Dose measurement system

Abstract

To provide a drug delivery device determining a dose of a prescribed medicine.SOLUTION: A drug delivery device includes a drug reservoir and a medication mechanism. The medication mechanism includes a dosing member movable in an axial direction so as to administer a drug from the drug reservoir. The dose measurement system includes a sensor unit and a processor. The sensor unit is configured to measure axial direction displacement of the dosing member. The processor is configured to determine a dose administered by the drug reservoir on the basis of the measured axial direction displacement of the dosing member.SELECTED DRAWING: Figure 11B

Description

Technical Field

[0001] The present invention relates to a dosage measurement system. The present invention also relates to a dosage measurement device, a drug delivery system, and a method for determining the dosage of a drug administered from a drug delivery device.

Background Art

[0002] There are various diseases that require regular treatment by injection of a drug. Such injections can be performed using an injection device applied by a medical practitioner or the patient himself / herself. As an example, type 1 and type 2 diabetes can be treated by the patient himself / herself, for example, by injecting insulin doses once or several times a day. For example, a pre-filled disposable insulin pen can be used as an injection device. Alternatively, a reusable pen can also be used. With a reusable pen, it is possible to replace an empty drug cartridge with a new one. A set of one-way needles is attached to any pen, and these needles are replaced each time before use. Then, for example, by turning a dosage knob and observing the actual dosage from a dosage window or display of the insulin pen, the insulin dosage to be injected can be manually selected with the insulin pen. Then, the needle is inserted into a suitable skin portion, and the dosage is injected by pressing an injection button of the insulin pen. It is desirable to measure information related to the state and / or use of the injection device, such as information on the injected insulin dosage, so as to be able to monitor insulin injections, for example, to prevent incorrect handling of the insulin pen or to track the dosage already administered.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to provide an improved dosage measurement system, a dosage measurement device, a drug delivery system, and a method for determining the dosage of a drug administered from a drug delivery device.

Means for Solving the Problem

[0004] According to the present invention, there is provided a dosage measurement system for a drug delivery device, the drug delivery device including a drug reservoir and a dosing mechanism including a dosing member axially movable to dispense the drug from the drug reservoir, the dosage measurement system comprising: a sensor unit configured to measure the axial displacement of the dosing member; and a processor configured to determine the dosage dispensed from the drug reservoir based on the measured axial displacement of the dosing member.

[0005] In some embodiments, the sensor unit can be attached to the end of an existing drug delivery device without requiring significant modification of the drug delivery device. For example, if an existing drug delivery device has a dosing member including a male thread, the sensor unit can be attached, for example, to the proximal end of the drug delivery device to measure the axial displacement of the male thread.

[0006] The sensor unit can be configured such that the dosing member moves away from the sensor unit to be positioned to dispense the drug from the drug reservoir.

[0007] In one embodiment, the sensor unit is configured to transmit a signal such that the signal is reflected from the dosing member, and the sensor unit is configured to detect the reflected signal. In one embodiment, the sensor unit is configured such that the signal is reflected from the proximal-facing surface of the male thread. configured.

[0008] In one embodiment, the sensor unit includes a transmission member through which the signal is transmitted. Thus, the transmission member serves to direct the signal towards the dosing member. Thus, the sensor itself does not need to be positioned close to the dosing member. The transmission member can include an optical guide.

[0009] In one embodiment, the dosing member includes a lead screw, and the dosing mechanism further includes a drive member configured to rotate to axially displace the lead screw relative to the drive member to dispense the drug from the drug reservoir. Thus, the sensor can be provided in axial alignment with the lead screw so as to reduce the radial dimension of the drug delivery device.

[0010] In one embodiment, the sensor unit is configured to transmit a signal that moves within the drive member. The drive member can be a drive sleeve. The drive sleeve can include a generally cylindrical peripheral wall.

[0011] The dosing member can be an axially movable component relative to the housing so as to dispense the drug from the drug reservoir.

[0012] In one embodiment, the sensor unit is integrated with the drug delivery device.

[0013] In one embodiment, the sensor unit is removably attachable to the drug delivery device. Thus, the drug delivery device can be disposed of, and the sensor unit can be removed from the drug delivery device for reuse before disposing of the drug delivery device.

[0014] In one embodiment, the sensor unit includes at least one of an optical sensor, a magnetic sensor, an acoustic sensor, or a capacitive sensor.

[0015] In one embodiment, the sensor unit is configured such that the signal is reflected from an end of the dosing member. The sensor unit can be configured such that the signal is reflected from a proximal-facing surface of the dosing member. Thus, the sensor unit can be positioned proximal to the dosing member to reduce the radial dimension of the device.

[0016] In one embodiment, the dosing measurement system includes a display. The display can be configured to display dosing information.

[0017] In one embodiment, the drug delivery device includes an actuator operable by a user to dispense a drug, and the sensor unit is configured to be attached to the actuator. The actuator can include a space, and the sensor unit is configured to be at least partially received within the space.

[0018] In one embodiment, the actuator is configured to move from a first position to a second position when actuated, and the sensor unit is configured to be attached to the actuator so as to move with the actuator between the first and second positions. In one such embodiment, the processor is configured to determine the dose dispensed from the drug reservoir only when the actuator is in the second position.

[0019] In one embodiment, the dose measurement system is configured such that the processor determines the dose dispensed from the drug reservoir only when the actuator is actuated. This helps prevent the processor from providing inaccurate dose information.

[0020] In one embodiment, the dose measurement system includes a first member configured to be fixed to the drug delivery device and a second member removably attachable to the first member. The second member can include a processor. Thus, the first member can be disposed of together with the drug delivery device, and the second member can be attached to the first member of a further drug delivery device for reuse. In one embodiment, the first member includes a transmission member.

[0021] According to the present invention, there is also provided a dose measurement device including the dose measurement system according to the present invention.

[0022] According to the present invention, there is also provided a drug delivery system, the drug delivery system comprising: a drug delivery device including a drug reservoir and a dosing mechanism including a dosing member axially movable to dispense a drug from the drug reservoir; and a dosing measurement system according to the present invention. The drug reservoir can contain a drug.

[0023] According to the present invention, there is also provided a method for determining the dosage of a drug dispensed from a drug delivery device, the drug delivery device including a drug reservoir and a dosing member axially movable to dispense a drug from the drug reservoir, the method comprising: measuring the axial displacement of the dosing member; and determining the dosage dispensed from the drug reservoir based on the measured axial displacement of the dosing member.

[0024] In one embodiment, the dosing member includes a lead screw, and the dosing mechanism further includes a drive member configured to rotate to axially displace the lead screw relative to the drive member to dispense a drug from the drug reservoir. In one embodiment, the sensor unit is configured to be positioned such that the dosing member moves away from the sensor unit to dispense a drug from the drug reservoir. This arrangement enables the drug delivery device to be made thinner.

[0025] The above and other aspects of the present invention will be apparent from, and elucidated with reference to, the embodiments described hereinafter.

[0026] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

Brief Description of the Drawings

[0027]

Figure 1

Figure 2

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Figure 6A

Figure 6B

Figure 7

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 10

Figure 11A

Figure 11B

Figure 12A

Figure 12B

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Figure 17

Figure 18

Mode for Carrying Out the Invention

[0028] The drug delivery devices described herein can be configured to inject a drug into a patient. For example, delivery can be subcutaneous, intramuscular, or intravenous. Such devices can be operated by a patient or a healthcare provider such as a nurse or doctor and can include various types of safety syringes, pen injectors, or auto-injectors. The device can include a cartridge-based system that requires piercing a sealed ampule prior to use. The volume of the drug delivered by these various devices can range from about 0.5 ml to about 2 ml. Yet another device can include a large volume device ("LVD") or a patch pump and is configured to adhere to the patient's skin over a period of time (e.g., about 5, 15, 30, 60, or 120 minutes) to deliver a "large" volume of drug (typically about 2 ml to about 10 ml).

[0029] In combination with a specific agent, the devices described herein can also be customized to operate within the required specification ranges. For example, the device can be customized to inject the agent within a range of specific periods (e.g., about 3 to about 20 seconds for an autoinjector, about 10 minutes to about 60 minutes for an LVD). Other specifications can include low or minimal discomfort, or specific conditions related to human factors, shelf life, expiration date, biocompatibility, environmental considerations, etc. Such variations can occur due to various factors such as the drug viscosity ranging from about 3 cP to about 50 cP. Thus, drug delivery devices often include a hollow needle in the range of about 25 to about 31 gauge. Common sizes are 17 and 29 gauge.

[0030] The delivery devices described herein can also include one or more automated functions. For example, one or more of needle insertion, drug injection, and needle retraction can be automated. The energy for one or more of the automated processes can be provided by one or more energy sources. The energy sources can include, for example, mechanical, pneumatic, chemical, or electrical energy. For example, a mechanical energy source can include a spring, lever, elastomer, or other mechanical mechanism for storing or releasing energy. One or more energy sources can be combined within a single device. The device can further include gears, valves, or other mechanisms for converting the energy into movement of one or more components of the device.

[0031] Each of the one or more automated functions of an autoinjector can be activated via an activation mechanism It is possible. Such an activation mechanism can include one or more of an actuator, such as a button, a lever, a needle sleeve, or other activation components. The activation of an automatic function can be a process including one step or multiple steps. That is, the user needs to activate one or more activation components so that the automatic function is performed. For example, in a process including one step, the user can press the needle sleeve against his or her body and push it down to inject the drug. Other devices require the activation of an automatic function including multiple steps. For example, the user needs to press a button to retract the needle shield to perform an injection.

[0032] In addition, the activation of one automatic function can activate one or more next automatic functions, thereby forming an activation sequence. For example, by activating the first automatic function, at least two of needle insertion, drug injection, and needle retraction can be activated. Some devices also require a specific series of steps so that one or more automatic functions are performed. Other devices can operate by a series of independent steps.

[0033] Some delivery devices can include one or more functions of a safety syringe, a pen injector, or an auto-injector. For example, the delivery device can include a mechanical energy source (typically found in an auto-injector) configured to automatically inject a drug and a dose setting mechanism (typically found in a pen injector).

[0034] The term "distal" refers to a position relatively close to the injection site, and the term "proximal" refers to a position relatively far from the injection site.

[0035] FIG. 1 is an exploded view of the components of a first embodiment of a drug delivery system including a drug delivery device 1 and a dosage measurement system 60.

[0036] In this embodiment, the drug delivery device 1 is in the form of an injection device 1. The injection device 1 includes a dose dial 2 in the form of a dial grip 2, a body or housing 3 having an elongated window 7, and a dose scale drum in the form of a digital sleeve 4.

[0037] The digital sleeve 4 has an outer thread 5 on its outer peripheral surface that extends in a helical pattern from the distal end to the proximal end. The digital sleeve 4 holds a mark 6 printed on the digital sleeve. The mark 6 is located on the digital sleeve 4 in a helical pattern.

[0038] The injection device 1 further includes a sliding element 11 configured as a gauge component having a sliding window 12.

[0039] The injection device 1 further includes a dosing mechanism, which includes a drive spring 14 in the form of a torsion spring 14, a trigger button 18, a clutch plate 19, a last dose nut 20, a drive sleeve 21, a clutch spring 22, a dosing member in the form of a lead screw 23, and a support portion 24 provided at the distal end of the lead screw 23.

[0040] A cartridge holder 25 that can be attached to the distal end of the housing 3 is provided. The cartridge holder 25 receives a cartridge 26 filled with a drug, and a stopper (not shown) is located in the cartridge 26. When the support portion 24 moves in the distal direction, the support portion 24 displaces the stopper, and thus, when a dosing interface such as a double-headed needle cannula is attached to the distal end of the cartridge 26, the drug is dispensed from the cartridge 26.

[0041] The digital sleeve 4 includes an upper digital sleeve member 27 called the upper part of the digital sleeve 27 and a lower digital sleeve member 28 called the lower part of the digital sleeve 28. The dose dial 2 and the button 18 are separate individual components. In this embodiment, all components are positioned concentrically around a common major longitudinal axis of the mechanism. The body or housing 3 can also be a body element fixed to the outer housing or casing.

[0042] The button 18 is permanently splined to the dose dial 2. The button 18 is also splined to the upper part of the digital sleeve 27 when the button 18 is not depressed, but this spline interface is disengaged when the button 18 is depressed. When the button 18 is depressed, the spline on the button 18 engages the spline on the housing 3, preventing rotation of the button 18 (and thus the dose dial 2) during dosing. These splines are disengaged when the button 18 is released, allowing the dose to be dialed.

[0043] The dose dial 2 is axially constrained to the housing 3. The dose dial 2 is non-rotatably constrained to the button 18 via a splined connection interface. The lower part of the digital sleeve 28 is firmly fixed to the upper part of the digital sleeve 27 during assembly to form the digital sleeve 4 and is a separate component to simplify the molding tooling and assembly of the digital sleeve 4. This subassembly is constrained to the housing 3 by holding an element (not shown) towards the distal end so as to allow rotation rather than translational movement. The lower part of the digital sleeve 28 is marked with a series of numerical indicators, and these indicators are visible through the window 12 of the sliding element 11 and the window 7 in the housing 3 for indicating the dose of the dialed drug.

[0044] The clutch plate 19 is splined to the digital sleeve 4. The clutch plate 19 is also connected to the drive sleeve 21 via a ratchet interface. The ratchet provides a detent position corresponding to each dosage unit between the digital sleeve 4 and the drive sleeve 21 and engages different tooth rake angles during clockwise and counterclockwise relative rotation. The sliding element 11 is constrained to prevent rotation relative to the housing 3 via a splined connection interface but allows translational movement. The sliding element 11 has on its inner surface a helical function that engages the helical outer thread 5 cut into the digital sleeve 4, so that when the digital sleeve 4 rotates, the sliding element 11 moves axially in a translational motion. This helical function on the sliding element 11 also creates a stop abutment against the ends of the helix cut into the digital sleeve 4 to limit the minimum and maximum dosages that can be set.

[0045] The final dosage nut 20 is positioned between the digital sleeve 4 and the drive sleeve 21. The final dosage nut 20 is non-rotatably constrained to the digital sleeve 4 via a splined connection interface. The final dosage nut 20 moves along a helical path relative to the drive sleeve 21 via a screw interface when relative rotation occurs between the digital sleeve 4 and the drive sleeve 21. The drive sleeve 21 extends from the interface with the clutch plate 19 to the contact point with the clutch spring 22. During dial setting, the splined connection tooth interface with the digital sleeve 4 is not engaged, but when the button 18 is pressed, it engages to prevent relative rotation between the drive sleeve 21 and the digital sleeve 4 during dosing.

[0046] A further spline connection tooth interface with the housing 3 prevents rotation of the drive sleeve 21 during dose setting. When the button 18 is pressed, the drive sleeve 21 and the housing 3 are disengaged and the drive sleeve 21 can rotate. During dose setting, by the action of the user rotating the dose dial 2, force is applied to the helical drive spring 14 and energy is stored. The spring energy is stored until the dosing of the mechanism is triggered, and when the dosing of the mechanism is triggered, the stored energy is used to deliver the drug from the cartridge to the user. One end of the drive spring 14 is attached to the housing 3 and the other end is attached to the digit sleeve 4. The drive spring 14 is pre-wound when assembled and thus applies torque to the digit sleeve 4 when the mechanism is dialed to the zero unit. By the action of rotating the dose dial 2 to set the dose, the digit sleeve 4 rotates relative to the housing 3 and further force is applied to the drive spring 14.

[0047] The lead screw 23 is non-rotatably constrained to the drive sleeve 21 via a spline connection interface. When rotated, the lead screw 23 is axially moved relative to the drive sleeve 21 by a screw interface (not shown) with the housing 3. The support 24 is axially constrained to the lead screw 23 and acts on the stopper in the liquid drug cartridge 26.

[0048] The axial positions of the drive sleeve 21, the clutch plate 19, and the button 18 are defined by the action of a clutch spring 22 that applies a proximal force to the drive sleeve 21. This spring force is reacted through the drive sleeve 21, the clutch plate 19, and the button 18, and when "at rest", is further reacted through the dose dial 2 to the housing 3. This spring force ensures that the ratchet interface is always engaged. In the "at rest" position, it is also ensured that the button spline engages the number sleeve 4 and the teeth of the drive sleeve engage the housing 3. The housing 3 provides positions for the liquid pharmaceutical cartridge 26 and cartridge holder 25, windows for viewing the dose number and sliding element, and functions on its outer surface for axially holding the dose dial 2 (not shown). A removable cap fits over the cartridge holder 25 and is held via a clip function on the housing 3.

[0049] Figure 2 shows the inside of the sliding element 11 having a window 12 and a male screw function 29 on the inner surface of the sliding element 11, and the male screw function 29 engages the outer thread 5 (see Figure 3) of the number sleeve 4. The screw function 29 has a zero dose abutment 30 and a maximum dose abutment 31. As shown in Figure 3, the outer thread 5 has a zero dose abutment 32 at one end of the thread 5 and a maximum dose abutment 33 at the other end of the thread 5, and thus any dose size can be incrementally selected between zero and a pre-defined maximum to suit the drug and user profile. A drive spring 14 having a plurality of pre-wound turns applied during assembly of the device applies torque to the number sleeve 4 and is prevented from rotating by the zero dose abutment.

[0050] As shown in FIG. 4, the inner surface of the digital sleeve 4 has a retraction portion 34, followed by a groove 35 and a retention point 36. The automatic assembly of the drive spring 14 onto the digital sleeve can be achieved by incorporating a large retraction portion 34 and a groove function 35. When the drive spring 14 rotates during assembly, the hook end 37 (see FIG. 5) at one end of the drive spring 14 is positioned within the groove function 35 and then engages with the retention point 36 within the digital sleeve 4.

[0051] As shown in FIG. 5, the drive spring 14 is formed from a helical wire having at least two different pitches. Both ends are formed from "closed" coils 38, i.e., the pitch is equal to the wire diameter and each coil contacts the adjacent coil. The central portion has "open" coils 39, i.e., the coils do not contact each other. Following assembly, compression of the drive spring 14 axially biases the digital sleeve 4 relative to the housing 3 in a consistent direction, reducing the influence of geometric tolerances.

[0052] To select the dosage, the user rotates the dial grip 2 clockwise. As shown in FIGS. 6A and 6B, the button 18 has an inner spline 40, and the inner spline 40 engages with the corresponding spline 41 at the top of the digital sleeve 4 to create a spline connection interface 40 / 41. The dial grip 2 is spline-connected to the button 18, and the button 18 has a further set of splines 42 for engaging with the corresponding splines of the housing 3. During dosage selection, the rotation of the dial grip 2 is transmitted to the button 18. The button 18 is spline-connected to the upper part 27 of the digital sleeve (only during dosage selection) via the spline 40. The upper part 27 of the digital sleeve is permanently fixed to the lower part 28 of the digital sleeve to form the digital sleeve 4. Thus, when the dial grip 2 rotates, the same rotation is generated in the digital sleeve 4. When the digital sleeve 4 rotates, a force is applied to the drive spring 14, increasing the energy stored by the drive spring 14. When the digital sleeve 4 rotates, the sliding element 11 translates axially by its screw engagement with the digital sleeve 4, thereby indicating the value of the dosage set by the dial. ​

[0053] As shown in FIG. 7, the drive sleeve 21 has a spline 43, and the spline 43 engages with a corresponding spline 44 formed inside the housing 3 to create a spline connection interface 43 / 44. When the dose is set, the rotation of the drive sleeve 21 is prevented, and the digital sleeve 4 rotates by the engagement of its spline connection teeth 43 with the teeth 44 of the housing 3. Accordingly, relative rotation occurs between the clutch plate 19 driven by the digital sleeve 4 and the drive sleeve 21 via a ratchet interface.

[0054] As shown in FIGS. 8A and 8B, the end face of the drive sleeve 21 is provided with inclined teeth 45, and the clutch plate 19 is provided with inclined teeth 46. The inclined teeth 45 of the drive sleeve 21 form a ratchet interface 45 / 46 together with the inclined teeth 46 on the clutch plate 19.

[0055] On the outer periphery of the clutch plate 19, spline coupling teeth 47 are formed for engaging with corresponding grooves on the number sleeve 4. The user torque required to rotate the dial grip 2 is the sum of the torque required to wind up the drive spring 14 and the torque required to loosen the ratchet interface 45 / 46. The clutch spring 22 is designed to provide an axial force to the ratchet interface 45 / 46 and bias the clutch plate 19 onto the drive sleeve 21. This axial load acts to maintain the engagement of the ratchet teeth 45, 46 of the clutch plate 19 and the drive sleeve 21. The torque required to loosen the ratchet interface 45 / 46 in the dose setting direction depends on the axial load applied by the clutch spring 22, the clockwise inclination angle of the ratchet, the coefficient of friction between the mating surfaces, and the average radius of the ratchet function. When the user rotates the dial grip 2 sufficiently to increment the mechanism by one increment, the number sleeve 4 rotates by one ratchet tooth relative to the drive sleeve 21. At this point, the ratchet teeth 45, 46 re-engage into the next detent position. This re-engagement of the ratchet generates an audible click and provides tactile feedback by a change in the required torque input.

[0056] When no user torque is applied to the dial grip 2, the number sleeve 4 is prevented from rotating rearward by receiving only the torque applied by the drive spring 14 through the ratchet engagement 45 / 46 between the clutch plate 19 and the drive sleeve 21. The torque required to loosen the ratchet interface 45 / 46 in the counterclockwise direction depends on the axial load applied by the clutch spring 22, the counterclockwise inclination angles of the ratchet teeth 45, 46, the coefficient of friction between the mating surfaces, and the average radius of the ratchet function. The torque required to loosen the ratchet interface 45 / 46 must be greater than the torque applied to the number sleeve 4 (and thus the clutch plate 19) by the drive spring 14. Therefore, the ratchet inclination angle increases in the counterclockwise direction, ensuring that this is the case while ensuring that the dial-up torque is as low as possible. The user can choose to increase the selected dosage by continuously rotating the dial grip 2 in the clockwise direction. The process of loosening the ratchet interface 45 / 46 between the number sleeve 4 and the drive sleeve 21 is repeated for each dosage increment. Additional energy is stored in the drive spring 14 for each dosage increment, and audible and tactile feedback is provided for each increment dialed by re-engagement of the ratchet teeth 45, 46. The torque required to rotate the dial grip 2 increases as the torque required to wind up the drive spring 14 increases. Therefore, the torque required to loosen the ratchet interface 45 / 46 in the counterclockwise direction must be greater than the torque applied to the number sleeve 4 by the drive spring 14 when the maximum dosage is reached.

[0057] If the user continues to increase the selected dosage until the maximum dosage limit is reached, the number sleeve 4 engages the maximum dosage abutment 31 (see FIGS. 2 and 3) on the sliding element 11. This prevents further rotation of the number sleeve 4, the clutch plate 19, and the dial grip 2.

[0058] The final dose nut 20 is splined to the digital sleeve 4 and at the same time screwed to the drive sleeve 21. Thus, due to the relative rotation of the digital sleeve 4 and the drive sleeve 21 during dose setting, the final dose nut 20 moves along its screw path towards the final dose abutment on the drive sleeve 21. Depending on how many increments have already been delivered by the mechanism during dose selection, the final dose nut 20 can contact its final dose abutment with the drive sleeve 21. This abutment prevents further relative rotation between the digital sleeve 4 and the drive sleeve 21 and thus limits the dose that can be selected. The position of the final dose nut 20 is determined by the total number of relative rotations between the digital sleeve 4 and the drive sleeve 21 that occur each time the user sets the dose.

[0059] When the dose is set, the user can deselect any number of increments from this dose. Deselection of the dose is achieved by the user rotating the dial grip 2 counterclockwise. The torque applied by the user to the dial grip 2, in combination with the torque applied by the drive spring 14, is sufficient to loosen the ratchet interface 45 / 46 between the clutch plate 19 and the drive sleeve 21 in the counterclockwise direction. When the ratchet interface 45 / 46 is loosened, a counterclockwise rotation occurs within the digital sleeve 4 (via the clutch plate 19), causing the digital sleeve 4 to return towards the zero dose position and the drive spring 14 to be relaxed. Due to the relative rotation between the digital sleeve 4 and the drive sleeve 21, the final dose nut 20 returns along its helical path away from the final dose abutment.

[0060] As shown in FIGS. 9A and 9B, to ensure that only the set dose number is visible to the user, the sliding element 11 has a flange or extension on both sides of the window area that covers the numbers printed on the digital sleeve 4 adjacent to the dial-selected dose. The injection device 1 includes a visual feedback function in addition to the individual dose number display. The distal end of the sliding element 11 has an extension 15 (see FIG. 1) that creates a sliding scale through the window 48 in the housing 3. The window 48 can be made smaller than the window 7.

[0061] When the dose is set by the user, the sliding element 11 translates axially, and the distance of its movement is proportional to the magnitude of the set dose. This function provides the user with clear feedback regarding the approximate size of the set dose. The dosing speed of the injection device 1 can be faster than that of a manual injection device, and thus it may not be possible to read the numerical dose display during dosing. The sliding element 11 provides the user with feedback regarding the progress of dosing that does not require reading the dose number itself during dosing.

[0062] The window 48 can be formed by exposing a contrast-colored component 49 with an opaque element on the sliding element 11 thereunder. Alternatively, a coarse dose number or other indicator can be printed on the exposed element 49 to provide a more precise resolution. In addition, this display simulates the syringe movement during dose setting and dosing.

[0063] To reduce the ingress of dust and prevent the user from touching the movable members, the observation openings 7 and 48 in the housing 3 are covered by translucent windows. These windows 7, 48 can be separate components, but in this embodiment, they are incorporated into the housing 3 using a "two-shot" molding technique. The first shot of translucent material forms the internal functions and the windows, and then the "second shot" of opaque material forms the outer cover of the housing 3.

[0064] Delivery of the dose is initiated by the user axially depressing button 18. When button 18 (see FIGS. 6A and 6B) is depressed, splines 40 and 41 between button 18 and digital sleeve 4 are disengaged, rotatably disconnecting button 18 and dial grip 2 from the delivery mechanism.

[0065] As shown in FIG. 10, spline 42 on button 18 engages spline 50 on housing 3 to prevent rotation of button 18 (and thus dial grip 2) during dosing. When button 18 is stationary during dosing, button 18 can be used in the dosing clicker mechanism. A stop function within housing 3 limits the axial movement of button 18, reducing the risk of damaging internal components in response to any axial abuse loads applied by the user.

[0066] As shown in FIG. 11A, clutch plate 19 disposed between drive sleeve 21 and button 18 is axially moved by button 18. Further, drive sleeve 21 is axially moved by clutch plate 19. As shown in FIGS. 12A and 12B, due to the axial displacement of drive sleeve 21, spline 51 on drive sleeve 21 engages spline 52 on digital sleeve 4, thus forming a spline coupling tooth interface 51 / 52 and preventing relative rotation between drive sleeve 21 and digital sleeve 4 during dosing.

[0067] The spline coupling tooth interface 43 / 44 (shown in FIG. 7) between drive sleeve 21 and housing 3 is disengaged, and thus drive sleeve 21 can then rotate relative to housing 3 and is driven by drive spring 14 through digital sleeve 4 and clutch plate 19. When drive sleeve 21 rotates, its spline engagement causes parent screw 23 to rotate, and then parent screw 23 advances due to its screw engagement with housing 3. Also, when digital sleeve 4 rotates, sliding element 11 traverses axially rearward to its zero position, thereby stopping the mechanism at the zero dose abutment (shown in FIGS. 2 and 3).

[0068] The drive sleeve 21 or the spline teeth on the housing 3 can be tilted, so that as a result, the zero-dose abutment 30 stops the rotation of the digital sleeve 4, and thus the drive sleeve 21, at the end of the dose. When the button 18 is released, the spline teeth between the drive sleeve 21 and the housing 3 rotate the drive sleeve 21 slightly rearward. As a result, the lead screw 23 moves away from the stopper in the axial rearward direction, and the lower part 28 of the digital sleeve rotates from the zero-dose stop position, which helps to prevent possible smudging.

[0069] In this embodiment, the dosage measurement system 60 is in the form of a dosage measurement device 60 attached to the proximal end of the injection device 1.

[0070] The dosage measurement device 60 includes a housing 61 and a display 62 for presenting dosage information. However, it should be understood that in an alternative embodiment (not shown), the display 62 may be omitted.

[0071] As shown in FIG. 14, the data measurement device 60 also includes one or more processors 63, such as a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., together with one or more computer-readable memory media 64. In this embodiment, the computer-readable memory media 64 includes memory units 64A, 64B including a program memory 64A and a main memory 64B capable of storing software for execution by the processor 63.

[0072] A sensor unit 65 including one or more sensors 66 is provided. The sensor unit 65 is configured to detect the movement of the dosing member of the dosing mechanism. In this example, the dosing member is the lead screw 23. In this particular embodiment, the sensor 66 includes an optical sensor 66. The optical sensor 66 includes a light source 66A such as a laser and a light detector 66B such as a phototransducer.

[0073] The sensor unit 65 further includes an optical guide 67, which will be described in more detail below.

[0074] The dosage measurement device 60 further includes an output 68, a power switch 69, and a battery 70. Actuation of the power switch 69 turns the power of the dosage measurement device 60 on and off.

[0075] In one embodiment, the power switch 69 includes a button 69 on the housing 61 of the dosage measurement device 60 that is actuated by the user. In another embodiment, the power switch 69 is configured to respond to pressure applied to the display 62 by turning the power of the dosage measurement device 60 on or off. In yet another embodiment (not shown), the power switch 69 is actuated when the user actuates button 18. For example, the power switch 69 can include an electrical contact (not shown) on button 18 that makes electrical contact with a second electrical contact (not shown) on a different member of the injection device 1, such as housing 3 or the digital sleeve 4, when button 18 is depressed and the power of the dosage measurement device 60 is turned on. When the first and second electrical contacts make contact, the power circuit can be closed, and thus the power of the dosage measurement device 60 is turned on.

[0076] Advantageously, such an arrangement serves to ensure that the dosage measurement device 60 operates to measure the dosage being delivered only when the button 18 is depressed into the housing 3 and thus in its operating position. This can improve the accuracy of dosage measurement. Because otherwise, when the button 18 moves axially into the housing 3, thereby causing the sensor unit 65 to move towards the lead screw 23, and thus the movement that reduces the distance between the sensor unit 65 and the lead screw 23 (indicated by the arrow "D" in FIGS. 11A and 11B) would appear to the sensor unit 65 as if the drug reservoir were being refilled with drug. Further, when the button 18 is released, the movement of the button 18 moving axially out of the housing 3, thereby causing the sensor unit 65 to move away from the lead screw 23 and thus increasing the distance "D" between the sensor unit 65 and the lead screw 23, would appear to the sensor unit 65 as if the dosage had been discharged from the injection device 1. However, it should be understood that other arrangements are possible that serve to ensure that the dosage measurement device 60 operates to measure the dosage being delivered only when the button 18 is in its operating position. For example, the processor 63 can be configured to start measuring the dosage dispensed from the injection device 1 only after calculating that the sensor unit 65 has moved towards the lead screw 23 by a distance D corresponding to the actuation of the button 18 by the user. Additionally or alternatively, if the processor 63 calculates that the sensor unit 65 has moved a distance D relative to the lead screw 23 within a consistent period following the release of the button 18, the processor 63 may, this The dosage measurement can be ignored, or a flag can be set for this dosage measurement as if the button 18 is released. In a further embodiment, the power switch 69 is arranged such that as a result of pressing the button 18, the power switch 69 is also pressed simultaneously to turn on the power of the dosage measurement device 60, and / or as a result of releasing the button 18, the power switch 69 is also released to turn off the power of the dosage measurement device 60. In another embodiment, instead of the power switch 69 for turning on and off the power of the dosage measurement device, pressing the switch 69 can execute a specific program or routine, for example, causing the processor 63 to execute a dosage determination program.

[0077] In this embodiment, the processor 63, the computer-readable memory medium 64, the sensor 66, the output 68, and the battery 70 are located within the housing 61. However, it should be understood that in an alternative embodiment (not shown), one or more of these components can also be located outside the housing 61.

[0078] The output 68 can be a wireless communication interface for communicating with another device via a wireless network such as wi-fi or Bluetooth (registered trademark), or an interface for a wired communication link such as a socket that receives a Universal Serial Bus (USB), mini-USB, or micro-USB connector.

[0079] Figures 11A and 11B show the proximal ends of the dosage measurement device 60 and the injection device 1.

[0080] Button 18 includes an aperture 71 in its proximal face 18A, and the aperture 71 is configured to receive at least a portion of the dosage measurement device 60 into a space 72 within the button 18. In this embodiment, the clutch plate 19 includes an aperture 73, and at least a portion of the data measurement device 60 extends through the aperture 73 within the clutch plate 19 and is received within the proximal end of the drive sleeve 21. More particularly, the prism 67 extends axially from the housing 61 of the dosage measurement device 60, and thus the prism 67 extends through the space 72 of the button 18 and the aperture 73 of the clutch plate 19. The end 67A of the prism 67 is received within the hollow center of the drive sleeve 21.

[0081] The housing 61 of the dosage measurement device 60 includes one or more attachment formations 74, and the attachment formations 74 are configured to engage corresponding attachment formations 75 on the button 18. In this embodiment, the attachment formations 74 of the dosage measurement device 60 include protrusions 74 that engage respective recesses 75 within the button 18, and thus the dosage measurement device 60 can be clipped to the button 18. However, it should be understood that in alternative embodiments (not shown), the attachment formations 74 are provided on different components of the injection device 1.

[0082] In some embodiments, the engagement of the attachment formations 74, 75 is such that the dosage measurement device 60 cannot rotate relative to the button 18 when the dosage measurement device 60 is attached to the button 18.

[0083] In an embodiment where the dosage measurement device 60 is releasably attachable to the injection device 1, the attachment formations 74, 75 can provide a clip-type arrangement that allows for easy removal of the dosage measurement device 60. Such an arrangement is useful because when the dosage measurement device 60 is used with a disposable injection device 1, it becomes possible to remove the dosage measurement device 60 from the injection device 1 and reuse it. The removable dosage measurement device 60 also provides additional flexibility to the user because the user can freely attach and remove the dosage measurement device 60.

[0084] In some embodiments, the attachment formations 74, 75 can be configured to permanently attach the dosage measurement device 60 to the injection device 1, for example using a "snap fit". Alternatively, the dosage measurement device 60 can be permanently attached in other ways, for example by adhesion. Such a permanent attachment is useful when the injection device 1 is reusable. The number and / or position of the attachment formations 74, 75 can be configured such that the dosage measurement device 60 can be attached to the injection device 1 in only one specific orientation with respect to the injection device 1.

[0085] The light guide 67 is configured such that when the dosage measurement device 60 is attached to the injection device 1, light emitted from the light source 66A is transmitted axially along the length of the light guide 67, then transmitted from the end 67A of the light guide 67 and directed towards the proximal-facing end surface 23A of the male screw 23. The light (indicated by the arrow "L" in FIG. 11B) is reflected from the end surface 23A of the male screw 23 and moves back towards the light guide 67. The light enters the light guide 67 and is transmitted through the light guide 67. Thus, the reflected light reaches the sensor 66 after moving through the light guide 67, and the light is detected by the photodetector 66B.

[0086] Light can generally move axially between the optical guide 67 and the end face 23A of the parent screw 23. In this example, the light is transmitted at an angle with respect to the axis A-A from the optical guide 67. Thus, when the light hits the end face 23A of the parent screw 23, the light is reflected from the end face 23A at an angle X with respect to the central axis A-A. The axis A-A is the central axis A-A of the injection device 1 in this embodiment. However, in an alternative embodiment, it can be an axis parallel to the central axis A-A or can have a different orientation. Then the light moves again towards the optical guide 67 at the said angle X with respect to the central axis A-A, and then after being transmitted axially through the optical guide 67, the light reaches the sensor 66. To facilitate this, the end 67A of the optical guide 67 can include a prism 67A. The prism 67A ensures that the light is transmitted from the optical guide 67 at an angle with respect to the central axis A-A.

[0087] The distance Y between the reflected light beam L and the central axis A-A when the light enters the end 67A of the optical guide 67 depends on the distance D between the end 67A of the optical guide 67 and the end face 23A of the parent screw 23. The optical sensor 66 is configured to detect the distance Y. For example, the photodetector 66B can include an array of photodetection sensors (not shown), and different photodetection sensors in the array detect reflected beams with different values of the distance Y. The array of photodetection sensors can be arranged radially within the array.

[0088] In a particular embodiment, the sensor 66 can be arranged to emit and / or detect only light having a specific frequency or specific polarization characteristics in order to reduce the influence of stray light. The sensor 66 can be configured to emit and / or detect a laser beam.

[0089] During drug delivery, the drive sleeve 21 rotates to rotate the lead screw 23. As a result, the lead screw 23 moves axially in the distal direction relative to the housing 3 by screw engagement with the housing 3 of the injection device 1 or another component. Thus, the end face 23A of the lead screw 23 moves axially away from the sensor unit 65, and thus the distance D between the end face 23A of the lead screw 23 and the sensor unit 65 increases. The increase in the distance D between the sensor unit 65 and the end face 23A of the lead screw 23 causes the distance Y between the central axis A-A and the point where the reflected light beam L enters the optical guide 67 to increase. This increase in the distance Y is detected by the photodetector 66B. Since the sensor unit 65 is connected to the processor 63, the processor 63 can detect the increase in the distance Y and thus determine the amount of pharmaceutical delivered by the injection device.

[0090] When drug delivery is complete, the lead screw 23 stops moving axially relative to the dosage measurement device 60, and as a result, the distance D, and thus the distance Y, remains constant. Thus, the signal from the sensor 66 remains at a substantially constant level.

[0091] In some embodiments, the processor 63 is arranged to monitor the period elapsed since the last change in the output of the sensor 66. When the elapsed period reaches a predetermined threshold, it is considered that drug delivery is complete, and the processor 63 proceeds to determine the dosage of the drug delivered to the user based on the change in the measured distance Y.

[0092] The processor 63 then stores the determined drug dosage in the main memory 64B. The processor 63 can also store timestamp information to provide a log recording the delivery of the drug to the user. The processor 63 can then turn off the power of the dosage measurement device 60 to conserve battery power. Alternatively, the power of the dosage measurement device 60 can be turned off when the user releases the button 18 and / or the button 69, or immediately thereafter.

[0093] When the user activates the power switch 69 and the power of the dosage measurement device 60 is turned on again, the processor 63 can control the display 62 to show the determined drug dosage information to assist the user's memory. Optionally, the processor 63 can monitor the elapsed time since the determined drug dosage was delivered and also control the display to show that elapsed time information. For example, the processor 63 can cause the display 62 to perform a periodic switching between the display of the determined drug dosage information and the display of the elapsed time.

[0094] In some embodiments, the processor 63 is configured to calculate the axial displacement of the lead screw 23 relative to the drive sleeve 21 by calculating the difference between the distance D at the start of drug delivery between the sensor unit 65 and the end face 23A and the distance D at the end of drug delivery. The processor 63 can determine the delivered dosage based on the difference between the distance D at the start of drug delivery and the distance D at the end of drug delivery.

[0095] The processor 63 can also transmit the determined drug dosage to another device such as a computer (not shown), and can also transmit the timestamp information if determined. As described above, the output 68 can be configured to transmit information using a wireless communication link. Alternatively, the dosage measurement device 60 can be connected to a computer (not shown) using a wired connection (not shown) to enable uploading of information to the computer. The processor 63 can be configured to periodically transmit information to the computer. In some embodiments, the display 62 can be omitted. In some embodiments, the dosage measurement system 60 can be used to monitor compliance with a particular dosage regime.

[0096] The specific embodiments described in detail above are only intended as examples of how the present invention can be implemented. Many variations in the configuration of the dosage measurement device 60 and / or the injection device 1 can be considered. For example, in an alternative embodiment (not shown), the sensor 66 instead detects the time delay between the emission of a light pulse by the light source 66A and the reception by the light detector 66B, and determines the distance D between the sensor unit 65 and the end face 23A of the parent screw 23. The greater the distance D, the greater the time delay between the emission of the light pulse by the sensor 66 and the reception of the reflected pulse. Thus, the processor 63 can determine the delivered dosage based on the delay between one or more received light pulses. In some embodiments, it should be understood that the light guide 67 and / or the prism 6 7A can be omitted. In some embodiments, the sensor 66 includes an optical triangulation sensor configured to measure the distance between the sensor and the end face 23A of the parent screw 23, and can include a laser triangulation sensor.

[0097] The dosage measurement system enables the determination of the dosage dispensed from the drug reservoir without measuring the rotation of the components of the dosing mechanism. Thus, the sensor unit need not have a specific rotational direction with respect to the dosing member and need not be fixedly non-rotatable with respect to the dosing member during use.

[0098] Referring next to FIG. 15, a drug delivery system according to a second embodiment of the present invention is shown. The drug delivery system is similar to the measurement delivery system described above with reference to the first embodiment of the present invention, and similar functions retain the same reference numerals. The drug delivery system includes a drug delivery device 1 and a dosage measurement system 80.

[0099] The drug delivery device 1 is in the form of an injection device 1. The dosage measurement system 80 includes a dosage measurement device 80 attached to the proximal end of the injection device 1. The dosage measurement device 80 includes a housing 81, a battery 82, a processor 83, a computer-readable memory medium (not shown), a power switch (not shown), an output (not shown), and a user interface 84.

[0100] The difference between the dosage measurement system 60 of the first embodiment and the dosage measurement system 80 of the second embodiment is that the sensor unit 65 is omitted and replaced by an alternative sensor unit 85. The sensor unit 85 includes a sensor 86. In this embodiment, the sensor 86 is an acoustic sensor 86 having an acoustic source (not shown), such as a speaker, and an acoustic detector (not shown), such as a microphone. In one embodiment, the acoustic sensor 86 is an ultrasonic sensor.

[0101] The sensor unit 85 is arranged such that the acoustic signal emitted by the acoustic sensor 86 moves towards the end face 23A of the parent screw 23, is reflected, and returns towards the acoustic sensor 86, so that the reflected signal is detected by the acoustic sensor 86. The acoustic sensor 86 is connected to the processor 83.

[0102] The processor 83 is configured to determine the dosage administered from the injection device 1 based on the characteristics of the reflected signal detected by the acoustic sensor 86, and the characteristics of the signal depend on the distance D between the sensor unit 85 and the end face 23A of the parent screw 23. For example, the processor 83 can be configured to determine the dosage administered from the injection device 1 based on the detected time delay between the emission of a pulse or time-varying signal by the acoustic sensor 86 and the reception of the reflected signal by the acoustic sensor 86. The greater the distance D between the sensor unit 85 and the end face 23A of the parent screw 23, the greater the time delay between the transmission and reception of the signal. Therefore, the processor 83 can determine the delivered dosage based on the delay between the transmission and reception of one or more signals. Alternatively or in addition, the processor 83 can be configured to determine the dosage administered from the injection device 1 based on the detected attenuation of the reflected signal received by the acoustic sensor 86, which is the difference in amplitude between the transmitted signal and the received signal. The greater the distance D between the sensor unit 85 and the end face 23A of the parent screw 23, the greater the attenuation of the signal.

[0103] The processor 83 can be configured to operate the user interface 84 when the dosage condition is met, for example, when a predetermined dosage of the drug has been delivered by the injection device 1. The user interface 84 can include, for example, a buzzer and / or a light.

[0104] Referring next to FIG. 16, a drug delivery system according to a third embodiment of the present invention is shown. The drug delivery system is similar to the measurement delivery system described above with reference to the first embodiment of the present invention, and similar functions retain the same reference numerals. The drug delivery system includes a drug delivery device 1 and a dosage measurement system 90.

[0105] The drug delivery device 1 is in the form of an injection device 1. The dosage measurement system 90 includes a dosage measurement device 90 attached to the proximal end of the injection device 1. The dosage measurement device 90 includes a housing 91, a processor (not shown), a computer-readable memory medium (not shown), a power switch 99, a battery (not shown), and an output (not shown).

[0106] The difference between the dosage measurement system 60 of the first embodiment and the dosage measurement system 90 of the third embodiment is that the sensor unit 65 is omitted and replaced by an alternative sensor unit 95. The sensor unit 95 includes a sensor 96, and in this embodiment, the sensor 96 is an acoustic sensor 96 having an acoustic source (not shown) and an acoustic detector (not shown). The acoustic sensor 96 is located on a support member 97. In this embodiment, the acoustic sensor 97 includes a piezoelectric acoustic sensor 97 having one or more piezoelectric transducers (not shown) for generating and / or detecting acoustic signals.

[0107] The support member 97 extends from the housing 91, and thus when the dosage measurement device 90 is attached to the injection device 1, the support member 97 extends axially in the distal direction, and thus the end 97A of the support member 97 is located within the drive sleeve 21. The sensor 96 is attached on or near the end 97A, and thus the sensor 96 is directed toward the end face 23A of the parent screw 23. More specifically, the sensor 96 is arranged such that the signal transmitted by the sensor 96 is reflected by the end face 23A and the reflected signal is detected by the sensor 96.

[0108] The sensor 96 is connected to a processor (not shown) by one or more conductive elements 98, such as tracks or wires, extending from the sensor 96 to the housing 91. The conductive element 98 can be adhered to the support member 97 or embedded within the support member 97.

[0109] As described above, a processor (not shown) is configured to determine the dosage administered from the injection device 1 based on the characteristics of the reflected signal detected by the sensor 96, and the characteristics of the signal depend on the distance D between the sensor unit 95 and the end face 23A of the parent screw 23. For example, the processor can be configured to determine the dosage administered from the injection device 1 based on the detected time delay between the transmission of a pulse or time-varying signal by the sensor 96 and the reception of the reflected signal by the sensor 96. Alternatively or in addition, the processor can be configured to determine the dosage administered from the injection device 1 based on the attenuation of the signal.

[0110] In the foregoing embodiment, the button 18 includes an aperture 71 so that the dosage measurement device 60 can be inserted into the space 72 of the button 18. However, it should be understood that in an alternative embodiment (not shown), the aperture 71 is omitted. For example, the dosage measurement systems 60, 80, 90 can be integrated into the injection device 1, and thus the dosage measurement systems 60, 80, 90 are permanently received within the space 72 or within different components of the injection device 1.

[0111] In some embodiments (not shown), the dosage measurement systems 60, 80, 90 are removably attached or permanently fixed to a portion of the injection device 1 other than the button 18, such as the housing 3. be attached or permanently fixed.

[0112] In the foregoing embodiments, the attachment formations 74, 75 are in the form of protrusions 74 on the housings 61, 81, 91 of the dosage measurement devices 60, 80, 90 received in respective recesses 75 within the buttons 18. However, it should be understood that other types of engaging attachment formations or attachment methods can also be used. In one alternative embodiment (not shown), the attachment formation is in the form of a protrusion on the button 18 received in a respective recess within the housings 61, 81, 91 of the dosage measurement devices 60, 80, 90. Alternatively, the dosage measurement systems 60, 80, 90 can be adhesively bonded to the injection device 1. In one embodiment (not shown), the dosage measurement systems 60, 80, 90 are permanently integrated with the injection device 1. For example, the dosage measurement systems 60, 80, 90 can be integrated with the injection device 1 during the manufacture of the injection device 1. In one embodiment, the housings 61, 81, 91 of the dosage measurement systems 60, 80, 90 are omitted, and instead one or more components of the injection device 1, such as the button 18, the drive sleeve 21, and / or the housing 3, house the components of the dosage measurement systems 60, 80, 90.

[0113] Referring now to FIG. 17, a drug delivery system according to a fourth embodiment of the present invention is shown. The drug delivery system is similar to the measurement delivery system described above with reference to the second embodiment of the present invention, and like functions retain the same reference numerals. The drug delivery system includes a drug delivery device 1 and a dosage measurement system 100.

[0114] The drug delivery device 1 is in the form of an injection device 1. The difference between the dosage measurement system 80 of the second embodiment and the dosage measurement system 100 of the fourth embodiment is that the dosage measurement system 100 is integrated with the injection device 1. In the present embodiment, the dosage measurement system 100 is attached inside the drive sleeve 21. However, it should be understood that alternatively, the dosage measurement system 100 can also be attached to one or more other components of the injection device 1, such as the housing 3, the button 18, and / or the clutch plate 19.

[0115] In some embodiments (not shown), the housing 101 is integrally formed with components of the injection device 1, such as the housing 3, the button 18, and / or the clutch plate 19.

[0116] As described above, the dosage measurement system 100 includes a sensor unit (not shown), a battery (not shown), a processor (not shown), a computer-readable medium (not shown), and a user interface (not shown), such as a buzzer. The sensor unit is configured to transmit a signal reflected by the end face 23A of the male screw 23, whereby the reflected signal is detected by the sensor unit. A processor (not shown) can be configured to determine the dosage administered from the injection device 1 based on the characteristics of the reflected signal detected by the sensor unit.

[0117] The dosage measurement system 100 includes a housing 101 that houses one or more of the components of the dosage measurement system 100. However, it should be understood that in some embodiments (not shown), the housing can be omitted, and thus the components of the dosage measurement system 100 are directly attached to the injection device 1.

[0118] In the foregoing embodiments, an optical or acoustic sensor was utilized. However, in addition to, or instead of, an optical or acoustic sensor, other types of sensors can also be used. For example, the sensor can include a magnetic sensor, such as a Hall effect sensor. In such an example, one or more An upper magnet (not shown) can be attached, and thus, as a result of the axial movement of the male screw 23, the magnetic field detected by the sensor fluctuates. In another example, a capacitance sensor can be used, and an element that affects the capacitance between two plates provided within the sensor unit is provided on the male screw 23. In other examples, a mechanical sensor can be used together with a mechanical switch and / or a track to detect the relative movement of the male screw 23 with respect to components of the injection device 1 such as the housing 3 or the drive sleeve 21. In some embodiments (not shown), the sensor unit includes a plurality of sensors of one or more types.

[0119] In yet another embodiment (not shown), the dosage measurement system includes a sensor unit that includes an ultrasonic transducer. Optionally, the ultrasonic transducer can also be attached to an external member of the injection device 1, such as the proximal surface 18A of the button 18. The ultrasonic transducer is configured to transmit ultrasonic waves that travel through the button 18 and are reflected by the end face 23A of the male screw 23, and the reflected ultrasonic waves are detected by the ultrasonic transducer or another ultrasonic sensor. A processor (not shown) is configured to determine the dosage administered from the injection device 1 based on the characteristics of the reflected signal detected by the ultrasonic transducer, and the characteristics of the signal depend on the distance D between the ultrasonic transducer and the end face 23A of the male screw 23. For example, the processor can be configured to determine the dosage administered from the injection device 1 based on the detected time delay between the transmission of the ultrasonic signal by the ultrasonic transducer and the reception of the reflected signal by the ultrasonic transducer. Alternatively or in addition, the processor can be configured to determine the dosage administered from the injection device 1 based on the attenuation of the ultrasonic signal. Advantageously, the ultrasonic transducer can be adapted to an existing drug delivery device without requiring modification of the drug delivery device. This is because the ultrasonic signal can travel through the components, and thus there is no need to provide an aperture within the components of the drug delivery device to facilitate the movement of the signal between the transducer and the male screw. This also becomes possible when the components of the drug delivery device are manufactured from, for example, plastic, in addition to the magnets provided on the male screw detected by a magnetic sensor if a magnetic sensor is used.

[0120] Referring now to FIG. 18, a schematic view of a drug delivery system according to a fifth embodiment of the present invention is shown. The drug delivery system includes a drug delivery device 111 and a dosage measurement system 110.

[0121] The drug delivery device 111 is in the form of an injection device 111. The drug delivery device 111 includes a housing 112, and the housing 112 houses a dosing mechanism including a drug reservoir (not shown) and a plunger (not shown), a dosing member in the form of a male screw 113, a drive sleeve 114, and a drive unit 115.

[0122] The drive unit 115 is configured to rotate the drive sleeve 114 relative to the housing 112. The drive sleeve 114 engages with the male screw 113, and thus when the drive sleeve 114 rotates, the male screw 113 rotates. The male screw 113 and the drive sleeve 114 can engage via, for example, a screw interface (not shown).

[0123] The male screw 113 engages with the housing 112, and thus when the male screw 113 rotates relative to the housing 112, the male screw 113 is axially displaced relative to the housing 112, and thus the plunger moves within the drug reservoir to dispense the drug from the drug reservoir. Thus, when the drive unit 115 operates, the drive sleeve 114 rotates, and thus the male screw 113 moves axially relative to the housing 112 to dispense the drug from the drug reservoir.

[0124] The drive unit 115 includes a biasing member 116 and a locking mechanism 117, and the locking mechanism 117 is connected to an actuator 118. The biasing member 116 is configured to bias the drive sleeve 114 to rotate relative to the housing 112. The biasing member 116 is attached to a mandrel 116A, and thus the first end of the biasing member 116 is connected to the mandrel 116A. The second end of the biasing member 116 is connected to the drive sleeve 114 by a connecting member 119. In this embodiment, the connecting member 119 is fixed relative to the second end of the biasing member 116 and is received within a groove (not shown) on the inner surface of the drive sleeve 114, and thus the connecting member 119 is non-rotatably fixed relative to the drive sleeve 114.

[0125] The locking mechanism 117 initially prevents the biasing member 116 from rotating the drive sleeve 114 relative to the housing 112. The locking mechanism 117 is connected to the actuator 118, and thus the actuator 118 is operable to release the drive sleeve 114. The locking mechanism 117 can include, for example, a locking pin (not shown), which initially engages the second end of the biasing member 116 to prevent movement of the biasing member 116 relative to the housing 112. By the user actuating the actuator 118, the locking pin can be disengaged from the second end of the biasing member 116. However, the locking mechanism can have a different arrangement, for example, in one embodiment (not shown), it includes an electromagnetic latch that operates to release the biasing member.

[0126] To operate the drug delivery device 111, the user actuates the actuator 118, as a result of which the locking mechanism 117 releases the biasing member 116, and thus the drive sleeve 114 rotates relative to the housing 112. Thereby, the lead screw 113 moves axially relative to the housing 112 while rotating relative to the housing 112, and thus a plunger (not shown) moves axially within the drug reservoir, and thus drug is dispensed from the drug reservoir. The drug reservoir can be fluidly connected to, for example, a needle to deliver the drug to a patient.

[0127] The dosage measurement system 110 includes a sensor unit 120 having a sensor 121 and a processor (not shown). In this embodiment, the sensor 121 is an optical sensor 121 having a light source (not shown) and a light detector (not shown). In this embodiment, the sensor unit 120 is attached to a mandrel 116A that supports the biasing member 116. However, it should be understood that in an alternative embodiment (not shown), the sensor unit 120 is attached to a different member of the drug delivery device 111, such as the housing 112.

[0128] Sensor 121 is configured to transmit a signal reflected by the end face 113A of the male screw 113, whereby the reflected signal is detected by the sensor 121. In some embodiments (not shown), the sensor unit 120 further includes a transmission member (not shown), such as an optical guide, that transmits a signal from the sensor 121 towards the end face 113A of the male screw 113.

[0129] A processor (not shown) is configured to determine the dosage administered from the injection device 111 based on the characteristics of the reflected signal detected by the sensor unit 120, and the characteristics of the signal depend on the distance between the sensor unit 120 and the end face 113A of the male screw 113. For example, the processor can be configured to determine the dosage administered from the injection device 111 based on the detected time delay between the transmission of a pulse or time-varying signal by the sensor 121 and the reception of the reflected signal by the sensor 121. Alternatively or in addition, the processor can be configured to determine the dosage administered from the injection device 111 based on the attenuation of the signal.

[0130] In an alternative embodiment (not shown), the sensor 121 is instead directed towards a different member of the male screw 113, and thus the sensor 121 detects the axial displacement of the said different member of the male screw 113. For example, the sensor 121 can be configured to transmit a signal reflected by a distal-facing surface (not shown) of the male screw 113, whereby the reflected signal is detected by the sensor 121. In one such embodiment, the male screw 113 moves towards the sensor 121 when the drug is administered, and thus the distance between the sensor 121 and the surface of the male screw decreases.

[0131] In another embodiment (not shown), sensor 121 is configured to transmit a signal reflected by a component of the drive mechanism other than the parent screw 113. For example, the drive sleeve 114 can include a dosing member, and sensor 121 is configured to transmit a signal reflected by the drive sleeve 114 to detect the axial displacement of the drive sleeve 114. A processor (not shown) is configured to determine the dosage administered from the injection device 111 based on the characteristics of the reflected signal detected by the sensor unit 120, and the characteristics of the signal depend on the distance between the sensor unit 120 and the drive sleeve 114. Alternatively, the dosing member can include a plunger rod (not shown) that couples the parent screw 113 to a piston within the drug reservoir, and sensor 121 is configured to transmit a signal reflected by the plunger rod to detect the axial displacement of the plunger rod. A processor (not shown) is configured to determine the dosage administered from the injection device 111 based on the characteristics of the reflected signal detected by the sensor unit 120, and the characteristics of the signal depend on the distance between the sensor unit 120 and the plunger rod.

[0132] In this embodiment, the biasing member 116 is in the form of a torsion spring 116. However, it should be understood that other types of biasing members are also contemplated within the scope of the present invention. In a further embodiment (not shown), the biasing member is omitted and instead the drive unit includes an electric motor that operates to rotate the drive sleeve and thus dispense the drug from the drug reservoir. Alternatively, the drive unit can include a component that is manually rotated by the user to rotate the drive sleeve to dispense the drug.

[0133] In some embodiments (not shown), the male threads 13, 113 and the drive sleeves 21, 114 are omitted, and instead the drive mechanism has a different arrangement of the dosing member that moves axially within the housing 3, 112 to dispense the medicament from the medicament reservoir. For example, the drive mechanism can include a coil spring configured to axially bias the dosing member within the housing to dispense the medicament from the medicament reservoir. The dosing member includes a rod connected to a piston or plunger within the medicament reservoir. The locking mechanism initially holds the coil spring in a compressed position to prevent the coil spring from moving the rod within the housing to dispense the medicament. The user depresses the actuator to release the locking mechanism, and thus the coil spring is released to move the rod axially within the housing to dispense the medicament. The sensor unit is configured to detect the axial movement of the dosing member, and in this embodiment, the dosing member is the rod. More specifically, the sensor is configured to transmit a signal reflected by a member of the rod, and the reflected signal is detected by the sensor to detect the axial displacement of the rod. The processor is configured to determine the dosage dispensed from the injection device 1, 111 based on the characteristics of the reflected signal detected by the sensor unit, and the characteristics of the signal depend on the distance between the sensor unit and the rod.

[0134] In some embodiments (not shown), the dosage measurement systems 60, 80, 90, 100, 110 include a first member and a second member attachable to the first member. The second member can be releasably attachable to the first member. The first member of the dosage measurement devices 60, 80, 90, 100, 110 is configured to engage one or more attachment formations (not shown) configured to engage corresponding attachment formations (not shown) on the second member. It can include. The mounting formations of the first or second member can include protrusions that engage respective recesses of the other of the first and second members, and thus the second member can be clipped to the first member. However, in an alternative embodiment (not shown), the second member is attached to the first member via a different arrangement, for example, received within a recess in the first member, and thus it should be understood that the first and second members are held together via friction. Optionally, the first and second members can include engagement elements, such as rails, that engage grooves, thereby ensuring a specific rotational direction of the first member with respect to the second member when the second member is attached to the first member.

[0135] By the dosing measurement systems 60, 80, 90, 100, 110 including the first and second members, the first member can be attached to or integrated with the injection devices 1, 111, and the second member can be removably attached to the first member. Thus, by removing the second member from the first member and attaching that second member to the first member of a different injection device 1, 111, the injection devices 1, 111 and the first member can be disposed of, and the second member can be reused. One or more of a battery, user interface, communication module, processor, and sensor can be incorporated into the second member. Thus, by attaching the second member to the first member of a further injection device, these relatively expensive components can be reused with the further injection device.

[0136] In one embodiment, the first member includes a transmission member, such as an optical waveguide, fixed to the injection devices 1, 111. The second member includes a battery, a processor, and a sensor. The second member is attached to the first member, such that the transmission member and the sensor form a sensor unit, and the transmission member is capable of transmitting a signal emitted by the sensor towards the detection element and also transmitting a reflected signal back towards the sensor. After drug delivery is completed, the second member is removed from the first member, and the first member is disposed of together with the drug delivery device. In another embodiment (not shown), the first member includes a support member fixed to the injection devices 1, 111 and a sensor provided on the support member. The second member includes a battery and a processor. The second member is attached to the first member, such that the sensor is connected to the processor, and thus the processor is capable of determining the dosage administered from the drug reservoir based on the measured axial displacement of the displacement member. After drug delivery is completed, the second member is removed from the first member, and the first member is disposed of together with the drug delivery device.

[0137] In the foregoing embodiments, the drug delivery devices 1, 111 include injection devices. The injection devices can include pen injection devices and auto-injectors. However, it should be understood that the drug delivery system can also include different types of drug delivery devices. For example, the drug delivery device can include a patch device that is attached to the injection site of the patient. The drug delivery device can also be a pump device.

[0138] Regarding the above embodiments, although they have been described in relation to the collection of data from an insulin syringe pen, it should be noted that the embodiments of the present invention can also be used for other purposes, such as monitoring the injection of other drugs.

[0139] The terms "drug" or "agent" are used herein to describe one or more pharmaceutically active compounds. As described below, a drug or agent can include at least one small molecule or macromolecule or a combination thereof in various types of formulations for the treatment of one or more diseases. Exemplary pharmaceutically active compounds include small molecules, polypeptides, peptides, and proteins (e.g., hormones, growth factors, antibodies, antibody fragments, and enzymes), carbohydrates and polysaccharides, and nucleic acids, di single-stranded or double-stranded DNA (including naked and cDNA), RNA, antisense nucleic acids such as antisense DNA and RNA, small interfering RNA (siRNA), ribozymes, genes, and oligonucleotides. Nucleic acids can be incorporated into molecular delivery systems such as vectors, plasmids, or liposomes. Mixtures of one or more of these drugs are also contemplated.

[0140] The term "agent delivery device", also referred to hereinafter as "drug delivery device", shall include any type of device or system configured to administer a drug to a human or animal body. Without limitation, a drug or agent delivery device can be an injection device (e.g., a syringe, pen-type syringe, autoinjector, large volume device, pump, cannulation system, or other device configured for intravitreal, subcutaneous, intramuscular, or intravascular delivery), a skin patch (e.g., osmotic, chemical, microneedle), an inhaler (e.g., nasal or pulmonary), an implant (e.g., a coated stent, capsule), or a gastrointestinal delivery system. The drugs described herein can be particularly useful in injection devices including needles, e.g., small gauge needles.

[0141] A drug or medicament can be contained in a primary package or “drug container” adapted for use in a drug delivery device. The drug container can be, for example, a cartridge, syringe, reservoir, or other vessel configured to provide a chamber suitable for containing one or more pharmaceutically active compounds (e.g., for short-term or long-term containment). For example, in some cases, the chamber can be designed to contain the drug for at least one day (e.g., from one day to at least 30 days). In some cases, the chamber can be designed to contain the drug for about one month to about two years. The containment can be carried out at room temperature (e.g., about 20 °C) or refrigerated temperature (e.g., about -4 °C to about 4 °C). In some cases, the drug container can be or can include a dual-chamber cartridge configured to separately contain each of two or more components of a pharmaceutical formulation (e.g., a drug and a diluent, or two different types of drugs) in each chamber. In such cases, the two chambers of the dual-chamber cartridge can be configured to allow mixing between two or more components of the drug or medicament before and / or during dosing into a human or animal body. For example, the two chambers can be configured to be in fluid communication with each other (e.g., via a conduit between the two chambers) and to allow mixing of the two components by the user before dosing, if desired. Alternatively or additionally, the two chambers can be configured to allow mixing upon dosing of the components into a human or animal body.

[0142] The drug delivery devices and drugs described in the present invention can be used for the treatment and / or prevention of many different types of disorders. Exemplary disorders include, for example, diabetes or complications associated with diabetes such as diabetic retinopathy, thromboembolic disorders such as deep vein thrombosis or pulmonary embolism. Further exemplary disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and / or rheumatoid arthritis.

[0143] Exemplary drugs for the treatment and / or prevention of diabetes or complications associated with diabetes include insulin, such as human insulin, or human insulin analogs or derivatives, glucagon-like peptide (GLP-1), GLP-1 analogs or GLP-1 receptor agonists, or analogs or derivatives thereof, dipeptidyl peptidase-4 (DPP4) inhibitors, or pharmaceutically acceptable salts or solvates thereof, or mixtures of any of these. As used herein, the term "derivative" refers to any substance that is structurally similar enough to have substantially the same functionality or activity (e.g., therapeutic effect) as the original substance.

[0144] Exemplary insulin analogs are Gly(A21), Arg(B31), Arg(B32) human insulin (insulin glargine); Lys(B3), Glu(B29) human insulin; Lys(B28), Pro(B29) human insulin; Asp(B28) human insulin; human insulin in which proline at position B28 may be replaced by Asp, Lys, Leu, Val or Ala and Lys at position B29 may be replaced by Pro; Ala(B26) human insulin; Des(B28-B30) human insulin; Des(B27) human insulin and Des(B30) human insulin.

[0145] Exemplary insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin; B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl human insulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29 human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin; B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl-ThrB29LysB30 human insulin; B29-N-(N-palmitoyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(omega-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(omega-carboxyheptadecanoyl) human insulin. Exemplary GLP-1, GLP-1 analogs and GLP-1 receptor agonists are, for example, lixisenatide / AVE0010 / ZP10 / Lixumia, exenatide / exendin-4 / Byetta / Bydureon / ITCA650 / AC-2993 (a 39 amino acid peptide produced by the salivary gland of the Gila monster), liraglutide / Victoza, semaglutide, taspoglutide, Symlin / Albiglutide, dulaglutide, r exendin-4, CJC-1134-PC, PB-1023, TTP-054, langlenatide / HM-11260C, CM-3, GLP-1 erigen, ORMD-0901, NN-9924, NN-9926, NN-9927, nodexen, Biadol-GLP-1, CVX-096, ZYOG-1, ZYD-1, GSK-2374697, DA-3091, MAR-701, MAR709, ZP-2929, ZP-3022, TT-401, BHM-034, MOD-6030, CAM-2036, DA-15864, ARI-2651, ARI-2255, exenatide-XTEN and glucagon-Xten.

[0146] Exemplary oligonucleotides are, for example, the cholesterol-lowering antisense therapeutic agent mipomersen / Kynamro for the treatment of familial hypercholesterolemia.

[0147] Exemplary DPP4 inhibitors are vildagliptin, sitagliptin, denagliptin, saxagliptin, and berberine.

[0148] Exemplary hormones include pituitary hormones or hypothalamic hormones or regulatory active peptides and their antagonists, for example, gonadotropins (folitropin, lutropin, chorionic gonadotropin, menotropin), somatropin (Somatropine) (Somatropin), desmopressin, terlipressin, gonadorelin, triptorelin, leuprorelin, buserelin, nafarelin, and goserelin.

[0149] Exemplary polysaccharides include glucosaminoglycans, hyaluronic acid, heparin, low molecular weight heparin or ultra-low molecular weight heparin or their derivatives, or sulfated polysaccharides such as the polysaccharides described above in poly-sulfated form, and / or their pharmaceutically acceptable salts. Examples of pharmaceutically acceptable salts of poly-sulfated low molecular weight heparin are enoxaparin sodium Lithium. Examples of hyaluronic acid derivatives are hylan G-F20 / synvisc, sodium hyaluronate.

[0150] As used herein, the term "antibody" refers to an immunoglobulin molecule or an antigen-binding portion thereof. Examples of antigen-binding portions of immunoglobulin molecules include F(ab) and F(ab’)2 fragments that retain the ability to bind to an antigen. Antibodies can be polyclonal antibodies, monoclonal antibodies, recombinant antibodies, chimeric antibodies, deimmunized or humanized antibodies, fully human antibodies, non-human (e.g., murine) antibodies, or single-chain antibodies. In some embodiments, the antibody has effector functions and is capable of fixing complement. In some embodiments, the antibody has a reduced or no ability to bind to an Fc receptor. For example, the antibody can be an isotype or subtype, an antibody fragment, or a mutant that does not assist in binding to an Fc receptor, e.g., having a mutation or deletion in the Fc receptor-binding region.

[0151] The term "fragment" or "antibody fragment" refers to a polypeptide (e.g., an antibody heavy chain and / or light chain polypeptide) derived from an antibody polypeptide molecule that does not include the full-length antibody polypeptide but still includes at least a portion of the full-length antibody polypeptide capable of binding to an antigen. Antibody fragments can include cleaved portions of the full-length antibody polypeptide, but the term is not limited to such cleaved fragments. Antibody fragments useful in the present invention include, for example, Fab fragments, F(ab’)2 fragments, scFv (single-chain Fv) fragments, linear antibodies, single-specific or multispecific antibody fragments, e.g., bispecific, trispecific, and multispecific antibodies (e.g., diabodies, tribodies, tetrabodies), minibodies, chelated recombinant antibodies, tribodies or bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIPs), binding domain immunoglobulin fusion proteins, camelized antibodies, and VHH-containing antibodies. Additional examples of antigen-binding antibody fragments are known in the art.

[0152] The term "complementary determining region" or "CDR" refers to short polypeptide sequences within the variable regions of both the heavy and light chain polypeptides that primarily play a role in mediating specific antigen recognition. The term "framework region" refers to the amino acid sequences within the variable regions of both the heavy and light chain polypeptides that are not CDR sequences and primarily play a role in maintaining the proper arrangement of the CDR sequences to enable antigen binding. Although the framework region itself is not typically directly involved in antigen binding, as is known in the art, certain residues within the framework region of a particular antibody can be directly involved in antigen binding or can affect the ability of one or more amino acids within the CDR to interact with the antigen.

[0153] Exemplary antibodies include anti-PCSK-9 mAb (e.g., alirocumab), anti-IL-6 mAb (e.g., sarilumab), and anti-IL-4 mAb (e.g., dupilumab).

[0154] The compounds described herein can be used in pharmaceutical formulations comprising (a) a compound or a pharmaceutically acceptable salt thereof, and (b) a pharmaceutically acceptable carrier. The compounds can also be used in pharmaceutical formulations containing one or more other active pharmaceutical ingredients, or in pharmaceutical formulations where the compound or their pharmaceutically acceptable salts are the sole active ingredient. Thus, the pharmaceutical formulations of the present disclosure include any formulation made by mixing a compound described herein with a pharmaceutically acceptable carrier.

[0155] Any pharmaceutically acceptable salts of the drugs described herein are contemplated for use in drug delivery devices. Pharmaceutically acceptable salts include, for example, acid addition salts and basic salts. It forms. The acid addition salts are, for example, HCl or HBr salts. The basic salts are, for example, alkali or alkaline earth metals, such as Na+, or K+, or Ca2+, or ammonium ions N+(R1)(R2)(R3)(R4), (wherein R1 to R4 are independently of each other: hydrogen, optionally substituted C1-C6-alkyl group, optionally substituted C2-C6-alkenyl group, optionally substituted C6-C10-aryl group, or optionally substituted C6-C10-heteroaryl group), and are salts having a cation selected from the group consisting of). Further examples of pharmaceutically acceptable salts are known to those skilled in the art.

[0156] Pharmaceutically acceptable solvates are, for example, hydrates or alkanolates such as methanolate or ethanolate.

[0157] Without departing from the full scope and spirit of the present invention, various components of the substances, compositions, devices, methods, systems, and embodiments described herein can be modified (added and / or deleted), and it will be understood by those skilled in the art that the present invention encompasses such modifications and any equivalents thereof.

Claims

1. 1. A dose measuring system for a drug delivery device comprising a drug reservoir and a dosing mechanism including a dosing member axially movable to dispense a drug from the drug reservoir, the dose measuring system comprising: A sensor unit configured to measure an axial displacement of the dosing member; and a processor configured to determine a dose dispensed from the medication reservoir based on the measured axial displacement of the dosage member.

2. 10. The dosage measuring system of claim 1, wherein the sensor unit is configured to be positioned such that the dispensing member moves away from the sensor unit to dispense medicament from the medicament reservoir.

3. 3. The dosage measuring system according to claim 1 or 2, wherein the sensor unit is configured to transmit a signal, the signal being reflected from the dispensing member, the sensor unit being configured to detect the reflected signal.

4. 4. The dosage measuring system according to claim 3, wherein the sensor unit comprises a transmission member, and the signal is transmitted through the transmission member, preferably the transmission member comprising a light guide.

5. 5. The dosage measuring system of claim 1, wherein the dispensing member includes a lead screw, and the dispensing mechanism further includes a drive member configured to rotate to axially displace the lead screw relative to the drive member to dispense the drug from the drug reservoir.

6. 6. The dosage measuring system of claim 5, wherein the sensor unit is configured to transmit a signal that travels within the drive member.

7. The dosage measuring system according to any one of claims 1 to 6, wherein the sensor unit is integrated with the drug delivery device.

8. A dosage measuring system according to any one of claims 1 to 6, wherein the sensor unit is removably attachable to the medication delivery device.

9. A dosage measuring system according to any preceding claim, wherein the medication delivery device includes an actuator operable by a user to dispense the medication, and the sensor unit is configured to be attached to the actuator.

10. 10. The dosage measuring system of claim 9, wherein the actuator includes a space, and the sensor unit is configured to be at least partially received within the space.

11. 11. A dose measuring system according to claim 9 or 10, wherein the processor is configured to determine the dose dispensed from the drug reservoir only when the actuator is actuated.

12. A dosage measuring system according to any one of claims 9 to 11, wherein the actuator is configured to move from a first position to a second position when actuated, and the sensor unit is configured to be attached to the actuator so as to move together with the actuator between the first and second positions.

13. The dosage measuring system includes a first member configured to be secured to the medication delivery device and a second member removably attachable to the first member, preferably a second member. A dosage measuring system according to any preceding claim, wherein the component comprises a processor.

14. 14. A dosage measuring system according to claim 13 when dependent on claim 4, wherein the first member comprises a transmission member.

15. A dose measuring device comprising the dose measuring system of claim 1.

16. 1. A drug delivery system comprising: a drug delivery device including a drug reservoir and a dispensing mechanism including an axially movable dispensing member for dispensing a drug from the drug reservoir; and the dosage measuring system of claim 1.

17. 17. The drug delivery system of claim 16, wherein the drug reservoir contains a drug.

18. 1. A method of determining a dose of a drug dispensed from a drug delivery device, the drug delivery device including a drug reservoir and a dosing member axially movable to dispense a drug from the drug reservoir, comprising: Measuring an axial displacement of the dosing member; and determining a dose dispensed from the drug reservoir based on the measured axial displacement of the dispensing member.

19. 20. The method of claim 18, wherein the dispensing member includes a lead screw, and the dispensing mechanism further includes a drive member configured to rotate to axially displace the lead screw relative to the drive member to dispense the drug from the drug reservoir.

20. 20. The method of claim 18 or 19, wherein the sensor unit is configured to be positioned such that the dispensing member moves away from the sensor unit to dispense medicament from the medicament reservoir.

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