HK40090916A - Plunger and finger grip for a syringe assembly, method for making them, syringe assembly, kit and use of the same - Google Patents

Description

plungers and finger grippers for syringe assemblies, their manufacturing methods, syringe assemblies, kits, and usage methods.

Technical Field

The present invention relates to a plunger for a syringe assembly for administering a liquid composition and a method for manufacturing such a plunger, wherein the plunger includes a plunger rod and a plunger head, wherein the plunger rod includes a proximal end and a distal end, and wherein the plunger head is attached to the proximal end of the plunger rod and includes a proximal-facing surface configured to act as a thumbplate during administration.

Furthermore, the present invention relates to a finger gripper for a syringe assembly for administering a liquid composition, and to a method for manufacturing such a finger gripper, wherein the finger gripper includes a finger gripper body having two flanges extending radially in opposite directions from a central hole in the finger gripper body, through which a plunger of the syringe assembly can be inserted, each flange acting as a gripping portion and having a finger contact area, wherein at least one of the user's fingers can be partially placed on the finger contact area during administration to support the finger during administration, wherein each flange includes a proximal surface and a distal surface.

Furthermore, the present invention relates to a syringe assembly for administering a liquid composition to a human or animal body, comprising at least a longitudinal syringe barrel having an inner cavity for receiving and storing the liquid composition to be administered, a finger gripper coupled to a proximal end of said barrel, and a plunger having a plunger rod and a plunger head, wherein the distal end of the plunger rod is at least partially disposed within the inner cavity of the barrel.

Furthermore, the present invention relates to a kit of components including a specified syringe assembly.

Furthermore, the present invention relates to the use of the aforementioned syringe components or kits for cosmetic or therapeutic applications, particularly for replacing or filling biological tissue or increasing the volume of biological tissue.

Background Technology

Syringe assemblies for administering liquid compositions and kits comprising several parts for assembling the syringe (particularly including at least a syringe barrel, a finger gripper, and a plunger with a plunger rod and a plunger head) are known in the prior art for a wide range of applications.

Injection devices are known from the prior art, for example, comprising a syringe barrel having a body with a piston having an open end therein, the syringe barrel being pre-filled with a viscous fluid. A needle assembly is provided comprising a cannula having a locking connection for engagement with a distal end of a syringe having a Luer connector including a hub. A mating engagement is provided by the internal threads of the distal end of the syringe and the external threads of the hub, wherein the pitch is sufficient to prevent the hub from separating from the distal end of the syringe during the ejection of the viscous fluid from the syringe barrel. Furthermore, a specially designed hub further prevents the hub from separating from the distal end of the syringe during the ejection of the viscous fluid.

In addition, syringe assemblies for delivering fluids are known, wherein the syringe assembly includes a plunger device and a disposable cartridge configured to contain the fluid to be delivered, wherein the disposable cartridge includes a container defining a chamber for the fluid, and a protective device configured to seal and insulate the chamber relative to the outside.

Additionally, prior art is known for syringe assemblies for delivering fluids, wherein the syringe assembly includes a plunger device and a disposable cartridge configured to contain the fluid to be delivered, wherein the disposable cartridge includes a container defining a chamber for the fluid and is provided with a threaded collar to which a fluid delivery device can be detachably screwed.

Furthermore, aspiration and injection devices are known that can economically, safely, and accurately aspirate from a target site and spray medication onto that site. The device may include a syringe barrel, a flange expander connectable to the barrel, and a plunger that can be engaged by the user's hand and/or one or more fingers to perform aspiration and injection at the target site.

In addition, it is known to use a tip cap to close and/or seal the distal end of the syringe barrel.

Furthermore, methods for manufacturing syringe assemblies and kits according to specifications, as well as methods for manufacturing individual components of syringe assemblies or kits, are generally known. Specifically, methods for manufacturing syringe barrels, plungers, and/or finger grippers are known in the prior art.

Furthermore, existing technologies know of methods for manufacturing syringe barrels that include an application step of applying silicone oil to the inner surface of the barrel by spraying non-reactive silicone oil onto the inner surface, and a heating step of heating the applied silicone oil to reduce its viscosity. The inner surface of the syringe barrel is coated with non-reactive silicone oil with a viscosity of 3000 to 30000 cps. The proportion of silicone oil in the coating is no more than 20%.

Purpose of the invention

In view of the above, one object of the present invention is to provide an alternative plunger, particularly an improved plunger, for a syringe assembly for administering a liquid composition. Another object is to provide a method for manufacturing a plunger for a syringe assembly, to provide an alternative finger gripper for a syringe assembly, particularly an improved finger gripper, to provide a method for manufacturing a finger gripper, an alternative syringe assembly, particularly an improved syringe assembly, an alternative kit comprising components of a syringe assembly, particularly an improved kit, and an alternative method for a syringe assembly or kit, particularly an improved method.

Summary of the Invention

The object of the present invention is a plunger for a syringe assembly, a method for manufacturing such a plunger, a finger gripper for a syringe assembly, a method for manufacturing such a finger gripper, a syringe assembly, a kit including components of a syringe assembly, and a method of using a syringe assembly or kit, each defined in accordance with the respective independent claims.

A first aspect of the invention relates to a plunger for a syringe assembly for administering a liquid composition, wherein the plunger includes a plunger rod and a plunger head. The plunger rod includes a proximal end and a distal end, wherein the plunger head is attached to the proximal end of the plunger rod. The plunger head includes a proximal-facing surface configured to act as a thumbplate during administration. According to the invention, the plunger includes a gripping pad attached to the proximal-facing surface of the plunger head, wherein the gripping pad extends at least partially onto the proximal-facing surface and is formed by injection molding.

A second aspect of the invention relates to a method for manufacturing a specified plunger, wherein the method comprises at least the following steps:

- Manufacturing, especially at least manufacturing the plunger head, and

- The gripping pad is formed by injection molding.

A third aspect of the invention relates to a finger gripper for a syringe assembly for administering a liquid composition, wherein the finger gripper includes a finger gripper body having two flanges extending radially in opposite directions from a central bore of the finger gripper body, through which a plunger of the syringe assembly can be inserted. Each flange acts as a gripping portion and has a finger contact area on which at least one of the user's fingers can be partially placed during administration to support the finger. Furthermore, each flange includes a proximal-facing surface and a distal-facing surface. According to the invention, the finger gripper includes a gripping pad attached to the distal-facing surface of at least one of the flanges, wherein the gripping pad extends at least partially onto the distal-facing surface and is formed by injection molding.

A fourth aspect of the present invention relates to a method for manufacturing a specified finger gripper, wherein the method comprises at least the following steps:

- Manufacture a finger gripper body comprising two flanges extending radially in opposite directions from a central hole in the finger gripper body, through which a plunger of an syringe assembly can be inserted. Each flange acts as a gripping portion and has a finger contact area on which at least one of a user's fingers can be partially placed during application to support the finger during application. Each flange includes a proximal surface and a distal surface.

- The gripping pad is formed by injection molding.

A fifth aspect of the invention relates to a syringe assembly for administering a liquid composition to a human or animal body, comprising at least a longitudinal syringe barrel having an inner cavity for receiving and storing the liquid composition to be administered, a finger gripper coupled to a proximal end of said barrel, and a plunger having a plunger rod and a plunger head, the distal end of the plunger rod being at least partially disposed within the inner cavity of the barrel. According to the invention, the plunger is a plunger according to the invention or a plunger made according to the method of the invention, and/or the finger gripper is a finger gripper according to the invention or a finger gripper made according to the method of the invention.

A sixth aspect of the invention relates to a kit comprising several components for a syringe assembly according to the invention, wherein the components are configured to be assembled into such a syringe assembly. The kit includes at least a longitudinal syringe barrel having an inner cavity for receiving a liquid composition to be administered, a finger gripper configured to be coupled to a proximal end of the barrel, and a plunger having a plunger rod and a plunger head, the distal end of the plunger rod being configured to be at least partially disposed within the inner cavity of the barrel. According to the invention, the plunger is a plunger according to the invention or a plunger made according to the method of the invention, and/or the finger gripper is a finger gripper according to the invention or a finger gripper made according to the method of the invention.

The seventh aspect of the invention relates to the use of a syringe assembly or kit according to the invention for cosmetic or therapeutic applications, particularly for replacing or filling biological tissue or increasing the volume of biological tissue, wherein an effective amount of the liquid composition, particularly an effective amount of the dermal filler composition, is applied to a subject.

This invention allows for the provision of syringe assemblies that are very easy, comfortable, and safe to use for administering liquid compositions, particularly for injecting dermal fillers, especially for administering hyaluronic acid dermal fillers. It also allows for the provision of kits that are very easy, comfortable, and safe to use, wherein the kits include components for the syringe assembly, and wherein the syringe assembly and/or kits, as well as the individual components of the kits and/or syringe assembly, are easy to manufacture and can be well stored and handled by practitioners.

A plunger with a reduced slippage plunger head and a comfortable finger contact area can be provided, along with a plunger with a reduced slippage finger gripper and a comfortable finger contact area, through a gripping pad attached to the proximal surface of the plunger head and/or through a gripping pad attached to the distal surface of one of the flanges of the finger gripper body. Therefore, syringe assemblies or kits can be provided for more comfortable, precise, and safer use. Reduced finger slippage results in more controlled use, especially in the injection of highly viscous fluids, such as the injection or application of dermal fillers, particularly hyaluronic acid dermal fillers, which requires high squeezing force.

Possible and particularly preferred embodiments of the object of the invention are set forth in the dependent claims. Further embodiments and other objects, advantages and features of the invention will become apparent from the following detailed description of the invention, the description of particular embodiments in the accompanying drawings, and the detailed description of the embodiments. The terminology of the original claims is incorporated herein by explicit reference.

Detailed description of the invention

According to a first aspect of the invention, a plunger of a syringe assembly for administering a liquid composition includes a plunger rod and a plunger head, wherein the plunger rod includes a proximal end and a distal end, and wherein the plunger head is attached to the proximal end of the plunger rod and includes a proximal-facing surface configured to act as a thumbplate during administration. According to the invention, the plunger further includes a gripping pad attached to the proximal-facing surface of the plunger head, wherein the gripping pad extends at least partially onto the proximal-facing surface and is formed by injection molding.

A gripping pad attached to the proximal surface of the plunger head provides a plunger head with reduced slippage and a comfortable finger contact area. This allows for a more comfortable, precise, and safer syringe assembly, including the plunger. The reduced finger slippage achieved by the gripping pad significantly improves safety during use, especially during injection. The gripping pad allows for better grip, resulting in more controlled use, particularly when the plunger is used in a syringe assembly for injecting highly viscous fluids, such as for injecting or applying dermal fillers, especially hyaluronic acid dermal fillers, which requires high squeezing forces. Using injection molding to manufacture the gripping pad for the plunger head makes its production very easy and economical.

As used herein, the term "syringe assembly" generally refers to an application device, particularly an injection device, configured for discharging, preferably administering, and especially for injecting at least one component received and stored in the device. The term "syringe assembly" specifically includes application devices for discharging single-component, two-component, or multi-component contents, particularly injection devices, especially devices for discharging single-component, two-component, or multi-component materials. The term "syringe assembly" as used herein specifically refers to a syringe or syringe-like application device configured for discharging or administering at least one component stored in the device. The term "syringe assembly" as used herein also specifically refers to a device operating as a manually operated reciprocating pump, typically comprising a syringe barrel and a plunger having an inner cavity or chamber for receiving and storing at least one component to be administered, wherein the plunger can be pulled and pushed along the longitudinal axis of the inner cavity or chamber, particularly allowing fluid to be drawn in and expelled separately through a discharge port at the proximal end of the inner cavity or chamber at the proximal end of the syringe barrel.

Within the scope of use of the syringe assembly and/or kit according to the invention, the term "injection" may refer to intradermal, intradermal, or subcutaneous injection or subcutaneous tissue injection.

The term "composition" as used herein is not particularly limited and can be, for example, a liquid composition. Preferably, the composition can be a composition used as or suitable for use as a soft tissue filler, particularly a dermal filler.

As used herein, the term "liquid composition" should be understood to include fluids (such as aqueous liquids), solutions (such as aqueous solutions), suspensions (such as aqueous suspensions), dispersions (such as aqueous dispersions), emulsions (such as aqueous emulsions), gels (such as hydrogels), and mixtures thereof.

As used herein, the term "multi-component contents" refers to a contents or composition containing at least two (different) ingredients, particularly more than two (different) ingredients, which must be mixed into a mixture before application. Thus, a single-component composition is a ready-to-use composition, and a two-component composition is a composition having two components that must be mixed before application.

As used herein, the term "plunger" refers to a component or assembly of several components made as a single piece, configured in a syringe assembly to apply pressure to contents (e.g., a liquid composition) received and stored in the cavity or chamber of a syringe barrel, wherein the contents can be expelled from the cavity of the syringe barrel by the plunger when sufficient pressure is applied in the longitudinal direction to move the plunger longitudinally along the longitudinal axis of the syringe barrel within the cavity of the syringe barrel.

As used herein, the term "plunger rod" or "push rod" specifically refers to a longitudinal, preferably rod-like portion configured to at least partially insert its distal end into the lumen or chamber of a syringe barrel.

As used herein, the term "plunger head" refers to a component attached to the proximal end of the plunger rod that acts as a thumb plate during application. In this regard, the plunger head specifically includes a substantially flat, proximal-facing surface, which is preferably configured to support the physician's thumb during use, particularly during the application of the squeezing force required to dispense the contents received and stored in the lumen or chamber of the syringe barrel.

In possible, particularly preferred, embodiments of the plunger according to the invention, the plunger head may include or may be a component that is substantially plate-shaped or substantially disc-shaped.

In a possible, particularly preferred, embodiment of the plunger according to the invention, the plunger head can be integrally manufactured with the plunger rod, particularly by injection molding.

In an alternative embodiment of the plunger according to the invention, the plunger head may be connected to the plunger rod, for example by a snap-fit connection, particularly by a detachable snap-fit connection, or by other mounting mechanisms.

In a possible, particularly preferred, embodiment of the plunger according to the invention, the plunger may be configured for use with a syringe assembly comprising a syringe barrel configured to receive and store 2 ml or less of the composition to be administered, wherein the plunger may be particularly configured for use with the syringe barrel configured to receive and store 1 ml or less (e.g., 0.5 ml) of the composition, particularly a liquid composition of a dermal filler (e.g., hyaluronic acid dermal filler).

In a possible, particularly preferred, embodiment of the plunger according to the invention, the plunger may be additionally configured to dispense or expel from the cavity a composition received and stored in the cavity of a syringe barrel, wherein the cavity of the syringe barrel is defined by a cylindrical chamber having a smaller inner diameter and/or a larger dimension in the longitudinal direction compared to the cavity size of a 1 ml syringe barrel according to ISO 11040-6.

In a possible, particularly preferred, embodiment of the plunger according to the invention, the gripping pad on the plunger head is made of thermoplastic elastomer (TPE), particularly colored thermoplastic elastomer (cTPE). Using an injection-molded TPE gripping pad allows for more comfortable, precise, and safer use, and prevents the user's thumb from slipping during use. The TPE as the gripping pad material is easily applied to the proximal surface of the plunger head and allows for good adhesion to the proximal surface of the plunger head.

To achieve the advantageous effect of providing a favorable plunger, the plunger head can be made of polypropylene (PP), particularly by injection molding. Preferably, the plunger rod is also made of polypropylene, particularly by injection molding, and preferably integrally formed with the plunger head. This means that, in one embodiment of the plunger according to the invention, the plunger is formed by 2K injection molding, wherein preferably, the plunger rod and plunger head are each made of the same first injection-molded material, particularly polypropylene (PP), preferably integrally formed, wherein the gripping pad is made of a second material, particularly TPE, by injection molding.

Preferably, the gripping pad is applied directly to the proximal surface of the plunger head during manufacturing. Alternatively, this means that in another embodiment, the gripping pad may be manufactured separately from the plunger and thus from the plunger head, and then attached to the proximal surface of the plunger head.

In another embodiment of the plunger according to the invention, the plunger rod and/or plunger head may be made of materials other than PP, particularly of another suitable plastic. However, the material used to make the plunger particularly has properties similar to PP.

Grip pads can also be made of other materials, particularly other suitable plastics, instead of TPE. However, the preferred grip pad material is a rubber-like material or another material that generates high friction, which also prevents the user's thumb from slipping and provides comfortable, precise, and safe use.

Using 2K injection molding to manufacture plungers allows for good adhesion between the gripping pads on the proximal surface of the plunger head, and makes plunger manufacturing easier and more advantageous.

In one embodiment of the invention, the grip pad can be at least partially colored, particularly fully colored, wherein the grip pad can be made of a colored material, such as colored TPE as described above. This can be achieved, for example, by adding colored particles to the injection molding raw material. Using a plunger with a colored grip pad allows for the provision of multiple syringe assemblies or kits, each pre-filled with a (different) composition for administration, wherein each composition or content is preferably associated with a specific color by which the syringe assembly and/or kit can be distinguished. This helps physicians to distinguish different products at first glance and thus differentiate different syringe assemblies or kits pre-filled with different compositions for different purposes. Therefore, colored grip pads greatly contribute to improved usability and safety. In particular, the risk of confusion between syringe assemblies or kits can be controlled because colored grip pads are more visually detectable than any hints or indications in the accompanying instructions for use. Thus, with colored grip pads, the risk of misadministration, particularly the risk of confusion between compositions to be administered, can be reduced in a comfortable and simple manner.

To ensure good adhesion of the gripping pad to the proximal surface of the plunger head, in one embodiment of the invention, the plunger head can be manufactured using an injection molding tool having a surface shaped by the surface of the injection molding tool, and said surface has been etched to produce a tool surface roughness in the range of VDI 3400 Ref. 21 to VDI 3400 Ref. 30, i.e., a roughness between Ra = 1.12 μm and Ra = 3.15 μm, wherein Rmax is in the range of 4.5 μm to 12.5 μm, wherein in particular the tool surface has been etched such that the surface roughness reaches the roughness according to VDI 3400 Ref. 27, characterized by Ra = 2.25 μm and Rmax = 9.0 μm.

To further improve the adhesion of the gripping pad to the proximal surface of the plunger head, in one embodiment of the plunger according to the invention, the proximal surface of the plunger head may include at least one deepened portion, particularly at least one groove, wherein the at least one deepened portion is filled with gripping pad injection molding material when the gripping pad is attached to the proximal surface of the plunger head. This deepened portion allows for a larger contact area between the proximal surface and the gripping pad material, thereby resulting in better adhesion and bonding between the plunger head material and the gripping pad material.

Preferably, the depth of at least one deepened portion in the direction perpendicular to the surface facing the proximal side is between 0.5 mm and 2 mm, preferably about 1 mm.

In a very advantageous embodiment of the plunger according to the invention, the proximal surface of the plunger head may include two such deepened portions or grooves, particularly concentrically arranged circular grooves, preferably whose centers are aligned with the longitudinal axis of the plunger.

For a comfortable and safe grip, especially for comfortable and safe contact with the user's thumb, the average thickness of the grip pad, particularly in the area outside the grooves and/or deepened portions, is preferably in the range of 0.1 mm to 0.5 mm, particularly about 0.2 mm.

In one embodiment of the plunger according to the invention, the gripping pad on the plunger head is designed such that it represents a symbol, particularly preferably a letter or another character selected from ASCII codes. Therefore, in particular, in addition to or as an alternative to a colored gripping pad, a plunger with visually detectable distinguishing features can be provided in a very easy manner. This helps physicians distinguish different products at first glance, different syringe components or kits pre-filled with different compositions for different uses. This greatly contributes to improved usability and safety. In particular, since the conformation in the gripping pad is more visually detectable than any prompts or indications in the accompanying instructions for use, the risk of confusing syringe components or kits can be controlled. Thus, with such a gripping pad, the risk of misapplication, particularly the risk of confusing the composition to be applied, can be reduced in a comfortable and simple manner.

For example, the grip pad may be designed to represent one of the following symbols: "+", "-", "L", or a similar symbol. For example, "+" or "L" may indicate that the composition to be administered and received and stored in the lumen of the syringe barrel of the syringe assembly or kit contains a defined active ingredient, such as an anesthetic like lidocaine. For example, "-" may indicate that the composition included in the syringe assembly or kit does not contain that composition or the defined active ingredient.

In one embodiment of the plunger according to the invention, the symbol can be represented by an area that is not filled or covered by the gripping pad injection material, but is at least partially surrounded by the gripping pad injection material. This means that the symbol can be visualized by a concave representation.

Alternatively, and possibly more advantageously in some cases, the symbol can be represented by an area filled or covered with gripping pad injection material, said area being at least partially or completely surrounded by a blank area. This means that, in this case, the symbol is visualized using a convex representation.

In a possible, particularly preferred, embodiment of the plunger according to the invention, the gripping pad attached to the plunger head is manufactured as a single piece by injection molding, specifically comprising only a single injection point. Therefore, very easy manufacturing can be achieved using only a single injection molding step for producing the gripping pad. This allows for rapid, simple, and reproducible manufacturing of the gripping pad.

In one embodiment of the plunger according to the invention, the plunger comprises only a gripping pad, preferably integrally formed by injection molding, wherein, particularly for forming the gripping pad, the injection molding material for the gripping pad has been applied directly to the proximal surface of the plunger head. Therefore, very easy manufacturing can be achieved using only a single injection molding step for generating the gripping pad. This allows for the rapid and simple reproduction of the gripping pad.

In one embodiment of the plunger according to the invention, at least one injection point for the grip pad material is located near the outer periphery of the grip pad, particularly at the outer third of the grip pad diameter, or at the outer third of the distance from the center of the grip pad to the outer periphery of the grip pad, especially if the grip pad is made as a single piece, comprising only one injection point. This results in a very uniform distribution of the injection-molded material, particularly when the proximal surface of the plunger head has a slightly concave shape to provide a more economical contact area for the user's thumb.

In one embodiment of the plunger according to the invention, at its distal end, the plunger rod can be further configured to receive a piston, wherein, in particular, the distal end of the plunger rod can be configured to be connected to the piston via a snap-fit connection. Thus, a plunger can be provided onto which the piston can be easily and space-savingly mounted. This space-saving design is particularly necessary for use with syringe barrels having small inner diameters.

To achieve an advantageous snap-fit connection between the distal end of the plunger rod and the piston, particularly the proximal end, the plunger rod can have a truncated conical tip or a mushroom-shaped tip, etc. Furthermore, the plunger rod can have a piston receiving portion arranged proximally adjacent to the tip, the diameter of which is smaller than that of the tip. For this advantageous snap-fit connection, the piston can be made of a suitable, biocompatible, elastic material, or at least partially contain such a material. The geometry of the plunger rod tip, with its truncated conical or mushroom-shaped tip, allows for virtually error-free assembly of the piston and distal end of the plunger rod without applying torque to the plunger rod, while simultaneously establishing a robust and secure connection. Moreover, this geometry is easier to manufacture and saves space compared to a threaded connection between the distal end of the plunger rod and the piston.

In order to axially fix the piston at the distal end of the plunger rod and transmit the applied compressive force, the plunger rod may include a radially extending plate that acts as a stop in the proximal direction at the proximal end of the plunger receiving portion.

In one embodiment of the plunger according to the invention, the plunger, particularly the plunger rod, can be configured to withstand high extrusion pressure, since such extrusion pressure occurs during the injection of, for example, a highly viscous fluid, such as during the injection of dermal fillers like hyaluronic acid dermal fillers.

To ensure sufficient mechanical strength, particularly adequate kink stability, of the plunger, especially the plunger rod—meaning sufficient resistance to kinking, especially when the plunger is configured for use with a 1 ml syringe conforming to ISO 11040-6 or with a syringe with a smaller inner diameter, such as a 1 ml standard syringe, the plunger rod may include at least one portion along its longitudinal direction that is at least substantially a double-T profile shape, a similar double-T profile shape, an I profile shape, a similar I profile shape, etc. To further enhance mechanical strength, the plunger rod may have at least one portion in its longitudinal direction having a double mushroom-shaped profile, a similar mushroom-shaped profile, or a combination of mushroom-T profiles, etc., particularly with a convex or curved external geometry. In some cases, it is advantageous if the plunger rod has a prescribed shape along its entire length. Good mechanical strength of the plunger, especially the plunger rod, makes the plunger suitable for injecting and applying highly viscous fluids, such as dermal fillers like hyaluronic acid dermal fillers. Higher mechanical strength reduces the probability of mechanical failure, thereby improving safety.

To achieve high kinetic stability and high mechanical strength in the plunger rod, a large-area cross-section of the plunger rod may be more advantageous in certain cases, particularly an elliptical, circular, or square cross-section. This large-area, particularly elliptical, circular, or square cross-section, may extend only over a portion of the plunger rod's length, over several portions in the longitudinal direction, or may extend over the entire length of the plunger rod. The geometry and/or size of the cross-sectional region of the plunger rod, particularly the diameter, may be constant or variable along the length of the plunger rod. However, a constant geometry and/or size of the cross-sectional region in the longitudinal direction of the plunger rod is preferred within at least one portion of the plunger rod. The geometry and/or size of the cross-sectional region, particularly the diameter of the cross-sectional region of the plunger rod, may differ between several portions of the plunger rod or may be the same along the entire length of the plunger rod. In one embodiment, the geometry and/or size of the cross-sectional region of the plunger rod may be constant over at least 50%, 60%, 70%, 80%, 90%, or 95% of the entire length of the plunger rod. Therefore, advantageous mechanical properties can be achieved in certain situations. This further simplifies the manufacture of the plunger rod. In some cases, it also allows the use of a different pushrod material, and in others, a more advantageous pushrod material.

A second aspect of the invention is a method for manufacturing the aforementioned plunger, wherein, according to the invention, the method for manufacturing such a plunger comprises at least the following steps: manufacturing, particularly at least manufacturing a plunger head, and forming a gripping pad by injection molding.

In one embodiment of the method for manufacturing the plunger according to the invention, the plunger head can also be made by injection molding, particularly integrally formed with the plunger rod, wherein the plunger head and/or plunger rod are preferably made of polypropylene (PP), particularly integrally formed.

Alternatively, the plunger head and/or plunger rod can be made separately and/or from different materials, wherein the plunger rod and plunger head are in particular each made from a material having properties similar to PP.

In one embodiment, particularly in a preferred embodiment of the method for manufacturing the plunger according to the invention, the gripping pad is formed by directly applying a gripping pad injection molding material to the proximal surface of the plunger head, wherein the gripping pad is particularly made as a single piece, preferably with only one injection point, which is particularly located at the outer third of the radial direction of the gripping pad.

A third aspect of the invention relates to a finger gripper for an injector assembly for administering a liquid composition, wherein the finger gripper according to the invention comprises a finger gripper body having two flanges or wings extending radially in opposite directions from a central hole in the finger gripper body, wherein a plunger of the injector assembly, particularly a plunger according to the invention, can be inserted through the central hole. Each flange is configured to act as a gripping portion and has a finger contact area on which at least one of a user's fingers can be partially placed during administration to support the finger during administration, wherein each flange includes a proximal surface and a distal surface. According to the invention, the finger gripper includes a gripping pad attached to the distal surface of at least one of the flanges or wings of the finger gripper body, wherein the gripping pad extends at least partially onto the distal surface and is formed by injection molding.

A gripping pad attached to the distal surface of a finger gripper provides a comfortable finger contact area with reduced slippage. This allows for more comfortable, precise, and safer use of syringe assemblies incorporating finger grippers. The reduced finger slippage achieved by the gripping pad significantly improves safety during use, particularly during injection. The improved grip allows for more controlled use, especially when the finger gripper is used in syringe assemblies for injecting highly viscous fluids, such as dermal fillers, particularly hyaluronic acid dermal fillers, which require high extrusion pressure. Injection molding is used to manufacture the gripping pad for the finger gripper, making its production very easy and economical.

As used herein, the term "finger gripper" refers to a handle and thus a gripping device configured to be gripped at least partially by the user's fingers, particularly the fingers of a physician, for use in a syringe assembly to support at least the first and second fingers during administration.

The finger gripper is specifically configured to be preferably detachably connected to the syringe barrel, particularly to the proximal end of the syringe barrel, so as to allow for comfortable gripping of the syringe barrel to administer the composition received and stored within the inner cavity of the syringe barrel.

To facilitate connection with the syringe barrel, the finger gripper, particularly the finger gripper body, may include a groove into which the proximal flange of the syringe barrel may be laterally inserted, as disclosed, for example, in WO 2017/176476 A1 or a similar document.

The central hole of the finger gripper body can be partially open along its periphery or completely closed in the circumferential direction. A circumferentially open central hole allows for pre-assembly of the syringe barrel and plunger, i.e., the plunger is at least partially inserted into the inner cavity of the barrel, before the finger gripper body and syringe barrel are joined and the plunger is inserted laterally into the central hole. A completely closed circumferential central hole requires the plunger to be inserted after the syringe barrel and finger gripper body are joined, wherein the plunger must be inserted along the longitudinal axis of the syringe barrel and perpendicular to the diameter of the central hole.

Preferably, the finger gripper, and particularly the two flanges of the finger gripper, are configured so that each is gripped by a finger. For ergonomic gripping, at least one flange is curved, preferably having a recessed proximal side and a convex distal side. Preferably, one of the flanges or wings is configured for gripping with the user's index finger, and the other flange or wing is configured for gripping with the user's middle finger.

In a possible, particularly preferred, embodiment of the finger gripper according to the invention, the finger gripper can be configured for use with a syringe assembly comprising a syringe barrel configured to receive and store 2 ml or less of the composition to be administered, wherein the finger gripper can be particularly configured for use with, particularly coupled to, the syringe barrel configured to receive and store 1 ml or less (e.g., 0.5 ml) of the composition, particularly a liquid composition of a dermal filler (e.g., hyaluronic acid dermal filler).

In one embodiment of the finger gripper according to the invention, at least one gripping pad of the finger gripper is made by applying gripping pad injection molding material directly to the distally facing surface of the corresponding flange. Alternatively, this means that in another embodiment, the gripping pad may also be made separately from the finger gripper and thus from the finger gripper body, and then attached to the distally facing surface of the corresponding flange or wing of the finger gripper.

In one embodiment of the finger gripper according to the invention, at least one gripping pad of the finger gripper is made of thermoplastic elastomer (TPE), particularly colored thermoplastic elastomer (cTPE).

Using injection-molded TPE grip pads enables more comfortable, precise, and safer use, and prevents the user's fingers from slipping during use. TPE, as the grip pad material, is easily applied to the distal surface of the finger grip flange and achieves good adhesion to the flange surface.

To achieve a favorable effect or provide a favorable finger grip, the finger grip body can be made of polypropylene (PP), particularly by injection molding. This means that, in one embodiment of the finger grip according to the invention, the finger grip is made by 2K injection molding, wherein preferably, the finger grip body including the flange is made of a first injection molding material, particularly polypropylene (PP), preferably as a single piece, and the grip pad is made of a second material, particularly TPE, by injection molding.

In another embodiment of the finger gripper according to the invention, the finger gripper, particularly the finger gripper body, can be made of materials other than PP, especially another suitable plastic material. However, the material used to make the finger gripper particularly has properties similar to PP.

Grip pads can also be made of other materials, particularly other suitable plastics, instead of TPE. However, the preferred grip pad material is a rubber-like material or another material that generates high friction, which also prevents the user's fingers from slipping and provides comfortable, precise, and safe use.

By using 2K injection molding to manufacture finger grippers, good adhesion between gripping pads on at least one distally facing surface of the finger gripper body can be achieved, and the manufacture of finger grippers becomes easy and advantageous.

In one embodiment of the invention, the gripping pad attached to the body of the finger gripper can be at least partially colored, and particularly fully colored, wherein the gripping pad can be made of a colored material, such as colored TPE as described above. This can be achieved, for example, by adding colored particles to the injection molding raw material. Using a finger gripper with a colored gripping pad allows for the provision of multiple syringe assemblies or kits, each pre-filled with a (different) composition for administration, wherein a specific color is preferably associated with each composition or content, by which the syringe assembly and/or kit can be distinguished. This helps physicians to distinguish different products at first glance, and to differentiate between different syringe assemblies or kits pre-filled with different compositions for different purposes. Therefore, colored gripping pads greatly contribute to improved usability and safety. In particular, the risk of confusion between syringe assemblies or kits can be controlled because colored gripping pads are more visually detectable than any prompts or instructions in the accompanying user manual. Thus, with colored gripping pads, the risk of misadministration, particularly the risk of confusion between compositions to be administered, can be reduced in a comfortable and simple manner.

To ensure good adhesion of the grip pad to at least one of the distal-facing surfaces of the finger gripper body, in one embodiment of the invention, the finger gripper body can be manufactured using an injection molding tool having a surface through which the distal-facing surface of the finger gripper body is shaped, wherein the tool surface has been etched to produce a tool surface roughness in the range of VDI 3400Ref.21 to VDI3400Ref.30, i.e., a roughness between Ra = 1.12 μm and Ra = 3.15 μm, wherein Rmax is in the range of 4.5 μm to 12.5 μm, wherein in particular the tool surface has been etched to produce a surface roughness reaching the roughness of VDI 3400Ref.27, characterized by Ra = 2.25 μm and Rmax = 9.0 μm.

To further improve the adhesion of the grip pad to at least one of the distal-facing surfaces of the finger gripper body, in one embodiment of the finger gripper according to the invention, at least one of the distal-facing surfaces of the finger gripper body may include at least one deepened portion, particularly at least one groove, wherein the at least one deepened portion is filled with a grip pad injection-molded material when the grip pad is attached to said surface of the finger gripper body. This deepened portion allows for a larger contact area between the distal-facing surface and the grip pad material, thereby resulting in better adhesion and bonding between the finger gripper body material and the grip pad material.

Preferably, the depth of at least one deepened portion in the direction perpendicular to the surface facing the distal side is between 0.5 mm and 2 mm, preferably about 1 mm.

For comfortable and safe gripping, especially for comfortable and safe contact with the user's fingers, the average thickness of at least one gripping pad of the finger gripper, particularly in the area outside the groove and/or deepened portion, is preferably in the range of 0.1 mm to 0.5 mm, particularly about 0.2 mm.

In one embodiment of the finger gripper according to the invention, the gripping pad on the finger gripper is designed such that at least one area of the distal-facing surface of the finger gripper that is not filled or covered by the gripping pad injection molding material is completely surrounded by the injection molding material.

In a preferred embodiment of the finger gripper according to the invention, the area not filled or covered by the gripper pad injection molding material includes one or more stripes, particularly at least two parallel stripes, which preferably extend in the longitudinal and transverse directions of the respective flange or wing of the finger gripper, respectively.

The gripping pad on the finger gripper can alternatively be designed to represent a symbol, particularly preferably a letter selected from ASCII code or another character. Therefore, in particular, or as an alternative to a colored gripping pad, a finger gripper with visually detectable distinguishing features can be provided very easily. This helps physicians distinguish different products at first glance, different syringe components or kits pre-filled with different compositions for different purposes. This greatly contributes to improved usability and safety. In particular, since the conformation in the gripping pad is more visually detectable than any hints or indications in the accompanying instructions for use, the risk of confusing syringe components or kits can be controlled. Thus, with such a gripping pad, the risk of misapplication, especially the risk of confusing the composition to be applied, can be reduced in a comfortable and simple manner.

Additionally, the grip pads on the finger grips can be designed to represent one of the following symbols: "+", "-", "L", or a similar symbol.

In one embodiment of the finger gripper according to the invention, the symbol can be represented by an area that is not filled or covered with gripping pad injection-molded material, said area being at least partially surrounded by the gripping pad injection-molded material. This means that the symbol can be visualized by a concave representation.

Alternatively, and possibly more advantageously in some cases, the symbol can be represented by an area filled with injection-molded gripping pad material, said area being at least partially or completely surrounded by a blank area. This means that, in this case, the symbol is visualized using a convex representation.

In a possible, particularly preferred, embodiment of the finger gripper according to the invention, the gripping pad attached to the body of the finger gripper is manufactured as a single piece by injection molding, specifically comprising only a single injection point. Therefore, manufacturing can be achieved very easily using only a single injection molding step for producing the gripping pad. This allows for rapid and simple replication of the gripping pad's manufacturing process.

In one embodiment of the finger gripper according to the invention, each flange of the finger gripper body includes only one gripping pad, preferably integrally formed by injection molding, wherein, particularly for forming the gripping pad, the injection molding material for the gripping pad has been applied directly to the distally facing surface of the flange. Therefore, very easy manufacturing can be achieved using only a single injection molding step for generating the gripping pad. This allows for rapid and simple replication of the gripping pad's manufacturing.

In one embodiment of the plunger according to the invention, at least one injection point for the gripping pad material is located near the outer periphery of the gripping pad, particularly at the outer third of the gripping pad diameter, or at the outer third of the distance from the center of the gripping pad to the outer periphery of the gripping pad, especially if the gripping pad is made as a single piece, comprising only one injection point. This results in a very uniform distribution of the injection-molded material.

A fourth aspect of the present invention relates to a method for manufacturing the aforementioned finger gripper, wherein, according to the present invention, the method for manufacturing such a finger gripper includes at least the following steps:

- Manufacture a finger gripper body comprising two flanges or wings extending radially in opposite directions from a central hole in the finger gripper body, through which a plunger of an syringe assembly can be inserted, and wherein each flange acts as a gripping portion and has a finger contact area on which at least one of a user's fingers can be partially placed during application to support the finger during application, and wherein each flange includes a proximal surface and a distal surface, and

- The gripping pad is formed by injection molding.

In one embodiment, particularly in a preferred embodiment, the finger gripper is also made of plastic, particularly polypropylene, and is also made by injection molding. Preferably, the finger gripper is made entirely by 2K injection molding, wherein the finger gripper body is preferably made of a first injection molding material, and the gripping pad is made of a second injection molding material, particularly TPE.

In one embodiment, particularly in a preferred embodiment of the method for manufacturing a finger gripper according to the invention, the gripper pad is formed by directly applying a gripper pad injection molding material to at least one of the distally facing surfaces of the finger gripper body, wherein the gripper pad is made in particular as a single piece, preferably with only one injection point, which is particularly located at the outer third of the radial or lateral direction of the gripper pad.

A fifth aspect of the invention relates to a syringe assembly for administering a liquid composition to a human or animal body, i.e., to any subject, comprising at least a longitudinal syringe barrel having an inner cavity for receiving and storing the liquid composition to be administered, a finger gripper coupled to a proximal end of said barrel, and a plunger having a plunger rod and a plunger head, wherein the plunger rod is at least partially disposed within the inner cavity at the distal end of the barrel. The syringe assembly according to the fifth aspect of the invention is characterized in that the plunger is a plunger according to the invention or a plunger made according to the method of the invention, and/or the finger gripper is a finger gripper according to the invention and/or a finger gripper made according to the method of the invention.

Generally, the syringe assembly can be an assembly for administering a single-component liquid composition or a two-component or multi-component liquid composition. However, in a preferred embodiment, the syringe assembly is configured for administering a single-component ready-to-use mixed composition.

In one embodiment of the invention, the syringe barrel of the syringe assembly is made of plastic, particularly of cyclic olefin copolymers (COC). Using a syringe barrel made of plastic reduces the risk of needle ejection during administration, especially during the spraying or injection of highly viscous fluids (such as dermal fillers), because a better syringe-needle connection can be established compared to a barrel made of glass.

Furthermore, using plastic for the syringe barrel allows for the provision of syringe barrels with Luer lock connectors integrally manufactured with the barrel. Therefore, the risk of needle ejection and/or disconnection between the needle assembly or cannula and the syringe barrel can be reduced. Additionally, plastic syringe barrels can be easily manufactured via injection molding, resulting in smaller manufacturing tolerances, thus leading to a more reliable needle-syringe connection and less pressure during injection of contents stored within the syringe barrel's cavity. Moreover, better geometric precision can be achieved in the syringe barrel, resulting in a more precise, robust, and secure connection between the finger gripper and plunger and the syringe barrel. Furthermore, the risk of failure of the syringe barrel flange is reduced in plastic syringes compared to glass syringes.

The inner surface of the syringe barrel can be siliconized. Therefore, the extrusion pressure can be reduced.

In one embodiment of the invention, the syringe barrel of the syringe assembly according to the invention may have an inner cavity for receiving and storing a volume of 2 ml or less of the composition to be administered, wherein the syringe barrel may be specifically configured to receive and store 1 ml or less (e.g. 0.5 ml) of the composition, particularly liquid compositions of dermal fillers (e.g., hyaluronic acid dermal fillers).

The inner diameter of the syringe barrel can be smaller than, for example, the inner diameter of a standard syringe barrel conforming to ISO 11040-6, and is preferably longer, with a diameter/length ratio preferably about 5/70. A longer inner diameter of the syringe barrel has the advantage of lower extrusion pressure compared to syringe barrels conforming to ISO 11040-6. This makes it simpler, more controllable, and safer to use. Additionally, the extruded volume can be better controlled, with less product ejected per milliliter of plunger movement in the longitudinal direction during injection.

The syringe assembly according to the invention provides a very simple, comfortable and safe syringe assembly for administering liquid compositions, particularly for injecting dermal fillers, especially hyaluronic acid dermal fillers, wherein the syringe assembly and its individual components are easy to manufacture, can store the liquid composition to be administered well, and are easy to handle by a physician.

The advantage of siliconizing the inner surface of the barrel is that by keeping free silicon to a minimum, a good lubricating layer can be applied to the inner surface of the barrel, preventing interaction with the skin filler. Therefore, siliconizing the inner barrel surface allows for lower extrusion forces, making it simpler, more controllable, and safer to use. Lower extrusion forces also help reduce the risk of mechanical failure.

Grip pads and/or symbols integrated into them improve usability and security due to their easy visual recognition. Good finger contact is achieved through the use of TPE grip pads, enabling controlled and safer application. Visual recognition can be further improved through colored grip pads.

In one embodiment of the syringe assembly according to the invention, the syringe barrel includes a Luer lock connector at its distal end, the connector being integrally formed with the syringe barrel. Furthermore, the syringe assembly may include a tip cap that covers and seals the distal end of the syringe barrel. Compared to a Luer cone connector, the Luer lock connector offers the advantage of establishing a more secure and locked connection, which is also releaseable.

Luer connections and Luer connectors are generally known and standardized in the prior art, with Luer connections typically including convex Luer connectors and corresponding concave Luer connectors. Luer lock connections are described, for example, in DIN EN ISO 80369-7:2017-10. They are characterized by a specific 6% taper, and Luer lock connections also include threaded connections.

The tip cap can be a two-part tip cap comprising a rigid component and a resilient component, wherein the maximum outer diameter of the rigid component is preferably less than or equal to the outer diameter of the Luer lock connector of the syringe barrel. Therefore, the assembly, storage, unpacking, and use of pre-filled syringe assemblies can be safer, as this reduces the risk of the tip cap getting stuck and being accidentally removed or damaged.

In one embodiment, the rigid member may include an external thread and may be screwed into and engage with the internal thread of the Luer lock connector of the syringe barrel, wherein the resilient member of the tip cap may be inserted into the rigid member and attached to the Luer cone of the Luer lock connector, thereby sealing the outlet passage of the syringe barrel.

A sixth aspect of the invention relates to a kit comprising components of a syringe assembly according to the invention, said components being configured to assemble into a syringe assembly according to the invention and as described above, wherein the kit comprises at least a longitudinal syringe barrel having an inner cavity for receiving and storing a liquid composition to be administered, a finger gripper configured to engage with a proximal end of said barrel, and a plunger having a plunger rod and a plunger head, the distal end of said plunger rod being configured to be at least partially disposed within the inner cavity of said barrel. The kit according to the invention is characterized in that the plunger is a plunger according to the invention or a plunger made according to the method of the invention, and/or the finger gripper is a finger gripper according to the invention or a finger gripper made according to the method of the invention, wherein, in particular, the plunger rod is configured to be inserted through a central hole in the body of the finger gripper.

The kit according to the invention provides a kit comprising a syringe assembly for the application of liquid compositions, particularly for the injection of dermal fillers, especially hyaluronic acid dermal fillers, which is very simple, comfortable and safe to use. The kit and its individual components are easy to manufacture, can store the liquid composition to be applied well, and are easy to handle by a physician.

In one embodiment of the kit and/or syringe assembly according to the invention, particularly in a preferred embodiment, the syringe barrel is pre-filled, particularly pre-filled with a liquid composition, especially pre-filled with a soft tissue filler material, such as one of the following soft tissue filler materials:

- Hyaluronic acid (HA)

-Carboxymethyl cellulose (CMC),

-Calcium hydroxyapatite in suspensions containing gel carriers such as CMC or HA collagen

- Another type of natural polysaccharide (alginate, heparin precursor, chitosan, etc.),

- Synthetic filler materials (e.g., polyethylene oxide, polylactic acid (PLLA), polymethyl methacrylate (PMA), polyacrylamide (PA), polyvinyl alcohol (PVA)) or

-Silicone for liquid injection.

Generally, filler materials like hyaluronic acid can be cross-linked and/or non-cross-linked. In addition, soft tissue fillers can contain additional substances such as vitamins, antioxidants, local anesthetics (e.g., lidocaine), hydroxyapatite particles, etc.

In particular, the syringe cartridge can be pre-filled with a filler material based on cross-linked hyaluronic acid (HA), especially 1,4-butanediol diglycidyl ether (BDDE)-cross-linked hyaluronic acid (HA) dermal filler.

There are no particular restrictions on its intended use. However, the most important use is for cosmetic purposes, such as treating skin texture.

This means that, generally speaking, the syringe assembly or kit according to the invention can be provided with an empty syringe barrel or with a pre-filled syringe barrel. However, in a preferred embodiment, the syringe assembly or kit according to the invention is provided with a pre-filled syringe barrel, particularly pre-filled with one of the aforementioned soft tissue filling materials.

As used herein, the term "soft tissue filler" broadly refers to a material designed to increase volume in areas of soft tissue deficiency. As used herein, "dermal filler" or "dermal filler composition" generally refers to a substance that increases, replaces, or expands volume under the skin, resulting in, for example, smoothing of wrinkles, enlargement of lips, improvement of skin appearance, or treatment of scars. Like soft tissue fillers, the dermal filler compositions of this invention are generally "injectable." Furthermore, dermal fillers are generally used in dermal areas, such as beneath the epidermis or above the subcutaneous tissue, and can therefore be injected subcutaneously, intradermally, or in combinations thereof.

Optionally, the kit may include instructions for use. For example, "instructions for use" could be instructions for cosmetic applications and/or the injection of soft tissue fillers (such as dermal fillers) into the human body, including replacing or filling biological tissue or increasing the volume of biological tissue for cosmetic purposes. In particular, the kit may include instructions for use as a soft tissue filler or dermal filler in cosmetic treatments.

The seventh aspect of the invention relates to the use of the syringe assembly or kit according to the invention, particularly for cosmetic or therapeutic applications, especially for replacing or filling biological tissue or increasing the volume of biological tissue, wherein an effective amount of a liquid composition, particularly an effective amount of a dermal filler composition, is to be applied to or administered to a subject by using the syringe assembly according to the invention and/or the kit according to the invention.

Generally, dermal filler compositions can be administered to a subject in an effective amount by injection, such as subcutaneous or intradermal injection. For example, the composition can be injected intradermally or subcutaneously using a continuous puncture technique, preferably at injection angles of minimum 1, 2, 3, 5, 8, 10, 12, 15, 20, 25, 30, 35, 40, or 45 degrees up to maximum 12, 15, 20, 25, 30, 35, 40, 45, 60, 75, or 90 degrees, wherein each of the aforementioned minimum values can be combined with any of the aforementioned maximum injection angles. This means that the injection angle can be, for example, in the range of 8 to 25 degrees, or in the range of 12 to 60 degrees, or in the range of 5 to 15 degrees, etc. As used herein, the term "injection angle" refers to the angle between the first longitudinal axis of the injection needle and the line projected by the needle onto the skin surface.

The injection effect can be improved by selecting an appropriate injection angle. In many cases, a small injection angle, such as within the range of 2, 5, or 8 to 12 or 15 degrees, is very advantageous. In other cases, a larger injection angle may be better, such as within the range of 25, 30, or 45 to 60 or 90 degrees.

The term "effective amount" refers to the amount of a soft tissue filler composition sufficient to produce a beneficial or desired cosmetic (aesthetic) effect.

As used herein, “subject” can refer to any individual or patient who requires treatment or application for cosmetic (aesthetic) purposes, such as mammals and preferably humans.

The invention described above will now be further explained by the following non-limiting embodiments and examples, wherein further optional features of the invention are disclosed in the accompanying drawings and the description thereof. All features and all combinations of features described above and/or outlined below and/or illustrated only in the drawings can be implemented in embodiments of the invention in the described combinations or individually or in at least one other combination not expressly described herein (since such a combination is technically reasonable).

Attached Figure Description

The accompanying drawings, which are incorporated herein and constitute a part of the specification, schematically illustrate preferred embodiments of the invention described above, and in particular, preferred embodiments of the invention, and together with the description, serve to explain the principles and at least some features of the invention, wherein the same reference numerals are used for the same parts. In the drawings:

Figure 1 is a perspective view of a first example of an embodiment of a syringe assembly according to the present invention, including a first example of a plunger according to the present invention and an example of a finger gripper according to the present invention.

Figure 2 is a perspective view of a second example embodiment of a syringe assembly according to the present invention, including a second example of a plunger according to the present invention and a finger gripper identical to that in the syringe assembly of Figure 1.

Figure 3 is a side view of the syringe assembly in Figure 1.

Figure 4 is a longitudinal cross-sectional view through the syringe assembly shown in Figures 1 and 3.

Figure 5 is a top view of the proximal surface of the plunger of the syringe assembly in Figure 1.

Figure 6 is a top view of the proximal surface of the plunger of the syringe assembly in Figure 2.

Figure 7 is a first side view of the plunger in Figure 1.

Figure 8 is a first side view of the plunger in Figure 1.

Figure 9 is a longitudinal cross-sectional view through the plunger in Figure 1.

Figure 10 is an enlarged view of the plunger in Figure 10 along the cross-section of A-A'.

Figure 11 is an enlarged view of the distal end of the plunger shown in Figure 9.

Figure 12 is an enlarged view of the proximal end of the plunger shown in Figure 9.

Figure 13 is an enlarged bottom view of the piston of the syringe assembly in Figure 4.

Figure 14 is an enlarged view of the cross-section of the piston of the syringe assembly in Figure 4.

Figure 15 is a first perspective view of the finger gripper of the syringe assembly according to the present invention, as illustrated in the preceding figures.

Figure 16 is a second perspective view of the finger gripper illustrated in Figure 15.

Figure 17 is a top view of the finger gripper illustrated in Figures 15 and 16.

Figure 18 is a side view of the finger gripper illustrated in Figures 15 to 17.

Figure 19 is a perspective view of the syringe barrel of the syringe assembly illustrated in Figure 1.

Figure 20 is a longitudinal cross-sectional view through the syringe barrel of Figure 19, and

Figure 21 is an enlarged view of the tip cap at the distal end of the syringe barrel illustrated in Figure 20.

Detailed Implementation

Figure 1 illustrates a perspective view of a first example of an embodiment of a syringe assembly 100 according to the invention, wherein the syringe assembly 100 includes a first example of a plunger 20 according to the invention and an example of a finger gripper 30 according to the invention, wherein the syringe assembly 100 is assembled from components of an example kit according to the invention, and wherein the plunger 20 and the finger gripper 30 are each manufactured by a method according to the invention.

The syringe assembly 100 also includes a syringe barrel 10 having an inner cavity 13 (see, for example, FIG. 4), which is pre-filled with a liquid composition (not shown), wherein the liquid composition is a hyaluronic acid dermal filler. The proximal end of the syringe barrel 10 is closed and sealed by a tip cap 40.

The plunger 20 can be moved along the longitudinal axis A of the syringe barrel 10 into the syringe barrel 10 for dispensing the composition stored in the inner cavity 13 (see, for example, FIG. 4) of the syringe barrel 10, and in particular for ejecting the composition from the barrel 10 after the tip cap 40 is removed.

The plunger 20 includes a plunger head 22 and a plunger rod 21, each injection-molded from polypropylene (PP), wherein the plunger head 22 and plunger rod 21 are integrally formed. This means that they are integrally molded. The plunger head 22 includes a proximal-facing surface 24, and a gripping pad 23 is also applied to said surface by injection molding to facilitate individual gripping, thereby improving the user's thumb contact. The gripping pad 23 is made of thermoplastic elastomer (TPE), which allows for safe and precise support of the user's thumb during use of the syringe assembly 100, and thus precise application of the composition stored in the syringe barrel 10.

In this example of the plunger 20 according to the invention, the gripping pad 23 attached to the plunger head 22 is integrally formed through only one injection point 26 (see FIG. 5). The gripping pad 23 extends almost over the entire proximal-facing surface 24 of the plunger head 22, except for some areas not filled or covered by the gripping pad material 23. In this example of the plunger 20 according to the invention, the areas not filled or covered by the gripping pad material are completely surrounded by the gripping pad material 23.

Because the hyaluronic acid dermal filler composition stored in the syringe barrel 10 of the syringe assembly 100 requires high extrusion and ejection forces due to its high viscosity, the plunger rod 21 must be able to resist kinking. To avoid mechanical failure during use, the plunger rod 21 has a double mushroom-shaped profile almost along its entire length, as also shown in Figures 4 and 7 to 10. Therefore, very good mechanical strength can be achieved, particularly for the plunger 20 configured for use with the syringe barrel 10 of the syringe assemblies 100 and 200 shown in Figures 1 and 2, which is configured to receive and store 1 ml of the composition to be administered, wherein the inner cavity 13 of the syringe barrel 10 has a relatively small inner diameter, particularly compared to the inner cavity of a standard syringe barrel according to ISO 11040-6, with a smaller inner diameter and a larger length. By reducing the inner diameter of the inner cavity 13, i.e., through its smaller inner diameter, the extrusion force during use can be reduced, which also helps to reduce the risk of mechanical failure of the plunger 20, and especially the plunger rod 21. In an alternative embodiment, the plunger rod 21 may include a large-area cross-section, particularly an elliptical, circular, or square cross-section, wherein said large-area, particularly elliptical, circular, or square cross-section may extend only over a portion of the length of the plunger rod 21, over several portions in the longitudinal direction of the plunger rod 21, or may extend over the entire length of the plunger rod 21. The dimensions and geometry of the cross-section of the plunger rod 21 may remain constant or vary over the length of the plunger rod 21. In one embodiment, the geometry and/or dimensions of a cross-sectional region of the plunger rod may, for example, remain constant over at least 80% or 90% of the full length of the plunger rod.

The finger gripper 30 includes a finger gripper body, also integrally formed by injection molding of polypropylene (PP), having two flanges or wings 31 and 32 extending radially in opposite directions from a central hole 37 in the finger gripper body. A plunger 20 is inserted through the central hole 37. Wings 31 and 32 extend to the right and left of the central hole 37, respectively. Each wing 31 and 32 acts as a gripping portion and has a finger contact area 35 on which at least one of the user's fingers can be partially placed during application of the composition stored in the syringe barrel 10 to support the finger during application. Each wing 31 and 32 includes a distally facing surface 33 and a proximally facing surface 34.

According to the invention, the finger gripper 30 includes at least one gripping pad 35, in this example two gripping pads 35, wherein each gripping pad is attached to the distally facing surface 33 of one of the wings 31, 32 and extends almost the entire distally facing surface 33. The two gripping pads 35 are manufactured by injection molding, wherein in this example of the finger gripper 30 according to the invention, the gripping pads 35 are directly applied to the distally facing surface 33 during injection molding.

The grip pads 35 attached to flanges 31 and 32 are also made of thermoplastic elastomer (TPE) in a single piece, with each grip pad having only one injection point 26 (see Figures 16 and 17). These grip pads 35 also improve the grip on the syringe assembly 100 and help prevent the user's fingers from slipping during the application of the composition stored in the syringe barrel 10.

The grip pad 35 of the finger gripper 30 also includes areas 36 that are not filled with grip pad injection molding material 35, wherein these areas form parallel and laterally extending stripes 36 that are completely surrounded by grip pad material 35.

The finger gripper 30 is connected to the proximal end of the syringe barrel 10 via a flange 12 (see, for example, FIG. 4) formed at the proximal end of the syringe barrel 10, wherein the flange 12 is inserted into a side groove 38 in the finger gripper 30 (see, for example, FIG. 4). The plunger rod 21 of the plunger 20 is inserted through a central hole 37 such that the distal end of the plunger rod 21 is at least partially disposed in the inner cavity 13 of the syringe barrel 10.

To facilitate differentiation and avoid misuse of the composition stored in the syringe barrel 10 of the syringe assembly 100, the grip pad 23 attached to the plunger head 22 and the grip pad 35 attached to the finger gripper body 30, with its wings 31 and 32 respectively, are made of colored grip pad material, particularly colored TPE, wherein the color is associated with the specific composition of the hyaluronic acid dermal filler stored in the syringe barrel 10. This allows physicians to identify at a glance which composition the corresponding syringe assembly 100 to be used contains.

Figure 2 shows a second example of an alternative embodiment of the syringe assembly 200 according to the invention, in which the gripping pad 23 attached to the plunger head 22, particularly its proximal surface 24, is designed such that it represents a symbol, specifically a "+". In this case, the "+" symbol is associated with a composition containing the active ingredient lidocaine. This design of the gripping pad 23 of the plunger 20 allows a physician to immediately identify a syringe assembly 200 that has been selected and filled with a composition containing lidocaine. Therefore, the risk of misadministration due to confusion between syringe assemblies containing different compositions to be administered can be reduced.

Figure 3 shows a side view of the syringe assembly 100 illustrated in Figure 2, in which the arrangement of the gripping pads 35 on the finger gripper 30, especially its distal surface 33, can be clearly seen.

Figure 4 shows a longitudinal section through the syringe assembly 100 of Figures 1 and 3, in which the connection of the plunger 20, and in particular the plunger rod 21, to the syringe barrel 10 and the finger gripper 30, as well as the connection between the finger gripper 30 and the syringe barrel 10, can be seen.

In particular, it can be seen from the illustration of Figure 4 how the flange 12 at the proximal end of the syringe barrel 10 is inserted into the groove 38 of the finger gripper 30 to connect the syringe barrel 10 to the finger gripper body 30. Further, it can be seen that the distal end of the plunger rod 21 is inserted into the cavity of the syringe barrel 10 through the central hole 37. At the distal end 25 of the plunger, the plunger 20 is connected to the piston 50, specifically by a snap-fit connection, wherein the piston 50 in this example of the syringe assembly 100 is made of the elastomeric material FM257.

In order to achieve good adhesion between the proximal surfaces 24 of the gripping pad 23 and the plunger head 22, and between the distal surfaces 33 of the gripping pad 35 and the finger gripper body 30, the surfaces to which the gripping pads 23 and 35 are respectively applied include a plurality of grooves 27 and 39 (see Figures 4 and 12), which are filled by the gripping pad injection molding material during the injection molding process of the gripping pads 23 and 35.

Figure 4 shows in further detail that the distal end of the syringe barrel 10 is closed and sealed by a tip cap 40. To attach the tip cap 40 to the syringe barrel 10, the syringe barrel 10 includes a Luer lock connector 11 at its distal end. The tip cap 40 includes a rigid outer part 41 and a resilient inner part 42. The rigid outer part 41 engages with the internal threads of the Luer lock connector 11. The resilient inner part 42 of the tip cap 40 is inserted into the rigid outer part 41, partially extending into the outlet channel 15 at the distal end of the syringe barrel 10 as a truncated conical projection, see also Figures 20 and 21.

Figure 5 shows a top view of the plunger 20 of the syringe assembly 100 illustrated in Figure 1, where a single injection point 26 is shown for manufacturing the gripping pad 23, which is made as a single piece. In this example, the injection point 26 is located near the outer edge of the gripping pad 23. To improve the adhesion between the gripping pad injection molding material 23 and the proximal-facing surface 24 of the plunger head 22 of the plunger 20, the plunger 20 is made of an injection molding tool (not shown) with a tool surface responsible for shaping the proximal-facing surface 24. This tool surface has been etched to produce a surface roughness conforming to VDI 3400Ref.27, where Ra = 2.24 μm and Rmax = 9.0 μm.

Figure 6 shows a top view of the plunger 20 of the syringe assembly 200 illustrated in Figure 2, wherein the gripping pad 23 of the proximal surface 24 of the plunger head 22 attached to the plunger 20 is also integrally formed by injection molding using only one injection point 26. The injection point 26 is also located near the outer edge and outer periphery of the gripping pad 23, respectively. Unlike the gripping pad 23 of the plunger 20 illustrated in Figure 5, the gripping pad 23 of the plunger illustrated in Figure 6 is designed such that its representative symbol, in particular "+", as already described in Figure 2, indicates that the composition pre-filled in the syringe barrel 10 of the syringe assembly 200 contains lidocaine.

Figures 7 and 8 show different side views of the plunger 20 of the syringe assembly 100 illustrated in Figure 1, wherein the illustration in Figure 8 shows the plunger 20 rotated about 90° about its longitudinal axis A compared to the illustration in Figure 7.

Figure 9 shows a longitudinal cross-sectional view of the plunger 20 according to Figures 1, 7 and 8, in which the double mushroom-shaped profile of the plunger rod 21 is visible in Figure 9.

Figure 10 shows an enlarged view of the cross section along section A-A' of the plunger of Figure 10, through which the double profile of the plunger rod 21 becomes apparent.

Figure 11 shows an enlarged view of the distal end 25 of the aforementioned plunger 20 illustrated in Figure 9, wherein the distal end 25 of the plunger rod 21 can be connected to the piston (see, for example, Figures 4 and 14 - piston 50) via a snap-fit connection. The distal end 25 of the plunger rod 21 includes a mushroom-shaped tip 25A. In this example, the plunger tip 25 also includes a piston receiving portion 25B arranged proximally adjacent to the mushroom-shaped tip 25A, having a smaller diameter than the mushroom-shaped tip 25A. The piston receiving portion 25B is limited in the proximally by a disc-shaped axial piston stop 25C used for axially fixing the piston (not shown here). Thus, a secure connection between the distal end 25 of the plunger rod 21 and the piston 50 can be achieved.

Figure 12 shows an enlarged view of the proximal end of the plunger 20 shown in Figure 9. The proximal-facing surface 24 of the plunger head 22 includes two circular grooves 27 concentrically arranged around the longitudinal axis A, wherein the grooves are filled with the gripping pad material 23 during the application of the gripping pad material 23 to the proximal-facing surface 24 of the plunger head 22. These grooves 27 increase the contact area between the proximal-facing surface 24 and the gripping pad material 23, thereby improving adhesion between the gripping pad material 23 and the plunger head 22.

Figure 13 shows an enlarged bottom view of the piston 50 of the syringe assembly 100 illustrated in Figure 4, and Figure 14 is an enlarged cross-sectional view of the piston 50, wherein the piston 50 is configured to snap into contact with the mushroom-shaped tip 25 of the plunger rod 21. To ensure a tight fit with the wall of the inner cavity 13 of the syringe barrel 10, the piston 50 includes a wavy external geometry. On its bottom side 51, the piston 50 includes several unlabeled protrusions configured to contact the axial piston stop 25C of the plunger rod 21.

Figures 15 to 18 show different views of an example of a finger gripper 30 of the syringe assemblies 100 and 200 shown in Figures 1 and 2 according to the invention, wherein from Figures 15 to 18, in particular the curved shape of the wings 31 and 32, the design and arrangement of the gripping pads 35 on the distal surface 33, the central hole 37, and the side grooves 38 for connecting the finger gripper 30 to the proximal end of the syringe barrel 10 become apparent.

Similar to the plunger head gripping pad 23 of the plunger 20 of the syringe assemblies 100 and 200 illustrated in Figures 1 and 2, the gripping pad 35 of the finger gripper 30 is also manufactured by injection molding. The gripping pad 35 is also integrally formed from colored TPE using only one injection point 26, wherein the gripping pad material 35 has been directly applied to the distally facing surfaces 33 of the wings 31, 32. The injection point 26 is also located at the outer edge of the gripping pad 35, extending almost entirely onto the corresponding surface 33. As described above, some areas 36 forming the parallel and laterally extending stripes 36 are not filled or covered by the gripping pad material 35, but are completely surrounded by it to achieve a good economical tactile feel and good finger contact, reducing the risk of any user's fingers slipping.

Figure 19 shows a perspective single view of the syringe barrel 10 of the syringe assembly 100 shown in Figure 1, wherein the inner cavity 13 of the barrel 10 is pre-filled with hyaluronic acid dermal filler. The distal end of the barrel 10 is closed and sealed by a tip cap 40. The proximal end of the syringe barrel 10 includes a flange 12 that can be laterally inserted into a groove 38 of a finger gripper 30 for attaching the syringe barrel 10 to the finger gripper 30 and vice versa.

Figure 20 shows a longitudinal section passing through the cylinder 10 in Figure 19.

Figure 21 shows an enlarged view of the tip cap 40 of Figure 20. It can be seen that the syringe barrel 10 includes a Luer lock connector 11 at its distal end, wherein the Luer connector includes internal threads and a Luer cone 14 surrounding an outlet channel 15, which is in fluid communication with the inner cavity 13 of the syringe barrel 10.

The distal end of the syringe barrel 10 is closed and sealed by a tip cap 40, which includes an external rigid member 41 that engages with the internal thread of a Luer lock connector 11, and an internal elastic member 42 that is inserted into the external rigid member 41 to close and seal the outlet channel 15 of the syringe barrel 10.

In this example, the maximum outer diameter Dmax of the rigid member 41 is less than or equal to the outer diameter of the Luer connector 11 of the syringe barrel 11. Therefore, the risk of accidental jamming or damage to the tip cap 40 can be reduced, thereby reducing the risk of closure and sealing of the pre-filled syringe barrel 10. In particular, the outer wall of the rigid member is at least partially flush with the outer wall of the Luer lock connector.

All features described herein with respect to one aspect of the invention may also be implemented individually or in combination in any other subject according to any other aspect of the invention, provided that this is technically possible.

List of reference numerals

100 A first example of an embodiment of the syringe assembly according to the present invention

200 A second example of an embodiment of the syringe assembly according to the present invention

10. Syringe barrel

11. Luer lock connector

12. The proximal end flange of the syringe barrel.

13. Luer cone of Luer lock connector

15. Export Channel

20. Examples of embodiments of the plunger according to the invention

21. Piston Rod

22. Piston head

23. Plunger head gripping pad

24. The proximal surface of the plunger head.

25. The plunger tip at the distal end of the plunger rod.

25A Mushroom-shaped tip of the plunger rod

25B Piston Receiving Section

25C Axial piston stop

26 Injection sites

27. Grooves in the proximal surface of the plunger head.

30. Examples of embodiments of the finger gripper according to the present invention

31. Right flange or wing of the main body of the finger gripper

32. Left flange or wing of the main body of the finger gripper

33. The distal surface of the main body of the finger gripper.

34. The proximal surface of the main body of the finger gripper.

35. Grip pads for finger grippers

36. Areas of the grip pad not filled or covered by injection-molded material that are designed as stripes and are not gripped by fingers.

37. Center hole in the main body of the finger gripper

38 A groove for final insertion into the proximal flange of the syringe barrel.

39. Grooves in the distal-facing surface of the finger gripper body.

40 Tip Cap

41. Rigid components (external components) of the tip cap

42. The elastic component (internal component) of the tip cap.

50 Piston

51 Piston bottom side

A. The longitudinal axis of the syringe barrel

Dmax is the maximum outer diameter of the rigid component of the tip cap.

Claims (15)

1. A plunger (20) for a syringe assembly (100, 200) for administering a liquid composition, The plunger (20) includes a plunger rod (21) and a plunger head (22). The plunger rod (21) includes a proximal end and a distal end (25), and The plunger head (22) is attached to the proximal end of the plunger rod (21) and includes a proximal-facing surface (24) configured to act as a thumb plate during application. The plunger (20) is characterized in that it includes a gripping pad (23) attached to the proximal surface (24) of the plunger head (22) and extending at least partially over the proximal surface (24), wherein the gripping pad (23) is formed by injection molding. 2. The plunger (20) according to claim 1, characterized in that the gripping pad (23) on the plunger head (22) is made of thermoplastic elastomer (TPE), particularly of colored thermoplastic elastomer (cTPE). 3. The plunger (20) according to claim 1 or 2, characterized in that the proximal surface (24) of the plunger head (22) includes at least one deepened portion (27), in particular at least one groove (27) filled with a gripping pad injection-molded material (23). 4. The plunger (20) according to any one of the preceding claims, characterized in that the gripping pad (23) on the plunger head (22) is designed such that it represents a symbol ("+"), in particular a letter or another character selected from ASCII code. 5. The plunger (20) according to any one of the preceding claims, characterized in that the gripping pad (23) on the plunger head (22) is made as a single piece and includes only one injection point (26). 6. The plunger (20) according to any one of the preceding claims, characterized in that the plunger rod (21) includes at least one portion in its longitudinal direction, said portion being at least substantially a double-T profile shape, a similar double-T profile shape, an I profile shape, or a similar I profile shape. 7. A method for manufacturing a plunger (20) according to any one of claims 1 to 6, comprising at least the following steps: - Manufacture the plunger head (22), - The gripping pad (23) is formed by injection molding. 8. A finger gripper (30) for an injector assembly for administering a liquid composition, comprising a finger gripper body (30) having two flanges (31, 32) extending radially in opposite directions from a central hole (37) in the finger gripper body, through which a plunger (20) of the injector assembly can be inserted, each flange (31, 32) acting as a gripping portion and having a finger contact area, wherein at least one of a user's fingers can be partially placed on the finger contact area during administration to support the finger during administration, wherein each flange (31, 32) includes a distally facing surface (33) and a proximally facing surface (34). The finger gripper (30) is characterized in that it includes a gripping pad (35) attached to the distal surface (33) of at least one of the flanges (31, 32), the gripping pad extending at least partially onto the distal surface (33), wherein the gripping pad (35) is formed by injection molding. 9. The finger gripper (30) according to claim 8, characterized in that at least one gripping pad (35) on the finger gripper (30) is made of thermoplastic elastomer (TPE), particularly of colored thermoplastic elastomer (cTPE). 10. The finger gripper (30) according to claim 8 or 9, characterized in that at least one gripping pad (35) on one of the flanges (31, 32) of the finger gripper is made as a single piece and includes only one injection point (26). 11. A method for manufacturing a finger gripper (30) according to any one of claims 8 to 10, comprising at least the following steps: - Manufacture a finger gripper body (30) comprising two flanges (31, 32) extending radially in opposite directions from a central hole (37) in the finger gripper body (30), through which a plunger (20) of a syringe assembly (100, 200) can be inserted, each flange (31, 32) acting as a gripping portion and having a finger contact area, on which at least one of the user's fingers can be partially placed during application to support the finger during application, wherein each flange (31, 32) includes a distally facing surface (33) and a proximally facing surface (34), and - The gripping pad (35) is formed by injection molding. 12. A syringe assembly (100, 200) for administering a liquid composition to a human or animal body, comprising at least: A longitudinal syringe barrel (10) having an inner cavity (13) for receiving and storing the liquid composition to be administered. The finger gripper (30) is attached to the proximal end of the cylinder (10), and A plunger (20) having a plunger rod (21) and a plunger head (22), wherein the distal end (25) of the plunger rod (21) is at least partially disposed within the inner cavity (13) of the cylinder (10). The plunger (20) is characterized in that it is a plunger (20) manufactured according to any one of claims 1 to 6 or according to the method of claim 7, and/or the finger gripper (30) is a finger gripper (30) manufactured according to any one of claims 8 to 10 or according to the method of claim 11. 13. The syringe assembly (100, 200) according to claim 12, characterized in that the syringe barrel (10) includes a Luer lock connector (11) integrally formed with the syringe barrel (10) at its distal end, wherein the syringe assembly (100, 200) further includes a tip cap (40) covering and sealing the distal end of the syringe barrel (10), wherein the tip cap (40) is a two-part tip cap (40) including a rigid member (41) and an elastic member (42), wherein the maximum outer diameter (Dmax) of the rigid member (41) is less than or equal to the outer diameter of the Luer lock connector (11) of the syringe barrel. 14. A kit comprising components of a syringe assembly (100, 200) according to claim 12 or 13, said components being configured to assemble into a syringe assembly (100, 200) according to claim 12 or 13, wherein said kit comprises at least: A longitudinal syringe barrel (10) having an inner cavity (13) for receiving and storing the liquid composition to be administered. A finger gripper (30) configured to attach to the proximal end of the cylinder (10), and A plunger (20) having a plunger rod (21) and a plunger head (22), wherein the distal end of the plunger rod (21) is configured to be at least partially disposed within the cavity (13) of the cylinder (10). The plunger (20) is characterized in that it is a plunger (20) manufactured according to any one of claims 1 to 6 or according to the method of claim 7, and/or the finger gripper (30) is a finger gripper (30) manufactured according to any one of claims 8 to 10 or according to the method of claim 11. 15. Use of a syringe assembly (100, 200) according to claim 12 or 13 or a kit according to claim 14, the syringe assembly or the kit being used for cosmetic or therapeutic applications, particularly for replacing or filling biological tissue or increasing the volume of biological tissue, wherein an effective amount of the liquid composition, particularly an effective amount of the dermal filler composition, is applied to a subject.