Patent Description:
A variety of diseases exists that require regular treatment by injection of a medicament. Such injection can be performed by using injection devices, which are applied either by medical personnel or by patients themselves. As an example, type-<NUM> and type-<NUM> diabetes can be treated by patients themselves by injection of insulin doses, for example once or several times per day. For instance, a pre-filled disposable insulin pen can be used as an injection device. Alternatively, a re-usable pen may be used. A re-usable pen allows replacement of an empty medicament cartridge by a new one. Either pen may come with a set of one-way needles that are replaced before each use. The insulin dose to be injected can then for instance be manually selected at the insulin pen by turning a dosage knob and observing the actual dose from a dose window or display of the insulin pen. The dose is then injected by inserting the needle into a suited skin portion and pressing an injection button of the insulin pen. To be able to monitor insulin injection, for instance to prevent false handling of the insulin pen or to keep track of the doses already applied, it is desirable to measure information related to a condition and/or use of the injection device, such as for instance information on the injected insulin dose.

<CIT> discloses a drug injection device comprising expelling means for expelling an amount of drug from a reservoir, the expelling means comprising setting means allowing a user to set a dose to be expelled, and actuation means for releasing the drug expelling means to expel the set dose. The actuation means comprises an actuation member adapted to be moved between an initial position, an intermediate position, and an actuated position in which the expelling means is actuated to expel the set dose. The device further comprises an electronically controlled capturing system for capturing data representing the amount of drug expelled from the reservoir by the expelling means, and switch means for starting initialization of the capturing system when the actuation member is moved to its intermediate position.

<CIT> discloses a supplementary device for attachment to an injection device. The supplementary device comprises a first imaging arrangement and a second imaging arrangement each configured to capture an image of a moveable number sleeve of the injection device from different respective angles. The supplementary device also comprises a plurality of light sources and a processor arrangement configured to control operation of the first imaging arrangement and the second imaging arrangement and the plurality of light sources and to receive image data from each of the imaging arrangements. The processor arrangement is configured to combine images captured by the first imaging arrangement and the second imaging arrangement into a single image.

<CIT> discloses systems, methods, and apparatus for attaching an automated dose setting apparatus to a medication delivery device, receiving a first signal from an analyte monitoring system, the first signal indicating a dose of medication to be administered, and driving a dose knob of the medication delivery device with the automated dose setting apparatus to set a dose corresponding with the dose of medication to be administered.

It is an object of the present disclosure to provide an improved medicament delivery device and method of determining a dosage of medicament dispensed from a medicament delivery device. According to the present disclosure, there is provided a dosage measurement system for a medicament delivery device, wherein the medicament delivery device comprises a medicament reservoir, a lead screw and a drive sleeve that is rotatable to axially displace the lead screw relative to the drive sleeve to dispense medicament from the medicament reservoir, the dosage measurement system comprising: a sensor unit configured to measure rotation of at least one of the drive sleeve and lead screw, wherein the sensor unit is configured to transmit a light signal that travels within the drive sleeve and is reflected from said at least one of the drive sleeve and lead screw; and, a processor configured to determine a dosage dispensed from the medicament reservoir based on the measured rotation of said at least one of the drive sleeve and lead screw. In some embodiments, the sensor unit may be attached to the end of an existing medicament delivery device without requiring major modification of the medicament delivery device. For instance, the sensor unit may be attached to, for example, the proximal end of the medicament delivery device to measure the rotation of the lead screw or drive sleeve.

In one embodiment, the sensor unit is configured to be at least partially located within the drive sleeve. This helps to reduce the size of the medicament delivery device.

In one embodiment, the sensor unit is configured to transmit a signal such that said signal is reflected from said at least one of the drive sleeve and lead screw, the sensor unit configured to receive said reflected signal. The sensor unit may comprise a transmission member, said signal being transmitted through the transmission member. Thus, the transmission member helps to direct the signal towards the dispensing member. Therefore, the sensor itself does not need to be positioned in proximity to the dispensing member. The transmission member may comprise a light guide. In one embodiment, the transmission member extends into the drive sleeve.

In one embodiment, the dosage measurement system comprises a first part configured to be fixed to a medicament delivery device and a second part that is removably attachable to the first part and, preferably, wherein the second part comprises the processor. Thus, the first part may be disposed of with the medicament delivery device and the second part may be attached to the first part of a further medicament delivery device and re-used. In one embodiment, the first part comprises the transmission member. Thus, the second part may be removably attachable to the first part comprising the transmission member.

In one embodiment, the drive sleeve engages the lead screw. In one embodiment, the lead screw is at least partially within the drive sleeve.

In one embodiment, the sensor unit is configured such that the signal is reflected from a radially-inwardly facing surface of the drive sleeve.

In one embodiment, said at least one of the drive sleeve and lead screw comprises one or more detection elements that are detectable by the sensor unit.

In one embodiment, the sensor unit is integrated with the medicament delivery device.

In one embodiment, the sensor unit is removably attachable to the medicament delivery device. Therefore, the medicament delivery device can be disposed of and the sensor unit detached from the medicament delivery device for re-use prior to disposal of the medicament delivery device.

In one embodiment, the sensor unit comprises at least one of an optical sensor, magnetic sensor or capacitive sensor.

In one embodiment, the dosage measurement system comprises a display. The display may be configured to display dosage information.

In one embodiment, the medicament delivery device comprises an actuator that is actuatable by a user to dispense medicament, and wherein the sensor unit is configured to be mounted to the actuator. The actuator may comprise a space, and the sensor unit may be configured to be at least partially received in the space.

In one embodiment, the sensor unit is configured to measure rotation of the drive sleeve and the processor is configured to determine a dosage dispensed from the medicament reservoir based on the measured rotation of the drive sleeve. The sensor unit may be configured such that said signal is reflected from a radially-inwardly facing surface of the drive sleeve. In another embodiment, the sensor unit is configured to measure rotation of the lead screw and the processor is configured to determine a dosage dispensed from the medicament reservoir based on the measured rotation of the lead screw.

According to the present disclosure there is also provided a dosage measurement device comprising a dosage measurement system according to the disclosure.

According to the present disclosure, there is also provided a medicament delivery system comprising: a medicament delivery device comprising a medicament reservoir, a lead screw and a drive sleeve that is rotatable to axially displace the lead screw relative to the drive sleeve to dispense medicament from the medicament reservoir; and, a dosage measurement system according to the disclosure. In one embodiment, the medicament reservoir contains medicament.

According to the present disclosure, there is provided a method of determining a dosage of medicament dispensed from a medicament delivery device, wherein the medicament delivery device comprises a medicament reservoir, a lead screw and a drive sleeve that is rotatable to axially displace the lead screw relative to the drive sleeve to dispense medicament from the medicament reservoir, the method comprising: measuring the rotation of at least one of the drive sleeve and lead screw during the dispensing of medicament from the medicament reservoir by transmitting a signal that travels within the drive sleeve and is reflected from said at least one of the drive sleeve and lead screw; and, determining the dosage dispensed from the medicament reservoir based on the measured rotation of said at least one of the drive sleeve and lead screw.

These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter.

A drug delivery device, as described herein, may be configured to inject a medicament into a patient. For example, delivery could be sub-cutaneous, intra-muscular, or intravenous. Such a device could be operated by a patient or care-giver, such as a nurse or physician, and can include various types of safety syringe, pen-injector, or auto-injector. The device can include a cartridge-based system that requires piercing a sealed ampule before use. Volumes of medicament delivered with these various devices can range from about <NUM> to about <NUM>. Yet another device can include a large volume device ("LVD") or patch pump, configured to adhere to a patient's skin for a period of time (e.g., about <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> minutes) to deliver a "large" volume of medicament (typically about <NUM> to about <NUM>).

The delivery devices described herein can also include one or more automated functions. For example, one or more of needle insertion, medicament injection, and needle retraction can be automated. Energy for one or more automation steps can be provided by one or more energy sources. Energy sources can include, for example, mechanical, pneumatic, chemical, or electrical energy. For example, mechanical energy sources can include springs, levers, elastomers, or other mechanical mechanisms to store or release energy. One or more energy sources can be combined into a single device. Devices can further include gears, valves, or other mechanisms to convert energy into movement of one or more components of a device.

The one or more automated functions of an auto-injector may each be activated via an activation mechanism. Such an activation mechanism can include an actuator, for example, one or more of a button, a lever, a needle sleeve, or other activation component. Activation of an automated function may be a one-step or multi-step process. That is, a user may need to activate one or more activation components in order to cause the automated function. For example, in a one-step process, a user may depress a needle sleeve against their body in order to cause injection of a medicament. Other devices may require a multi-step activation of an automated function. For example, a user may be required to depress a button and retract a needle shield in order to cause injection.

The term "distal" refers to a location that is relatively closer to a site of injection, and the term "proximal" refers to a location that is relatively further away from the injection site.

<FIG> is an exploded view of the components of a first embodiment of medicament delivery system comprising a medicament delivery device <NUM> and a dosage measurement system <NUM>.

In the present embodiment, the medicament delivery device <NUM> is in the form of an injection device <NUM>. The injection device <NUM> comprises a dose dial <NUM> in the form of a dial grip <NUM>, a body or housing <NUM> with an elongated window <NUM>, and a dose scale drum in the form of a number sleeve <NUM>.

The number sleeve <NUM> has an outer thread <NUM> on its outer peripheral surface extending in a helical pattern from a distal end to a proximal end. The number sleeve <NUM> carries indicia <NUM> which are printed on the number sleeve. The indicia <NUM> are on the number sleeve <NUM> in a helical pattern.

The injection device <NUM> further comprises a sliding element <NUM> configured as a gauge component with a sliding window <NUM>.

The injection device <NUM> further comprises a drive spring <NUM> in the form of a torsion spring <NUM>, a trigger button <NUM>, a clutch plate <NUM>, a last dose nut <NUM>, a drive sleeve <NUM>, a clutch spring <NUM>, a lead screw <NUM>, and a bearing <NUM> provided at a distal end of the lead screw <NUM>.

A cartridge holder <NUM> is provided that can be attached to the distal end of the housing <NUM> and that receives a cartridge <NUM> which is filled with a medicament and which has a bung (not shown) located inside the cartridge <NUM>. When the bearing <NUM> is moved in the distal direction, the bearing <NUM> displaces the bung such that medicament is dispensed from the cartridge <NUM> when a dispense interface such as a double ended needle cannula is attached to the distal end of the cartridge <NUM>.

The number sleeve <NUM> comprises an upper number sleeve part <NUM> referred to a number sleeve upper <NUM> and a lower number sleeve part <NUM> referred to as number sleeve lower <NUM>. The dose dial <NUM> and the button <NUM> are separate individual components. In the present embodiment, all components are located concentrically about a common principal longitudinal axis of the mechanism. The body or housing <NUM> may also be a body element that it fixed to an outer housing or casing.

The button <NUM> is permanently splined to the dose dial <NUM>. It is also splined to the number sleeve upper <NUM> when the button <NUM> is not pressed, but this spline interface is disconnected when the button <NUM> is pressed. When the button <NUM> is pressed, splines on the button <NUM> engage with splines on the housing <NUM> preventing rotation of the button <NUM> (and hence the dose dial <NUM>) during dispense. These splines disengage when the button <NUM> is released, allowing a dose to be dialled.

The dose dial <NUM> is axially constrained to the housing <NUM>. It is rotationally constrained, via the splined interface to the button <NUM>. The number sleeve lower <NUM> is rigidly fixed to the number sleeve upper <NUM> during assembly to form the number sleeve <NUM> and is a separate component to simplify number sleeve <NUM> mould tooling and assembly. This sub assembly is constrained to the housing <NUM> by holding elements (not shown) towards the distal end to allow rotation but not translation. The number sleeve lower <NUM> is marked with indices in the form of a sequence of numbers, which are visible through the window <NUM> of the sliding element <NUM> and the window <NUM> in the housing <NUM> to denote the dialled dose of medicament.

The clutch plate <NUM> is splined to the number sleeve <NUM>. It is also coupled to the drive sleeve <NUM> via a ratchet interface. The ratchet provides a detented position between the number sleeve <NUM> and the drive sleeve <NUM> corresponding to each dose unit and engages different ramped tooth angles during clockwise and anti-clockwise relative rotation. The sliding element <NUM> is constrained to prevent rotation but allow translation relative to the housing <NUM> via a splined interface. The sliding element <NUM> has a helical feature on its inner surface which engages with the helical outer thread <NUM> cut in the number sleeve <NUM> such that rotation of the number sleeve <NUM> causes axial translation of the sliding element <NUM>. This helical feature on the sliding element <NUM> also creates stop abutments against the end of the helical cut in the number sleeve <NUM> to limit the minimum and maximum dose that can be set.

The last dose nut <NUM> is located between the number sleeve <NUM> and the drive sleeve <NUM>. It is rotationally constrained to the number sleeve <NUM> via a splined interface. It moves along a helical path relative to the drive sleeve <NUM> via a threaded interface when relative rotation occurs between the number sleeve <NUM> and drive sleeve <NUM>. The drive sleeve <NUM> extends from the interface with the clutch plate <NUM> to the contact with the clutch spring <NUM>. A splined tooth interface with the number sleeve <NUM> is not engaged during dialling, but engages when the button <NUM> is pressed, preventing relative rotation between the drive sleeve <NUM> and number sleeve <NUM> during dispense.

A further splined tooth interface with the housing <NUM> prevents rotation of the drive sleeve <NUM> during dose setting. When the button <NUM> is pressed, the drive sleeve <NUM> and the housing <NUM> disengage allowing the drive sleeve <NUM> to rotate. The helical drive spring <NUM> is charged and stores energy during dose setting by the action of the user rotating the dose dial <NUM>. The spring energy is stored until the mechanism is triggered for dispense at which point the energy stored is used to deliver the medicament from the cartridge to the user. The drive spring <NUM> is attached at one end to the housing <NUM> and at the other end to the number sleeve <NUM>. The drive spring <NUM> is pre-wound upon assembly, such that it applies a torque to the number sleeve <NUM> when the mechanism is at zero units dialled. The action of rotating the dose dial <NUM> to set a dose rotates the number sleeve <NUM> relative to the housing <NUM> and charges the drive spring <NUM> further.

The lead screw <NUM> is rotationally constrained to the drive sleeve <NUM> via a splined interface. When rotated, the lead screw <NUM> is forced to move axially relative to the drive sleeve <NUM>, through a threaded interface (not shown) with the housing <NUM>. The bearing <NUM> is axially constrained to the lead screw <NUM> and acts on the bung within the liquid medicament cartridge <NUM>.

The axial position of the drive sleeve <NUM>, clutch plate <NUM> and button <NUM> is defined by the action of the clutch spring <NUM>, which applies a force on the drive sleeve <NUM> in the proximal direction. This spring force is reacted via the drive sleeve <NUM>, clutch plate <NUM> and button <NUM>, and when 'at rest' it is further reacted through the dose dial <NUM> to the housing <NUM>. The spring force ensures that the ratchet interface is always engaged. In the 'at rest' position, it also ensures that the button splines are engaged with the number sleeve <NUM> and that the drive sleeve teeth are engaged with the housing <NUM>. The housing <NUM> provides location for the liquid medication cartridge <NUM> and cartridge holder <NUM>, windows for viewing the dose number and the sliding element, and a feature on its external surface to axially retain the dose dial <NUM> (not shown). A removable cap fits over the cartridge holder <NUM> and is retained via clip features on the housing <NUM>.

<FIG> shows the inside of the sliding element <NUM> with the window <NUM> and a male thread feature <NUM> on the inner surface of the sliding element <NUM> that engages the outer thread <NUM> on the number sleeve <NUM> (see <FIG>). The thread feature <NUM> has a zero dose abutment <NUM> and a maximum dose abutment <NUM>. As shown in <FIG>, the outer thread <NUM> has a zero dose abutment <NUM> at one end of the thread <NUM> and a maximum dose abutment <NUM> at the other end of the outer thread <NUM> so that any dose size can be selected between zero and a pre-defined maximum, in increments to suit the medicament and user profile. The drive spring <NUM>, which has a number of pre-wound turns applied to it during assembly of the device, applies a torque to the number sleeve <NUM> and is prevented from rotating by the zero dose abutment.

As shown in <FIG>, the inner surface of the number sleeve <NUM> has a lead-in <NUM> followed by a groove <NUM> and an anchor point <NUM>. Automated assembly of the drive spring <NUM> into the number sleeve may be achieved by incorporating the large lead-in <NUM> and the groove feature <NUM>. As the drive spring <NUM> is rotated during assembly, a hook end <NUM> at the one end of the drive spring <NUM> (see <FIG>) locates in the groove feature <NUM> before engaging the anchor point <NUM> in the number sleeve <NUM>.

As shown in <FIG>, the drive spring <NUM> is formed from a helical wire with at least two different pitches. Both ends are formed from 'closed' coils <NUM>, i.e. the pitch equals the wire diameter and each coil contacts the adjacent coil. The central portion has 'open' coils <NUM>, i.e. the coils do not contact each other. Following assembly, compression in the drive spring <NUM> biases the number sleeve <NUM> axially relative to the housing <NUM> in a consistent direction, reducing the effects of geometric tolerances.

For selecting a dose, the user rotates the dial grip <NUM> clockwise. As shown in <FIG>, the button <NUM> has inner splines <NUM> for engaging corresponding splines <NUM> on the upper part of number sleeve <NUM> to create a splined interface <NUM>/<NUM>. The dial grip <NUM> is splined to the button <NUM>, wherein the button <NUM> has a further set of splines <NUM> for engagement with corresponding splines of the housing <NUM>. During dose selection, rotation of the dial grip <NUM> is transferred to the button <NUM>. The button <NUM> is in turn splined to the number sleeve upper <NUM> (during dose selection only) via the splines <NUM>. The number sleeve upper <NUM> is permanently fixed to the number sleeve lower <NUM> to form the number sleeve <NUM>. Therefore, rotation of the dial grip <NUM> generates an identical rotation in the number sleeve <NUM>. Rotation of the number sleeve <NUM> causes charging of the drive spring <NUM>, increasing the energy stored by the drive spring <NUM>. As the number sleeve <NUM> rotates, the sliding element <NUM> translates axially due to its threaded engagement with the number sleeve <NUM> thereby showing the value of the dialled dose.

As shown in <FIG>, the drive sleeve <NUM> has splines <NUM> for engaging corresponding splines <NUM> formed on the inside of the housing <NUM> to create a splined interface <NUM>/<NUM>. The drive sleeve <NUM> is prevented from rotating as the dose is set and the number sleeve <NUM> is rotated, due to the engagement of its splined teeth <NUM> with the teeth <NUM> of the housing <NUM>. Relative rotation therefore occurs between the clutch plate <NUM> that is driven by the number sleeve <NUM> and the drive sleeve <NUM> via the ratchet interface.

As shown in <FIG>, an end surface of the drive sleeve <NUM> is provided with angled teeth <NUM> and the clutch plate <NUM> is provided with angled teeth <NUM>. The angled teeth <NUM> of the drive sleeve <NUM> form the ratchet interface <NUM>/<NUM> together with the angled teeth <NUM> on the clutch plate <NUM>.

On the outer circumference of the clutch plate <NUM>, splined teeth <NUM> for engaging a corresponding groove on the number sleeve <NUM> are formed. The user torque required to rotate the dial grip <NUM> is a sum of the torque required to wind up the drive spring <NUM>, and the torque required to overhaul the ratchet interface <NUM>/<NUM>. The clutch spring <NUM> is designed to provide an axial force to the ratchet interface <NUM>/<NUM> and to bias the clutch plate <NUM> onto the drive sleeve <NUM>. This axial load acts to maintain the ratchet teeth <NUM>, <NUM> engagement of the clutch plate <NUM> and the drive sleeve <NUM>. The torque required to overhaul the ratchet interface <NUM>/<NUM> in the dose set direction is a function of the axial load applied by the clutch spring <NUM>, the clockwise ramp angle of the ratchet, the friction coefficient between the mating surfaces and the mean radius of the ratchet features. As the user rotates the dial grip <NUM> sufficiently to increment the mechanism by <NUM> increment, the number sleeve <NUM> rotates relative to the drive sleeve <NUM> by <NUM> ratchet tooth. At this point the ratchet teeth <NUM>, <NUM> re-engage into the next detented position. An audible click is generated by the ratchet re-engagement, and tactile feedback is given by the change in torque input required.

With no user torque applied to the dial grip <NUM>, the number sleeve <NUM> is prevented from rotating back under the torque applied by the drive spring <NUM>, solely by the ratchet engagement <NUM>/<NUM> between the clutch plate <NUM> and the drive sleeve <NUM>. The torque necessary to overhaul the ratchet interface <NUM>/<NUM> in the anti-clockwise direction is a function of the axial load applied by the clutch spring <NUM>, the anti-clockwise ramp angle of the ratchet teeth <NUM>,<NUM>, the friction coefficient between the mating surfaces and the mean radius of the ratchet features. The torque necessary to overhaul the ratchet interface <NUM>/<NUM> must be greater than the torque applied to the number sleeve <NUM> (and hence clutch plate <NUM>) by the drive spring <NUM>. The ratchet ramp angle is therefore increased in the anticlockwise direction to ensure this is the case whilst ensuring the dial-up torque is as low as possible. The user may choose to increase the selected dose by continuing to rotate the dial grip <NUM> in the clockwise direction. The process of overhauling the ratchet interfaces <NUM>/<NUM> between the number sleeve <NUM> and drive sleeve <NUM> is repeated for each dose increment. Additional energy is stored within the drive spring <NUM> for each dose increment and audible and tactile feedback is provided for each increment dialled by the re-engagement of the ratchet teeth <NUM>, <NUM>. The torque required to rotate the dial grip <NUM> increases as the torque required to wind up the drive spring <NUM> increases. The torque required to overhaul the ratchet interface <NUM>/<NUM> in the anti-clockwise direction must therefore be greater than the torque applied to the number sleeve <NUM> by the drive spring <NUM> when the maximum dose has been reached.

If the user continues to increase the selected dose until the maximum dose limit is reached, the number sleeve <NUM> engages with the maximum dose abutment <NUM> on the sliding element <NUM> (see <FIG>. This prevents further rotation of the number sleeve <NUM>, clutch plate <NUM> and dial grip <NUM>.

The last dose nut <NUM> is splined to the number sleeve <NUM> while the last dose nut <NUM> is threaded to the drive sleeve <NUM> such that relative rotation of the number sleeve <NUM> and the drive sleeve <NUM> during dose setting also causes the last dose nut <NUM> to travel along its threaded path towards a last dose abutment on the drive sleeve <NUM>. Depending on how many increments have already been delivered by the mechanism, during selection of a dose, the last dose nut <NUM> may contact its last dose abutment with the drive sleeve <NUM>. The abutment prevents further relative rotation between the number sleeve <NUM> and the drive sleeve <NUM> and therefore limits the dose that can be selected. The position of the last dose nut <NUM> is determined by the total number of relative rotations between the number sleeve <NUM> and the drive sleeve <NUM>, which have occurred each time the user sets a dose.

When a dose has been set, the user is able to deselect any number of increments from this dose. Deselecting a dose is achieved by the user rotating the dial grip <NUM> anti-clockwise. The torque applied to the dial grip <NUM> by the user is sufficient, when combined with the torque applied by the drive spring <NUM>, to overhaul the ratchet interface <NUM>/<NUM> between the clutch plate <NUM> and the drive sleeve <NUM> in the anti-clockwise direction. When the ratchet interface <NUM>/<NUM> is overhauled, anti-clockwise rotation occurs in the number sleeve <NUM> (via the clutch plate <NUM>), which returns the number sleeve <NUM> towards the zero dose position, and unwinds the drive spring <NUM>. The relative rotation between the number sleeve <NUM> and drive sleeve <NUM> causes the last dose nut <NUM> to return along its helical path, away from the last dose abutment.

As shown in <FIG>, the sliding element <NUM> has flanges or extensions on either side of the window area which cover the numbers printed on the number sleeve <NUM> adjacent to the dialled dose to ensure only the set dose number is made visible to the user. The injection device <NUM> includes a visual feedback feature in addition to the discrete dose number display. The distal end of the sliding element <NUM> has the extension <NUM> (see <FIG>) that creates a sliding scale through a window <NUM> in the housing <NUM>. Window <NUM> may be smaller than window <NUM>.

As a dose is set by the user, the sliding element <NUM> translates axially, the distance moved proportional to the magnitude of the dose set. This feature gives clear feedback to the user regarding the approximate size of the dose set. The dispense speed of the injection device <NUM> may be higher than for a manual injector device, so it may not be possible to read the numerical dose display during dispense. The sliding element <NUM> provides feedback to the user during dispense regarding dispense progress without the need to read the dose number itself.

The window <NUM> may be formed by an opaque element on the sliding element <NUM> revealing a contrasting coloured component <NUM> underneath. Alternatively, a revealable element <NUM> may be printed with coarse dose numbers or other indices to provide more precise resolution. In addition, this display simulates a syringe action during dose set and dispense.

To reduce dust ingress and prevent the user from touching moving parts, the viewing openings <NUM> and <NUM> in the housing <NUM> are covered by translucent windows. These windows <NUM>, <NUM> may be separate components, but in this embodiment they are incorporated into the housing <NUM> using 'twin-shot' moulding technology. A first shot of translucent material forms the internal features and the windows, and then a 'second shot' of opaque material forms the outer cover of the housing <NUM>.

Delivery of a dose is initiated by the user depressing the button <NUM> axially. When the button <NUM> (see <FIG>) is depressed, the splines <NUM> and <NUM> between the button <NUM> and the number sleeve <NUM> disengage, rotationally disconnecting the button <NUM> and dial grip <NUM> from the delivery mechanism.

As shown in <FIG>, the splines <NUM> on the button <NUM> engage with splines <NUM> on the housing <NUM> preventing rotation of the button <NUM> (and hence the dial grip <NUM>) during dispense. As the button <NUM> is stationary during dispense, it can be used in a dispense clicker mechanism. A stop feature in the housing <NUM> limits axial travel of the button <NUM> and reacts any axial abuse loads applied by the user, reducing the risk of damaging internal components.

As shown in <FIG>, the clutch plate <NUM>, arranged between the drive sleeve <NUM> and the button <NUM>, is moved axially by the button <NUM>. Moreover, the drive sleeve <NUM> is moved axially by the clutch plate <NUM>. As shown in <FIG>, the axial displacement of the drive sleeve <NUM> engages splines <NUM> on the drive sleeve <NUM> with splines <NUM> on the number sleeve <NUM> so that a splined tooth interface <NUM>/<NUM> is formed preventing relative rotation between the drive sleeve <NUM> and number sleeve <NUM> during dispense.

The splined tooth interface <NUM>/<NUM> (shown in <FIG>) between the drive sleeve <NUM> and the housing <NUM> disengages, so that the drive sleeve <NUM> can now rotate relative to the housing <NUM> and is driven by the drive spring <NUM> via the number sleeve <NUM>, and clutch plate <NUM>. Rotation of the drive sleeve <NUM> causes the lead screw <NUM> to rotate due to their splined engagement, and the lead screw <NUM> then advances due to its threaded engagement to the housing <NUM>. The number sleeve <NUM> rotation also causes the sliding element <NUM> to traverse axially back to its zero position whereby the zero dose abutment (shown in <FIG>) stops the mechanism.

It is possible to angle the spline teeth on either the drive sleeve <NUM> or the housing <NUM> so that when the zero dose abutment <NUM> stops rotation of the number sleeve <NUM> and hence the drive sleeve <NUM> at the end of the dose and the button <NUM> is released, the spline teeth between the drive sleeve <NUM> and the housing <NUM> rotate the drive sleeve <NUM> backwards by a small amount. This moves the lead screw <NUM> axially back away from the bung and rotates the number sleeve lower <NUM> from the zero dose stop position, helping to prevent possible weepage.

In the present embodiment, the dosage measurement system <NUM> is in the form of a dosage measurement device <NUM> that is attached to a proximal end of the injection device <NUM>.

The dosage measurement device <NUM> comprises a housing <NUM> and a display <NUM> for presenting dosage information. However, it should be recognised that in alternative embodiments (not shown) the display <NUM> is omitted.

As shown in <FIG>, the data measurement device <NUM> also includes one or more processors <NUM>, such as a microprocessor, a Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA) or the like, together with one or more computer readable memory media <NUM>. In the present embodiment, the computer readable memory media <NUM> comprises memory units 64A, 64B, including program memory 64A and main memory 64B, which can store software for execution by the processor <NUM>.

A sensor unit <NUM>, comprising one or more sensors <NUM>, is provided. In this particular example, the sensor <NUM> comprises an optical sensor <NUM>. More specifically, the optical sensor <NUM> is in the form of an optical encoder <NUM>. The optical encoder <NUM> includes a light source 66A, such as a light emitting diode (LED), and a light detector 66B, such as an optical transducer.

The sensor unit <NUM> further comprises a light guide <NUM> in the form of an optical prism <NUM>, which is described in more detail below.

The dosage measurement device <NUM> further comprises an output <NUM>, a power switch <NUM> and a battery <NUM>. Actuation of the power switch <NUM> powers the dosage measurement device <NUM> on and off.

In one embodiment, the power switch <NUM> comprises a button <NUM> on the housing <NUM> of the dosage measurement device <NUM> that is actuated by the user. In another embodiment, the power switch <NUM> is configured to respond to pressure applied to the display <NUM> by powering the dosage measurement device <NUM> on or off. In yet another embodiment (not shown), the power switch <NUM> is actuated when the user actuates the button <NUM>. For instance, the power switch <NUM> may comprise an electrical contact (not shown) on the button <NUM> that makes electrical contact with a second electrical contact (not shown) on a different part of the injection device <NUM>, for example, the housing <NUM> or number sleeve <NUM>, when the button <NUM> is pressed to power the dosage measurement device <NUM> on. When the first and second electrical contacts make contact, a power circuit may be closed such that the dosage measurement device <NUM> is powered on. Advantageously, such an arrangement helps to ensure that the dosage measurement device <NUM> is only operated to measure a dosage being delivered when the button <NUM> is pressed into the housing <NUM> and is thus in its operating position. This may improve accuracy of dosage measurement because otherwise movement of the button <NUM> axially into the housing <NUM>, which moves the sensor unit <NUM> towards the lead screw <NUM> and thus reduces the distance 'D' therebetween, may appear to the sensor unit <NUM> as if the medicament reservoir is being refilled with medicament. Moreover, movement of the button <NUM> axially out of the housing <NUM> when the button <NUM> is released, which moves the sensor unit <NUM> away the lead screw <NUM> and thus increases the distance 'D' therebetween, may appear to the sensor unit <NUM> as if a dosage is being expelled from the injection device <NUM>. However, it should be recognised that other arrangements to help ensure that the dosage measurement device <NUM> is only operated to measure a dosage being delivered when the button <NUM> is in its operating position are also possible. For instance, the processor <NUM> may be configured to only start measuring the dosage dispensed from the injection device <NUM> once it has calculated that the sensor unit <NUM> has moved towards the lead screw <NUM> by a distance D that corresponds to the button <NUM> being actuated by the user. Additionally, or alternatively, if the processor <NUM> calculates that the sensor unit <NUM> has moved relative to the lead screw <NUM> by a distance D in a time period that is consistent with the button <NUM> being released, the processor <NUM> may disregard this dosage measurement or flag it as the button <NUM> being released. In a yet further embodiment, the power switch <NUM> is arranged such that pressing the button <NUM> results in the power switch <NUM> simultaneously being pressed to power on the dosage measurement device <NUM> and/or releasing the button <NUM> results in the power switch <NUM> being released to power off the dosage measurement device <NUM>.

In the present embodiment, the processor <NUM>, computer readable memory media <NUM>, sensor <NUM>, output <NUM> and battery <NUM> are located within the housing <NUM>. However, it should be recognized that in alternative embodiments (not shown) one or more of these components may be located external of the housing <NUM>.

The output <NUM> may be a wireless communications interface for communicating with another device via a wireless network such as wi-fi or Bluetooth®, or an interface for a wired communications link, such as a socket for receiving a Universal Series Bus (USB), mini-USB or micro-USB connector.

<FIG> shows the dosage measurement device <NUM> and the proximal end of the injection device <NUM>.

The button <NUM> includes an aperture <NUM> in its proximal surface 18A, configured such that at least a portion of the dosage measurement device <NUM> can be received in a space <NUM> within the button <NUM>. In the present embodiment, the clutch plate <NUM> comprises an aperture <NUM> and at least a portion of the data measurement device <NUM> extends through the aperture <NUM> in the clutch plate <NUM> to be received in the proximal end of the drive sleeve <NUM>. In more detail, the prism <NUM> extends axially from the housing <NUM> of the dosage measurement device <NUM> such that the prism <NUM> extends through the space <NUM> of the button <NUM> and through the aperture <NUM> of the clutch plate <NUM>. An end 67A of the prism <NUM> is received in the hollow centre of the drive sleeve <NUM>.

The housing <NUM> of the dosage measurement device <NUM> comprises one or more attachment formations <NUM> that are configured to engage with corresponding attachment formations <NUM> on the button <NUM>. In the present embodiment, the attachment formations <NUM> of the dosage measurement device <NUM> comprise projections <NUM> that engage with respective recesses <NUM> in the button <NUM> such that the dosage measurement device <NUM> can be clipped to the button <NUM>. However, it should be recognised that in alternative embodiments (not shown) the attachment formations <NUM> are provided on a different component of the injection device <NUM>.

In some embodiments, the engagement of the attachment formations <NUM>, <NUM> is such that the dosage measurement device <NUM> cannot rotate relative to the button <NUM> when attached thereto.

In embodiments wherein the dosage measurement device <NUM> is to be releasably attachable to the injection device <NUM>, the attachment formations <NUM>, <NUM> may provide a clip-type arrangement that allows for easy removal of the dosage measurement device <NUM>. Such an arrangement may be useful where the dosage measurement device <NUM> is to be used with disposable injection devices <NUM>, since it allows the dosage measurement device <NUM> to be removed from an injection device <NUM> and reused. A removable dosage measurement device <NUM> also affords the user greater flexibility since the user is able to attach and remove the dosage measurement device <NUM> at will.

In some embodiments, the attachment formations <NUM>, <NUM> may be configured to permanently attach the dosage measurement device <NUM> to the injection device <NUM>, for example, using a "snap-fit". Alternatively, the dosage measurement device <NUM> may be permanently attached in other ways, for example, through bonding. Such permanent attachment may be useful where the injection device <NUM> is reusable. The number and/or positions of the attachment formations <NUM>, <NUM> may be configured so that the dosage measurement device <NUM> can only be attached to the injection device <NUM> in one particular orientation relative to the injection device <NUM>.

In some embodiments, the radially-inwardly facing inner surface 21A of the drive sleeve <NUM> comprises one or more detection elements <NUM> that are detectable by the sensor <NUM>. In the present embodiment, the inner surface 21A of the drive sleeve <NUM> comprises a plurality of detection elements <NUM>. The detection elements <NUM> are arranged in an array that subtends circumferentially about the central axis of the drive sleeve <NUM>.

In the particular example shown in <FIG>, twelve detection elements <NUM> are provided. The twelve detection elements <NUM> and the gaps between them have widths selected to provide "edges" <NUM>, to correspond to dose increments up to a maximum dose of, in one particular example, twenty-four units shown on the number sleeve <NUM>.

The detection elements <NUM> comprise a material that has a reflectivity that differs from the material of the inner surface 21A of the drive sleeve <NUM>. In one embodiment, the detection elements <NUM> have a higher reflectivity than the inner surface 21A of the drive sleeve <NUM>. In an alternative embodiment, the detection elements <NUM> have a lower reflectivity than the inner surface 21A of the drive sleeve <NUM>. The detection elements <NUM> may be rectangular. The detection elements <NUM> may be adhered to the inner surface 21A of the drive sleeve <NUM>.

In alternative embodiments (not shown), the detection elements <NUM> comprise apertures in the drive sleeve <NUM>. Alternatively, the detection elements <NUM> may comprise castellations (not shown) that are moulded onto one end of the drive sleeve <NUM>. One end of the drive sleeve <NUM> is provided with castellations that may act as light barriers for light emitted by the light source 66A. The castellations may be formed using a material that has a reflectivity that differs from that of an inner surface 21A of the drive sleeve <NUM>.

In some embodiments, the number sleeve <NUM> is arranged to rotate helically along one direction as a dose is dialled into the injection device <NUM> using the dose dial <NUM> and also to rotate helically in an opposite direction during delivery of a medicament dose by the injection device <NUM>.

The prism <NUM> is configured such that, when the dosage measurement device <NUM> is attached to the injection device <NUM>, light emitted from the light source 66A is transmitted axially along the length of the prism <NUM> and is then reflected off an angled end surface 67A such that the reflected light has a radial component. Thus, the light (depicted by arrow 'L' in <FIG>) is transmitted from the prism <NUM> in a generally radial direction, although the light may still have an axial component such that the light exits the prism <NUM> at an angle between the radial and axial direction. The light transmitted from the prism <NUM> impinges on the inner surface 21A of the drive sleeve <NUM> and/or on one of the detection elements <NUM>, depending on the rotational positon of the drive sleeve <NUM>.

In other words, the light emitted by the light source 66A will be reflected by the inner surface 21A of the drive sleeve <NUM> and/or one of the detection elements <NUM>, depending on the rotational positon of the drive sleeve <NUM>.

In some embodiments, prism <NUM> is configured such that the light is reflected by the principle of total internal reflection. That is, the refractive index is lower in the air than in the material of the prism <NUM> and the incident angle of the light reaching the end surface 67A of the prism <NUM> is less than the critical angle such that the light is entirely reflected. However, it should be recognised that this configuration is not essential to the functioning of the disclosure. For instance, the sensor unit <NUM> would still function if a portion of the light passed through the end surface 67A of the prism <NUM>.

In some embodiments (not shown), the light guide <NUM> may comprise a reflective element (not shown), for example, a mirror, that is angled to reflect the light such that the light is directed radially towards the inner surface 21A of the drive sleeve <NUM>.

In the present embodiment, once the light is reflected by the inner surface 21A of the drive sleeve <NUM> or by one of the detection elements <NUM>, the reflected light will travel back towards the prism <NUM> and will enter the prism <NUM>, travelling in a generally radial direction. The light will then again be reflected from the end surface 67A of the prism <NUM> such that the light travels axially, this time in the proximal direction, through the prism <NUM> until the light reaches the sensor <NUM> wherein the light is detected by the light detector 66B.

Since the reflectivity of the detection elements <NUM> differs from that of the inner surface 21A of the drive sleeve <NUM>, the amount of light detected by the light detector 66B will depend on how much of the light is reflected by a detection element <NUM>. In certain embodiments, the sensor <NUM> may be arranged to emit and/or detect only light with particular polarisation characteristics, in order to mitigate effects of stray light.

<FIG> is a graph showing changes in the intensity of light received by the light detector 66B during programming and delivery of a medicament dose, while <FIG> is a graph showing an output signal that may be generated by the sensor <NUM> of this embodiment.

As noted above, while a dose is being programmed into the injection device <NUM>, during time period t1 in <FIG> and <FIG>, the drive sleeve <NUM> does not rotate relative to the sensor unit <NUM>. Therefore, in this particular embodiment, since the drive sleeve <NUM> does not rotate, the amount of light reflected back towards the light detector 66B should remain substantially constant while the dose is being programmed. The amount of reflected light should also remain substantially constant between the completion of dosage programming and the start of the injection, shown as time period t2 in <FIG>, since the drive sleeve <NUM> and sensor unit <NUM> are not being rotated by a user.

The output of the sensor <NUM>, shown in <FIG>, is therefore substantially constant during time periods t1 and t2. The actual level of the output during time periods t1 and t2 will depend on the proportion of light emitted by the light source 66A that is reflected by a detection element <NUM> and the proportion that is reflected by the inner surface 21A of the drive sleeve <NUM>.

During the delivery of the medicament, shown as time period t3 in <FIG> and <FIG>, the drive sleeve <NUM> rotates relative to the button <NUM>. Therefore, the drive sleeve <NUM> also rotates relative to the sensor unit <NUM> during the delivery of the medicament, the sensor unit <NUM> being attached to the button <NUM>.

During time period t3, the detection elements <NUM> of the number sleeve <NUM> will move across the beam of light transmitted from the prism <NUM> as the drive sleeve <NUM> rotates relative to the sensor unit <NUM>, and the intensity of light received by the light detector 66B will vary accordingly, as shown in <FIG>. In this particular example, the material of the detection elements <NUM> is more reflective than the inner surface 21A of the drive sleeve <NUM>, and so the highest intensity levels shown in <FIG> correspond to positions wherein the highest proportion of the light is reflected by a detection element <NUM>.

The output of the light detector 66B during time period t3 will switch between a high and a low level, based on the received light intensity, as shown in <FIG>. Since the edges of the detection elements <NUM> correspond to increments in the medicament dosage, the processor <NUM> can determine an amount of medication delivered by the injection device based on the number of transitions between the high level and the low level in the output of the sensor <NUM>.

The length of time period t3 will depend on the administered dosage and also on when the medicament delivery is deemed to be complete. When the medicament delivery is complete, the drive sleeve <NUM> will cease to rotate relative to the button <NUM> and the dosage measurement device <NUM>, and the signal from the sensor <NUM> will stay at a substantially constant level.

In some embodiments, the processor <NUM> is arranged to monitor the time period that has elapsed from the last transition or the last pulse in the output of the sensor <NUM>. When the elapsed time period reaches a predetermined threshold t4, the medicament delivery is considered to have been completed and the processor <NUM> proceeds with determining the medicament dose delivered to the user, based on the number of detected transitions in the output of the sensor <NUM> during time period t3. In the particular example shown in <FIG> and <FIG>, there are eight transitions. Since the transitions correspond to the edges of the detection elements <NUM> which, in turn, correspond to the dosage increments in this particular embodiment, the determined medicament dose is <NUM> units.

The processor <NUM> then stores the determined medicament dose in main memory 64B. The processor <NUM> may also store time stamp information, to provide a log recording delivery of medicament to the user. The processor <NUM> may then power down the dosage measurement device <NUM>, in order to conserve battery power.

When the dosage measurement device <NUM> is powered on again, by a user activating the power switch <NUM>, the processor <NUM> may control the display <NUM> to show the determined medicament dose information, to aid the memory of the user. Optionally, the processor <NUM> may monitor an elapsed time since the determined medicament dose was delivered and control the display to show that elapsed time information too. For example, the processor <NUM> may cause the display <NUM> to switch periodically between displaying the determined medicament dosage information and the elapsed time.

The processor <NUM> may also transmit the determined medicament dosage and, where determined, the time stamp information to another device, such as a computer (not shown). As noted above, the output <NUM> may be configured to transmit the information using a wireless communications link. Alternatively, the dosage measurement device <NUM> may be connected to the computer (not shown) using a wired connection (not shown) to allow the information to be uploaded to the computer. The processor <NUM> may be configured to transmit the information to the computer periodically. In some embodiments, the display <NUM> may be omitted. In some embodiments, the dosage measurement system <NUM> may be used to monitor compliance with a particular dosage regime.

The specific embodiments described in detail above are intended merely as examples of how the present disclosure may be implemented. Many variations in the configuration of the dosage measurement device <NUM> and/or the injection device <NUM> may be conceived. For example, it is not necessary that the detection elements <NUM> provided on the drive sleeve <NUM> are in the form of reflective material, nor is it necessary for the widths of the detection elements <NUM> and the gaps between them to correspond precisely to individual dosage increments, as in the above embodiment.

While the above described embodiment utilises an optical sensor <NUM>, other types of sensors may be used as well as, or instead of, optical sensors. For example, the sensor may include a magnetic sensor, such as a Hall effect sensor. In such an example, the detection elements may comprise one or more magnets may be mounted on the drive sleeve <NUM>, so that rotation of the drive sleeve <NUM> relative to the sensor unit <NUM> results in a varying magnetic field. In another example, a capacitive sensor may be used, wherein the detection elements may comprise elements provided on the drive sleeve that affect the capacitance between two plates provided in the sensor unit. In other examples, mechanical sensors, with mechanical switches and/or tracks, may be used to detect the relative movement of the drive sleeve <NUM> relative to the sensor unit. While the embodiment shown in <FIG> includes only one sensor, other embodiments may be devised in which the sensor arrangement includes multiple sensors of one or more types.

Referring now to <FIG>, a medicament delivery system according to a second embodiment of the disclosure is shown. The medicament delivery system is similar to the measurement delivery system described above in reference to the first embodiment of the disclosure, with like features retaining the same reference numerals. The medicament delivery system comprises a medicament delivery device <NUM> and a dosage measurement system <NUM>.

The medicament delivery device <NUM> is in the form of an injection device <NUM>. The dosage measurement system <NUM> comprises a dosage measurement device <NUM> that is attached to a proximal end of the injection device <NUM>. The dosage measurement device <NUM> comprises a housing <NUM>, a processor (not shown), computer readable memory media (not shown), a power switch <NUM>, a battery (not shown), and an output (not shown).

A difference between the dosage measurement system <NUM> of the first embodiment and the dosage measurement system <NUM> of the second embodiment is that the sensor unit <NUM> is omitted and is replaced by an alternative sensor unit <NUM>. The sensor unit <NUM> comprises a sensor <NUM>, which in the present embodiment is an optical sensor <NUM> having a light source (not shown) and a light detector (not shown). However, the light guide <NUM> of the sensor unit <NUM> of the first embodiment is omitted and instead the sensor <NUM> is located on a support member <NUM>.

The support member <NUM> extends from the housing <NUM> such that when the dosage measurement device <NUM> is attached to the injection device <NUM>, the support member <NUM> extends axially in the distal direction such that an end 87A of the support member <NUM> is located within the drive sleeve <NUM>. The sensor <NUM> is mounted on, or proximate to, said 87A such that the sensor <NUM> is directed towards the inner surface 21A of the drive sleeve <NUM> and the detection elements <NUM> located thereon. More specifically, the sensor <NUM> is arranged such that light emitted by the light source (not shown) irradiates the inner surface 21A of the drive sleeve and/or one of the detection elements <NUM>, depending on the rotational positon of the drive sleeve <NUM>, and is reflected thereby. The reflected light travels back towards the sensor <NUM> and is detected by the light detector (not shown).

The sensor <NUM> is connected to the processor (not shown) by one or more conductive elements <NUM>, for example, tracks or wires, which extend from the sensor <NUM> to the housing <NUM>. The conductive elements <NUM> may be adhered to or embedded in the support member <NUM>.

As before, since the reflectivity of the detection elements <NUM> differs from that of the inner surface 21A of the drive sleeve <NUM>, the amount of light detected by the light detector (not shown) of the sensor <NUM> will depend on how much of the light is reflected by a detection element <NUM> and thus will depend on the rotational position of the drive sleeve <NUM>. Therefore, the processor (not shown) is able to determine a dosage dispensed from the injection device <NUM> based on the output of the sensor unit <NUM>, which measures the rotation of the drive sleeve <NUM>.

In the above described embodiments, the button <NUM> includes an aperture <NUM> to allow for the dosage measurement device <NUM> to be inserted into the space <NUM> of the button <NUM>. However, it should be recognised that in alternative embodiments (not shown) the aperture <NUM> is omitted. For example, the dosage measurement system <NUM> may be integrated into the injection device <NUM> such that the dosage measurement system <NUM> is permanently received in the space <NUM>.

In other embodiments, the dosage measurement system <NUM> is removably attached or permanently fixed to a part of the injection device <NUM> other than the button <NUM>, for instance, the housing <NUM>.

In the above described embodiments the attachment formations <NUM>, <NUM> are in the form of projections <NUM> on the housing <NUM> of the dosage measurement device <NUM> that are received in respective recesses <NUM> in the button <NUM>. However, it should be recognised that other types of engaging attachment formations or attachment methods may be used. In one alternative embodiment (not shown), the attachment formations are in the form of projections <NUM> on the button <NUM> that are received in respective recesses in the housing <NUM> of the dosage measurement device <NUM>. Alternatively, the dosage measurement system <NUM> may be bonded to the injection device <NUM>. In one embodiment (not shown), the dosage measurement system <NUM> is permanently integrated with the injection device <NUM>. For instance, the dosage measurement system <NUM> may be integrated with the injection device <NUM> during assembly of the injection device <NUM>. In one embodiment, the housing <NUM> of the dosage measurement system <NUM> is omitted and instead one or more components of the injection device <NUM>, for example, the button <NUM>, drive sleeve <NUM> and/or housing <NUM>, contain the components of the dosage measurement system <NUM>.

In the above described embodiments, the detection elements <NUM> are provided on the inner surface 21A of the drive sleeve <NUM> and the sensor <NUM>, <NUM> is directed towards the inner surface 21A to detect the detection elements <NUM>. In alternative embodiments (not shown), the detection elements may instead be provided on the lead screw <NUM>, for example, on a proximally-facing end surface of the lead screw <NUM>, and the sensor may be directed towards the detection elements. The sensor <NUM>, <NUM> detects rotation of the lead screw <NUM> and the processor determines the dosage dispensed from the medicament reservoir based on the measured rotation of the lead screw.

Referring now to <FIG>, a schematic view of a medicament delivery system according to a third embodiment of the disclosure is shown. The medicament delivery system comprises a medicament delivery device <NUM> and a dosage measurement system <NUM>.

The medicament delivery device <NUM> is in the form of an injection device <NUM>. The medicament delivery device <NUM> comprises a housing <NUM> that contains a medicament reservoir (not shown), plunger (not shown), lead screw <NUM>, drive sleeve <NUM> and drive unit <NUM>.

The drive unit <NUM> is configured to rotate the drive sleeve <NUM> relative to the housing <NUM>. The drive sleeve <NUM> engages with the lead screw <NUM> such that rotation of the drive sleeve <NUM> causes rotation of the lead screw <NUM>. The lead screw <NUM> and drive sleeve <NUM> may engage via, for example, a threaded interface (not shown).

The lead screw <NUM> also engages with the housing <NUM> such that rotation of the lead screw <NUM> relative to the housing <NUM> causes axial displacement of the lead screw <NUM> relative to the housing <NUM> such that the plunger is moved within the medicament reservoir to dispense medicament therefrom. Thus, operation of the drive unit <NUM> causes rotation of the drive sleeve <NUM> such that the lead screw <NUM> is moved axially relative to the housing <NUM> to dispense medicament from the medicament reservoir.

The drive unit <NUM> comprises a biasing member <NUM> and a locking mechanism <NUM> that is coupled to an actuator <NUM>. The biasing member <NUM> is configured to bias the drive sleeve <NUM> to rotate relative to the housing <NUM>. The biasing member <NUM> is mounted to an axle 116A such that a first end of the biasing member <NUM> is connected to the axle 116A. A second end of the biasing member <NUM> is coupled to the drive sleeve <NUM> by a connecting member <NUM>. In the present embodiment, the connecting member <NUM> is fixed relative to the second end of the biasing member <NUM> and is received in a groove (not shown) in the inside surface of the drive sleeve <NUM> such that the connecting member <NUM> is rotationally fixed relative to the drive sleeve <NUM>.

The locking mechanism <NUM> initially prevents the biasing member <NUM> from rotating the drive sleeve <NUM> relative to the housing <NUM>. The locking mechanism <NUM> is coupled to the actuator <NUM> such that the actuator <NUM> is operable to release the drive sleeve <NUM>. The locking mechanism <NUM> may comprise, for example, a locking pin (not shown) that initially engages the second end of the biasing member <NUM> to prevent movement of the biasing member <NUM> relative to the housing <NUM>. Actuation of the actuator <NUM> by the user may move the locking pin out of engagement with the second end of the biasing member <NUM>. However, the locking mechanism may have a different arrangement, for example, in one embodiment (not shown) comprising an electromagnetic latch that is operated to release the biasing member.

To operate the medicament delivery device <NUM>, the user presses the actuator <NUM> such that the locking mechanism <NUM> releases the biasing member <NUM> and thus the drive sleeve <NUM> is rotated relative to the housing <NUM>. This causes the lead screw <NUM> to be rotated relative to the housing <NUM> and moved axially relative to the housing <NUM> such that the plunger (not shown) is moved axially within the medicament reservoir and thus medicament is dispensed therefrom. The medicament reservoir may be fluidly connected to, for example, a needle, for delivery of the medicament to a patient.

The dosage measurement system <NUM> comprises a sensor unit <NUM> having a sensor <NUM> and a processor (not shown). In the present embodiment the sensor <NUM> is an optical sensor <NUM> having a light source (not shown) and a light detector (not shown). In the present embodiment, the sensor unit <NUM> is mounted to the axle 116A that supports the biasing member <NUM>. However, it should be recognised that in alternative embodiments (not shown) the sensor unit <NUM> is mounted to a different part of the medicament delivery device <NUM>, for example, the housing <NUM>.

The sensor <NUM> is directed towards the inner surface 114A of the drive sleeve <NUM> such that the sensor <NUM> detects the presence of detection elements <NUM> mounted on the inner surface 114A. More specifically, the sensor <NUM> is arranged such that light emitted by the light source (not shown) irradiates the inner surface 114A of the drive sleeve <NUM> and/or one of the detection elements <NUM>, depending on the rotational positon of the drive sleeve <NUM>, and is reflected thereby. The reflected light travels back towards the sensor <NUM> and is detected by the light detector (not shown). In some embodiments (not shown), the sensor unit <NUM> further comprises a transmission member (not shown), such as a light guide, that transmits a signal from the sensor <NUM> towards the inner surface 114A of the drive sleeve <NUM>.

The sensor <NUM> is connected to the processor (not shown). As described above in reference to the first and second embodiments, since the reflectivity of the detection elements <NUM> differs from that of the inner surface 114A of the drive sleeve <NUM>, the amount of light detected by the light detector (not shown) of the sensor <NUM> will depend on how much of the light is reflected by a detection element <NUM> and thus will depend on the rotational position of the drive sleeve <NUM>. Therefore, the processor (not shown) is able to determine a dosage dispensed from the injection device <NUM> based on the output of the sensor unit <NUM>, which measures the rotation of the drive sleeve <NUM>.

In an alternative embodiment (not shown), the sensor <NUM> is instead directed towards an end surface 113A of the lead screw <NUM> such that such that the sensor <NUM> detects the presence of detection elements (not shown) provided at the end surface 113A. In such an alternative embodiment, the sensor <NUM> may be arranged such that light emitted by the light source (not shown) irradiates the inner surface 113A of the lead screw <NUM> and/or one of the detection elements, depending on the rotational positon of the lead screw <NUM>, and is reflected thereby. The reflected light travels back towards the sensor <NUM> and is detected by the light detector (not shown). Since the reflectivity of the detection elements differs from that of the end surface 113A of the lead screw <NUM>, the amount of light detected by the light detector (not shown) of the sensor <NUM> will depend on how much of the light is reflected by a detection element and thus will depend on the rotational position of the lead screw <NUM>. Therefore, the processor (not shown) is able to determine a dosage dispensed from the injection device <NUM> based on the output of the sensor unit <NUM>, which measures the rotation of the lead screw <NUM>.

In the present embodiment, the biasing member <NUM> is in the form of a torsion spring <NUM>. However, it should be recognised that other types of biasing member are intended to fall within the scope of the disclosure. In yet further embodiments (not shown), the biasing member is omitted and instead the drive unit comprises an electric motor that is operated to rotate the drive sleeve and thus dispense the medicament from the medicament reservoir. Alternatively, the drive unit may comprise a component that is manually rotated by the user to rotate the drive sleeve to dispense the medicament.

In some embodiments (not shown), the dosage measurement system <NUM>, <NUM>, <NUM> comprises a first part and a second part that is attachable to the first part. The second part may be releasably attachable to the first part. The first part of the dosage measurement device <NUM>, <NUM>, <NUM> may comprise one or more attachment formations (not shown) that are configured to engage with corresponding attachment formations (not shown) on the second part. The attachment formations of the first part or second part may comprise projections that engage with respective recesses in the other of the first and second part such that the second part can be clipped to the first part. However, it should be recognised that in alternative embodiments (not shown) the second part is attached to the first part via a different arrangement, for example, being received in a recess in the first part such that the first and second parts are held together via friction. The first and second parts may comprise engaging elements, for example, rails that engage with grooves, which ensure a particular rotational orientation of the first part relative to the second part when the second part is attached to the first part.

The dosage measurement system <NUM>, <NUM>, <NUM> comprising first and second parts allows for the first part to be attached to, or integrated with, the injection device <NUM>, <NUM> and for the second part to be removably attached to the first part. Therefore, the injection device <NUM>, <NUM> and the first part can be disposed of and the second part can be reused by removing it from the first part and attaching it to the first part of a different injection device <NUM>, <NUM>. One or more of the battery, user interface, processor and sensor can be incorporated into the second part. Thus, these components, which are relatively expensive, can be reused with further injection devices by attaching the second part to the first part of said further injection devices. In one embodiment, the first part comprises a transmission member, for example, a light guide, that is fixed to the injection device <NUM>, <NUM>. The second part comprises a battery, processor and a sensor. The second part attaches to the first part such that the transmission member and sensor form a sensor unit, wherein the transmission member is able to transmit a signal emitted by the sensor towards the detection elements and also to transmit the reflected signal back towards the sensor. Once medicament delivery is complete, the second part is detached from the first part and the first part together with the medicament delivery device is disposed of. In another embodiment (not shown), the first part comprises a support member that is fixed to the injection device <NUM>, <NUM> and a sensor that is provided on the support member. The second part comprises a battery and processor. The second part attaches to the first part such that the sensor is coupled to the processor and thus the processor is able to determine a dosage dispensed from the medicament reservoir based on the measured rotation of said at least one of the drive sleeve and lead screw. Once medicament delivery is complete, the second part is detached from the first part and the first part together with the medicament delivery device is disposed of.

In the above described embodiments the medicament delivery device <NUM>, <NUM> comprises an injection device. The injection device may comprise a pen injection device and may comprise an autoinjector. However, it should be recognised that the medicament delivery system may comprise a different type of medicament delivery device. For example, the medicament delivery device may comprise a patch device that is attached to the injection site of a patient. The medicament delivery device may be a pump device.

While the embodiments above have been described in relation to collecting data from an insulin injector pen, it is noted that embodiments of the disclosure may be used for other purposes, such as monitoring of injections of other medicaments.

The term "medicament delivery device", which is also referred to hereinafter as "drug delivery device", shall encompass any type of device or system configured to dispense a drug into a human or animal body. Without limitation, a drug or medicament delivery device may be an injection device (e.g., syringe, pen injector, auto injector, large-volume device, pump, perfusion system, or other device configured for intraocular, subcutaneous, intramuscular, or intravascular delivery), skin patch (e.g., osmotic, chemical, micro-needle), inhaler (e.g., nasal or pulmonary), implantable (e.g., coated stent, capsule), or feeding systems for the gastro-intestinal tract.

Exemplary insulin analogues 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, wherein proline in position B28 is replaced by Asp, Lys, Leu, Val orAla and wherein in position B29 Lys may be replaced by Pro; Ala(B26) human insulin; Des(B28-B30) human insulin; Des(B27) human insulin and Des(B30) human insulin.

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-(w-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyhepta¬decanoyl) human insulin. Exemplary GLP-<NUM>, GLP-<NUM> analogues and GLP-<NUM> receptor agonists are, for example: Lixisenatide / AVE0010 / ZP10 / Lyxumia, Exenatide / Exendin-<NUM> / Byetta / Bydureon / ITCA <NUM> / AC-<NUM> (a <NUM> amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide / Victoza, Semaglutide, Taspoglutide, Syncria /Albiglutide, Dulaglutide, rExendin-<NUM>, CJC-<NUM>-PC, PB-<NUM>, TTP-<NUM>, Langlenatide / HM-11260C, CM-<NUM>, GLP-<NUM> Eligen, ORMD-<NUM>, NN-<NUM>, NN-<NUM>, NN-<NUM>, Nodexen, Viador-GLP-<NUM>, CVX-<NUM>, ZYOG-<NUM>, ZYD-<NUM>, GSK-<NUM>, DA-<NUM>, MAR-<NUM>, MAR709, ZP-<NUM>, ZP-<NUM>, TT-<NUM>, BHM-<NUM>. MOD-<NUM>, CAM-<NUM>, DA-<NUM>, ARI-<NUM>, ARI-<NUM>, Exenatide-XTEN and Glucagon-Xten.

Antibody fragments that are useful in the present disclosure include, for example, Fab fragments, F(ab')<NUM> fragments, scFv (single-chain Fv) fragments, linear antibodies, monospecific or multispecific antibody fragments such as bispecific, trispecific, and multispecific antibodies (e.g., diabodies, triabodies, tetrabodies), minibodies, chelating recombinant antibodies, tribodies or bibodies, intrabodies, nanobodies, small modular immunopharmaceuticals (SMIP), binding-domain immunoglobulin fusion proteins, camelized antibodies, and VHH containing antibodies.

Claim 1:
A medicament delivery device (<NUM>, <NUM>) comprising:
a medicament reservoir (<NUM>);
a lead screw (<NUM>, <NUM>);
a drive sleeve (<NUM>; <NUM>) that is rotatable to axially displace the lead screw (<NUM>, <NUM>) relative to the drive sleeve (<NUM>, <NUM>) to dispense medicament from the medicament reservoir (<NUM>), the lead screw being rotationally coupled to the drive sleeve; and
a dosage measurement system (<NUM>, <NUM>, <NUM>), comprising:
a sensor unit (<NUM>, <NUM>, <NUM>) configured to measure rotation of at least one of the drive sleeve (<NUM>, <NUM>) and lead screw (<NUM>, <NUM>), wherein the sensor unit (<NUM>, <NUM>, <NUM>) is configured to transmit a light signal that travels within a hollow centre provided in the drive sleeve (<NUM>, <NUM>) and is reflected from said at least one of the drive sleeve (<NUM>, <NUM>) and lead screw (<NUM>, <NUM>); and,
a processor (<NUM>) configured to determine a dosage dispensed from the medicament reservoir (<NUM>) based on the measured rotation of said at least one of the drive sleeve (<NUM>, <NUM>) and lead screw (<NUM>, <NUM>).