Removably attachable electronic dose measuring device for injection pen systems

Abstract

A removably attachable dose measuring device for attachment to a proximal end of a syringe pen comprises a distal body having a bore and a central longitudinal axis, adapted to be coaxially mounted on and in rotational engagement with a proximal dose selector wheel of the syringe, the distal body having at least one magnetic field generating element near a proximal end of the distal body, and a proximal dose measuring body including electronic dose measuring circuitry and mounted within the bore of the distal body, the proximal dose measuring body being selectively movable axially along and rotatable about the longitudinal axis, the proximal body having a magnetisable element and including temporary positioning means configured to temporarily maintain a fixed spatial, axial and rotational relationship between the distal and proximal bodies during attachment and removal of the dose measuring device from the syringe.

Description

[Technical field]

[0001] The present invention relates to a removably attachable electronic dose measuring device for an injection pen system. As used herein, the terms "pen injection system" and "injection pen system" are used interchangeably to generally refer to handheld pen-shaped injection systems, such systems being already well known per se and commercially available for use in the treatment of many different medical indications. These systems are generally also often designed for self-injection of the drug by a user who requires treatment for a given medical indication. This is the case, for example, of insulin, which is supplied in various forms for use in the treatment of diabetes, such as pen injection systems commercialized under the brand names FlexPen®, commercialized by Novo Nordisk, Kwikpen®, commercialized by Eli Lilly, or Lantus Solostar®, commercialized by Sanofi, to name just three of the most well-known. Other medications are also used in conjunction with this type of medical device, such as anaphylactic shock treatment, blood thinners, opioid receptor agonists and antagonists, to address potentially life-threatening situations and allow immediate emergency injection of the necessary medication, making it common practice for patients suffering from or susceptible to such diseases to carry these devices with them. [Background technology]

[0002] With regard to injection pen systems in particular, for example, one of the challenges has been to provide an easy to use, reliable and highly fail-safe monitoring and measurement system that can be adapted to the various different types of such pen injection systems available on the market. An injection pen system to which an electronic dose measurement device is adapted and configured for removable attachment typically comprises a proximally located dose setting wheel and an injection actuator. The dose setting wheel rotates about a central longitudinal axis of the pen injection system to allow the user to set the dose of medication for injection. During the dose setting or dose "dial" step, the dose setting wheel is typically rotatable bidirectionally, clockwise and counterclockwise, which directions typically correspond to an increase in the selected dose to be administered and a decrease in the selected dose, respectively, or vice versa, as determined by the manufacturer. The injection actuator, often represented by a push button, is typically located proximally to the dose setting wheel and in many injection pens is located at the proximal end of the injection pen system. After the dose has been set, or "dialed" as the term is commonly known in the art, the user of the injection system then pushes the injection actuator distally, which drives a piston connected to the plunger to expel the medicament from a chamber in the injection pen body through a needle inserted by the user into an appropriate injection site, such as skin, fatty tissue, or muscle, depending on the type of medicament to be administered. The dose setting wheel is sometimes, but not necessarily, also coupled to an injection drive mechanism, depending on the make and model of the injection pen, so that it can also rotate as the injection of the medicament proceeds. The functionality of such injection systems is well known per se in the art. The monitoring module as envisaged by the present invention is intended to be mounted on a pen injection system, in which the dose setting wheel may be configured to rotate during the delivery / injection operation phase of the pen injection system, or conversely, not to rotate during the delivery / injection operation phase.For example, the Kwikpen® injection pen mentioned above does not have a dose setting wheel that rotates during injection, whereas the dose setting wheels on the Lantus Solostar® and FlexPen® injection pens do rotate during injection.

[0003] Injection monitoring and dose measurement, as known per se in connection with injection pen systems, enable users of such pen injection systems, as well as medical personnel involved in the treatment and follow-up of such patients, to more closely monitor the patient's injection regime and in many cases the dose actually administered, leading to better medical outcomes. With these developments has come an associated increase in the use of software and portable communication devices, such as tablets or smartphones, programmed to receive information from and interact with the monitoring and measurement systems in order to provide information to the user or medical personnel, on the fly or at regular intervals, via a suitable communication unit included in the monitoring system. The dose measurement device as envisaged herein is adapted and configured to be removably attached to the proximal end of such an injection pen system. The expressions "removably attached", "removably mountable", "removably mounted" or "removably mountable" as may be used herein should be understood to refer to the attachment or mounting of the dose measuring device and the possibility of subsequently removing or dismounting or disassembling the dose measuring device, for example when transferring the dose measuring device to another pen injection system or if, for example, the dose measuring device is damaged during use and requires replacement. Such attachment and subsequent removal-ability may be achieved by providing the dose measuring device with coupling means that engages with the proximal end of the pen injection system in a releasable manner, for example via frictional or elastic engagement, or via other releasable fastening means such as clips, straps, threads and corresponding clamping rings that engage with either the dose setting wheel or the injection actuator and / or even the body of the injection pen system.

[0004] The applicant has previously filed several patent applications relating to removably attachable electronic dose measuring devices for such injection pen systems, e.g., published as WO2020 / 217076, WO2020 / 217094, and WO2021 / 260404A1. Accordingly, the removably attachable electronic dose measuring devices described in these patent applications may be generally described as configured and adapted to be removably attached to a proximal end of an injection pen having an injection actuation button included at the proximal end of the injection pen for actuating an injection. More specifically, the electronic dose measuring device generally includes the following structures, namely: a distal barrel having a longitudinal bore and a central longitudinal axis, the distal barrel adapted and configured to be coaxially mounted to and in rotational engagement with a proximal dose selector wheel located adjacent to and distal to an injection activation button of the pen injection system, the distal barrel further comprising at least one magnetic field generating element located at or adjacent a proximal end of the distal barrel. a proximal electronic dosage measurement body including an electronic dosage measurement circuit, the dosage measurement body configured to be mounted within the bore of the distal barrel, the electronic dosage measurement body being selectively axially movable along the central longitudinal axis and rotatable about the central longitudinal axis;

[0005] Such a structure then combines an outer, distally disposed body that engages and rotates with the dose setting wheel of the pen injection system during dose setting and / or optionally during dose delivery depending on the specific functionality of the injection pen, with an inner proximal body containing electronic dose measurement circuitry, the inner body typically being rotatable about a central longitudinal axis and selectively movable axially along said central longitudinal axis into the bore of the distal tubular body. The electronic circuitry of the dose measurement body is configured to record changes in the magnetic field as the magnetic field generating element is rotated about the central longitudinal axis during dose setting and / or optionally during dose delivery depending on the specific functionality of the injection pen, and further uses the selective axial movement along the central longitudinal axis to record changes in the magnetic moment along the central longitudinal axis to aid in the determination of other operating conditions such as the start of delivery of medication from the pen injector, the end of delivery from the pen injector, the duration of delivery of substance from the injection pen, etc. In these contexts, selective axial movement refers to actuation of, for example, an injection pen by indirectly pressing a push button of an actuator, via a corresponding button element provided at the proximal end of the proximal electronic dose measurement body, to effect ejection of a substance contained in, for example, a cartridge or chamber included in the pen injection system, which contains, for example, a suitable medicinal substance or other injectable substance. Similarly, when actuation of the push button of the pen injector is terminated, for example by a user releasing finger pressure on the proximal push button of the electronic dose measurement body, the electronic dose measurement body is typically selectively moved in the proximal direction through recoil in the pen injection system or by a return spring provided on the electronic dose measurement body, thereby enabling detection or recording by an electronic circuit of the return of the dose measurement device to its reset position.

[0006] In all of the above, the concepts of proximal and distal refer to relative positions with respect to the entire pen injection system and corresponding removably attachable electronic dose measuring device, where proximal refers to a point, position or direction that generally faces towards the holder of the pen injection system and distal refers to a point, position or direction that generally faces away from the holder of the pen injection system, e.g. towards the target site for injection, whether that be another part of the user's body or the body of another person or animal. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] WO2020 / 217076 [Patent Document 2] WO2020 / 217094 [Patent Document 3] WO2021 / 260404A1 Summary of the Invention [Problem to be solved by the invention]

[0008] The electronic circuitry contained within the proximal electronic dose measurement device can be highly sensitive to unexpected movement when attached to an injection pen system, however the structure of the electronic dose measurement device is designed and configured to manage at least some of these unexpected movement situations when attached to an injection pen.

[0009] However, as has been found through practical use of the above devices, users of electronic dose measuring devices are not always as coordinated as might be expected when loading and unloading the measuring device from the proximal end of an injection pen system. In particular, it has been found in practice that users, by relative movement of either the distal barrel or the proximal electronic dose measuring body, can cause the electronic dose measuring device to inadvertently record in its electronic circuitry an event that may be regarded as the end of an injection or the start of an injection, or some other event such as a failed or incomplete injection. [Means for solving the problem]

[0010] Accordingly, one aspect of the present invention provides a removably attachable electronic dosage measurement device as described above, wherein the selectively movable proximal electronic dosage measurement body includes a temporary positioning means having a magnetisable element, the temporary positioning means being configured to temporarily maintain a fixed spatial relationship, an axial relationship along a central longitudinal axis and a rotational relationship about a central longitudinal axis between the tubular body and the electronic dosage measurement body during attachment and removal of the electronic dosage measurement device to and from the proximal end of an injection pen, and the temporary positioning means being configured to enable the distal tubular body and the proximal electronic dosage measurement body to be maintained in a fixed spatial and rotational relationship to each other while the electronic dosage measurement device is manipulated by a user to attach to and remove from the injection pen.

[0011] According to another aspect, the magnetisable element is magnetised by at least one magnetic field generating element during mounting to and prior to removal from the proximal end of the syringe pen. As used herein, the expression "magnetised by" refers to the magnetisable element being magnetised through magnetic induction of a temporary positioning means caused by the proximity of a magnetic field generating element arranged at or adjacent to the proximal end of the distal barrel to the temporary positioning means during mounting and dismounting of the dose measuring device.

[0012] Similarly, according to yet another aspect, the proximal electronic dosage measurement body is configured to assume a first contracted position in which the magnetizable element is magnetized and a second extended position in which the magnetizable element is no longer magnetized.

[0013] According to a further aspect, in the first contracted position the electronic dosage measuring body is placed in abutting distal surface contact with the proximal surface of the distal tubular body, and in the second extended position the electronic dosage measuring body is moved axially in the proximal direction along the central longitudinal axis and disengaged from distal surface contact with the proximal surface of the distal tubular body.

[0014] From the above, it will be appreciated that the retracted position as envisaged herein is one in which the distal tubular body and the proximal electronic dosage measurement body are, for all intents and purposes, held together in surface-to-surface contact at opposing surfaces of each of the respective bodies by the forces of attraction generated between the magnetic field generating element on the one hand and the induced magnetic field of the temporary positioning means on the other hand, whereas the extended position is one in which said opposing surfaces of the distal and proximal bodies respectively are no longer in surface-to-surface contact but are rather axially spaced apart from one another and the proximal electronic dosage measurement body is disposed proximally of the distal tubular body, more particularly in a position in which the dosage measurement body is free to rotate about its central longitudinal axis.

[0015] Magnetic field generating elements are known per se, for example classical magnets, electromagnets, mixed material magnets. Such magnets are typically made from magnetizable materials that have magnetic or paramagnetic properties, whether naturally or when an electric current or other energy imparting flow passes through or affects said material so as to generate or induce a magnetic field in said material. Suitable materials may be suitably selected from: Ferrite magnets, in particular sintered ferrite magnets, which comprise, for example, a crystalline compound of iron, oxygen and strontium. - A composite material consisting of a thermoplastic matrix and isotropic neodymium-iron-boron powder. - A composite material made from a thermoplastic matrix and a strontium-based hard ferrite powder, where the resulting magnet may contain isotropic, i.e. non-oriented, or anisotropic, i.e. oriented, ferrite particles. - A composite material made from a thermosetting plastic matrix and isotropic neodymium-iron-boron powder. - Magnetic elastomers, produced for example by mixing highly filled strontium ferrite powder with synthetic rubber or PVC and then extruding into the desired shape or calendering into thin sheets. - A flexible calendered composite that generally has the appearance of a brown sheet and is more or less flexible depending on its thickness and composition. These composites are not rubber-like in elasticity and tend to have a Shore hardness ranging from about 40 to about 70 Shore D ANSI. Such composites are generally formed from synthetic elastomers filled with strontium ferrite particles. The resulting magnets can be anisotropic or isotropic, and the various sheets generally have alignment of the magnetic particles due to the calendering process. - Laminated composites, typically comprising flexible composites as described above laminated with soft iron plates. - Neodymium-iron-boron magnets. - Steel made from an aluminum-nickel-cobalt alloy and magnetized. - An alloy consisting of samarium and cobalt.

[0016] Of the above list of magnetic field generating elements suitable for use in the present invention, those selected from the group consisting of neodymium-iron-boron permanent magnets, magnetic elastomers, composites made from a thermoplastic matrix and a strontium-based hard ferrite powder, and composites made from a thermosetting plastic matrix and an isotropic neodymium-iron-boron powder are preferred. Such magnets are known to be capable of being sized to relatively small sizes while maintaining relatively high magnetic field strengths.

[0017] Similarly, in accordance with the selection of the magnetic field generating element, the magnetizable element of the proximal electronic dosing measurement body may be appropriately selected from those specified above, with the difference being that at least initially the magnetizable element is not magnetized, or is magnetized only when it is sufficiently close to the magnetic field generating element so that an induced magnetic field is generated in the magnetizable element. And the magnetic dipole generated in the magnetizable element of the proximal electronic dosing measurement body may be permanent, semi-permanent or temporary, and may be appropriately configured to be maximum when the magnetic field generating element and the magnetizable element are closest in space with respect to the central longitudinal axis, and to be minimum when a certain preconfigured separation distance exists between the proximal electronic dosing measurement body and the distal tubular body is reached. This may be configured by appropriately selecting the corresponding dimensions, size and generated magnetic field of the magnetic field generating element.

[0018] The magnetic field generating element may be of any suitable overall shape, for example a disk, including a circle, an ellipse, or any other suitable polygonal shape, and preferably has only a single dipole with a single pair of diametrically opposed north and south magnetic poles. The magnetic field generating means may also optionally be substantially disk-shaped, and preferably such a disk shape has an opening substantially in the center of the disk and includes a magnet forming a ring or annular magnet. Typically such a ring or annular magnet may be usefully located on the annular proximal-facing peripheral surface of the distal barrel at the proximal end of the distal barrel. Advantageously, for the configurations envisaged herein, the dipole magnets are rod or cylindrical dipole magnets, oriented with opposite poles facing one another, e.g. NS aligned with SN, whereby the magnets are oriented flat along their longitudinal axes which intersect a central longitudinal axis and a horizontal plane which is perpendicular to the central longitudinal axis, with each magnet positioned on opposite sides of said central longitudinal axis, e.g. 180° with respect to rotation about said central longitudinal axis.

[0019] And according to yet another aspect, the magnetisable elements of the proximal electronic dosing body are arranged on a circumferential surface of the electronic dosing body about said central longitudinal axis.

[0020] According to yet another embodiment, the magnetizable element of the proximal electronic dosage measurement body is an annular ring, which may be suitably arranged around the central longitudinal axis on the peripheral surface of the electronic dosage measurement body, for example in an annular circumferential groove in the peripheral wall of the proximal electronic dosage measurement body.

[0021] According to another aspect, the magnetizable element is at least partially arranged on a distal facing peripheral surface of the electronic dosage measurement body. For the sake of understanding, this is taken to mean that the magnetizable element extends at least partially over the distal facing surface of the dosage measurement body. Typically, such a distal facing surface is arranged at or adjacent to the distal end of the dosage measurement body or on the contour or outline of the dosage measurement body having the distal facing surface. In such a configuration, the distal facing surface on which the magnetizable element is arranged is placed opposite a mutually correspondingly placed proximal facing surface of the proximal end of the distal body, e.g. with a substantially longitudinally aligned magnetic field generating element.

[0022] And according to one embodiment, the magnetizable element comprises a distal-facing surface area of ​​magnetizable material, which may suitably comprise magnetizable particles embedded in a suitable polymer or resin matrix, for example, or alternatively, the distal-facing surface area of ​​magnetizable material may be a layer of particles of magnetizable material deposited on the distal-facing surface area or attached to the distal-facing surface area by a suitable adhesive or other technically equivalent means.

[0023] According to yet another aspect, the magnetizable element, most advantageously comprising a distal facing surface area of ​​magnetizable material, is an insert, which may be selected and configured with a shape and size to be physically inserted into the distal facing surface of the dosage measuring body, for example by providing a suitably shaped and dimensioned housing or recess in the distal facing surface area, and which may be retained within the distal facing surface area by any suitable means according to known techniques, for example by mating molding, embedding, etc.

[0024] According to yet another aspect, the insert includes a distally oriented surface extending across the distal facing surface area, the distally oriented surface forming a distal end of the insert.

[0025] Advantageously, according to yet another aspect, the distal end of the insert is disposed flush with the distal facing surface area such that the distally directed surface of the distal end does not protrude distally beyond the distal facing surface area, thus providing a uniform contact surface for mutually opposing contact with the proximal facing surface of the tubular body, more particularly with the proximal facing surface of the magnetic field generating element.

[0026] According to another aspect, the magnetizable insert extends from a first distal end to a second proximal end, the proximal end of the insert being embedded within the electronic dosage measurement body, from which it will be appreciated that the magnetizable insert may extend into or be surrounded by or embedded in a material forming part of the dosage measurement body, or may advantageously be provided by overmolding such material onto the measurement body so that the insert can be recessed therein.

[0027] According to yet another aspect, the magnetizable insert is selected from the group of inserts having an "S", "Z", "C" or "U" shape. Alternatively, advantageously, the magnetizable insert may have a generally annular shape, such as a ring having a corresponding "S", "Z", "C" or "U" shaped cross section or profile. The shape of the insert may be suitably configured and dimensioned depending on the degree of stability and reinforcement desired to provide to the magnetizable element within the dose measuring body.

[0028] According to yet another embodiment, the magnetizable element is located in or on the electronic dosage measurement body in a distal position spaced apart from the electronic circuit. From this it should be understood that the magnetizable element is located at a distance from the electronic circuit within the dosage measurement body such that any magnetic field induced in the magnetizable element does not interfere with or otherwise impede the reading made by the electronic circuit. Configuring the distance from said circuit is one way of achieving this, which may be combined with an appropriate selection of the strength of the magnetic field generating element.

[0029] These and other objects of the present invention will become apparent and will be explained in more detail in the following description of the drawings and exemplary monitoring module.

[0030] The invention will now be described in more detail with reference to the accompanying drawings, given by way of illustration and example, in which: [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic perspective view of a first embodiment of an electronic dosage measurement device in an extended position. [Diagram 2] 2 is a schematic cross-sectional view of another embodiment of an electronic dose measuring device of the present invention mounted on the proximal end of a handheld pen injection system in an extended position; FIG. [Diagram 3] FIG. 3 is a schematic perspective view of a distal facing detail of the electronic dosage measurement device of FIG. 2. [Figure 4] FIG. 4 is a schematic exploded perspective view of a detail of FIG. 3; [Diagram 5] FIG. 5 is a schematic perspective view of a detail of FIG. [Figure 6] FIG. 5 is a schematic perspective open sectional or cutaway view of a detail of FIG. 4. [Figure 7] FIG. 1 is a schematic cross-sectional view of an electronic dosage measurement device in a retracted position. [Figure 8] FIG. 1 is a schematic cross-sectional view of an electronic dosage measurement device in an extended position. [Figure 9] FIG. 2 is a schematic cross-sectional view of an electronic dose measuring device in an extended position after mounting to an injection pen. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] 1 and 2, a schematic diagram of an electronic dose measuring device (1) according to the present invention is shown in a perspective view in FIG. 1 with the dose measuring device in an extended position, and in a cross-sectional view in FIG. 2 with the dose measuring device in a similar extended position. The electronic dose measuring device (1) of FIGS. 2 and 9 is shown mounted or attached to the proximal end (2) of an injection pen (3), and also shows, for example, a dose display window (4), see FIG. 9. The injection pen (3) has an injection activation button (5, see FIGS. 2 and 9) included at the proximal end (2) of the injection pen (3). The electronic dose measuring device (1) includes a distal barrel (6) having a central longitudinal bore (7) and a central longitudinal axis (8). The distal barrel (6) is coaxially mounted to and adapted and configured for rotational engagement with a proximal dose selector wheel (9) located adjacent to and distal to the injection activation button (5). The rotational engagement of the distal barrel (6) with the dose selector wheel is typically achieved through a snap-fit ​​or friction fit of the inner surface (10) of the distal barrel to the outer surface (11) of the dose selector wheel (9) such that any rotational motion imparted to the distal barrel to select an injection dose in the pen injector imparts a corresponding rotational motion to the dose selector wheel about its central longitudinal axis. A pair of NS dipole magnets (13a, 13b) is provided at or near the proximal end (12) of the distal barrel (6) to form a magnetic field generating element. Alternatively, the dipole magnet pair may advantageously be replaced by an annular magnet with a single dipole or multiple pairs of north and south poles, the annular magnet having a central hole aligned with the central longitudinal axis (8) and the central hole (7) of the distal tubular body (6). In Fig. 2 it can be seen that the magnet is located in the hole (7) of the distal body (6) and is mounted in a suitably shaped housing or recess (14a, 14b) which forms an integral part of the distal tubular body (6). A proximal electronic dosage measurement body (15) containing an electronic dosage measurement circuit (16) is at least partially mounted in the hole (7) of the distal tubular body (6).The electronic dosage measurement body (15) is selectively movable axially along the central longitudinal axis (8) and is rotatable about the central longitudinal axis in the extended position shown in Figures 1, 2, 8 and 9.

[0033] The selectively movable proximal electronic dosage-measuring body (15) also includes temporary positioning means (17) configured to temporarily maintain a fixed spatial relationship, axial relationship along the central longitudinal axis, and rotational relationship about the central longitudinal axis between the barrel and the electronic dosage-measuring body during attachment and detachment of the electronic dosage-measuring device to and from the proximal end of the syringe pen. The temporary positioning means (17) is designed to temporarily fix the proximal electronic dosage-measuring body (15) relative to the distal barrel (6) while the electronic dosage-measuring device (1) is mounted to the proximal end (2) of the pen injection system (3). The temporary positioning means (17) thereby enables the proximal electronic dose measurement body (15) to assume a first retracted position in which the magnetizable element is magnetized and in which the proximal dose measurement body (15) is held in abutting distal surface contact with the proximal surface of the distal tubular body (6) relative to the distal tubular dose-setting body (6) by the attractive force of the opposing magnetic poles arranged on the magnetic field generating element on the one hand and on the magnetizable element of the temporary positioning means on the other hand. Furthermore, the temporary positioning means also enables the proximal dose measurement body (15) to assume a second extended position in which the magnetizable element is no longer magnetized and in which the proximal dose measurement body (15) has been moved axially proximally along the central longitudinal axis (8) and disengaged from the distal surface contact of the electronic dose measurement body (15) with the proximal surface of the distal tubular body (6).

[0034] As can be seen from Figures 2, 3, 4, 5 and 6, according to one embodiment, the magnetizable element of the temporary positioning means (17) is an insert (18) having a generally "S" or "Z" shaped profile or cross section (see Figures 2 and 6), arranged around the central longitudinal axis (8) and extending at least partially into and onto the distal facing peripheral surface (19) of the electronic dosage measurement body (15). Alternatively, in another advantageous embodiment (not shown), the magnetizable element comprises a distal facing surface area (19) of magnetizable material, such as a magnetizable paint or particulate material, which may be deposited on or integrated into the distal facing peripheral surface of the dosage measurement body (15). Such a magnetizable element may also be usefully provided as a molded resin matrix containing magnetizable particles. 2 and 5, the insert (18) includes a distally-facing surface (20) extending through a distally-facing surface area (19), the distally-facing surface (20) forming a distal end (21) of the insert (18). The distal end (21) of the insert lies flush with the distally-facing surface area (19) such that the distally-facing surface (20) of the distal end (21) does not protrude distally beyond the distally-facing surface area (19), thereby providing a substantially smooth distal contact surface area for contacting the proximal-facing contact surface (22) of the distal barrel (6). As can be seen from the drawings, the proximal-facing contact surface (22) of the distal barrel (6) comprises the proximal-facing surface of the magnetic field-generating elements (13a, 13b). Prior to mounting the electronic dose measuring device (1) on the injection pen, the proximal dose measuring body (15) is pushed towards the distal cylinder (6), for example by gripping the distal cylinder (6) and the proximal measuring body (15) between the thumb and fingers and bringing the thumb and fingers together. In this way, the distal facing surface area (19) of the dose measuring body (15) and the distal facing surface (20) of the insert (18) are brought into close proximity with the magnets (13a, 13b). The magnetic field generated by the magnets (13a, 13b) induces an opposing attractive magnetic field in the insert (18). The attractive force attracts the opposing surfaces (19, 20, 22) of the proximal measuring body (15) and the distal cylinder (6), respectively, into temporary surface abutment, which corresponds to the retracted position.In this retracted position, the proximal dose-measuring body (15) is no longer free to rotate about the central longitudinal axis (8) and further cannot translate in the direction leading into the bore (7) of the distal barrel (6). At this point, mounting of the measuring device (1) to the proximal end of the injection pen can proceed, knowing that the proximal dose-measuring body will not rotate about the central longitudinal axis (8) and thus will not be able to induce erroneous readings in the electronic circuitry, which may include in particular a magnetometer (23), as known in the art from published PCT applications WO2020 / 217076, WO2020 / 217094. The extended position, in which the mutual surface abutment between the distal barrel (6) and the proximal dose-measuring body (15) and the corresponding magnetic attractive forces are no longer engaged, is obtained by applying a force in the proximal direction to the dose-measuring body (15), thereby overcoming the magnetic attractive forces that held the two bodies together. Such a force may be applied by a user, for example by simply pulling the dose-measuring body along the central longitudinal axis. Alternatively, an actuatable spring-biased element may be provided to assist in moving the proximal dose-measuring body in the proximal direction, such that the proximal dose-measuring body (15) translates axially along the central longitudinal axis to an extended position, the dose-measuring body (15) being again free to rotate about the central longitudinal axis.

[0035] As shown in Figures 2 and 6, the magnetizable insert (18) extends from a first distal end (21) to a second proximal end (24), the proximal end (24) of the insert being embedded within the electronic dosage-measuring body (15). The insert (18) may be shaped and sized and configured to be physically inserted into the distal facing surface area (19) of the dosage-measuring body (15), for example by providing a suitably shaped and sized housing or recess within the distal facing surface area (19), and may be retained within the distal facing surface area (19) by any suitable means, for example by mating molding, embedding, etc. As shown in more detail in Figures 2 and 6, the magnetizable insert (18) extends from the distal end (21) through a central portion (25) to the proximal end (24), the proximal end (24) extending into, surrounded by, or embedded within material forming part of the dosage-measuring body (15). Alternatively, the insert (18) may be provided already integrated into or forming part of an insertable module that is suitably sized and configured to engage and be retained within the measuring body (15) in a push-fit, snap-fit ​​or press-fit engagement.

[0036] Figures 3, 4 and 5 show some of the elements of the dose-measuring body (15), with Figure 3 showing the dose-measuring body upside down with the distal facing surface visible. As can be seen in Figure 3, the dose-measuring body (15) is defined by a circumferential body wall (26) extending from a proximal end (27) to a distal end (28). The distal end (28) of the circumferential body wall (26) is configured to present a diameter that allows it to fit and translate within the bore (7) of the distal barrel (6). The dose-measuring body (15) includes several other elements visible in Figure 3 that relate to the functionality of the electronic circuitry (16), such as a battery holder (29) and corresponding battery (30) for powering the electronic circuitry. FIG. 3 also more clearly shows the distal surface area (19), distal facing surface (20), and distal end (21) of the insert (18), as well as the central portion (25) of the insert (18) extending from the distal end (21) to the proximal end (25), and the planar alignment between the distal surface (20) of the insert (18) and the distal facing surface area (20) of the dosage measuring body (15). As can further be seen from Figure 3, the insert (18) is held within the dosage measurement body by a molded, overmolded or integral hub (31) and spokes (32) structure that includes a central hub (31) disposed about the battery holder (29) from which a series of spokes extend radially outwardly over and / or overlap a portion of the proximal end (24) of the insert, thereby holding and stabilizing the insert within the dosage measurement body (15). Thus, a magnetizable element, here shown as insert (18), is located in or on the electronic dosage measurement body (15) at a distal location spaced from the electronic circuitry (16), the distance being sufficient to ensure that the insert does not interfere with readings performed by the electronic circuitry (16).

[0037] FIG. 4 shows an exploded perspective view of the dose-measuring body (15) in which the electronic circuitry (16) can be seen sandwiched between a distal body part (33) and a proximal body part (34), which may be snap-fit ​​or press-fit, or ultrasonically welded.

[0038] Similarly, FIG. 5 shows an enlarged view of the distal body part (33), illustrating the insert (18) having a distal facing surface (20) and a distal end (21), as well as the distal facing surface area (19) of the respective dosage-measuring body, and further showing the central portion (25) and proximal end (24) of the insert in relation to the hub (31) and spokes (32) which surround and retain the insert (18) within the dosage-measuring body (15).

[0039] Figures 7, 8 and 9, which have the same reference numbers for similar parts of the electronic dose-measuring device (1), show an alternative embodiment in which the temporary positioning means (17) is embodied by an annular ring (17). The annular ring (17) may be a complete ring or a split ring, for example with no end overlap, with a gap between the opposing ends, or with some overlap of the ring ends. The ring (17) is provided on the outer facing surface of the peripheral body wall adjacent the distal end of the dose-measuring body (15) and is seated in an annular circumferential groove (35) defined by the peripheral body wall (26) extending from the proximal end (27) to the distal end (28) of the dose-measuring body (15). The annular ring is made of magnetisable material in the same or similar manner as the insert 18 and functions in the same manner as the insert 18 with regard to the relative movement of the distal tubular dose-setting body 6 and the proximal electronic dose-measuring body 15, as well as the movement to a retracted position for loading and unloading the device from the injection pen, and to an extended position when the dose-measuring device is loaded into the injection pen. The main difference in this embodiment is that the magnetisable surface of the ring 18 does not come into direct contact with the proximal facing surface 22 of the magnets 13a, 13b, even though in the retracted position the distal facing surface area 19 is in contact with said proximal facing surface 22.

Claims

1. 1. A removably attachable electronic dose measuring device configured and adapted to be removably attached to a proximal end of an injection pen having an injection activation button included at the proximal end of the injection pen for activating an injection, comprising: a distal barrel having a longitudinal bore and a central longitudinal axis, the distal barrel being coaxially mounted to a proximal dose selector wheel located adjacent to and distal to the injection activation button, the distal barrel being adapted and configured for rotational engagement with the proximal dose selector wheel, the distal barrel including at least one magnetic field generating element located at or adjacent a proximal end of the distal barrel; a proximal electronic dosage measurement body including an electronic dosage measurement circuit, the dosage measurement body configured to be mounted within the bore of the distal barrel, the electronic dosage measurement body being selectively movable axially along the central longitudinal axis and rotatable about the central longitudinal axis; the selectively movable proximal electronic dosage measurement body includes temporary positioning means having a magnetizable element, the temporary positioning means being configured to temporarily maintain a fixed spatial relationship, an axial relationship along the central longitudinal axis, and a rotational relationship about the central longitudinal axis between the tubular body and the electronic dosage measurement body during attachment and detachment of the electronic dosage measurement device to and from the proximal end of the syringe pen. A removably attachable electronic dose measuring device.

2. 2. A removably attachable electronic dosage measuring device as described in claim 1, wherein the proximal electronic dosage measuring body is configured to assume a first contracted position in which the magnetizable element is magnetized and a second extended position in which the magnetizable element is no longer magnetized.

3. 4. A removably attachable electronic dosage measuring device as described in claim 3, wherein in the first contracted position, the electronic dosage measuring body is placed in abutting distal surface contact with the proximal surface of the distal tubular body, and in the second extended position, the electronic dosage measuring body is moved axially in a proximal direction along the central longitudinal axis and disengaged from distal surface contact of the electronic dosage measuring body with the proximal surface of the distal tubular body.

4. 4. A removably attachable electronic dosage measuring device according to claim 1, wherein the magnetizable element is magnetized by the at least one magnetic field generating element during attachment to the proximal end of the syringe pen and before removal from the proximal end of the syringe pen.

5. A removably attachable electronic dosage measuring device as described in any one of claims 2 to 4, wherein the magnetizable elements of the proximal electronic dosage measuring body are arranged around the central longitudinal axis on a circumferential surface of the electronic dosage measuring body.

6. A removably attachable electronic dosage measurement device according to any one of claims 2 to 5, wherein the magnetisable element of the proximal electronic dosage measurement body is an annular ring.

7. 7. A removably attachable electronic dosage measuring device according to claim 6, wherein the annular ring is disposed within an annular circumferential groove provided in a peripheral wall of the proximal electronic dosage measuring body.

8. A removably attachable electronic dosage measuring device according to any one of claims 2 to 7, wherein the magnetisable element is arranged and positioned at least partially on a distal facing peripheral surface of the electronic dosage measuring body.

9. 9. A removably attachable electronic dosage measuring device according to any one of claims 2 to 8, wherein the magnetisable element comprises a distal facing surface area of ​​magnetisable material.

10. 10. A removably attachable electronic dosage measuring device according to any one of claims 2 to 9, wherein the magnetisable element comprising a distal facing surface area of ​​magnetisable material is an insert.

11. 11. A removably attachable electronic dosage measuring device according to claim 10, wherein the insert includes a distally oriented surface extending across the distal facing surface area, the distally oriented surface forming a distal end of the insert.

12. 11. A removably attachable electronic dosage measuring device as described in claim 10, wherein the distal end of the insert is positioned flush with the distal facing surface area such that the distally directed surface of the distal end does not protrude distally outward beyond the distal facing surface area.

13. A removably attachable electronic dosage measurement device as described in any one of claims 10 to 12, wherein the magnetizable insert extends from a first distal end to a second proximal end, the proximal end of the insert being embedded within the electronic dosage measurement body.

14. A removably attachable electronic dosage measuring device as claimed in any one of claims 10 to 13, wherein the magnetisable insert is selected from the group of inserts having an "S", "Z", "C" or "U" shape.

15. A removably attachable electronic dosage measurement device as described in any one of claims 2 to 14, wherein the magnetizable element is located within or on the electronic dosage measurement body at a distal position spaced from the electronic circuit.

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