WO2024089000A1

WO2024089000A1 - Syringe with a forward deployable sleeve

Info

Publication number: WO2024089000A1
Application number: PCT/EP2023/079561
Authority: WO
Inventors: Erik RYCKALTS
Original assignee: Roncadelle Operations Srl
Priority date: 2022-10-25
Filing date: 2023-10-24
Publication date: 2024-05-02

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 and a two stage release of a protective sleeve.

Description

SYRINGE WITH 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. 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 12. A specific preferred embodiment relates to an invention according to claim 4, wherein the triggering element is further equipped with a radially extending lug. Yet another preferred embodiment is disclosed in claim 5, wherein the outer barrel of the assembly is provided with a guide slot near its proximal end. 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 13. Preferred embodiments of the kit are shown in any of the claims 14 to 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. Figure 2 presents in more detail the proximal section of an outer barrel of an embodiment of the syringe assembly.

Figure 3 presents an embodimentof a protective sleeve of the syringe assembly.

Figure 4 shows a triggering element.

Figure 5 shows a detailed view of the proximal end of a syringe assembly.

Figure 6 shows an embodiment of a syringe assembly including drug compartment at the end of an injection and prior to the deployment of the sleeve.

Figure 7 shows an embodiment of a syringe assembly including drug compartment at the end of an injection and after the deployment of the sleeve.

Figure 8 shows the end of the first stage of the disengagement of a hook of a hooking arm from an abutment.

Figure 9 shows the end of the second stage of the disengagement of a hook of a hooking arm from an abutment.

Figure 10 shows a detailed view of the distal end of a syringe equipped with a drug compartment provided with a cap.

Figure 11 shows a detailed view of the distal end of a syringe equipped with a drug compartment after removal of a cap.

Figure 12 shows a detailed view of a slit of a sleeve while in retracted position A inside an outer barrel.

Figure 13 shows a sleeve locked in extended position B by a prong and a hooking tooth of a bendable hooking tab.

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 by means of a two stroke motion. 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.

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.

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, definitions for the terms used in the description are included to better appreciate the teaching of the present invention. The terms or definitions used herein are provided solely to aid in the understanding of the invention.

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. 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 having an internal abutment near its proximal end; an open-ended sleeve, the sleeve being encompassed in said outer barrel and having a bendable hooking arm extending proximally form the proximal end of the sleeve; and a compression spring having distal end disposed onto or near the proximal end of the sleeve.

The assembly further comprises an open-ended cylindrical triggering element positioned inside the outer barrel and resting on the proximal end of the spring, the triggering element having a distally extending camming tooth and a stop tooth, said camming tooth being configured to contact a hook laterally extending from the hooking arm and cause said hooking arm to laterally deflect in a direction opposite to said hook. The triggering element is held in place on the proximal end by a hooking rim, the internal diameter of said hooking rim having a smaller diameter than the outer diameter of the triggering element. The proximal end of the hooking rim being advantageously sloped, narrowing towards the distal direction of the outer barrel, and in this way, advantageously, making the assembling of the syringe assembly substantially easier, thus easily permitting both manual and automated assembling.

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 compressions 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.

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, 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 or, 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 triggering element includes a longitudinally extending clearance groove disposed between the camming tooth and the stop tooth. Said clearance groove advantageously prevents rotation of the triggering element, while providing clearance for the internal abutment of the outer barrel.

In an embodiment, the triggering element is further equipped with a radially extending lug. Most preferably, the proximal end of the outer barrel comprises a longitudinally extending guide slot complimentary to the radially extending lug of the triggering element. This permits controlling the rotation and the axial displacement of the triggering element. The guide slot may be straight, curved or both. By preference, said guide slot is straight as it advantageously simpler to produce and reduces friction with the at least one lug of the triggering element during the two-stage disengagement of the hooking arm from the internal abutment of the 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. By preference, the sleeve is equipped with a longitudinal track on its outer surface, said track being complementary to the rib. 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 a radially extending hooking tooth. By preference, the outer barrel further comprises an distally facing abutment complementary to the at least one hooking tooth of the sleeve. 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 outer barrel is further equipped with at least one bendable prong extending from the distal end of the outer barrel, said prongs having a curvature towards the axis of the outer barrel. 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.

In an embodiment, the sleeve has at least one groove on its outer surface, said groove being complementary to the distal end of at least one prong. 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.

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; a prefilled drug compartment having a stopper, a needle mounted at 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.

In an embodiment, 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.

In an embodiment, 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 shows 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). 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 a 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).

FIG. 3 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. 4 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).

FIG. 5 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. 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 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. 8 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. 9 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. 10 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. 11 shows 10 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. 12 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. 13 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 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

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) near its distal end; an open-ended sleeve (12), the sleeve being encompassed in said outer barrel and having a bendable hooking arm (13) extending proximally form the proximal end of the sleeve; and a compression spring (10) having distal end disposed onto or near the proximal end of the sleeve (12); characterized in that, the assembly further comprises 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) and a stop tooth (22), said camming tooth being configured to contact a hook (26) laterally extending from the hooking arm (13) and cause said hooking arm to laterally deflect in a direction opposite to said hook.

2. The assembly according to previous claim 1, 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.

3. The assembly according to any of the previous claims 1-2, characterized in that, the triggering element includes a longitudinally extending groove disposed between the camming tooth and the stop tooth.

4. The assembly according to any of the previous claims 1-2, characterized in that, the triggering element is further equipped with a radially extending lug.

5. The assembly according to previous claim 4, characterized in that, the proximal end of the outer barrel comprises a longitudinally extending guide slot complimentary to the radially extending lug of the triggering element.

6. The assembly according to any of the previous claims 1-5, characterized in that, the abutment of the outer barrel is configured as a rib extending at least half the length of the outer barrel.

7. The assembly according to previous claim 6, characterized in that, the sleeve is equipped with a longitudinal track on its outer surface, said track being complementary to the rib.

8. The assembly according to any of the previous claims 1-7, characterized in that, the sleeve is further equipped with at least one distally extending bendable tab equipped with radially extending hooking tooth.

9. The assembly according to previous claim 8, characterized in that, the outer barrel further comprises a distally facing abutment complementary to the at least one hooking tooth of the sleeve.

10. The assembly according to any of the previous claims 1-9, 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.

11. The assembly according to previous claim 10, characterized in that, the sleeve has at least one groove on its outer surface, said groove being complementary to the distal end of at least one prong.

12. 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.

13. Kit including the syringe assembly according to any of the claims 1-12, the kit comprising: a syringe assembly; 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;

14. The kit according to claim 13, characterized in that, the kit is provided with the drug compartment inserted into the syringe assembly.

15. The kit according to any of the previous claims 13-14, characterized in that, the kit is provided with the plunder rod inserted into the drug compartment.