Various means for producing a magnetic field are known, for example, classical magnets, electromagnets, and mixed material magnets. Such magnets are typically made from magnetizable materials, having magnetic or paramagnetic properties, whether naturally or when an electric or other energizing flow traverses or affects said material to produce or induce a magnetic field in said material. Suitable materials can be appropriately selected from:

- ferrite magnets, especially sintered ferrite magnets, for example, comprising a crystalline compound of iron, oxygen and strontium;
- composite materials consisting of a thermoplastic matrix and isotropic neodymium-iron-boron powder,
- composite materials made up of a thermoplastic matrix and strontium-based hard ferrite powder, whereby the resulting magnets can contain isotropic, i.e. non-oriented, or anisotropic, i.e. oriented ferrite particles;
- composite materials made of a thermo-hardening plastic matrix and isotropic neodymium-iron-boron powder,
- magnetic elastomers produced with, for example, heavily charged strontium ferrite powders mixed with synthetic rubber or PVC, and subsequently either extruded into the desired shape or calendered into fine sheets;
- flexible calendered composites, generally having the appearance of a brown sheet, and more or less flexible depending on its thickness and its composition. These composites are never elastic like rubber, and tend to have a Shore Hardness in the range of about 40 to about 70 Shore D ANSI. Such composites are generally formed from a synthetic elastomer charged with strontium ferrite grains. The resulting magnets can be anisotropic or isotropic, the sheet varieties generally having a magnetic particle alignment due to calendering;
- laminated composites, generally comprising a flexible composite as above, co-laminated with a soft iron-pole plate;
- neodymium-iron-boron magnets;
- steels made of aluminium-nickel-cobalt alloy and magnetized;
- alloys of samarium and cobalt.

Of the above list of magnetic field producing means suitable for use in the present invention, those selected from the group consisting of neodymium-iron-boron permanent magnets, magnetic elastomers, composite materials made up of a thermoplastic matrix and strontium-based hard ferrite powder, and composite materials made of a thermo-hardening plastic matrix and isotropic neodymium-iron-boron powder, are preferred. Such magnets are known for their ability to be dimensioned at relatively small sizes whilst maintaining relatively high magnetic field strength.

Whilst the magnetic field producing means can be of any suitable general shape, for example disk-shaped, including circular, ellipsoid, or any other suitable polygonal shape, it preferably has only a single dipole, with a single pair of diametrically opposing north and south magnetic poles. Although the magnetic field producing means can also optionally be substantially disk-shaped, such a disk-shape can also preferably include magnets which have an orifice substantially in the centre of the disk to form a ring or annular shaped magnet. Such a ring or annular shaped magnet can usefully be seated on a peripheral annular and proximal facing surface of the hollow main body at the proximal extremity thereof.

According to yet another object, the hollow main body further comprises translational abutment means adapted and configured to prevent axial translational movement of the inner sleeve along the central longitudinal axis, when the injection monitoring module is in the mounted position on the injection pen system. The translational abutment means are shaped and dimensioned to prevent axial translational movement of the inner sleeve, beyond a predetermined point inside the hollow main body, along the central longitudinal axis in at least a distal direction, but also advantageously and preferably in a proximal direction along said central longitudinal axis.

According to yet another object, the translational abutment means of the hollow main body are formed as an annular groove or annular slot provided on an inside surface of the hollow main body.

According to a still further object, the translational abutment means are formed from a distally oriented surface provided on the hollow main body, and a respectively proximally oriented surface of the distal body portion, whereby the distally oriented surface and said proximally oriented surface together form a cooperating translational abutment surface for said inner sleeve.

According to another object, the inner sleeve further comprises surface engagement means located adjacent to, or substantially at, a distal extremity of said inner sleeve, wherein said surface engagement means are configured to engage with at least an inner surface of a distal body portion of the hollow main body and thereby prevent translational movement of the inner sleeve in a distal and/or proximal direction, when the injection monitoring module is in the mounted position on the injection pen system.

According to yet a still further object, the surface engagement means comprise at least one continuous projection, or a plurality of separate projections, extending radially outwardly from an outer surface of said inner sleeve.

Advantageously, and according to yet another object, the surface engagement means comprise at least one distally oriented surface, and said distally oriented surface of the surface engagement means engages with a respectively proximally oriented surface of a translational abutment means provided on an inside surface of the hollow main body.

According to yet a further object, the surface engagement means comprise at least one continuous projection, or a plurality of separate projections, extending radially outwardly from an outer surface of said inner sleeve. and the translational abutment means of the hollow main body are formed as an annular groove or annular slot provided on an inside surface of the hollow main body, wherein said annular groove or annular slot is adapted and dimensioned to receive in cooperating proximal and distal surface engagement said at least one continuous projection, or a plurality of separate projections, extending radially outwardly from an outer surface of said inner sleeve.

To summarize the above, the translational abutment means of the hollow body, and the surface engagement means of the inner sleeve, are provided with appropriately shaped surfaces and areas that cooperate with each other to prevent any translational movement in either the proximal or the distal direction, when the hollow main body is mounted on the body of the pen injection system.

According to yet another object, the inner sleeve further comprises at least one, or a plurality, of elastically deformable surfaces extending inwardly towards the central longitudinal axis from said inner sleeve, forming at least one, or a plurality, of frictionally engaging surfaces to frictionally engage with an outer surface of the dose setting wheel.

According to still another object, the at least one, or plurality, of elastically deformable surfaces extending inwardly towards the central longitudinal axis from said inner sleeve is a ring of elastically deformable material comprising a plurality of coaxially aligned, radially spaced apart teeth, extending in a same direction from said ring, and said ring is seated at a proximal extremity of the inner sleeve, with the teeth oriented to extend in a distal direction, along an outer and/or inner surface of said sleeve. Advantageously, the elastically deformable material is a suitable elastomer, such as a SEBS elastomer.

According to yet another object, the inner sleeve further comprises a plurality of coaxially aligned, radially spaced apart, openings traversing the inner sleeve from an outer surface to an inner surface thereof.

Advantageously, and according to another object, the at least one, or plurality, of elastically deformable surfaces extends through the radially spaced apart openings traversing the inner sleeve.

As will be readily understood from the preceding paragraph, the elastically deformable surfaces advantageously extend from one side, for example, an outer surface, of the inner sleeve, through the body material of the inner sleeve, and through to the other side, for example, an inner surface of the inner sleeve.

According to yet another object, the inner sleeve further comprises at least one injection monitoring system connection surface extending from an inner surface of the sleeve and projecting inwardly towards the central longitudinal axis of the bore.

Advantageously, and according to a yet further object, the at least one injection monitoring system connection surface extending from an inner surface of the sleeve and projecting inwardly towards the central longitudinal axis of the bore comprises at least one, or a plurality of, recesses provided in said inwardly projecting connecting surface.

According to yet another object, the injection monitoring system comprises a housing, and said injection monitoring system housing comprises at least one connection surface extending from said housing in a distal direction.

According to a yet still further object, the at least one injection monitoring system connection surface and the at least one injection system housing connection surface are adapted and configured to engage mutually with each other in a first position in which rotation of the injection monitoring system housing causes co-rotation of the inner sleeve, and to engage with each other in a second position in which the injection monitoring system only translates along the central longitudinal axis in a distal or proximal direction, without rotation of the injection monitoring system housing around said central longitudinal axis.

As will be readily understood from the above, the at least one injection monitoring system connection surface and the at least one injection system housing connection surface engage respectively one with the other. In the first position, the respective surfaces engage with each other to rotate together about the central longitudinal axis, for example, when a dose is being set, and in the second position, the at least one injection system housing connection surface translates against the at least one injection monitoring system connection surface in a distal, or proximal direction, depending on whether the activation button is being pressed or respectively released.

According to a further object, the at least one connection surface extending from said injection monitoring system housing comprises at least one, or a plurality of, distally extending projections, extending from a distal extremity of the housing and aligned coaxially with the central longitudinal axis.

According to yet another object, in the first position, the at least one, or plurality of, distally extending projections of the injection monitoring housing each comprise an outwardly facing connection surface which frictionally engages with a corresponding inwardly facing surface of the at least one, or plurality, of recesses provided in said inwardly projecting connecting surface.

According to a still further object, in the second position, the at least one, or plurality of, distally extending projections extending from said injection monitoring system housing further comprise at least one distally oriented contact surface which is in contact with the injection activator.

In a still further object, the injection monitoring system is further configured to determine a time elapsed during which the injection monitoring system is in physical contact with pen activator, for example, the pen activator push button, of the pen injection system.

The magnetic field production means is provided so that the magnetic field sensor will detect any changes in magnetic field, for example, due to rotational movement of the inner sleeve relative to the magnetic field producing means, during dose setting, thereby enabling the dialed dose set via the dose setting wheel to be determined. Furthermore, during injection, when digital pressure in a distal direction along the central longitudinal axis is being exerted on the housing of the injection monitoring system, the magnetic field sensor will detect changes in magnetic field due to the sensor translating along the longitudinal axis in a distal direction towards the magnetic field production means, and then in a reverse, proximal direction, as digital pressure is released from the injection monitoring system.

The magnetic field sensor is thus used to measure the magnetic field produced by the magnetic field producing means. Movement of the magnetic field sensor around the central longitudinal axis relative to the fixed hollow body proximal extremity positioning of the magnetic field production means, as the dose wheel is rotated, via the inner sleeve in contact therewith, is used to calculate or determine a dose of injectable substance in the injection pen system that has been dialed or set by the user. Once the dose has been set, activation of the proximal activator button leading to translational movement of the injection monitoring system housing, and correspondingly housed magnetic field sensors provided therewith, along the central longitudinal axis, is used to determine or calculate whether an injection has begun. Conversely, and respectively, when finger or thumb pressure on the proximal activator button is released, the recoil energy inherent in the injection pen causes the pen injection activator button to recoil, inducing translational movement of the injection monitoring system housing along the central longitudinal axis in a proximal direction, towards the thumb or fingers of the user, thereby also moving the magnetic field sensors housed within the injection monitoring system in the proximal direction. The change in magnetic field signals that the magnetic field sensors detect, when moving in this way, is processed by the injection monitoring system to determine a corresponding end of injection or ejection operation. The processing of the signals generated for begin and end of injection enables a determination of the dose actually injected between the injection begin signal and injection end signal to be made.

Means for measuring magnetic fields to determine are known generally in the art. For example, magneto-resistors are a well known means. Such magneto-resistors are often designated by their abbreviations, e.g. AMR, GMR, TMR sensors, which designate the physical mechanisms by which these sensor components function. Giant magnetoresistance (GMR) is a quantum mechanical magnetoresistance effect observed in thin-film structures composed of alternating ferromagnetic and non-magnetic conductive layers. Anisotropic magnetoresistance, or AMR, is said to exist in materials in which a dependence of electrical resistance on the angle between the direction of electric current and direction of magnetization is observed. Tunnel magnetoresistance (TMR) is a magnetoresistive effect that occurs in a magnetic tunnel junction (MTJ), which is a component consisting of two ferromagnets separated by a thin insulator. Resistors that use these various properties are known per se.

In light of the above, the injection monitoring module and/or system according to the invention preferably uses one, or more, or a plurality of magnetometers as the one, more or plurality of magnetic field sensors. Such magnetometers differ from the GMR, AMR or TMR sensors in that it directly measures magnetic field strength. Magnetometers measure magnetic fields in two main ways: vector magnetometers measure the vector components of a magnetic field, and total field magnetometers or scalar magnetometers measure the magnitude of the vector magnetic field.

Another type of magnetometer is the absolute magnetometer, which measures the absolute magnitude or vector magnetic field, using an internal calibration or known physical constants of the magnetic sensor. Relative magnetometers measure magnitude or vector magnetic field relative to a fixed but uncalibrated baseline, and are also called variometers, used to measure variations in magnetic field.

A preferred type of magnetometer therefore for use in the injection monitoring module according to the present invention is an ultra low-power high performance three axis Hall-effect magnetometer. Whilst it is possible for the magnetometer to be configured to measure magnetic field over three mutually perpendicular or orthogonal axes, it is preferred in the present case that the magnetic field sensors be configured to measure magnetic fields over just two of the three orthogonal axes, for example the X and Z axes.

According to yet another object of the invention, the injection monitoring system comprises an electronic component board.

Advantageously, and according to a further object of the invention, the one or more or plurality of magnetic field sensors are electrically connected to the electronic component board. The one or more magnetic field sensors can helpfully be located on the electronic component board in diametrally opposed positions or otherwise radially distributed on the electronic component board, around the central longitudinal axis, and preferably, a single magnetic field sensor is located on the central longitudinal axis.

Even more advantageously, the electronic component board comprises an integrated control and data processing unit, such as at least one micro-controller, connected electrically to the one or more, or plurality, of magnetic field sensors, for processing information received from the magnetic field sensors. The electronic component board can therefore suitably be, for example, a printed circuit board of correspondingly appropriate dimensions. In the configurations envisaged in the present invention, such a printed circuit board is advantageously disk-shaped, with its centre corresponding to the point of intersection with the central longitudinal axis.

The electronic component board is advantageously housed within a housing that is located proximally of the hollow main body, and preferably within an injection monitoring system housing that is located beyond the proximal extremity of the central bore. Additionally, and advantageously, the electronic component board is held such that a horizontal plane of the component board is located in a plane substantially orthogonal to said central longitudinal axis. The electronic component board is further located in a fixed rotational relationship in a first position, for example during dose setting, with the inner sleeve, so that rotation of the hollow main body causes the electronic component board to rotate in synchronised movement, matching that of the inner sleeve. This means that when the inner sleeve is rotated, the at least one or more or plurality of magnetometers located on the electronic component board also rotate around the central longitudinal axis. The fixed rotational relationship of the injection monitoring system to the inner sleeve in the first position can be ensured via any suitable coupling established between the inner sleeve and the injection monitoring system in said first position, as for example, has been described hereabove in regard to the coupling formed by the at least one injection monitoring system connection surface and the at least one injection system housing connection surface.

The integrated control and data processing unit, comprising at least one micro-controller, handles all electrical communication and signalling between the different electronic components of the electronic component board and the magnetic field sensors. It is also responsible for execution of the calculations enabling the precise positional location of the magnetic field sensor to be calculated and determined, as well as handling signals from an autonomous power supply and communication means integrated into the injection monitoring system, and which communicate with a local or remote data processing system, e.g. on a smartphone. Such integrated control and data processing units are known per se, and often integrate a central processing unit, a real time clock, one or more memory storage systems, and optionally communications systems or subsystems, along with other desired components.

According to yet another object of the invention, the electronic component board comprises a communications unit in electrical connection with the at least one microcontroller. Such a communications unit can be one or more of any number of communications units known per se, such as a wireless communications unit, for example, Bluetooth®, Bluetooth LE® or any other short or long range wireless communication technologies.

According to still further object of the invention, the electronic component board comprises an autonomous, and optionally rechargeable, power supply, for example a lithium ion battery, which can be easily exchanged when depleted, or alternatively, a rechargeable battery, such as a rechargeable lithium ion battery. In the event that a rechargeable battery is provided, said rechargeable battery can be charged up when depleted via a corresponding charging port, such as a USB charging port, provided in the injection monitoring module and connected to the rechargeable battery. Both non-rechargeable, i.e. single-use batteries and rechargeable batteries are generally known per se to the skilled person. Advances in charging technology have today also made wireless charging a reality, and such a wirelessly chargeable battery, for example, using an induction charging system, is also foreseen as a possibility within the objects of the invention.

These and other objects of the invention will become apparent and described in more detail in the following description relating to the figures and an example monitoring module.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described in more detail with regard to the accompanying figures, provided for the purpose of illustration and exemplification, in which:

FIG. 1 is a schematic perspective representation of an injection monitoring module mounted on a handheld pen injection system;

FIG. 2 is a schematic cross-sectional representation of the injection monitoring module of FIG. 1 mounted on a handheld pen injection system;

FIG. 3 is a schematic perspective representation of the injection monitoring module of FIG. 1 or FIG. 2;

FIG. 4 is a schematic, axial representations of the injection monitoring module of FIG. 1 or FIG. 2, seen from a distal extremity thereof, along a central longitudinal axis of the module;

FIG. 5 is a schematic, perspective exploded view of the injection monitoring module of FIG. 1 or FIG. 2;

FIGS. 6A and 6B are schematic, cross-sectional representations of the injection monitoring module of FIG. 1 or FIG. 2 in a first and second position about the central longitudinal axis in a dose setting position;

FIG. 7 is a schematic, cross-sectional representation of the injection monitoring module of FIG. 1 or FIG. 2, in a dose ejecting or administering position;

FIG. 8 is a schematic, perspective view of an injection monitoring system housing forming part of the injection monitoring module of FIG. 1 or FIG. 2, and also represented in FIG. 5.

DETAILED DESCRIPTION OF AN EXAMPLE

Turning now to FIGS. 1 and 2, a schematic perspective representation of an injection monitoring module (1) according to the invention is shown. The injection monitoring module (1) is mounted on a handheld injection pen system (2), which comprises a pen injection system body (3) having an outer peripheral surface (4), a pen cap (5) covering the distal extremity of the pen injection system, a dose setting or dialling wheel (6), located at the proximal extremity of the pen injection system body (3), and a dialed dose visualisation window (7), located distally of the dose setting wheel (6), and displaying the dose which has been dialed by a user of the pen injection system. The injection monitoring module (1) according to the invention is located and adjacent to the proximal extremity (8) of the injection pen system (2), in particular at least partly around and in contact with the peripheral outer surface (4), surrounding and in contact with the pen body (3) and extending in a proximal direction beyond the proximal extremity (8) of the pen body (3) and in particular beyond the dose setting wheel (6). A central longitudinal axis (9) is also illustrated, which traverses the longitudinal axial centre of both the injection monitoring module (1) and the injection pen system body (3). The injection pen system is provided with an activator button (10) proximally located from the dose setting or dialling wheel (6), as can be found in several commercially available injection pen systems. In the type of pen injection system displayed in FIGS. 1 and 2, the dose setting wheel is rotated about the central longitudinal axis (9) during dose setting, but is fixed against rotation during injection. An example of such a pen is available under the FlexTouch® insulin injection pen range supplied commercially by Novo Nordisk.

The injection monitoring module (1) comprises a hollow main body (11) which is dimensioned and sized to be coaxially mounted around the body (3) of the pen injection system (2). To this end, the hollow main body (11) comprises a central longitudinal bore (12) having a proximal extremity (13) and a distal extremity (14), and a central longitudinal axis that coincides with the central longitudinal axis (9). The hollow main body further comprises a distal body portion (15) which extends around and frictionally engages with, the outer surface (4) of the body (3) of the injection pen system (2) at a location on the pen body (3) distal to the dose setting wheel (6). Frictional engagement of the hollow main body (11) with the outer surface (4) of the pen body (3) can be achieved by providing an elastomeric frictional material (16) on an inner peripheral surface (17) of the hollow main body, such frictionally engaging materials being readily known in the art per se, to provide a push-fit or sliding-fit engagement of the distal portion (15) with the outer surface (4) of the pen body (3). The hollow main body extends in a proximal direction, above and beyond the limit of the activator button (10) of the pen injection system (2), such that the bore (12) houses both the dose setting wheel (6) and the activator button (10), and the dose setting wheel is free to rotate in the bore (12). The proximal extremity (13) of the bore corresponds so the proximal extremity of the hollow main body (11).

The hollow main body (11) further comprises a magnetic field production means (18, 19) located on or within the hollow main body (11), at the proximal extremity (13) of the central longitudinal bore (12). The magnetic field production means (18, 19) are suitably provided by a pair of single dipole magnets (18, 19), located diametrically opposite one to the other, each magnet respectively having a north (N) pole (18a, 19a) and a south (S) pole (18b, 19b), with each pair of poles being preferably oriented in axial alignment from N-S along the central longitudinal axis, with the north pole being located proximally, and the south pole distally, see for example FIG. 5. The dipole magnets (18,a, 18b, 19a, 19b) can be suitably formed into the shape of a rod, or alternatively as a disk or ring, or any other suitable shape. The magnets are located in suitably dimensioned recesses (20, 21) provided in the hollow main body (11), the recesses (20, 21) being located at the proximal extremity (13) of the body (11). Alternatively, the magnetic field production means can be a single dipole ring shaped magnet, which is seated on a peripheral proximal surface or within a corresponding annular recess of the hollow main body (11) at the proximal extremity (13) of said hollow main body. It will be understood from the above that the magnetic field production means do not rotate freely about the central longitudinal axis because the hollow main body (11) is mounted on the pen body (3) around said central longitudinal axis (9) in a fixed positional relationship with the hollow main body (11), which is frictionally held in position at the distal portion onto the outer surface (4) of the pen body (3) via the frictional engagement means (16).

The hollow main body (11) further comprises an inner sleeve (22) located within the central longitudinal bore (12), and configured to frictionally engage with an outer surface of the dose setting wheel (6) to co-rotate around the central longitudinal axis (9), without axial translation along said central longitudinal axis, but with the dose setting wheel (6) during during dose setting. The inner sleeve (22) will be described in more detail below, with regard in particular to FIGS. 5, 6A and 6B.

The injection monitoring module is illustrated in a schematic perspective representation in FIG. 3. In this view, the hollow main body (11), distal portion (15) and respective proximal (13) and distal (14) extremities are indicated. FIG. 3 also shows that the main hollow body (11) is shaped with a gradually widening diameter from the proximal extremity towards a point (23) adjacent, or in proximity, to the distal extremity (14) of the distal portion (15). This widening diameter corresponds to a widening of the bore (12) enabling the hollow main body to be inserted onto and around the proximal extremity of the pen and fit over the dose setting wheel (6) of the pen, whilst leaving sufficient room within the bore to receive the inner sleeve (22) so that the latter may engage with an outer surface of the dose setting wheel. The distal portion (15) comprises a correspondingly shaped narrowing diameter extending from the point (23) at which the hollow main body (11) is at its widest diameter, towards the distal extremity (14). The point (23) of widest diameter is also the point at which the hollow main body (11) and distal portion (15) are suitably configured to prevent translational movement of the inner sleeve (22) along the central longitudinal axis, as will be described in more detail hereinafter with reference to FIGS. 5 6A and 6B.

FIG. 4 is a schematic representation of the injection monitoring module according to the invention, when viewed from the distal extremity (14) of the distal portion (15) of the hollow main body (11) along the bore (12) and central longitudinal axis (9), the latter being represented by the intersection of cross-hairs A′-A″ and B′-B″. In this view, the inner peripheral surface (17) of the distal portion (15) of the hollow main body is indicated, as is the inner sleeve (22). Further represented are contact, or engagement, surfaces (24) provided respectively at a proximal extremity of the inner sleeve (22), and corresponding contact, or engagement surfaces (25) provided on an injection monitoring system housing (26) and extending in a distal direction therefrom into the bore (12), the engagement surfaces (24) and corresponding engagement surfaces (25) cooperating with each other as described in more detail hereafter.

FIG. 5 presents a schematic exploded perspective view of the components of an exemplary injection monitoring module according to the invention. The hollow main body (11) and distal portion (15) are shown in this representation as separate components which can be assembled together when the distal portion (15) and hollow main body are mounted on the body (3) of pen injection system (2). Whilst not obligatory, such a dual component presentation is particularly advantageous in that it further facilitates insertion of the inner sleeve (22) into the bore (12), and its location against the outer surface of the body (3) of the pen injection system (2), as well as facilitating its relative positioning with regard to the distal portion (15) and hollow main body, blocking the inner sleeve from translating in a proximal or distal direction once the monitoring module is mounted on the body (3) pen injection system. To that end, the point (23) of widest diameter of both the hollow body (11) and the distal portion (15) is suitably the point at which these components are mated together on mounting of the injection monitoring module, for example, by providing a distal annular skirt (27) and proximally projecting distal annular wall (28) having a reduced diameter compared to the skirt (27), on the hollow main body (11) at a distal extremity (29) thereof, and a corresponding distally projecting annular wall (30) at a proximal extremity (31) of the distal portion, which engages with the distally projecting annular wall (28) and corresponding distal annular skirt (27). The hollow main body (11) and distal portion (15) can be suitably clipped, adhered, and/or bonded to each other at the widest point (23), for example using ultrasound welding, or any other appropriate form of bonding technique, or other engagement means enabling the hollow main body (11) and distal portion (15) to be maintained rigidly together. Alternatively, both hollow main body (11) and distal portion (15) can be provided as a single unit, appropriately dimensioned and configured to fit around and engage with, a corresponding injection pen body (3).

The inner sleeve (22) further comprises at least one, or a plurality, of elastically deformable surfaces (32) extending inwardly towards the central longitudinal axis (9) from said inner sleeve (22), forming at least one, or a plurality, of frictionally engaging surfaces (32) to frictionally engage with an outer surface of the dose setting wheel. The at least one, or plurality, of elastically deformable surfaces (32) extending inwardly towards the central longitudinal axis from the inner sleeve (22) can appropriately be provided as a ring (33) of elastically deformable material comprising a plurality of coaxially aligned, radially spaced apart teeth, extending in a same direction from said ring (33), and said ring is usefully seated at a proximal extremity (34) of the inner sleeve (22), with the teeth oriented to extend in a distal direction, along an outer and/or inner surface of said sleeve (22). Advantageously, the elastically deformable material is a suitable elastomer, such as a SEBS elastomer, generally known per se in the art. The elastically deformable surfaces (32) or teeth extend through a plurality of corresponding coaxially aligned, radially spaced apart, openings (35) traversing the inner sleeve (22) from an outer surface (36) to an inner surface (37) thereof. As will be readily understood from the above, the elastically deformable surfaces advantageously extend from one side, for example, form the outer surface (36), of the inner sleeve (22), through the body material of the inner sleeve (22), and through to the other side, for example, the inner surface (37) of the inner sleeve, thereby providing one or more frictionally engaging contact surfaces which come into contact with an outer surface of the dose setting wheel (6) of the pen injection system, ensuring that any rotation of the inner sleeve is transmitted to the dose setting wheel, and vice-versa.

As has been mentioned above, and as illustrated in greater detail in FIGS. 6A and 6B, which are representative cross-sectional views of the injection monitoring device according to the invention, the inner sleeve (22) is blocked against translational movement in a proximal or distal direction along the central longitudinal axis (9). FIGS. 6A and 6B represent the injection monitoring module in the first, or dose setting position, that is, the position in which the monitoring module would be found after mounting on the pen injection body. The difference between FIG. 6A and FIG. 6B is merely one of the rotation of the cross-section about the central longitudinal axis (9). The hollow main body (11) thus further comprises translational abutment means (38) adapted and configured to prevent axial translational movement of the inner sleeve (22) along the central longitudinal axis, when the injection monitoring module (1) is in the mounted position on the injection pen system (2). The translational abutment means (38) are shaped and dimensioned to prevent axial translational movement of the inner sleeve, beyond a predetermined point (23) in, or on, the hollow main body, along the central longitudinal axis (9) in at least a distal direction, but also advantageously and preferably in a proximal direction along said central longitudinal axis (9). To that end, the translational abutment means of the hollow main body (11) are formed as an annular groove (38) or annular slot provided on an inside surface (17) of the hollow main body (11). The annular groove (38) can be suitably formed by the cooperating surfaces formed from a distally oriented surface (39) provided on the hollow main body (11), and a respectively correspondingly proximally oriented surface (40) of the distal body portion (15).

Additionally, the inner sleeve further comprises surface engagement means (41) located adjacent to, or substantially at, a distal extremity of said inner sleeve, wherein said surface engagement means are configured to engage with at least an inner surface of the distal body portion (15) and the hollow main body (11), for example, the annular groove (38) formed by distally oriented surface (39) and proximally oriented surface (40), and thereby prevent translational movement of the inner sleeve in a distal and/or proximal direction, when the injection monitoring module (1) is in the mounted position on the injection pen system (2). To that end, the surface engagement means (41) can appropriately be formed by at least one continuous projection (41), or a plurality of separate projections (41a, 41b, 41c, etc), extending radially outwardly from the outer surface (36) of said inner sleeve (22). Said projections (41) comprise at least one distally oriented surface (42), which distally oriented surface (42) engages with a respectively proximally oriented surface (40) of the annular groove (38) provided on the inside surface (17) of the hollow main body (11). The interaction between the cooperating surfaces of the projections (41) with the annular groove (38) and respective surfaces (39, 40) prevents any substantial translational movement of the inner sleeve along the central longitudinal axis when the injection monitoring module is mounted on the pen injection system, but said groove (38) and projections (41) are nonetheless appropriately and correspondingly dimensioned to permit rotation of the inner sleeve (22) about the central longitudinal axis (9), the projections (41) being free to move around said axis (9) within the groove (38) when a rotational force or effort is applied to the inner sleeve (22), for example, during dose setting.

As is visible from the figures, in particular, FIGS. 5, 6A and 6B, the inner sleeve is furthermore connected to an injection monitoring system (43), indicated in square brackets and comprising several components, among which an injection monitoring system housing (26). The injection monitoring system housing (26) is shaped and configured to resemble a cup with a stem, with a base wall (44) extending over substantially the same, or similar diameter as the hollow main body (11), and substantially perpendicular to the central longitudinal axis, and a first annular wall (45) extending from an outer periphery of the base wall (44), in a proximal direction away from said base wall (44), thereby forming a cup shaped part with an inner volume that is closed by a proximal cap (46) forming a push button, which is snap or push-fitted or adhered, or otherwise affixed onto said proximally extending first annular wall (45) at the proximal extremity (47) of said first annular wall. The base wall (44) further comprises a second annular wall (48) extending from the base wall (44) in a distal direction from a location radially spaced apart from the central longitudinal axis (9), and having a diameter smaller than the diameter of the bore (12) of the hollow main body. The second annular wall (48) is closed at its distal extremity (49) by a cross wall (50) to form the stem of the cup. The stem of the cup sits within the bore (12) of the hollow main body. The injection monitoring system housing (26), as defined by the cup shaped inner volume, receives and seats an electronic component board (51). The internal volume of the stem formed by the second annular wall (48) and the cross wall (50) receives an autonomous power supply (52), such as a single use, or rechargeable, battery, for example, a lithium ion battery electrically connected to the electronic component board (51) to provide power thereto. The electronic component board (51) is appropriately and generally a printed circuit board of suitable dimensions to be located within the internal volume of the cup formed by the base wall (44) and proximally extending first annular wall (45). The injection monitoring housing (26) optionally further comprises a light guide window (54), integrated into or being part of, the first annular wall (45), for example, a translucent, opaque, or transparent material shaped and with crystalline properties selected to guide a lightwave from the inside volume of the cup, for example, as produced by an optionally present light emitting diode or other lightwave producing component, to the outside of the injection monitoring system housing (26).

The electronic component board (51) further comprises at least one magnetometer (53), advantageously located on the central longitudinal axis, and in the case of a substantially circular shaped component board, substantially in the centre thereof so that it is aligned on the central longitudinal axis. In addition to the magnetometer (53), the injection monitoring system (43) also comprises an integrated control and data processing unit (55) electrically connected to the magnetometer (53) for processing information received from the magnetometer. The integrated control and data processing unit (55) handles all electrical communication and signalling between the different electronic components of the injection monitoring system. It is also responsible for execution of the dose management system and calculations enabling the precise positional location of the magnet to be calculated and determined, as well as handling signals from the autonomous power supply (52). The electronic component board can further be connected to a USB port (56), which can be configured as a power supply recharging port for a rechargeable battery (52), and/or be configured to enable basic setup of any programmable memory on the electronic component board, or to configure the data processing unit (55). The integrated control and data processing unit (55) usually also comprises communication means which communicate with a local or remote data processing system, e.g. on a smartphone, such as a wireless communications circuit, for example, a Bluetooth® or BluetoothLE® wireless communications system, to name but two of many types of suitable communications means. The integrated control and data processing unit (55) can suitably be programmed remotely, upon first use, or receive information and updates, in a similar way to other electronic devices today containing integrated control and data processing units, for example, wirelessly, or via any other suitable link, such as the USB port (56). Such integrated control and data processing units are known per se, and often integrate a central processing unit, a real time clock, one or more memory storage systems, and optionally communications systems or subsystems, along with other desired components. The electronic component board (