WO2001074423A1

WO2001074423A1 - Injection syringe for extemporaneous mixture

Info

Publication number: WO2001074423A1
Application number: PCT/FR2001/000896
Authority: WO
Inventors: Yves Arnissolle
Original assignee: Sedat
Priority date: 2000-03-31
Filing date: 2001-03-23
Publication date: 2001-10-11
Also published as: FR2806916B1; AU4841901A; FR2806916A1

Abstract

The invention concerns a syringe for injecting an extemporaneous mixture comprising a tubular reservoir (16, 62, 66) containing at least two substances (36, 38) initially separated by an intermediate plunger (32) and means (18, 30) for mixing the two initially separated substances to form the extemporaneous mixture. The mixing means (18, 30) comprise a mobile internal partition (30) inside the tubular reservoir (16, 62, 66) along a travel path for preparing the extemporaneous mixture. The mobile partition (30) is adapted to ensure the flow in the tubular reservoir (16, 62, 66) of at least one substance (36) to enable the two substances to be mixed. It comprises means (90, 106) limiting the speed of the movement of the mobile internal partition (30) along the preparation travel path.

Description

The present invention relates to a syringe for injecting an extemporaneous mixture, of the type comprising a tubular reservoir containing at least two substances initially separated by an intermediate piston and means for mixing the two substances initially. separated to form the extemporaneous mixture, which mixing means comprise a movable partition inside the tubular reservoir following a course of preparation of the extemporaneous mixture, the movable partition being adapted to ensure the circulation in the tubular reservoir of at least a substance for the purpose of mixing the two substances.

Such a syringe is described in particular in document EP-A-0.219.899 with reference to FIGS. 14 and 15.

In this document, the syringe comprises an injection cartridge received in a syringe housing. This cartridge constitutes a tubular reservoir in which the substances to be injected are retained. These are initially separated by movable pistons. The means for mixing the substances are formed by a lateral projection of the cartridge. This locally increases the internal section of the cartridge and delimits a passage allowing the substances to bypass the separating pistons. Means for automatic actuation of the rear wall for injection are also provided in the housing. They essentially comprise a pusher loaded by a spring and means for releasing the pusher.

In order to ensure the reconstitution of the extemporaneous mixture, at least part of the syringe housing is movable relative to the cartridge, so that, when the housing is manually caused to slide on the cartridge, the pusher requests the movable rear partition of the cartridge and moves it towards the front partition thus leading to the mixing of the substances to be injected by passing them through the boss. After mixing the substances to be injected, the spring of the actuating means is released, which causes the automatic injection of the premixed substances. In such a syringe, the mixing is ensured by axial displacement along a rectilinear path of a part of the housing bearing on the rear partition relative to the injection cartridge.

In practice, it is found that, if the operator exerts a very large force on the movable part of the body of the syringe, in order to cause the preparation of the extemporaneous mixture, the force thus applied transmitted through one of the substances to injecting into the movable intermediate piston causes the latter to move suddenly in the syringe body and exceed the lateral boss allowing the piston to be bypassed. The intermediate piston, having thus crossed the lateral boss, constitutes a barrier preventing the circulation of the substances to be mixed. The extemporaneous mixing is then not carried out or is carried out only in an incomplete manner, so that its concentration in the various constituents initially contained in the cartridge is poor. The effect of this dysfunction is all the more noticeable since self-injection syringes are commonly used in crisis situations where a single person has to inject into himself. The stress then leads the user to act violently on the syringe. The object of the invention is to propose a solution to this problem, thus avoiding that the extemporaneous mixing is only carried out incompletely before injection.

To this end, the invention relates to a syringe of the aforementioned type, characterized in that it comprises means for limiting the speed of movement of the movable partition according to the preparation stroke. According to particular embodiments, the syringe comprises one or more of the following characteristics:

the movable partition is slidably mounted inside said tubular reservoir along a rectilinear path defining the preparation stroke, and it comprises means for actuating the movable partition for its displacement along the rectilinear path, which means of actuation are movable relative to the tubular reservoir along a path comprising at least one section winding around the direction of the rectilinear path of movement of said movable partition; - Said path of movement of the actuating means relative to the tubular reservoir describes a helix around the direction of the rectilinear path of movement of the movable partition;

- The actuating means and the tubular reservoir include complementary threads;

- The preparation run corresponds to a number of turns of the complementary threads between 1 and 4 and preferably substantially equal to 2;

the actuating means and the tubular reservoir comprise complementary elastic latching means ensuring the securing of at least part of the actuating means and the tubular reservoir after the displacement of the movable partition along its preparation race;

- the actuation means can be moved manually relative to the tubular reservoir; and

- Said actuating means comprise automatic means for ejecting the extemporaneous mixture from the tubular tank in order to carry out the injection.

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:

- Figure 1 is a sectional view of a syringe according to the invention;

- Figure 2 is a longitudinal sectional view of the tube of the cartridge of the syringe of Figure 1; - Figure 3 is a sectional view on a larger scale of the region of the tube of the injection cartridge where are formed bypass passages of the intermediate piston initially separating the substances to be injected;

- Figure 4 is a cross-sectional view of the tube of the injection cartridge taken along the line I V-1 V of Figure 3;

- Figure 5 is a longitudinal sectional view of the intermediate sleeve of the body of the syringe; - Figure 6 is a longitudinal sectional view of the rear cover of the syringe body;

- Figure 7 is a longitudinal sectional view of the syringe during the initiation of the reconstitution phase of the extemporaneous mixture; - Figure 8 is a longitudinal sectional view of the syringe at the end of the reconstitution phase of the extemporaneous mixture; and

- Figure 9 is a longitudinal sectional view of the syringe after injection.

A self-injection syringe 10 is shown in FIG. 1 in its initial state corresponding to its state of storage before use. It comprises an injection cartridge 12 according to the invention and an external housing 14 in which the cartridge is mounted.

The injection cartridge 12 comprises a substantially cylindrical tube 16. The interior surface of the tube is generally cylindrical with a circular section. In its median part, the tube has a median section 18 where its inner surface has a profile delimiting at least one flow passage allowing the extemporaneous mixing of two initially separate substances contained in the tube.

The median section 18 is bordered on either side by sections with a smooth cylindrical inner surface devoid of projecting or hollow profiles.

As illustrated in Figures 2 to 4, the section 18 has a set of ribs 20 extending parallel to each other along generatrices of the tube. These ribs 20 protrude from the inner cylindrical surface of the tube. They define between them parallel channels 22 forming passages for the flow of a fluid.

The ends of the ribs facing the rear of the tube have a chamfer 24 visible in FIG. 3.

The ribs are distributed regularly over the inner periphery of the tube.

Two successive ribs are spaced approximately 18 ° apart. The height of each rib is of the order of 0.3 mm, the diameter of the tube being approximately 12 mm. These ribs are approximately 8.5 mm long. The tube 16 is advantageously made of injected plastic. To do this, a mold is used which defines a generally cylindrical cavity. Along the axis of the cavity are initially arranged two cylindrical pins placed end to end. These pins form a core capable of delimiting the tubular conduit formed inside the tube 16. One of the pins has at its end grooves extending parallel to each other along generatrices. These grooves are adapted to form the ribs 20 formed on the interior surface of the tube 16.

While the two pins forming the core are arranged in the cavity, molten plastic is injected into the mold. For the removal of the two pins, each of them is pulled along the axis of the tube from one end of the latter. The tube thus formed can be removed from the mold cavity.

It will be appreciated that the profiles making it possible to define the passage channels 22 being protruding profiles, the manufacture of the tube 16 is very simple to carry out since no insert comprising radially movable parts must be used.

From a rear end, the injection cartridge 12 comprises a movable partition 30 forming a piston, the cylindrical lateral surface of which is provided with peripheral ribs in order to ensure the liquid and gas tightness between it and the interior lateral surface of the tube 16.

An intermediate piston 32 is disposed further forward in the tube but behind the section 18. It defines with the partition 30 a housing 34 for a solvent 36. The intermediate piston 32 has on its lateral surface peripheral ribs in order to sealing the liquids and gases with the inner surface of the tube 16. This piston has a length less than that of the ribs 20.

At the front of the intermediate piston 32, at the level of the section 18, is disposed a mass of powder 38 containing a medically active substance. It is held against the intermediate piston 32 by a front movable partition 40 identical to the rear movable partition 30. The piston 32 and the partition 40 thus initially define a chamber 41 for confining the powder 38. The powder mass 38 can be replaced by a liquid substance. A sliding needle holder 42 forming a front wall of the cartridge is disposed beyond the partition 40 towards the front of the tube 16. It is shown in FIG. 1 in the retracted position in the tube. The needle holder 42 and the front partition 40 define a free space

44 filled with air. The needle holder 42 is formed by a cup 46 made of plastic, the bottom of which is directed towards the front partition 40 and the lateral wall of which has a helical groove 48 on the outside ensuring a seal against dust and microbes between the needle holder 42 and the inner surface of the tube 16, while allowing the air contained in the space 44 to escape towards the outside. A semi-sealed sliding connection is thus formed between the needle holder 42 and the tube 16. The cup has, integrally formed with its bottom, an internal axial stud 50 for fixing an injection needle 52. The needle 52 protrudes on either side of the bowl 46. It is initially completely received inside the tube 16. It has at its ends a front beveled tip 52A and a rear beveled tip 52B. This last end forms a perforation end of the front partition 40. The housing 14 essentially comprises a body 60, formed of a front cover 62 and a rear cover 64, connected to each other by an intermediate sleeve 66, a grip handle 68 movable relative to the body 60, automatic means 70 for actuating the movable rear partition of the cartridge for injection, and means 72 for releasing the actuation means 70.

The front cover 62 is permanently connected to the intermediate sleeve 66. Together with the tube 16 of the cartridge which rests on the front cover 62, they form a tubular reservoir of the syringe relative to which the rear cover 64 is movable in order to move the rear partition 30 following a course of preparation of the extemporaneous mixture.

The front cover 62 comprises a tubular section 74 having externally longitudinal ribs facilitating the gripping. Its inside diameter is greater than the outside diameter of the tube 16. The cover of 62 comprises a sealing wall 76 in the center of which is formed a passage 78 for the injection needle. The front end of the tube 16 is supported axially on the sealing wall 76. Between them is interposed a perforable membrane 80 initially ensuring the isolation of the needle 52 from the external environment.

On the inner surface of the tubular section 74, the front cover has an internal thread 82 to which the intermediate sleeve 66 is screwed.

This intermediate sleeve, shown alone in FIG. 5, has a generally tubular shape. Its internal diameter is constant and corresponds substantially to the external diameter of the cartridge 12.

At its front end oriented towards the injection needle 52, the intermediate sleeve 66 has an external thread 84 adapted to cooperate with the thread 82, formed internally in the front cover 62. At its rear end, the intermediate sleeve 66 has legs 86 elastically deformable, these legs being naturally biased towards the outside. The legs 86 are distributed along the periphery of the intermediate sleeve 66.

At their end, these legs 86 have protrusions 88 on their outer face.

In its main part and over most of its length, the sleeve 66 has a thread 90 whose direction of the threads is the same as that of the threads of the thread 84.

The thread pitch 90 is large. Thus, for example, the helical thread forming the thread 84 is wound over three turns along the length of the sleeve 66.

Between the two threads 84 and 90, the intermediate sleeve 66 has a peripheral stop 92 for translational locking of a ring 94 for removable safety locking. The rear cover 64, shown alone in FIG. 6, is formed by a tubular section 100 whose rear end is partially closed by a bottom 102 having a central passage 104. The tubular section 100 a a nominal inside diameter substantially equal to the outside diameter of the intermediate sleeve 66.

At its open end opposite the bottom 102, the rear cover 64 has internally a thread 106 adapted to cooperate with the thread 90 formed on the outer surface of the intermediate sleeve 66. This thread is formed by a helical groove formed in the thickness of the cover . This helical groove has a pitch equal to the pitch of the thread 90. It is wound over 360 ° along the threaded length of the cover.

The complementary threads 90 and 106 constitute means limiting the speed of movement of the rear partition 30 during the reconstitution of the extemporaneous mixture, as will be described in the following text.

Behind the thread 106, the rear cover 64 internally has a first peripheral groove 108 adapted to receive the projections 88 provided at the ends of the legs 86 when the syringe is in its initial state.

In addition, a second peripheral groove 110 is formed on the inner cylindrical surface of the cover 64 slightly in front of the bottom.

102. This second groove 110 is adapted to receive the projections 88 of the legs 86 and thus immobilize the intermediate sleeve axially at the end of reconstitution of the extemporaneous mixture.

As shown in Figure 1, the cartridge 12 is received inside the housing 14 and is held between, at the front, the sealing wall 76 and, at the rear, the actuating means 70 of the rear piston of the cartridge.

These actuating means 70 essentially comprise an actuating spring 112 in which is disposed a pusher 114. The latter comprises a rod 116 provided at its front end with a pad 117 for bearing on the rear partition of the cartridge. The rod 116 is extended externally by two elastic tongues 118 extending substantially parallel. These tongues each carry at their end an outer lip 120 having in section a beveled rear portion 122 and a front front 124 defining a shoulder- radial. The tongues 1 18 are in the initial state engaged through the central passage 104 so that the radial shoulders 124 bear on the bottom 102 and thus maintain the spring 112 bandaged.

The grip 68 is essentially formed by a sleeve 130 completely surrounding the rear cover 64. This sleeve has in its rear part centripetal radial pins 132 received in an outer peripheral groove 134 formed around the rear cover 64. The groove 134 has, along the axis of the rear cover, a width greater than the corresponding width of the pins 132. These are thus free to move axially along a stroke defined by the two lateral edges of the groove, the latter forming stops .

The handle 68 is closed by a wafer 136 screwed to the rear end of the sleeve 130. The wafer 136 is, in the initial state, kept at a certain distance from the bottom 102. The wafer 136 has a central duct 138 in which are partially engaged the beveled ends of the lips 120. The duct 138 gradually widens towards its end facing the lips 120.

The handle 68 has on its inner surface at least one flat cooperating with the corresponding flat formed on the bottom 102 of the rear cover 64 in order to secure the rotation of the handle and the rear cover.

A safety pin 150 is engaged in the initial state through the central duct 138 so that its end extends between the tongues 118 and keep them spaced from one another. The spindle 150 came integrally with a cup 152, covering the rear end of the grip 68.

In order to proceed with the assembly of the self-injection syringe shown in FIG. 1, the rear cover 64 is first fitted into the grip handle 68 and then the wafer 136 is fixed. Then introduced inside the cover rear 64 the actuating spring 112 and the pusher 114, so that the lips 122 of the tongues 118 pass through the central passage 104 and that the radial shoulders 124 of these apply against the bottom 102 of the rear cover. Pin 150 is then inserted between the tongues 118, to guarantee their spacing and thus prevent the accidental release of the spring 112.

The intermediate sleeve 66 is then screwed into the rear cover 64 by engaging the complementary threads 90 and 106. The screwing takes place until the projections 88 are received in the first groove 108 of the rear cover. In this position, the threaded section of the rear cover 64 extends in the rear part of the thread 90 formed along the length of the intermediate sleeve.

The safety ring 94 is then placed between the stop 92 and the open end of the handle 68.

The actuating means 70 being immobilized, the complete cartridge 12 is placed in the intermediate sleeve 66. The front end of the cartridge is then capped by the front cover 62 provided with the membrane 80. The cover 62 is then screwed on the intermediate sleeve 66, thus ensuring their final connection.

It is understood that in this configuration, the self-injection syringe has all of 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 the active substance contained in the injection cartridge 12 into himself, he removes the safety ring 94.

As illustrated in FIG. 7, after removal of the safety ring 94, the intermediate sleeve 66 can be pushed inside the rear cover 64 by screwing. To this end, the front cover 62 is actuated manually in the direction of the arrow F7. It drives the sleeve 66 to which it is linked.

During the screwing, the tube 16, in abutment on the front cover 62, is moved axially relative to the rear cover 64. The partition 30 which is held in abutment on the pusher 114, itself immobilized with respect to the rear cover 64, is thus progressively inserted along a rectilinear path inside the tube 16, the latter being moved towards the rear of the syringe. Due to the presence of the liquid 36, the intermediate piston 32 is also immobilized relative to the rear cover 64.

The insertion of the tube 16 into the rear cover 64 leads to a relative displacement between the intermediate piston 32 and the tube 16. Thus, the piston 32 is brought into the section 18 of the tube. Simultaneously, the powder 38 and the front partition 40 are moved further forward in the tube. The engagement of the intermediate piston 32 in the section 18 is facilitated by the presence of the chamfers 24 forming ramps. These allow a radial deformation of the intermediate piston 32. This deformation leads to a centripetal compression of the piston which causes a reduction in its diameter. Thus, once engaged in the section 18, the intermediate piston leaves free the channels 22 defined between the ribs 20.

Continued screwing allows the fluid 36 contained in the chamber 34 to flow towards the powder 38 by passing through the channels 22 defined between the ribs 20.

Gradually, during screwing, the rear partition 30 is pressed into the tube along a course of preparation for the extemporaneous mixture. It thus drives the liquid 36 beyond the intermediate piston 32, the latter remaining immobilized in the section 18 of the tube. The arrival of the liquid between the intermediate piston 32 and the front wall 40 causes the front wall 40 to move towards the front of the tube.

As the liquid 36 arrives, the movable partition 40 is pushed back towards the needle holder 42. The air contained in the space 44 gradually escapes through the helical groove 48 formed on the outer peripheral surface of the needle holder 42. To this end, in order to facilitate the flow of air from the front of the tube towards the outside, the cover 62 can be provided with very small diameter holes if the spaces between the threaded portions cooperants do not allow sufficient flow.

To ensure complete transfer of the substance 36 into the chamber containing the powder, the rear cover 64 is screwed on for about two turns. Advantageously, this screwing takes place over a number of turns between 1 and 4. At the end of the screwing, as illustrated in FIG. 8, the rear partition 30 reaches the end of its stroke for preparing the extemporaneous mixture. It is then in contact with the intermediate piston 32 while the front partition 40 extends immediately behind the tip 52B of the needle. In this position, almost all of the liquid 36 initially retained in the chamber 34 is transferred between the intermediate piston 32 and the front partition 40.

The presence of the complementary threads formed between the tubular reservoir containing the substances to be injected and the movable part of the body of the syringe consisting of the rear cover 64 and the grip handle 68, allows the reconstitution to be obtained by a screwing movement. During this screwing, the rear partition 30 moves on a rectilinear path following its course of preparation of the extemporaneous mixture. Due to the screwing movement imposed by the presence of the complementary threads, the translational movement of the rear partition is slowed down in relation to an axial sliding movement between the reservoir of the syringe and the movable part of the syringe body ensuring moving the rear bulkhead. Indeed, due to the manipulation necessary for screwing the two moving parts of the syringe, the operator is forced to perform relatively slowly the reconstitution of the extemporaneous mixture.

Thus, the risks of seeing the intermediate piston 32 accidentally cross the mixing section 18 under the action of too high pressure are eliminated.

In order to carry out the injection proper, the operator removes the safety pin 150 which initially prohibits the bringing together of the tongues 118.

As illustrated in Figure 8, the front end of the syringe is pressed against the area of the body where the injection is to be performed. The operator then presses the grip handle 68 forward. Thus, the wafer 136 acts on the elastic tongues 118 and leads to the approximation of the lips 120. When the latter are sufficiently close together, the pusher 114 is released from the passage 104 under the effect of the compressed actuating spring 122. This spring then pushes the pusher 114. The latter acts on the elements contained in the tube 16 and causes them to move towards the needle 52. In particular, the front partition 40 reaching the tip 52B of the needle, impaled on the latter, causing thus bringing the needle into contact with the reconstituted active substance formed from the mixture of powder 38 and liquid 36. The needle holder 42 is then projected towards the front end of the tube 16. The needle 52 then passes through the membrane 80 and then enters the user's tissues.

Following progressive relaxation of the actuating spring 112 leads the active substance contained between the intermediate piston 32 and the front partition 40 to be injected into the user's tissues through the injection needle 52. At the end injection, the syringe is in the position shown in Figure 9. The injection step itself takes place very quickly as soon as the spring is released, eliminating any sensation of pain for the user. The invention has been described here in the context of a self-injection syringe, but it can also be implemented in a syringe with manual actuation. In this case, the actuation means of the rear partition formed by the pusher 114 and the actuation spring 112 are eliminated and replaced by a simple manual actuation rod. In the embodiment described here, the means limiting the speed of movement of the rear partition 30 along its stroke for preparing the extemporaneous mixture are formed of threads arranged between the two movable complementary parts of the syringe, thus imposing a helical movement between these two pieces. The propeller pitch is constant here. However, as a variant, this pitch is variable depending on the length of the propeller.

As a variant, the displacement between the two complementary parts of the syringe body ensuring the displacement in translation of the rear partition 30 can be of any other nature insofar as it comprises at least one section along which the relative displacement takes place at least partially by rotation around the direction of movement of the rear partition 30.

In particular, this path may comprise two rectilinear sections extending in the direction of movement of the rear partition 30, these two sections being connected by a section of relative displacement in rotation of the two moving parts of the syringe body.

In addition, the relative movement path of the two complementary parts of the syringe may comprise a succession of movements of the two parts relative to each other along sections of the propeller having alternating winding directions.

According to a variant embodiment not shown, the means making it possible to limit the speed of movement of the rear partition 30 comprise a set of pinions meshed with one another and actuated under the by the piston 30 in movement. The presence of this set of pinions creates significant friction opposing the rapid displacement of the rear partition 30.

Claims

CLAIMS 1.- Syringe for injecting an extemporaneous mixture, of the type comprising a tubular reservoir (16, 62, 66) containing at least two substances (36, 38) initially separated by an intermediate piston (32) and means ( 18, 30) of mixing the two substances initially separated to form the extemporaneous mixture, which mixing means (18, 30) comprise a partition (30) movable inside the tubular reservoir (16, 62, 66) following a stroke for preparing the extemporaneous mixture, the movable partition (30) being adapted to ensure the circulation in the tubular tank (16, 62, 66) of at least one substance (36) with a view to mixing the two substances, characterized in that it comprises means (90, 106) for limiting the speed of movement of the movable partition (30) along the preparation stroke, in that the movable partition (30) is slidably mounted inside said tank tubular (16, 62, 66) next t a rectilinear path defining the preparation stroke, in that it comprises actuating means (64, 114) of the movable partition (30) for its displacement along the rectilinear path, which actuating means (64, 114 ) are movable relative to the tubular reservoir along a path comprising at least one section winding around the direction of the rectilinear path of movement of said movable partition (30), and in that the preparation stroke corresponds to a number of turns complementary threads (90, 106) between 1 and 4 and preferably substantially equal to 2.

2. A syringe according to claim 1, characterized in that said path for moving the actuating means (64, 114) relative to the tubular reservoir (16, 62, 66) describes a helix around the direction of travel. rectilinear movement of the movable partition (30).

3. A syringe according to claim 2, characterized in that the actuating means (64, 114) and the tubular reservoir (16, 62, 66) include complementary threads (90, 106).

4.- Syringe according to any one of the preceding claims, characterized in that the actuating means (64, 114) and the tubular reservoir (16, 62, 66) comprise elastic engagement means complementary (88, 1 10) ensuring the joining of at least a part (64) of the actuating means (64, 114) and the tubular tank (16, 62, 66) after the displacement of the movable partition (30) following its preparation run.

5.- Syringe according to any one of the preceding claims, characterized in that the actuating means (64, 114) are moved manually relative to the tubular reservoir (16, 62, 66).

6. A syringe according to any one of the preceding claims, characterized in that said actuating means (64, 114) include automatic means (112) for ejecting the extemporaneous mixture from the tubular reservoir (16, 62, 66 ) in order to proceed with the injection.