Drug delivery devices and dosage measurement systems

Abstract

The present disclosure relates to a medication delivery device including a rotation sensor suitable for being part of or a part of a medication injection device to measure the amount of a dose dispensed by the medication injection device.

Description

[Technical field]

[0001] The present disclosure relates to drug delivery devices and dosage measuring systems for drug delivery devices. [Background technology]

[0002] There are various diseases that require periodic treatment by drug delivery using a drug delivery device. Such delivery can be performed by using an injection device used either by a medical professional or by the patient himself. As an example, type 1 and type 2 diabetes can be treated by the patient himself by injection of an insulin dose, for example, once or multiple times a day. For example, a pre-filled disposable insulin pen can be used as the injection device. Alternatively, a reusable pen may be used. A reusable pen allows for replacing the empty drug cartridge with a new cartridge. Any pen may come with a set of one-way needles that are replaced before each use. The insulin dose to be injected can then be manually selected, for example, by turning the dose knob on the insulin pen and observing the actual dose from the dose window or display of the insulin pen. The dose is then injected by inserting the needle into the appropriate skin area and pressing the injection button of the insulin pen. It is desirable to measure information about the status and / or use of the injection device, for example, information about the insulin dose already injected, so that the insulin injection can be monitored, for example, to prevent mishandling of the insulin pen and to keep track of the dose already taken. Summary of the Invention [Problem to be solved by the invention]

[0003] An object of the present disclosure relates to improved drug delivery devices and dosage measurement systems for drug delivery devices. [Means for solving the problem]

[0004] According to the present disclosure there is provided a drug delivery device comprising a reservoir for a drug, a dispensing mechanism operable to dispense the drug from the reservoir, the dispensing mechanism including a sleeve configured to rotate during dispensing of the drug, the dispensing mechanism having a plurality of features at an end of the sleeve, and a dose measuring system including at least one mechanically actuated sensor configured such that, in use, rotation of the sleeve causes the successive features to engage the sensor, thereby causing the sensor to detect rotation of the sleeve, and a processor configured to determine a dose dispensed from the drug reservoir based on the detected rotation of the sleeve.

[0005] The use of a mechanical sensor that engages the sleeve provides a compact system for determining the dose dispensed from the drug reservoir. Mechanical sensors are generally more energy efficient than other types of sensors, such as optical gates, and therefore may use smaller batteries. Because the mechanical sensor engages features on the sleeve of the dispensing mechanism, the system may be more portable than if the sensor detected an external component of the device.

[0006] In some embodiments, the plurality of features comprises a plurality of teeth.

[0007] In some embodiments, the feature is formed on a proximal end of the sleeve.

[0008] A feature at the proximal end of the sleeve allows the sensor to be axially aligned with the sleeve. The sensor may be located proximally of the sleeve.

[0009] In some embodiments, the sleeve is a dial sleeve or a drive sleeve.

[0010] In some embodiments, the sensor includes a sensing member configured to move from an unactivated state to an activated state when engaged by one of the features during rotation of the sleeve, where the sensor detects movement of the sensing member between the unactivated state and the activated state.

[0011] In some embodiments, each feature includes a leading edge, and during a rotation of the sleeve, engagement of the sensor with the leading edge of a first one of the features to engagement of the sensor with the leading edge of an adjacent second one of the features represents one coding cycle, with the sensor being activated for 40-60% of the coding cycle, and preferably for about 50% of the coding cycle. Such an arrangement provides a symmetrical scheme, which may aid in tolerance robustness since tolerances are distributed symmetrically in many situations.

[0012] In some embodiments, the medication delivery device further includes a dose dial and a housing, where the dose dial is configured to rotate relative to the housing to set a dose of medication delivered by the dispensing mechanism, and where the sensor is attached to the dose dial.

[0013] The sensor is mounted on the dose dial, allowing for a compact drug delivery device. In some embodiments, the sensor is mounted inside the dose dial, making the dose measurement system unobtrusive and compact.

[0014] In some embodiments, the drug delivery device includes a torque limiter, wherein the sensor is attached to the dose dial via the torque limiter, whereby rotation of the dose dial relative to the housing with a torque greater than a predetermined limit moves the torque limiter to an open state, thereby allowing the dose dial to rotate relative to the sensor, preferably the torque limiter includes an overload clutch.

[0015] The torque limiter prevents damage to the sensor if the user applies a large torque to the dose dial while setting the dose to be delivered by the measurement delivery device.

[0016] In some embodiments, the drug delivery device further includes a one-way mechanism, where the sensor is attached to the dose dial via the one-way mechanism, whereby the sensor is prevented from rotating relative to the dose dial in the direction that the sleeve rotates during drug dispensing, and is permitted to rotate relative to the dose dial in the opposite direction that the sleeve rotates during drug dispensing.

[0017] If a user urges the sleeve to rotate in a direction opposite to the direction the sleeve is intended to rotate during medication dispensing, the one-way mechanism prevents damage to the sensor, because the sensor will rotate with the sleeve in that opposite direction.

[0018] According to another aspect, there is provided a dose measuring system for a medication delivery device, the medication delivery device comprising: a housing including a reservoir for the medication; a dispensing mechanism operable to dispense the medication from the reservoir, the dispensing mechanism including a component configured to rotate during dispensing of the medication and including a plurality of features; and an actuator configured to be movable relative to the housing when actuated to operate the dispensing mechanism to dispense the medication from the reservoir, the dose measuring system comprising: a sensor movable from an idle position to a detection position, where rotation of the component causes successive features to be detected by the sensor, thereby causing the sensor to detect rotation of the component; a processor configured to determine a dose dispensed from the medication reservoir based on the detected rotation of the component; and an activation switch movable from an initial off state to an on state when the actuator is actuated to activate the dose measuring system, the sensor configured to be attached to the actuator, whereby actuation of the actuator moves the sensor relative to the housing to reach the detection position, where the activation switch reaches an on state before the sensor reaches the detection position.

[0019] The sensor and activation switch configuration ensures that the dose-measuring system is activated before the sensor reaches the detection position, which helps to ensure that the sensor does not reach the detection position until the dose-measuring system is powered on.

[0020] In some embodiments, the actuator is slidable relative to the housing. A sliding movement of the actuator may be easier for the patient, especially if the patient is elderly or infirm.

[0021] In some embodiments, the activation switch includes a pivot member that pivots from an off state to an on state to activate the dose measurement system.

[0022] In some embodiments, the medication delivery device includes a stop, and the activation switch is configured to abut the stop when the activation switch is in an off state.

[0023] In some embodiments, when the actuator is moved to operate the dispensing mechanism, thereby biasing the activation switch to an on state, the activation switch is configured to engage a portion of the drug delivery device, preferably the portion including a portion of the dispensing mechanism.

[0024] This configuration allows for actuation of the activation switch without the need for additional components, hi some embodiments, the portion includes a drive sleeve of the dispensing mechanism.

[0025] In some embodiments, the activation switch is configured to move a first distance from an off state to an on state and the sensor is configured to move a second distance from an idle position to a detection position, where the second distance is greater than the first distance. This helps ensure that the activation switch reaches the on position before the sensor reaches the detection position.

[0026] In some embodiments, the dosage measuring system includes first and second radial bearings, where the actuator is rotatably mounted via the first and second bearings to a portion of the device, the first and second bearings being axially spaced apart. The portion of the device may be, for example, a rotatable sleeve of the device, such as a dial sleeve, or may be a housing.

[0027] In some embodiments, the dose measuring system comprises a support member and a connecting member, wherein the dose setting dial is fixed relative to the support member, and wherein the support member is connected to the connecting member, preferably the support member is connected to the connecting member via a pivot.

[0028] In some embodiments, the support member is connected to the connecting member via at least one radial bearing, preferably via a first and a second radial bearing, optionally the second radial bearing being axially spaced from the first radial bearing in the direction of actuation movement of the actuator.

[0029] In some embodiments, the dose measuring system has any of the configurations discussed above. In some embodiments, there is provided a drug delivery device including a dose measuring system having any of the configurations discussed above.

[0030] According to another aspect, there is provided a dosage measuring system for a drug delivery device comprising a reservoir for the drug and a dispensing mechanism operable to dispense the drug from the reservoir, the dispensing mechanism comprising a component configured to rotate during dispensing of the drug and including a plurality of first and second encoder areas, the dosage measuring system comprising first and second sensors configured to distinguish between the first and second encoder areas and to detect rotation of the component such that, in use, rotation of the component causes one of the first encoder areas to be aligned with the first sensor while one of the second encoder areas is aligned with the second sensor and then one of the second encoder areas is aligned with the first sensor while one of the first encoder areas is offset with the second sensor, and a processor configured to determine a dose dispensed from the drug reservoir based on the detected rotation of the component.

[0031] By providing offset first and second sensors, the resolution for measuring component rotation for a given size encoded area can be improved, resulting in a more accurate determination of the dose dispensed from the drug reservoir.

[0032] In some embodiments, the component includes a plurality of features, where each first encoding region includes at least a portion of a respective feature detectable by the first and second sensors when the component rotates, and where the second encoding regions are disposed between adjacent first encoding regions.

[0033] In some embodiments, each feature includes teeth, where each first encoder region includes at least a portion of a respective tooth detectable by the first and second sensors as the component rotates, and where each second encoder region includes at least one gap between adjacent teeth.

[0034] In some embodiments, the first and second sensors are positioned such that for all rotational positions of the component in which the first sensor is aligned with one of the first encoded regions, the second sensor is aligned with one of the second encoded regions.

[0035] This ensures that for a given number and size of encoded regions, the highest resolution for measuring component rotation can be achieved, and it is possible to ensure that the initial axial motion causes the first encoded region to be aligned with one of the first and second sensors, so that erroneous readings due to the initial axial motion can be ignored.

[0036] In some embodiments, the component includes multiple coding periods, where each coding period includes one of a first coding region and an adjacent second coding region, and where for a given rotational position of the component, the first sensor is aligned to a portion of one of the coding periods and the second sensor is aligned to a different portion of the one of the coding periods.

[0037] In some embodiments, the dosage measuring system further includes a third sensor, wherein the third sensor is aligned to a different portion of one of the coding periods for the first and second sensors when the component is in said given rotational position.

[0038] Thus, the processor can determine the rotational direction of the component.

[0039] In some embodiments, the dosage measuring system further includes a fourth sensor, and the fourth sensor is aligned with a different portion of one of the coding periods for the first, second, and third sensors when the component is in said given rotational position, so that the processor can determine the rotational orientation of the component.

[0040] In some embodiments, the dosage measuring system further includes a third sensor, the third sensor configured such that, when the components are rotated in use, the third sensor is aligned with one of the first encoded regions at the same time that the first sensor is aligned with one of the first encoded regions.

[0041] The third sensor provides redundancy in case the first sensor fails to detect the coded region due to a detection error and allows unlikely detection events to be filtered out. Thus, there is pair redundancy that allows erroneous switch state detections to be detected and compensated for.

[0042] In some embodiments, the dosage measuring system further includes a fourth sensor, the fourth sensor configured such that, when the components are rotated in use, the fourth sensor is aligned with one of the first encoded regions at the same time that the second sensor is aligned with one of the first encoded regions.

[0043] The fourth sensor provides redundancy in case the second sensor fails to detect the coded region due to a detection error, and allows unlikely detection events to be filtered out. Thus, there is pair redundancy that allows erroneous switch state detections to be detected and compensated for.

[0044] In some embodiments, when the first sensor is aligned at the transition between the first and second encoded regions, the third sensor is also aligned at the transition between the first and second encoded regions, and in some embodiments, when the second sensor is aligned at the transition between the first and second encoded regions, the fourth sensor is also aligned at the transition between the first and second encoded regions.

[0045] In some embodiments, each of the first and second encoded regions extends the same predetermined angle about the axis of rotation of the component.

[0046] In some embodiments, the predetermined angle is about 15 degrees or 30 degrees.

[0047] In some embodiments, the second sensor is offset from the first sensor in the first direction about the axis of rotation by an odd integer multiple of the angle subtended by each first encoded region about the axis of rotation.

[0048] In some embodiments, the second sensor is offset from the first sensor in the first direction by 165 degrees about the axis of rotation.

[0049] In some embodiments, each of the first and second encoded regions comprises a length extending in a rotational direction of the component, and wherein the dosage measuring system includes a third sensor that is offset from the first and second sensors such that, in use, when the first sensor is aligned with one of the first encoded regions and the second sensor is aligned with one of the second encoded regions, the third sensor is aligned at a different portion along the length of one of the first and second encoded regions.

[0050] In some embodiments, the processor is configured to determine the dose dispensed from the drug reservoir by a process that includes counting the number of transitions between the first and second coded regions detected by the first and second sensors.

[0051] In some embodiments, the first and second sensors are configured to move from an idle position to a detection position, where movement of the sensors to the detection position aligns one of the first and second regions with one of the first encoded regions, and where the processor is configured to compensate for said alignment upon movement of the sensors to the detection position when determining the administered dose.

[0052] This can improve accuracy in embodiments where the sensor moves axially to a detection position because, in some embodiments, such axial movement can cause one of the first and second sensors to align with the first coded region, which can appear as an erroneous reading of a transition to said first coded region, and the processor can ignore this erroneous reading to more accurately determine the administered dose.

[0053] In some embodiments, the processor is configured to determine a dose dispensed from the drug reservoir based on a signal from one of the first and second sensors and an inverse signal from the other of the first and second sensors.

[0054] In some embodiments, the processor is configured to determine a dose dispensed from the drug reservoir based on a superposition of a signal from one of the first and second sensors and an inverse signal from the other of the first and second sensors.

[0055] In some embodiments, the processor is configured to determine the dose dispensed from the drug reservoir by comparing the overlap to a first threshold and a second threshold higher than the first threshold, preferably by counting the number of times the overlap transitions from a value below the first threshold to a value above the second threshold and / or the number of times the overlap transitions from a value higher than the second threshold to a value below the first threshold.

[0056] This helps improve the accuracy of dose determination by helping to eliminate errors such as sensor noise and switch bounce. Additionally, having four sensors allows two simultaneous errors to be ignored, further improving accuracy.

[0057] In some embodiments, the dose measuring system has any of the configurations discussed above.

[0058] In some embodiments, a drug delivery system is provided that includes a dose measuring system.

[0059] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0060] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0061] [Figure 1] FIG. 2 is an exploded view of the drug delivery device. [Diagram 2]1 is a side cross-sectional view of a portion of a medication delivery device including a dose measuring system according to an embodiment. [Diagram 3] 3 is a side cross-sectional view of the medication delivery device of FIG. 2 prior to actuation of the actuator by a user; [Figure 4] 3 is a cross-sectional side view of the device of FIG. 2 with the actuator actuated by a user. [Diagram 5] FIG. 3 is a perspective view of the coding ring of the device of FIG. 2. [Figure 6] FIG. 3 is a perspective view of a dial sleeve of the device of FIG. 2. [Figure 7] FIG. 3 is a perspective view of a portion of the dial sleeve and a sensor of the device of FIG. 2. [Figure 8] FIG. 3 is a side view of a portion of the dial sleeve and sensor of the device of FIG. 2 with the sensing member in an unactivated state. [Figure 9] 3 is a side perspective view of a portion of the dial sleeve and sensor of the device of FIG. 2 with the sensing member in an activated state. FIG. [Figure 10] 3 is a schematic side view of the sensor of the device of FIG. 2 showing the sensing member being activated. [Figure 11] FIG. 3 is a schematic side view of the first and second coding areas of the dial sleeve of the device of FIG. 2. [Figure 12] FIG. 3 is a schematic side view of first and second encoded regions for activating a sensor of the device of FIG. 2. [Figure 13] 3 is a side cross-sectional view of a portion of the device of FIG. 2 showing a portion of the support member and connecting member. [Figure 14] 3 is a side cross-sectional view of a portion of the device of FIG. 2 showing a portion of a coupling member. [Figure 15] FIG. 3 is a schematic block diagram of a dose measuring system of the device of FIG. 2. [Figure 16] 16A-16C are schematic diagrams of a sensor of another embodiment of a dosage measuring system. [Figure 17] FIG. 16B shows a signal output from a sensor of the embodiment of FIG. 16A. [Figure 18]16B shows a signal output from a sensor of the embodiment of FIG. 16A and a superimposed signal. [Figure 19] FIG. 16C is a top view of the sensor and activation switch of the embodiment of FIG. 16B. [Figure 20] 16C shows signals output from the sensor and activation switch of the embodiment of FIG. 16B, and a superimposed signal. [Figure 21] FIG. 16D is a top view of the sensor and activation switch of the embodiment of FIG. 16C. [Figure 22] FIG. 13 is a perspective view of a portion of a dial sleeve and a sensor of another embodiment. [Diagram 23] FIG. 1 is a circuit diagram of an embodiment of a dosage measurement system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0062] In the following disclosure, embodiments are described with reference to an insulin injection device, however, the disclosure is not limited to such use and can also be implemented with drug delivery devices that release other drugs.

[0063] The term "distal" refers to a position relatively closer to the drug delivery site (eg, the injection site in the case of an injection device), and the term "proximal" refers to a position relatively farther from the drug delivery site.

[0064] 1 is an exploded view of a drug delivery device 1. In this example, the drug delivery device 1 is an injection device 1 such as a Sanofi AllStar® insulin injection pen or a Sanofi SoloStar® insulin injection pen, although as described below, the present disclosure can accommodate other types and makes of injection pens. The present disclosure can also accommodate other types of drug delivery devices, such as needleless injectors.

[0065] The injection device 1 of Figure 1 is a pre-filled injection pen and includes a housing 2 containing a reservoir 14 for the drug, in this embodiment an insulin container 14. A needle 15 is attachable to the reservoir 14. The injection device 1 may be disposable or reusable. The needle 15 is protected by an inner needle cap 16 and an outer needle cap 17 and / or an alternative cap 18.

[0066] The insulin dose released from the injection device 1 can be programmed by moving the dose setting member 12, which in this embodiment is a dose setting dial 12 that can be turned relative to the housing 2 to "dial in" the dose. The currently programmed dose is then displayed via the dosage window 13, for example in units. For example, if the injection device 1 is configured to administer, for example, human insulin, the dosage can be displayed in so-called international units (IU), where 1 IU is the biological equivalent of about 45.5 micrograms (1 / 22 mg) of pure crystalline insulin. Other units may also be used in drug delivery devices for delivering insulin analogues or other drugs.

[0067] The dose window 13 may be in the form of an aperture in the housing 2 that allows the user to view a limited portion of the number sleeve 10 that is configured to move when the dose setting dial 12 is turned to provide a visual indication of the currently programmed dose. It should be noted that the selected dose may be displayed in a manner different from that shown in the dose window 13 of FIG. 1. For example, only every other dose unit may be shown due to spatial constraints on the number sleeve 10. Dose units that are not shown numerically may be represented by graduations between the displayed numbers. Alternatively, the number sleeve 10 may remain stationary during the dose dialing phase, and as the dose is dialed in the dose window 13 moves to reveal the numbers corresponding to the dialed dose. In either case, the number sleeve 10 may be a component that rotates as the dose is being dispensed from the injection device 1.

[0068] In this example, the dose setting dial 12 includes one or more features 12a, 12b, 12c that facilitate programming by improving the grip a user gets when holding the dose setting dial 12. In another example (not shown), the dose setting dial does not include features.

[0069] The injection device 1 can be configured such that turning the dose setting dial 12 produces a mechanical click sound to provide auditory feedback to the user. The number sleeve 10 mechanically interacts with a piston in the insulin container 14. When the needle 15 is inserted into the patient's skin area and the dose setting dial 12 is then pressed axially relative to the housing 2, the insulin dose displayed in the display window 13 will be released from the injection device 1. The dose setting dial 12 thus forms an actuator that can be actuated by the user to dispense the medication. If the needle 15 of the injection device 1 remains in the skin area for a certain period of time after the dose setting dial 12 is pressed, a high percentage of the dose is actually injected into the patient's body. The release of the insulin dose may also produce a mechanical click sound, but this sound is different from the sound produced when rotating the dose setting dial 12 to set the dose to be delivered.

[0070] The injection device 1 includes a dial sleeve 10, which in this embodiment is the same component as the number sleeve 10. In other embodiments (not shown), the dial sleeve 10 can be fixed to the proximal end of the number sleeve 10.

[0071] The dial sleeve 10 has a proximal end near the dose setting dial 12. The dial sleeve 10 (and the number sleeve 10, which is the same component) rotates relative to the dose setting dial 12 during dose release, but does not rotate during dose dialing. During dose dialing, the user rotates the dose setting dial 12 relative to the housing 2, which causes a corresponding rotation of the dial sleeve 10 relative to the housing 2.

[0072] To operate the injection device 1 to dispense the medicament from the container 14, the dose setting dial 12 is configured to move axially a short distance relative to the housing 2 and dial sleeve 10 of the injection device 1. This movement occurs when a user applies force to an end of the dose setting dial 12, for example when the user presses the dose setting dial 12 axially towards an injection site. This movement disengages a clutch (not shown), allowing the dial sleeve 10 and other internal components of the injection device 1 to rotate relative to the dose setting dial 12. Alternatively, the injection device 1 may include a separate injection button (not shown in FIG. 1 ) attached to the dose setting dial 12, which moves axially relative to the housing 2 to cause the medicament to be dispensed. The injection button may be located at a proximal end of the dose setting dial 12.

[0073] In various embodiments, during delivery of an insulin dose, the dose setting dial 12 moves with an axial movement, i.e., without rotation, to its initial position, while the number sleeve 10 rotates back to its initial position, e.g., to display a dose of zero units.

[0074] The injection device 1 can be used for multiple injection processes until the insulin container 14 is empty or until the expiration date of the medication in the injection device 1 (eg, 28 days after first use).

[0075] Before the first use of the injection device 1, it may be necessary to perform a so-called "blank shot" to remove air from the insulin container 14 and the needle 15, for example by selecting 2 units of insulin and pressing the dose setting dial 12 while holding the injection device 1 with the needle 15 pointing up. For ease of explanation, it is assumed below that the discharged amount substantially corresponds to the injected dose, whereby for example the number of drug dose units discharged from the injection device 1 is equal to the number of drug dose units accepted by the user. Nevertheless, differences between the discharged amount and the injected dose (e.g. losses) may need to be taken into account in some applications of the device.

[0076] 2 to 15, there is shown an embodiment of a drug delivery device 100. The drug delivery device 100 is similar to the drug delivery device 1 described with respect to Fig. 1, and therefore a detailed description of the common features of the drug delivery device 100 will not be repeated hereafter. The difference is that the drug delivery device 100 includes a dose measuring system 101.

[0077] The drug delivery device 100 includes a housing 102 that contains a reservoir for the drug (not shown). The drug delivery device 100 further includes a dispensing mechanism 104 operable to dispense the drug from the reservoir.

[0078] The dispensing mechanism 104 includes a clutch 105, a dial sleeve 106, a drive sleeve 107, a drive member (not shown), a plunger rod (not shown), and a piston (not shown). The drive member may include a biasing member (not shown), such as a spring, configured to bias the drive sleeve 107 to rotate relative to the housing 102.

[0079] The drive sleeve 107 is coupled to the plunger rod such that rotation of the drive sleeve 107 in a first rotational direction (indicated by arrow "X" in Figures 7-11) moves the plunger rod distally along an axis to dispense medicament from the reservoir. More specifically, a piston (not shown) is attached to the distal end of the plunger rod such that distal axial movement of the plunger rod while the drive sleeve 107 is rotated in the first rotational direction X slides the piston distally within the reservoir to dispense medicament therefrom.

[0080] In one embodiment, the drive sleeve 107 and plunger rod include corresponding threads (not shown) that engage such that rotation of the drive sleeve 107 causes axial movement of the plunger rod. In another embodiment (not shown), the drive sleeve 107 is coupled to the plunger rod through one or more intermediate components (not shown).

[0081] Clutch 105 is initially in an engaged position in which it prevents rotation of drive sleeve 107 under the force of the drive member in the first rotational direction X. In some embodiments, clutch 105 has one or more splines (not shown) or other engaging elements that engage drive sleeve 107 or another component when clutch 105 is in the engaged position to prevent rotation of drive sleeve 107 relative to housing 102.

[0082] The drug delivery device 100 further includes a dose setting member 108, which in this embodiment is a dose setting dial 108 attached to the proximal end of the housing 102. The drug dose to be expelled from the drug delivery device 100 can be programmed or "dialed" by turning the dose setting dial 108, and the currently programmed dose is then displayed, e.g. in units, via a dosage window (not shown). In some embodiments, the dose setting dial 108 is rotated relative to the housing 102 in a second rotational direction opposite the first rotational direction X, whereby the dial sleeve 106 is also rotated in the second rotational direction relative to the housing 102 from an initial position (representing a dose "zero") until the desired dose is selected.

[0083] The dial sleeve 106 has a proximal end near the dose setting dial 108. The dial sleeve 106 (and the number sleeve 106, which is the same component) rotates relative to the dose setting dial 108 during dose emission, but does not rotate during dose dial setting. In other embodiments (e.g., in embodiments where the dose setting dial 108 includes a separate actuator, such as a push button, the dial sleeve 106 does not rotate relative to the dose setting dial 108 during dose emission, but instead the dose setting dial 108 rotates with the dose sleeve 106, and sometimes both the dose setting dial 108 and the dial sleeve 106 rotate relative to the actuator).

[0084] During dose dialing, a user rotates the dose setting dial 108 in a second rotational direction relative to the housing 102 , which causes a corresponding rotation of the dial sleeve 106 relative to the housing 102 .

[0085] The dispensing mechanism 104 further includes a number sleeve 106, which in this embodiment is the same component as the dial sleeve 106. In other embodiments (not shown), the dial sleeve can be fixed to the number sleeve.

[0086] A user can determine that the desired dose has been selected by viewing number sleeve 106 through a viewing window (not shown) in housing 102 .

[0087] The dose setting dial 108 forms an actuator that can be actuated by a user to dispense the medication. More specifically, the dose setting dial 108 is axially slidable relative to the housing 102 to operate the dispensing mechanism 104 to dispense the medication from the reservoir. In some embodiments, rotation of the dose setting dial 108 in a second rotational direction during dose dialing causes the dose setting dial to move proximally along the axis. In other embodiments, rotation of the dose setting dial 108 in a second rotational direction during dose dialing does not cause the dose setting dial 108 to move along the axis.

[0088] In operation, the dose setting dial 108 is configured to move axially relative to the housing 102 a short distance. This movement occurs when a user applies force to the dose setting dial 108, for example when the user pushes the dose setting dial 108 distally along the axis toward an injection site. This axial movement of the dose setting dial 108 disengages the clutch 105, which moves the clutch 105 to a disengaged position. For example, this distal movement of the dose setting dial 108 causes a corresponding distal movement of the clutch 105, which disengages the clutch 105, for example disengaging a spline or other engagement element (not shown). By disengaging the clutch 105, the dial sleeve 106 and the drive sleeve 107 can rotate relative to the housing 102 and the dose setting dial 108 in a first rotational direction X under the force of the drive member to dispense medicament from the reservoir.

[0089] As long as the dose setting dial 108 continues to be pressed by the user, the clutch 105 is maintained in the disengaged position, and thus the dial sleeve 106 and the drive sleeve 107 continue to rotate in the first rotation direction X under the force of the drive member to deliver medication to the user until the dial sleeve 106 reaches an initial position. The dose setting dial 108 can be biased in the proximal direction by a dial biasing member (not shown).

[0090] The dial sleeve 106 includes a cylindrical body 110 and an encoder ring 111 disposed at a proximal end of the body 110. In this embodiment, the encoder ring 111 is attached to the body 110, but in other embodiments, the encoder ring 111 can be integrally formed with the body 110 (e.g., the encoder ring 111 and the body 110 are molded or cast from a single piece of material).

[0091] Coding ring 111 includes a plurality of features 112, which in this embodiment are teeth 112 having gaps 113 therebetween. Teeth 112 extend in a proximal direction.

[0092] The dosage measuring system 101 further includes a mechanically actuated sensor 114 configured such that, in use, rotation of the dial sleeve 106 in a first rotational direction X causes the continuous feature 112 to engage the sensor 114, thereby causing the sensor 114 to detect rotation of the dial sleeve 106.

[0093] The dose measurement system 101 further includes one or more processors 115 configured to determine the dose dispensed from the medication reservoir based on the detected rotation of the dial sleeve 106. The processor 115 may include, for example, a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or the like.

[0094] The dosage measurement system 101 further includes one or more computer readable memory media. In this embodiment, the computer readable memory media includes memory units 116A, 116B including a program memory 116A and a main memory 116B, which can store software for execution by the processor 115.

[0095] The dosage measuring system 101 further comprises a battery 109 configured to power the dosage measuring system 101 .

[0096] The dosage measurement system 100 further includes an output 117. The output 117 may be a wireless communication interface for communicating with another device over a wireless network such as Wi-Fi or Bluetooth®, or may be an interface for a wired communication link, such as a socket for receiving a Universal Serial Bus (USB), mini-USB, or micro-USB connector.

[0097] In this embodiment, the sensor 114 is a mechanically actuated switch 114. In one particular embodiment, the sensor 114 is a C&K™ HDT0001 switch.

[0098] In some embodiments, when the feature 112 engages the switch 114 during rotation of the dial sleeve 106, the switch 114 is moved from one of an on or off state to the other of an on or off state.

[0099] The sensor 114 includes a sensing member 118 configured to move from an inactivated state to an activated state when the sensing member 118 engages one of the features 112 during rotation of the dial sleeve 106. The sensor 114 is configured to detect movement of the sensing member 118 between the inactivated state and the activated state. The sensing member 118 may be a pivot member 118 that rotates when one of the features 112 engages the sensing member 118 during rotation of the dial sleeve 106.

[0100] In some embodiments, each feature 112 includes a leading edge 112A that is positioned such that as the dial sleeve 106 rotates in the first rotational direction X, the leading edge 112A of each feature 112 abuts the sensor 114 in sequence. In some embodiments, during rotation of the dial sleeve 106, engagement of the sensor 114 with the leading edge 112A of a first one of the features 112 to the leading edge 112A of an adjacent second one of the features 112 represents one coding period.

[0101] In some embodiments, the sensor 114 is activated for 40% to 60% of the coding period. Preferably, the sensor 114 is activated for about 50% of the coding period. When the dial sleeve 106 is rotated in the first rotation direction X during medication administration, the sensor 114 is activated for 50% of the angular positions of the dial sleeve 106 in one complete rotation, and the sensor 114 is not activated for the remaining 50% of the angular positions of the dial sleeve 106.

[0102] In some embodiments, the drug delivery device 100 includes a torque limiter (not shown). The sensor 114 is attached to the dose setting dial 108 via the torque limiter, such that rotation of the dose dial 108 relative to the housing 102 with a torque greater than a predetermined limit moves the torque limiter to an open state, thereby rotating the dose setting dial 108 relative to the sensor 114. Optionally, the torque limiter includes an overload clutch (not shown).

[0103] As explained above, in some embodiments, pushing the dose setting dial 108 axially relative to the housing 102 disengages the clutch 105, allowing the dial sleeve 106 and the drive sleeve 107 to rotate relative to the housing 102 and the dose setting dial 108. In some embodiments, with the dose setting dial 108 depressed and the clutch 105 disengaged, a user can grasp the dial sleeve 106 and rotate it in a second rotational direction relative to the dose setting dial 108 against the force of the drive mechanism. This unintended operation of the device 100 may cause damage to the device 100. In particular, the sensing member 118 of the sensor 114 may be shaped and positioned to detect rotation of the dial sleeve 106 in a first rotational direction relative to the dose setting dial 108, i.e., to allow the sensing member 118 to move over the feature 112 without getting stuck. Instead, if the dial sleeve 106 is forced in the second rotational direction relative to the dose setting dial 108, this may cause the shaped portion 112 of the dial sleeve 106 to catch on the sensing member 118 of the sensor 114, which may result in damage to the sensing member 118 or misalignment of the sensing member 118 relative to the shaped portion 112.

[0104] In some embodiments, the drug delivery device 100 includes a one-way mechanism (not shown). The one-way mechanism can be configured to alleviate the above-mentioned conditions.

[0105] In one embodiment, the sensor 114 is attached to the dose setting dial 108 via a one-way mechanism, whereby rotation of the sensor 114 relative to the dose setting dial 108 is resisted by the one-way mechanism. Thus, under normal operating conditions, when the clutch 105 is disengaged and the dial sleeve 106 rotates in the first rotational direction X during medication dispensing, the formation 112 moves over the sensing member 114 which is held stationary by the one-way mechanism, such that relative rotation between the formation 112 and the sensing member 114 is detectable.

[0106] The one-way mechanism is configured to allow rotation of the sensor 114 in a second rotational direction relative to the dose setting dial 108. Thus, in the unintended operating situation discussed above where the user disengages the clutch 105 and then urges the dial sleeve 106 in the second rotational direction, the feature 112 is biased against the sensing member 118, urging the sensor 114 to rotate in the second rotational direction as well. The one-way mechanism allows rotation of the sensor 114 in the second rotational direction, such that the sensor 114 rotates with the dial sleeve 106 in the second rotational direction relative to the dose setting dial 108, such that the feature 112 is not biased over the sensing member 118, thus preventing damage to the sensing member 118 and / or the feature 112. In some embodiments, the one-way mechanism may include ratchet teeth on one or both of the dose setting dial 108 and the sensor 114.

[0107] The sensor 114 is attached to the dose setting dial 108 such that axial movement of the dose setting dial 108 relative to the housing 102 to operate the dispensing mechanism 104 to dispense medication also moves the sensor 114 axially. More specifically, the sensor 114 moves from an idle position (shown in FIG. 3 ) (where the sensor 114 is spaced apart from the features 112 in the axial direction of the medication delivery device 100) to a detection position (shown in FIG. 4 ) (where the successive features 112 are detected by the sensor 114 as the sensor 114 moves distally, thereby rotating the dial sleeve 106), whereby the sensor 114 detects the rotation of the dial sleeve 106. In this embodiment in which the sensor 114 includes a mechanical switch 114, when the sensor 114 is in the detection position, the features 112 physically engage the sensor 114 as the dial sleeve 106 rotates in the first rotational direction X.

[0108] The medication delivery device 100 further includes an activation switch 119 that is movable from an initial off state (as shown in FIG. 3 ) to an on state when the dose setting dial 108 is actuated to activate the dose measuring system 101. For example, movement of the activation switch 119 to the on state may wake up or power on one or more of the sensor 114, the processor 115, or other components of the dose measuring system 101.

[0109] In this embodiment, the activation switch 119 is attached to the dose setting dial 108 so as to move with the dose setting dial 108, whereby the activation switch 119 is biased against a component of the drug delivery device 100, such as the drive sleeve 107, to move the activation switch 119 to an on state.

[0110] In another embodiment (not shown), the activation switch 119 is attached to a component of the medication device 100 other than the dose setting dial 108, where sliding movement of the dose setting dial 108 during actuation urges the dose setting dial 108 or a portion connected to the dose setting dial 108 against the activation switch 119, moving the activation switch 119 to an on state. For example, the activation switch 119 may be attached to the proximal end of the drive sleeve 107.

[0111] The sensor 114 and activation switch 119 are configured such that when the dose setting dial 108 is actuated by the user sliding the dose setting dial 108 distally, the activation switch 119 reaches an on state before the sensor 114 reaches a detection position. This helps to ensure that the dose measuring system 101 has time to power on before the sensor 114 reaches a detection position for detecting rotation of the dial sleeve 106. This improves the accuracy of measuring the dose dispensed by the dispensing mechanism 104.

[0112] Those skilled in the art will recognize that many different types of activation switch 119 may be used, such as a repeater, an analog switch, a pressure sensor, a push switch, or a flick switch. In one embodiment, activation switch 119 includes a Panasonic™ ESE13 switch.

[0113] In this embodiment, the activation switch 119 includes a pivot member 120 that pivots from an off state to an on state to activate the dose measuring system 101. The pivot member 120 is pivotally connected to the dose setting dial .

[0114] The activation switch 119 is configured to engage a portion of the drug delivery device 100 when the dose setting dial 108 is moved axially to operate the dispensing mechanism 104, thereby biasing the activation switch 119 to an on state. In some embodiments, the portion includes a portion of the dispensing mechanism 104, such as the drive sleeve 107. In some embodiments in which the activation switch 119 includes a pivot member 120, the pivot member 120 engages said portion of the drug delivery device 100 when the dose setting dial 108 is moved axially, thereby rotating the pivot member 120 from an off state to an on state relative to the dose setting dial 108.

[0115] In some embodiments, the drug delivery device 100 includes a stop 122, and the activation switch 119 is configured to abut the stop 122 when the activation switch 119 is in an off state.

[0116] In some embodiments, the drug delivery device 100 includes a support member 121. The support member 121 projects axially and distally from the dose setting dial 108. The support member 121 is generally cylindrical and configured to be received within a bore of the drive sleeve 107. The support member 121 moves into the drive sleeve 107 when the dose setting dial 108 is actuated. The support member 121 may be attached to or integrally formed with the dose setting dial 108. In one embodiment, the support member 121 is attached to the activation switch 119.

[0117] Optionally, the support member 121 includes a stop 122 against which the activation switch 119 abuts when the activation switch 119 is in the off state. The stop 122 may be in the form of a stop surface 122 on the support member 121. In this embodiment, the pivot member 120 abuts against the stop surface 122 when the activation switch is in the off state. When the pivot member 120 is urged against the drive sleeve 107 during actuation of the actuator 109, the pivot member 120 rotates away from the stop surface 122. Once the activation switch 119 reaches the on state, the pivot member 120 can rotate further to accommodate further axial movement of the dose setting dial 108 in the distal direction relative to the housing 102, thereby maintaining the dose measuring system 101 powered on. In other embodiments, the activation switch 119 only needs to be moved to the on state for a short period of time to power on the dosage measurement system 101, and from that point on, the dosage measurement system 101 will remain powered on until the battery is depleted or for a set period of time, regardless of the subsequent position of the activation switch 119.

[0118] In some embodiments, the activation switch 119 is configured to move a first distance D1 from an off state to an on state (as shown in FIG. 3), and the sensor 114 is configured to move a second distance D2 from an idle position to a detection position (as shown in FIG. 3). The second distance D2 is longer than the first distance D1, such that the activation switch 119 reaches the on state before the sensor 114 reaches the detection position. The dose setting dial 108 must move axially the first distance D1 to move the activation switch 119 to the on state, and the dose setting dial 108 must move axially the second distance D2 to move the sensor 114 to the detection position. Both the first and second distances D1, D2 may extend in the axial direction of the drug delivery device 100.

[0119] 3, as soon as the pivot member 120 is biased against the dial sleeve 107, the activation switch 119 moves from an OFF state to an ON state to power the processor. However, it should be understood that in an alternative embodiment (not shown), the pivot member 120 rotates partially or fully after abutting against the dial sleeve 107, after which the activation switch 119 moves to an ON state and the processor is powered on. The point at which the activation switch 119 moves to the ON state is the switch point of the activation switch 119.

[0120] 3, when the sensing member 118 overlaps one of the features 112 in the axial direction of the device 100, the sensor 114 moves from an idle position to a sensing position, whereby when the sensor 114 is rotationally aligned with the feature 112, the sensing member 118 begins to rotate, which is detected by the processor. However, it should be understood that in an alternative embodiment (not shown), the sensing member 118 rotates partially or fully after abutting the feature 112, and then this movement is detected, and this position of the sensing member 118 is the switch point of the sensing member 118. In other words, the detection position of the sensor 114 may be the point where the switch point of the sensing member 118 is axially aligned with the feature 112.

[0121] As the dose setting dial 108 moves axially, the switch point of the activation switch 119 is reached and then the switch point of the sensor 114 is reached.

[0122] In some embodiments, the dose setting dial 108 must move axially a third distance D3 (shown in FIG. 3 ) to operate the dispensing mechanism 104 to dispense medication, e.g., to disengage the clutch 105. The third distance D3 may be longer than the first and second distances D1, D2 to help ensure that medication is not dispensed from the reservoir until after the activation switch 119 has been moved to an on state and the sensor 114 has been moved to a detection position.

[0123] In some embodiments, the support member 121 is rotatably coupled to components of the drug delivery device 100 via first and second bearings 125, 126. The first and second bearings 125, 126 may be radial bearings. However, it should be understood that one of the first and second radial bearings 125, 126 may be omitted.

[0124] In this embodiment, the support member 121 is rotatably coupled to a coupling member 127 via first and second bearings 125, 126. However, it should be understood that in other embodiments, the coupling member 127 is omitted.

[0125] The first bearing 125 includes a curved inner surface 121A of the support member 121 and a curved outer surface 127A of the connecting member 127. The inner and outer surfaces 121A, 127A may be cylindrical. The inner and outer surfaces 121A, 127A extend circumferentially about the longitudinal axis of the drug delivery device 100.

[0126] The inner and outer surfaces 121A, 127A engage to form a first radial bearing 125, which allows the inner surface 121A of the support member 121 to slide over the outer surface 127A of the connecting member 127, thereby allowing the support member 121 to rotate relative to the connecting member 127.

[0127] The second bearing 126 includes a circumferentially extending groove 121B in the support member 121 and a rib 127B in the coupling member 127. The rib 127B is received in the groove 121B. The rib 127B and the groove 121B form a second radial bearing 126, which allows the support member 121 to rotate relative to the coupling member 127, with the rib 127B rotating within the groove 121B. In some embodiments, the engagement of the rib 127B and the groove 121B axially holds the support member 121 and the coupling member 127 relative to one another.

[0128] It should be appreciated that in an alternative embodiment (not shown), the support member 121 may include a groove that receives a rib of the connecting member 127 to form the second bearing portion 126 .

[0129] The coupling member 127 is non-rotatably fixed to the dial sleeve 106. The coupling member 127 can be slidably attached to the sleeve 106, such that the coupling member 127 can move axially with the dose setting dial 108 during actuation. For example, the coupling member 127 can be slidably attached to a longitudinal member extending distally from the coupling member 127 and connected to an internal member of the medication delivery device 100. In another embodiment, the coupling member 127 is attached to the clutch 105, such that actuation of the dose setting dial 108 axially biases the coupling member 127, which in turn biases the clutch 105 axially into disengagement.

[0130] Optionally, device 100 further includes a pivot 128. In FIG. 14, pivot 128 is shown in the form of a pivot point 128A that includes a rounded protrusion 128A extending proximally from the proximal end of connecting member 127 (pivot point 128A is not shown in FIG. 13). Protrusion 128A abuts a distally facing generally flat surface of support member 121. In an alternative embodiment (not shown), a rounded protrusion is provided on the distally facing surface of support member 121 and abuts a proximally facing surface of connecting member 127.

[0131] The pivot 128 is configured to allow rotation of the dose setting dial 108 relative to the connecting member 127, for example due to rotation of the connecting member 127 relative to the dose setting dial 108 during dispensing of medication. The pivot 128 helps to minimize the contact area between the support member 121 and the connecting member 127, thus reducing friction therebetween.

[0132] The pivot 128 is configured such that when a user applies a force to the dose setting dial 108, for example by applying an off-center force to a peripheral edge of the dose setting dial 108, thereby biasing the dose setting dial 108 to tilt relative to the housing 102, the dose setting dial 108 is biased to tilt about the pivot 128. However, the first and second radial bearings 125, 126 are configured to resist such tilting of the dose setting dial 108, and thus the radial bearings 125, 126 help to keep the dose setting dial 108 aligned with the housing 102.

[0133] More specifically, it is desirable to prevent tilting of the dose setting dial 108 relative to the housing 102, which could otherwise cause misalignment of the sensor 114 relative to the feature 112. For example, during actuation, a user presses on an edge of the dose setting dial 108, which urges the dose setting dial 108 to tilt relative to the longitudinal axis of the medication delivery device 100, such that the proximal end of the dose setting dial 108 is no longer perpendicular to the longitudinal axis, but is instead now tilted relative to it. To help prevent this, the second bearing 126 is located distal to the first bearing 125. Thus, when a user applies a force to the dose setting dial 108 that tilts it, the second bearing 126 provides a counter force that prevents tilting of the dose setting dial 108. The location of the second support 126 away from the pivot 128 means that the reaction force that needs to be applied by the second support 126 to stabilize the dose setting dial 108 and prevent it from tilting is less than if the second support 126 were located closer to the pivot 128.

[0134] The second bearing 126 may be located radially outward of the first bearing 125, in other words further away from the longitudinal axis of the drug delivery device 100 than the first bearing 125. That is, the second bearing 126 may have a longer radius than the first bearing 125. In this way, when the dose setting dial 108 rotates while tilting, the counter torque exerted by the first bearing 125 is reduced compared to when the first bearing 125 has a larger diameter. This reduces friction resisting rotation of the dose setting dial 108. The second bearing 126 has a larger diameter than the first bearing 125 and provides support when the dose dial setting 108 tilts about the pivot axis 128.

[0135] Optionally, the support member 121 or another component may include the stop described above, which stop 122 against which the activation switch 119 abuts when in the off state.

[0136] Operation of the medication delivery device 100 will now be described. A user dials in the dose to be delivered by rotating the dose setting dial 108 in a second rotational direction relative to the housing 102, which correspondingly causes rotation of the dial sleeve 106 in the second rotational direction relative to the housing 102 until the desired dose is displayed in a dose window (not shown). A needle (not shown) is inserted into a patient's injection site.

[0137] To deliver a dose of medication, the user pushes the dose setting dial 108 axially distally into the housing 102. This causes a sensor 114 and an activation switch 119 attached to the dose setting dial 108 to move axially distally. The axial movement of the dose setting dial 108 first causes the activation switch 119 to abut against the drive sleeve 107, which moves the activation switch 119 to an on state, which in turn powers on the processor 115 of the dose measurement system 101.

[0138] Continued distal movement of the dose setting dial 108 moves the sensor 114 to a detection position where the sensor 114 overlaps the feature 112 in the axial direction of the drug delivery device 100, and the dosing mechanism 104 is then actuated to expel drug from the reservoir and deliver it through the needle. For example, the drug delivery device 100 may include a release mechanism that is activated to release the drive member when the dose setting dial 108 is moved distally to an axial position where the sensor 114 is in the detection position, or in other embodiments, when the dose setting dial 108 is moved further distally in the axial position (e.g., a third distance D3).

[0139] In this embodiment, movement of the dose setting dial 108 a third distance D3 relative to the housing 102 disengages the clutch 105, which moves the clutch 105 to a disengaged position. The dial sleeve 106 and drive sleeve 107 can then rotate relative to the housing 102 and dose setting dial 108 in a first rotational direction X under the force of the drive member to dispense medicament from the reservoir. In another embodiment (not shown), the clutch 105 is disengaged when the dose setting dial 108 is moved a second distance D2 relative to the housing 102, simultaneously with the sensor 114 reaching the detection position.

[0140] Rotation of the dial sleeve 106 relative to the housing 102 in a first rotational direction X during dispensing of medication is detected by a sensor 114, thereby enabling a processor 115 to determine the dose delivered by the medication delivery device 100. In particular, rotation of the dial sleeve 106 urges the continuous feature 112 against the sensing member 118, thereby repeatedly moving the sensing member 118 between an inactivated state (shown in FIG. 8 ) and an activated state (shown in FIG. 9 ).

[0141] The processor 115 is configured to determine the delivered dose based on the movement of the sensing member 118. For example, the processor 115 can be configured to count the number of times the sensing member 118 transitions from an inactivated state to an activated state and / or the number of times the sensing member 118 transitions from an activated state to an inactivated state. The memory 116A, 116B can be programmed with information or instructions that enable the processor 115 to convert the number of transitions to a delivered dose.

[0142] As the dial sleeve 106 rotates in the first rotational direction X, a portion of the leading edge 112A of the first feature 112 abuts the sensing member 118, urging the sensing member 118 from an inactive state to an active state, whereby the sensor 114 transitions from outputting a LOW signal to outputting a HIGH signal. This represents the beginning of the first coded region 123 and the end of the second coded region 124. As the dial sleeve 106 continues to rotate in the first rotational direction X, the feature 112 remains engaged with the sensing member 118, whereby the sensing member 118 remains in an active state. As the feature 112 begins to pass the sensor 114, the sensing member 118 begins to return toward the inactive state, while still engaging the feature 112. In some embodiments, the sensing member 118 is biased toward the inactive state by a biasing member (not shown), e.g., a spring.

[0143] As the dial sleeve 106 rotates further in the first direction of rotation X, the sensing member 118 reaches an inactive state, and thus the sensor 114 transitions from outputting a HIGH signal to outputting a LOW signal. This represents the end of the first coding region 123 and the beginning of the second coding region 124. The sensor 114 then aligns with the gap 113 adjacent to the profile 112, thus maintaining the sensing member 118 in an inactive state, and thus the sensor 114 outputs a LOW signal, and then the dial sleeve 106 rotates to a position where a portion of the front edge 112A of the second profile 112 adjacent to the first profile 112 abuts against the sensing member 118, urging the sensing member 118 from an inactive state to an active state, whereby the sensor 114 transitions again from outputting a LOW signal to outputting a HIGH signal.

[0144] Thus, rotation of the dial sleeve 106 in a first rotational direction X causes the sensor 114 to generate an oscillating signal, for example a square wave signal, which is input to the processor 115. The processor 115 then determines the angular displacement of the dial sleeve 106 using edge detection to determine the dose dispensed from the drug reservoir.

[0145] Movement of the sensing member 118 between the unactuated and actuated states is illustrated in FIGS. 10 and 12, which show schematic representations of the sensor 114 and feature 112. As shown in FIG.

[0146] The dial sleeve 106 includes a plurality of first and second coding regions 123, 124, which are arranged alternately around the rotation axis of the dial sleeve 106. Each first coding region 123 begins when the respective shape 112 abuts against the sensing member 118, thereby energizing the sensing member 118 to an activated state, thereby transitioning the sensor 114 to output a HIGH signal, and ends when the shape 112 passes the sensor 114, thereby transitioning the sensing member 118 back to an inactivated state, thereby transitioning the sensor 114 to output a LOW signal. Each second coding region 124 begins at a rotation position of the dial sleeve 106 where the sensing member 118 reaches an activated state where the sensor 114 outputs a LOW signal, and ends when the adjacent shape 112 abuts against the sensing member 118, thereby energizing the sensing member 118 to an inactivated state, thereby transitioning the sensor 114 to output a HIGH signal.

[0147] Thus, when the sensor 114 is aligned with the first coding region 123, the sensing member 118 is in an inactive state and the sensor 114 outputs a HIGH signal (or a LOW signal in alternative embodiments), and when the sensor 114 is aligned with the second coding region 124, the sensing member 118 is in an active state and the sensor 114 outputs a LOW signal (or a HIGH signal in the alternative embodiments described above), thereby enabling the sensor 114 to distinguish between the first and second coding regions 123, 124.

[0148] Each first coding region 123 subtends an angle around the axis of rotation of the dial sleeve 106, and each second coding region 124 subtends the same angle around the axis of rotation of the dial sleeve 106. This does not necessarily mean that the features 112 subtend the same angle around the axis of rotation of the dial sleeve 106 as the gaps 113 between the features 112, because the arrangement of the sensing element 118 and the features 112 is such that the sensing element 118 remains in an activated state even when the apex 112B of the feature 112 passes the apex 118A of the sensing element 118. For example, the trailing edge 112C of the feature 112, which generally faces in the circumferential direction opposite to the leading edge 112A, can still abut the sensing element 118 to prevent the sensing element 118 from returning to an inactivated state. This is known as "ON drag" and refers to the relative movement between engaged feature 112 and sensor 114 required for sensing member 118 to transition to an activated state and then for the sensing member to transition back to a deactivated state. In one embodiment, feature 112 and sensing member 118 are positioned such that engaged feature 112 must move 1 mm relative to sensing member 118 before sensing member 118 transitions back to a deactivated state. Once engaged and moved to an activated state by feature 112, sensing member 118 remains in the activated state for the duration of the 1 mm movement of feature 112.

[0149] In some embodiments, the size and / or shape of each feature 112 is adjusted to take into account the ON drag so that the first and second encoded regions 123, 124 remain equal in size. For example, the angle that each feature 112 subtends about the axis of rotation of the dial sleeve 106 can be reduced by the size of the ON drag (as shown by arrow D4 in FIGS. 11 and 12).

[0150] In some alternative embodiments (not shown), the sensor 114 outputs a HIGH signal when the sensing member 118 is deactivated and a LOW signal when the sensing member 118 is activated. In further embodiments, the sensor 114 outputs an analog signal responsive to the position of the sensing member 118, such as a signal below a predetermined value when the sensing member 118 is deactivated and above a predetermined value when the sensing member 118 is activated. In some embodiments, the signal is generally sinusoidal when the dial sleeve 106 rotates in the first rotational direction X.

[0151] In one embodiment, the processor 115 is configured to determine the dose dispensed from the reservoir by counting the number of LOW-to-HIGH and HIGH-to-LOW transitions of the signal output by the sensor 114. In some embodiments, this requires edge counting, e.g., positive and / or negative edge counting, of the signal generated by the sensor 114.

[0152] Thus, with a resolution equal to the angle subtended by each of the first and second coded regions 123, 124 about the axis of rotation of the dial sleeve 106, the processor 115 can determine the rotational displacement of the dial sleeve 106 during drug delivery. From this rotational displacement, the processor 115 can determine the amount of drug dispensed from the reservoir. The smaller the angle subtended by each of the first and second coded regions 123, 124 about the axis of rotation, the higher the resolution of the dose determination measurement.

[0153] The processor 115 can be configured to transmit the determined drug dosage and, if determined, timestamp information to another device, such as a computer (not shown). As mentioned above, the output 117 can be configured to transmit the information using a wireless communication ring. Alternatively, the dosage measurement system 101 can be connected to a computer (not shown) using a wired connection (not shown) to allow the information to be uploaded to the computer. The processor 115 can be configured to periodically transmit the information to the computer. In some embodiments, the dosage measurement system 115 can be used to monitor compliance with a particular dosage regime.

[0154] In this embodiment, the dial sleeve 106 includes 24 shaped portions 112. Thus, there are 24 first coded regions 123 and 24 second coded regions 124. Each coded region 123, 124 spans an angle of 7.5 degrees around the rotation axis of the dial sleeve 106.

[0155] 16A-18, another embodiment of a dose measuring system 201 is shown. The dose measuring system 201 is similar to the dose measuring system 101 described above with respect to the embodiment of Figures 2-15, like features have the same reference numbers, and is part of a drug delivery device (not shown) having the same features as those of Figures 2-15. However, the dose measuring system 201 differs in that it includes first and second sensors 214A, 214C. The dial sleeve 206 includes a plurality of features 212 separated by gaps 213, and the features 212 are configured to engage the first and second sensors 214A, 214C when the dial sleeve 206 rotates.

[0156] Each of the first and second sensors 214A, 214C may be of the same type as the sensor 114 of the embodiment described above with respect to Figures 2 and 15 and has a sensing member 218A, 218C that is movable between an inactivated state and an activated state, and therefore a detailed description will not be repeated hereinafter.

[0157] 2 and 15, the dial sleeve 206 includes a plurality of first and second coded regions 223, 224 that are alternately arranged about the axis of rotation of the dial sleeve 206. The first coded regions 223 are formed by portions of the respective features 212 and, when aligned with the sensing members 218A, 218C, bias the sensing members into an active state. The second coded regions 224 are formed between the first coded regions 223.

[0158] Each of the first and second sensors 214A, 214C generates a HIGH signal when the sensor 214A, 214C is aligned with one of the first coded regions 223 and generates a LOW signal when the sensor 214A, 214C is aligned with one of the second coded regions 224. Thus, each sensor 214A, 214C can distinguish between the first and second coded regions 223, 224 and generate a signal accordingly.

[0159] The first and second sensors 214A, 214C are offset such that, in use, rotation of the dial sleeve 206 in the first direction of rotation X causes one of the first encoder areas 223 to be aligned with the first sensor 214A while one of the second encoder areas 224 to be aligned with the second sensor 214C. Furthermore, further rotation of the dial sleeve 206 in the first direction of rotation X causes one of the second encoder areas 224 to be aligned with the first sensor 214A while one of the first encoder areas 223 to be aligned with the second sensor 214C. Thus, while the first sensor 214A detects one of the first encoding areas 223, the second sensor 214C is aligned with one of the second encoding areas 224, and while the second sensor 214C detects one of the first encoding areas 223, the first sensor 214A is aligned with one of the second encoding areas 224.

[0160] The relative positions of the first and second sensors 214A, 214C with respect to the first and second coded regions 223, 224 are shown in Figure 16A. In Figure 16A, the first sensor 214A is aligned with the first coded region 223, such that the first sensing member 218A is activated, but this is not shown in order to clearly show the respective positions of the sensors 214A, 214C with respect to the coded regions 223, 224.

[0161] In FIG. 16A, the features 212 and gaps 213 are shown diagrammatically for purposes of illustration, and FIG. 16A is provided to show the placement of the first and second encoded regions 223, 224 relative to the sensors 214A, 214C.

[0162] The first and second sensors 214A, 214C may be positioned such that for all rotational positions of the dial sleeve 206 in which the first sensor 214A is aligned with one of the first encoded areas 223, the second sensor 214C is aligned with one of the second encoded areas 224. Thus, during rotation of the dial sleeve 206, when the sensing member 218A of the first sensor 214A transitions from an inactivated state to an activated state, the sensing member 218C of the second sensor 214C transitions from an activated state to an inactivated state.

[0163] In some embodiments, the first and second sensors 214A, 214C are offset 165 degrees in a first rotational direction X about the axis of rotation of the drive sleeve 206.

[0164] The first and second sensors 214A, 214C may be positioned such that for all rotational positions of the dial sleeve 206 in which the first sensor 214A is aligned with one of the second coded regions 224, the second sensor 214C is aligned with one of the first coded regions 223. Thus, during rotation of the dial sleeve 206, when the sensing member 218A of the first sensor 214A transitions from an activated state to an inactivated state, the sensing member 218C of the second sensor 214C transitions from an inactivated state to an activated state.

[0165] A processor (not shown) is configured to determine a delivered dose based on the movement of the first and second sensing members 218A, 218C. For example, the processor can be configured to count the number of transitions of the sensing members 218A, 218C from an inactivated state to an activated state and / or the number of transitions of the sensing members 218A, 218C from an activated state to an inactivated state. The processor can be preprogrammed with information that enables the processor to convert the number of transitions into a determination of the dose delivered by the medication delivery device.

[0166] In one embodiment, the processor is configured to determine the delivered dose based on one of counting the transitions of the sensing members 218A, 218C from an inactive state to an active state or counting the transitions of the sensing members 218A, 218C from a second position to an inactive state. One such example is shown in FIG. 17, where the processor is configured to count the number of times that the signals 219A, 219C output from the first and second sensors 214A, 214C, respectively, transition from LOW to HIGH. This can be referred to as a positive edge count. In another example, the processor is configured to count the number of times that the signals 219A, 219C output from the first and second sensors 214A, 214C transition from HIGH to LOW. This can be referred to as a negative edge count.

[0167] Providing a first and second sensor 214A, 214C offset in the first rotational direction X advantageously means that the resolution of the dosage determination is improved compared to an embodiment having only a single sensor. In this embodiment, the resolution for a given size of feature 212 is doubled compared to an embodiment having only a single sensor. The size of feature 212 and thus the angle of each of the first and second coding regions 223, 224 can therefore be increased, resulting in a larger edge tolerance while achieving the same resolution as a single sensor configuration, as will be explained below. For example, if a first and second sensor 214A, 214C are used, the number of features 212 can be reduced to 12 while still achieving the same measurement resolution as the embodiment of 24 features 112 of Figures 2-15.

[0168] Providing twelve features 212 means that the first and second coded regions 223, 224 each subtend a 15 degree angle about the axis of rotation of the dial sleeve 206. If only a single sensor 114 is used and the processor only counts negative or positive edges, the resolution of the measurement is 30 degrees, which is the angle the dial sleeve 206 must rotate to make the signal output by the sensor go from HIGH to LOW (or LOW to HIGH in the negative edge counting embodiment). However, because first and second sensors 214A, 214C are used, the resolution is doubled, and thus is the same as the single sensor embodiment having 24 features. However, the advantage of using fewer larger features 212 (e.g., twelve features 212 in this embodiment, but one skilled in the art would recognize that a different number of features 212 can be used) is that a larger edge tolerance is achieved.

[0169] The edge tolerance is the maximum distance that the dial sleeve 206 must rotate (in either the first or second rotational direction X, Y) to align either of the sensors 214A, 214C with the transition between one of the first coded regions 223 and one of the second coded regions 224. Thus, in this embodiment, with 12 features 212, the maximum edge tolerance is 7.5 degrees. By comparison, in an embodiment with a single sensor 114 and 24 features 112, the edge tolerance is 3.75 degrees.

[0170] A larger edge tolerance is advantageous because it reduces the likelihood of false edge detection by the sensors 214A, 214C, which may otherwise occur due to mechanical tolerances, because in embodiments with a larger edge tolerance, the sensing members 218A, 218C are less likely to transition from one of the inactive and active states to the other of the first and second positions for a given rotational displacement of the dial sleeve 206. Thus, for example, a small amount of "play" or accidental rotation of the dial sleeve 206 relative to the housing 202 is less likely to cause the first and second sensors 214A, 214C to transition between outputting LOW / HIGH signals, which would otherwise result in false edge detection by the processor and thus measurement errors.

[0171] In some embodiments, the edge tolerance is at least 5 degrees, at least 7 degrees, and preferably the edge tolerance is at least 7.5 degrees.

[0172] In some embodiments, the first and second sensors 214A, 214C are attached to a dose setting dial (not shown) such that the sensors 214A, 214C are movable from an idle position to a detection position, similar to that described with respect to the embodiment of Figures 2-15.

[0173] The first and second sensors 214A, 214C can be positioned such that for all rotational positions of the dial sleeve 206, one of the first and second sensors 214A, 214C is aligned with the first encoding area 223 and the other of the first and second sensors 214A, 214C is aligned with the second encoding area 224. What this means is that when the dose setting dial 208 (not shown) is actuated by a user, thereby moving the first and second sensors 214A, 214C to a detection position, one of the first and second sensors 214A, 214C engages one of the shaped portions 212, thereby causing the sensing members 218A, 218C of said sensors 214A, 214C to move to an activated state, and therefore the signal output from said sensors 214A, 214C transitions from LOW to HIGH (or, in embodiments in which the sensors output the opposite signal, the other sensor outputs such a transition).

[0174] If this transition were counted and used to determine the dose dispensed from the reservoir, the determined dose would be greater than the actual dose dispensed. To compensate for this, in some embodiments, the processor is configured to ignore the first detected LOW-to-HIGH transition output from the sensors 214A, 214C because this transition was caused by axial movement of one of the sensors 214A, 214C to the detection position. Any other LOW-to-HIGH transitions are considered by the processor to determine the dispensed dose because they are not due to axial movement of the sensors 214A, 214C but are a result of the rotation of the dial sleeve 206 during medication dispensing.

[0175] In some embodiments, the dial sleeve 206 includes multiple coding periods 225, where each coding period 225 includes one of the first coding region 223 and the adjacent second coding region 224. In some embodiments, for a given rotational position of the dial sleeve 206, the first sensor 214A is aligned with a portion of one of the coding periods 225, and the second sensor 214C is aligned with a different portion of one of the coding periods 225. If each coding period 225 is considered to have a virtual period of 360 degrees, i.e., if the feature 212 is repeated every 360 degrees, the first and second sensors 214A, 214C can be offset by 180 degrees of the coding period 225.

[0176] In some embodiments, the offset angle of the first and second sensors 214A, 214C about the axis of rotation of the dial sleeve 206 is an odd integer multiple of the angle that each first encoded region 223 subtends about the axis of rotation of the drive sleeve 206. For example, if the first encoded region 223 subtends 15 degrees about the axis of rotation, the offset angle can be 15 degrees, 45 degrees, 75 degrees, 105 degrees, 135 degrees, 165 degrees, 195 degrees, 225 degrees, 255 degrees, 285 degrees, 315 degrees, or 345 degrees.

[0177] In one such embodiment, the first and second sensors 214A, 214C are offset by 11 times the angle subtended by each first encoded region 223 about the axis of rotation of the drive sleeve 206. The first and second sensors 214A, 214C are offset by 165 degrees about the axis of rotation of the drive sleeve 206.

[0178] The processor can be configured to determine the dose dispensed from the drug reservoir based on a signal output from one of the first and second sensors 214A, 214C and an inverse signal of the signal output from the other of the first and second sensors 214A, 214C. In one embodiment shown in FIG. 18, the processor is configured to determine the dose dispensed from the drug reservoir based on a superposition 220 of the signal from one of the first and second sensors 214A, 214C and an inverse signal from the other of the first and second sensors 214A, 214C. In this particular embodiment, the superposition 220 of the signal 219A output from the first sensor 214A and an inverse signal of the signal 219C output from the second sensor 214C.

[0179] The superposition 220 may be calculated by adding the first signal 219A and the inverse of the second signal 219C.

[0180] The processor is configured to determine the dose dispensed from the drug reservoir by comparing the overlap 220 to a first threshold 226 and a second threshold 227 that is higher than the first threshold 226. In one such embodiment, the processor counts the number of times the overlap 220 transitions from a value lower than the first threshold 226 to a value higher than the second threshold 227 and / or the number of times the overlap transitions from a value higher than the second threshold 227 to a value lower than the first threshold 226. This helps improve the accuracy of the dose determination by helping to remove errors such as sensor noise and switch bounce because if one of the first and second sensors 214A, 214C provides an erroneous reading, this will not cause the overlap 220 to transition in a manner that is counted by the processor in the dose determination calculation.

[0181] In this embodiment, the processor also counts the number of times the overlap 220 transitions from a value below the first threshold 226 to a value above the second threshold 227, and the number of times the overlap transitions from a value above the second threshold 227 to a value below the first threshold 226. This count is used to determine the dose dispensed from the reservoir. As previously described, in embodiments having sensors 214A, 214C that move axially on the actuator, the initial count is ignored.

[0182] The first threshold 226 can be a value such that when the first sensor 214A is aligned with the second encoded portion 224 and at the same time the second sensor 214C is aligned with the first encoded portion 223, the overlap 220 is below the first threshold 226 and is above the first threshold 226 otherwise. That is, for the overlap 220 to be below the first threshold 226, both the first signal 219A and the inverse of the second signal 219C must be LOW.

[0183] The second threshold 227 may be a value such that when the first sensor 214A is aligned with the first coded portion 223 and at the same time the second sensor 214C is aligned with the second coded portion 224, the overlap 220 is above the second threshold 227 and is below the second threshold 227 otherwise. That is, for the overlap 220 to be above the second threshold 227, both the first signal 219A and the inverse of the second signal 219C must be HIGH.

[0184] In some embodiments, when the overlap 220 is equal to or below the first threshold 226, the overlap 220 is in a LOW state L, and when the overlap 220 is equal to or above the second threshold 227, the overlap 220 is in a HIGH state H. When the overlap 220 is above the first threshold 226 but below the second threshold 227, the overlap 220 is in an UNDEFINED state. The processor may count the number of times the overlap 220 transitions from a LOW state to a HIGH state and / or from a HIGH state to a LOW state to determine the administered dose.

[0185] For example, for a certain rotational position of the dial sleeve 206, the signal 219A output from the first sensor 214A is assumed to be HIGH and the signal 219C output from the second sensor 214C is assumed to be LOW, whereby the inverse signal of the signal 219C output from the second sensor 214C is assumed to be HIGH, and thus both HIGH signals mean that the superimposed signal 220 is assumed to be above the second threshold 227 (superimposed 220 is assumed to be in a HIGH state H). However, the mechanical switch of the first sensor 214A may momentarily "bounce" thereby outputting a LOW reading. In such a situation, since the inverse signal is still HIGH, the superimposed 220 is below the second threshold 227 but still above the first threshold 226 (superimposed goes to an UNDEFINED state). The superimposed signal 220 transitions below the first threshold 226 and is therefore counted by the processor to determine the administered dose only when both the signal 219A output from the first sensor 214A and the inverse signal of the signal 219C output from the second sensor 214C are both LOW (at which point the superimposed 220 transitions to a LOW state L and the entire transition from HIGH to LOW is counted by the processor as one increment in the administered dose determination). Thus, switch bounce is not counted by the processor in the dose dosing calculation and therefore does not contribute to an erroneous dose determination. Alternatively, if after a "bounce" the first sensor 214A instead outputs a HIGH reading again, the superimposed 220 transitions back to a HIGH state H, which is not counted by the processor as an increment. 4. This is because the overlap was previously in a HIGH state before moving to the UNDEFINED state, and therefore did not transition from a LOW state L to a HIGH state H.

[0186] In some embodiments, when the dial sleeve 206 reaches the zero position and finishes rotating, thereby dispensing the programmed dose from the reservoir, the first and second sensors 214A, 214B are aligned with their respective particular coded regions 223, 224 for longer than when the dial sleeve 206 rotates and the first and second sensors 214A, 214C are aligned with consecutive coded regions 223, 224. This is illustrated in Figure 18, which shows that the signals 219A, 219C output from the first and second sensors 223, 224 remain in the HIGH and LOW states (and thus the overlap 220 remains in the HIGH state) for a longer period of time after the last transition between the first and second coded regions 223, 224 detected by the sensors 214A, 214C occurs during the rotation of the dial sleeve 206 (transition number 8 in the example of Figure 18). In FIG. 18, the final transition after transition number 8 is due to the actuator, in this case the dose setting dial 208, moving proximally away from its actuated position, causing the sensors 214A, 214C to move out of the detection position and return to the idle position and thus no longer engage the feature 212.

[0187] Thus, the processor may determine that the dial sleeve 206 has stopped rotating and thus a dose has been dispensed if the first sensor 214A and / or the second sensor 214C remain aligned with one of the first and second encoded regions 223, 224 for more than a predetermined amount of time. The predetermined amount of time may be selected to be longer than the amount of time that either of the first and second encoded regions 223, 224 remain aligned with one of the first and second sensors 214A, 214C while the dial sleeve 206 rotates during operation of the dispensing mechanism to dispense medication from the reservoir.

[0188] If the processor determines that the dose has been administered, the processor may perform one or more actions, such as indicating to a user that the dose has been administered, for example via a user interface such as an LED, speaker, or screen, or by sending a signal to display such information on a separate device, storing and / or transmitting data regarding the administered dose, ignoring any further transitions between the first and second coding regions detected by the sensor so that such further transitions are not used to calculate the administered dose, and / or powering down the dose measurement system to conserve energy.

[0189] 16B, 19 and 20, there is shown another embodiment of a dose measuring system 301. This dose measuring system 301 is similar to the dose measuring system 201 described above with respect to the embodiment of Figures 16A, and 17-18, like features have the same reference numerals, and is part of a drug delivery device (not shown) having the same features as in Figures 2-15. However, the dose measuring system 301 differs in that in addition to including first and second sensors 314A, 314C, the dose measuring system 301 further includes third and fourth sensors 314B, 314D.

[0190] The dial sleeve 306 includes a plurality of features 312 separated by gaps 313, and the features 312 are configured to engage first, second, third, and fourth sensors 314A, 314C, 314B, 314D as the dial sleeve 306 rotates.

[0191] Each of the first, second, third and fourth sensors 314A, 314C, 314B, 314D may be of the same type as the first and second sensors 214A, 214C of the embodiment described above with respect to Figures 16 and 17-18, and each have a first, second, third and fourth sensing member 318A, 318C, 318B, 318D, respectively, that are movable between an inactivated state and an activated state, and therefore a detailed description will not be repeated hereinafter.

[0192] Similar to the embodiment of Figures 16A and 17-18, the dial sleeve 306 includes a plurality of first and second coded regions 323, 324 that are alternately arranged about the axis of rotation of the dial sleeve 306. The first coded regions 323 are formed by portions of the respective shaped portions 312 and, when aligned with the sensing members 318A, 318C, 318B, 318D, bias the sensing members into an activated state. The second coded regions 324 are formed between the first coded regions 323.

[0193] Each of the first, second, third, and fourth sensors 314A, 314C, 314B, 314D generates a HIGH signal when the sensor 314A, 314C, 314B, 314D is aligned with one of the first coded regions 323 and generates a LOW signal when the sensor 314A, 314C, 314B, 314D is aligned with one of the second coded regions 324. Thus, each sensor 314A, 314C, 314B, 314D can distinguish between the first and second coded regions 323, 324 and generate a signal accordingly.

[0194] Similar to the embodiment of the dosage measuring system 201 of Figures 16A and 17-18, the first and second sensors 314A, 314C are offset such that, in use, rotation of the dial sleeve 306 in the first rotational direction X causes one of the first encoder areas 323 to be aligned with the first sensor 314A while one of the second encoder areas 324 to be aligned with the second sensor 314C. Furthermore, further rotation of the dial sleeve 306 in the first rotational direction X causes one of the second encoder areas 324 to be aligned with the first sensor 314A while one of the first encoder areas 323 to be aligned with the second sensor 314C. Thus, while the first sensor 314A detects one of the first encoding areas 323, the second sensor 314C is aligned with one of the second encoding areas 324, and while the second sensor 314C detects one of the first encoding areas 323, the first sensor 314A is aligned with one of the second encoding areas 324.

[0195] The third and fourth sensors 314B, 314D are offset from the first and second sensors 314A, 314C in the direction of rotation of the dial sleeve 306.

[0196] In some embodiments, the first and second sensors 314A, 314C are offset 165 degrees in a first rotational direction X about the axis of rotation of the drive sleeve 306. In some embodiments, the third sensor 314B is offset 90 degrees from the first sensor 314A in the first rotational direction X about the axis of rotation, and the fourth sensor 314D is offset 105 degrees from the first sensor 314A in the second rotational direction about the axis of rotation.

[0197] In Figure 16B, the features 312 and gaps 313 are shown diagrammatically for illustrative purposes, and Figure 16B is provided to show the positioning of the first and second encoded regions 323, 324 relative to the sensors 314A, 314B, 314C, 314D.

[0198] The third sensor 314B is arranged such that, in use, a rotation of the dial sleeve 306 in the first direction of rotation X causes one of the first encoder areas 323 to be aligned with the first sensor 314A, while another one of the first encoder areas 323 is aligned with the third sensor 314B. Furthermore, a further rotation of the dial sleeve 306 in the first direction of rotation X causes one of the second encoder areas 324 to be aligned with the first sensor 314A, while another one of the second encoder areas 324 is aligned with the third sensor 314B. Thus, while the first sensor 314A detects one of the first encoding areas 323, the third sensor 314B is aligned with another of the first encoding areas 323, and while the first sensor 314A detects one of the second encoding areas 324, the third sensor 314B is aligned with another of the second encoding areas 324.

[0199] The third sensor 314B can be positioned such that for all rotational positions of the dial sleeve 306 where the first sensor 314A is aligned with one of the first encoded areas 323, the third sensor 314B is aligned with one of the first encoded areas 323. Thus, during rotation of the dial sleeve 306, when the sensing member 318A of the first sensor 314A transitions from an inactive state to an active state, the sensing member 318B of the third sensor 314B transitions from an inactive state to an active state. Similarly, the third sensor 314B can be positioned such that for all rotational positions of the dial sleeve 306 where the first sensor 314A is aligned with one of the second encoded areas 324, the third sensor 314B is aligned with one of the second encoded areas 324. Thus, when the sensing member 318A of the first sensor 314A transitions from an activated state to a deactivated state during rotation of the dial sleeve 306, the sensing member 318B of the third sensor 314B transitions from an activated state to a deactivated state.

[0200] The fourth sensor 314D is arranged such that, in use, a rotation of the dial sleeve 306 in the first direction of rotation X causes one of the first encoder areas 323 to be aligned with the second sensor 314C, while another one of the first encoder areas 323 is aligned with the fourth sensor 314D. Furthermore, a further rotation of the dial sleeve 306 in the first direction of rotation X causes one of the second encoder areas 324 to be aligned with the second sensor 314C, while another one of the second encoder areas 323 is aligned with the fourth sensor 314D. Thus, while the second sensor 314C detects one of the first encoding areas 323, the fourth sensor 314D is aligned with another of the first encoding areas 323, and while the second sensor 314C detects one of the second encoding areas 324, the fourth sensor 314D is aligned with another of the second encoding areas 324.

[0201] The fourth sensor 314D can be positioned such that for all rotational positions of the dial sleeve 306 where the second sensor 314C is aligned with one of the first coding areas 323, the fourth sensor 314D is aligned with one of the first coding areas 323. Thus, during rotation of the dial sleeve 306, when the sensing member 318C of the second sensor 314C transitions from an inactive state to an active state, the sensing member 318D of the fourth sensor 314D transitions from an inactive state to an active state. Similarly, the fourth sensor 314D can be positioned such that for all rotational positions of the dial sleeve 306 where the second sensor 314C is aligned with one of the second coding areas 324, the fourth sensor 314D is aligned with one of the second coding areas 324. Thus, when the sensing member 318C of the second sensor 314C transitions from an activated state to a deactivated state during rotation of the dial sleeve 306, the sensing member 318D of the fourth sensor 314D transitions from an activated state to a deactivated state.

[0202] In some embodiments, the dial sleeve 306 includes multiple coding periods 325, where each coding period 325 includes one of the first coding region 323 and the adjacent second coding region 324. In some embodiments, for a given rotational position of the dial sleeve 306, the first sensor 314A is aligned with a portion of one of the coding periods 325, and the second sensor 314C is aligned with a different portion of one of the coding periods 325. If each coding period 325 is considered to have a virtual period of 360 degrees, i.e., if the feature 312 is repeated every 360 degrees, the first and second sensors 314A, 314C can be offset by 180 degrees of the coding period 325.

[0203] The third sensor 314B is in phase with the first sensor 314A such that the sensors 314B, 314A are aligned with the same portion of their respective coding periods 325, and thus the offset of the coding periods 325 is zero degrees. The fourth sensor 314D is in phase with the second sensor 314C such that the sensors 314D, 314C are aligned with the same portion of their respective coding periods 325, and thus the offset of the coding periods 325 is zero degrees.

[0204] The third sensor 314B provides redundancy in case the first sensor 314A fails to detect the coded regions 323, 324 due to a detection error, and allows filtering of unlikely detection events. The fourth sensor 314D provides redundancy in case the second sensor 314C fails to detect the coded regions 323, 324 due to a detection error, and allows filtering of unlikely detection events.

[0205] The processor can be configured to determine the dose dispensed from the drug reservoir based on a superposition of the signals 319A, 319B output from the first and third sensors 314A, 314B with the inverse signals of the signals 319C, 319D output from the second and fourth sensors 314C, 314D, or a superposition of the signals 319C, 319D output from the second and fourth sensors 314C, 314D with the inverse signals of the signals 319A, 319B output from the first and third sensors 314A, 314B.

[0206] In the particular embodiment shown in FIG. 20, the dosage is determined based on a superposition 320 of signals 319A, 319B output from the first and third sensors 314A, 314B and the inverse signals 319C, 319D output from the second and fourth sensors 314C, 314D.

[0207] The superposition 320 may be calculated by adding the first and third signals 319A, 319B and the inverses of the second and fourth signals 319C, 319D.

[0208] The processor is configured to determine the dose dispensed from the drug reservoir by comparing the overlap 320 to a first threshold 326 and a second threshold 327 that is higher than the first threshold 326 .

[0209] In one such embodiment, the processor counts the number of times the overlap 320 transitions from a value below the first threshold 326 to a value above the second threshold 327, and / or the number of times the overlap transitions from a value above the second threshold 327 to a value below the first threshold 326. This helps improve the accuracy of the dosage determination by helping to remove errors such as sensor noise and switch bounce, because if one or two of the sensors 314A, 314B, 314C, 314D provide an erroneous reading, this will not cause the overlap 320 to transition in a manner that will be counted by the processor in the dosage determination calculation.

[0210] In this embodiment, the processor also counts the number of times the overlap 320 transitions from below the first threshold 326 to above the second threshold 327, and from above the second threshold 327 to below the first threshold 326. This count is used to determine the dose dispensed from the reservoir. As previously described, in embodiments having sensors 314A, 314B, 314C, 314D that move axially on an actuator that operates an activation switch 332, the first count is ignored. The activation switch 332 signal 333 is shown in FIG. 20.

[0211] The first threshold 326 may be a value such that at least three of the signals 319A, 319B output from the first and third sensors 314A, 314B and the inverse signals 319C, 319D output from the second and fourth sensors 314C, 314D must be LOW for the overlap 320 to fall below the first threshold 326.

[0212] The second threshold 327 may be a value such that at least three of the signals 319A, 319B output from the first and third sensors 314A, 314B and the inverse signals 319C, 319D output from the second and fourth sensors 314C, 314D must be HIGH for the overlap 320 to exceed the second threshold 327.

[0213] In some embodiments, when the overlap 320 is equal to or below the first threshold 326, the overlap 320 is in a LOW state L, and when the overlap 320 is equal to or above the second threshold 327, the overlap 320 is in a HIGH state H. When the overlap 320 is above the first threshold 326 but below the second threshold 327, the overlap 320 is in an UNDEFINED state. The processor may count the number of times the overlap 320 transitions from a LOW state to a HIGH state and / or from a HIGH state to a LOW state to determine the administered dose.

[0214] For example, for a particular rotational position of the dial sleeve 306, the signals 319A, 319B output from the first and third sensors 314A, 314C are assumed to be HIGH, and the inverse signals 319C, 319D output from the second and fourth sensors 314B, 314D are assumed to be HIGH, thus the four HIGH signals mean that the superimposed signal 320 is assumed to be equal to or above the second threshold 327 (the superimposed 320 is assumed to be in a HIGH state H). However, the mechanical switch of the first sensor 314A may momentarily "bounce" thereby outputting a LOW reading. In such a situation, the superimposed 320 is still equal to or above the second threshold 327, and thus the state of the superimposed 320 remains in a HIGH state H. Thus, the superimposed 320 does not transition to a LOW state, so the processor does not count an increment for the calculation of the administered dose determination. Indeed, if the mechanical switch of the fourth sensor 314D also “bounces” at the same time, thereby outputting a HIGH reading, and thus the inverse of signal 319D is LOW, then the superposition 320 will contain two LOW signal inputs and two HIGH signal inputs, and therefore the superposition 320 will be greater than the first threshold 326 but less than the second threshold 327. The superposition 320 will thus be in the UNDEFINED state U.

[0215] The superimposed signal 320 transitions to a value equal to or lower than the first threshold 326 and is therefore counted by the processor in determining the administered dose only when at least three of the following occur: the first sensor 314A outputs a signal 319A that is LOW, the third sensor 314B outputs a signal 319B that is LOW, the second sensor 314C outputs a signal 319C that is HIGH so that the inverse signal is LOW, and the fourth sensor 314D outputs a signal 319D that is HIGH so that the inverse signal is LOW (at which point the superimposed 320 transitions to a LOW state L and the entire transition from HIGH to LOW is counted by the processor as one increment in the administered dose determination).

[0216] Thus, multiple switch bounces or other such errors are not counted by the processor in the dose dosing calculation and therefore do not contribute to erroneous dose determinations.

[0217] Referring now to Figures 16C and 21, there is shown another embodiment of a dose measuring system 401. The dose measuring system 401 of Figure 16C is similar to the dose measuring system 301 of the embodiment of Figures 16B, 19 and 20, and like features have the same reference numbers. What differs is that the features 412 and gaps 413 of the dial sleeve 406 have different sizes, and the first, second, third and fourth sensors 414A, 414C, 414B, 414D are positioned differently relative to the first and second coding regions 423, 424.

[0218] The dial sleeve 406 includes half the number of features 412 and gaps 413 as the dial sleeve 306 of Figures 16B, 19, and 20. In this embodiment, the dial sleeve 406 includes six features 412 and six gaps 413.

[0219] Similar to the embodiment of Figures 16A and 17-18 and the embodiment of Figures 16B and 19-20, the dial sleeve 406 includes a plurality of first and second coded regions 423, 424 that are alternately arranged about the axis of rotation of the dial sleeve 406. The first coded regions 423 are formed by portions of the respective shaped portions 412 and, when aligned with the sensing members 418A, 418C, 418B, 418D, bias the sensing members into an active state. The second coded regions 424 are formed between the first coded regions 423.

[0220] Each of the first, second, third, and fourth sensors 414A, 414C, 414B, 414D generates a HIGH signal when the sensor 414A, 414C, 414B, 414D is aligned with one of the first coded regions 423 and generates a LOW signal when the sensor 414A, 414C, 414B, 414D is aligned with one of the second coded regions 424. Thus, each sensor 414A, 414C, 414B, 414D can distinguish between the first and second coded regions 423, 424 and generate a signal accordingly.

[0221] Similar to the embodiment of the dosage measuring system 201 of Figures 16A and 17-18 and the embodiment of Figures 16B and 19-20, the first and second sensors 414A, 414C are offset such that, in use, rotation of the dial sleeve 406 in a first rotational direction X aligns one of the first encoder areas 423 with the first sensor 414A while aligning one of the second encoder areas 424 with the second sensor 414C. Further rotation of the dial sleeve 406 in the first rotational direction X aligns one of the second encoder areas 424 with the first sensor 414A while aligning one of the first encoder areas 423 with the second sensor 414C. Thus, while the first sensor 414A detects one of the first encoding areas 423, the second sensor 414C is aligned with one of the second encoding areas 424, and while the second sensor 414C detects one of the first encoding areas 423, the first sensor 414A is aligned with one of the second encoding areas 424.

[0222] The third and fourth sensors 414B, 414D are offset from the first and second sensors 414A, 414C in the direction of rotation of the dial sleeve 406. In Figure 16C, the features 412 and gaps 413 are shown diagrammatically for purposes of illustration, and Figure 16C is provided to show the location of the first and second coding regions 423, 424 relative to the sensors 414A, 414B, 414C, 414D.

[0223] In some embodiments, the first and third sensors 414A, 414B are offset 165 degrees in a first rotational direction X about the axis of rotation of the drive sleeve 406. In some embodiments, the second sensor 414C is offset 90 degrees from the first sensor 414A in the first rotational direction X about the axis of rotation, and the fourth sensor 414D is offset 105 degrees from the first sensor 414A in the second rotational direction about the axis of rotation.

[0224] The third sensor 414B is positioned such that when the dial sleeve 406 is rotated such that the first sensor 414A is aligned with the transition between the encoded regions 423, 424 and the second sensor 414C is aligned with the transition between the encoded regions 423, 424, the third sensor 414B is not aligned with the transition between the encoded regions 423, 424 (i.e., the third sensor 414B is only aligned with one of the first or second encoded regions 423, 424). In some embodiments, when the dial sleeve 406 is in such a position, the third sensor 414B is equidistant from the two nearest transitions between the first and second encoded regions 423, 424.

[0225] The fourth sensor 414D is positioned such that when the dial sleeve 406 is rotated such that the first sensor 414A is aligned with the transition between the encoded regions 423, 424 and the second sensor 414C is aligned with the transition between the encoded regions 423, 424, the fourth sensor 414D is not aligned with the transition between the encoded regions 423, 424 (i.e., the fourth sensor 414D is only aligned with one of the first or second encoded regions 423, 424). In some embodiments, when the dial sleeve 406 is in such a position, the fourth sensor 414D is equidistant from the two nearest transitions between the first and second encoded regions 423, 424.

[0226] The third and fourth sensors 414B, 414D are offset such that, in use, rotation of the dial sleeve 406 in the first direction of rotation X causes one of the first encoder areas 423 to be aligned with the third sensor 414B, while one of the second encoder areas 424 to be aligned with the fourth sensor 414D. Furthermore, further rotation of the dial sleeve 406 in the first direction of rotation X causes one of the second encoder areas 424 to be aligned with the third sensor 414B, while one of the first encoder areas 423 to be aligned with the fourth sensor 414D. Thus, while the third sensor 414B detects one of the first encoding areas 423, the fourth sensor 414D is aligned with one of the second encoding areas 424, and while the fourth sensor 414D detects one of the first encoding areas 423, the third sensor 414B is aligned with one of the second encoding areas 424.

[0227] In some embodiments, when the first sensor 414A is aligned with the transition between the encoded regions 423, 424, the second sensor 414C is aligned with the transition between the encoded regions 423, 424, and when the third sensor 414B is aligned with the transition between the encoded regions 423, 424, the fourth sensor 414D is aligned with the transition between the encoded regions 423, 424.

[0228] In some embodiments, the dial sleeve 406 includes multiple coding periods 425, where each coding period 425 includes one of a first coding region 423 and an adjacent second coding region 424. In some embodiments, for a given rotational position of the dial sleeve 406, the first, second, third, and fourth sensors 414A, 414C, 414B, 414D are each all aligned with different portions of a respective coding period 425.

[0229] If each coding period 425 is considered to have a virtual period of 360 degrees, i.e., if the feature 412 is repeated every 360 degrees, then the first and second sensors 414A, 414C may be offset by 180 degrees of the coding period 425. The third and fourth sensors 414B, 414D may be offset by 180 degrees of the coding period 425.

[0230] In some embodiments, the third sensor 414B can be offset 90 degrees relative to one of the first and second sensors 414A, 414C and 270 degrees relative to the other of the first and second sensors 414A, 414C. The fourth sensor 414B can be offset 270 degrees relative to the one of the first and second sensors 414A, 414C and 90 degrees relative to the other of the first and second sensors 414A, 414C.

[0231] In this embodiment, the third sensor 414B is offset 270 degrees from the first sensor 414A and 90 degrees from the second sensor 414C. The fourth sensor 414D is offset 90 degrees from the first sensor 414A and 270 degrees from the second sensor 414C.

[0232] The first, second, third, and fourth sensors 414A, 414C, 414B, 414D are all out of phase with one another so that the processor can determine whether the dial sleeve 406 is rotating in a first rotational direction or a second rotational direction. As the dial sleeve 406 rotates, only one of the sensors 414A, 414C, 414B, 414D at a time is aligned with the positive edge transition from the first coded region 423 to the second coded region 424.

[0233] For example, when the dial sleeve 406 is rotated in the first rotation direction X, the order of activation is the first sensor 414A, the third sensor 414B, the second sensor 414C, and then the fourth sensor 414D. That is, one of the shapes 212 abuts against the sensing member 418A of the first sensor 414A to move the sensing member 418A from an inactive state to an active state, one of the shapes 212 abuts against the sensing member 418B of the third sensor 414B to move the sensing member 418B from an inactive state to an active state, one of the shapes 212 abuts against the sensing member 418C of the second sensor 414C to move the sensing member 418C from an inactive state to an active state, and then one of the shapes 212 abuts against the sensing member 418D of the fourth sensor 414D to move the sensing member 418D from an inactive state to an active state.

[0234] Conversely, when the dial sleeve 406 is rotated in the second rotation direction, the order of activation is the first sensor 414A, the fourth sensor 414D, the second sensor 414C, and then the third sensor 414B. That is, one of the shapes 212 abuts against the sensing member 418A of the first sensor 414A to move the sensing member 418A from an inactive state to an active state, one of the shapes 212 abuts against the sensing member 418D of the fourth sensor 414D to move the sensing member 418D from an inactive state to an active state, one of the shapes 212 abuts against the sensing member 418C of the second sensor 414C to move the sensing member 418C from an inactive state to an active state, and then one of the shapes 212 abuts against the sensing member 418B of the third sensor 414B to move the sensing member 418B from an inactive state to an active state.

[0235] Therefore, the processor can determine the rotation direction of the dial sleeve 406 based on the order of activation of the sensors 414A, 414B, 414C, and 414D. In some embodiments, the determination of the rotation direction can be performed starting from any of the sensors 414A, 414B, 414C, and 414D. For example, when the second sensor 414C is activated, if the next activation is the fourth sensor 414D, the processor can determine that the dial sleeve 406 is rotating in the first rotation direction X, and if the next activation is the third sensor 414B, the processor can determine that the dial sleeve 406 is rotating in the second rotation direction.

[0236] If the processor determines that the rotation is in the second direction, the processor may be configured to ignore the detected rotation of the dial sleeve 406 in determining the dispensed dose. For example, when the dial sleeve 406 rotates in the first direction X during dispensing of a medication, the dial sleeve 406 reaches a "zero" position when the dial sleeve 406 rotates completely in the first direction X and all the dose is dispensed. However, when the dial sleeve 406 reaches the "zero" position, the dial sleeve 406 may rotate slightly past the "zero" position and then rotate back again in the second direction (sometimes referred to as "backspin"), which may activate another one of the sensors 414A, 414B, 414C, 414D. If this additional rotation is incorporated into the calculation of the dispensed dose, the measurement will be higher than the actual dose delivered. However, because the rotation of the dial sleeve was in the second direction, this rotation may be ignored in the calculation. The dial sleeve 406 can also move in a second rotational direction during rotation of the dose setting dial 408 to "dial" the dose.

[0237] It should be noted that in an alternative embodiment (not shown), one of the third and fourth sensors 414B, 414D is omitted, but in such an arrangement the processor can still determine the direction of rotation of the dial sleeve 406 based on readings from the remaining three sensors.

[0238] In the embodiments described above, the sensors 114, 214A, 214B, 214C, 214D, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D are mechanically actuated. However, it should be understood that in some embodiments, different types of sensors are used. In an alternative embodiment shown in FIG. 22, the dose measurement system includes one or more optical sensors 514. The or each optical sensor 514 may include a light gate. The dial sleeve 506 may include multiple features 512 separated by gaps 513. As the dial sleeve 506 rotates, successive features 512 align with the light gate and break the light beam of the light gate, thereby causing the sensor 514 to detect the rotation of the dial sleeve 506. In embodiments having multiple sensors 514, the sensors 514 may be positioned as described above with respect to any of FIGS. 16A-16C.

[0239] In other embodiments (not shown), the sensors 114, 214A, 214B, 214C, 214D, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514 may be, for example, magnetic or capacitive sensors. For example, in one embodiment (not shown), the first coding region may include a plurality of magnetic material portions attached to a proximal end of the dial sleeve and spaced apart about the axis of rotation of the dial sleeve, and the second coding region is formed as a space between adjacent magnetic material portions. The or each sensor includes a magnetic sensor, for example a Hall sensor, that detects the presence of magnetic material. In yet another embodiment (not shown), the first coded region may include a plurality of reflective material portions attached to a proximal end of the dial sleeve and spaced apart about the axis of rotation of the dial sleeve, and the second coded region is formed as spaces between adjacent reflective material portions, or alternatively as portions of material having different optical properties, such as being less reflective, than the first coded region. The or each sensor includes an optical sensor capable of distinguishing between the optical properties of the first and second coded regions.

[0240] In the above-described embodiment, the dose setting dial 108 forms an actuator that can move axially relative to the housing to operate the dispensing mechanism to dispense the medicament from the reservoir. However, in an alternative embodiment (not shown), the actuator instead includes a component that can move relative to the dose setting dial to dispense the medicament. In one embodiment (not shown), the actuator includes a push button that is attached to the dose setting dial and is slidable axially relative to the dose setting dial to operate the dispensing mechanism to dispense the medicament from the reservoir. During operation, the push button is configured to move axially relative to the housing and the dial sleeve a short distance. This movement occurs when a user applies a force to the push button, for example when the user presses the push button along an axis in a distal direction towards the injection site. This axial movement of the push button disengages the clutch, which moves the clutch to a disengaged position, thus allowing the dial sleeve and the drive sleeve to rotate in a first rotational direction relative to the housing and the dose setting dial under the force of the drive member to dispense the medicament from the reservoir. The push button may be located at a proximal end of the dose setting dial. The push button may be biased in a proximal direction. In some embodiments, the sensor 114, 214A, 214B, 214C, 214D, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514 is attached to the push button and moves relative to the housing and the dose setting dial. The sensor may move from a rest position to a detection position when the push button is actuated, which may also actuate an activation switch to an on state and power the dose measurement system in a similar manner as described above. The activation switch may reach an on state before the sensor reaches the detection position.

[0241] In some alternative embodiments (not shown), the sensor 114, 214A, 214B, 214C, 214D, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514 does not move axially with the actuator. The sensor may be in a sensing position prior to actuation of the actuator. In some embodiments (not shown), the sensor is fixed relative to the housing.

[0242] In the above-described embodiments, the coded regions are provided on the dial sleeve 106, 206, 306, 406, 506 and the or each sensor 114, 214A, 214B, 214C, 214D, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514 is configured to detect rotation of the dial sleeve 106, 206, 306, 406, 506. However, in an alternative embodiment (not shown), the coded regions (e.g. features and gaps) are provided on the drive sleeve 107 and the or each sensor 114, 214A, 214B, 214C, 214D, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514 is configured to detect rotation of the drive sleeve 107. In further embodiments (not shown), the coding region is provided on another component and the or each sensor 114, 214A, 214B, 214C, 214D, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514 is configured to detect rotation of said component. In some embodiments (not shown), the component is a component of a medication dispensing mechanism.

[0243] In some embodiments (not shown), one or more of the signals 219A, 219C, 319A, 319B, 319C, 319D, 419A, 419B, 419C, 419D output from the sensor are filtered to improve the accuracy of the measurement, for example, by removing noise from the signal. In some embodiments, the signal is filtered by a low pass filter. In some embodiments, the signal is filtered before being input to the processor. In other embodiments, the processor filters the signal.

[0244] Electromechanical switches contain electrical contacts that can deflect for a short period of time after being switched on or off. This can lead to multiple fast signal pulses, called bounce, after the original signal edge. Bounce can be reduced by switches with contact designs that minimize oscillation. Additionally, as mentioned above, the signal can be filtered by electronics or software as long as the bounce duration is shorter than the normal signal pulse duration. This filtering is called debouncing.

[0245] It would be advantageous to improve power management, thereby allowing the use of smaller batteries with lower capacity, resulting in a more compact dosage measurement system. Small batteries are more susceptible to peak currents, so it would be advantageous to reduce the peak currents.

[0246] Improved power management may include reduced energy consumption during shelf life. In one such embodiment (not shown), the battery is mechanically disconnected during shelf life by a strip, e.g., a paper or plastic strip. The strip can be pulled out by the user to activate the dose measurement system. In another embodiment (not shown), the battery is mechanically disconnected by a mechanism. When the actuator is pressed for the first time, a component breaks, allowing a permanent connection between the electronics and the battery. In yet another embodiment (not shown), the battery is mechanically disconnected by a life switch on the PCB. This activation may be irreversible. In yet another embodiment, the electronics are kept in a strong power saving mode until the actuator is pressed for the first time. In yet another embodiment (not shown), the battery is inserted into the device immediately before first use. In some embodiments (not shown), the button is replaceable or rechargeable.

[0247] The processor may have a minimum sampling interval. In some embodiments, the shortest gap was about 700 μsec. In such embodiments, a sampling interval of 500 μsec was sufficient to adequately detect such short gaps. In such embodiments, the minimum sampling frequency to detect all signal edges was:

number

[0248] Using mechanical switches instead of optical gates / barriers reduces energy consumption because in some embodiments the state of the mechanical switch can be detected with less than 100 μA per switch. If the signal quality is good, further energy savings can be achieved by detecting edges at every interruption. This means that the switch can be connected to an interruption port of the processor. The interruption port can be selected to be triggered by the rising / falling edge of the switch state, allowing the processor to wait in a low energy state instead of a permanent polling operation that is energy intensive at a high sampling frequency.

[0249] In an embodiment where an optical gate / barrier is used, during an estimated sampling period of 500 μsec, the IR-LEDs may be switched on (rise time typically <10 μsec at 100k Ohms, same falloff), the ADC can acquire (2 μsec) and convert (5 μsec), and the rest of the time the IR-LEDs can be switched off to save power. This has been found to reduce power.

[0250] In some embodiments (not shown), the drug delivery device includes a user interface, e.g., one or more LEDs, to prompt the user or provide an indication to the user. The user interface may be optimized to reduce power consumption. For example, if multiple LEDs of one color are used for a particular prompt or indication, the number of LEDs of that color may be reduced. In some embodiments, the output of the LEDs is reduced. In some embodiments, the injection reminder function, e.g., the reminder alarm, is removed. In some embodiments, the downtime indication (e.g., a visual or audio indicator of the amount of time the drug delivery device should be held in place after an injection) is removed. In some embodiments, the end of life pattern is removed (e.g., an indicator that the dose measurement system and / or the drug delivery device has reached the end of its operational life). In some embodiments, the user interface is omitted.

[0251] In some embodiments, the BLE (Bluetooth Low Energy) advertising duration is reduced. The advertising time defines the length of time that the drug delivery device attempts to connect to a mobile phone or other device. This parameter is important when the mobile phone is frequently unreachable (e.g., too far away or switched off). Experiments have shown that 5 seconds is sufficient when the mobile phone is within a properly reachable radio range. Thus, the advertising time can be reduced from 15 seconds to about 5 seconds. This means that the advertising energy can be improved by a factor of 3.

[0252] In some embodiments, the timeout for BLE communication is reduced. Currently the communication channel remains open for 3 seconds after data transfer. This can be improved when the mobile phone or other device sends an explicit communication close command to the medication delivery device and the timeout is simply left as a fallback.

[0253] In some embodiments, the number of communication attempts per day is reduced. After an injection, data can be transferred to a mobile phone, but only if a predetermined period (e.g., 12 hours) has passed since the last data transfer. In some embodiments, priming log data is never transferred separately. This helps users with multiple injections and / or priming doses per day to conserve energy.

[0254] There may be use cases where the user wants to force an immediate data transfer. This can be initiated by a button press pattern. Another step is to only transmit after a specific button press pattern (e.g., pressing the actuator or another button five times in quick succession, or pressing a button a specific number of times longer). In some embodiments, data is transmitted after a normal button release event, but only if a predetermined period of time (e.g., 12 hours) has passed since the last data transfer. In some embodiments, priming log data is not transmitted separately. For example, if the user performs a priming operation where one or two increments of rotation are detected by the processor, this is not transmitted separately from the drug delivery data (in some embodiments, priming, e.g., measurements equal to two or fewer increments of rotation, are ignored and not transmitted).

[0255] It is advantageous to prevent or reduce current peaks since they reduce the usable capacity of the battery. It is therefore advantageous to optimize energy management for UI, sensor and communication current peaks. In some embodiments, the current peaks of electronic components are aligned in sequence. In some embodiments, high current components are not activated simultaneously with high peak current components, or at least such coincidence is minimized.

[0256] Visible LEDs can have high peak currents, but the timing is controllable. BLE communications can have high peak currents, which are neither controllable nor predictable. Thus, in some embodiments, communications begin only after potential user feedback by the LEDs is complete.

[0257] The wireless range may vary depending on the transmit power of the dosage measurement system (e.g., a system-on-chip SoC component). Reducing the power will result in a reduction in the average and peak current. In some embodiments, the maximum output power is +0 dBm with a peak current of 5.3 mA. If the maximum output power is instead +4 dBm, the peak current is 7.5 mA, which may be too high for smaller battery types. Reducing the output power to -4 dBm results in a peak current of 4.2 mA.

[0258] In some embodiments, the battery is a CR1225 coin cell with a nominal capacity of 48 mAh.

[0259] It should be noted that although the above embodiments are described with respect to collecting data from an insulin injection pen, embodiments of the present invention can be used for other purposes, such as monitoring the injection of other medications.

[0260] The injection device may include a cartridge containing a liquid drug or medicament, a portion of which may be expelled from the cartridge according to a dial setting or a preset amount, for example by pressing an injection button. The terms "drug" and "medicament" may refer to a pharmaceutical formulation comprising at least one pharma- ceutical active compound. Further details regarding certain pharmaceutical formulations may be obtained from the disclosure of co-pending application (PCT / EP2018 / 082640, attorney docket no. DE2017 / 081), which is hereby incorporated by reference.

[0261] Those skilled in the art will understand that modifications (addition and / or removal) of the various components of the materials, formulations, devices, methods, systems, and embodiments described herein may be made without departing from the full scope and spirit of the invention, and that the invention encompasses such modifications and all equivalents thereof.

Claims

1. A drug delivery device (100) comprising: a reservoir for the drug; a dispensing mechanism (104) operable to dispense a medicament from the reservoir, the dispensing mechanism (104) including a sleeve (106, 107, 206, 306, 406) configured to rotate during dispensing of the medicament, the dispensing mechanism (104) having a plurality of features (112, 212, 312, 412) at an end of the sleeve (106, 107, 206, 306, 406); a dose measurement system (101, 201, 301, 401) including at least one mechanically actuated sensor (114, 214A, 214C, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D) configured such that, in use, rotation of the sleeve (106, 107, 206, 306, 406) causes the continuous feature (112, 212, 312, 412) to engage the sensor, thereby causing the sensor to detect rotation of the sleeve, and a processor (115) configured to determine a dose dispensed from the medicament reservoir based on the detected rotation of the sleeve; Including, wherein the medication delivery device (100) further comprises a dose dial (108) and a housing (102), the dose dial configured to rotate relative to the housing to set a dose of medication delivered by the dispensing mechanism (104); wherein the drug delivery device (100) further comprises a one-way mechanism, and the sensor (114, 214A, 214C, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D) is attached to the dose dial (108) via the one-way mechanism, whereby the sensor is prevented from rotating relative to the dose dial (108) in the direction that the sleeve (106, 107, 206, 306, 406) rotates during drug dispensing, and is allowed to rotate relative to the dose dial (108) in the opposite direction to that in which the sleeve rotates during drug dispensing.

2. The medication delivery device of claim 1 , wherein the plurality of features comprises a plurality of teeth.

3. The shaped portion (112, 212, 312, 412) is a sleeve (106, 107, 206, The drug delivery device (100) of claim 1 or 2, wherein the proximal end of the drug delivery device (306, 406) is formed.

4. The drug delivery device (100) of any one of claims 1 to 3, wherein the sleeve (106, 107, 206, 306, 406) is a dial sleeve (106, 206, 306, 406) or a drive sleeve (107).

5. 5. The medication delivery device of claim 1, wherein the sensor comprises a sensing member configured to move from an inactivated state to an activated state when engaged by one of the features during rotation of the sleeve, and the sensor detects movement of the sensing member between the inactivated and activated states.

6. 6. The drug delivery device of claim 5, wherein each profile includes a leading edge, and wherein during rotation of the sleeve, a period from engagement of the sensor with a leading edge of a first one of the profiles to engagement of the sensor with a leading edge of an adjacent second one of the profiles represents one coding cycle, and the sensor is activated for 40-60% of the coding cycle, and preferably the sensor is activated for approximately 50% of the coding cycle.

7. 7. The drug delivery device (100) of any one of claims 1 to 6, comprising a torque limiter, wherein the sensor (114, 214A, 214C, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D) is attached to the dose dial (108) via the torque limiter, whereby rotation of the dose dial (108) relative to the housing (102) with a torque greater than a predetermined limit moves the torque limiter to an open state, thereby allowing the dose dial (108) to rotate relative to the sensor, preferably the torque limiter comprising an overload clutch.

8. A dose measuring system (101, 201, 301, 401, 501) for a drug delivery device (100), comprising: a housing (102) containing a reservoir for the drug; a dispensing mechanism (104) operable to dispense a medicament from a reservoir, the dispensing mechanism (104) including a component configured to rotate during dispensing of the medicament and including a plurality of features (112, 212, 312, 412, 512); an actuator (108) configured to be movable relative to the housing (102) when actuated to operate the dispensing mechanism (104) to dispense the medicament from the reservoir; The dose measurement system (101, 201, 301, 401, 501) comprises: a sensor (114, 214A, 214C, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514) movable from an idle position to a detection position, where rotation of the component causes the continuous feature (112, 212, 312, 412, 512) to be detected by the sensor, thereby causing the sensor to detect rotation of the component; a processor (115) configured to determine a dose dispensed from the drug reservoir based on the detected rotation of the component; When the actuator (108) is actuated, the dose measuring system (101, 201, 30 and an activation switch (119, 332, 432) that can move from an initial off state to an on state to activate a sensor (114, 214A, 214C, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514) configured to be attached to an actuator (108) such that upon actuation of the actuator (108), the sensor is moved relative to the housing (102) to reach a detection position, and the activation switch (119, 332, 432) reaches an on state before the sensor reaches the detection position. The dosage measuring system comprising:

9. 9. The dosage measuring system (101, 201, 301, 401, 501) of claim 8, wherein the actuator (108) is slidable relative to the housing (102).

10. 10. The dose measuring system (101, 201, 301, 401, 501) of claim 8 or 9, wherein the activation switch (119, 332, 432) comprises a pivot member (120) that pivots from an off state to an on state to activate the dose measuring system.

11. A dosage measuring system (101, 201, 301, 401, 501) as described in any one of claims 8 to 10, wherein the drug delivery device (100) includes a stopper (122) and the activation switch (119, 332, 432) is configured to abut against the stopper (122) when the activation switch (119, 332, 432) is in an off state.

12. A dosage measuring system (101, 201, 301, 401, 501) as described in any one of claims 8 to 11, wherein when the actuator (108) is moved to operate the dispensing mechanism (104), thereby biasing the activation switch (119, 332, 432) to an on state, the activation switch (119, 332, 432) is configured to engage a portion of the medication delivery device (100), preferably the portion including a portion of the dispensing mechanism (104).

13. A dosage measuring system (101, 201, 301, 401, 501) as claimed in any one of claims 8 to 12, wherein the activation switch (119, 332, 432) is configured to move a first distance from an off state to an on state and the sensor (114, 214A, 214C, 314A, 314B, 314C, 314D, 414A, 414B, 414C, 414D, 514) is configured to move a second distance from an idle position to a detection position, the second distance being greater than the first distance.

14. A dosage measuring system (101, 201, 301, 401, 501) according to any one of claims 8 to 13, comprising first and second radial bearings (125, 126), wherein the actuator (108) is rotatably mounted to a portion of the device via the first and second bearings (125, 126), and the first and second bearings (125, 126) are axially spaced apart.

15. A dosage measuring system (101, 201, 301, 401, 501) according to any one of claims 8 to 14, comprising a support member (121) and a connecting member (127), wherein the actuator (108) is fixed relative to the support member (121) and the support member (121) is connected to the connecting member (127).

16. A dosage measuring system (101, 201, 301, 401, 501) according to any one of claims 8 to 15, comprising any of the configurations of the dosage measuring system (101, 201, 301, 401) of the drug delivery device (100) according to any one of claims 1 to 7.

17. A dosage measuring system (201, 301, 401) for a medication delivery device (100), the medication delivery device comprising a reservoir for a medication and a dispensing mechanism (104) operable to dispense the medication from the reservoir, the dispensing mechanism (104) comprising a component configured to rotate during dispensing of the medication and including a plurality of first and second encoder regions (223, 323, 423, 224, 324, 424), the dosage measuring system comprising: a first and second sensor (214A, 314A, 414A, 214C, 314C, 414C) such that, in use, rotation of the components causes one of the first encoder regions (223, 323, 423) to be aligned with the first sensor (214A, 314A, 414A) while one of the second encoder regions (224, 324, 424) to be aligned with the second sensor (214C, 314C, 414C), and then the second encoder region (224, a first and second sensor configured to distinguish between the first and second encoder regions and detect rotation of the component; and a first and second sensor configured to offset one of the first encoder regions (223, 323, 423) such that one of the first encoder regions (223, 323, 423) is aligned with the first sensor (214A, 314A, 414A) while one of the first encoder regions (223, 323, 423) is aligned with the second sensor (214C, 314C, 414C); a processor (115) configured to determine a dose dispensed from the drug reservoir based on the detected rotation of the component; The dosage measuring system comprising:

18. 18. A dosage measuring system (201, 301, 401) as described in claim 17, wherein the component includes a plurality of shaped portions (212, 312, 412), each first encoding region (223, 323, 423) including at least a portion of a respective shaped portion detectable by the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C) when the component rotates, and the second encoding regions (224, 324, 424) are provided between adjacent first encoding regions (223, 323, 423).

19. 20. The dosage measuring system (201, 301, 401) of claim 18, wherein each shape (212, 312, 412) includes teeth, each first coding region (223, 323, 423) includes at least a portion of a respective tooth detectable by the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C) when the components rotate, and each second coding region (224, 324, 424) includes at least one gap between adjacent teeth.

20. A dosage measuring system (201, 301, 401) according to any one of claims 17 to 19, wherein the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C) are arranged such that for all rotational positions of the component in which the first sensor (214A, 314A, 414A) is aligned with one of the first coding areas (223, 323, 423), the second sensor (214C, 314C, 414C) is aligned with one of the second coding areas (224, 324, 424).

21. 21. A dosage measuring system (201, 301, 401) as claimed in any one of claims 17 to 20, wherein the component comprises a plurality of coding periods (225, 325, 425), each coding period comprising one of a first coding area (223, 323, 423) and an adjacent second coding area (224, 324, 424), and wherein for a given rotational position of the component, the first sensor (214A, 314A, 414A) is aligned with a portion of one of the coding periods and the second sensor (214C, 314C, 414C) is aligned with a different portion of one of the coding periods.

22. a third sensor (414B) configured to detect when the component is in said given rotational position; 22. The dosage measuring system (401) of claim 21, wherein the third sensor is aligned to a different portion of one of the coding periods (225, 325, 425) relative to the first and second sensors (414A, 414C).

23. 23. The dosage measuring system (401) of claim 22, further comprising a fourth sensor (414D), the fourth sensor being aligned with a different portion of one of the coding periods (225, 325, 425) relative to the first, second and third sensors (414A, 414C, 414B) when the component is in the given rotational position.

24. A dosage measuring system (301) as described in any one of claims 17 to 21, further comprising a third sensor (314B), the third sensor (314B) being configured such that when the components rotate in use, the third sensor (314B) is aligned with one of the first coding areas (223, 323, 423) at the same time that the first sensor (314A) is aligned with one of the first coding areas (223, 323, 423).

25. 25. The dosage measuring system (301) of claim 24, further comprising a fourth sensor (314D), the fourth sensor (314D) being configured such that when the components rotate in use, the fourth sensor (314D) is aligned with one of the first coding regions (223, 323, 423) at the same time that the second sensor (314C) is aligned with one of the first coding regions (223, 323, 423).

26. A dosage measuring system (201, 301, 401) according to any one of claims 17 to 25, wherein each of the first and second coding regions (223, 323, 423, 224, 324, 424) extends over the same predetermined angle about the axis of rotation of the component.

27. A dosage measuring system (201, 301, 401) as described in claim 26, wherein the second sensor (214C, 314C, 414C) is offset from the first sensor (214A, 314A, 414A) in a first direction about the axis of rotation by an odd integer multiple of the angle subtended by each first coding region (223, 323, 423, 224, 324, 424) about the axis of rotation.

28. A dosage measurement system (201, 301, 401) as described in any one of claims 17 to 27, wherein the processor (115) is configured to determine the dosage dispensed from the drug reservoir by a process including counting the number of transitions between the first and second coding regions (223, 323, 423, 224, 324, 424) detected by the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C).

29. 29. The dosage measurement system (201, 301, 401) of any one of claims 17 to 28, wherein the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C) are configured to move from an idle position to a detection position, and movement of the sensors to the detection position aligns one of the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C) with one of the first coding regions (223, 323, 423, 224, 324, 424), and the processor (115) is configured to compensate for said alignment when the sensors are moved to the detection position when determining the administered dose.

30. The processor (115) receives a signal from one of the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C) and a signal from the other of the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C).

30. The dose measuring system (201, 301, 401) according to any one of claims 17 to 29, configured to determine the dose dispensed from the drug reservoir based on a signal from the sensor and a counter signal from the sensor.

31. The dosage measurement system (201, 301, 401) of claim 30, wherein the processor (115) is configured to determine the dosage dispensed from the drug reservoir based on a superposition of a signal from one of the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C) and an inverse signal from the other of the first and second sensors (214A, 314A, 414A, 214C, 314C, 414C).

32. The dosage measurement system (201, 301, 401) of claim 31, wherein the processor (115) is configured to determine the dosage dispensed from the drug reservoir by comparing the overlap with a first threshold and a second threshold higher than the first threshold, preferably by counting the number of times the overlap transitions from a value lower than the first threshold to a value higher than the second threshold and / or the number of times the overlap transitions from a value higher than the second threshold to a value lower than the first threshold.

33. A dosage measuring system (201, 301, 401) according to any one of claims 17 to 32, comprising any of the features according to any one of claims 8 to 16.

34. A dosage measuring system (101, 201, 301, 401) according to any one of claims 1 to 7, comprising a dosage measuring system (101, 201, 301, 401, 501) comprising any of the configurations according to any one of claims 8 to 33.

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