FR2728172A1 - Injection cartridge for auto-injection syringe - Google Patents

Abstract

Injection cartridge comprises a barrel (12) contg. the substances to be injected, situated between a forward wall equipped with a needle, and a rear wall which acts as the piston. The forward wall forms part of a mobile assembly which moves inside the barrel by means of an actuator (88,126) between a retracted position inside the barrel and an active position in which the needle projects beyond the barrel. Also claimed is an auto-injection syringe comprising a box (50, 62, 72, 98) to receive the cartridge with a spring-operated actuator for the rear wall which is under tension and may be released.

Description

 The present invention relates to an injection cartridge, of the type comprising an elongated body in which is contained a substance to be injected disposed between a front wall provided with an injection needle and a rear wall forming a piston, movable in the body and adapted to be associated with actuation means.

It applies in particular to injection cartridges for two-component medical products with extemporaneous mixing.

 The invention also relates to a self-injection syringe comprising an injection cartridge of this type.

 Self-injection syringes are intended for people who require the administration of an active substance for medical reasons, in circumstances where no specialized medical personnel are available, for example in the event of war or during expeditions. distant. Such a syringe allows a non-specialist to inject himself with a substance.

 Self-injection syringes are known comprising an injection cartridge formed from a hollow elongate body containing a substance to be injected and provided at one of its ends with a fixed front wall integral with the body and carrying an injection needle. A piston forming a movable rear wall of the cartridge is mounted movable in translation inside the body. This cartridge is slidably mounted in a tube forming an envelope, and the free end of the piston is associated with spring actuation means.

 Initially, the cartridge and the needle are entirely housed inside the envelope tube, and the spring actuation means are adapted so that, when the syringe is triggered, allow the entire cartridge to be moved. in the tube so that the end needle enters the tissues of the user and then allows the piston to move in the cartridge in order to cause the injection of the substance contained therein.

 These self-injection syringes have the drawback of requiring a large number of parts and are of a complex kinematic arrangement. Indeed, two consecutive displacements are necessary, namely firstly that of the cartridge, then, secondly, that of the piston. The entire cartridge containing the substance to be injected being moved, in order to make the needle penetrate the user's tissues, the spring actuation means must be dimensioned accordingly and have a significant stiffness constant, leading often with a significant congestion. In addition, the movement of the cartridge relative to the envelope tube requires precise adjustments between their facing surfaces.

 Furthermore, the complexity of the arrangement does not allow easy replacement of the injection cartridge.

 The object of the invention is to propose an injection cartridge allowing a simplification and a lightening of the actuation device thereof and which, moreover, is suitable for easy replacement.

 To this end, the subject of the invention is an injection cartridge of the aforementioned type, characterized in that said front wall is carried by a movable assembly movable relative to the body under the effect of the actuation means between a retracted position in the body, and an active injection position in which the needle projects relative to the body.

According to particular embodiments, the cartridge may have one or more of the following characteristics
- the body comprises a cylindrical tube for guiding the moving element, the moving element comprises a needle holder sliding in a sealed manner against dust and microbes but permeable to air along the inner wall of the tube and the cartridge comprises a second piston interposed between a first piston and the needle and adapted to be perforated by the proximal part of the latter when the first piston is actuated;
- in the retracted position, the needle and the sleeve are essentially received inside the tube
- the needle is covered with a flexible protective sheath carried by the mobile assembly and the end of which is perforable
- The tube contains a first and a second substance separated by a sealed stopper disposed between the two pistons, the cartridge comprising means for mixing the two substances when the first piston is actuated
The invention also relates to a self-injection syringe characterized in that it comprises a bolt bowl in which is received an injection cartridge as defined above, the housing further comprising a spring for actuating the wall. movable rear, maintained in the bandaged state, and means for releasing this spring.

According to particular embodiments, the self-injection syringe may have one or more of the following characteristics
- the housing has a removable end cover which covers the distal end of the cartridge body
- the end cover has internally bearing surfaces of the front end of the cartridge body
- the housing includes a rear cap covering the rear end of the cartridge on the bottom of which the spring bears, the other end of which is applied to the movable rear wall forming a piston, the spring is fitted onto a hollow elongated plunger having, at the front, a pushing surface interposed between one end of the spring and the rear wall of the cartridge and at the rear a split portion provided on its outer periphery with a peripheral retaining lip, the bottom of the cap comprises a through hole in the rear end of the pusher carrying the lip, the latter cooperating with the bottom to hold the compressed spring, and the cap is received mobile in a grip handle, one bottom of which carries the means for releasing the spring, which include a collar for approaching the halves of the pusher retaining lip
- The cap is slidably mounted forward on the body of the cartridge and cooperates with the pusher to actuate the movable rear wall of the cartridge via the spring.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the drawings in which
FIG. 1 is a view in longitudinal section of an injection cartridge according to the invention,
FIG. 2 is a view in longitudinal section of an intermediate portion of the casing of a self-injection syringe according to the invention,
FIG. 3 is a view in longitudinal section of an end cover of the housing of the syringe,
FIG. 4 is a view in longitudinal section of a sliding rear cap of the housing of the syringe,
FIG. 5 is a view in longitudinal section of a plunger of the syringe,
FIG. 6 is a view in longitudinal section of a handle of the housing of the syringe,
FIG. 7 is a view in longitudinal section of a safety pin of the syringe,
FIGS. 8A and 8B are views, respectively in cross section and in longitudinal section along the line VIIIB-VIIIB, of a safety ring of the syringe, and
- Figures 9A to 9E are views in longitudinal section of the complete self-injection syringe shown in successive phases of use.

 The injection cartridge 10 shown in Figure 1 has a substantially cylindrical body 12 made of transparent glass. It has a portion 14 widened by a lateral boss 16. From a rear end, the injection cartridge 10 comprises a movable rear wall 18 formed of a piston whose cylindrical side wall is provided with peripheral ribs in order to ensure the liquid and gas tightness between it and the inner side wall of the tube 12.

 A plug 20 disposed further forward in the tube but behind the enlarged portion 14, defines with the wall 18 a housing 22 for a solvent 24. The plug 20 has on its rear portion peripheral ribs 26 ensuring liquid tightness and to gases with the inner wall of the tube 12. This portion has a length less than that of the boss 16.

 At the front of the stopper 20, at the enlarged portion 14, is disposed a heap of powder 28 containing a medically active substance and which is held against the stopper 20 by a front movable partition 30 identical to the rear movable wall 18.

 A sliding needle holder 32 forming a front wall of the body of the cartridge is disposed beyond the partition 30 towards the front of the tube 12. It is, as shown in FIG. 1, in the retracted position in the tube. The needle holder 32 and the partition 30 define a free space 34 filled with air. The needle holder 32 is formed by a cup 36 made of plastic, the bottom of which is directed towards the partition 30 and the external lateral wall of which carries a helical groove ensuring a seal against dust and microbes between the needle holder 32 and the internal wall of the tube 12, while allowing the air contained in the space 34 to escape to the outside. A semi-sealed sliding connection is thus formed between the sleeve 32 and the tube 12. The bowl 36 has, integrally formed with its bottom, an internal axial stud 38 for fixing an injection needle 40.

 The needle 40 protrudes on either side of the sleeve 36 and is almost completely received inside the tube 12. It has at each of its ends a bevelled front portion 40A and rear 40B. This last end forms a perforation end of the partition 30. A flexible sheath 42 forming a protective cap for the needle 40 completely covers the front portion of the needle. This sheath, produced for example in latex, has a perforable front end 42A opposite the bevelled end 40A of the needle and comprises, at its other rear end, a peripheral bead 44 fitted on the side wall of the axial stud 38.

 In Figure 2 is shown an intermediate piece 50 of the outer housing of a self-injection syringe, an overall sectional view is shown in Figure 9A. This intermediate piece is formed of a tubular section having an inside diameter slightly greater than the outside diameter of the tube 12 of the injection cartridge 10, intended to be fitted inside. On a rear portion 52, the intermediate piece 50 comprises two parallel and diametrically opposite guide grooves 54. These grooves extend longitudinally, parallel to the axis of the part 50 and each comprise at the front a stop notch 55 provided with a ramp of progressively decreasing height towards the rear.

 On the inner wall of the intermediate piece 50, on a front portion 56, are arranged longitudinal ribs 58 for holding the tube 12. On its front end portion, of slightly reduced diameter, the front portion 56 has an external thread 60 adapted to receive a removable end cover 62 of the housing, of generally cylindrical shape, shown in FIG. 3.

 The latter has on its inner side wall a thread 64 adapted to cooperate with the thread 60. A sealing wall 66 at the end of the cover 62 has at its center a weakened or perforated zone 68 for passage of the needle. On its inner wall, the bottom of the cover 62 has axial and radial ribs 70 which extend over the side wall of the cover.

 A cap 72 of the housing, of generally cylindrical shape, shown in FIG. 4, comprises a central well 74 for receiving the rear end of the injection cartridge 10. The well 74, the internal diameter of which corresponds substantially to the external diameter of the tube 12 is closed at the rear by a bottom 76 provided with an axial passage hole 78. At its rear end, the cap 72 externally has four fixing claws 80 extending its lateral surface and provided with hooks 82 oriented towards the outside. On its outer lateral wall, at its front end, it has two studs, 84 diametrically opposite, adapted to cooperate with the guide grooves 54 of the intermediate piece 50. Only one of them is visible in FIG. 4. The cap 72 further comprises in its front portion two diametrically opposite notches 86 opening out towards the front, and formed longitudinally in the cylindrical wall. These notches 86 are angularly offset by 90 "relative to the pins 84.

 In Figure 5, there is shown a hollow pusher 88 of elongated shape traversed right through by an axial duct 91. It has, at a front end, a shoulder 90 forming a pushing surface on the rear wall 18 of the cartridge injection 12. At its rear opposite end, it has a narrowed portion 92 extended by a peripheral lip 94 projecting outwards. This lip 94 has in section a beveled rear portion 94A and a front portion 94B defining a radial shoulder. Longitudinal notches 96, for example two in number, extend from the rear end carrying the lip 94 as far as the narrowed portion 92 and thus delimit two complementary halves of the lip 94. The pusher 88 is made of a semi-material -rigid, for example a plastic material.

 A grip 98 of the casing of the self-injection syringe, covering the rear portion of the cap 72, is shown in FIG. 6.

It has a cylindrical shape. Its rear end carries a closure wall 99 forming the bottom, provided with an axial hole 100 and means 101 for triggering a device for actuating the syringe. These means comprise an axial collar 102 integrally formed with the closure wall 99 on the inner face of the latter.

A second coaxial collar 104 of larger diameter came integrally with the shutter wall 99 on the outer face thereof. This second collar is provided with an external peripheral rim 106. Four notches 108 are distributed over the periphery of the body of the handle 98, at the rear end carrying the closure wall 99, and are adapted to receive the hooks 82 of the claws 80.

 FIG. 7 shows a pin 110 comprising a pointed rod 112 adapted to be received in the axial duct 91 of the pusher 88 through the hole 100 of the handle 98. This rod carries at its rear end a hollow head 114 for gripping and fixing in the form of a bowl, with the bottom of which the rod 112 is made of material. The head 114 has an external peripheral gripping rib 116 and, at the front end of its lateral wall, an external peripheral retaining rib 118 adapted to cooperate with the rim 106 of the handle 98.

 A safety ring 120, shown in FIGS. 8A and 8B, is formed by a section of split tube, the parallel edges of which are extended by radial tongues 124 oriented towards the outside, thus giving it, in section, a shape of n .

 The self-injection syringe according to the invention is shown assembled and in the standby position in FIG. 9A. In order to proceed with its assembly, the blank for receiving the cartridge 10 is first of all formed. Thus, the front end of the cap 72 is introduced into the intermediate part 50 of the box. For this, the ends carrying the pins 84 are brought together by slight deformation of the cap 72 thanks to the notches 86, and are introduced into the guide grooves 54.

 A helical spring 126 is then introduced into the well 74 of the cap 72. The pusher 88 is then fitted into the spring 126. The rear end of the spring 126 is thus supported on the bottom 76 of the cap 72, while its front end rests on the shoulder 90 of the pusher 88. The pusher 88 is then pushed against the spring 126 towards the bottom 76 of the cap 72 until the halves of the lip 94, on approaching, cross the hole of passage 78 and move away again on the other side of the bottom 76 to keep the spring 126 bandaged. The front shoulder 94B of the lip 94 then rests on the bottom 76. The spring 126 and the plunger 88 form means for actuating the syringe.

 The injection cartridge 10 is then introduced into the intermediate piece 50 extended by the cap 72, so that the movable rear wall 18 is in abutment on the shoulder 90 of the pusher 88. The boss 16 of the cartridge is received in one of the notches 86 and is flush with the outside surface of the cap 72.

 The cap 72 is manually held in the extended position of the intermediate piece 50 so that the pins 84 are at the rear end of the guide grooves 54, as shown in FIG. 9A.

 The end cover 62 is then fully screwed onto the thread 60 of the intermediate piece 50 of the housing, until its ribs 70 stop on the end edge of the tube 12. The ribs 70 then form surfaces of support for the front end of the tube 12. The needle 40 is then aligned with the weakened zone 68 of the end cover 62, with its sheath 42 abutting against this zone.

 The handle 98 is then fitted onto the rear portion of the cap 62, until the pins 82 snap into the notches 108. As shown in FIG. 9A, the collar 102 is just in contact with the bevelled portion 94A of the lip 94 of pusher 88.

 The safety pin 110 is then introduced through the through hole 100 of the handle 98 in the central duct of the pusher 88, in order to keep the halves of the lip 94 apart and thus guarantee the maintenance of the spring 126 in the compressed state. . The pin 110 is held on the handle by cooperation of the rim 106 with the rib 118.

 The safety ring 120 is clipped onto the free portion of the cap 72 between the intermediate piece 50 of the housing and the handle 98, thus preventing their coming together.

 It is understood that in this configuration, the self-injection syringe has all its movable elements blocked with respect to each other and can therefore be transported and sold without presenting any risk of accidental tripping.

 When a user wishes to inject himself the active substance contained in the injection cartridge 10, he first removes the safety ring 120, which leads to the configuration shown in FIG. 9B. As has been described with reference to FIG. 1, the self-injection syringe comprises an injection cartridge in which are housed a solvent 24 and a powder 28. Before the injection, the user must mix these two products in order to activate the active substance during a reconstitution phase. To do this, it gradually brings the handle 98 closer to the intermediate piece 50 of a stroke corresponding to the length of the double arrow L1 shown in FIG. 9C. The movement of the handle 98 causes the front portion of the cap 72 to slide. inside the intermediate part 50 of the housing. Thus, the pins 84 move towards the front of the grooves 54 and exceed the stop notches 55 in order to be maintained at the end of movement between the stop notches 55 and the front end of the grooves 54 making the bringing together of the irreversible handle 98 of the intermediate piece 50. During the near rap, the pusher 88, being integral with the bottom 76 of the cap 72 and resting on the movable rear wall 18, causes the elements contained in the tube 12 to move forward. In particular, under the effect of the pressure transmitted by the solvent 24, the sleeve 20 is moved into the enlarged portion 14 (FIG. 9C). The liquid then flows around the sleeve 20 through the boss 16.

The solvent 24 then gradually flows towards the powder 28 and mixes with it. The boss 16 thus forms a portion for bypassing the sleeve 20 and for mixing the two substances 24 and 28.

 As the solvent 24 arrives, the movable partition 30 is pushed back towards the needle holder 32. The air contained in the space 34 gradually escapes through the helical groove formed on the outer peripheral surface of the needle holder 32. To this end, in order to facilitate the flow of air from the front of the tube to the outside, the cover 62 may be provided with very small diameter holes, dustproof, if the spaces between the cooperating threaded and tapped portions do not allow sufficient flow.

 The partition 30 reaching the beveled rear end 40B of perforation of the needle, impaled on the latter, thereby causing the beveled end 40B of the needle to come into contact with the reconstituted active substance formed from the mixture of powder 28 and solvent 24. This position is shown in Figure 9C.

 After reconstitution of the active substance, while the needle holder 32 is still in the retracted position in the body, the safety pin 110 is extracted from the pusher 88, in order to carry out the injection proper, as shown in the figure 9D.

 The end edge of the cover 62 is then applied to the surface of the body where the injection is to be carried out. The operator presses with the hand on the handle 98 in the direction of the intermediate piece 50 of the housing.

The bringing together of these two elements, of a stroke defined by the length of the notches 108, and represented by the double arrow denoted L2 in FIG. 9E, causes the halves of the lip 94 moved apart by progressive insertion of these in the collar 102.

 When the halves of the lip 94 are sufficiently close together, the pusher 88, under the effect of the compressed spring 126, is released from the hole 78. The spring 126 then pushes the pusher 88 and all of the elements contained in the tube 12 towards the end cover 62. The movable assembly formed by the needle holder 32 and the needle 40 proper is thus projected towards the front end of the tube 12. The needle then successively crosses the end 42A of the sheath 42, which abuts against the cover, retracts in an accordion around the needle, then the weakened zone 68 of the cover 62, and finally penetrates into the tissues of the user in the case of a self-injection, or patient, and then protrudes from the cartridge body and the syringe housing.

 Following the progressive decompression of the spring 126 then leads the active substance contained between the sleeve 20 and the front partition 30 to be injected into the user's tissues through the injection needle 40, which leads to the position shown in Figure 9E. This injection step proper takes place very quickly as soon as the spring is released, eliminating any sensation of pain for the user.

 A simple pull back on the syringe allows the user to extract the injection needle from their tissue. The syringe is then discarded.

 It is understood that the displacement of the needle holder and not of the entire injection cartridge, during the actual injection phase, allows the use of a spring having a relatively low stiffness constant and therefore a space requirement and a reduced weight. In addition, the various adjustments between the parts of the syringe external to the injection cartridge can be made relatively roughly, which reduces the manufacturing costs associated with the autoinjection syringe.

 In addition, it will be understood from reading the method of assembling the syringe that the replacement of the injection cartridge, for example in case of expiration of the expiry date thereof, is very easy and is carried out by simple unscrewing the removable end cover 62.

 It should also be noted that the presence of the wall 30 makes it possible to isolate the end 40B of the needle from the injectable products, during the storage phase, which avoids any risk of corrosion of the latter and any chemical interaction between the needle and the powder 28.

 Furthermore, the presence of the grooves 54, associated with the fact that the tube is made of a transparent material, allows visual control through these of the substance after reconstitution.

 In addition, during the entire operating phase of the syringe, namely reconstitution and injection, the spring 126 is constantly kept bandaged or compressed between two bearing surfaces, which guarantees reliable operation of the syringe.

 The embodiment described here includes a phase of reconstitution of the substance to be injected. It is understood, in the case of injection of vaccine for example, that the injection cartridge may contain a single substance which does not require such a reconstitution phase. In this case, the steps leading to the position shown in FIG. 9C are omitted, and the syringe and / or the self-injection cartridge are sold in a state corresponding to that shown in this figure.

 Furthermore, according to another embodiment of the invention, the section of the tube 12 between the rear end of the needle holder 32 and the boss 16 can be extended by a sufficient distance so that at the end of the reconstitution phase, the front partition 30 is located behind the beveled end 40B of the needle and is therefore not yet perforated by the latter.

Under these conditions, after the reconstitution phase, the needle 40 is not in contact with the reconstituted active substance. The perforation of the front partition 30 is carried out, in this embodiment, when the spring 126 is released, and constitutes the first phase of the injection.

 According to yet another embodiment, the tube 10 does not have the boss 16 and the portion of the needle 40 protruding beyond the rear wall of the needle holder sleeve 32 has a length greater than the sum of the thicknesses of the movable front wall 30 and of the plug 20. In addition, the powder mass 28 and the solvent 24 are replaced by two different active injectable liquid substances.

 When the spring 126 is released, the front wall 30 is perforated by the end 40B of the needle and the injectable substance disposed between the latter and the plug 20 is injected into the patient. When the plug 20 reaches the end 40B of the needle, the latter impaled on the latter, and the end of the needle is then brought into contact with the injectable substance disposed between the plug 20 and the wall rear mobile 18. The thrust of the spring 126 then leads to the injection of this second injectable substance. In this embodiment, there is no mixing and reconstitution of the substance to be injected but two different injectable substances are successively injected into the patient.

Claims (10)

 1.- Injection cartridge (10), of the type comprising an elongated body (12) in which is contained a substance to be injected (24, 28) disposed between a front wall provided with an injection needle (40) and a rear wall (18) forming a piston, movable in the body and adapted to be associated with actuating means (88, 126), characterized in that said front wall is carried by a mobile assembly (32) movable relative to the body (12) under the effect of the actuating means (88, 126) between a retracted position in the body (12), and an active injection position in which the needle (40) projects relative to the body (12).  2.- injection cartridge (10) according to claim 1, characterized in that the body comprises a cylindrical tube (12) for guiding the movable element (32), in that the movable element comprises a holder needle (32) sliding in a sealed manner against dust and microbes but permeable to air along the inner wall of the tube (12) and in that the cartridge comprises a second piston (30) interposed between a first piston (18 ) and the needle (40) and adapted to be perforated by the proximal part thereof when the first piston (18) is actuated.  3.- injection cartridge (10) according to claim 2, characterized in that, in the retracted position, the needle (40) and the sleeve (32) are essentially received inside the tube (12).  4.- injection cartridge (10) according to any one of claims 1 to 3, characterized in that the needle (40) is covered with a sheath (42) of flexible protection carried by the moving assembly and the end of which (42A) is perforable.  5.- Injection cartridge (10) according to any one of claims 2 to 4, characterized in that the tube (12) contains a first (28) and a second (24) substances separated by a tight plug (20 ) disposed between the two pistons (18, 30), the cartridge possibly comprising means (14) for mixing the two substances when the first piston (18) is actuated.  6. Self-injection syringe, characterized in that it comprises a housing (50, 62, 72, 98) in which an injection cartridge (10) is received according to any one of the preceding claims, and the housing (50, 62, 72, 98) further comprises a spring (126) for actuating the movable rear wall (18), maintained in the bandaged state, and means (101) for releasing this spring.  7. A self-injection syringe according to claim 6, characterized in that the housing comprises a removable end cover (62) which covers the distal end of the body (12) of the cartridge.  8. A self-injection syringe according to claim 7, characterized in that the end cover (62) has internally bearing surfaces (70) of the front end of the body (12) of the cartridge.  9. A self-injection syringe according to any one of claims 6 to 8, characterized in that the housing includes a rear cap (72) covering the rear end of the cartridge (10) on the bottom ( 76) from which the spring (126) bears, the other end of which is applied to the movable rear wall (18) forming a piston, in that the spring (126) is fitted onto a hollow elongated pusher (88) having, at front, a thrust surface (90) interposed between one end of the spring (126) and the rear wall (18) of the cartridge and at the rear a split portion provided on its outer periphery with a peripheral lip (94 ) holding, in that the bottom (76) of the cap (72) has a hole (78) for passage of the rear end of the pusher carrying the lip, the latter cooperating with the bottom (76) to hold the spring ( 126) compressed, and in that the cap (72) is received movable in a grip handle (98), a bottom (99) of which carries the spring release means (126), which comprise a collar (102) for bringing the halves of the lip (94) holding the pusher (88) closer.  10. Self-injection syringe according to claim 9, characterized in that the cap (72) is slidably mounted forward on the body (12) of the cartridge (10) and cooperates with the plunger (88) for actuating the movable rear wall (18) of the cartridge via the spring.