HK1089397B - Needleless syringe comprising an optimized injector-receptacle - Google Patents

Description

Needleless injector with optimized injector-reservoir

Technical Field

[01] The present invention relates to the field of disposable needleless injectors; such syringes are used for intradermal, subcutaneous and intramuscular injection of liquid active principles for human or veterinary medical treatment.

Background

[02] The primary pressing need for needleless injectors is the long-term compatibility between the active liquid ingredient and its container. Another urgent need is to have a transparent container to control the correct injection of the liquid medicine into the container before the syringe is used. These desiderata result in the manufacture of containers which are substantially transparent, using materials which are compatible in the desired period with the active principle, generally pharmaceutical borosilicate glasses: type I glass or type II glass.

[03] The initial stage of injection is critical for penetration of the liquid jet into the skin, the liquid jet depending on how many syringes have one or more syringes. The latter configuration is beneficial for pain relief. The final bio-usability (biodissonilitite) depends on a good implementation of this initial phase, provided that the liquid is injected rapidly in the syringe, without multiple jumps of the beam, even if the liquid impact (coup de bilier) is too large to inject rapidly.

[04] WO01/58512 proposes a needleless injector comprising a container closed by an upstream and a downstream stopper confining the active liquid component, said container being initially isolated from an injector or reservoir (septum) having at least two syringes on its outer lateral surface and a central blind hole in which the downstream stopper is mounted so as to release the syringe inlet when the downstream stopper-active component-upstream stopper assembly is moved by the motive means for carrying out the injection.

[05] A fundamental difficulty with such injectors is the non-optimization of the syringe inlet. Non-optimization results in loss of pressure on the one hand and loss of residual liquid in the dead volume on the other hand. In this document, the inlet is a radial groove located over the entire upstream surface of the reservoir. Finally, the shape of the upstream opening of the central bore is not optimal and can scratch the blockage when engaged.

[06] In this invention, a big problem is not solved well, namely that during the injection phase the pressure to the reservoir is reduced, i.e. the pressure is adjusted to the reservoir size. In view of the installation performed, the entire reservoir surface supported on the container is subjected to pressure, since the packing material is sealed off outside the container, since the use of an annular sealing ring here makes it particularly impossible to create an inlet radial groove in the injection tube.

Disclosure of Invention

[07] The present invention aims to solve the problem of optimizing the syringe inlet and reducing the pressure to the reservoir during injection.

[08] The invention relates to a needleless injector comprising a body housing a cylindrical container closed by a movable upstream and downstream obturating member which confine the active principle, and comprising downstream an injector-reservoir, referred to as reservoir, having at least two peripheral syringes, said reservoir being supported on the container and comprising a blind hole whose free height releases the inlets of the peripheral syringes when the downstream obturating member comes into contact with the bottom of the reservoir hole due to the action of power means which move the upstream obturating member-liquid-downstream obturating member assembly, said injector being characterized in that each inlet comprises a dimple (lamage) positioned on the syringe and connected to a radial recess leading to the central hole. The countersink is preferably centered on the syringe.

[09] In this document, the adjective downstream means any component close to the injection site, or any component part directed towards the injection site, said site being the skin of the patient. Conversely, the adjective upstream denotes any component that is remote from the injection site, or any component part that faces away from the site. Thus, the reservoir has a downstream surface facing the skin of the patient and an upstream surface opposite thereto, and is supported on the container; the downstream surface and the upstream surface are connected by a side surface.

[10] In the present invention, the active liquid component or the drug means a substantially viscous liquid, a liquid mixture, or a gel. The active ingredient may be a solid, in solution in a suitable solvent, for injection. The active ingredient may be a powdered solid suspended in a suitable liquid at approximately a certain concentration. The particle size of the active solid ingredient (granulomtie) must be appropriate, as must the shape of the syringe to prevent clogging.

[11] The container is substantially cylindrical and is made of type I glass or type II glass, but can be made of any other transparent material compatible with the active principle. The upstream and downstream surfaces of the vessel are substantially planar, the plane containing them being perpendicular to the axis of symmetry of the vessel. The upstream and downstream surfaces support the syringe body and the reservoir, respectively. The bearing surfaces of the two parts have gaskets, the properties of which will be specified hereinafter.

[12] The syringe passes through the entire height of the reservoir from the upstream surface to the downstream surface. The syringes have at least two, called perimeter syringes, as arranged in the reservoir around the central blind hole. The injection tube communicates with the central bore only through the inlet as described hereinafter. The syringe has a different cross-section from upstream to downstream, depending on its implementation on the one hand, and on the other hand in order to obtain a sufficiently fine and rapid jet to enter the skin of the patient at the desired depth. Typically, the syringes are identical, arranged equidistantly around a central blind hole, with their axis parallel to the axis of the reservoir, but the syringes may also be different.

[13] The power means acting on the upstream obstruction may be a mechanical transmission mechanism: the compression spring or the pneumatic spring is relaxed, the compressed gas or the firework type expands, and the fuel gas expands.

[14] The operation of the injector is as follows: the motive means acts on the upstream obstruction to displace the upstream obstruction-liquid-downstream obstruction assembly as the liquid is incompressible. The downstream obturating member moves into the blind hole of the reservoir until it comes into contact with the bottom of said hole. The height of the hole is such that: when the downstream obturating member is in contact with the bottom of said orifice, the inlet of the syringe is free on the periphery of the orifice of the reservoir, and, as the upstream obturating member moves, the liquid is forced and ejected until the container is empty, the upstream obturating member thus being in contact with the downstream obturating member.

[15] The inlet of a syringe on the upstream surface of the reservoir comprises a countersink positioned and preferably centred on the syringe and a radial groove connecting said countersink to the central blind hole of said reservoir.

[16] The diameter of the dimple forming the syringe inlet is about 1.1 to 1.5 times, preferably about 1.2 times the diameter of the syringe. The depth of the countersink is about 0.5 to 0.7 times the diameter of the syringe, preferably about 0.6 times the diameter of the syringe.

[17] A radial groove associated with the dimple connects the hole to the syringe. The depth of the radial groove is equal to the depth of the dimple. The width of this radial groove is either constant and equal to the diameter of the dimple, or it increases from its width at the junction with the dimple to its high value at the exit of the central hole, but this high value remains less than about 1.4 times the diameter of the syringe.

[18] The dimple can be processed by the common technology: i.e. machined around a hole in the shape of a straightened circular counterbore, in which case the side surface of the dimple is perpendicular to the upstream flat surface of the reservoir and the bottom of the dimple.

[19] However, the countersink may also be broadly understood, wherein the side surface of the countersink is no longer perpendicular to but inclined to the upstream surface, again connected to the bottom of the countersink by a fillet (arrondi). In this case, the dimensions of the countersink and the radial recess are taken from the upstream portion thereof.

[20] The upstream surface of the reservoir has a central bore consisting of a central blind bore, and inlets connecting the bore to the respective syringes. The edge of the orifice is the upstream flat surface and the intersection of the orifice with the side surface of the inlet. In theory, the edge is a generally sharp edge, but the edge is blunt, often having an appropriate radius of curvature at the portion where the central bore edge portion and the radial groove intersect, so as to not damage or score the downstream obstruction as it enters and passes through the central bore at start-up.

[21] The upstream surface has a parallel multilobal (multilobal) gasket at most near the edge of the central aperture. The gasket is referred to as being parallel to the rim because its distance to the rim in a direction perpendicular to the rim is constant, and the gasket is referred to as being as close to the rim as possible because the distance is as small as possible according to the embodiment of the reservoir. The gasket is multilobal in that it surrounds the inlet of the syringe tube from the outside, parallel and as close to the edge as possible; here, the outer concept is away from the axis.

[22] For example, the described multileaf seal reduces the surface of the reservoir exposed to liquid pressure during injection relative to a circular seal surrounding the orifice and the inlet of the syringe because the multileaf seal is closer to the edge of the orifice than the circular seal for the section between the syringes.

[23] According to a first embodiment, the multilobal gasket is a fitted gasket, which is fitted in an engagement-type groove on the upstream surface of the reservoir. This embodiment involves the precise installation of the gasket in the groove, followed by careful handling, the bearing being installed on the container and then in the syringe body.

[24] According to a second preferred embodiment, when the reservoir is made by injection, for example, the multileaf gasket is made by double injection (biinjection). The double shot multi-lobed gasket has a central thickness margin on its outer surface, the compression and deformation of which ensures sealing when the reservoir and container are supported.

[25] Furthermore, it is known to use the double injection technique in which the material for producing the multilobal gasket is injected into a cavity provided for this purpose in a reservoir by means of a suitable mold, when the main component, here the reservoir, has been injected and has not yet hardened. Obviously, the cavity must be parallel to the edge of the hole and at most close to the edge. The technique of molding the multilobal gasket with the replica mold is similar to this technique.

[26] The advantage of a multilobal double injection gasket is that a single reservoir-gasket unit is almost immediately available after this second injection to continue with the syringe installation.

[27] The central hole of the reservoir is preferably substantially frustoconical, the inlet diameter of said hole being equal to the internal diameter of the container, the smallest diameter of the hole being towards the bottom of said hole, the normal generatrix of the lateral portions making an angle of about 2 ° to 9 °, preferably about 7 °, with the axis of symmetry of the hole. The bottom of the hole is connected to the side portion by a suitable fillet.

[28] The depth of the holes is such that: when the downstream obturating member bears on the bottom of the bore, the inlet of the syringe is unblocked, allowing the reservoir to communicate with the syringe. The relatively open shape of the orifice allows the downstream obturating member to enter the chamber, to be deformed regularly during this phase and to be cushioned during this working phase, limiting the force applied to the reservoir.

[29] The present invention is applied to a disposable pre-filled syringe, which has the advantage that the device can be divided into two parts. One part, referred to as the medicament-related part, comprises a body and a container with a movable upstream and downstream stopper and an injector-reservoir, which can be handled under pharmaceutical conditions, in particular sterilized and disinfected. The assembly of the component to the syringe with its components already assembled is carried out under less stringent conditions than those of the pharmaceutical industry.

[30] When the downstream stopper is received in the bore of the reservoir, the syringe is difficult to reuse. Thus, an advantage of this arrangement is that it prevents the syringe from being reused for a different purpose of treatment.

[31] Finally, this configuration is advantageous in that leakage of liquid through the syringe prior to injection is avoided. In practice, the device is often shaken, or even advocated to check the turbidity of the liquid, or to homogenize the mixture when the liquid has suspended particles. Before injection, the effective components are isolated from the injection tube, and are protected to the maximum extent to prevent loss.

Drawings

[32] The invention will now be further described with reference to the accompanying drawings and non-limiting examples.

The attached drawings are as follows:

[33] FIG. 1 is a longitudinal cross-sectional view of a syringe according to a first embodiment of the present invention;

[34] FIG. 2 is an enlarged view of a downstream portion of the injector;

[35] FIG. 3 is a perspective view of another embodiment of the reservoir of the present invention;

[36] FIG. 4 is a cross-sectional view of the reservoir, the cross-section passing through the central axis of the reservoir and the axis containing the syringe;

[37] figures 5, 6 and 7 are schematic perspective views of different embodiments of inlets in injection tubes.

Detailed Description

[38] Fig. 1 is a vertical partial longitudinal cross-sectional view of the injector of the present invention with the injection system oriented downstream in the lower portion.

[39] The syringe 1 has a body 2 in which is received a container 3 containing an active liquid ingredient 6. At the downstream end of the body 2 a reservoir 7 is arranged, which for example comprises three injection tubes, such as tubes 8. The injection system is covered with an external protection device to ensure sterility of the syringe: the protector comprises an elastomeric membrane, a thin metal cap fitted around the end of the syringe so that it abuts against the outer surface of the injector. The protector is removed prior to injection. At its opposite end, the injector body 2 is connected to a power unit 70, which in this embodiment is a fireworks-producing gas generator, as will be described hereinafter. The container 3 is supported on the body 71 of the power unit 70, and a ring seal ensures sealing.

[40] The syringe body 2 has two diametrically opposed windows for the visual access to the active principle contained in the container 3: the window is simply two rectangular openings in the body. Downstream of the syringe body 2, in a suitably shaped bore, a conical cylindrical reservoir 7 is fitted, as will be described hereinafter. A glass container 3, which is a tube, is supported on the reservoir 7 and centered downstream of the body 2. Upstream of the injector body 2 is received a power unit body 71 which is centred around the other end of the container. The container 3 is substantially a tube closed at both ends by a movable upstream and downstream stopper 4, 5, preferably plungers of the type commonly used in syringes, these elements being moulded from an elastomeric material which is long-term compatible with the active principle, each element acting as a piston and as a seal by means of a flange or lip (not shown in detail). The elastic material usually used for manufacturing these members is, for example, chlorobutyl rubber (chlorobutyl) or bromobutyl rubber (bromobutyl), the shore hardness of which is about 45 to 70. These members may be surface treated, in particular to facilitate their movement along the tubular container. The piston plug has a diameter, when in a free state, greater than about 10% of the inner diameter of the receiving tube, and a height of about 0.5 to 0.8 times the diameter. When inserted into the tube, the plunger has a height, due to deformation, equal to about 0.6 to 1.0 times the inside diameter of the container.

[41] In this embodiment, the reservoir 7 is a member of conical cylindrical shape having a central bore 10 in which the downstream obturating member 5 is mounted. The reservoir has three syringes, only one of which is shown in the figures, numbered 8, on its periphery. The diameter of the hole is equal to the diameter of the container. The free height of the blind hole 10 of the reservoir 7 is equal to the free height of the downstream obturating member 5 mounted in the container 3. When the downstream stopper 5 reaches the bottom 7a of the reservoir, the inlet 9 of the injection tube 8 (on the side of the container 3) communicates with the liquid 6; the rate of liquid outflow corresponds to the pressure transmitted by the upstream obturating member 4.

[42] In this embodiment, the power means acts on the upstream obstruction by means of a piston 11, the effective section of the piston 11 being equal to that of the upstream obstruction 4. The piston 11 comes into contact with the upstream obturating member 4 and therefore starts to operate without impact or bumping action. The sealing system of piston 11 prevents the gases generated by the combustion of charge 72 from coming into contact with the upstream obturating member, thus preventing possible damage thereto and preventing the gases from leaking towards the active ingredient contained in the container. The plunger 11 is suitably coloured to indicate its operation in the viewing window of the syringe body 2.

[43] The main components of the firework generator 70 will now be described. It contains a charge 72 of fireworks manufacture in a body 71 above the piston, which burns an explosive agent 73 struck by a firing pin 74. The explosive agent 73 is contained in a fuse sleeve. In the initial position, the striker 74 is retained in the striker guide 75, which is screwed to the body 71, by at least one ball, such as ball 77, which is partially engaged in a neck of the striker. The firing device includes a button 78 having a neck 79 and an internal spring 76.

[44] The push button 78 slides outside the striker guide 75 and is held by a projecting pin 80 that moves in a side slot 81. The button 78 is here a trigger mechanism.

[45] It will be apparent that initiation means other than the striker means described herein may be used for initiating combustion of the fireworks producing charge 72 without departing from the scope of the present invention. It need not be exhaustive, and a battery-powered triggering device, or a piezoelectric triggering device, is cited as an example.

[46] The gas generator is made by fireworks and can be replaced by a gas generator consisting of a compressed gas container closed by a quick-opening plug. The trigger mechanism opens the stopper and the compressed gas in the container expands to act on the propulsion means.

[47] In use, after removing the sterile cover and placing the downstream surface of the injector on the skin of the subject to be treated, the operator presses the button 78 with his thumb, compressing the spring 76. The button is moved until the neck 79 reaches the level of the neck of the striker 74 and a small ball, such as ball 77, holding the striker 74 disengages the neck 79, releasing the striker which violently impacts the explosive agent 73, which ignites the fireworks-making charge 72. The striker 74 is supported on the fuze sleeve 30 to ensure that the explosive agent remains in place and sealed and that the gas does not rise toward the button.

[48] The combustion of the fireworks-manufacturing charge generates gas, which acts on the piston 11.

[49] Figure 1 shows the injector of the invention in the form of a pen: all the members have the same central axis but are stacked. Other configurations are contemplated without departing from the scope of the invention, for example, the power plant section may be angled with respect to the container-reservoir section to make the configuration more compact, as described in FR 2815544.

[50] Fig. 2 is an enlarged view of a downstream portion of the injector.

[51] The reservoir 7 is a member of conical cylindrical shape which fits tightly within the syringe body 2.

[52] The central blind hole 10 is substantially cylindrical. The upstream edge connecting the upstream surface of the reservoir and the orifice preferably has a radius of curvature sufficient not to break the obstruction when it enters the orifice at the beginning of operation.

[53] The reservoir has a plurality of syringes, only one of which is shown in the drawings and is designated by the reference numeral 8. An inlet 9 connects the bore to the injection tube, or rather the upstream portion of the bore. When the downstream obstruction is fully received in the bore, liquid occupying the upstream portion can flow out to the syringe.

[54] As can be seen in the cross-sectional view, a multi-lobed insert 12 is arranged in an engagement neck, at most near the edge of the hole and surrounding the countersink. This point will be described in detail later.

[55] Figures 3 and 4 show another embodiment of the reservoir of the syringe of the present invention. In this embodiment, the reservoir is made by injection of polycarbonate compatible with the actual application.

[56] The reservoir 37 has lateral threads on its lateral surface for mounting with screws on a body of suitable shape. The reservoir has a three-perimeter injection tube, only one of which is shown in cross-section at 38. In this embodiment, the three syringes are identical, arranged equidistantly around the central bore 31 of the reservoir, said bores being connected by an inlet 39. Considering the injection manufacturing mode of the reservoir, the upstream part of the injection tube is rather large, with a diameter of about 0.8 mm and a height of about 4 mm to 5 mm, and this part is cylindrical or conical and extends downstream from a narrower part with a diameter of about 0.1 mm and a height of about 2 mm to 3 mm, so that the beam enters substantially deeply into the skin of the patient.

[57] In this embodiment, the upstream surface of the reservoir has a resilient clip means 40 which receives and retains a container having a flange at its end; the container may be pre-filled with a medical fluid prior to installation on the reservoir; in this embodiment, the separate component constitutes a medicament-related part of the injector, which is operable as a whole. The apparatus will be described in additional detail.

[58] The upstream surface of the reservoir has a tri-lobe seal 34 because in this embodiment there are three injection tubes. The gasket is made by double injection. The tri-lobe seal is parallel, at most near the edge of the aperture and the edge of the inlet, as previously described.

[59] The cavity receiving the three-leaf gasket is rectangular in cross-section as shown in the cross-sectional view. The three-lobed seal occupies the entire cavity, with a thickness allowance 35 on the central portion of its free upstream surface, since the container has not been mounted on the reservoir.

[60] To secure the tri-lobe seal in the cavity of the reservoir, the downstream surface of the seal has equidistantly disposed retaining wedges (picots) that are received in holes in the cavity when the reservoir is injected. Such a wedge 36 is opposite the syringe.

[61]The elastomeric material selected for the bi-injection gasket is suitably attached to its support, which is one of the advantages of the bi-injection technique; it is also suitable for long-lasting ageing, the hardness of which is sufficient to ensure the sealing action. The shore hardness is about 75, which is convenient to implement. If the reservoir is made of polycarbonate, the elastic material of the seal may beThe cards are made.

[62] In this embodiment, the central blind hole is frustoconical with an angle of about 7 °.

[63] The diameter of the inlet, i.e. the diameter of the reservoir upstream of the orifice, is equal to the diameter of the container.

[64] Edge of the hole: the intersection of the upstream surface of the reservoir and the frusto-conical portion of the bore is not cut to sharp edges, but these surfaces are joined with a suitable curvature, as shown in figure 4.

[65] Likewise, the edge of the radial groove: the intersection of the radial groove and the hole is circular, and the curvature radius of the intersection is smaller than that of the hole.

[66] Figures 5, 6 and 7 are partial perspective views showing different embodiments of the structure of the syringe inlet of the reservoir of the invention. Similar parts in these figures are denoted by the same reference numerals as in figures 3 and 4.

[67] FIG. 5 shows a first embodiment of the inlet 39 with a dimple 59 centered on the syringe 38 and a constant width radial groove connecting the dimple with the central bore. In this embodiment, the sides of the dimple and groove are perpendicular to the upstream surface of the reservoir and the bottom 19 of the inlet 39.

[68] Fig. 6 shows another embodiment which differs from the previous one in that the groove is large, at right angles to the hole, and converges in some way to connect to a countersink 59 centred on the syringe 38.

[69] Fig. 7 shows an embodiment in which the width of the groove is constant and the sides of the groove and the countersink 59 are not perpendicular but rounded to join the bottom region 19 of the groove and the countersink with a large radius of curvature, which is an inlet device with a profiled cross-section.

[70] For simplicity, in the three figures, the intersection between the orifice and the upstream surface of the reservoir, and the intersection between the orifice and the radial groove, shown as arcs, can be thought of as sharp edges, which in fact are blunt, with a curvature sufficient to make the connection.

Claims (9)

1. Needleless injector comprising a body (2) housing a cylindrical container (3) closed by a movable upstream obturator (4) and a movable downstream obturator (5) which confine an active principle (6), and comprising downstream a reservoir (7, 37) having at least two peripheral injection tubes (8, 38) supported on the container by its upstream surface and comprising a blind hole (10, 31), the free height of said blind hole (10, 31) allowing the inlet (9) of said peripheral injection tube (8, 38) when said downstream obturator (5) is brought into contact with the bottom (7a) of the hole of said reservoir by the action of a power device (70) which moves said upstream obturator-liquid-downstream obturator assembly, 39) the light-emitting diode is exposed out of the light-emitting diode,

the injector being characterized in that, on the upstream surface of the reservoir, each inlet (9, 39) comprises a countersink positioned on the syringe and associated with a radial recess leading to a central hole (10, 31); and the surface of the reservoir has a multi-lobed gasket (12, 34) which surrounds as close to and parallel to the edge of the bore (10, 31) as possible and as close to the inlet (9, 39) of the syringe as possible.

2. A needleless injector according to claim 1, wherein the multilobal gasket (12) is received in a conjugate groove.

3. The needle free injector of claim 1, wherein the upstream surface of the reservoir has a double injection molded multi-lobed gasket (34) that surrounds as close to and parallel to the edge of the central bore as possible and as close to the inlet of the syringe as possible.

4. A needleless injector as claimed in any preceding claim, in which the dimple centred on the syringe has a diameter in the range 1.1 to 1.5 times the diameter of the syringe and a depth in the range 0.5 to 0.6 times the diameter of the syringe.

5. The needle free injector of claim 4, wherein the radial groove is of constant width and equal to the diameter of the dimple.

6. A needleless injector as claimed in claim 4, wherein the radial recess is of increasing width from its junction with the counterbore to its exit at the central blind hole where its width is at most equal to 1.4 times the diameter of the counterbore.

7. The needle free injector of claim 4, wherein the dimple and the radial groove have a profiled cross section.

8. A needleless injector according to any one of claims 1 to 3, characterized in that the central blind hole (31) is substantially frustoconical, the inlet diameter of the hole being equal to the internal diameter of the container, the smallest diameter being towards the bottom of the hole, and the standard generatrix of the frustoconical lateral portion being at an angle of 2 ° to 9 ° with respect to the axis of the hole.

9. The needle free injector according to claim 8, characterized in that the inlet and the upstream edge of the central bore (31) have a curvature so as not to break the downstream occlusion.