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.

Injection devices (i.e. devices capable of delivering medicaments from a medication container) typically fall into two categories - manual devices and auto-injectors.

In a manual device - the user must provide the mechanical energy to drive the fluid through the needle. This is typically done by some form of button and/or the needle cover (sleeve triggered devices)/ plunger that has to be continuously pressed by the user during the injection. There are numerous disadvantages for the user from this approach. If the user stops pressing the button / plunger, then the injection will also stop. This means that the user can deliver an underdose if the device is not used properly (i.e. the plunger is not fully pressed to its end position). Injection forces may be too high for the user, in particular if the patient is elderly or has dexterity problems.

The extension of the button/plunger may be too great. Thus it can be inconvenient for the user to reach a fully extended button. The combination of injection force and button extension can cause trembling / shaking of the hand which in turn increases discomfort as the inserted needle moves.

Auto-injector devices aim to make self-administration of injected therapies easier for patients. Current therapies delivered by means of self-administered injections include drugs for diabetes (both insulin and newer GLP-<NUM> class drugs), migraine, allergies, hormone therapies, anticoagulants etc. Auto-injector devices can be used to deliver a single dose of a particular life-saving drug. For example they are often prescribed to people who are at risk for anaphylaxis. They are also often used in the military to protect personnel from chemical warfare agents. Alternatively, auto-injectors are used to administer medicaments according to a prescribed therapeutic schedule for people suffering from Multiple Sclerosis, Rheumatroid Arthritis, Anemia, e.g..

Auto-injectors are devices which completely or partially replace activities involved in parenteral drug delivery from standard syringes. These activities may include removal of a protective syringe cap, insertion of a needle into a patient's skin, injection of the medicament, removal of the needle, shielding of the needle and preventing reuse of the device. This overcomes many of the disadvantages of manual devices. Forces required of the user / button extension, hand-shaking and the likelihood of delivering an incomplete dose are reduced. Triggering may be performed by numerous means, for example a trigger button or the action of the needle reaching its injection depth. In some devices the energy to deliver the fluid is provided by a spring.

Auto-injectors may be disposable or single use devices which may only be used to deliver one dose of medicament and which have to be disposed of after use. Other types of auto-injectors may be reusable. Usually they are arranged to allow a user to load and unload a standard syringe. The reusable auto-injector may be used to perform multiple parenteral drug deliveries, whereas the syringe is disposed after having been spent and unloaded from the auto-injector. The syringe may be packaged with additional parts to provide additional functionality.

In a typical scenario a disease can be treated by patients themselves by injection of medicament doses using an auto-injector, for example on a daily, weekly, bi-weekly, or monthly basis.

The correct administration of drugs and its termination is important for the safety and efficacy of the drug (pharmacovigilance). Failures in administration through the user can be minimized by monitoring of the injection device and the application time. Typical patient failures are:.

The invention describes a re-usable add-on device suitable for use with one shot auto-injectors and which may record the injection history, monitor the dose administration and aid the patient in performing the injection correctly and on time.

<CIT> and <CIT> both disclose a supplemental device comprising a housing that attaches to an injection device, and includes a locating channel that receives a locating rib of the injection device to ensure correct positioning of the supplemental device on the injection device. The supplemental device further comprises protuberances on arms which locate within indents of the injection device.

<CIT> discloses a monitoring device comprising a housing portion that attaches to a drug delivery device, and includes coupling means for engaging corresponding coupling means on the drug delivery device.

<CIT> discloses a supplementary device comprising a housing for attachment to an injection device and includes a rib receiving recess that receives a rib protruding from the injection device to aid in the correct alignment of the supplementary device and injection device. The supplemental device of further comprises engaging arms having protuberances which locate within indents of the injection device and the engaging arms comprise respective actuating sections formed integrally with the protuberances and to rotate the engaging arms to move the protuberances outwardly to allow the supplementary device to be removed from the injection device.

<CIT> discloses a supplementary device comprising a body for attachment to an injection device and includes protuberances that locate in indents of the injection device to retain the supplementary device relative to the injection device. Also disclosed is a collar section integral with the protuberances and deformable to urge the protuberances out of the indents.

A first aspect of the invention provides a supplementary device configured to be releasably attached to a drug delivery device, the supplementary device comprising a housing having a channel configured to slidably receive the drug delivery device, a first alignment feature to ensure a specific alignment of the supplementary device relative to the drug delivery device and restrict rotational movement of the supplementary device around a drug delivery device, a second alignment feature to prevent sliding movement of the supplementary device relative to the delivery device once attached thereto, wherein the second alignment feature comprises a moveable securing member biased towards the drug delivery device, and a release member operable to be urged against the securing member to move between a rest position in which the securing member is permitted to engage the drug delivery device, and a release position in which the securing member is moved out of engagement with the drug delivery device.

The first alignment feature may be configured to engage with a cooperating feature of the drug delivery device and may permit sliding movement of the drug delivery device within the channel.

The first alignment feature may comprise a slot formed in the housing which is configured to receive a projection formed on the drug delivery device.

The securing member may comprise a boss configured to be received in a recess formed in the drug delivery device.

The supplementary device may further comprise a biasing member configured to bias the securing member towards the drug delivery device.

The securing member may be integrally formed with the housing.

The release member may comprise a release lever rotatable between a rest position in which the securing member is permitted to engage the drug delivery device, and a release position in which the securing member is moved out of engagement with the drug delivery device.

The release lever may comprise a shaft and a radial projection from the shaft configured to engage with the securing member.

The supplementary device may further comprise a locking mechanism including an actuator moveable between a locked position and an unlocked position, wherein the locking mechanism may be operable to releasably lock the supplementary device to a drug delivery device.

The actuator may include a visual indicator to indicate when the actuator is in one of the locked or unlocked positions.

The actuator may be configured to render the supplementary device operable when in the locked position and inoperable when in the unlocked position.

The actuator may be configured to trigger a function of the supplementary device when moved to the locked and/or unlocked position.

The supplementary device may further comprise a third alignment feature comprising opposing flat reference surfaces formed on the inner wall of the channel of the housing. The flat reference surfaces may be equally spaced from a centre line extending through the supplementary device. Each reference surface may be angled by the same degree away either side of a vertical line extending through the supplementary device.

In one embodiment, the release member is operable to be urged against the securing member to move the securing member out of engagement with the drug delivery device. The release member may be a separate component to the securing member.

The release member may be moveable relative to the securing member to move the securing member out of engagement with the drug delivery device. In one embodiment, the release member is rotatable relative to the securing member to move the securing member out of engagement with the drug delivery device. In another embodiment, the release member is slidable relative to the securing member to move the securing member out of engagement with the drug delivery device. The release member may be rotatable and slidable relative to the securing member to move the securing member out of engagement with the drug delivery device. In one embodiment, the release member is separate to the securing member.

In one embodiment, the drug delivery device comprises corresponding alignment features configured to respectively cooperate with the first and second alignment features of the supplementary device.

A second aspect of the invention provides a system comprising the supplementary device as described above and a drug delivery device, wherein the drug delivery device comprises corresponding alignment features configured to respectively cooperate with the first and second alignment features of the supplementary device.

The drug delivery device may comprise a reservoir of liquid medicament.

The supplementary device may comprise a non-contact sensor configured to output signals indicative of the position of a moveable component within the drug delivery device, and a processor configured to receive the signals output from the non-contact sensor and to determine based on the signals whether the drug delivery device is in a pre-activation state or a post-activation state.

This may allow the supplementary device to notify a user regarding the operational state of the device and the supplementary device may do this more clearly and effectively than the drug delivery device is able to do. Using a non-contact sensor allows the supplementary device to monitor the drug delivery device without any increase in friction on the mechanical components of the drug delivery device. The moveable component within the drug delivery device is already present in the design of the mechanism of the drug delivery device and therefore no significant modifications to the way in which this mechanism operates are required to implement the invention. Thus the increases in the complexity of manufacture of the drug delivery device are minor.

The non-contact sensor may be a capacitive sensor. Components of the capacitive sensor may be arranged within the supplementary device such that the attached drug delivery device forms at least a part of a dielectric layer of the capacitive sensor. The capacitive sensor may comprise opposing sets of at least one electrically conductive plate.

The non-contact sensor may be a Hall sensor configured to measure a magnetic field produced by the moveable component within the drug delivery device. The device may additionally include an AMR (Anisotropic magnetoresistance) sensor.

Upon determining that the drug delivery device has changed from a pre-activation state to a post-activation state, the processor may be configured to cause an indication to be output which informs a user regarding a "dwell time" of the drug delivery device. The supplementary device may further comprise a display unit. Causing an indication to be output may comprises causing one or more graphical elements to be displayed on the display unit, the graphical elements communicating a progress of the "dwell time". The capacitive sensor may detect movement of a plunger spring to enable an entire drug delivery process, such as an injection process, to be monitored. A hall sensor may be provided to detect stalling of the delivery mechanism, such as the spring. The capacitive sensor may be able to detect an end-stop position of the drug delivery mechanism.

This may be advantageous as it may assist the user in using the drug delivery device correctly and in particular reduces the risk of the user performing an underdose by removing the needle of the drug delivery device too soon after injection of the medicament.

The supplementary device may further comprise at least one memory. The processor may be configured to cause information relating to a last performed injection operation to be stored in the memory upon determining that the drug delivery device has changed from a pre-activation state to a post-activation state. The information may comprise at least a time stamp associated with the last performed injection operation. The information may further comprise a medicament dose amount and/or a medicament type.

Storing this information electronically may allow it to be communicated easily to other devices and people, such as the user's doctor. It may also allow the user to have greater oversight and control of their medication regime.

The processor may have access to or may be configured to calculate a time of next injection and may be further configured to produce a reminder signal when the time of next injection occurs.

The processor may have access to or may be configured to calculate a medical regimen associated with a user of the supplementary device. The medical regimen may comprise at least a series of times at which an injection operation is due to be performed. The processor may be configured to cause a reminder signal to be produced when a next injection operation is due according to the medical regimen.

Producing an automatic reminder signal may be advantageous for ensuring user compliance with their medical regimen, particularly where the user's medical regimen might mean there are many days between doses.

The supplementary device may further comprise a wireless unit for transmitting data to one or more external devices. The supplementary device may be further configured to send the reminder signal to the one or more external devices. For example, the stored information could be transmitted to the user's computer or smart phone wirelessly, for example over a Bluetooth ® connection.

The supplementary device may further comprise an optical sensor configured to read information visible on a housing of the injection device, the information identifying a medicament contained in the drug delivery device. This may be advantageous as it may allow the supplementary device to check the type and concentration of the medication in the drug delivery device before injection. The supplementary device may warn the user if the type or concentration of medication in the attached drug delivery device is incorrect.

The supplementary device may further comprise an outer needle cap sensor configured to output signals indicative of whether an outer needle cap is attached to the drug delivery device. The processor may be configured to receive the signals output from the outer needle cap sensor and to determine whether the outer needle cap is attached or not attached. If the processor determines that the drug delivery device is in a post-activation state and that the outer needle cap is not attached then, after a predetermined time, the processor may be configured to cause an alarm signal to be output. Causing an alarm signal to be output may comprise causing the supplementary device to emit one or more sounds and/or to display one or more indications on a display unit of the supplementary device.

This feature may help to avoid needle clogging which can occur if the drug delivery device is stored without the outer needle cap attached. The signal indicative of whether the outer needle cap is attached may also be sent to a user's smart phone or other portable device, so that they can be notified of the problem, even if they are not located near to the drug delivery device. The removal of the outer needle cap can also be used as a trigger. The removal of the outer needle cap may trigger the supplementary device to power on and to begin its monitoring processes. Therefore the user does not need to perform any additional operations to begin using the supplementary device. This greatly simplifies use of the supplementary device for a user. Similarly, the replacement of the outer needle cap may trigger the supplementary device to turn off, thus saving power.

The drug delivery device may be a powered auto-injector.

Another aspect of the invention may provide a system comprising the supplementary device as defined above and a drug delivery device. The drug delivery device may be a powered auto-injector. A dispensing mechanism of the powered auto-injector may be powered by a pre-compressed spring.

The drug delivery device may include a cartridge, syringe or other reservoir of liquid medicament.

Embodiments of the present invention will now be described, by way of example only, with reference to the following figures, in which:.

In the following, embodiments of the present invention will be described with reference to an auto-injector. The present invention is however not limited to such application and may equally well be deployed with injection devices that eject other medicaments, or with other types of drug delivery devices, such as syringes, pre-filled syringes, needleless injectors and inhalers.

An injection device <NUM> according to embodiments will now be described with reference to <FIG>. In some embodiments, the injection device <NUM> is a single use auto-injector <NUM>. The auto-injector <NUM> has a proximal end P and a distal end D. The proximal end P is directed towards the injection site of a patient during an injection while the distal end D is directed away from the injection site.

The auto-injector <NUM> comprises a body <NUM> and a cap <NUM> (also referred to herein as the outer needle cap or ONC <NUM>). The body <NUM> comprises an outer housing <NUM>. The outer housing <NUM> is an elongate tube. The outer housing <NUM> includes a cartridge holder or syringe holder (not shown) which supports a cartridge or syringe <NUM> containing liquid medicament <NUM>. Hereafter the description shall refer to a cartridge <NUM>, which is supported by a cartridge holder (not shown). The cartridge <NUM> is shown in broken lines in <FIG>.

The outer housing <NUM> also houses a dispense mechanism (not shown) for causing dispensing of the medicament <NUM> during injection.

A hollow needle <NUM> fluidly communicates with an interior volume of the cartridge <NUM> and serves as a conduit for liquid medicament <NUM> during injection. The needle <NUM> and the cartridge <NUM> are in a fixed position relative to each other and to the body <NUM>. A stopper, plunger, piston or bung <NUM> is moveable within the cartridge <NUM> to as to expel medicament contained within the cartridge <NUM> through the needle <NUM> under action of the dispense mechanism.

The dispense mechanism is mechanically coupled to the piston <NUM> of cartridge <NUM>. The dispense mechanism is configured to move the piston axially along the cartridge <NUM> in a proximal direction to dispense medicament <NUM> through the needle <NUM>. The dispense mechanism includes components that cooperate to apply a force to the piston <NUM> in response to an actuation input provided by a user. Here, the actuation input that triggers application of a force to the piston <NUM> is received by way of a dose dispense button <NUM> that is located at the distal end of the auto-injector <NUM>. The dispense mechanism is mechanically coupled to the dispense button <NUM>. In alternative configurations of auto-injector envisaged within the scope of the present disclosure, alternative actuation inputs may be provided to trigger the dispense mechanism. For example, the dispense mechanism may include a sleeve-triggered actuator.

The body <NUM> also comprises a cap support <NUM> at the proximal end of the outer housing <NUM>. The cap support is concentric with the outer housing <NUM> and may have a smaller diameter. The cap support <NUM> extends from the proximal end of the housing <NUM>. The ONC <NUM> is received over the cap support <NUM> to close the proximal end of the body <NUM> and to cover the needle <NUM>. The ONC <NUM> comprises a cylindrical wall 22a and an end wall 22b. With the ONC <NUM> located on the body <NUM>, as shown in <FIG>, an internal surface of the cylindrical wall 22a abuts an external surface of the cap support <NUM> in tightly abutting relation so that the ONC <NUM> is retained thereon in an attached position.

To inject the medicament <NUM>, the ONC <NUM> is removed from the device <NUM> by the user, resulting in the arrangement shown in <FIG>. Next, the proximal end of the auto-injector <NUM> is placed against an injection site of a patient, which may be the user or another person. The user then actuates the dispense button <NUM>. This causes the dispense mechanism to force the piston <NUM> to expel medicament from the cartridge <NUM> through the needle <NUM> into the injection site of the patient.

The cartridge <NUM> is transparent and a window <NUM> is provided in the housing <NUM> coincident with the cartridge <NUM> so that the medicament <NUM> contained within the cartridge <NUM> is visible. A user of the auto-injector is thereby able by inspection to determine whether the entire quantity of medicament <NUM> has been ejected from the cartridge <NUM> during the injection.

A label is provided on the housing <NUM>. The label includes information <NUM> about the medicament included within the injection device <NUM>, including information identifying the medicament. The information <NUM> identifying the medicament may be in the form of text. The information <NUM> identifying the medicament may also be in the form of a colour. The information <NUM> identifying the medicament may also be encoded into a barcode, QR code or the like. The information <NUM> identifying the medicament may also be in the form of a black and white pattern, a colour pattern or shading.

<FIG> is a schematic illustration of an embodiment of a supplementary device <NUM> to be releasably attached to injection device <NUM> of <FIG>. The features for accurately securing and locating the supplementary device <NUM> of the invention in place on the injection device <NUM> are omitted from <FIG> for ease of illustration of the other functional features of the supplementary device <NUM>. Such securing and locating features are described hereafter with reference to <FIG>. Supplementary device <NUM> comprises a housing <NUM> configured to embrace the housing <NUM> of injection device <NUM> of.

<FIG>, so that the injection device <NUM> is at least partially retained within the supplementary device <NUM>, but is nevertheless removable from the supplementary device <NUM>, for instance when injection device <NUM> is empty and has to be replaced. The injection device <NUM> and supplementary device <NUM> may comprise co-operating alignment features (described in more detail hereafter) to ensure that the supplementary device <NUM> is correctly orientated and positioned with respect to the injection device <NUM>.

Information is displayed via display unit <NUM> (shown in <FIG>) of supplementary device <NUM>. The display unit may be a touch sensitive screen. The supplementary device <NUM> may also comprise at least one hardware input (not shown) such as a push button. The supplementary device <NUM> has an outer needle cap (ONC) sensor <NUM>. The ONC sensor may be any suitable form of proximity sensor which allows the supplementary device <NUM> to determine whether the ONC <NUM> is attached to the injection device <NUM> or not. The supplementary device <NUM> also comprises an optical sensor <NUM> for reading the information <NUM> identifying the medicament. The information <NUM> identifying the medicament may be the colour of the housing <NUM> of the injection device, or the colour of an area of the housing or a label affixed to the housing. In these embodiments, the optical sensor <NUM> may be a simple photometer configured to detect the colour. In some other embodiments, the information <NUM> identifying the medicament may be a QR code, or other similar encoded information and the optical sensor <NUM> may be a camera or QR reader.

The processor <NUM> may be configured to check the information <NUM> read by the optical sensor <NUM> against pre-stored information in order to verify that the user is injecting the correct medicament. If the processor <NUM> does not recognise the information <NUM> or recognises the information <NUM> as indicating a different medicament to that which the user should be receiving at that time, then the supplementary device <NUM> may produce an alarm signal. The alarm signal may comprise words or graphics displayed on the display unit <NUM>. Alternatively, or in addition, the supplementary device <NUM> may send an alarm signal to the external device.

The supplementary device <NUM> comprises a battery <NUM> to power the other components. The supplementary device <NUM> comprises a wireless communication module <NUM> for communicating information with an external device. In some embodiments, the wireless communication module <NUM> is a Bluetooth ® communication module <NUM>.

<FIG> shows a schematic view of the supplementary device <NUM> of <FIG> in a state where it is attached to injection device <NUM> of <FIG>.

A plurality of components are contained within the housing <NUM> of supplementary device <NUM>. These are controlled by a processor <NUM>, which may for instance be a microprocessor, a Digital Signal Processor (DSP), Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA) or the like. Processor <NUM> executes program code (e.g. software or firmware) stored in a program memory <NUM>, and uses a main memory <NUM>, for instance to store intermediate results. Main memory <NUM> may also be used to store a logbook on performed ejections/injections. Program memory <NUM> may for instance be a Read-Only Memory (ROM), and main memory may for instance be a Random Access Memory (RAM).

Supplementary device <NUM> may optionally further comprises at least one input transducer, illustrated schematically as a button <NUM>. These input transducer <NUM> allows a user to turn on/off supplementary device <NUM>, to trigger actions (for instance to cause establishment of a connection to or a pairing with another device, and/or to trigger transmission of information from supplementary device <NUM> to another device), or to confirm something. In some other embodiments, the supplementary device <NUM> is automatically turned on/off via the ONC sensor <NUM>.

Processor <NUM> controls a display unit <NUM>, which is presently embodied as a Liquid Crystal Display (LCD). Display unit <NUM> is used to display information to a user of supplementary device <NUM>, for instance on present settings of injection device <NUM>, or on a next injection to be given. Display unit <NUM> may also be embodied as a touch-screen display, for instance to receive user input.

Processor <NUM> also controls a Capacitive Sensor <NUM> and/or a Hall Sensor <NUM>. In some embodiments, the supplementary device <NUM> comprises only the capacitive sensor <NUM> while in some other embodiments the supplementary device <NUM> comprises only the Hall sensor <NUM>. In some further embodiments, the supplementary device <NUM> comprises both the capacitive sensor <NUM> and the hall sensor <NUM> where one may act as a redundant/back-up system for the other. These sensors <NUM>, <NUM> are configured to output signals indicative of the positions of one or more components within the injection device <NUM>. These sensors <NUM>, <NUM> may collectively be referred to as non-contact sensors, since they are able to sense the absolute position and movement of components within the attached injection device <NUM> without contact between the sensors <NUM>, <NUM> and any of the components sensed. It will therefore be appreciated that the position of these sensors <NUM>, <NUM> relative to the injection device <NUM> is important for correct and accurate operation of the supplementary device <NUM>. The processor <NUM> receives these signals and infers an operational state of the injection device <NUM> and causes information regarding the timing of the operation of the injection device <NUM> to be recorded in the main memory <NUM> and/or transmitted to an external device via the wireless unit <NUM>. The operation of these sensors is described in greater detail with respect to <FIG> and <FIG>.

Processor <NUM> further controls an optical sensor <NUM> that is configured to determine an optical property of the housing <NUM> of injection device <NUM>, for example a colour or a shading or a more complex pattern, such as a QR code. The optical property may only be present in a specific portion of housing <NUM>, for example on a label affixed to the housing <NUM>. Information on the colour/pattern is then provided to processor <NUM>, which may then determine the type of injection device <NUM> and/or the type of medicament contained in injection device <NUM>. The optical sensor <NUM> may be a camera unit, and an image of the housing <NUM> may then be provided to processor <NUM> to determine the colour of the housing, sleeve or medicament container by way of image processing. Further, one or more light sources may be provided to improve reading of optical sensor <NUM>. The light source may provide light of a certain wavelength or spectrum to improve colour detection by optical sensor <NUM>. The light source may be arranged in such a way that unwanted reflections, for example due to the curvature of the housing <NUM>, are avoided or reduced. In an example embodiment, the optical sensor <NUM> may be a camera unit configured to detect a code <NUM> (for instance a bar code, which may for instance be a one- or two-dimensional bar code) related to the injection device and/or the medicament contained therein. This code <NUM> may for instance be located on the housing <NUM> or on a medicament container contained in injection device <NUM>, to name but a few examples. This code <NUM> may for instance indicate a type of the injection device and/or the medicament, and/or further properties (for instance an expiration date). This code <NUM> may be a QR code <NUM>. The QR code is in general black and white and thus no colour detection is required on the part of the optical sensor <NUM>. This allows the optical sensor <NUM> to be simple and cheap to manufacture.

Processor <NUM> controls a wireless unit <NUM>, which is configured to transmit and/or receive information to/from another device in a wireless fashion. Such transmission may for instance be based on radio transmission or optical transmission. In some embodiments, the wireless unit <NUM> is a Bluetooth ® transceiver. Alternatively, wireless unit <NUM> may be substituted or complemented by a wired unit configured to transmit and/or receive information to/from another device in a wire-bound fashion, for instance via a cable or fibre connection. When data is transmitted, the units of the data (values) transferred may be explicitly or implicitly defined. For instance, in case of an insulin dose, always International Units (IU) may be used, or otherwise, the used unit may be transferred explicitly, for instance in coded form. The transmitted data may also include a time stamp associated with an injection.

Processor <NUM> receives an input from an ONC sensor <NUM>, which is operable to detect whether the outer needle cap <NUM> is present, i.e. to detect whether the outer needle cap <NUM> is coupled to the injection device <NUM>. A battery <NUM> powers the processor <NUM> and other components by way of a power supply <NUM>. The removal of the ONC <NUM> is detected by the ONC sensor <NUM> and can be used as a wake-up or switch on trigger. Thus the supplementary device may automatically turn on and begin its monitoring processes when the ONC <NUM> is removed. Similarly, when the ONC <NUM> is replaced the supplementary device may automatically power off, thus saving battery power.

The supplementary device <NUM> of <FIG> is thus capable of determining information related to a condition and/or use of injection device <NUM>. This information is displayed on the display <NUM> for use by the user of the device. The information may be either processed by supplementary device <NUM> itself, or may at least partially be provided to another device (e.g. a blood glucose monitoring system or a computing device).

The processor <NUM> is configured to receive signals form the ONC sensor <NUM> and to detect when the ONC <NUM> is not attached to the injection device <NUM>. If the user stores the injection device <NUM> without the ONC <NUM> attached, then the needle <NUM> can become clogged. Therefore, the supplementary device <NUM> is configured to produce an alarm signal if the processor <NUM> detects that the ONC <NUM> has been un-attached for a predetermined length of time following an injection operation. The alarm signal may be sent via the wireless unit <NUM> to the external user device such that the user can be alerted to the need to replace the ONC <NUM> even if they have moved away from the supplementary device <NUM> and injection device <NUM>. Alternatively, or in addition, the alarm signal may comprise the supplementary device <NUM> displaying words and/or graphics on the display unit <NUM> or producing sound. The alarm signal may be used to provide a defined alert time for a user to cease use of the device and to use a new device.

In some embodiments, the supplementary device <NUM> comprises a capacitive sensor <NUM>. Referring now to <FIG>, the operation of the capacitive sensor <NUM> will be described in greater detail.

<FIG> illustrates shows diagrammatically a cut-away through the injection device <NUM> when the injection device is in a pre-injection configuration and a post injection configuration (also referred to as pre-activation and post-activation). The injection device <NUM> comprises a drive spring <NUM>, which is pre-compressed during assembly of the injection device <NUM>. The drive spring <NUM> is maintained in this pre-compressed state until an injection is performed. When a user triggers an injection operation by pressing dose dispense button <NUM>, the dispense mechanism is released and the drive spring decompresses so as to dispense medicament from the cartridge <NUM>.

Various components of the capacitive sensor <NUM> are shown schematically in the lower image in <FIG>. The capacitive sensor <NUM> comprises opposing sets of at least one electrically conductive plate. The plates are supported in the housing <NUM> of the supplementary device <NUM> so as to be adjacent to the injection device <NUM> when the supplementary device <NUM> is attached. The plates may be curved so as to better fit the contours of the supplementary device housing <NUM>. The plates are connected in a circuit so as to form a capacitor. The injection device <NUM> occupies the space between the plates and functions as the dielectric layer of the capacitor. The capacitive sensor <NUM> sends signals to the processor <NUM> via which the processor <NUM> can determine the effective capacitance.

The upper image in <FIG> shows the approximate position of the drive spring <NUM> before an injection has been performed. The drive spring <NUM> is compressed, with the coils or windings of the spring being closely spaced or touching. The lower image in <FIG> shows the approximate position of the drive spring <NUM> after the energy stored therein has been released during an injection process. The coils of the drive spring are spaced further apart. In some embodiments the drive spring is metallic.

In an exemplary method of use, the sensor <NUM> will be set to the capacity of the drive spring <NUM> prior to injection. The capacity change of the electrically conducting material during injection (the relaxing drive spring <NUM>) can be detected by the sensor <NUM>. The injection will be determined as completed when there is no detected change of the electric field (for example, after a pre-determined lapse time, such as after <NUM> seconds holding time). The sensor <NUM> may advantageously be protected against electromagnetic impulses from environmental influences.

<FIG> is a graph showing an exemplary relationship between capacitance and charge before, during and after an injection process. Before the injection device <NUM> is used, the capacitance measured by the capacitive sensor <NUM> is relatively high, due to the presence of a greater amount of the drive spring <NUM> in the region between the capacitor plates. The start and end points of the medicament ejection process are shown. During the ejection, the drive spring <NUM> uncoils such that progressively less of its material is disposed in the region between the capacitor plates. Therefore, the capacitance measured by the capacitive sensor <NUM> decreases during the injection. After the injection device <NUM> has been used, the capacitance measured by the capacitive sensor <NUM> is relatively low. The sensor <NUM> may detect a change of the measured capacitance, so the electronic controller knows that the injection is in process. A display may inform a user of the injection being in process.

It is intended within the scope of the present disclosure that only hall sensors may be used to determine bung or piston position and so determine when an injection process is at the start and end points. In such an embodiment, two hall sensors may be provided, disposed at the start and end positions of the bung or piston. The bung, or piston may be provided with a magnet for detection by the respective hall sensors at the start and end positions. In alternative embodiments, hall sensors may be used in combination with capacitive sensors, to detect both start and end positions of the injection process, as well as to monitor the progress of the injection process between the start and end positions.

The processor <NUM> may be configured to determine that an injection has been completed if the capacitance drops from the relatively high value to the relatively low value and remains there for a predetermined time. The processor <NUM> may be configured to detect the gradual change in measured capacitance in order that the supplementary device <NUM> can distinguish between an injection process and the supplementary device <NUM> being removed from the injection device without an injection being performed, in which case a more sudden drop in capacitance would be expected. The capacitive sensor <NUM> may be shielded so as to protect it from external electromagnetic impulses.

In some embodiments, the supplementary device <NUM> comprises a Hall sensor <NUM> (also referred to as a Hall effect sensor or magnetic sensor). Referring now to <FIG>, the operation of the Hall sensor <NUM> will be described in greater detail. In these embodiments a magnet <NUM> is mounted within the injection device <NUM> on either the distal or proximal end of the plunger. <FIG> illustrates an embodiment in which the magnet <NUM> is mounted on the distal end of the plunger. The injection device <NUM> of <FIG> is in a pre-activation state. The Hall sensor <NUM> is positioned within the supplementary device <NUM> such that it overlays the approximate midpoint of the injection device <NUM> when the two devices are connected together. This is approximately the longitudinal position that the magnet <NUM> will occupy at the end of the injection process.

In the pre-activation state, the Hall sensor <NUM> will detect a very low or no magnetic field due to the relatively large separation between the magnet <NUM> and Hall sensor <NUM>. During the ejection process, the field detected by the Hall sensor <NUM> increases. When the injection device <NUM> is in a post-ejection state, the magnet is located adjacent the Hall sensor <NUM> and the field detected is relatively high.

<FIG> illustrates an alternative arrangement in which a magnet <NUM> is supported on the proximal end of the plunger. In alternative embodiments, the magnet <NUM> may be supported on the syringe bung or stopper. The injection device <NUM> of <FIG> is in a post-activation state. The Hall sensor <NUM> is positioned further towards the proximal end of the supplementary device <NUM>. The choice of whether to use the design in <FIG>, or that of <FIG> may depend on the size of the supplementary device <NUM> and its position when mounted to the injection device <NUM> or on the construction process of the injection device <NUM>.

As with the embodiment described above with reference to <FIG>, the processor <NUM> receives the signals from the Hall sensor <NUM> and can determine whether the injection device <NUM> is in a pre-injection or post-injection state.

The magnet <NUM>, <NUM> may be a permanent magnet or alternatively a Ferro magnetic plastic. An advantage of using a plastic magnet, is that it can be moulded to the plunger rod during manufacture. The plastic magnet may need to be magnetized shortly before final assembly of the injection device <NUM> using a magnetic pulse field.

The processor <NUM> is configured to receive signals from the capacitive sensor <NUM> and/or Hall sensor <NUM> and to infer whether the injection device <NUM> is in a pre-injection state, a post-injection state or whether an injection process is ongoing. The processor <NUM> may control the display unit <NUM> to display different indications to a user depending on the state of the device. This is advantageous as some users may find it difficult to tell whether an injection device <NUM> has been used or not and also as it aids with the injection operations itself, which some users may find difficult without the presence of the supplementary device <NUM>.

<FIG> show alternative embodiments of the invention in which one or more Hall sensors are used. Both Figures show the injection device <NUM> in a pre-activation state. In <FIG>, the supplementary device <NUM> comprises a first Hall sensor <NUM> and a second Hall sensor <NUM>'. The first and second Hall sensors are arranged in the supplementary device <NUM> so as to be spaced at different longitudinal positions along the injection device <NUM>. For example, the first Hall sensor <NUM> may be positioned in the supplementary device <NUM> so as to be located over the centre region of the injection device <NUM>, while the second Hall sensor <NUM>' may be positioned so as to be located close to the distal end of the injection device <NUM>. The injection device <NUM> comprises a magnet <NUM> mounted to the distal end of the plunger. As the magnet <NUM> moves past the first and second Hall sensors <NUM>, <NUM>', signals are induced in the sensors which can be used to determine the position of the plunger.

When the injection device <NUM> is activated, the magnet <NUM> first moves past the second Hall sensor <NUM>'. Signals induced in the second Hall sensor <NUM>' are received by the processor <NUM> and used to determine that the plunger has begun its movement. Thus the processor <NUM> is able to determine that an ejection process has begun. As the magnet <NUM> moves away from the second Hall sensor <NUM>', the signal produced diminishes. As the magnet <NUM> approaches the first Hall sensor <NUM>, the signal from this sensor increases. As the plunger reaches its final position, the magnet <NUM> passes underneath the first Hall sensor <NUM>. The first Hall sensor <NUM> may be positioned such that the magnet <NUM> stops underneath the sensor <NUM> or moves completely past the sensor. In either case, the processor <NUM> is configured to determine from the received signals that the plunger has successfully reached its final position.

In <FIG>, the supplementary device <NUM> comprises a single Hall sensor <NUM>. The injection device <NUM> comprises a first magnet <NUM> mounted to the proximal end of the plunger and a second magnet <NUM>' mounted to the distal end of the plunger. The Hall sensor <NUM> is positioned so that it is located over the central region of the injection device <NUM> and so that the first magnet <NUM> is located underneath or near the sensor <NUM>. When the injection device <NUM> is activated, the first magnet <NUM> moves underneath and away from the Hall sensor <NUM>. Signals induced in the Hall sensor <NUM> are received by the processor <NUM> and used to determine that the plunger has begun its movement. Thus the processor <NUM> is able to determine that an ejection process has begun. As the plunger reaches its final position, the second magnet <NUM>' passes underneath the Hall sensor <NUM>. The Hall sensor <NUM> may be positioned such that the second magnet <NUM>' stops underneath the sensor <NUM> or moves completely past the sensor. In either case, the processor <NUM> is configured to determine from the received signals that the plunger has successfully reached its final position.

In the arrangements shown in <FIG>, the processor can only determine when the plunger arrives at its final position. In the arrangements of <FIG>, the processor <NUM> can determine both that the ejection process has successfully begun and that it has completely finished. Having both these determinations allows for better malfunction detection and reporting. This is advantageous, as the injection device <NUM> itself has no means for detecting malfunctions. Some injection devices have a mechanically operated inspection window, which turns from red to green during ejection, but the remote sensing and detection abilities of the supplementary device <NUM> provide much more useful information and more accurate and reliable detection of malfunctions.

For example, the processor can determine that the plunger has begun its movement and has continued to move away from its initial position. If, when the injection device <NUM> is activated, this detection is not made, the processor <NUM> can determine that the plunger has not moved and that no (or little) medicament has been ejected. If the processor <NUM> detects that the plunger has begun its movement but does not detect that it has reached its final position, it can be determined that some medicament has been ejected, but not the whole amount. The processor <NUM> is configured to write information regarding operation of the device and also details of any malfunctions into the log of the supplementary device <NUM>. This can then be reviewed and evaluated, either by the user or the user's health care professional. Being able to determine not only that a malfunction has occurred, but whether any medicament has been ejected or not is potentially important information, as it will likely inform how to proceed with the user's therapy. Informing a user that there has been a device malfunction but that some medicament has been injected helps to prevent accidental overdosing. The supplementary device <NUM> can additionally sound an alarm and present information to the user via display unit <NUM>. For example, the user can be instructed to seek the advice of their doctor, due to a malfunction of the injection device <NUM> and also informed as to whether any medicament has been ejected from the device.

In some embodiments the supplementary device <NUM> comprises either the capacitive sensor <NUM> or the Hall sensor <NUM>, however in some other embodiments, both sensors may be provided in different parts of the supplementary device <NUM>.

In embodiments where the supplementary device comprises both the capacitive sensor and the Hall sensor, the signals from both of these may be used to detect any mechanical failure of the drug delivery device. <FIG> shows an embodiment of the supplementary device <NUM> comprising both the capacitive sensor <NUM> and first and second Hall sensors <NUM>, <NUM>'. <FIG> illustrates the injection device <NUM> in a post-activation state. The injection device <NUM> comprises a magnet <NUM> disposed on the proximal end of the plunger. As described above with reference to <FIG>, the magnet <NUM> begins underneath or near the second Hall sensor <NUM>' and after activation of the injection device <NUM> moves away and towards the first Hall sensor <NUM>. When the plunger reaches its final position, the magnet <NUM> is underneath or near the first Hall sensor <NUM>. The capacitive sensor <NUM> may be provided at a different location in the supplementary device <NUM>, as shown in <FIG>. The capacitive sensor <NUM> is configured to operate as described above with reference to <FIG>. In this arrangement, the magnet <NUM> is kept away from the capacitive sensor <NUM> so as not to affect its readings. Alternatively, the capacitive sensor <NUM> may be positioned between the two Hall sensors <NUM>, <NUM>' and software may be used to distinguish the signals due to the un-compressing of the spring <NUM> and the movement of the magnet <NUM>.

Having both the capacitive sensor <NUM> and the Hall sensor <NUM>, <NUM>' allows further details on the type of any malfunction to be determined. For example, if the capacitive sensor <NUM> detects that the drive spring <NUM> has un-compressed, but the Hall sensors <NUM>, <NUM>' detect that the plunger has not moved, it can be inferred that a mechanical failure relating to the connection between the drive spring and plunger has occurred, either during manufacture or during use. If the Hall sensors <NUM>, <NUM>' detect that the plunger has moved or is not in the correct initial position, but the capacitive sensor <NUM> detects that the drive spring <NUM> in still completely compressed, it can be inferred that a mechanical fault has occurred such as that the injection device <NUM> was incorrectly assembled or does not contain the correct amount of medicament. Suitable alarm signals and information may be generated and displayed by the supplementary device <NUM> in response to these determinations. The system of <FIG> is also able to detect whether medicament has been ejected or not and so prevent accidental overdoses and inform on how to proceed with the user's therapy in the event of a malfunction.

The processor <NUM> is configured to record a user's injection history. While the injection device <NUM> may be a single use auto-injector, the supplementary device <NUM> is reusable, and is configured to be removed from a used injector <NUM> and attached to a new injector. The processor <NUM> of the supplementary device <NUM> has an internal clock in order to create time stamps associated with the injection events. The clock may be a relative clock or an absolute clock. The supplementary device <NUM> is configured to communicate with an external device through wireless unit <NUM> and the external device may provide an absolute time.

When the supplementary device <NUM> is first attached to a new injection device <NUM>, the optical sensor <NUM> may be activated and the information <NUM> read. The supplementary device <NUM> may communicate the information to a user using the display screen <NUM>. When a user performs an injection, this is detected by the capacitive sensor <NUM> or Hall sensor <NUM> as described above. A time stamp associated with the injection is then created by the processor <NUM>. The processor <NUM> also records and associates with the time stamp the type of medicament injected, using the previously read information <NUM>. An external device (not shown) in the user's possession may be registered and associated with the supplementary device <NUM>. The external device may be a mobile computer or smart phone via the wireless unit <NUM>. The mobile computer or smart phone may run a computer program for managing the user's medical records and injection history. The supplementary device <NUM> is configured to communicate the recorded injection information to the external device.

The processor <NUM> may be pre-programmed with information relating to the frequency at which the user should perform injections. This programming may take the form of a maximum time between injections or a medical regimen associated with the user of the supplementary device <NUM>. For example, the processor <NUM> may be pre-programmed with information specifying that the maximum time between injections should be <NUM> hours. In some other embodiments, the medical regimen may be more detailed, such as to specify specific times of day at which the user is to perform an injection operation using the injection device <NUM>. Alternatively, the processor <NUM> may be configured to calculate a time at which the user should next perform an injection based on the injection history. For example, the time at which the user should perform the next injection may depend on the amount of medicament previously injected and the frequency of the previous injections. The processor may use the previous injection history to calculate a medical regimen for the user.

When the processor <NUM> determines that it is time for the user to perform a subsequent injection, it causes a reminder signal to be sent via the wireless unit <NUM> to the associated external device. The external device may then notify and remind the user that their next injection is due. This is advantageous as the user may not wish to carry the injection device <NUM> and/or supplementary device <NUM> with them, but may in any case by carrying a smart phone or similar device. Thus the user can be reminded of the need for a subsequent injection via a separate device which they carry with them. Furthermore, the injection device <NUM> may need to be kept under specific conditions, such as in a refrigerator or a freezer, such that it is not possible for a user to carry the injection device with them. It is therefore easy for a user to forget about the times at which an injections needs to be performed.

In addition, the processor <NUM> may be configured to use signals received from the capacitive sensor <NUM> or Hall sensor <NUM> to instruct or inform a user regarding `dwell time'. After a user injects a quantity of medicament into their skin, it is advantageous for the needle to be left in position for a short time (e.g. <NUM>-<NUM> seconds). This may allow the medicament to be diffused away from the injection site. If the needle is removed too soon after an injection, it can result in medicament being expressed from the injection site and the user therefore not receiving a full dose. As previously stated the processor <NUM> can use the change in signals received from the sensors <NUM>, <NUM> to determine that an injection is being performed. The processor <NUM> can infer, when the signals received from the sensors <NUM>, <NUM> stop changing, that the injection has been completed. This detection can therefore be used as a trigger to display an indication to the user on the display unit <NUM> instructing them to leave the needle of the injection device <NUM> in the injection site for a predetermined length of time. The indication may be of any suitable form, for example a timer which counts up or down or a graphic which gets larger/smaller or which fills or un-fills. Other methods of indication may also be used such as sound.

In addition to the components described above, the supplementary device <NUM> may comprise an ambient light sensor <NUM>. Sometimes the injection device <NUM> may need to be stored in a refrigerator or a freezer in order to prevent degradation of the medicament over a period of time. The user may attach the supplementary device <NUM> to an unused injection device <NUM> after a previous injection, and store the resulting combined system in the fridge/freezer. The ambient light sensor <NUM> of the supplementary device <NUM> can be used to detect when the fridge/freezer is opened. This can be used as a trigger for initiating an alarm to remind the user regarding the due time of their next injection. As described above this alarm may take the form of sound emitted by the supplementary device <NUM>, text/graphics displayed on the display unit <NUM> and/or a reminder send via the wireless unit <NUM> to the user's smart phone or other external device.

It will be appreciated from the above description that it is important for the correct and accurate functioning of the supplementary device <NUM> that it is accurately positioned and secured on the injection device <NUM>. For example, it is important that the various sensors such as the ONC sensor, optical sensor <NUM>, hall sensor <NUM> and/or capacitive sensor <NUM> are correctly positioned within respect to the components of the injection device <NUM> they are configured to monitor, detect or otherwise interact with.

In order to enable accurate and secure positioning of the supplementary device <NUM> on the injector device <NUM>, the supplementary device may include one or more particular positioning features. The injector device <NUM> may also comprise complimentary features configured to engage with those positioning features of the supplementary device <NUM>.

<FIG> show the supplementary device <NUM> and illustrate such positioning features. <FIG> shows the supplementary device <NUM> during insertion of the injector device <NUM> but before the injector device <NUM> is fully inserted. <FIG> shows the injector device <NUM> fully inserted and secured within the supplementary device <NUM>. <FIG> shows a cross-sectional view along the line Y-Y in <FIG>, with the injector device <NUM> fully inserted and secured within the supplementary device <NUM>. <FIG> shows a cross-sectional view along the line Z-Z in <FIG>. <FIG> shows a cross-sectional view similar to that of <FIG>, but with the supplementary device <NUM> in a release configuration.

The housing <NUM> of the supplementary device <NUM> defines a channel. Within the scope of the invention, the channel may be open along one side or part thereof, or may have a wall around its entire perimeter or circumference. In the exemplary embodiment, the channel comprises a generally cylindrical aperture <NUM> configured to receive the injector device <NUM>. The injector device <NUM> is a substantially cylindrical elongate body having a longitudinal axis X-X as shown in <FIG>. The injector device <NUM> is inserted into the cylindrical aperture <NUM> of the housing <NUM> by sliding the injector device <NUM> in the axial direction shown by arrow 'A' in <FIG>.

The housing <NUM> includes a first alignment feature comprising an elongate slot <NUM> formed on an inside wall of the cylindrical aperture <NUM> at an upper side of the housing <NUM>. The slot <NUM> is open at a front end of the housing <NUM> which faces the proximal end P of the injector device <NUM>. This can also be seen in the cross-sectional views of <FIG>. The outer housing <NUM> of the injector device <NUM> includes a projection <NUM> at an upper side thereof. When the injector device <NUM> is inserted into the supplementary device <NUM>, the projection <NUM> slides into the slot <NUM>. It will be appreciated that, by means of the first alignment feature, the injector device <NUM> can only be inserted into the supplementary device <NUM> when the slot <NUM> and projection <NUM> are aligned, ensuring correct rotational position of the injector device <NUM> relative to the supplementary device <NUM> about the axis X-X. Also, once the injector device <NUM> is inserted into the supplementary device <NUM>, relative rotational movement of the injector device <NUM> relative to the supplementary device <NUM> is prevented by means of the first alignment feature. The first alignment feature thereby serves as an "anti-roll" feature.

Although the channel in the housing <NUM> is described above as comprising a generally cylindrical aperture <NUM> configured to receive the injector device <NUM>, the invention is not intended to be limited to this configuration of an entirely rounded or cylindrical aperture <NUM>. In an alternative embodiment, the channel or aperture <NUM> defined by the housing may include flat portions to locate against the elongate body of the injection device <NUM>. These features of such an embodiment are shown in <FIG>, as opposing slanted flat surfaces <NUM>. Each surface is advantageously equally spaced from the centre line (shown by line Z-Z of <FIG>) of the supplementary device <NUM>. Each surface is advantageously angled by the same degree away either side of a vertical line through the supplementary device (again, shown by line Z-Z in <FIG>). Such flat surfaces may provide reference surfaces, as a third alignment feature, against which the elongate body of the injection device <NUM> abuts. These may advantageously guide the elongate body of the injection device <NUM> to be centrally aligned within supplementary device <NUM>. This may advantageously prevent axial mis-alignment of the injection device <NUM> and supplementary device <NUM> which may otherwise occur if both the outer housing <NUM> of the injection device <NUM> and the aperture <NUM> of the supplementary device <NUM> were entirely circular, due to manufacturing tolerances.

The housing <NUM> further comprises a second alignment feature. In the embodiment shown, the second alignment feature comprises an axial locating mechanism to secure the injector device <NUM> in place within the housing <NUM> once it has been fully inserted and is at the correct position axially relative to the housing <NUM>. The locating mechanism is disposed at a lower side of the housing, substantially opposite the first alignment feature, and is shown in <FIG>. The locating mechanism comprises a securing member which, in the exemplary embodiment, comprises a sprung plate <NUM>. The sprung plate <NUM> has a boss <NUM> extending upwardly from the plate <NUM>. A spring <NUM> is disposed between the underside of the sprung plate <NUM> and the inside wall of the housing <NUM>. The spring <NUM> biases the sprung plate <NUM> in a direction away from the adjacent wall of the housing <NUM> and towards the injection device <NUM>. As shown in <FIG>, the sprung plate <NUM> comprise a curved arm which may be formed integrally with the housing, <NUM>, or may be connected to the housing by mechanical fastening or bonding. The curved arm <NUM> may be biased in a direction towards the injector device <NUM> by virtue of the deflection and material resilience of the curved arm. In such an embodiment, the spring <NUM> may be provided to provide additional biasing force to the sprung plate <NUM>. Alternatively the spring <NUM> may be omitted.

The outer housing <NUM> of the injector device <NUM> includes a recess <NUM> in a lower side thereof. The recess <NUM> is disposed facing the boss <NUM> of the sprung plate <NUM> and is configured to receive the boss <NUM>. When the injector device <NUM> has been fully inserted into the housing <NUM> and is at the correct position in an axial direction relative to the housing <NUM>, the boss <NUM> locates in the recess <NUM> and is held in the recess by the force of the spring <NUM> and/or the resilience of the arm <NUM>. The injector device <NUM> is thereby prevented from movement in the direction of the axis X-X of the injector device by means of the second alignment feature. It will be appreciated that, in the embodiment of the invention shown, the second alignment feature also serves to prevent rotation of the injector device <NUM> relative to the housing <NUM> about the axis X-X, so acts as a secondary anti-rotation feature. It will also be appreciated that, in the embodiment of the invention shown in <FIG>, the force of the spring <NUM> and/or resilience of the arm <NUM> urges the injector device <NUM> upwards against the centrally inwardly angled flat reference surfaces <NUM> and so helps to centrally align the injector device <NUM> within the supplementary device <NUM>.

The axial locating mechanism includes a release member. In the exemplary embodiment, the release member comprises a release lever <NUM>. The release lever <NUM> is configured such that rotation of the release lever <NUM> deflects the sprung plate <NUM> away from the injector device <NUM> to disengage the boss <NUM> from the recess <NUM>. The release lever <NUM> comprises a handle <NUM> on the outside of the housing <NUM>, a shaft <NUM> and a paddle <NUM> projecting radially from the shaft at the opposite end thereof to the handle <NUM>. The release lever <NUM> is rotatable between a rest position, as shown in <FIG>, and a release position, as shown in <FIG>. In the rest position, the paddle <NUM> sits within a cavity <NUM> in the sprung plate <NUM> so that the sprung plate <NUM> is disposed with the boss <NUM> received in the recess <NUM>. When the handle <NUM> is turned through <NUM> degrees into the release position, the paddle <NUM> pushes the sprung plate <NUM> downwards so that the boss <NUM> is disengaged from the recess <NUM>. Although the exemplary configuration of release member <NUM> is shown and described as a release lever <NUM>, the invention is not limited to this particular configuration and other configurations of release member or other release mechanism are intended within the scope of the invention. For example, the release member may comprise a slider with a projection that engages the sprung plate <NUM>.

The housing <NUM> additionally includes a locking mechanism to lock the injector device <NUM> in place once fully received in the housing <NUM>. The locking mechanism comprises a locking lever <NUM> pivotable between an unlocked position shown in <FIG> and a locked position shown in <FIG>. The lever <NUM> includes a pin <NUM> projecting from an inner face of the lever <NUM> which is received in a corresponding hole (not shown) in the outer housing <NUM> of the injector device <NUM> when the lever <NUM> is in the locked position.

In the embodiment shown, the lever <NUM> includes a status indicator <NUM> to indicate to a user whether the lever <NUM> is fully engaged in the locked position. This may help ensure the user only uses the injector device <NUM> when it is correctly assembled and ready for use. Different embodiments of status indicator <NUM> are envisaged within the scope of the invention. The indicator <NUM> may be an LED within the locking lever. For example, the LED may illuminate red when unlocked and green when locked. Alternatively, the LED may be off when unlocked and on when locked, or vice versa. The LED may be activated on or off, or between colours by electrical contact with the housing <NUM> when in the locked position. Such contact may be via the pin <NUM> or by contact with another part of the lever <NUM>. Alternatively, the indicator may be mechanically actuated when the lever <NUM> is moved between the locked and unlocked positions. For example, a coloured plate may be moved into and out of view in a display window of the indicator <NUM>.

The injector device <NUM> and/or the supplementary device <NUM> may be configured to be inoperable until the lever <NUM> is moved into the locked position. For example, the pin <NUM> may provide an electrical contact with a control circuit or switch of the injector device <NUM> and/or the supplementary device <NUM> so that operation is only possible once the lever <NUM> is in the locked position. In addition, the supplementary device <NUM> may be configured such that movement of the lever <NUM> into the locked or unlocked position may trigger one or more of the actions of the supplementary device <NUM> described previously. For example, moving the lever <NUM> into the locked position may turn on the supplementary device <NUM>. Conversely, moving the lever <NUM> into the unlocked position may turn off the supplementary device <NUM>. Also, moving the lever <NUM> into the locked or unlocked position may trigger a pairing or connection function, or initiate transmission of information.

The locking lever <NUM> may be configured to provide an audible feedback when it is securely located in the locked position. For example, the locking lever <NUM> may engage with a click or snap. This may give a user both tactile and audible feedback that the locking mechanism is properly engaged and so an injection process can be started.

It will be appreciated that various configurations of supplementary device <NUM> are envisaged within the scope of the invention which enable user-operation of the injection device <NUM>. For example, in one embodiment, such as that shown schematically in <FIG>, the dose dispense button <NUM> protrudes through an opening in an end of the housing <NUM>. In an alternative embodiment, such as that shown in <FIG>, and particularly <FIG>, an end wall <NUM> of the housing <NUM> may be deflectable so a user can push the end wall to depress the dose dispense button. In a further alternative embodiment (not shown), the end wall <NUM> of the housing <NUM> may include a sliding button which is in abutment with the dose dispense button <NUM>. The sliding button of the housing <NUM> may therefore be depressed to depress the dose dispense button <NUM>.

Engagement and disengagement of the injector device <NUM> and supplementary device <NUM> will now be described. A user inserts the injection device <NUM> into the aperture <NUM> of the housing <NUM> in the direction of arrow A in <FIG>. The user aligns the projection <NUM> with the slot <NUM> and continues to insert the injection device <NUM> into the housing <NUM> such that the projection <NUM> is received in the slot <NUM>.

The user continues to push the injection device <NUM> into the housing <NUM> until fully received therein, as shown in <FIG>. In this position, the boss <NUM> locates in the recess <NUM> to secure the injector device <NUM> in the fully-inserted position. A user then moves the locking lever <NUM> from the unlocked position to the locked position to lock the injection device <NUM> in place in the housing <NUM>. As discussed above, this movement to the locked position may also actuate or prime the injector device, or render the injector device in an operable state. Once the locked position, the status indicator <NUM> indicates to the user that the injector device <NUM> and supplementary device <NUM> are ready for use. The user may then operate the injection device to administer the medicament dose.

Once the medicament delivery process is complete, and the supplementary device <NUM> is to be removed from the injection device <NUM>, a user moves the locking lever <NUM> from the locked position to the unlocked position. The status indicator may indicate to the user that the supplementary device <NUM> is unlocked from the injection device <NUM>. A user then turns the handle <NUM> of the release lever <NUM>, which causes the paddle <NUM> to push the sprung plate <NUM> downwards away from the injection device <NUM>. This causes the boss <NUM> to disengage from the recess <NUM>. The injection device <NUM> is then free to be slid out of the aperture <NUM> in the housing <NUM>. The injection device <NUM> can then be stored for reuse, recycled or disposed of in a suitable manner. The supplementary device <NUM> may then be stored for re-use with another injection device <NUM> at a later time.

It will be appreciated that various alternatives to the exemplary embodiments shown and described above are intended to fall within the scope of the invention, defined by the claims hereafter. In one such embodiment, the first alignment feature may be of an alternative configuration to the elongate slot <NUM> and projection <NUM> shown above. For example, the aperture <NUM> in the housing may be of a non-round shape, and the outer housing <NUM> of the injection device <NUM> may be of a corresponding shape. Therefore, the injection device <NUM> may only be receivable in the housing <NUM> in a particular rotational position relative to the axis X-X. Alternatively, the housing may have one or more flat or shaped alignment surfaces and the outer housing <NUM> may have correspondingly shaped alignment surfaces for abutment with the alignment surfaces of the housing <NUM>. Again, such a configuration of housing <NUM> would ensure that the injection device <NUM> may only be receivable in the housing <NUM> in a particular rotational position relative to the axis X-X. Also, all such alternative embodiments of first alignment feature would prevent rotational movement of the injector device <NUM> relative to the supplementary device <NUM> about the axis X-X and thereby serve as an "anti-roll" feature.

Although the first alignment feature is shown as a slot <NUM> in the housing <NUM>, which is configured to receive a projection <NUM> on the injection device <NUM>, the invention is not limited to this configuration and these features may be reversed. For example, the first alignment feature may comprise a projection formed on the inner face of the aperture <NUM> of the housing <NUM>. Such projection may be configured to engage with a slot formed in the outer housing <NUM> of the injection device <NUM>.

Although the second alignment feature is shown as a slot boss <NUM> on the sprung plate <NUM>, which is received in a recess <NUM> in the outer housing <NUM> of the injection device, the invention is not limited to this configuration and these features may be reversed. For example, the second a projection may comprise a recess formed in the sprung plate. Such a recess may be configured to receive a boss formed on the outer housing <NUM> of the injection device <NUM>.

Furthermore, although the embodiment shown comprises both first and second alignment features, the invention is not limited to this configuration and the supplementary device may alternatively comprise only one alignment feature. Such single alignment feature may preferably be configured to prevent rotational and axial movement of the supplementary device relative to the injection device.

Without limitation, a drug 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 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.

Claim 1:
A supplementary device (<NUM>) configured to be releasably attached to a drug delivery device (<NUM>), the supplementary device comprising:
a housing (<NUM>) having a channel (<NUM>) configured to slidably receive the drug delivery device;
a first alignment feature (<NUM>) to ensure a specific alignment of the supplementary device relative to the drug delivery device and restrict rotational movement of the supplementary device around a drug delivery device;
a second alignment feature to prevent sliding movement of the supplementary device relative to the delivery device once attached thereto;
wherein the second alignment feature comprises a moveable securing member (<NUM>) biased towards the drug delivery device, and a release member (<NUM>) operable to be urged against the securing member to move between a rest position in which the securing member is permitted to engage the drug delivery device (<NUM>), and a release position in which the securing member is moved out of engagement with the drug delivery device.