring (10), the cylindrical triggering element comprising a radially extending lug (19) projecting into the longitudinally extending guide slot of the outer barrel thereby limiting relative movement of the triggering element and the outer barrel, the triggering element having a distally extending camming tooth (21) and a stop tooth (22); characterized in that, said guide slot comprises an intermediate passage (38) interposed between a first (37) and a second (39) straight longitudinal portion of the guide slot, the first longitudinal portion being positioned more proximal than the second longitudinal portion on the outer barrel, at least part of the intermediate passage having an inflection portion, wherein the inflection portion comprises a point or segment at which the tangent to the most distal surface at said point or segment is perpendicular to the first and second straight longitudinal portions and/or wherein the most distal surface of the inflection portion comprises a portion which slopes towards the proximal end of the outer barrel along the guide slot from the proximal end to the distal end of the outer barrel, wherein when the triggering element is pushed by the spring to the most proximal position relative to the outer barrel where the lug is located at the proximal end of the first longitudinal portion of the guide slot, the hook is latched onto the internal abutment and the sleeve is retracted in the outer barrel, wherein the camming tooth is configured to deflect the hook laterally in a direction opposite to the hook when the triggering element moves in the distal direction so that the lug moves distally in the second straight longitudinal portion, in which position of the triggering element the stop tooth is configured to block the hook from disengaging from the abutment, and wherein the stop tooth releases the hook to disengage from the internal abutment when the triggering element is pushed in a proximal direction by the spring until the lug is in the most proximal position in the second straight longitudinal portion and the sleeve (12) is pushed in a distal direction to an extended position by the compression spring (10) in which extended position the sleeve extends past the distal end of the outer barrel.

2. The assembly according to previous claim 1, characterized in that, said intermediate passage comprises a first (40) and a second (41) portion, said second portion of the intermediate passage being sloped towards the proximal end of the outer barrel as it extends to the second straight longitudinal portion to connect to the second straight longitudinal portion.

3. The assembly according to previous claim 2, characterized in that, said first portion of the intermediate passage is sloped towards the distal end of the outer barrel as it extends to the second straight longitudinal portion to connect to the second portion of the intermediate passage,

4. The assembly according to any of previous claims 2 or 3, wherein the intermediate passage comprises a secondary inflection portion, wherein the secondary inflection portion comprises a point or segment at which the tangent to the most proximal surface at said point or segment is perpendicular to the first and second straight longitudinal portions and/or wherein the most proximal surface of the secondary inflection portion comprises a portion which slopes towards the distal end of the outer barrel along the guide slot from the proximal end to the distal end of the outer barrel.

5. The assembly according to previous claim 4, wherein the secondary inflection portion is positioned further along the guide slot from the proximal end to the distal end thereof than the inflection portion.

6. The assembly according to any of the previous claims 1-5, characterized in that, the second portion comprises a raised tooth on its most distal surface preceding to the second portion extending into the second straight portion.

7. The assembly according to any of the previous claims, characterized in that, the proximal end of the internal abutment of the outer barrel includes a first surface and a second surface, said second surface being angled towards the distal direction of the assembly.

8. The assembly according to any of the previous claims, characterized in that, the triggering element includes a longitudinally extending groove disposed between the camming tooth and the stop tooth.

9. The assembly according to claim any of the previous claims, characterized in that, the first and the second portions of the longitudinally extending slot are parallel to each other.

10. The assembly according to previous claim 10, characterized in that, the first and the second portions of the longitudinally extending slot are coaxial with each other.

11. The assembly according to any of the previous claims 1-7, characterized in that, the abutment of the outer barrel is configured as a rib extending at least half the length of the outer barrel, said rib being complementary to a longitudinal track on the outer surface of the sleeve.

12. The assembly according to any of the previous claims 1-9, characterized in that, the sleeve is further equipped with at least one distally extending bendable tab equipped with radially extending hooking tooth, which hooking tooth is complimentary to a distally facing abutment on the inner surface of the outer barrel.

13. The assembly according to any of the previous claims 1-11, characterized in that, the outer barrel is further equipped with at least one bendable prong extending from the distal end of the outer barrel, said prong having a curvature towards the axis of the outer barrel, each of said at least one prong being complementary to a groove on the outer surface of the sleeve.

14. The assembly according to any of the previous claims, characterized in that, the outer barrel is further equipped with an internal annular hooking rim disposed to the proximal end of the outer barrel.

15. Kit including the syringe assembly, the kit comprising: a syringe assembly according to any one of the claims 1 to 14; a prefilled drug compartment having a stopper, needle mounted the distal end of the drug compartment, a cap covering the needle; and a plunger rod surmounted by a button, the plunger rod being suitable to be inserted into the proximal end of the drug compartment to push the stopper.