Patent Description:
Pen type drug delivery devices have application where regular injection by persons without formal medical training occurs. This is increasingly common among patients having diabetes where self-treatment enables such patients to conduct effective management of their diabetes.

For good or perfect glycemic control, the dose of insulin or insulin glargine has to be adjusted for each individual in accordance with a blood glucose level to be achieved. The present invention relates to injectors, for example hand-held injectors, especially pen-type injectors; that is, the present invention relates to injectors of the kind that provide for administration by injection of medicinal products from a multidose cartridge. In particular, the present invention relates to such injectors where a user may set the dose. The dose to be injected can for instance be manually selected at the injector by turning a dosage knob and observing the actual dose from a dose window or display of the injector device.

A user undertaking self-administration of insulin will commonly need to administer between <NUM> and <NUM> International Units. To be able to monitor dosages, for instance to prevent false handling of the device or to keep track of the doses already applied, it is desirable to measure information related to a condition and/or use of the drug delivery device e.g. the injection device, such as for instance information on the injected dose.

<CIT> discloses an injection device incorporating a dose sensing device, the dose sensing device comprising a first component having electrically conductive and non-conductive areas and a second component having one or more contact elements to selectively engage the electrically conductive and non-conductive areas. <CIT> discloses a drug delivery device comprising an encoder pattern provided on an encoder sleeve, and plural electrical contacts. <CIT> discloses a drug delivery device comprising a cylindrical member, wherein the outer surface of the cylindrical member is provided with a single track, the track forming an encoder. <CIT> discloses a drug delivery device comprising a plurality of contacts and a cylindrical member provided with a plurality of tracks together forming an encoder.

According to the present invention, there is provided a drug delivery device according to claim <NUM> and a method of operating a drug delivery device according to claim <NUM>. A drug delivery device is provided, comprising: a housing comprising one or more bridging contacts; a movable dial located at least partially within the housing and arranged to move relative to the one or more bridging contacts, the dial comprising a series of conductive strips on an exterior surface of the dial, wherein the one or more bridging contacts selectively connect
and disconnect conductive strips of the series of conductive strips as the movable dial moves to provide alternating electrical signals; at least one electronic component configured to: detect the alternating electrical signals; determine whether the electrical signals are indicative of contact between conductive strips and bridging contact; and based on said electrical signals, determine a medicament dosage programmed into the drug delivery device, especially an injection device.

In one or more embodiments of the drug delivery device, one may utilize one or more of the following features:.

In another aspect a method of operating a drug delivery device is provided, the method comprising: detecting the alternating electrical signals; determining whether the electrical signals are indicative of contact between conductive strips and bridging contact; and based on said electrical signals, determining a medicament dosage programmed into the drug delivery device, especially an injection device.

The method may further comprise: detecting a voltage at at least one of the series of conductive strips, and comparing the voltage detected at the at least one conductive strip to a threshold voltage.

The method may further comprise: in response to determining that the detected voltage is above the threshold voltage, increasing a dosage count in case.

The method may further comprise: in response to determining that the detected voltage is below the threshold voltage, not increasing a dosage count in case the detected voltage is below the threshold voltage.

The method may further comprise: entering, with a microcontroller, a low-power mode; and waking the microcontroller from the low-power mode upon receiving an electrical signal.

The method may further comprise: connecting a resistance to at least one of the series of conductive strips based in response to determining that the microcontroller is in the low-power mode; and disconnecting a resistance element from at least one of the series of conductive strips in response to determining that the microcontroller woke from the low-power mode.

In some embodiments of the invention, one or more of the following features could be implemented:.

In one embodiment, the drug delivery device comprises an electronic component adapted to detect a voltage detected at at least one of the series of conductive strips, compare the voltage detected at the at least one conductive strip to a threshold voltage, and in case the detected voltage is above the threshold, increase a dosage count; or in case the detected voltage is below the threshold, do not increase a dosage count.

The following description is with reference to the following Figures:.

Referring firstly to <FIG>, an external view of a drug delivery device <NUM> according to embodiments of the invention is shown. The device <NUM> shown in <FIG> is a pen type injection device, having an elongate cylindrical shape, for setting and delivering a medicament, such as insulin. The device <NUM> comprises a housing <NUM> having a first housing part <NUM> and a second housing part <NUM>. A rotatable dial <NUM> is located at a first (or proximal) end of the first housing part <NUM>. The rotatable dial <NUM> has substantially the same outer diameter as the first housing part <NUM>. The second housing part <NUM> may be detachably connected to the second end of the first housing part <NUM>. The second housing part <NUM> is configured to have a needle (not shown) or similar drug delivery apparatus attached to it. To achieve this, the second (or distal) end of the second housing part <NUM> may have a threaded portion <NUM>. The threaded portion <NUM> may have a smaller diameter than the remainder of the second housing part <NUM>.

A display mount <NUM> is located on the first housing part <NUM>. A display may be supported on the display mount <NUM>. The display may be an LCD display, a segmented display or any other suitable type of display. The display mount <NUM> may cover a recess (not shown) in the first housing portion <NUM>. A number of electronic components, described in greater detail with reference to <FIG>, may be disposed underneath the display mount <NUM>.

The first housing part <NUM> contains a drug dose setting and delivery mechanism. The second housing part <NUM> contains a drug cartridge (not shown). The drug contained in the drug cartridge may be a medicament of any kind and may preferably be in a liquid form. The drug delivery mechanism of the first housing part <NUM> may be configured to engage with the drug cartridge of the second housing part <NUM> to facilitate expulsion of the drug. The second housing part <NUM> may be detached from the first housing part <NUM> in order to insert a drug cartridge or to remove a used cartridge. The first and second housing parts <NUM>, <NUM> may be connected together in any suitable way, for example with a screw or bayonet type connection. The first and second housing parts <NUM>, <NUM> may be non-reversibly connected together in such a way that the drug cartridge is permanently contained within the drug delivery device <NUM>. Further the first and second housing parts <NUM>, <NUM> may form part of a single housing part.

The rotatable dial <NUM> is configured to be rotated by hand by a user of the drug delivery device <NUM> in order to set a drug dose to be delivered. The dial <NUM> (shown in detail in <FIG>, <FIG>) comprises an internal threading system (not shown) which causes the dial <NUM> to be displaced axially from the housing <NUM> as it is rotated in a first direction. The dial <NUM> may be rotatable in both directions or only in a first direction. Preferably, the dial <NUM> is rotatable in both directions to allow both increasing (by rotating in the first direction) and decreasing (by rotating in the second direction) the required dose.

The device <NUM> is configured, once a drug dose has been set by rotation of the rotatable dial <NUM>, to deliver the set drug dose. The set drug dose is delivered for example when a user exerts an axial force at the proximal end of the device. The rotatable dial <NUM> may support a dose delivery button <NUM> which is depressed in order to deliver the set drug dose. In an embodiment, the dial <NUM> does not rotate when the dose delivery button <NUM> is depressed. When the dose delivery button <NUM> is depressed, the dial <NUM> moves towards the body <NUM> of the device <NUM> and thus dispenses the drug.

The display <NUM> may be configured to display information concerning the drug dose which has been set and/or delivered. The display <NUM> may further show additional information, such as the actual time, the time of the last usage/injection, a remaining battery capacity, one or more warning signs indicating that a dialled dose has not been fully dispensed, and/or the like.

Referring now to <FIG>, a schematic diagram of an example electrical circuitry <NUM> forming part of the drug delivery device <NUM> is shown. The circuitry <NUM> comprises a microcontroller <NUM>, a non-volatile memory such as a ROM <NUM>, a writable non-volatile memory such as flash memory <NUM>, a volatile memory such as a RAM <NUM>, a display <NUM>, contacts <NUM> (for example conductive strips <NUM>, <NUM>, described below) and a bus <NUM> connecting each of these components. The circuitry <NUM> also comprises batteries <NUM> or some other suitable source of power for providing power to each of the components and a switch <NUM>, described in greater detail below. The circuitry <NUM> also comprises a further component <NUM>. In one embodiment, the further component <NUM> is a comparator. In an embodiment, the further component <NUM> is an analogue to digital converter (also called AD converter hereinafter).

The circuitry <NUM> may be integral with the device <NUM>. Alternatively, the circuitry <NUM> may be contained within an electronic module that can be attached to the device <NUM>. In addition, the circuitry <NUM> may comprise additional sensors, such as optical or acoustical sensors. The circuitry <NUM> may comprise an audible alarm (not shown) which the processor <NUM> may control to sound an alarm when a dialled dose has not been fully dispensed.

The ROM <NUM> may be configured to store software and/or firmware. This software/firmware may control operations of the processor <NUM>. The processor <NUM> utilises RAM <NUM> to execute the software/firmware stored in the ROM to control operation of the display <NUM>. As such the processor <NUM> may also comprise a display driver. The processor <NUM> utilises the flash memory <NUM> to store determined amounts of dose dialled and/or determined amounts of dose dispensed, as will be described in more detail below. The processor <NUM> may be a microcontroller or microcontroller unit.

The batteries <NUM> may provide power for each of the components including the contacts <NUM>. The supply of electricity to the contacts <NUM> may be controlled by the processor <NUM>. The processor <NUM> may receive signals from the contacts <NUM>. The processor <NUM> may determine when the contacts <NUM> are energised, and may be configured to interpret these signals. Information may be provided on the display <NUM> at suitable times by operation of the software/firmware and the processor <NUM>. This information may include measurements determined from the signals received by the processor <NUM> from the contacts <NUM>.

The electronic module containing circuitry <NUM> may be embedded within the dial <NUM>. For example, the electronic module may be embedded within the button <NUM>, which can eliminate the requirement to remove and re-use the electronic module when being used in conjunction with a disposable pen injector or other disposable drug delivery device. The embedded electronic module can enable the recording of doses that are dialled and delivered from the pen. This functionality may be of value to a wide variety of device users as a memory aid or to support detailed logging of dose history. It is envisaged that the electronic module could be configured to be connectable to a mobile device, or similar, to enable the dose history to be downloaded from the module on a periodic basis.

An example operation of the dial <NUM> will now be described with reference to <FIG>.

<FIG> show perspective views of part of a dial <NUM> of a drug delivery device <NUM> suitable for use with the invention. <FIG> shows the dial <NUM> with the button <NUM> taken away. <FIG> shows the dial <NUM> with the button <NUM> in place, and with surrounding components of the body <NUM> of the device <NUM>. <FIG> show a plan view of part of a dial <NUM> of a drug delivery device <NUM> suitable for use with the invention.

The dial <NUM> comprises a sleeve <NUM>. In an embodiment, the sleeve <NUM> is cylindrical and is arranged to rotate relative to the first part of the housing <NUM> during programming of a dosage (but does not rotate relative to the housing <NUM> during delivery of said dose).

In an embodiment, the sleeve <NUM> comprises conductive strips <NUM>, <NUM>, <NUM>. The conductive strips may be printed, plated, or etched on an exterior surface of the movable dosage programming component <NUM> (which exterior surface may be contained within the housing <NUM> when no dosage is set, as in the arrangement shown in <FIG>). For example, the conductive strips <NUM>, <NUM>, <NUM> may be formed from conductive ink. For example, the conductive strips <NUM>, <NUM>, <NUM> may be formed by electroplating. The resistance of the conductive strips <NUM>, <NUM>, <NUM>, if printed with conductive ink, may be in the range 100Ω-1kΩ (depending on the ink chosen). In case the conductive strips <NUM>, <NUM>, <NUM> are electroplated, their resistance may be in the range <NUM>-10Ω.

Some of the conductive strips <NUM>, <NUM> are live source strips <NUM>, which are electrically connected to a voltage supply to provide an electrical potential. The live source strips <NUM> may be electrically connected to a voltage supply via a series resistor to limit the current that can flow in this circuit. Other of the conductive strips <NUM>, <NUM> are sensor strips <NUM>, which electrically connected to input terminals of the processor <NUM>.

The sleeve <NUM> may comprise at least one source strip <NUM> and at least one sensor strip <NUM>. In an embodiment, the sleeve <NUM> comprises more than one of each of source strips <NUM> and sensor strips <NUM>. For example, the sleeve <NUM> may comprise two source strips <NUM> and two sensor strips <NUM>. In principle, the sleeve <NUM> may comprise any suitable number of conductive strips <NUM>, <NUM>, for example three of each, four of each, five of each, six of each, etc. The sleeve <NUM> may comprise the same number of each type of conductive strips <NUM>, <NUM>. The source strips <NUM> may be formed as a continuous strip. The continuous strip may be for example W-shaped (or in a shape of multiple, interconnected U's), with the sensor strips <NUM> positioned in the gaps formed in the W-shape.

The strips <NUM>, <NUM> may be positioned such that there is a sensor strip <NUM> positioned between each two source strips <NUM> and vice versa. Preferably, the conductive strips <NUM>, <NUM> are separated by non-conductive gaps <NUM>. Preferably, there is a non-conductive gap between each pair of sensor strip <NUM> and conductive strip <NUM>. The gaps <NUM> may be made of the same material as the sleeve <NUM>, e.g. non-conductive plastic. Alternatively, the gaps <NUM> may be made of a suitable electrically insulating material.

In an embodiment, the sensor strips are electrically connected to the processor <NUM> embedded in the button <NUM> by conductive contacts <NUM>. The contacts <NUM> are positioned within the sleeve <NUM>. The contacts <NUM> are formed of conductive material, e.g. metal. In an embodiment, one contact <NUM> is provided per source conductive strip <NUM> and one contact <NUM> is provided per sensor conductive strip <NUM>. The number of contacts <NUM> therefore may correspond to a total number of all conductive strips <NUM>, <NUM>. There may be fewer contacts <NUM> than the total number of all conductive strips <NUM>, <NUM> in case the source strips are provided U-shaped, W-shaped or continuously W-shaped, as described above. The contacts <NUM> may be fixed to the sleeve <NUM> in such a way to be in permanent contact with the respective adjacent conductive strip <NUM>, <NUM>.

The body <NUM> of the device <NUM> comprises bridging contacts <NUM>. The bridging contacts <NUM> are formed of conductive material, e.g. metal. The bridging contacts <NUM> are positioned within the body <NUM> adjacent to the first (proximal) end of the housing <NUM>. The bridging contacts <NUM> are fixed within the body <NUM> and are configured to allow a contact between a sensor strip <NUM> and a source strip <NUM>, between a sensor strip <NUM> and a gap <NUM>, or between a source strip <NUM> and a gap <NUM>, depending on turning of the dial <NUM> and therefore also the sleeve <NUM>. The bridging contacts <NUM> are not electrically connected to processor <NUM>.

Preferably, each bridging contact <NUM> has a contact point 304a which is narrower than the gaps <NUM>, to ensure that when the contact point 304a is in contact with any non-conductive gap <NUM>, there is no signal transmitted from the surrounding conductive strips <NUM>, <NUM>.

In one embodiment the bridging contacts <NUM> are formed using a metal pressing (using stainless steel, for example), with three contact points 304a formed as bumps. This manufacturing approach may facilitate the provision of low cost bridging contacts. The bump contacts 304a are formed at the end of cantilevered members to allow a pre-load to be achieved, ensuring good radial contact pressure with the conductive strips <NUM>, <NUM> even in worst case tolerance conditions. The bridging contacts <NUM> may be rotationally and axially aligned within the cylindrical housing <NUM>.

The rotation of the dial <NUM> is encoded by selectively connecting and disconnecting contacts <NUM> (the conductive strips <NUM>, <NUM>) on the dosage programming component, thereby alternating electrical signals received by processor <NUM>. Processor <NUM> may be implemented within any suitable electronic module containing electrical circuitry <NUM>. Turning the dial <NUM> and thus the sleeve <NUM> brings the bridging contact into contact with the conductive strips <NUM>, <NUM>. Contact between a sensor strip <NUM> and a source strip <NUM> via a bridging contact <NUM> closes a circuit between the a sensor strip <NUM> and a source strip <NUM>, the bridging contact <NUM> and the contacts <NUM> associated with the respective conductive strips <NUM>, <NUM>. A voltage is thus detected. This may be registered as "<NUM>" (logic high). Contact between a source strip <NUM> or a sensor strip 306and a gap <NUM> via a bridging contact <NUM> breaks the circuit. This may be detected as "<NUM>" (logic low).

In this way, using the known positioning of the conductive strips <NUM>, <NUM> and the gaps <NUM> turning of the dial <NUM> and the sleeve <NUM> relative to the body <NUM> and the bridging contacts <NUM> may be detected. The known movement of dial <NUM> and the sleeve <NUM> may then be translated into a dialled dose, which may then be stored in a memory and/or displayed and/or transmitted to an external device, as appropriate. Various ways of encoding information may be used; for example, Gray code may be used. For example, the number of conductive strips <NUM>, <NUM>, the width of each conductive strip <NUM>, <NUM> and the gaps <NUM> the configuration of the bridging contact etc. may be taken into account to generate a cyclical Gray code during rotation.

<FIG>, B and 4A, B and 5A illustrate an embodiment comprising four vertical conductive strips <NUM>, <NUM> (two live source strips <NUM> and two sensor strips <NUM>, alternately arranged), which is suitable for encoding <NUM> units of dosage. Alternatively or in addition to a code (e.g. numbers) printed on the sleeve <NUM>, embodiments of the invention use the electrical state of the conductive strips <NUM>, <NUM> themselves to form an input to a microcontroller <NUM>. The rotation of the dial <NUM> can be encoded electronically to identify the selected dose value before the dose is delivered. The simplest Gray code that can be used to count doses and detect direction of rotation is a <NUM>-bit Gray code. The embodiment shown above uses three bridging contacts <NUM>, spaced equidistant around a circumference of the sleeve <NUM>. In this embodiment, the contact points 304a of the bridging contacts <NUM> and each extending between two points on the cylinder that are <NUM>° apart.

Other arrangements are possible, as shown in 2D in <FIG>. For example, the conductive pattern may have a variable strip width and gap ratio, and in conjunction with the three equispaced bridging contacts <NUM> as described above forms a <NUM>-bit quadrature signal during rotation. The black areas represent regions of conductive material (conductive strips <NUM>, <NUM>), and the white areas represent regions where no conductive material has been deposited (gaps <NUM>. However, there are a number of configurations of conductive strips <NUM>, <NUM> and bridging contacts <NUM> that will generate a cyclical Gray code during rotation and so could be used to encode the desired dosage setting.

In general, all the sensor strips <NUM> may be of the same width, or they may vary in width. Alternatively or in addition, the source strips <NUM> can be of the same width, or they can vary in width. As apparent from <FIG>, one of the gaps <NUM> may be wider than the remaining gaps. <FIG> shows a pattern which can be used to generate a <NUM>-bit Gray code.

The sleeve <NUM> may further comprise a 0U detection strip <NUM>. The 0U detection strip <NUM> may be positioned on the sleeve <NUM> adjacent the dose delivery button <NUM>. During dispensing the dialled dose, the 0U detection strip is normally the last part of the contacts <NUM> to be brought in contact with the bridging contacts <NUM>. The 0U detection strip <NUM> may thus be provided to ensure that once the button <NUM> is pushed all the way down towards the body <NUM> and the dialled dose is dispensed, this fact is registered as a separate signal. In other words, the 0U detection strip <NUM> is configured not to be engaged by the bridging contact <NUM> if the dose is not dispensed or not fully dispensed.

Two embodiments of electronic circuit to be used are shown in <FIG>. In both embodiments, the source strips <NUM> are connected to a given electrical potential, as described above. In both embodiments, the electrical potential of the sensor strips <NUM> is measured and used as an input for the microcontroller <NUM>.

In the embodiment of <FIG>, the sensor strips <NUM> are at low voltage (relative to the battery <NUM>) when not connected by the bridging contacts <NUM> to the source strips <NUM>. Once a sensor strip <NUM> is connected by a bridging contact <NUM> to a source strip <NUM>, the sensor strip <NUM> is at a potential close to the battery <NUM>. This higher potential is used as an input for the microcontroller <NUM>. In the embodiment of <FIG>, a sensor strip is at high voltage (i.e. potential close to the battery potential) when not connected to a source strip <NUM>. Once the sensor strip <NUM> is connected to the source strip <NUM> by a bridging contact <NUM>, the potential on the sensor strip <NUM> is lowered. This lower potential is then used as an input for the microcontroller <NUM>.

In the following, the invention is described with regard to the embodiment of <FIG>. It will be apparent to one skilled in the art that the invention is applicable to the embodiment of <FIG>.

The resistance R1 (see <FIG>) ensures that the sensor strip <NUM> is at a stable potential until connected by the bridging contact <NUM> to the source strip <NUM>. Preferably, in order to limit the current drawn from the battery, the resistance R1 is as high as possible. For example, the resistance R1 may be in the order of <NUM> MΩ. The resistance R1 may be e.g. <NUM>. 5MΩ, <NUM>. 2MΩ, <NUM>. 9MΩ -<NUM>. 1MΩ, or 1MΩ. A relatively high value of R1, e.g. in the order of 1MΩ, may help in limiting the current flowing into a user who accidentally touches the strips <NUM>, <NUM>, <NUM>.

The resistance of the bridging contact <NUM> is preferably low, e.g. in the order of <NUM>Ω. The resistance of the bridging contact <NUM> may be for example <NUM>. The resistance R1 is thus high compared to the resistance of the bridging contact <NUM>. The voltage on the sensor strip can be therefore read by the microcontroller <NUM>. Such configuration is advantageous because it reduces power consumption and therefore limits the necessary battery size. Preferably, the microcontroller <NUM> is in a low-power mode whenever the device <NUM> is not used (i.e. ideally for most of the time) in order to further save the battery. The microcontroller <NUM> preferably uses the digital signal generated by the change in potential on the sensor strip <NUM> to wake the microcontroller <NUM> from the low-power mode without consuming additional power.

Upon rotation of the dial <NUM>, the sleeve <NUM> extends axially (helically) outwards from the body <NUM> of the device <NUM>, as described above. This exposes the conductive strips <NUM>, <NUM>. The conductive strips <NUM>, <NUM> can thus be accidentally connected together by other means than the bridging contacts <NUM>. For example, upon accidentally touching the sleeve <NUM> and the conductive strips <NUM>, <NUM>, the user may connect the conductive strips <NUM>, <NUM> by their fingers. If such accidental connection happens in a valid sequence of contacts (i.e. a sequence which could be made by the bridging contacts <NUM> upon turning the dial <NUM> and thus setting the dose), such contact may lead to error in recoding of the dialled and/or dispensed dose.

The situation is illustrated in <FIG>. Preferably, the microcontroller <NUM> is configured to detect a range of values as "<NUM>" (i.e. high potential), and a range of values as "<NUM>" (i.e. low potential). This is shown schematically by lines <NUM> and <NUM>. Any signal that is above the high potential value <NUM> is detected as high potential, i.e. "<NUM>". Any signal that is below the low potential value <NUM> is detected as low potential, i.e. "<NUM>". The area between the lines <NUM> and <NUM> is undefined.

<FIG> shows a reading in a situation where the dial <NUM> is turned and no contacts of the conductive strips <NUM>, <NUM> with user's fingers occurs. As discussed above, the resistance of the bridging contact <NUM> is low. The potential on the sensor strip <NUM> where there is no contact between the sensor strip <NUM> and the source strip <NUM> via the bridging contact <NUM> is therefore close to 0V (i.e. below the low potential line <NUM>). The potential on the sensor strip <NUM> where there is contact between the sensor strip <NUM> and the source strip <NUM> via the bridging contact <NUM> is therefore close to the battery voltage <NUM> (i.e. above the high potential line <NUM>).

<FIG> shows a reading in a situation where the dial <NUM> is turned and a contact of the conductive strips <NUM>, <NUM> with user's fingers occurs between points <NUM> and <NUM>. The contact of the conductive strips <NUM>, <NUM> with the user's fingers may occur n addition to any circuit formed by the bridging contacts. The resistance of the user's fingers is higher than that of the bridging contacts <NUM>. The influence on the sensor strip <NUM> when the bridging contact <NUM> connects the sensor strip <NUM> and the source strip <NUM> is negligible. However, the influence on the potential of the sensor strip <NUM> when the bridging contact <NUM> does not connect the sensor strip <NUM> and the source strip <NUM> is not negligible, and the potential between the points <NUM> and <NUM> falls within the undefined region between the lines <NUM> and <NUM>. This possibly introduces a measurement error in case the undefined value is interpreted as no longer below the low potential line <NUM> (logic low, "<NUM>") and therefore being a high potential value (logic high, "<NUM>").

To mitigate the above-described issue, the circuitry <NUM> is configured to detect potential changes caused by the conductive strips <NUM>, <NUM> connected by the bridging contacts <NUM>, and reject any potential changes caused by the conductive strips <NUM>, <NUM> connected by the user's fingers.

In an embodiment, shown in <FIG>, a comparator <NUM> is provided. A comparator has two analogue inputs (shown as + and - in <FIG>) and one digital output. A sensor strip <NUM> is connected to a first input of the comparator. A second input of the comparator is connected to a constant reference voltage <NUM>. This reference voltage may be set at a value close to the high potential value <NUM>. The digital output of the comparator is logic high ("<NUM>") only in case the potential on the sensor strip <NUM> is higher than the reference value (e.g. above the reference value set to be close to the high potential value <NUM>). Otherwise, the output of the comparator is logic low ("<NUM>").

This allows distinguishing the situations shown in <FIG>. In the situation of <FIG>, the output of the comparator is "<NUM>" each time. However, in <FIG>, the output of the comparator is only "<NUM>" outside points <NUM> and <NUM>, i.e. only when the signal <NUM> from a sensor strip <NUM> not only rises above the low potential value <NUM>, but also above the high potential value <NUM>. In general, the tolerance of a comparator can be much smaller than the width of the undefined region between the lines <NUM> and <NUM>. In addition, because it is possible to set the reference value, the comparator allows higher flexibility (compared e.g. to embodiments in which the low/high potential values <NUM>, <NUM> are properties of a particular microcontroller used).

In case of a <NUM>-bit rotational encoder (i.e. a sleeve <NUM> with two sensor strips <NUM>, two source strips <NUM> and a 0U strip <NUM>, as described above), it is preferred to use three comparators, one per each of the inputs to the microcontroller <NUM>. A first and a second comparator are associated with the two encoder lines (sensor strips <NUM> and source strips <NUM>) and a third comparator is associated with the 0U strip <NUM>. This arrangement is beneficial in mitigating the risk of connecting the respective sensor strips <NUM>, source strips <NUM> or 0U strip <NUM> with the user's fingers.

A further advantage of a comparator as described is its digital output, which may be used as a digital input and a wake-up signal for the microcontroller <NUM> in case the microcontroller <NUM> is in a low-power mode.

In an embodiment, an AD converter (not shown) may be used instead of the comparator. The AD converter may be used to convert the sensor strip <NUM> voltage from an analogue signal to a digital signal. The digital signal may be then compared to a software-set threshold. In this way, the AD converter replicates the behaviour of an external electronic comparator in software. Since many microcontrollers contain embedded AD converters, this arrangement eliminates a need for additional components, such as an additional integrated circuit implementing the comparator of the embodiment described above. This solution is therefore especially suitable for devices in which cost is an issue.

To reduce the power consumption of a continuously running (reading) AD converter and therefore the necessary battery size, the following method may be implemented. An example implementation of the method is illustrated in <FIG>.

By reconfiguring the pins of the microcontroller <NUM>, the signal (voltage) from the sensor strip <NUM> the can be configured as a digital input to wake the microcontroller from the low-power mode. A contact between the source strip <NUM>, the sensor strip <NUM> and the user's finger(s) may cause a transition to be detected that causes the microcontroller to leave the low-power mode. Subsequently, the signal may be read by the AD converter to determine whether the voltage is above threshold (e.g. the high potential value <NUM>) and thus whether the signal corresponds to the source strip <NUM> and the sensor strip <NUM> being connected by a bridging contact <NUM> or by the user's finger(s).

In particular, before entering a low-power mode, the microcontroller202 (which preferably comprises an embedded AD converter) may configure the input pin connected to each of the two sensor strips <NUM> and the 0U strip <NUM> (not shown) as a digital input with an interrupt to wake the microcontroller on a logic level transition (step S1). The microcontroller may then enter a low-power mode (step S2). Thus, when the transition is detected on the sensor strip <NUM> and/or 0U strip <NUM> input pin, the microcontroller <NUM> wakes from the low-power mode (step S3). The microcontroller <NUM> may then reconfigure the input pin connected to each of the three sensor strips <NUM> as an analogue input (step S4). The voltage on the input pins corresponding to the sensor strips <NUM> and/or the 0U strip <NUM> may be read using the AD converter (step S5). The obtained voltage may be compared to the software-set threshold (step S6). The microcontroller <NUM> may therefore determine whether the transition was caused by the source strip <NUM> and the sensor strip <NUM> and/or the 0U strip <NUM> being connected by the bridging contact <NUM> (step S8). In case the transition is determined not to have been caused by the source strip <NUM> and the sensor strip <NUM> and/or the 0U strip <NUM> being connected by the bridging contact <NUM>, the microcontroller <NUM> may wait for a suitable delay, return to configuring the input pin connected to each of the two sensor strips <NUM> and the 0U strip <NUM> (not shown) as a digital input with an interrupt to wake the microcontroller on a logic level transition, and continue the above-described sequence of steps (step S9'). In case the transition is determined to have been caused by the source strip <NUM> and the sensor strip <NUM> and/or the 0U strip <NUM> being connected by the bridging contact <NUM>, the microcontroller <NUM> may increment or decrement the current count of dose selected (step S9). It may then then continue to poll the analogue voltage on the input pins corresponding to the sensor strips <NUM> and/or the 0U strip <NUM> and record the dialled dose, until no activity is detected for a suitable delay and the microcontroller returns to the first step in this sequence, i.e. step S1 (step S10).

As discussed above, it is advantageous from the battery life point of view to have the value of resistance R1 as high as possible, and in particular significantly higher compared to the resistance of the bridging contact <NUM>. However, the lower the resistance R1, the lower the value of resistance bridging the source and sensor strips that causes a measurement error.

To address this issue, in an embodiment (which can be combined with any of the embodiments described above), the arrangement of <FIG> may be employed. The circuitry shown in <FIG> includes an additional resistance element R8. The resistance element can be for example a resistor. The value of the resistance of the resistance element R8 is low compared to the resistance R1. For example, the value of resistance R8 may be in the order of 100kΩ. For example, the value of resistance R8 may be less than 200kΩ, less than 180kΩ, or less than 170kΩ. For example, the value of resistance R8 may be 164kΩ. In general, the value of R8 is selected such that it is sufficiently low compared to the resistance R1 (discussed above), but sufficiently high so that it complies with any given safety limits limiting the current possibly flowing through the user's fingers if the user accidentally touches the contacts.

The resistance R8 is provided in parallel with the resistance R1. Q1 is a switch operated by the microcontroller <NUM>. The switch Q1 can be e.g. a transistor. When the microcontroller <NUM> is in a low-power mode, the switch Q1 is open. The resistance connected to the sensor strip <NUM> is thus high (for example in the order of 1MΩ; the possible values of R1 are discussed above). When the microcontroller <NUM> wakes from the low-power mode, the microcontroller <NUM> closes the switch Q1. The effective value of resistance is reduced from R1 to the parallel combination of R1 and R8, thus making the circuit tolerant to less resistive fingers bridging the source and sensor strips.

Providing the arrangement of <FIG> may help saving battery life. Because the microcontroller <NUM> is expected to be in the low-power state for the majority of its life, this switching of resistance between R1 and the parallel combination of R1 and R8 may have only an insignificant impact on battery life.

The drug container may be, e.g., a cartridge, syringe, reservoir, or other solid or flexible vessel configured to provide a suitable chamber for storage (e.g., short- or long-term storage) of one or more drugs. In some instances, the drug container may be or may include a dual-chamber cartridge configured to store two or more components of the pharmaceutical formulation to-be-administered (e.g., an API and a diluent, or two different drugs) separately, one in each chamber. In such instances, the two chambers of the dual-chamber cartridge may be configured to allow mixing between the two or more components prior to and/or during dispensing into the human or animal body.

The drugs or medicaments contained in the drug delivery devices as described herein can be used for the treatment and/or prophylaxis of many different types of medical disorders.

Examples of disorders include, e.g., diabetes mellitus or complications associated with diabetes mellitus such as diabetic retinopathy, thromboembolism disorders such as deep vein or pulmonary thromboembolism. Further examples of disorders are acute coronary syndrome (ACS), angina, myocardial infarction, cancer, macular degeneration, inflammation, hay fever, atherosclerosis and/or rheumatoid arthritis. Examples of APIs and drugs are those as described in handbooks such as <NPL>, for example, without limitation, main groups <NUM> (antidiabetic drugs) or <NUM> (oncology drugs), and <NPL>on.

Examples of APIs for the treatment and/or prophylaxis of type <NUM> or type <NUM> diabetes mellitus or complications associated with type <NUM> or type <NUM> diabetes mellitus include an insulin, e.g., human insulin, or a human insulin analogue or derivative, a glucagon-like peptide (GLP-<NUM>), GLP-<NUM> analogues or GLP-<NUM> receptor agonists, or an analogue or derivative thereof, a dipeptidyl peptidase-<NUM> (DPP4) inhibitor, or a pharmaceutically acceptable salt or solvate thereof, or any mixture thereof. As used herein, the terms "analogue" and "derivative" refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, by deleting and/or exchanging at least one amino acid residue occurring in the naturally occurring peptide and/or by adding at least one amino acid residue. The added and/or exchanged amino acid residue can either be codable amino acid residues or other naturally occurring residues or purely synthetic amino acid residues. Insulin analogues are also referred to as "insulin receptor ligands". In particular, the term "derivative" refers to a polypeptide which has a molecular structure which formally can be derived from the structure of a naturally occurring peptide, for example that of human insulin, in which one or more organic substituent (e.g. a fatty acid) is bound to one or more of the amino acids. Optionally, one or more amino acids occurring in the naturally occurring peptide may have been deleted and/or replaced by other amino acids, including non-codeable amino acids, or amino acids, including non-codeable, have been added to the naturally occurring peptide.

Examples of insulin derivatives are, for example, B29-N-myristoyl-des(B30) human insulin, Lys(B29) (N- tetradecanoyl)-des(B30) human insulin (insulin detemir, Levemir®); 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-omega-carboxypentadecanoyl-gamma-L-glutamyl-des(B30) human insulin (insulin degludec, Tresiba®); B29-N-(N-lithocholyl-gamma-glutamyl)-des(B30) human insulin; B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin and B29-N-(ω-carboxyheptadecanoyl) human insulin.

Examples of GLP-<NUM>, GLP-<NUM> analogues and GLP-<NUM> receptor agonists are, for example, Lixisenatide (Lyxumia®), Exenatide (Exendin-<NUM>, Byetta®, Bydureon®, a <NUM> amino acid peptide which is produced by the salivary glands of the Gila monster), Liraglutide (Victoza®), Semaglutide, Taspoglutide, Albiglutide (Syncria®), Dulaglutide (Trulicity®), 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.

An examples of an oligonucleotide is, for example: mipomersen sodium (Kynamro®), a cholesterol-reducing antisense therapeutic for the treatment of familial hypercholesterolemia.

The term antibody also includes an antigen-binding molecule based on tetravalent bispecific tandem immunoglobulins (TBTI) and/or a dual variable region antibody-like binding protein having cross-over binding region orientation (CODV).

Claim 1:
A drug delivery device (<NUM>), comprising:
a housing (<NUM>,<NUM>) comprising one or more bridging contacts (<NUM>);
a movable dial (<NUM>) located at least partially within the housing and arranged to move relative to the one or more bridging contacts (<NUM>), the dial comprising a series of conductive strips (<NUM>, <NUM>, <NUM>) on an exterior surface of the dial (<NUM>),
wherein the series of conductive strips comprise at least one source strip (<NUM>) connected to a battery and at least one sensor strip (<NUM>) connected to at least one electronic component,
wherein the one or more bridging contacts (<NUM>) selectively connect and disconnect a source strip (<NUM>) to a sensor strip (<NUM>) as the movable dial (<NUM>) moves to provide alternating electrical signals,
wherein the one or more bridging contacts are not connected to the at least one electronic component except when connected via a sensor strip;
wherein the at least one electronic component (<NUM>, <NUM>) is configured to:
detect the alternating electrical signals;
determine whether the electrical signals are indicative of contact between conductive strips and bridging contact; and
based on said electrical signals, determine a medicament dosage dialled into the drug delivery device.