Syringe surrogate and method of testing an autoinjector

Abstract

A syringe surrogate (102) is configured to mimic a syringe in an autoinjector when the autoinjector is tested. The syringe surrogate (102) comprises a longitudinal axis, a body portion (202), a flange portion (402) and a needle portion (302). The body portion (202) has a hollow interior, an open distal end and a proximal end (2202). The flange portion (402) is located at or near the distal end of the body portion (202). The body portion (202) extends along the longitudinal axis (502). The needle portion (302) axially projects from the proximal end (2202) of the body portion (202). The flange portion (402) is circumferentially arranged around the body portion (202). The body portion (202) and the needle portion (302) are made of a deformable material.

Description

DESCRI PTIONTitleSYRINGE SURROGATE AND METHOD OF TESTING AN AUTOINJECTORTechnical Field

[0001] The present invention relates to a syringe surrogate to mimic a syringe in an autoinjector when the autoinjector is tested and, more particularly, to a method of testing an autoinjector.Background Art

[0002] For administering liquid drug substances, often conventional syringes are used. In particular, the syringes may be prefilled with the drug substance of may be filled with the drug substance prior use. Thereby, a liquid drug substance can be, e.g. subcutaneously or intramuscularly, injected into a patient.

[0003] For increasing safety and convenience in application, it is known to use autoinjectors which (semi-)automatically inject the drug substance. Typically, a syringe containing the liquid drug substance is set into the autoinjector, the autoinjector is then positioned at an appropriate location of a body of the patient and a button is pushed or another mechanism is triggered to activate the autoinjector. Then either the autoinjector forwards the needle of the syringe into the body to a predefined piercing depth or the needle is inserted as the user pushes on a needle cover. When the needle pierces into the body, the drug substance is expelled through the needle into the body. After injection, the autoinjector may withdraw the needle and cover it to prevent injury or the like. For example, such autoinjectors are described in EP 3 241 583 A1 , EP 3 389 746 B1 and EP 2 742 962 B1.

[0004] In development of autoinjectors or when setting up systems including syringes and autoinjectors to be used therewith, testing the setup including the autoinjector and the associated syringe is crucial. In particular, by testing the set up it is intended toachieve and assure proper and safe administration procedure. For example, breaking of the syringe when being used in an autoinjector may not only deteriorate or even render impossible administration of the drug substance, but also may cause danger to the patient and / or practitioner applying the syringe or autoinjector. Furthermore, standards relating to the application of syringes and / or autoinjectors exist which have to be met for regulatory or other reasons such as quality assurance.

[0005] When testing autoinjectors or setups of syringes with autoinjectors, one important aspect is to evaluate what forces are involved in administration. In particular, it may be important to consider plunger rod forces, glide forces, break loose forces, needle cover release forces and the like. At any instance of the administration process, it has to be assured that the forces involved do not impair the syringe or autoinjector and / or negatively affect the administration. Furthermore, needle protrusion may be important to consider as it is relevant for injection depth of the needle in use of the syringe or autoinjector.

[0006] Also, in other applications it may be desired by a manufacturer to test only the device or delivery system or autoinjector and / or its subassemblies. Different to design or development verification and release testing of a combined product being the product the patient receives, in such applications glide and other forces are not relevant and it is simply intended to test device related attributes such as syringe shuttling distance, activation forces and safety functionality such as needle cover displacement at a defined force and / or force to override the needle cover following use.

[0007] Testing syringes and autoinjectors often involves testing machines or force testing machines (FTM). Such machines allow to efficiently testing an appropriate number of syringes as well as to reliably and reproducibly testing the syringes at identical conditions. However, even though such testing machines increase efficiency of syringe and autoinjector testing, they involve a risk of damage of the machine and of injuring persons nearby. In particular, when glass syringes and / or syringes having needles are used, breaking the glass or the needles may be problematic. Further, using syringes filled with drug substances or other substances such as water for injection, may result in comparably high costs since a comparably high number of tests usually has to be performed.

[0008] Therefore, there is a need for a system or components thereof or for a method, allowing an efficient testing of autoinjectors particularly involving testing machines.Disclosure of the Invention

[0009] According to the invention this need is settled by a syringe surrogate as it is defined by the features of independent claim 1 , by an autoinjector as it is defined by the features of independent claim 17 and by a method as it is defined by the features of independent claim 20. Preferred embodiments are subject of the dependent claims.

[0010] In particular, in one aspect the invention is a syringe surrogate embodied to mimic a syringe in an autoinjector when the autoinjector is tested, also referred to as the syringe to be mimicked. The syringe surrogate comprises a longitudinal axis, a body portion, a flange portion and a needle portion. The body portion has a hollow interior, an open distal end and a proximal end. The flange portion is arranged at or near the distal end of the body portion.

[0011] The body portion extends along the longitudinal axis. The needle portion axially projects from the proximal end of the body portion. The flange portion is circumferentially arranged around the body portion, typically, near the distal end of the body portion. The body portion and the needle portion are made of a deformable material.

[0012] The term “surrogate” as used herein relates to a structure or component intended to replace another structure or component. More specifically, the syringe surrogate is a structure or component replacing a real syringe, for example, in a specific process such as a method of testing an autoinjector in which the syringe surrogate is arranged. Typically, surrogates are simpler in construction, more resistant to mechanical stress and / or cheaper in manufacture compared to the structure or component to be replaced. For example, the syringe surrogate does not need to have a real needle usually made of metal and a needle shield but has the needle portion which may be shaped as the needle, the needle shield or the needle cover instead. Furthermore, the syringe surrogate may be provided with improved properties relevant for the intended process such as testing the autoinjector. For example, the syringe surrogate may have an increased resistance with respect to breakage. The syringe surrogate, thus, is different from a real syringe at least in one aspect or property.

[0013] The term “distal” as used in connection with the syringe surrogate relates to a direction or orientation facing away from a patient in an intended use of the syringe mimicked by the syringe surrogate. Contrary, the term “proximal” relates to a direction, relative location or orientation opposite to distal. Thus, proximal can relate to an orientation of the syringe surrogate which in the intended use of the syringe it mimics is directed to a body of the patient. Thereby, proximal portions or parts can be directed to or positioned closer to the body of the patient when the syringe is applied to the patient. For example, in a conventional syringe the proximal end usually is the tip of the needle and the distal end is the end of the plunger where the thumb is to be positioned.

[0014] The body portion can particularly be essentially cylindrical. Thereby, essentially cylindrical can relate to be literally cylindrical and, also, to be slightly conical or to have a slightly changing diameter. For example, for still being understood as cylindrical, the outer radius of the syringe body may decrease or vary between the distal end and the proximal end within a range of 15% or less. Also, for being considered cylindrical, a length of the body portion between the distal and proximal ends may be considerably higher than the diameter. Still further, the cylindrical body portion may have a base shape of a polygon, an oval or, particularly, a circle. The cylinder may also have a taper, particularly on the internal surfaces to allow for easier manufacture - e.g. ejection from an injection molding machine.

[0015] The hollow interior of the body portion can be designed to receive a driver or plunger of the autoinjector or of a testing setup. Thereby, the plunger may be provided with or without a stopper or the syringe surrogate may be set into the autoinjector together with a stopper advanced into its interior. In any case, during testing the plunger typically is advanced through the open distal end of the body portion towards its proximal end.

[0016] The hollow interior can be sized for receiving about 1 ml or about 2 ml or about 5ml of fluid particularly a liquid. In such embodiments, the body portion may have a length in an axial direction in a range of about 51 .5 mm to about 54 mm such as 52.7 mm. The needle portion may have a total projection length in a range of about 21 .5 mm to about 23 mm such as 22.2 mm. The flange portion may have an axial extension in a range of about 1 .5 mm to about 2.5 mm such as 2 mm. An outer diameter of the body portion may be in a range of about 7 mm to about 10.5 mm such as increasing from about 7.8 mm at the proximal end to about 9.5 mm at the distal end. Or, particularly in body portions having a hollow interior, the outer diameter may be up to 18 mm or 17.2 mm.

[0017] The longitudinal axis typically extends centrally trough the body portion and the needle portion. In embodiments having a circle cylindrical body portion, the longitudinal axis extends through the center of the circle from the distal end to the proximal end. In embodiments having essentially rotational symmetric body portions, the longitudinal axis may be the axis of rotation.

[0018] The term “open” in connection with the distal opening related to an opening provided at the distal end. Such opening may allow to access the interior of the body portion. In particular, distal end can be open as to essentially the complete size of the interior of the body portion.

[0019] The term “near the distal end” can relate to be in a distance of about 20% of an axial length of the body portion or less. Thus, in addition to be located at or abutting the distal end this term covers a distance from the distal end which is smaller than 20% of the axial length of the body portion and, more specifically, smaller than 10% of the axial length.

[0020] The flange portion, can be embodied to essentially correspond to a finger flange of the syringe to be mimicked by the syringe surrogate. It can be positioned at or close to the distal end of the syringe body and it may circumvent the open end of the syringe body. The flange portion may outwardly or radially project over the outer circumference of the body portion.

[0021] The deformable material may particularly be elastically deformable. It can have a sufficient resiliency to prevent cracking when the syringe surrogate is used in an autoinjector being tested. Generally, the term deformable relates to the ability of a material or object to change in size or shape without breaking or fracturing. For example, ductility of a material may define the extent of deformability. In particular, by having a comparably high ductility, the material can con be comparably good for deformation. Typically, ductility is opposite to brittleness.

[0022] By the configuration in accordance with the invention, the syringe surrogate allows testing and measuring forces involved in use of the autoinjector. Thereby, since the syringe surrogate has a shape widely corresponding to the shape of the syringe to be used in the autoinjector, the involved forces can precisely be determined. Furthermore, since the material of the body and needle portions is deformable, cracking of the syringesurrogate during testing can be prevented. Thus, safety of the testing can be increased. Still further, the syringe surrogate can be manufactured at comparably low costs. Thus, the testing of multiple syringes under varying conditions can involve comparably low costs.

[0023] Furthermore, by including the needle portion the syringe surrogate allows to determine characteristics of the needle in use of the autoinjector. For example, a penetration depth and / or the amount the syringe is moved during initial or final stages of the injection / use cycle can be accurately measured or determined when the autoinjector is applied or used.

[0024] Preferably, the body portion, the needle portion and preferably the flange portion are monolithically formed. The term “monolithically formed” in this connection relates to the two or three portions being made as one piece. Thereby, the portions may be fixed together to form one piece, e.g. by gluing, screwing or the like, but, advantageously, they are one single uniform workpiece having specific sections, which form the three portions. Advantageously, the complete syringe surrogate, e.g. additionally comprising further portions such as a driver alignment portion, is monolithic. Such monolithic design of the syringe surrogate or configuration in one piece allows for an efficient manufacture and use. In particular, the essential two or three portions of or even the complete syringe surrogate can be manufactured in one step. An advantageous process of manufacture, may involve molding or injection molding the body portion, the flange portion and the needle portion.

[0025] Preferably, the body portion, the flange portion and the needle portion are made of the same deformable material. The term “same material” in this context may relate to chemical identity. Such chemically identical materials may still physically different or adapted, or may be physically identical as well. Such single material configuration allows for providing an efficiently manufacturable and robust construction.

[0026] Preferably, the deformable material is a polyoxymethylene (POM), a polyamide (PA), a polypropylene (PP), a plant based polymer material, an acrylonitrile butadiene styrene (ABS), or a non-crystalline plastic material. Such materials have proven to be suitable for efficient manufacture of the syringe surrogate and for appropriately mimicking the syringe to be used in the autoinjector at comparably low costs. Further, such materials may be robust, appropriately deformable and sufficiently resistant to loads and forcesinvolved in the injector, in particular, preventing breakage or the like. Still further, such material may be sustainable and recyclable.

[0027] Preferably, the needle portion has an outer shape in accordance with a needle cover of the syringe to be mimicked. The needle portion can be conveniently formed to be suitable for injection molding. In particular, the term “in accordance with the needle to be mimicked” may relate to the outer shape in fact being smaller on cross section compared to the regular needle cover or needle cover to be mimicked so it does not get gripped or stuck on a rigid needle shield remover component. The shape of the needle portion can be in any manner to correspond to the needle cover of the syringe. For example, as in many needle covers on the market, a cross section of the needle portion may be cross-like shaped. By shaping the needle portion in accordance with the needle cover of the syringe to be used in the autoinjector, the specific syringe configuration involved can efficiently be mimicked.

[0028] Preferably, the syringe surrogate comprises a driver alignment portion proximally extending from the flange portion. Such driver alignment portion may assure proper application of a plunger or driver, and / or other components of the autoinjector to the syringe surrogate. For example, the driver of the autoinjector may involve the plunger or a similar element for operating the syringe. By the driver alignment portion, it can be achieved that the provision of the plunger of the autoinjector or properly provided into the interior of the syringe surrogate. Additionally, it can be attained that the syringe surrogate is properly arranged and orientated in the autoinjector.

[0029] Thereby, the body portion and the driver alignment portion preferably have a reduced outer diameter relative to the flange portion. Like this, the flange portion allows to mimic the finger flange of the syringe to be used in the autoinjector.

[0030] Preferably, a vent opening is provided in a proximal region of the body portion. Such vent opening or vent hole allows to provide gas or, eventually, another fluid such as a liquid out of the interior or the body portion, when the plunger of the autoinjector is forwarded through the open end into the interior of the body portion. Particularly, in embodiments having a solid needle portion or a needle portion not including a channel, such configuration may be beneficial or mandatory.

[0031] The vent opening can be embodied as bore in a wall of the body portion. It can be provided in the proximal end of the body portion and, more specifically, in a section of the proximal end aside the needle portion. Alternatively, the vent opening may be provided in a side wall of the body portion near to the proximal end.

[0032] For properly mimicking advancing the driver or plunger of the autoinjector and for preventing provision of excess forces or stress to the proximal end of the body portion or sections close thereto, the syringe surrogate can be provided with a structure slowing down the movement of the plunger when it approaches the proximal end of the body part. In particular, the following features can be embodied to the syringe surrogate in order to achieve such effect. Thereby, the features of the following embodiments can be implemented alone or in combination with each other.

[0033] In one embodiment, the proximal end of the body portion is equipped with at least one axial crush rib extending along the longitudinal axis, preferably from the proximal end. In another embodiment, the proximal end of the body portion is equipped with at least one radial crush rib perpendicularly extending to the longitudinal axis. Such axial or radial crush ribs may achieve efficient deceleration of the driver or plunger. Further such crush ribs may be efficiently manufacturable particularly when the body portion is molded.

[0034] Advantageously, the axial crush rib and / or the radial crush rib may be positioned in the proximal end region, defined as being within approximately 20% of the axial length of the body portion or less. Such design of the crush rib allows for efficiently slowing down a plunger of the autoinjector in operation at a desired location, i.e. when approaching the proximal end of the syringe surrogate.

[0035] In a particularly sophisticated embodiment, the body portion comprises at least one spring structure resiliently extending into the interior of the body portion. Such spring structure allows to accurately define a course of deceleration of the plunger. The spring structure can be integrally formed in the body portion. Due to the deformable material and particularly elastically deformable material of the body portion, sufficient or appropriate resiliency can be provided by the properties of the material.

[0036] Thereby, the at least one spring structure preferably comprises a spring tab resiliently extending into the interior of the body portion. The spring tab may be tonguelike shaped. Advantageously, there are plural spring structures or spring tabs arranged around the body portion. Like this, a balanced deceleration can be achieved.

[0037] The at least one spring tab preferably is formed by a U-shaped opening in a side wall of the body portion. Such cut-out or opening allows for efficiently manufacturing the at least one spring structure. It further may form a vent opening or vent hole.

[0038] Preferably, the spring structure is arranged in a proximal end region of the body portion. Such proximal end region may be defined in a distance of about 20% of the axial length of the body portion or less. The spring structure close to the proximal end allows for efficiently slowing down the plunger of the autoinjector where required.

[0039] Advantageously, the proximal end region, where the spring structure, the axial crush rib and / or the radial crush rib is located, partially or entirely covers a portion of the barrel corresponding to a respective portion of the syringe to be mimicked in the autoinjector involved in a phase following a drug delivery phase of the autoinjector. Typically, this portion is comparably close to the proximal end of the body portion and may extend into a distal direction. Particularly in such configuration, the spring structure, the axial crush rib and / or the radial crush rib can efficiently function as a high-speed energy damping mechanism on the plunger of the autoinjector, thereby preventing damage and / or breakage to the syringe surrogate and / or the autoinjector. Furthermore, the motion of the plunger may not be affected by the spring structure in the region preceding the proximal end region of the barrel.

[0040] Preferably, the needle portion is equipped with a bore longitudinally extending through the needle portion. Such bore may be relevant for mimicking the needle behaviour and / or plunger force behaviour when testing the autoinjector. For example, it allows for measuring the plunger force of the autoinjector using a probe attached to a moving load cell such as those found on common force or displacement testing machines. Specifically, a pressure or force probe may be inserted through the bore into the hollow interior of the body portion, such that a plunger force may be measured without introducing significant additional forces, e.g., caused by friction. Furthermore, it may implement a vent opening or hole.

[0041] Preferably, the proximal end of the body portion is accessible through the open distal end and the hollow interior. Advantageously, the proximal end is freely accessiblethrough the open distal end such that a plunger and / or stopper of the autoinjector to be tested can conveniently or unhinderedly enter the body portion or the hollow interior thereof. Specifically, the proximal end of the body portion may be accessible at its back side or distal side. In typical embodiments, the proximal end is the end of the body portion where in a real syringe a needle is either mounted, e.g. stacked-in, or to be coupled such as via a Luer lock adaptor or the like. Particularly, it is advantageous that no stopper is provided within the syringe surrogate. This allows using the syringe surrogate for testing without introducing friction and hydraulic forces that may introduce noise or invalidate measurements.

[0042] Preferably, the syringe surrogate comprises a pressure or force probe arrangeable or arranged in the hollow interior of the body portion. Such force probe allows to efficiently test the autoinjector’s plunger rod force.

[0043] In another aspect, the invention is an autoinjector comprising a syringe seat and a syringe surrogate as described above, wherein the syringe surrogate is arranged in the syringe seat. The syringe seat may be any suitable structure capable of arranging or holding the syringe surrogate in a predefined position. The autoinjector may be embodied for being used in drug administration, wherein, for testing purposes, it is equipped with the syringe surrogate.

[0044] Such an autoinjector and its preferred embodiments described below allow for efficiently achieving the effects and benefits set forth in connection with the syringe surrogate and its preferred embodiments described above. In particular, the autoinjector may provide a ready to use unit for being tested, e.g., in a force testing machine.

[0045] Preferably, the autoinjector comprises a plunger and is configured such that the plunger can be advanced into the hollow interior of the body portion of the syringe surrogate. Such plunger can be embodied to be forwarded in a body of the syringe to be tested for expelling a drug substance out of the syringe.

[0046] Preferably, the autoinjector comprises a pressure or force probe arrangeable or arranged in the hollow interior of the body portion of the syringe surrogate. The pressure or force probe can be embodied to be introduced through the needle portion of the syringe surrogate into the hollow interior of the body portion. Like this, the pressure or force probe can be provided after the syringe surrogate is set in the syringe seat of the autoinjector.Or, the pressure or force probe can be arranged in the hollow interior when the syringe surrogate is set in the syringe seat of the autoinjector already. In any case, the pressure or force probe allows to efficiently evaluate the pressure or force situation during operation of the autoinjector.

[0047] In a further other aspect, the invention is a method of testing an autoinjector, comprising the steps of: obtaining the autoinjector; setting a syringe surrogate as described above into the autoinjector; positioning the autoinjector with the syringe surrogate in a force testing machine, and measuring forces involved in application of the autoinjector.

[0048] Setting the syringe surrogate into the autoinjector may result in an autoinjector according to the invention as described above. Particularly, if the autoinjector involved in the method includes a syringe seat and if the syringe surrogate is received by the syringe seat when being set in the autoinjector, the autoinjector according to the invention as described above may be embodied.

[0049] Such a testing method and its preferred embodiments described below allows for efficiently achieving the effects and benefits set forth in connection with the syringe surrogate and its preferred embodiments described above. In particular, the method allows for efficiently testing the autoinjector with comparably high accuracy, at comparably low costs and in a comparably safe manner.

[0050] Preferably, the method includes a step of measuring a distance by which the needle portion protrudes out of the autoinjector. In particular, such measurement can be helpful after activation of the autoinjector in order to determine a penetration depth of the needle portion of the syringe surrogate.

[0051] Preferably, in the step of setting the syringe surrogate into the autoinjector, the hollow interior of the body portion is kept accessible through the open distal end such that a plunger of the autoinjector can be introduced into the hollow interior through the open distal end. Such embodiment with a freely accessible open end allows for efficient application or use in an autoinjector to be tested. In particular, the structure of the autoinjector embodied to activate the syringe can be directly used for testing. This allows for generating comparably meaningful and reliable test results by realistic mimicking and testing of the operation of the autoinjector.

[0052] Advantageously, the method includes using the syringe surrogate excluding a stopper. Like this, it can be prevented that the plunger of the autoinjector is affected by hydraulic or frictional forces related to the stopper. This may enable the isolation and measurement of the autoinjector’s force without the interference of external influence which would introduce noise in the measurementBrief Description of the Drawings

[0053] The syringe surrogate according to the invention, the autoinjector according to the invention and the method of testing an autoinjector according to the invention are described in more detail hereinbelow by way of exemplary embodiments and with reference to the attached drawings, in which:Fig. 1 shows a perspective view of a first embodiment of a syringe surrogate according to the invention;Fig. 2 shows a side view of the syringe surrogate of Fig. 1 ;Fig. 3 shows a front view of the syringe surrogate of Fig. 1 ;Fig. 4 shows a cross sectional view along the line A-A of Fig. 2;Fig. 5 shows a perspective view of a second embodiment of a syringe surrogate according to the invention;Fig. 6 shows a side view of the syringe surrogate of Fig. 5;Fig. 7 shows a back view of the syringe surrogate of Fig. 5;Fig. 8 shows a cross sectional view along the line A-A of Fig. 6;Fig. 9 shows a perspective view of a third embodiment of a syringe surrogate according to the invention;Fig. 10 shows a side view of the syringe surrogate of Fig. 9;Fig. 11 shows a back view of the syringe surrogate of Fig. 9;Fig. 12 shows a cross sectional view along the line A-A of Fig. 10;Fig. 13 shows a perspective view of a fourth embodiment of a syringe surrogate according to the invention;Fig. 14 shows a side view of the syringe surrogate of Fig. 13;Fig. 15 shows a back view of the syringe surrogate of Fig. 13;Fig. 16 show a cross sectional view along the line A-A of Fig. 14;Fig. 17 shows a perspective view of a fifth embodiment of a syringe surrogate according to the invention;Fig. 18 shows a side view of the syringe surrogate of Fig. 17;Fig. 19 shows a back view of the syringe surrogate of Fig. 17;Fig. 20 shows a cross sectional view along the line A-A of Fig. 18;Fig. 21 shows a schematic view of an embodiment of an autoinjector according to the invention including the syringe surrogate of Fig. 1 .of Embodiments

[0054] In the following description certain terms are used for reasons of convenience and are not intended to limit the invention. The terms “right”, “left”, “up”, “down”, “under" and “above" refer to directions in the figures. The terminology comprises the explicitly mentioned terms as well as their derivations and terms with a similar meaning. Also, spatially relative terms, such as "beneath", "below", "lower", "above", "upper", "proximal", "distal", and the like, may be used to describe one element's or feature's relationship to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass different positions and orientations of the devices in use or operation in addition to the position and orientation shown in the figures. For example, if a device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be "above" or "over" the other elements or features. Thus, the exemplary term "below" can encompass both positions and orientations of above and below. The devices may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein interpreted accordingly. Likewise, descriptions of movement along and around various axes include various special device positions and orientations.

[0055] To avoid repetition in the figures and the descriptions of the various aspects and illustrative embodiments, it should be understood that many features are common to many aspects and embodiments. Omission of an aspect from a description or figure does not imply that the aspect is missing from embodiments that incorporate that aspect. Instead, the aspect may have been omitted for clarity and to avoid prolix description. In this context, the following applies to the rest of this description: If, in order to clarify the drawings, a figure contains reference signs which are not explained in the directly associated part of the description, then it is referred to previous or following description sections. Further, for reason of lucidity, if in a drawing not all features of a part are provided with reference signs it is referred to other drawings showing the same part. Like numbers in two or more figures represent the same or similar elements.

[0056] Fig. 1 and Fig. 2 show a first embodiment of a syringe surrogate 1 according to the invention. The syringe surrogate 1 is a monolithic structure molded of a plant based polymer as deformable material. It comprises a body portion 2, a needle portion 3 and a flange portion 4.

[0057] The body portion 2 is essentially cy I indric. It has an open distal end 23, a proximal end 22 and a cylinder wall 24. Close to the proximal end 22, the body portion 2 is provided with a vent hole 21 or vent opening.

[0058] The needle portion 3 proximally extends from the proximal end 22 of the body portion 2. As can be best seen in Fig. 3, it has an essentially cross-shaped cross section and proximally ends in a cross shaped end face 31 . In particular, the outer shape of the needle portion 3 corresponds to the outer shape of a needle cover of a syringe to be mimicked by the syringe surrogate 1 .

[0059] The flange portion 4 is ring shaped and extends circumferentially around the open distal end 23 of the syringe body 2. It radially projects above the body portion 2. In other words, an outer diameter of the flange portion 4 is larger than an outer diameter of the body portion 2.

[0060] In Fig. 4 a longitudinal axis 5 of the syringe surrogate 1 and an interior 25 of the body portion 2 is shown. The vent hole 21 connects the interior 25 to the outside of the body portion 2 through the cylinder wall 24. Further, the vent hole 21 is adjacent to the proximal end 22 of the body portion 2. In contrast to the body portion 2, the needle portion 3 is solid and does not include a bore or another opening. The longitudinal axis 5 extends centrally trough the body portion 2 and the needle portion 3.

[0061] The proximal end 22 is freely accessible through the open distal end 23 such that a plunger and / or stopper of the autoinjector to be tested can conveniently or unhinderedly enter the body portion 2 or the interior 25 thereof. Specifically, the proximal end 22 of the body portion 2 is accessible at its back side or distal side through the hollow interior 25.

[0062] Fig. 5 and Fig. 6 show a second embodiment of a monolithic syringe surrogate 100 according to the invention. The second syringe surrogate 100 is similarly embodied as the first syringe surrogate 1 shown in Figs. 1 to 4. In particular, the second syringe surrogate 100 has an identical needle portion 300 with an essentially cross shaped endface 3100, a body portion 200 with an identical cylinder wall 2400, proximal end 2200, distal end 2300 and a hollow interior 2500, an identical longitudinal axis 500 and an identical flange portion 400.

[0063] In a first aspect different from the first syringe surrogate 1 , as can be best seen in Fig. 7 showing the second syringe surrogate 100 from a back side, in the second syringe surrogate 100 a vent hole 2100 is provided through the proximal end side 2200 and radially aside the needle portion 300.

[0064] In a second aspect different from the first syringe surrogate 1 , the second syringe surrogate 100 comprises a driver alignment portion 600. The driver alignment portion 600 distally extends from the flange portion 400. It is ring shaped and has an outer diameter smaller than the outer diameter of the flange portion 400. As can be best seen in Fig. 8, an inner diameter of the driver alignment portion 600 widens starting from an inner diameter of the body portion 200 to a slightly larger inner diameter at the distal end of the driver alignment portion 600. By this configuration a plunger or driver of the autoinjector can be conveniently received and accurately centred when the syringe surrogate 100 is arranged in the autoinjector.

[0065] In a third aspect different from the first syringe surrogate 1 , the body portion 200 of the second syringe surrogate 100 is equipped with four axial crush ribs 2600 as deceleration structure. The crush ribs 2600 are located at the cylinder wall 2400 adjoining the proximal end side 2200. They radially extend into the interior 2500 of the body portion 200. In particular, the axial crush ribs 2600 increase towards the distal end 2200.

[0066] By means of the axial crush ribs 2600 the plunger or driver of the autoinjector is slowed down when approaching the proximal end 2200 while being advanced into the hollow interior 2500. In particular, when axially moving into the hollow interior 2500 the axial crush ribs 2600 increasingly decelerate the plunger or driver when getting closer to the distal end 2200. Thereby, it is prevented that the plunger or driver hits the distal end 2200 at comparably high speed which might damage the syringe surrogate 100.

[0067] Fig. 9 and Fig. 10 show a third embodiment of a monolithic syringe surrogate 101 according to the invention. The syringe surrogate 101 is similarly embodied as the second syringe surrogate 100 shown in Figs. 5 to 8. In particular, the third syringe surrogate 101 has an identical needle portion 301 with an essentially cross shaped endface 3101 , a body portion 201 with an identical cylinder wall 2401 , proximal end 2201 , distal end 2301 , hollow interior 2501 and vent hole 2101 , an identical longitudinal axis 501 , an identical flange portion 401 and an identical driver alignment portion 601.

[0068] Different from the second syringe surrogate 100, as can be seen in Figs. 11 and 12, in the third syringe surrogate 101 crush ribs 2601 are provided radially rather than axially. Thereby, the radial crush ribs 2601 form a cross on the distal end 2201 of the body portion 201. In use the radial crush ribs 2601 achieve deceleration of a plunger or driver when getting close to the distal end 2201 . Thereby, it is safely prevented that the plunger or driver abuts the distal end 2201 at comparably high speed which might damage or break the syringe surrogate 101 .

[0069] Fig. 13 shows a fourth embodiment of a monolithic syringe surrogate 102 according to the invention. The syringe surrogate 102 is a monolithic component molded of an appropriate material and comprises a body portion 202, a needle portion 302 and a flange portion 402.

[0070] The body portion 202 is essentially cylindrical. It has a proximal end 2202 and a cylinder wall 2402. Close to the proximal end 2202, the body portion 202 is provided with two opposite spring structures 2602 as deceleration structure. Each spring structure 2602 comprises a spring tab 2612 resiliently extending into an interior 2502 of the body portion 202.

[0071] As can be seen in Fig. 14, in each spring structure 2602 the spring tab 2612 is formed by a U-shaped opening 2622 in a cylindrical side wall 2402 of the body portion 202. In particular, the U-shaped opening 2622 forms the tongue-like elastic spring tab 2612. Thereby, in addition to forming the spring tab 2612, the U-shaped opening 2622 implements a vent hole of the body portion 2202.

[0072] Referring to Fig. 15 and Fig. 16, the elastic spring tabs 2612 of the two opposite spring structures are bent inwardly towards a longitudinal axis 502 into an interior 2502 of the body portion 202. Thereby, the interior 2502 of the body portion 202 is flexibly narrowed towards the proximal end 2202. The axis 502 extends centrally through the body portion 202 and the needle portion 302.

[0073] In use of the syringe surrogate 102, when a plunger or driver is advanced into the interior 2502, the movement of the driver or plunger is slowed down whenapproaching the proximal end 2202 of the body portion. Specifically, the spring tabs 2612 are flexibly deformed in a radial direction and press on the plunger or driver by means of their spring forces. Thus, the plunger or driver is clamped in between the spring tabs 2612 such that a resistance of advancing the plunger or driver increases.

[0074] The needle portion 302 is solidly formed and proximally extends from the proximal end 2202 of the body portion 202 into a proximal direction along the axis 502. The proximal end 2202 is equipped with a transversal strengthening rib 2212 which provides additional strength and resistance for breakage. The flange portion 402 circumferentially extends around an open distal end 2302. It radially projects above the body portion 202. In other words, an outer diameter of the flange portion 402 is larger than an outer diameter of the body portion 202.

[0075] The outer shape of the needle portion 302 corresponds to the outer shape of a needle cover of a syringe to be mimicked by the syringe surrogate 102. Turning back to Fig. 13, the needle portion 302 has an essentially cross-shaped cross section and proximally ends in a cross shaped end face 3102. Further, the flange portion 402 is not strictly circular ring shaped but has two straightened gripping sections 4102 opposite each other. More specifically, the gripping sections 4102 of the flange portion 402 are aligned to the spring structures 2602.

[0076] Fig. 17, Fig. 18, Fig. 19 and Fig. 20 show a fifth embodiment of a monolithic syringe surrogate 103 according to the invention. The syringe surrogate 103 is similarly embodied as the second syringe surrogate 100 shown in Figs. 5 to 8. In particular, the fifth syringe surrogate 103 has an identical body portion 203 with an identical cylinder wall 2403, proximal end 2203, distal end 2303, hollow interior 2503 and axial crush ribs 2603 forming a cross on the distal end 2203, an identical longitudinal axis 503, an identical flange portion 403 and an identical driver alignment portion 603.

[0077] Different from the second syringe surrogate 100, as can be best seen in Fig. 20, the fifth syringe surrogate 103 has a different needle portion 303. In particular, the needle portion 303 has a slightly tapering circular cylindrical outer surface. It is further equipped with a bore 3203 longitudinally extending all through the needle portion 303 form the interior 2503 of the body portion 203 to the outside. Beyond others, the bore 3203 works as a vent hole for the interior 2503 of the body portion 203. Further, it may be used for advancing a pressure or force probe inside the hollow interior 2503.

[0078] As can be best seen in Fig. 17 and Fig. 19, the needle portion 303 has a ringshaped end face 3103. Further, compared to the second syringe surrogate 100, the body portion 203 of the fifth syringe surrogate 103 lacks an own vent hole in the cylinder wall 2403 or in the proximal end 2303.

[0079] Fig. 21 shows a schematic view of an embodiment of an autoinjector 8 according to the invention. The autoinjector 8 comprising a syringe seat 81 and, exemplarily, the first embodiment of a syringe surrogate 1 described above in connection with Figs. 1 to 4. In particular, the syringe surrogate 1 is set in the syringe seat 81 which firmly holds the syringe surrogate in a predefined position.

[0080] The autoinjector 8 further comprises a plunger 82 configured such that the it can be advanced into the hollow interior 25 of the body portion 2 of the syringe surrogate 1 . In particular, whereas the plunger 82 is embodied to activate a real syringe for administering a drug stored inside the syringe, the design of the syringe surrogate 1 allows to apply the plunger 82 for force and other testing without being further modified in a force testing machine 9.

[0081] In order to be capable of efficiently being used in a force testing machine, the autoinjector 8 comprises a force probe 7 arranged in the hollow interior 25 of the body portion 2 of the syringe surrogate 1 . The type of force probe 7 schematically depicted in Fig. 21 is particularly suitable for a force testing method using syringe surrogates with a closed or solid needle portion such as the first embodiment of syringe surrogate 1. Alternatively, a syringe surrogate with an open needle portion can be used, such as the fourth embodiment of syringe surrogate 103 as shown in Figs. 17 to 20. Involving such syringe surrogate 103, allows for providing a suitable pressure probe through the bore 3203 of the needle portion 303.

[0082] This description and the accompanying drawings that illustrate aspects and embodiments of the present invention should not be taken as limiting-the claims defining the protected invention. In other words, while the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of this description and the claims. In some instances, well-known circuits, structures and techniques have not been shown in detailin order not to obscure the invention. Thus, it will be understood that changes and modifications may be made by those of ordinary skill within the scope and spirit of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below.

[0083] The disclosure also covers all further features shown in the Figs, individually although they may not have been described in the afore or following description. Also, single alternatives of the embodiments described in the figures and the description and single alternatives of features thereof can be disclaimed from the subject matter of the invention or from disclosed subject matter. The disclosure comprises subject matter consisting of the features defined in the claims or the exemplary embodiments as well as subject matter comprising said features. Also, the present disclosure covers intermediate generalisations of features or groups of features of the embodiments described and shown in the figures. I.e., specific features or groups of features as disclosed in the figures and the associated sections of the description may be combined with the more general embodiments of the invention disclosed in connection with the description of the invention. In particular, such specific features or groups of features may be provided in the more general embodiments of the invention in isolation from further specific features shown in the figures. For example, the vent hole in the proximal end of the body portion as shown in the Figs, can be provided in the syringe surrogate according to the invention, e.g., having in addition at least one spring tab. It is understood that those skilled in the art are able to incorporate specific features from the description of the figures into the embodiments of the description of the invention.

[0084] Furthermore, in the claims the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single unit or step may fulfil the functions of several features recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The terms “essentially”, “about”, “approximately” and the like in connection with an attribute or a value particularly also define exactly the attribute or exactly the value, respectively. The term “about” in the context of a given numerate value or range refers to a value or range that is, e.g., within 20%, within 10%, within 5%, or within 2% of the given value or range. Components described as coupled or connected may be electrically or mechanically directly coupled, or they may be indirectly coupled via one or more intermediatecomponents. Any reference signs in the claims should not be construed as limiting the scope.List of Reference Signs1 syringe surrogate 401 flange portion2 body portion 501 longitudinal axis21 vent hole 601 driver alignment portion22 proximal end 102 syringe surrogate23 distal end 23 202 body portion24 cylinder wall 2202 proximal end25 interior 2302 distal end3 needle portion 2402 cylinder wall 31 end face 2502 interior4 flange portion 2602 spring structures5 longitudinal axis 2612 spring tab100 syringe surrogate 2622 U-shaped opening200 body portion 302 needle portion2100 vent hole 3102 end face2200 proximal end 402 flange portion2300 distal end 502 longitudinal axis2400 cylinder wall 103 syringe surrogate2500 interior 203 body portion2600 crush ribs 2203 proximal end side300 needle portion 2303 distal end side3100 end face 2403 cylinder wall 400 flange portion 2503 interior 500 longitudinal axis 2603 crush ribs600 driver alignment portion 303 needle portion101 syringe surrogate 3103 end face201 body portion 3203 bore2101 vent hole 403 flange portion2201 proximal end 503 longitudinal axis2301 distal end 603 driver alignment portion2401 cylinder wall 7 force probe2501 interior 8 autoinjector2601 crush ribs 81 syringe seat301 needle portion 82 Plunger3101 end face 9 force testing machine

Claims

CLAIMS1. A syringe surrogate (1 ; 100; 101 ; 102; 103) to mimic a syringe in an autoinjector when the autoinjector is tested, the syringe surrogate (1 ; 100; 101 ; 102; 103) comprising: a longitudinal axis (5; 500; 501 ; 502; 503); a body portion (2; 200; 201 ; 202; 203) with a hollow interior (25; 2500; 2501 ; 2502; 2503), an open distal end (23; 2300; 2301 ; 2302; 2303) and a proximal end (22; 2200; 2201 ; 2202; 2203); a flange portion (4; 400; 401 ; 402; 403) at or near the distal end (23; 2300; 2301 ; 2302; 2303) of the body portion (2; 200; 201 ; 202; 203); and a needle portion (3; 300; 301 ; 302; 303); wherein the body portion (2; 200; 201 ; 202; 203) extends along the longitudinal axis (5; 500; 501 ; 502; 503), wherein the needle portion (3; 300; 301 ; 302; 303) axially projects from the proximal end (22; 2200; 2201 ; 2202; 2203) of the body portion (2; 200; 201 ; 202; 203), wherein the flange portion (4; 400; 401 ; 402; 403) is circumferentially arranged around the body portion (2; 200; 201 ; 202; 203), and wherein the body portion (2; 200; 201 ; 202; 203) and the needle portion (3; 300; 301 ; 302; 303) are made of a deformable material.

2. The syringe surrogate (1 ; 100; 101 ; 102; 103) of claim 1 , wherein the body portion (2; 200; 201 ; 202; 203), the needle portion (3; 300; 301 ; 302; 303) and preferably the flange portion (4; 400; 401 ; 402; 403) are monolithically formed.

3. The syringe surrogate (1 ; 100; 101 ; 102; 103) of claim 1 or 2, wherein the body portion (2; 200; 201 ; 202; 203), the flange portion (4; 400; 401 ; 402; 403) and the needle portion (3; 300; 301 ; 302; 303) are made of the same deformable material.

4. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein the deformable material is a polypropylene, a plant based polymer material, an acrylonitrile butadiene styrene, or a non-crystalline plastic material.

5. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein the needle portion (3; 300; 301 ; 302; 303) has an outer shape in accordance with a needle cover of the syringe to be mimicked.

6. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, comprising a driver alignment portion (600; 601 ; 603) proximally extending from the flange portion (4; 400; 401 ; 402; 403).

7. The syringe surrogate (1 ; 100; 101 ; 102; 103) of claim 6, wherein the body portion (2; 200; 201 ; 202; 203) and the driver alignment portion (600; 601 ; 603) have a reduced outer diameter relative to the flange portion (4; 400; 401 ; 402; 403).

8. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein a vent opening (21 ; 2100; 2101 ; 2612; 3203) is provided in a proximal region of the body portion (2; 200; 201 ; 202; 203).

9. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein the proximal end (22; 2200; 2201 ; 2202; 2203) of the body portion (2; 200; 201 ; 202; 203) is equipped with at least one axial crush rib (2600; 2603) extending along the longitudinal axis (5; 500; 501 ; 502; 503).

10. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein the proximal end (22; 2200; 2201 ; 2202; 2203) of the body portion (2; 200; 201 ; 202; 203) is equipped with at least one radial crush rib (2601 ) perpendicularly extending to the longitudinal axis (5; 500; 501 ; 502; 503).11 . The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein the needle portion (3; 300; 301 ; 302; 303) is equipped with a bore (3203) longitudinally extending through the needle portion (3; 300; 301 ; 302; 303).

12. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein the body portion (2; 200; 201 ; 202; 203) comprises at least one spring structure (2602) resil iently extending into the interior (25; 2500; 2501 ; 2502; 2503) of the body portion (2; 200; 201 ; 202; 203).

13. The syringe surrogate (1 ; 100; 101 ; 102; 103) of claim 12, wherein the at least one spring structure (2602) comprises a spring tab (2612) resiliently extending into the interior (25; 2500; 2501 ; 2502; 2503) of the body portion (2; 200; 201 ; 202; 203), wherein the at least one spring tab (2612) preferably is formed by a U-shaped opening (2622) in a side wall (24; 2400; 2401 ; 2402) of the body portion (2; 200; 201 ; 202; 203).

14. The syringe surrogate (1 ; 100; 101 ; 102; 103) of claim 12 or 13, wherein the spring structure (2602) is arranged in a proximal end region of the body portion (2; 200; 201 ; 202; 203).

15. The syringe surrogate (1 ; 100; 101 ; 102; 103) of any one of the preceding claims, wherein the proximal end (22; 2200; 2201 ; 2202; 2203) of the body portion (2; 200; 201 ; 202; 203) is accessible through the open distal end (23; 2300; 2301 ; 2302; 2303) and the hollow interior (25; 2500; 2501 ; 2502; 2503).

16. The syringe surrogate (1 ; 100; 101 ; 102; 103) according to any one of the preceding claims, comprising a force probe (3) arrangeable in the hollow interior (25; 2500; 2501 ; 2502; 2503) of the body portion (2; 200; 201 ; 202; 203).

17. An autoinjector (8) comprising a syringe seat (81 ) and a syringe surrogate (1 ; 100; 101 ; 102; 103) according to any one of the preceding claims, wherein the syringe surrogate (1 ; 100; 101 ; 102; 103) is arranged in the syringe seat (81 ).

18. The autoinjector (8) of claim 17, comprising a plunger (82) and configured such that the plunger (82) is advanceable into the hollow interior (25; 2500; 2501 ; 2502; 2503) of the body portion (2; 200; 201 ; 202; 203) of the syringe surrogate (1 ; 100; 101 ; 102; 103).

19. The autoinjector (8) of claim 17 or 18, comprising a force probe (7) arrangeable in the hollow interior (25; 2500; 2501 ; 2502; 2503) of the body portion (2; 200; 201 ; 202; 203) of the syringe surrogate (1 ; 100; 101 ; 102; 103).

20. A method of testing an autoinjector (8), comprising obtaining the autoinjector (8), setting a syringe surrogate (1 ; 100; 101 ; 102; 103) according to any one of claims 1 to 16 into the autoinjector (8), positioning the autoinjector (8) with the syringe surrogate (1 ; 100; 101 ;102; 103) in a force testing machine (9), and measuring forces involved in application of the autoinjector (8).21 . The method of claim 20, wherein, when setting the syringe surrogate (1 ; 100; 101 ; 102; 103) into the autoinjector (8), the hollow interior (25; 2500; 2501 ; 2502; 2503) of the body portion (2; 200; 201 ; 202; 203) is kept accessible through the open distal end (23; 2300; 2301 ; 2302; 2303) such that a plunger (82) of the autoinjector (8) is introducible into the hollow interior (25; 2500; 2501 ; 2502; 2503) through the open distal end (23; 2300; 2301 ; 2302; 2303).

22. The method of claim 20 or 21 , comprising a step of measuring a distance by which the needle portion protrudes out of the autoinjector (8).

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