Patent Application
20250213793
The present invention relates to a medical device for automatic injection of a product in a safe way, especially in emergency situations.
Some illnesses necessitate regular injections of drugs or products, for instance on a daily basis. In order to simplify the treatment, some self-injectors have been provided in order to allow the patient to perform the injection on his/her own.
Since the patient is usually neither a nurse nor an educated person in medical devices, such self-injectors must prove to be very simple to use and also very safe. In particular, the insertion of the needle must be performed at the right depth, the correct dose of product must be injected, that is to say a complete injection must be performed, and the injector must be deactivated after use before it is disposed of. Preferably, the needle should not be exposed, before and after use, in order to prevent any accidental needlestick injury.
Another important requirement of these self-injection devices is that they must not be able to be activated inadvertently, before the patient is ready to perform the injection, and in particular before the device is correctly applied at the right injection site.
Some automatic injection devices comprise a safety shield adapted to cover the needle tip except during injection, and a button to be pressed by the patient to trigger the injection.
The documents EP 2 921 191, WO 2021/067210 A1, US 2019/374728 A1 and WO 2009/040672 A2 disclose such an automatic injection device.
Before use, the safety shield and the needle are covered by a cap and the button is locked in order to avoid any accidental activation. The device comprises a mechanism configured to unlock the button once the safety shield has been pushed sufficiently onto the patient's skin.
Thus, the injection requires three actions from the user:
However, when a drug has to be administered to the patient in an emergency situation, this three-step injection process may be too long or complex. For example, if a patient suffers from anaphylaxis, adrenaline has to be administered very quickly in order to avoid patient's death.
Thus, there is a need for self-injection devices that could be activated in a minimized number of steps without deteriorating the safety of the device. In particular, as indicated above, the device must not be able to be activated inadvertently and it also must avoid any accidental needlestick injury.
The present invention meets this need by proposing a device for automatic injection of a product into an injection site, comprising:
Thanks to the cooperation between the cam and the plunger retainer, only two actions—which are: (1) removing the cap and (2) pressing the safety shield onto the patient's skin—are required from the user to fully perform the injection.
Thus, the ergonomics of the device is improved. Such improved ergonomics is in particular beneficial in emergency situations since it simplifies the operation of the device and may reduce the time required to inject the full dose to the patient.
In the present text, the distal end of a component or of a device is to be understood as meaning the end furthest from the user's hand and the proximal end is to be understood as meaning the end closest to the user's hand. Likewise, in the present text, the distal direction is to be understood as meaning the direction of injection, and the proximal direction is to be understood as meaning the opposite direction to the direction of injection.
In the present text, the term “axial” designates a direction parallel to the direction of injection (the direction of injection also corresponding to a longitudinal axis of the injection device) and the term “radial” designates a direction perpendicular to the direction of injection.
In some preferred embodiments, taken alone or in combination if appropriate:
The terms Fig., FIG., Figs., FIGS., Figure, FIGURE, Figures, and FIGURES are used interchangeably to refer to the corresponding figures in the drawings.
Further features and advantages of the invention will be disclosed in the following detailed description, based on the appended drawings, wherein:
Unless otherwise specified, the components of the injection device are represented in their initial position, before use of the injection device. However, as will be explained below, some of the components are movable in translation and/or in rotation relative to each other to perform the injection. Thus, the description will refer not only to the initial position of the components, but also to one or more operative positions or phases that are reached during the injection process.
To summarize, before use, the body of the injection device is closed by a cap which protects the inside of the injection device from the outside environment.
In a first step, the cap is removed. As a result, the injection device is in an initial position. In said initial position, exposure of the needle and injection of the product are prevented by the fact that the needle and the medical container containing the product for injection are housed within the body of the injection device and that the plunger rod is locked in translation by a plunger retainer.
In a second step, to perform an injection, a safety shield is applied onto the patient's skin at an injection site. The safety shield is thus caused to translate in the proximal direction, which causes a cam coupled to the safety shield to rotate until a plunger retainer unlocks a plunger rod.
Said unlocking of the plunger rod triggers a continuous injection phase in which the plunger rod pushes a stopper in the distal direction. As a result, a medical container engaging the stopper is caused to translate in the distal direction-thereby allowing the needle to pierce the patient's skin at the right injection depth. Further, the movement of the stopper in the medical container in the distal direction expels the product from the medical container into the patient's body.
The device 1 comprises a housing 10 comprised of an upper body 11 and a lower body 12 that may be rigidly connected to each other.
The housing 10 has an outer shape adapted to be held in a user's hand. In general, the outer surface of the housing 10 is intended to be gripped by the palm and the fingers of the user's hand.
The connexion of the upper and lower bodies can be a snap-fit connection, screw-type connection, bayonet connection, or other means of connecting two parts together, in an unreleasable way or not. When the device is of a single use type, the means for connecting the upper body to the lower body are made unreachable to the user.
A cap 13 is removably connected to a distal end of the housing 10. The cap 13 can be connected to the lower body 12 by a snap-fit connection or by any other type of connection allowing removal of the cap 13 by an axial movement in the distal direction.
A medical container 20 such as, for example, a syringe, is received in at least one of the upper and lower bodies 11, 12.
As shown in
As shown in
Before use (see
Returning to
The upper body has a generally cylindrical shape and is open at both ends. The distal end is connected to the lower body. The upper body further comprises an inner cylinder 14 (see
A plunger rod 40 for causing the stopper to move with respect to the medical container 20, as will be explained later, is received within the upper body 11, more precisely within the inner cylinder 14.
The plunger rod 40 comprises a shaft 41 provided at its distal end with a flange 42 and a tip 43 adapted to engage the stopper. The proximal end of the shaft comprises an anti-rotation portion 44 and a toothed disk 45 extending proximally relative to the anti-rotation portion. The shaft 41 may comprise one or more axial rib(s) designed for increasing its stiffness.
As shown in
The toothed disk 45 comprises a plurality of teeth 450 extending radially outwardly and distributed in a regular manner about the axis of the plunger rod.
A first spring 49 is arranged around the shaft 41 of the plunger rod, the distal end of the spring 49 bearing onto the flange 42 and the proximal end of the spring 49 bearing onto an inner surface of the proximal end 16 of the inner cylinder 14 of the upper body 11. In the initial position, the spring is in a compressed state. As a result, the spring 49 urges the plunger rod 40 in the distal direction. However, in the initial position, the plunger rod is locked by a plunger retainer 80 and thus is prevented from translating in the distal direction.
The plunger retainer 80 is pivotally mounted in the upper body 11, in a proximal portion of said upper body. As shown in
The central opening 83 of the plunger retainer comprises a plurality of teeth 831 extending radially inwardly.
The central opening 83 extends proximally from the opening 17 of the inner cylinder of the upper body.
In the initial position (see
However, the teeth 831 of the plunger retainer and the teeth 450 of the plunger rod as designed to be substantially complementary in shape, i.e. the recesses 830 between the teeth 831 of the plunger retainer 80 substantially fit the teeth 450 of the plunger rod 40, or are greater than said teeth 450 so that the toothed disk 45 of the plunger rod is able to pass through the opening 83 when the teeth 450 of the plunger rod are axially aligned with a corresponding recess 830 between teeth 831 of the central opening 83.
Otherwise said, in some angular positions of the plunger rod relative to the plunger retainer, the plunger rod is locked in distal translation by the plunger retainer (as shown in
Of course, any other non-circular shapes of the proximal end of the plunger rod and of the plunger retainer could be used, provided that they are complementary.
The skirt 81 of the plunger retainer is provided with at least one distal leg 84, preferably two legs diametrically opposite to each other. The function of said legs will be explained in more detail below.
As shown in
The ring 50 comprises at least one finger 53 protruding radially from the rigid portion 51. Preferably, the ring comprises two fingers 53 diametrically opposite to each other.
The lower body forms a housing which receives at least partially the medical container 20 and the ring 50. As will appear later, the medical container 20 is movable relative to the lower body between an initial position, in which the tip of the needle does not extend beyond the distal end of the lower body, and an injection position, distally spaced relative to said initial position and in which the tip of the needle extends beyond the distal end of the lower body and is exposed over a predetermined length.
The lower body has a general cylindrical shape and is open at both ends. As shown in
The lower body comprises at least one axial groove 15 receiving a respective finger 53 of the ring 50. Preferably, the lower body has two axial grooves 15 diametrically opposite to each other, and the ring has two fingers, each received in a respective axial groove. As will be explained in more detail below, such axial groove serves as a guide for axial movement of the ring (and the container) relative to the lower body. Advantageously, said groove is located in a proximal portion of the lower body 12, which is covered by the upper body 11; thus, the groove 15 and the finger 53 are not accessible by a user from the outside of the injection device.
The injection device also includes a safety shield 60 that is at least partially received within a distal portion of the lower body. As shown in
The distal end of the safety shield 60 is advantageously provided with a radial flange 63 forming a bearing surface for applying the injection device onto the patient's skin, the width of the flange being chosen so as to distribute the pushing force on a sufficiently large surface for not injuring the patient.
The safety shield is coupled to a cam 70 pivotably mounted in the lower body 12.
As shown in
The cam 70 presents at least one first groove 71, preferably two first grooves diametrically opposite to each other.
Each first groove 71 comprises an inclined (i.e. non-axial) first branch 71a and an axial second branch 71b connected to the first branch at a proximal end of both branches 71a, 71b. Otherwise said, each first groove has the shape of number “1”.
Each lug 62 of the safety shield slidingly engages a respective first groove 71 in the cam 70.
In the initial position, the lug 62 is located at the distal end of the first branch 71a (see
When the lug 62 reaches the proximal end of the first branch 71a and engages the second branch 71b, the plunger retainer unlocks the plunger rod, as will be explained below.
A second spring 65 is arranged between the proximal end of the rigid portion of the ring 50 and the flange 64 of the safety shield. In the initial position, the second spring 65 may be in a relaxed state, but a movement of the safety shield 60 in the proximal direction compresses the second spring 65. As a result, if the user releases the pressure applied onto the injection device, the second spring 65 urges the safety shield 60 in the distal direction.
The cam 70 further comprises at least one second groove 72 (preferably two second grooves 72 diametrically opposite to each other). Each second groove 72 comprises a proximal portion 72a extending perpendicular to the direction of injection and a distal portion 72c parallel to the proximal portion, and an inclined (i.e. non-axial) portion 72b connecting the proximal portion 72a to the distal portion 72c. Otherwise said, the proximal and distal portions 72a, 72c of each second groove are spaced both in the axially and angularly. The axial distance between the proximal portion 72a and the distal portion 72c of the second groove 72 is equal to the penetration depth of the needle within the patient's body.
The ring 50 is at least partially received within the cam with each finger 53 of the ring being in sliding engagement within a respective second groove 72.
In the initial position, each finger 53 of the ring is in the proximal portion 72a of the respective second groove 72.
As shown in
The functioning of the injection device 1 will now be explained.
The injection device is provided to a user ready-to-use, with the cap closing the distal end of the body.
The medical container is filled with a predetermined dose of an injectable product-preferably a single dose thus providing a one-time use or disposable injection device.
Prior to use, the user removes the cap and the needle shield, without rotation of said needle shield. The injection device is thus in its initial position.
The user then places the safety shield against the patient's skin at an injection site. The patient may be the user or another person.
As the device is pressed against the patient's skin, the safety shield is caused to move in the proximal direction and into the lower body.
Due to the above-described safety features, the user cannot activate the device (i.e., cause the container to move from its initial position to its injection position and cause the plunger to push the stopper within the barrel) until the safety shield is caused to move a predetermined distance in the proximal direction so as to allow the plunger retainer driven by the cam to unlock the plunger rod
When the device is pressed against the patient's skin and the safety shield is moved out of its initial position in the proximal direction until the plunger rod is unlocked, the device is automatically activated to begin an injection.
This unlocking of the plunger rod causes the plunger rod to push the stopper in the distal direction. Said movement of the stopper thus causes a movement of the whole medical container in the distal direction from its initial position to its injection position, which also causes the needle to pierce the patient's skin.
Then, the plunger rod is still pushing the stopper in the distal direction in the barrel, which causes the injectable product to automatically be expelled from the container and into the patient's skin.
It is to be noted that, once the plunger retainer is in the suitable position for unlocking the plunger rod, the unlocking of the plunger rod, the movement of the stopper and of the medical container happen during a continuous injection phase, without any further action from the user. In addition, the second position of the safety shield and the unlocking position of the cam are not stable positions but merely intermediate (temporary) positions reached during the triggering of the injection device.
Once the injection is complete, the user removes the device from the injection site and the safety shield is caused to automatically extend from the lower body to cover the now-contaminated tip of the needle. Advantageously, even if the user removes the device from the injection site before the injection is complete, the safety shield will automatically extend over the tip of the needle. Once the injection device is removed from the injection site and the safety shield is extended over the tip of the needle, the shield is locked in place and cannot thereafter be moved from its locked position in the proximal direction to expose the tip of the needle. The used injection device is thus rendered safe for handling and disposal.
The triggering of the injection device thus requires only one action from the user after the cap has been removed.
Referring to the figures, when the user applies the injection device on the injection site by means of the bearing surface 63 of the safety shield 60, a distal force is exerted on the lower body 12 thereby causing the safety shield 60 to move relative to said lower body from the initial position, to a second position in which the plunger retainer driven by the cam unlocks the plunger rod, the second position of the safety shield being proximally spaced relative to said initial position.
During this proximal translation of the safety shield 60 to its second position, each lug 62 translates along the inclined branch 71a of the cam 70, thereby causing the cam 70 to rotate until the connection with the axial branch 71b, which corresponds to the unlocking position of the cam.
If the user releases the pushing force before reaching the second position, the compressed second spring 65 causes the safety shield to move back to the distal position in order to protect the needle.
The rotation of the cam 70 is transmitted to the plunger retainer via the legs 84. The angular displacement of the plunger retainer is chosen so as to align the teeth of the plunger rod with the recesses between the teeth of the opening 83 of the plunger retainer, thereby allowing the toothed disk 45 to pass through the opening 83.
As a result, the plunger rod 40 is caused to move in the distal direction under the distal force of the spring 49.
The distal end 43 of the plunger rod 40 engages the stopper and pushes it in the distal direction. The stopper which is in frictional engagement with the barrel thus causes the whole medical container to move in the distal direction. Since the medical container is supported by the ring 50, the ring 50 is caused to translate in the distal direction with the medical container. During said translation, the fingers 53 of the ring 50 move within the second groove 72 of the cam. More precisely, each finger 53 engages the inclined portion 72b of the respective second groove 72, until the finger 53 reaches the distal portion 72c of the second groove, which prevents any further movement of the ring 50 and the medical container in the distal direction. Said translation of the ring 50 causes the cam 70 to further rotate, which allows the lug 62 to engage the second branch 71b of the first groove 71.
The medical container has thus reached its injection position. In this position, the needle protrudes from the distal end of the lower body 12 and pierces the patient's skin. As noted above, the axial stroke of the finger 53 between the proximal and distal portions 72a, 72c of the second groove 72 of the cam 70 defines the penetration depth of the needle. This ensures that the product be injected at the right depth between the patient's body.
The plunger rod continues pushing the stopper to expel the product from the barrel through the needle until the stopper reaches the distal end of the barrel.
Once the injection is completed, the user withdraws the injection device from the patient's skin.
This withdrawal causes the second spring 65 to push the safety shield 60 in the distal direction, the lugs 62 sliding within the second branch 71b of the first groove 71 of the cam 70, until a final position in which the safety shield covers and protects the needle. When in said final position, the safety shield is locked against proximal movement thereby preventing unintended access to the contaminated needle.
The injection device is thus very easy to use, even in emergency situations, and very safe since it prevents accidental needlestick injuries even in case said device is removed from the injection site before the injection of the product is actually completed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22305376.0 | Mar 2022 | EP | regional |
This application is the United States national phase of International Application No. PCT/EP2023/057615 filed Mar. 24, 2023, and claims priority to European Patent Application No. 22305376.0 filed Mar. 25, 2022, the disclosures of which are hereby incorporated by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/057615 | 3/24/2023 | WO |
