Syringe with improved needle retraction mechanism

Abstract

The invention relates to a syringe with an improved needle retraction mechanism, the syringe comprising: (a) a cylindrical barrel, (b) a needle holder, (c) a hollow plunger, (d) a rod, (e) an extractor element and (f) a restoring tension or compression spring, said extractor element being movably displaceable from an advanced position to a retracted position, said extractor element having a male protrusion and a hooking device, said male protrusion to engage said inner cavity of said needle holder to engage said extractor element to said needle holder; said hooking device defining a connection between said plunger and said extractor element, and wherein an axial bore of said plunger is defined by a plurality of bendable flanges, said bendable flanges being configured to slide over said needle holder, said bendable flanges thereby bending outwards and expanding said axial bore of said plunger, and whereby said extractor element is disconnected from said plunger and retracted towards its retracted position. The invention further relates to a syringe kit, wherein the syringe is provided with an improved needle retraction mechanism as described herein.

Description

TECHNICAL FIELD

[0001] The present invention relates to a safety syringe with a retractable needle.

[0002] More specifically, the present invention relates to a syringe with an improved needle retraction mechanism. BACKGROUND

[0003] Medical syringes are well known in the art and include a wide variety of designs, each having its particular advantages and applications. One particular type of syringe relates to so-called safety syringes, which are used to protect medical personnel and others from accidental needle stick injuries and to prevent reuse of the syringe. The dangers associated with the reuse of a used syringe and the problems caused by disposal of the syringe in public places are well known. In recent years, the importance of safety syringes has increased as many governments and safety agencies have become concerned with needle stick injuries and the prevention of reuse.

[0004] However, a general problem associated with current safety syringes is their relative complexity and / or unclear operation. Medical personnel operating a safety syringe often are unsure how to engage the mechanism that retracts the needle and / or the mechanism that safely locks the needle within the syringe. Furthermore, even if the mechanisms have been engaged, the medical personnel doubts whether the needle has been properly retracted and / or whether the retraction has been completed at all. Moreover, current retraction mechanisms make the syringe design unnecessarily complex and inherently cause some other drawbacks, for example, a general lack of liquid and / or air tightness and an inaccurate liquid metering. These drawbacks add additional uncertainty to the medical personnel, as he or she cannot be sure of the exact amount of the injection anymore.

[0005] A safety syringe with a retractable needle is exemplified in EP 0 505 330. Although this syringe includes a working needle retraction mechanism, the medical personnel is required to be provided with detailed instructions on how to properly operate the syringe. Whereas operating a normal syringe simply includes pushing the plunger rod until the syringe is empty, the syringe design according to EP '330 requires careful handling. In a first pushing stroke, the syringe is emptied. However, in order to engage the retraction mechanism, the operator also needs to explicitly push the plunger rod during a second pushing stroke. Moreover, the need for said second pushing is not only counterintuitive, but also highly unclear when the needle retraction is engaged and whether it is completed at all. In addition to this, the retraction mechanism according to EP '330 is a two-stage retraction: first, the needle holder is coupled to the extractor element, only in a second stage, the retraction mechanism is engaged and actually retracts the needle. Thus, it can be voluntary or involuntary for the operator to only partially engage the mechanism.

[0006] US 5 190 526 discloses another safety syringe. The retraction mechanism is rather complex as the wall of the syringe barrel is shaped so as to fit a number of ball bearings. The unusual shape of the syringe barrel inevitably reduces the liquid and / or air tightness between the plunger and the barrel and substantially reduces the volume accuracy of the liquid dose. Thus, a medical practitioner operating the syringe according to US '526 will not be certain of the exact amount of the injection. Furthermore, as the retraction mechanism of US '526 comprises two stages of retraction, the operator will not be certain that the retraction mechanism has been properly engaged. WO 91 / 03269 and EP 2229968 also describe a syringe with a safety retraction mechanism. JP H05 503437 describes a pre-filled syringe.

[0007] The present invention aims at solving at least some of the above-mentioned problems and drawbacks. SUMMARY

[0008] The present invention and its embodiments serve to provide a solution to one or more of the above-mentioned drawbacks. To this end, the present invention relates to a syringe with an improved needle retraction mechanism according to claim 1, which has the advantage that it can be intuitively operated for a medical practitioner or any other person.

[0009] The present invention can be operated like a conventional syringe, wherein the retraction mechanism is automatically engaged as soon as the syringe is emptied. By providing a bendable flange on the plunger, the retraction mechanism is allowed to engage in one fluid movement, which is no different from the normal operation of a conventional syringe. Thus, the syringe according to the present invention does not give the operator any reason to doubt that the retraction has been properly and / or completely engaged, nor does it give the operator a reason to repeat the use of the syringe. Furthermore, as no volume adjustment of the barrel is required, the volume accuracy of the injection is optimally maintained.

[0010] The preferred embodiments of the device are shown in any one of claims 2 to 14.

[0011] The present invention also relates to a syringe set, preferably a pre-filled syringe set, with a needle retraction mechanism according to claim 15, which has the advantage that it can be used at any time, safely and intuitively for a medical practitioner or any other person.

[0012] The present invention can be operated like a conventional syringe, with the advantage that the retraction mechanism is automatically engaged as soon as the syringe is emptied. By providing a bendable flange on the plunger, the retraction mechanism is allowed to engage in one fluid movement, which is no different from the normal operation of a conventional syringe. Thus, the syringe set according to the present invention does not give the operator any reason to doubt that the retraction has been properly and / or completely engaged, nor does it give the operator a reason to reuse the syringe. Furthermore, the accuracy of the injected volume is optimally maintained, since no volume adjustment of the barrel is required. The syringe set consists of two components, i.e. the syringe assembly and the injection assembly, which has the additional advantage that the syringe set can be an assembly and disassembly kit configuration.

[0013] In some embodiments of the present invention, the syringe is a pre-filled syringe.

[0014] Preferred embodiments of the syringe set are shown in any of the dependent claims.

[0015] The present invention also relates to the use of a syringe set according to claim 27.

[0016] In a last aspect, the present invention relates to a method of manufacturing a syringe set according to claim 28. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1A A general view of a syringe according to an embodiment of the present invention is shown in its advanced position before engagement of the needle retraction mechanism.

[0018] Figure 1B A general view of a syringe according to an embodiment of the present invention is shown in its retracted position after engagement of the needle retraction mechanism.

[0019] Figure 2A A detailed view of the needle retraction mechanism of a syringe according to an embodiment of the present invention is shown before engagement of the mechanism.

[0020] Figure 2B A detailed view of the needle retraction mechanism of a syringe according to an embodiment of the present invention is shown during engagement of the mechanism.

[0021] Figure 2C A detailed view of the needle retraction mechanism of a syringe according to an embodiment of the present invention is shown during premature engagement of the mechanism.

[0022] Figure 3 A detailed view of the needle retraction mechanism of a syringe according to an embodiment of the present invention is shown, the needle retraction mechanism comprising a sealing ring fitted between the extractor element and the hollow plunger.

[0023] Figure 4 A detailed view of a needle retraction mechanism of a syringe according to an embodiment of the present invention is shown, including a sealing ring fitted between the extractor element and the hollow plunger, and a fitting for an interchangeable needle holder.

[0024] Figure 5 A general view of a syringe kit according to an embodiment of the present invention is shown in its advanced position before engagement of the needle retraction mechanism.

[0025] Figure 6 A general view of a syringe kit according to an embodiment of the present invention is shown in its retracted position after engagement of the needle retraction mechanism.

[0026] Figure 7 An embodiment of the present invention is shown, wherein the hollow nose end of the needle holder is further equipped with an internal annular ring.

[0027] Figure 8 An embodiment of the present invention is shown, wherein the extractor element is further equipped with a dead zone filler, and the inner surface of the plunger is equipped with an annular ring.

[0028] Figure 9 A plunger cap and retraction element equipped with a plurality of spring holding flaps are shown, the flaps shown respectively holding the proximal and distal ends of a restoring tension spring on the plunger cap and the extractor element.

[0029] Figure 10 A grommet between the outer surface of the needle holder and the inner surface of the hollow nose of the barrel body is shown. DETAILED DESCRIPTION

[0030] The present invention relates to a syringe with an improved needle retraction mechanism.

[0031] Unless otherwise defined, all terms used in disclosing the application, including technical and scientific terms, have the meaning commonly understood by one of ordinary skill in the art to which this application belongs. By further guidance, term definitions are included to better define the present teachings.

[0032] As used herein, the following terms have the following meanings:

[0033] As used herein, unless the context dictates the contrary, "a" and "the" refer to both the singular and the plural. For example, "compartment" refers to one or more compartments.

[0034] As used herein, "comprising" and "consisting of" are synonymous with "including" and "containing," and are inclusive or open-ended terms that specify the presence of stated elements, e.g., components, and do not exclude or preclude the presence or addition of additional, unrecited components, features, elements, steps known in the art or disclosed herein.

[0035] Furthermore, the terms first, second, third, etc. have been used, in the description and in the claims, to describe various elements, but the elements should not be limited to these descriptions as these can be other than the first and second, etc. unless otherwise specified. It will be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the application described herein are capable of operating in other sequences than described or illustrated herein.

[0036] The description of ranges of values should be considered inclusive of the values and fractions within the range, as well as the recited endpoints.

[0037] Although the term "one or more" or "at least one", for example one or more or at least one member of a group of members, is explicit by way of further illustration, this term includes, inter alia, a reference to any one of the members, or any two or more of the members (e.g., any >3, >4, >5, >6, or >7, etc. of the members), and up to all of the members.

[0038] A first aspect of the application relates to a syringe with an improved needle retraction mechanism, the syringe comprising:

[0039] a. a cylindrical barrel comprising a hollow main body and a hollow nose end;

[0040] b. a needle holder positioned in the nose end, wherein the needle holder comprises an internal cavity;

[0041] c. a hollow plunger positioned within the hollow main body of the cylindrical barrel;

[0042] d. a rod connected to or integral with the plunger and extending into the hollow main body of the cylindrical barrel, wherein each of the rod and the plunger has an axial bore therethrough;

[0043] e. an extractor element positioned within the axial bore of the plunger and within the bore of the rod;

[0044] f. a restoring tension spring or compression spring connected to the extractor element;

[0045] The extractor element is movable from an advanced position, in which it is surrounded by the plunger and a portion thereof protrudes beyond the distal end of the plunger or from the plunger in the direction of the needle holder, and a retracted position, in which it is fully retracted into the stem and positioned away from the needle holder; the extractor element has a male protrusion which protrudes beyond the distal end of the plunger or from the plunger in the advanced position to engage the internal cavity of the needle holder to couple the extractor element to the needle holder, and a hooking device which defines a connection between the plunger and the extractor element to keep the extractor element in the advanced position and the restoring spring in a stretched or compressed state; and wherein the axial bore of the plunger is defined by a plurality of bendable flanges configured to slide over the needle holder, the bendable flanges thereby bending outwards and expanding the axial bore of the plunger, and whereby the extractor element is decoupled from the plunger and retracted towards its retracted position.

[0046] In the context of the present invention, the term "syringe" relates to a simple reciprocating pump consisting of a "plunger" or "piston" which is tightly fitted within a cylindrical tube called "barrel". The plunger can be pulled and pushed along the internal line of the barrel, which allows the syringe to suck and expel a liquid through a discharge orifice located at the nose end of the barrel. According to the present invention, the nose end is fitted with a needle holder comprising a needle, such as a hypodermic needle. The syringes described herein are often used in clinical medicine to inject or infuse intravenous treatments into the blood.

[0047] The term "needle retraction mechanism" denotes any mechanism allowing the automatic retraction of the needle holder comprising the needle inside the syringe, in order to prevent the reuse of the syringe and / or to reduce the risk of needle stick injuries.

[0048] The terms "plunger" and "stem", in particular the expression "plunger connected to the stem", need to be interpreted as single and multiple pieces elements known in the art. In particular, the plunger and the stem can be provided as a single piece, while they can also comprise separate pieces which are connected to each other via usual connection means.

[0049] The term "extractor element" relates to a specific element of the retraction mechanism which extracts the needle and pulls it inside the syringe. According to the present invention, the actual retraction is achieved by a "restoring stretched or compressed spring", which indicates that the spring is in a stretched or compressed state during the operation of the syringe and is compressed or expanded to its rest state upon engagement of the retraction mechanism, thereby retracting the extractor element and the needle holder coupled thereto. In this case, the position before retraction is called "advanced position", while the position after retraction is called "retracted position".

[0050] The specific term "hooking means" relates to any means of reversibly interconnecting two or more elements to each other. Particular hooking means include complementary protrusions and / or recesses, areas of higher friction or adhesion, etc.

[0051] The term "bendable flange" herein relates to any bendable portion extending from the plunger in the direction of the needle holder, wherein its bendable nature is a result of e.g. a deformable material, a certain thickness provided to the flange, etc.

[0052] The syringe according to the present invention comprises a greatly improved needle retraction mechanism, which has the advantage that the syringe can be intuitively operated by a medical staff or any other person. The present invention can be operated like a conventional syringe, wherein the retraction mechanism is automatically engaged as soon as the syringe is emptied. Self-locking syringes known in the art usually require the operator to perform several and / or additional steps in order to engage the mechanism, i.e. the plunger has to be pushed further forward, the needle holder has to be coupled to the extractor element and the extractor element has to be decoupled from the plunger in a separate movement, etc. However, the present invention comprising a bendable flange on the plunger allows the retraction mechanism to be engaged in a fluid movement, which is not distinguishable from the normal operation of a conventional syringe. The substantially conical shape of the distal end of the male protrusion of the extractor element constitutes a steep angle, over which the bendable grip of the needle holder can slide, which requires only a small amount of bending of said bendable grip in order to engage said male protrusion. Furthermore, the entrance of the needle holder cavity formed by the bendable grip of the needle holder is characterized by a complementary conical recess to the distal end of the male protrusion. This way, the perceivable resistance felt by the user is advantageously kept to a minimum. The outer circumference of the bendable grip of the needle holder is further provided with a substantially angled surface, which advantageously permits a further reduction of the resistance perceived by the user when the bendable flange of the hollow plunger rides over said angled outer surface of the needle holder. The only haptic feedback provided to the user during operation of the syringe is the plunger reaching the end of the barrel and the impact of the extractor element on the retraction spring when the needle is retracted. Thus, the syringe according to the present invention does not give the operator any doubt whether the retraction has been correctly and / or completely engaged or not, nor does it give the operator the opportunity to reuse the syringe. As a result, any risk of needle stick injuries has been eliminated and reuse is effectively prevented. Furthermore, the accuracy of the injected volume is optimally maintained, since no volume adjustment of the barrel is required.

[0053] Preferably, the plurality of bendable flanges are bendable at an angle between 0° and -45° with respect to the axial centerline of the syringe. By allowing the bendable flanges to be bent at the above-mentioned angles, the extractor element can be separated from the plunger in one fluid motion. The bendable flanges are bent at an angle of, for example, -40° with respect to the axial centerline of the syringe, ensuring that the extractor element is locked inside the hollow plunger, wherein the restoring tension or compression spring is held in a tensioned or compressed state. Once the needle holder has substantially entered the axial cavity of the plunger, thereby opening the bendable flanges to an angle of, for example, -5° with respect to the axial centerline of the syringe, the extractor element is released from the plunger. This is why the restoring tension or compression spring is compressed or expanded, respectively, and pulls or pushes, respectively, the extractor element coupled to the needle holder inside the hollow plunger, thereby safely locking the needle inside the syringe.

[0054] More preferably, the plurality of bendable flanges are bendable at an angle between 0° and -40° with respect to the axial centerline of the syringe, even more preferably at an angle between 0° and -35°, between 5° and -35°, 5° and 30° or 10° and 30° with respect to the axial centerline of the syringe.

[0055] According to yet another or further embodiment, the plurality of bendable flanges comprises at least two bendable flanges. The presence of two bendable flanges allows the extractor element to remain in place within the hollow plunger. When the needle holder enters between the bendable flanges, the axial bore of the plunger expands uniformly and symmetrically, thereby allowing the extractor element and the needle holder coupled thereto to retract linearly within the syringe. Due to the configuration described herein, the needle retraction mechanism can be engaged by the operator, wherein only a slight resistance can be perceived. Therefore, operating the syringe according to the present application is not significantly different for the operator compared to operating a conventional syringe. As a result, operating the syringe according to the present application is particularly intuitive for a medical worker or any other person.

[0056] Preferably, the plurality of bendable flanges comprises at least three bendable flanges, more preferably at least four bendable flanges, at least five or at least six bendable flanges.

[0057] In some embodiments, the hooking means are complementary protrusions extending from both the hollow plunger and the extractor element. Such protrusions allow the extractor element to be smoothly separated from the hollow plunger by expanding the bendable flanges outwardly.

[0058] According to yet another or a further embodiment, said inner cavity of the needle holder is defined by a plurality of bendable grips configured to slide over the convex protrusion of the extractor element, said bendable grips thereby bending outwards and whereby the convex protrusion of the extractor element is inserted inside the inner cavity of the needle holder. The connection of the extractor element to the needle holder is particularly smooth, thus the handling of the syringe according to the present application does not differ significantly to the handling of a conventional syringe for the operator. At the same time, the provided bendable grips allow a secure and irreversible coupling of the extractor element to the needle holder. Thus, the needle retraction mechanism ensures an effective retraction of the needle holder including the needle inside the syringe.

[0059] Preferably, the plurality of bendable grips is configured to slide inside the axial bore of the plunger, said bendable grips thereby bending inwards and whereby the convex protrusion of the extractor element is locked inside the inner cavity of the needle holder. Moreover, the above-mentioned bending of the bendable grips towards the interior of the syringe upon engagement of the retraction mechanism ensures a secure coupling of the extractor element to the needle holder including the needle. Said coupling is particularly effective once the retraction is initiated and prevents an unintentional decoupling of the convex protrusion from the inner cavity of the needle holder.

[0060] According to yet another or a further embodiment, said plurality of bendable grips is bendable relative to the axial centerline of the syringe at an angle between -20° and 20°. The bending of the bendable grips relative to the axial centerline of the syringe at an angle of e.g. 15° ensures a smooth insertion of the convex protrusion of the extractor element inside the inner cavity of the needle holder. Once the needle holder is substantially inside the axial bore of the plunger, thereby opening the bendable flange, the flange pushes the bendable grips backwards, which are bent relative to the axial centerline of the syringe to an angle of e.g. -15°. This ensures an irreversible coupling of the convex protrusion, thereby preventing an unintentional decoupling of the convex protrusion from the inner cavity of the needle holder.

[0061] Preferably, said plurality of bendable grips is bendable relative to the axial centerline of the syringe at an angle between -15° and 15°, more preferably relative to the axial centerline of the syringe at an angle between -10° and 10°, -5° and 10° or -5° and 5°.

[0062] In some embodiments, the plurality of bendable gripping portions comprises at least two bendable gripping portions. The presence of two bendable gripping portions allows the inner cavity of the needle holder to expand uniformly and symmetrically, thereby allowing the convex protrusion to enter directly into the inner cavity of the needle holder. Furthermore, upon further retraction, the inner cavity of the needle holder narrows uniformly and symmetrically around the convex protrusion, thereby allowing the extractor element to be safely coupled to the needle holder. Due to the configuration described herein, the needle retraction mechanism can be engaged by the operator, wherein only a slight resistance can be perceived. Thus, compared to operating a conventional syringe, operating the syringe according to the present application does not feel significantly different to the operator. As a result, operating the syringe according to the present application is particularly intuitive to the medical worker or any other person.

[0063] Preferably, the plurality of bendable gripping portions comprises at least three bendable gripping portions, more preferably at least four bendable gripping portions, at least five bendable gripping portions, or at least six bendable gripping portions.

[0064] According to some embodiments, the needle holder is airtightly configured inside the hollow nose end, wherein the inner wall of the hollow nose end and the outer wall of the needle holder are of complementary, conical shape.

[0065] According to some embodiments, the syringe according to the present application comprises a gasket which is fitted around the plunger at its needle holder end, and wherein said gasket is fitted between the outer side of the plunger and the inner side of the hollow body of the cylindrical barrel, and wherein the gasket at least partially overlaps the plurality of bendable flanges.

[0066] In view of the present application, the term "gasket" relates to a mechanical seal which fills the space between two or more mating surfaces, which is often used to prevent leakage from or into a joined object when under compression. In the present case, the gasket is fitted between the outer side of the plunger and the inner side of the hollow body of the cylindrical barrel.

[0067] While the gasket serves primarily the purpose of making the syringe liquid- and airtight, the gasket additionally provides sufficient resistance against the expansion of the bendable flanges and / or the expansion of the bendable gripping portions. As a result, the single-stage coupling of the extractor element to the needle holder and the retraction of said two elements within the hollow plunger is further improved, as the gasket allows for just the right amount of expansion of the bendable flanges over the needle holder and / or the right amount of compression of the bendable gripping portions over the convex protrusion of the extractor element.

[0068] In some embodiments, the hollow body and the hollow nose end of the cylindrical barrel are provided as a single unit. These embodiments allow only for the assembly of the syringe with a single type of needle holder and / or needle. Among others, such syringes include pre-filled syringes, disposable syringes, etc. The described embodiments are particularly advantageous because the needle holder cannot be removed from the syringe at all without actually destroying the syringe.

[0069] In some embodiments, the hollow body and the hollow nose end of the cylindrical barrel are provided as two separate units, wherein the hollow body extends in a cylindrical or conical fitting comprising an axial bore adapted to at least partially receive the hollow nose end, in addition the fitting is further configured with connecting means for connecting the hollow nose end to the hollow body of the cylindrical barrel. The described embodiments allow the selection of a certain needle holder, in particular a certain needle, to be assembled in the hollow nose end of the syringe before using the syringe. By coupling the hollow nose end to the hollow body of the cylindrical barrel, the needle holder cannot be removed from the syringe once coupled, while the operator can select the needle before injection.

[0070] According to yet another or further embodiment, the extractor element is airtightly configured inside the hollow plunger by means of a sealing ring assembled between the inner wall of the plunger and the outer wall of the extractor element. Thus, the sealing ring assembled between the plunger and the extractor element ensures that no pressure is lost once the extractor element is coupled to the plunger. Once the syringe is completely emptied and the retraction mechanism is engaged, the sealing ring is no longer assembled between the two and thus the pressure is lost.

[0071] In some embodiments, the restoring spring is a restoring tensile spring, which is positioned inside the bore of the rod and connected to the extractor element. In this embodiment, the restoring tensile spring preferably extends along the length of the rod. Alternatively, in some embodiments, the restoring spring is a restoring compression spring. On one side of the needle holder, such restoring compression spring can be assembled between the extractor element and the hollow plunger.

[0072] According to some embodiments, the bendable flange is composed of a material having an elastic modulus between 600 and 2000 N / mm 2 , more preferably between 600 and 2500 N / mm 2 . Within the described range, the desired amount of bending is achieved, which allows for the smooth operation of the improved retraction mechanism according to the present invention. In this context, the term "elastic modulus" needs to be interpreted as: a measure of the ability of a material or a substance to resist elastic deformation (i.e. non-permanent) when a stress is applied to it. The elastic modulus of a material is defined as the slope of its stress-strain curve in the region of elastic deformation.

[0073] The flexible flange according to some embodiments of the present invention is made of a material having a strength of at least 15 N / mm. 2 More preferably at least 20 N / mm 2 The ultimate tensile strength, or tensile strength at break, is the material composition. This allows a bendable flange to withstand various stresses induced on the flange by the retraction mechanism without breaking. The terms "ultimate tensile strength" or "tensile strength at break" should be interpreted as the maximum stress a material can withstand when stretched or pulled before fracture. Ultimate tensile strength is typically determined by performing a tensile test and recording the stress-strain curve.

[0074] Preferably, the flexible flange is made of material having an elastic modulus between 600 and 2000, more preferably between 600 and 2500 N / mm. 2 Between and with at least 15 N / mm 2 More preferably at least 20 N / mm 2 The material composition has the ultimate tensile strength. Therefore, an optimal balance is found between the amount of bending and the ultimate tensile strength or the bendable flange, thus enabling the smooth release of the extractor element from the hollow plunger.

[0075] According to some embodiments, the flexible gripping part is made of materials with an elastic modulus of 600 and 2000 N / mm². 2 Between, and more preferably between, 600 and 2500 N / mm 2 The material composition is such that, within the specified range, the desired amount of bending of the flexible gripper of the needle holder is achieved, which allows for smooth operation of the improved retraction mechanism according to the invention.

[0076] The flexible gripping part according to some embodiments of the present invention is made of a material having a strength of at least 15 N / mm². 2 More preferably at least 20 N / mm 2 It is made of a material with ultimate tensile strength or tensile strength at break. Therefore, the flexible grip can withstand various stresses caused by the retraction mechanism on the grip without breaking.

[0077] Preferably, the flexible gripping part is made of materials with an elastic modulus between 600 and 2000 N / mm². 2 More preferably between 600 and 2500 N / mm 2 Between, and having an ultimate tensile strength of at least 15 N / mm. 2 More preferably at least 20 N / mm 2 The material composition is such that an optimal balance is achieved between the amount of bending and the ultimate tensile strength or the flexible grip, thus enabling a smooth connection between the convex protrusion of the extractor element and the needle holder.

[0078] In some embodiments, the extractor element is airtightly configured inside the hollow plunger, wherein the inner wall of the hollow plunger and the outer wall of the extractor element are of complementary, conical shape.

[0079] In some embodiments of the application, the syringe is a pre-filled syringe.

[0080] In another aspect, the application relates to a syringe kit, preferably a pre-filled syringe kit, comprising a syringe assembly and an injection assembly, the syringe assembly comprising:

[0081] a. a cylindrical barrel comprising a hollow body, wherein the hollow body is at least partially filled with an injectable liquid;

[0082] b. a hollow plunger positioned within the hollow body of the cylindrical barrel;

[0083] c. a stem connected to or integral with the plunger and extending into the hollow body of the cylindrical barrel, wherein the stem and the plunger each have an axial bore therethrough;

[0084] d. an extractor element positioned within the axial bore of the plunger and the bore of the stem;

[0085] e. a restoring tension spring or a restoring compression spring connected to the extractor element; and

[0086] the injection assembly comprising:

[0087] a. a hollow nose end; and

[0088] b. a needle holder positioned in the nose end, wherein the needle holder comprises an internal cavity; wherein:

[0089] - the syringe assembly and the injection assembly comprise a first connection portion and a second connection portion, respectively, configured to achieve a closed kit configuration and an open kit configuration, the closed kit configuration comprising an airtight connection of the syringe assembly with the injection assembly, wherein the internal cavity of the needle holder and the hollow body of the cylindrical barrel are configured to form a continuous passage allowing the passage of the injectable liquid, and the open kit configuration comprising an airtight seal of the syringe assembly without the injection assembly being connected;

[0090] - the extractor element is movably from an advanced position, in which it is surrounded by the plunger and a portion protrudes beyond the distal end of the plunger or from the plunger in the direction of the first connection portion, and a retracted position, in which it is fully retracted into the stem and positioned away from the first connection portion;

[0091] - the extractor element has a convex protrusion protruding beyond the distal end of the plunger or protruding from the plunger in the advanced position to engage the inner cavity of the needle holder to couple the extractor unit to the needle holder, and a hooking means defining a connection between the plunger and the extractor element to hold the extractor element in the advanced position and to hold the restoring spring in a stretched or compressed state;

[0092] wherein the axial bore of the plunger is defined by a plurality of bendable flanges configured to slide over the needle holder, the bendable flanges thereby bending outwards and expanding the axial bore of the plunger, and whereby the extractor element is disconnected from the plunger and retracted towards its retracted position.

[0093] In the context of the present invention, the specific terms "injector assembly" and "injection assembly" relate to two different parts of the "injector kit" as described herein. Since the kit of the present invention can be an assembly and disassembly kit configuration, the injector kit in its assembled configuration and / or in its working state is referred to as "injector" for ease of reference.

[0094] The injector kit according to the present invention comprises a greatly improved needle retraction mechanism, which has the advantage that the injector kit can be used at any time, safely and intuitively operable for a medical worker or any other person. The present invention can be operated like a conventional injector, wherein the retraction mechanism is automatically engaged as soon as the injector is emptied.

[0095] In some embodiments, the first and second connection parts of the respective injector assembly and injection assembly are hermetically connected to each other. This particular embodiment relates to the assembled kit configuration and can be manufactured and / or supplied as such. In particular, the injector manufacturer can manufacture the injector assembly and the injection assembly, thereby filling the hollow body of the barrel with the injectable liquid and hermetically connecting the injector assembly to the injection assembly, thereby locking the injectable liquid within the closed injector kit. The injector kit described herein is particularly advantageous in case a certain injectable liquid is used with a certain needle, and the injector kit is ready for use. In this respect, the kit is already provided with a sufficient needle and does not leave the user in doubt about the choice of needle nor about how the kit should be operated.

[0096] In some embodiments, the respective syringe assembly and the first and second connection portions of the injection assembly are disconnected from each other, wherein the hollow body of the barrel is hermetically sealed by the closure cap fitted to the first connector portion of the syringe assembly. This particular embodiment relates to a detachable kit configuration and can be manufactured and / or supplied as such. In particular, a syringe manufacturer can manufacture a syringe assembly and a plurality of injection assemblies, fill the hollow body of the barrel with an injectable liquid and hermetically seal the hollow body of the barrel by the closure cap. The syringe kit as described herein is particularly advantageous in case a certain injectable liquid is used, but the needle selection is not yet fixed. This provides additional freedom of choice for the manufacturer and the end user, as the needle selection does not need to be decided immediately yet. In particular, the syringe kit can be provided as a syringe assembly and a single injection assembly, wherein the user needs to remove the closure cap and connect the two assemblies to each other before use. The needle selection will then be delayed until the user purchases a needle kit from the manufacturer. Alternatively, the syringe kit can be provided as a syringe assembly and a plurality of different injection assemblies, wherein the user can select an injection assembly before use, i.e. by connecting the syringe assembly and the selected injection assembly to each other.

[0097] The advantages of a syringe kit with separate syringe assembly and injection assembly relate to a broad range of packaging options, which also improves the ease of use for the user. While the syringe kit can be packaged as one unit, the syringe assembly and the injection assembly can also be packaged separately. In this regard, packaging a plurality of syringe assemblies and / or injection assemblies into so-called "nesting" is considered a safe packaging method.

[0098] In an embodiment, the syringe kit as described herein provides a syringe with a needle retraction mechanism as described in one of the above embodiments and is considered a repetition in the context of a kit.

[0099] The present invention also relates to the use of a (prefilled) syringe kit for injecting an injectable liquid in a subject, wherein the syringe assembly and the injection assembly are connected to each other prior to the injection.

[0100] A last aspect of the present invention relates to a method of manufacturing a syringe kit, preferably a prefilled syringe kit, the method comprising:

[0101] - assembling or providing a syringe assembly comprising:

[0102] a. a cylindrical barrel comprising a hollow body;

[0103] b. a hollow plunger positioned within the hollow body of the cylindrical barrel;

[0104] c. a rod connected to or integral with the plunger and extending into the hollow body of the cylindrical barrel, wherein the rod and the plunger each have an axial bore therethrough;

[0105] d. an extractor element positioned within the axial bore of the plunger and the bore of the rod; and e. a restoring tension spring or a restoring compression spring connected to the extractor element;

[0106] - assembling or providing a needle assembly comprising the following parts:

[0107] a. a hollow nose end; and

[0108] b. a needle holder positioned in the nose end, wherein the needle holder comprises an inner cavity; wherein

[0109] the syringe assembly and the injection assembly comprise a first connection part and a second connection part, respectively, the first connection part allowing a gas-tight sealing of the hollow body of the barrel and allowing a gas-tight connection with the second connection part of the injection assembly, wherein the inner cavity of the needle holder and the hollow body of the cylindrical barrel are configured to form a continuous passage allowing a passable injectable liquid,

[0110] the extractor element is moveable from an advanced position, in which the extractor element is surrounded by the plunger and a portion protrudes beyond the distal end of the plunger or from the plunger in the direction of the first connection part, and a retracted position, in which the extractor element is fully retracted into the rod and positioned away from the first connection part;

[0111] the extractor element has a male protrusion protruding beyond the distal end of the plunger or from the plunger in the advanced position to engage the inner cavity of the needle holder to couple the extractor element to the needle holder, and a hooking means defining a connection between the plunger and the extractor element to hold the extractor element in the advanced position and the restoring spring in a stretched or compressed state; and wherein

[0112] the axial bore of the plunger is defined by a plurality of bendable flanges configured to slide over the needle holder, the bendable flanges thereby bending outwards and expanding the axial bore of the plunger, and whereby the extractor element is decoupled from the plunger and retracted towards its retracted position;

[0113] - at least partially filling the hollow body of the cylindrical barrel with an injectable liquid; and

[0114] - gas-tightly closing the hollow body of the cylindrical barrel.

[0115] Preferably, the method manufactures a syringe set according to one of the above-mentioned embodiments.

[0116] In a preferred embodiment of the application, the syringe set is a pre-filled syringe set.

[0117] In particular, the filling and hermetic closure steps can be performed by using a plurality of syringe assemblies and / or a specific nested configuration of the syringe assemblies. So-called "nested" configurations are particularly suitable for safely transporting sterile syringe assemblies from, for example, a syringe manufacturing site to a syringe filling site. The nested configuration comprises placing a plurality of syringe assemblies in a packaging tray and sealing the tray with a sheet (e.g. a Tyvek sheet). Thereafter, the packaging and its content can be sterilized. At the time of filling, the sheet is removed and the syringe assemblies enter the filling line. The nested configuration as described herein can be an upside-down configuration, or a downside-up configuration. The so-called upside-down configuration provides for filling the syringe assemblies with the injectable liquid from an opening on the top of the barrel. Thus, the syringe assemblies can be closed with a closure cap or with a syringe assembly. The so-called downside-up configuration allows filling the syringe assemblies from the lower part of the barrel and then closing by inserting a plunger therein.

[0118] Description of the drawings

[0119] The application is further described by the following drawings, which illustrate the application and are not intended to, nor should be interpreted to, limit the scope of the application.

[0120] Figure 1A and Figure 1BA general view of a syringe according to an embodiment of the present application is shown. Therein, the shown syringe has an improved needle retraction mechanism and comprises a cylindrical barrel 1 comprising a hollow main body 2 and a hollow nose end 3. The syringe further comprises a needle holder 4 positioned in the nose end 3, the needle holder 4 comprising an inner cavity 5. A hollow plunger 6 is positioned within the hollow main body 2 of the cylindrical barrel 1, the hollow plunger 6 being connected to a stem 7, the stem extending into the hollow main body 2 of the cylindrical barrel 1 and wherein both the stem and the plunger have an axial bore therethrough. The syringe comprises an extractor element 8 positioned within the axial bore of the plunger 6 and within the bore of the stem 7, a restoring tension spring 9 positioned within the bore of the stem 7 and connected to the extractor element 8, the extractor element 8 being moveable from an advanced position, in which the extractor element is surrounded by the plunger 6 and a portion thereof protrudes from the plunger 6 in the direction of the needle holder 4, and a retracted position, in which the extractor element is fully retracted into the stem 7 and positioned away from the needle holder 4, the extractor element 8 having a male protrusion 10 protruding from the plunger 6 in the advanced position to engage the inner cavity 5 of the needle holder to couple the extractor 8 element to the needle holder 5, and a hooking means 11 defining a connection between the plunger 6 and the extractor element 8 to hold the extractor element 8 in the advanced position and to hold the restoring spring 9 in a tensioned state. The axial bore of the plunger 6 is defined by a plurality of bendable flanges 12 configured to slide over the needle holder 5, the bendable flanges thereby bending outwards and expanding the axial bore of the plunger 6 and thereby decoupling the extractor element 8 from the plunger 6 and retracting towards its retracted position. Figure 1A and Figure 1BThe syringe is shown in its advanced position and in its retracted position, respectively. The syringe shown herein is advantageous in that the syringe is intuitively operable for a medical care worker or any other person. The invention can be operated like a conventional syringe, wherein the retraction mechanism is automatically engaged as soon as the syringe is emptied. In particular, the bendable flange 12 allows the retraction mechanism to engage in a fluid motion, which is no different from the normal operation of a conventional syringe. Furthermore, the volume accuracy of the injection is optimally maintained, since no volume adjustment of the barrel 1 is required. The bendable flange 12 as shown herein can be bent in particular at an angle between 0° and -45° with respect to the axial center line of the syringe. The syringe shown herein comprises a gasket 14, which is fitted around the plunger 6 at the end of its needle holder 4, and wherein said gasket 14 is fitted between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1, and wherein the gasket 14 at least partially overlaps with the plurality of bendable flanges 12. In the embodiment shown, the hollow body 2 and the hollow nose end 3 of the cylindrical barrel 1 are provided as a single unit. The extractor element 8 is airtightly configured inside the hollow plunger 6 by means of a conical fitting 17 between the inner wall of the plunger 6 and the outer wall of the extractor element 8.

[0121] Figure 2A 、 Figure 2B and Figure 2C a detailed view of the needle retraction mechanism of the syringe according to an embodiment of the invention is shown, which is advanced by engagement of the retraction mechanism. In particular, Figures 2A-2CA barrel 1 comprising a hollow body 2, a hollow nose end 3, a needle holder 4, an inner cavity 5 of the needle holder 4, a hollow plunger 6, a rod 7, an extractor element 8, a restoring tension spring 9, a male protrusion 10 of the extractor element 8, a hooking device 11 between the plunger 6 and the extractor element 8, and a bendable flange 12 of the hollow plunger 6 are shown. Furthermore, the inner cavity 5 of the needle holder 4 is defined by a plurality of bendable gripping portions 13 configured to slide over the male protrusion 10 of the extractor element 8, said bendable gripping portions 13 thereby bending outwards and by which the male protrusion 10 of the extractor element 8 is inserted inside the inner cavity 5 of the needle holder 4. The connection of the extractor element 8 to the needle holder 4 is particularly smooth, thus the operation of the injector according to the present invention does not feel significantly different to the operator compared to the operation of a conventional injector. At the same time, the provided bendable gripping portions 13 allow a secure and irreversible connection of the extractor element 8 to the needle holder 4. Furthermore, the plurality of bendable gripping portions 13 are configured to slide within the axial bore of the plunger 6, said bendable gripping portions 13 thereby bending inwards and by which the male protrusion 10 of the extractor element 8 is locked inside the inner cavity 5 of the needle holder 4. Furthermore, the bending of said bendable gripping portions 13 towards the inside of the injector upon engaging the retraction mechanism ensures a secure connection of the extractor element 8 to the needle holder 4 comprising the needle 21. The bendable gripping portions 13 shown herein can be bent in particular with an angle between -20° and 20° with respect to the axial center line of the injector. Furthermore, the injector shown herein comprises a gasket 14 which is fitted around the plunger 6 at its end of the needle holder 4 and wherein said gasket 14 is fitted between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1 and wherein the gasket 14 at least partially overlaps with the plurality of bendable flanges 12. In the shown embodiment, the hollow body 2 and the hollow nose end 3 of the cylindrical barrel 1 are provided as a single unit. The extractor element 8 is airtightly configured within the hollow plunger 6 by means of a conical fitting 17 located between the inner wall of the plunger 6 and the outer wall of the extractor element 8. In particular, Figure 2A A retraction mechanism before engagement is shown, Figure 2B A male protrusion 10 sliding into the inner cavity 5 of the needle holder 4 is shown, thereby coupling the extractor element 8 to the needle holder 4. Figure 2C The advancement of the retraction mechanism is also shown, as the bendable flange 12 of the hollow plunger 6 expands, thus releasing the extractor element 8 from the hollow plunger 6, at the same time, tightening the connection between the male protrusion 10 and the needle holder 4 by bending the gripping portions 13 inwards.

[0122] Figure 3A detailed view of a needle retraction mechanism present in a empty syringe according to an embodiment of the present application is shown. The following is shown: a barrel 1 comprising a hollow body 2, a hollow nose end 3, a needle holder 4, an inner cavity 5 of the needle holder 4, a hollow plunger 6, a rod 7, an extractor element 8, a restoring tension spring 9, a convex protrusion 10 of the extractor element 8, a hooking device 11 between the plunger 6 and the extractor element 8, and a bendable flange 12 of the hollow plunger 6. Furthermore, the inner cavity 5 of the needle holder 4 is defined by a plurality of bendable grips 13 configured to slide over the convex protrusion 10 of the extractor element 8, which bendable grips 13 thereby bend outwardly and whereby the convex protrusion 10 of the extractor element 8 is inserted into the inner cavity 5 of the needle holder 4. The connection of the extractor element 8 to the needle holder 4 is particularly smooth, thus, the operation of the (pre-filled) syringe kit according to the present application does not feel significantly different to the operator compared to the operation of a conventional syringe. At the same time, the provided bendable grips 13 allow a secure and irreversible connection of the extractor element 8 to the needle holder 4. Furthermore, the plurality of bendable grips 13 is configured to slide within an axial bore of the plunger 6, which bendable grips 13 thereby bend inwardly and whereby the convex protrusion 10 of the extractor element 8 is locked inside the inner cavity 5 of the needle holder 4. Furthermore, the bending of the bendable grips 13 towards the interior of the syringe upon engagement of the retraction mechanism ensures a secure connection of the extractor element 8 to the needle holder 4 comprising the needle 21. The bendable grips 13 shown herein can especially be bent with an angle between -20° and 20° with respect to the axial center line of the syringe. Furthermore, the (pre-filled) syringe kit shown herein comprises a grommet 14 which is fitted around the plunger 6 at the end of its needle holder 4, and wherein the grommet 14 is fitted between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1, and wherein the grommet 14 at least partially overlaps with the plurality of bendable flanges 12. In the shown embodiment, the hollow body 2 and the hollow nose end 3 of the cylindrical barrel 1 are provided as a single unit. The extractor element 8 is hermetically configured within the hollow plunger 6 by means of a conical fitting 17 between the inner wall of the plunger 6 and the outer wall of the extractor element 8.

[0123] Figure 4A detailed view of a needle retraction mechanism of a syringe according to an embodiment of the present application is shown, which comprises a cylindrical or conical fitting 15 for an interchangeable needle holder. The hollow body 3 and the hollow nose end 2 of the cylindrical barrel are provided as two separate units, wherein the hollow body 2 extends in a fitting 15 comprising an axial bore. Said axial bore of the fitting 15 is adapted to at least partially receive the hollow nose end 3, and in addition, the fitting 15 is configured with a first connecting portion 19 for connecting a complementary second connecting portion 20 integral with the hollow nose end 3 and permitting the connection of said hollow nose end 3 to the hollow body 2 of the cylindrical barrel 1. These provisions allow the selection of a certain needle holder 4, in particular a certain needle 21, to be fitted in the hollow nose end 3 of the syringe.

[0124] Figure 5 and Figure 6 A general view of a (prefilled) syringe kit according to an embodiment of the present application is shown.

[0125] Wherein the syringe kit has an improved needle retraction mechanism for ease and safety of use (as described in the preceding figures). The syringe kit comprises a syringe assembly S and an injection assembly I. The latter comprises a hollow nose end 3 and a needle holder 4 positioned therein. Said needle holder 4 comprises an inner cavity 5. The syringe assembly S comprises a barrel 1 having a hollow body 2 comprising an injectable liquid L and further comprising a hollow plunger 6 positioned within the hollow body 2 of the cylindrical barrel 1, said hollow plunger being connected to a stem 7 extending into the hollow body 2 of the cylindrical barrel 1 and wherein both the stem and the plunger have an axial bore therethrough. The syringe assembly S comprises an extractor element 8 positioned within the axial bore of the plunger 6 and the bore of the stem 7, a restoring tension spring 9 positioned within the bore of the stem 7 and connected to the extractor element 8, said extractor element 8 being moveable from an advanced position, in which it is surrounded by the plunger 6 and a portion thereof protrudes from the plunger 6 in the direction of the needle holder 4, and a retracted position, in which it is fully retracted into the stem 7 and positioned away from the needle holder 4, said extractor element 8 having a male protrusion 10 protruding from the plunger 6 in the advanced position to engage the inner cavity of the needle holder 5 to couple the extractor element 8 to the needle holder 5, and a hooking means 11 defining a coupling between the plunger 6 and the extractor element 8 to retain the extractor element 8 in the advanced position and the restoring spring 9 in a tensioned state. The axial bore of the plunger 6 is defined by a plurality of bendable flanges 12 configured to slide over the needle holder 4, said bendable flanges thereby bending outwards and expanding the axial bore of the plunger 6 and thereby decoupling the extractor element 8 from the plunger 6 and retracting it towards its retracted position. Figure 5 and Figure 6An injection set is shown in its advanced position and in its retracted position, respectively. The injection set shown herein has the advantage that it is intuitively operable for a medical worker or any other person and is ready for use at any time. The invention can be operated like a regular injection set, wherein the retraction mechanism is automatically engaged as soon as the injection set is emptied. In particular, the bendable flange 12 allows the retraction mechanism to engage in a fluid motion, which is no different from the normal operation of a regular injection set. Furthermore, the volume accuracy of the injection is optimally maintained, since no volume adjustment of the barrel 1 is required. The bendable flange 12 as shown herein can be bent in particular at an angle between 0° and -45° with respect to the axial center line of the injection set. The injection set shown herein comprises a gasket 14, which is fitted around the plunger 6 at the end of its needle holder 4, and wherein said gasket 14 is fitted between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1, and wherein the gasket 14 at least partially overlaps with the plurality of bendable flanges 12. The injection assembly S and the injection assembly I comprise a first connection portion 19 and a second connection portion 20, respectively, which are configured to enable a closed set configuration and an open set configuration, the closed set configuration comprising a gas-tight connection of the injection assembly S with the injection assembly I, wherein the inner cavity 5 of the needle holder 4 and the hollow body 2 of the cylindrical barrel 1 are configured to form a continuous passage allowing the injectable liquid L to pass through. Furthermore, it is shown that the injection assembly I comprises a needle 21 and a needle cap 18.

[0126] Figure 7 In the middle it is shown a specific embodiment according to the current invention, wherein the inner surface of the cylindrical barrel 3 is provided with an annular ring 23, which is configured to contact and support the outer circumference of the needle holder 4.

[0127] Figure 8 In the middle it is shown another specific embodiment according to the current invention, wherein the extractor element 8 is provided with a dead zone filling 22 extending from the distal end of the extractor element 8. The distal end of said dead zone filling 22 provides a base from which the male protrusion of the extractor element 10 is protruding at this moment. In this figure it is shown the inner surface of the hollow plunger 6 provided with an annular ring 24, which is configured to provide a contact surface between the extractor element 8 and the inner surface of the hollow plunger 6.

[0128] Figure 9A plunger cap 25 and an extractor element 8 attached to the restoring tension spring 9 are exemplified, which are also equipped with a plurality of radially extending elastic retaining springs 26. In the figure, the proximal end of the restoring tension spring 9 is shown, the first two coils of which surround the plunger cap 25, which two coils are held by a plurality of spring retaining tabs 26. Also in the figure, the distal end of the same restoring tension spring 9 is shown, the two last coils of which surround the proximal end of the extractor element 8, and which two coils are also held by a plurality of spring retaining tabs 26.

[0129] Figure 10 Another embodiment is also exemplified, in which a substantially cylindrical needle holder 4 is shown in airtight connection with the hollow nose end 3 of the cylindrical barrel. The airtight connection is provided by a gasket 27, which is arranged between the circumference of the needle holder 4 and the conical surface within the hollow nose end 3 of the cylindrical barrel.

[0130] List of reference item

[0131] S syringe assembly

[0132] I injection assembly

[0133] L injectable liquid

[0134] 1 cylindrical barrel

[0135] 2 hollow body of the cylindrical barrel

[0136] 3 hollow nose end of the cylindrical barrel

[0137] 4 needle holder

[0138] 5 inner cavity of the needle holder

[0139] 6 hollow plunger

[0140] 7 rod

[0141] 8 extractor element

[0142] 9 restoring tension spring

[0143] 10 convex protrusion of the extractor element

[0144] 11 hooking means between the plunger and the extractor element

[0145] 12 bendable flange of the hollow plunger

[0146] 13 bendable grip of the needle holder

[0147] 14 gasket

[0148] 15 fitting of the barrel

[0149] 16 sealing ring

[0150] 17 tapered fitting

[0151] 18 needle cap

[0152] 19 first connecting portion

[0153] 20 second connecting portion

[0154] 21 needle

[0155] 22 dead space filler

[0156] 23 hollow nose annular ring

[0157] 24 plunger annular ring

[0158] 25 plunger cap

[0159] 26 spring retention tab

[0160] 27 needle retainer washer

Claims

1. A syringe with an improved needle retraction mechanism, the syringe comprising: a. A cylindrical body (1), the cylindrical body comprising a hollow main body (2) and a hollow nose end (3); b. Needle retainer (4), the needle retainer being positioned in the nasal tip, wherein the needle retainer includes an inner cavity (5). c. Hollow plunger (6), wherein the hollow plunger is positioned inside the hollow body of the cylindrical tube; d. Rod (7), the rod being connected to or integral with the plunger and extending into the hollow body of the cylindrical body, wherein both the rod and the plunger have an axial hole therethrough; e. Extractor element (8), the extractor element being positioned within the axial bore of the plunger and the axial bore of the rod; f. A restoring tension or compression spring (9), which is connected to the extractor element; The extractor element is movable from a forward position (A) and a retracted position (B). In the forward position, the extractor element is surrounded by the plunger and partially protrudes in the direction of the needle holder. In the retracted position, the extractor element is fully retracted into the rod and positioned away from the hollow nose (3). The extractor element has a convex protrusion (10) and a hook device (11), the convex protrusion projecting in the forward position to engage the inner cavity of the needle holder to attach the extractor element to the needle holder, the hook device defining the connection between the plunger and the extractor element to hold the extractor element in the forward position and to hold the restoring tension or compression spring in a tension or compression state; The plunger is characterized in that the axial bore of the plunger is defined by at least two flexible flanges (12) configured to slide over the needle holder, the flexible flanges thereby bending outward and expanding the axial bore of the plunger, and thereby the extractor element is disconnected from the plunger and retracts toward its retracted position.

2. The syringe according to claim 1, characterized in that, The at least two flexible flanges (12) are capable of bending relative to the axial centerline of the syringe at an angle between 0° and -45°.

3. The syringe according to claim 2, characterized in that, The at least two flexible flanges (12) include at least three flexible flanges.

4. The syringe according to claim 1 or 2, characterized in that, The hook device (11) is a complementary protrusion extending from the hollow plunger (6) and the extractor element (8).

5. The syringe according to claim 1 or 2, characterized in that, The inner cavity (5) of the needle holder (4) is defined by a plurality of flexible grips (13) configured to slide over the protrusion (10) of the extractor element (8), the flexible grips thus bending outward, and thereby the protrusion of the extractor element inserting into the inner cavity of the needle holder.

6. The syringe according to claim 5, wherein, The plurality of flexible grips (13) are configured to slide inside the axial bore of the plunger (6), thereby bending inward and thus locking the convex protrusion (10) of the extractor element (8) inside the cavity (5) of the needle holder (4).

7. The syringe according to claim 5, characterized in that, The plurality of flexible grips (13) can be bent relative to the axial centerline of the syringe at an angle between -20° and 20°.

8. The syringe according to claim 5, characterized in that, The plurality of flexible grips (13) includes at least two flexible grips.

9. The syringe according to claim 5, characterized in that, The plurality of flexible grips (13) includes at least three flexible grips.

10. The syringe according to claim 1 or 2, characterized in that, The needle holder (4) is hermetically disposed inside the hollow nose (3), wherein the inner wall of the hollow nose and the outer wall of the needle holder are complementary conical shapes.

11. The syringe according to claim 1 or 2, wherein, The syringe also includes a washer (14) which is fitted around the plunger (6) at the needle holder end of the plunger and wherein the washer is fitted between the outside of the plunger and the inside of the hollow body (2) of the cylindrical body (1), and the washer at least partially overlaps the at least two flexible flanges (12).

12. The syringe according to claim 1 or 2, characterized in that, The hollow body (2) and the hollow nose (3) of the cylindrical tube (1) are configured as a single unit.

13. The syringe according to claim 1 or 2, characterized in that, The hollow body (2) and the hollow nose (3) of the cylindrical body (1) are configured as two independent units, wherein the hollow body extends in a fitting (15) including an axial hole adapted to receive the hollow nose at least partially, and the fitting is also configured with a connecting device for connecting the hollow nose to the hollow body of the cylindrical body.

14. The syringe according to claim 1 or 2, characterized in that, The extractor element (8) is hermetically disposed inside the hollow plunger (6) by a sealing ring (16) fitted between the inner wall of the plunger and the outer wall of the extractor element.

15. The syringe according to claim 1 or 2, characterized in that, The extractor element (8) is hermetically disposed inside the hollow plunger (6), wherein the inner wall of the hollow plunger and the outer wall of the extractor element are complementary conical shapes.

16. A syringe kit, the syringe kit comprising a syringe assembly (S) and an injection assembly (I), the syringe assembly comprising: a. A cylindrical body (1), the cylindrical body comprising a hollow body (2), wherein the hollow body is at least partially filled with an injectable liquid (L); b. Hollow plunger (6), wherein the hollow plunger is positioned inside the hollow body of the cylindrical tube; c. Rod (7), the rod extending at least partially into the hollow body of the cylindrical tube, wherein both the rod and the plunger have an axial hole therethrough; d. Extractor element (8), the extractor element being positioned within the axial bore of the plunger and the axial bore of the rod; e. A restoring tension or compression spring (9), said restoring tension or compression spring being connected to the extractor element; and The injection assembly includes: a. Hollow nasal tip (3); and b. A needle retainer (4), wherein the needle retainer is positioned in the nasal tip, and wherein the needle retainer includes an inner cavity (5); wherein - The syringe assembly and the injection assembly each include a first connecting portion (19) and a second connecting portion (20), the first connecting portion and the second connecting portion being configured to implement a closed kit configuration and an open kit configuration, the closed kit configuration including an airtight connection between the syringe assembly and the injection assembly, wherein the inner cavity of the needle holder and the hollow body of the cylindrical tube are configured to form a continuous channel allowing the injectable liquid to pass through, and the open kit configuration including an airtight seal of the syringe assembly when the injection assembly is not connected; - The extractor element is movable from a forward position (A) and a retracted position (B). In the forward position, the extractor element is surrounded by the plunger and a portion protrudes in the direction of the first connecting portion. In the retracted position, the extractor element is fully retracted into the rod and positioned away from the first connecting portion. - The extractor element has a convex protrusion (10) and a hook device (11), the convex protrusion projecting in the forward position to engage the inner cavity of the needle holder to engage the extractor element to the needle holder, the hook device defining the connection between the plunger and the extractor element to hold the extractor element in the forward position and to hold the restoring tension or compression spring in a tension or compression state; The plunger is characterized in that the axial bore of the plunger is defined by a plurality of flexible flanges (12) configured to slide over the needle holder, the flexible flanges thereby bending outward and expanding the axial bore of the plunger, and thereby the extractor element is disconnected from the plunger and retracts toward its retracted position.

17. A method of manufacturing a syringe kit, the method comprising: - Assemble or supply syringe components including the following parts: a. A cylindrical body (1), wherein the cylindrical body includes a hollow main body (2); b. Hollow plunger (6), wherein the hollow plunger is positioned inside the hollow body of the cylindrical tube; c. Rod (7), the rod extending at least partially into the hollow body of the cylindrical tube, wherein both the rod and the plunger have an axial hole therethrough; d. Extractor element (8), the extractor element being positioned within the axial bore of the plunger and the axial bore of the rod; and e. A restoring tension or compression spring (9), which is connected to the extractor element; - Assemble or supply injection components including the following parts: a. Hollow nasal tip (3); and b. A needle retainer (4), wherein the needle retainer is positioned in the nasal tip, and the needle retainer includes an inner cavity (5); wherein: The syringe assembly and the injection assembly each include a first connecting portion (19) and a second connecting portion (20). The first connecting portion allows for an airtight seal of the hollow body of the cylindrical body and allows for an airtight connection with the second connecting portion of the injection assembly. The inner cavity of the needle holder and the hollow body of the cylindrical body are configured to form a continuous channel allowing injectable liquid to pass through. The extractor element is movable from a forward position (A) and a retracted position (B). In the forward position, the extractor element is surrounded by the plunger and a portion protrudes in the direction of the first connecting portion. In the retracted position, the extractor element is fully retracted into the rod and positioned away from the first connecting portion. The extractor element has a convex protrusion (10) and a hook device (11), the convex protrusion projecting in the forward position to engage the inner cavity of the needle holder to attach the extractor element to the needle holder, the hook device defining the connection between the plunger and the extractor element to hold the extractor element in the forward position and to hold the restoring tension or compression spring in a tensioned or compressed state; and wherein The axial bore of the plunger is defined by a plurality of flexible flanges (12) configured to slide over the needle holder, the flexible flanges thereby bending outward and expanding the axial bore of the plunger, and thereby the extractor element disconnects from the plunger and retracts toward its retracted position. - The hollow body of the cylindrical tube is at least partially filled with an injectable liquid; - The hollow body of the cylindrical tube is airtightly sealed.

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