Patent Application
20210283339
The present invention relates to a rotary dosage sensing module for a pen drug delivery device and a method of assembling the same.
Within diabetes performing the necessary insulin injections at the right time and in the right dose size is essential for managing the disease, i.e. compliance with the specified insulin dosage regimen is important to control the blood sugar level and to minimise the risk of hypoglycemia/hyperglycaemia episodes. In order to make it possible for the patient herself/himself or the HCP to see, if the patient follows the recommended insulin dosage regimen, it is desirable that a log of the dose sizes and the time each dose was taken is kept. It's even better if these data can be transferred to an external source, e.g. mobile phone, server or cloud, for further analysis in order to allow for some guidance to recommended doses and/or adjustments to a present dosage regimen, if needed.
Data capturing/monitoring functionality have been proposed for injection devices earlier (see e.g. WO 2010/052275 and U.S. Pat. No. 7,008,399) however most devices are without data capturing. Also durable add-on modules to injection devices have been proposed (see e.g. WO 2010/098927), but as an add-on it requires the users to keep hold of a further device besides their injection pen and blood sugar measurement equipment. It has been also proposed to provide an integrated dose capture unit for a durable pen device (see WO 2014/128155). Further references describe dosage sensing mechanisms, such as US2016/015903 and WO2006/045523.
A significant part of insulin patients today use disposable pen devices with a prefilled drug cartridge to inject their drug, e.g. insulin or GLP-1 or a combination thereof. However, opposite to durable injection pens, disposable pens with prefilled non-interchangeable drug cartridges are normally made of cheaper components, as their FMC (Full Manufacturing Cost) need to be kept low. For that reason none of the disposable pens in the market today are equipped with integrated electronics like a dose data capturing unit, processor(s), power source(s) etc., which is why only add-on devices for disposable pens exist.
Having regard to the above, a cost-effective, compact and reliable rotary sensor module to be integrated into or being integrated in a disposable pen drug delivery device enabling the delivery device to accurately detect dosage data (size and time) without the need for an add-on accessory attached to the pen device has been developed by the applicant of this application and described in detail in WO 2018/141571.
Such a sensor module is powered by a battery that may lose power during the manufacturing process, if the battery is installed too soon during assembling. This lost power will limit the lifetime of the device. This may be a problem for the manufacturing because it requires to have very strict manufacturing policy to limit the amount of power lost during production. If modules spend too much time on the shelf while powered entire lots of modules won't meet expected device lifetime and will have to be reworked or replaced, which affects yields and ultimately cost.
Hence, it is desirable to provide a sensor module that enables an assembly process ensuring a long lifetime of the power source of the sensor module. It is further desirable to provide such a sensor module which allows for a flexible and cost-effective assembly process.
In the disclosure of the present invention, embodiments and aspects will be described which will address one or more of the above desires and/or which will address objects or desires apparent from the following text.
According to a first aspect a method is provided for assembling a prefilled drug delivery device with an electronic rotary dosage sensing module for sensing the amount of drug being expelled from the delivery device, the device comprising a preassembled dosage engine part with a dose setting and expelling mechanism and a preassembled drug holding part with a drug-filled cartridge having a displaceable piston and an outlet, the dose expelling mechanism having a piston rod with a distal tip part to be rotationally and axially advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet, when the delivery device is assembled. The electronic sensing module comprises a first housing part and a second housing part, each housing part having attachment means for attaching them to each other to form a single common sensing module house for at least partly housing; power source unit retaining means for receiving and retaining a power source unit, a power source unit, a processor unit and a sensor unit. The sensor unit comprises a first sensor part comprising a printed circuit board, e.g. a flexible printed circuit board sheet, having a first surface on which is disposed a plurality of individual electrical conductive sensor areas arranged in a pattern, and a second sensor part arranged opposite to the first sensor part and adapted to be directly or indirectly attached to said distal tip part of the piston rod to thereby follow the rotation of the piston rod during dose expelling, the second sensor part comprising a plurality of electrically connected contact structures. The contact structures are adapted to, upon relative rotational movement between the first and second sensor part, electrically connect different individual electrically conductive sensor, each electrical connection generating an electrical signal to the processor unit being indicative of the rotational position between the first and second sensor part, and wherein the processor unit is adapted to process said signals to determine the amount of relative rotations between the first and second sensor part and thereby calculate the expelled dosage size based on the determined amount of relative rotations, and where the second housing part is adapted to engage said drug-filled cartridge and/or displaceable piston, when the delivery device is assembled, such that no rotation between the second housing part and drug-filled cartridge and/or piston is possible, and wherein the method comprises the steps of;
By designing the housing of the module in two separate parts, the installment of the power source unit and a subsequent final attachment of the two housing parts together and final assembling of the delivery device can be done at different locations in the assembly process, i.e. the module doesn't have to be preassembled completely, including the power source, before assembling the delivery device, but can be assembled along the production line as the delivery device is being assembled.
This flexibility allows for optimal design of a production line while minimizing power lost due to the fact that the power source unit can be installed later in the process. Thereby impact of the life of the power source unit is mitigated by the design of the module itself. By allowing for easy installment of the power source unit before delivery to production, the amount of time power is consumed during manufacturing can be controlled.
The engaging between the second housing part and the cartridge and/or piston may be based on any suitable friction- or form-based engagement. In particular, the engagement to the elastomeric piston could be based on gluing or by means of protrusions on the second housing part either penetrating into the piston or providing sufficient friction to prevent relative rotation between the piston and second housing part.
In an embodiment the distal tip part of the piston comprises a central bore and a circumferential portion having one or more deflectable gripping arms, and wherein the second sensor part comprises a cylindrical part extending through an opening in the first housing part and having one or more protrusions located on an outer surface. In this embodiment, the method step a) comprises moving said cylindrical part into said bore, whereby the deflectable gripping arms deflect over said protrusions and subsequently grip around said protrusions and provide a locked interconnection between the second sensor part and piston rod not allowing any relative rotation between the sensor part and the piston rod. The first housing part, power source unit retaining means, the processor unit, and the sensor unit may be preassembled before performing step a) of the assembling method. The first sensor part is preferably attached to the first housing part such that no relative rotation between the sensor part and housing part is possible, whereas the second sensor part is positioned in the first housing part with its cylindrical part extending through said opening and can rotate relative to the first housing part and the first sensor part.
In an embodiment the step of positioning the power source unit comprises moving the power source unit into the retaining means in a direction perpendicular to the axis of rotation of the piston rod.
In another embodiment the step of positioning the power source unit comprises moving the power source unit into the retaining means in a direction parallel to the axis of rotation of the piston rod.
The power source unit is preferably a coin cell battery.
In another aspect, a electronic rotary dosage sensing module assembly is provided for a prefilled drug delivery device comprising a dosage engine part with a dose setting and expelling mechanism and a drug holding part with a drug-filled cartridge having a displaceable piston and an outlet, the dose expelling mechanism having a piston rod with a distal tip part to be rotationally and axially advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet. The electronic module comprises a first housing part, a second housing part, each housing part having attachment means for attaching them to each other to form a single common sensing module house for at least partly housing a power source unit retaining means for receiving and retaining a power source unit, a power source unit, a processor unit and a sensor unit. The sensor unit comprises a first sensor part adapted to be directly or indirectly fixed to a part of the delivery device not rotating during dose expelling and comprising a printed circuit board, e.g. a flexible printed circuit board sheet, having a first surface on which is disposed a plurality of individual electrical conductive sensor areas arranged in a pattern, and a second sensor part arranged opposite to the first sensor part and adapted to be indirectly or directly attached to said piston rod to thereby follow the rotation of the piston rod during dose expelling, the second sensor part comprising a plurality of electrically connected contact structures. The contact structures are adapted to, upon relative rotational movement between the first and second sensor part, electrically connect different individual electrically conductive sensor areas, each electrical connection generating an electrical signal to the processor unit being indicative of the rotational position between the first and second sensor part, and wherein the processor unit is adapted to process said signals to determine the amount of relative rotations between the first and second sensor part and thereby calculate the expelled dosage size based on the determined amount of relative rotations. The second housing part is adapted to engage said drug-filled cartridge and/or displaceable piston, when the sensor module is inserted in drug delivery device, such that no rotation between the second housing part and drug-filled cartridge and/or piston is possible.
In another aspect, an electronic rotary dosage sensing module assembly is provided for a prefilled drug delivery device comprising a dosage engine part with a dose setting and expelling mechanism and a drug holding part with a drug-filled cartridge having a displaceable piston and an outlet, the dose expelling mechanism having a piston rod with a distal tip part to be rotationally and axially advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet. The electronic module comprises a first housing part, a second housing part, each housing part having attachment means for attaching them to each other to form a single common sensing module house for at least partly housing a power source unit retaining means for receiving and retaining a power source unit with a (−) and a (+) terminal for powering the sensing module, a power source unit, a processor unit and a sensor unit. The sensor unit comprises a first sensor part adapted to be directly or indirectly attached to a part of the delivery device not rotating during dose expelling and comprising a printed circuit board, e.g. a flexible printed circuit board sheet, having a first surface on which is disposed a plurality of individual electrical conductive sensor areas arranged in a pattern, some of which being electrically connected to the (−) terminal of the power source unit, when the power source unit is retained in said retaining means and some of which being connected to the processor unit, and a second sensor part arranged opposite to the first sensor part and adapted to be directly or indirectly attached to said piston rod to thereby follow the rotation of the piston rod during dose expelling, the second sensor part comprising a plurality of electrically connected contact structures. The contact structures are adapted to be connected to the (−) terminal of the power source unit via those electrically conductive sensor areas that are connected to (−) terminal of the power source unit, when the power source unit is retained in said retaining means, the contact structures being adapted to, upon relative rotational movement between the first and second sensor part, electrically connect different individual electrically conductive sensor areas to the processor unit to thereby close an electrical circuit between the (−) terminal and the processor unit for the different conductive sensor area, each electrical connection generating an electrical signal to the processor unit being indicative of the rotational position between the first and second sensor part, and wherein the processor unit is adapted to process said signals to determine the amount of relative rotations between the first and second sensor part and thereby calculate the expelled dosage size based on the determined amount of relative rotations. The second housing part is adapted to engage said drug-filled cartridge and/or displaceable piston, when the delivery device is assembled, such that no rotation between the second housing part and drug-filled cartridge and/or piston is possible.
In an embodiment the distal tip part of the piston comprises a central bore and a circumferential portion having one or more deflectable gripping arms, and wherein the second sensor part comprises a cylindrical part extending through an opening in the first housing part and having one or more protrusions located on an outer surface, and where said cylindrical part is adapted to be moved into said bore, so that the deflectable gripping arms deflect over said protrusions and subsequently grip around said protrusions to provide a locked connection between the second sensor part and piston rod not allowing any relative rotation between the sensor part and piston rod.
Embodiments of the sensing module assembly and its parts and construction is further described in the following.
The conductive sensor areas and contact structures could be connected differently to the power source unit and processor unit and still generating the signals to the processor unit. For example the conductive sensor areas could be connected to the (−) terminal, whereas the contact structures could be connected to the (+) terminal via the processor unit.
By using a flexible printed circuit board (PCB) sheet a very compact module can be obtained compared to using a rigid thicker PCB. Further the electrical connection to the power source unit is easier by use of flexible PCB than using a rigid PCB, and the flexible printed circuit board sheet may e.g. be folded around and adhered to the power source unit and where the first surface of the first sensor part then can be supported by a surface of power source unit. Even further, by use of a flexible PCB sheet, one side of the power source unit can be utilised as a conductive surface area for the sensor unit, as further explained below in connection with one of the embodiments. On the other hand, using a rigid PCB will lower manufacturing costs significantly. Furthermore, given its dimensionally stable nature a rigid PCB can be utilised as a structural part of the module, reducing the number of components in the construction and thus making the assembly process both simpler and cheaper.
The sensor unit is based a rotary sensor principle where the conductive sensor areas in turn are switched in and out of conductive contact with the electrical circuit, a principle providing a very reliable dosage sensing. Further, such as system requires a minimum of power to operate meaning that the size of the power source unit can be limited and thus require little space. Further, as the power requirement to the sensor unit is limited, the cost of the power source can be kept low.
The structures of the second sensor part comprise electrical conductive material providing direct electrical contact to the conductive sensor areas, e.g. as shown in the embodiment of
The module may comprise an electrical switch mechanism to open the electrical circuit to a sensor area after the electrical circuit has been closed and an electrical signal has been received by the processor unit for the sensor area, the switch mechanism being controlled by the processor unit.
The electrical switch mechanism may comprise a pull-up resistor to open the electrical circuit to a sensor area a predefined time after the electrical circuit has been closed and an electrical signal has been received by the processor unit for the sensor area, the pull-up resistor being controlled by the processor unit. This will effectively save power as the sensor areas don't need to be powered up all the time to monitor sensor transitions.
However, a detection of the next sensor transition for this specific sensor area will not be detected as the electrical circuit is open by the pull-up resistor. A way of reducing this problem is to implement an intelligent control of the pull-up resistors. Initially, only pull-up resistors for all open electrical circuits are activated. When a sensor transition is detected all pull-up resistors are activated, allowing software in the processor unit to detect all sensor transitions and a timer is started. Every time a sensor transition is detected, the timer is reset to its original value, and when the timer times out, the system reverts to only having the pull-up resistors for open electrical circuits activated. The sensor will consume power during and shortly after a detected transition but will zero-power when static.
The individual electrically conductive sensor areas may be distributed circumferentially around a centre axis (B) of the first sensor part and where the module further comprises a centering element with a bearing cup part having a centre axis (C) and arranged in relation to the first sensor part such that said centre axis (C) coincides with the centre axis (B), the bearing cup part being adapted to maintain a distal tip part of the piston rod in a position, during dose expelling, where the centre axis (A) is coinciding with the centre axis (B).
By providing the centering element with a bearing cup part, there is completely alignment between the first and second sensor part, which is essential for the rotary sensor to detect every transition accurately. If there is only a minor misalignment, then the contact structures of the second sensor part may not engage the sensor areas of the first sensor part properly but jump some connections and not generate a signal. Thereby the readout from the rotary sensor will be inaccurate resulting in a wrong determination by the processor unit of the number of relative rotations and thus wrong dose size calculation. Even very small deviations in centering can result in an incorrect measurement of dose size.
Furthermore, by having the centering element with the bearing cup part located exactly at the center of the axis of rotation, the torque exerted to rotate the second sensor part in relation to the first sensor part is minimised leading to a minimal additional torque required to drive the expelling mechanism in the injection device. Without this centering element a larger torque would be needed, which would lead to a larger spring in the dose expelling mechanism of an automatic pen or a larger injection force to be applied manually by the user for a manual pen.
In an exemplary embodiment the second sensor part is adapted to form part of the distal tip part of the piston rod. In that case the bearing cup part is adapted to receive and maintain the part of the second sensor part forming the distal tip part in a position, during dose expelling, where the centre axis (A) is coinciding with the centre axis (B).
To optimise the centering of the piston rod and thereby second sensor part in relation to the first sensor part and to minimise the torque needed to rotate the two parts in relation to each other, the bearing cup part preferably has a rotationally symmetrical shape around its centre axis (C).
The cross-sectional shape of the bearing cup part, seen parallel to the centre axis (C), may vary in form depending on desired level of play between the distal part of the piston rod and the cup part. The cross-sectional shape may e.g. be substantially V- or U- or trapezoidal- or square-shaped.
The centering element and first sensor part are arranged in a fixed mutual position, such that their respective centre axis' coincide. To provide this mutual fixed position, the centering element may either be soldered or riveted or glued to the first sensor part, or it may be formed integrally with the first sensor part.
In an exemplary embodiment the bearing cup part is made of electrically conductive material and connected to the (−) terminal of the power source unit and wherein the second sensor part, when maintained in the bearing cup part, is electrically connected to the bearing cup part. This would allow for an electrical ground signal to be passed to the second sensor part. For further details on such an embodiment reference is made to
The number of individual electrical conductive sensor areas and contact structures may vary depending on the specific use (drug, pen etc.) and desired code pattern, e.g. a Gray code or quadrature code pattern. The number of sensor areas may e.g. be 3 or 4 or 6 or 8 or even more such as 24 or 48 or 72, and the number of contact structures may be 2 or 3 or 4 or even more.
The conductive sensor areas may be provided either by disposing, e.g. by printing, layer(s) of conductive material on the printed circuit board in specific patterns or by first disposing layer(s) of conductive material on the printed circuit board and afterwards removing material to form the sensor areas. The conductive material may be any suitable conductive material, such as silver, copper, carbon or gold and the thickness of the layer(s) may be e.g. 0.01-0.05 mm, but it can be more or less than that.
The first surface on which the conductive sensor areas are arranged may extend substantially perpendicular to or parallel with said axis of rotation (A).
If a flexible printed circuit board sheet is used this may be a thin foil with a thickness of e.g. 0.05-0.1 mm meaning it easily can be folded as needed, which allows for a very compact construction of the module, as depicted in the examples in the figures. As the flexible printed circuit board sheet can be mass produced, e.g. in processes like a “role-on-role” process allowing thousands of individual sheets to be printed fast, a comparatively low cost per sheet can be achieved.
The power source unit is preferably a standard battery, e.g. a coin cell, however alternatively it may also be a power source disposed on the PCB in the form of a printed battery allowing for an even more compact construction of the module. As the processor unit preferably should be able to keep track of time, e.g. through a real time clock unit, the power source unit may be adapted to supply a low “sleep current” to the processor unit in order to continuously power the clock unit.
The sensor unit may be adapted to be switched from an inactive (off) state into an active (on) state by an initial first relative axial and/or rotational movement between the first and second sensor part. For example the sensor unit may be in “off” mode prior to dose expelling and then be switched “on” just before dose expelling, e.g. during activating the dose expelling mechanism of the pen. By activating the sensor unit just before dose expelling, the module will be able to determine the exact relative position between the first and second sensor part before the two parts start rotating relative to each other.
The processor unit may be in the form of a microprocessor, microcontroller or CPU, which may be of a general purpose design or be specifically designed for the actual device. The processor unit is adapted to, based on the signals received from the dosage sensor unit indicative of the relative rotational position between the first and second sensor part, to calculate a corresponding expelled dose and store this data, including the time for when each dosage of drug was taken. However, instead of the processor unit calculates the actual dose amount, the stored data may be in the form of no. of rotation data only, this allowing a receiving external unit, e.g. a smartphone or PC, to calculate the actual drug dose amounts based on supplied information in respect of the type of drug, type of cartridge, and type of device.
The module preferably comprises a communication unit to wirelessly communicate the stored data to an external device. The communication unit may be disposed on the printed circuit board. The communication unit may be adapted to communicate, via communication technologies like NFC, Bluetooth, BLE (Bluetooth Low Energy), Wi-Fi, ZigBee, ZigFox, LoRa, GSM, Narrow Band or any other wireless communication technology, the dosage data to any unit, such as a smartphone, server or cloud.
Most existing piston rods of the type which rotates during expelling of a dose comprise a distal piston-engaging foot or washer allowing the piston rod to freely rotate during out-dosing while ensuring non-rotational engagement with the elastomeric piston. The sensor module may substitute this piston rod foot, i.e. besides providing dosage sensing it provides the same function as a piston rod foot or washer. As the size of the module can be of the same size as a piston rod foot or washer an integration of the module into a pen will require very limited modifications of the pen. In such embodiment, the module is positioned in between the piston and piston rod with the first sensor part engaging the piston such that no rotation between the piston and the first sensor part is possible and with the second sensor part engaging an end portion of the piston rod such that no rotation between the second sensor part and piston rod is possible, and wherein the module may be adapted to be moved axially into the cartridge corresponding to the axial movement of the piston and piston rod during expelling of a dose. The piston rod will during expelling of a dose exerts a distally directed force on the module, the force being transferred to the piston by the module. The power source unit of the module may constitute the load bearing part transferring the force from the piston rod to the piston.
In another embodiment, the module is adapted to be integrated into the pen in an end opposite to the end containing the cartridge, i.e. in the end of the pen normally containing the dose setting and dose activation mechanism. A detailed description of such integration is provided in connection with
Adapted for the specific purpose of being arranged in either end of the pen as described above, the module may have an effective diameter of less than 20 mm, less than 15 mm, less than 10 mm or less than 8 mm, and a height of less than 10 mm, less than 8 mm, less than 6 mm or less than 4 mm.
According to another aspect, a rotary dosage sensing module is provided for a pen drug delivery device comprising a drug-filled cartridge with a displaceable piston and an outlet and a piston rod to be axially advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet, the piston rod rotating relative to the piston around an axis of rotation (A) during axial movement. The module comprises a power source unit with a (−) and a (+) terminal, a processor unit connected to the (−) and (+) terminals of the power source unit, and a sensor unit comprising; a first sensor part adapted to be directly or indirectly fixed to a part of the delivery device not rotating during dose expelling, the first sensor part comprising a printed circuit board, e.g. a flexible printed circuit board sheet, having a first surface on which is disposed a plurality of individual electrical conductive sensor areas arranged in a pattern, some of which being electrically connected to (−) terminal of the power source unit and some of which being connected to the processor unit, and a second sensor part arranged opposite to the first sensor part and adapted to be directly or indirectly fixed to the piston rod to follow the rotation of the piston rod during dose expelling, the second sensor part comprising a plurality of contact structures, and wherein the contact structures are adapted to, upon relative rotational movement between the first and second sensor part, close an electrical circuit between the (−) terminal and the processor unit for the different conductive sensor area, each electrical connection generating an electrical signal to the processor unit being indicative of the rotational position between the first and second sensor part, and wherein the processor unit is adapted to process said signals to determine the amount of relative rotations between the first and second sensor part and thereby calculate the expelled dosage size based on the determined amount of relative rotations.
In one embodiment, the dosage sensor unit further comprises a second surface area arranged perpendicularly relative to the axis of rotation and axially offset to the first surface of the first sensor part with the individual electrical conductive sensor areas and wherein an electric conductive material connected to the (−) terminal forms the second surface area, and wherein a spacer is arranged to provide axial spacing between the first and second surface areas but to enable individual sub-areas of the first surface area carrying the individual electrical conductive sensor areas to be deflected to bring the different individual electrical conductive sensor areas into electrical contact with the second surface area when the first surface area is acted upon by the individual contact structures of the second sensor part to close the electrical circuit between the (−) terminal and the processor unit for the different sensor areas. A conductive surface area of the power source unit may constitute said second surface area.
The spacer may comprise any kind of material in the state of solid or liquid or gas.
According to another aspect of the invention, a module as described above is provided in combination with a pen drug delivery device comprising a housing, a drug-filled non-interchangeable cartridge with a displaceable piston and an outlet and a piston rod to be advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet, the piston rod rotating relative to the piston and housing during axial movement, and wherein the first sensor part of the module is directly or indirectly engaged with the housing such that no relative rotation between the housing and the first sensor part is possible, and the second sensor part of the module is directly or indirectly engaged with the piston rod such that no relative rotation between the piston rod and the second sensor part is possible.
According to an even further aspect of the invention, a rotary dosage sensing module is provided for sensing dosage sizes in a pen drug delivery device comprising a drug-filled cartridge with a displaceable piston and an outlet, and dose expelling means with a piston rod rotating relative to said piston during dose expelling to drive and displace said piston towards said outlet and thereby expel a dosage of drug through the outlet. The sensor module defines an axis of rotation and comprises a power source unit with a (+) and a (−) terminal, a processor unit connected to the (−) and (+) terminal, and a sensor unit comprising a first cylindrical-formed rotary sensor part having a plurality of individual electrically conductive sensor areas arranged in a pattern around the cylindrical surface extending parallel to the axis of rotation, each sensor area being connected to the (−) terminal of the power source unit. Said first rotary sensor part being adapted to be indirectly or directly fixed to the piston rod to follow the rotation thereof during dose expelling. The sensor module further comprises a second stationary sensor part adapted to be directly or indirectly fixed to a part of the delivery device not rotating during dose expelling, the stationary sensor part comprising a printed circuit board, e.g. a flexible printed circuit board sheet, having a first surface on which is disposed a plurality of contact structures arranged in a pattern, each being electrically connected to said processor unit, and wherein the rotary and stationary sensor part are arranged co-axially and at least partially inside each other such that the contact structures are adapted to, upon relative rotational movement between the first and second sensor part, electrically connect different individual electrically conductive sensor areas to the processor unit to thereby close an electrical circuit between the (−) terminal and the processor unit for the specific conductive sensor area, each electrical connection generating an electrical signal to the processor unit being indicative of the rotational position between the first and second sensor part, and wherein the processor unit is adapted to process said signals to determine the amount of relative rotations between the first and second sensor part and thereby calculate the expelled dosage size based on the determined amount of relative rotations.
According to a further aspect of the invention a dosage sensing module is provided for a pen drug delivery device comprising a drug-filled cartridge with a displaceable piston and an outlet and a piston rod to be advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet, the piston rod rotating relative to the piston during axial movement, said module comprising; a dosage sensor unit comprising a first sensor part adapted to be directly or indirectly fixed to a part of the delivery device not rotating during dose expelling, the first sensor part having a plurality of individual electrical conductive sensor areas, a second sensor part adapted to be directly or indirectly fixed to the piston rod to follow the rotation thereof during dose expelling, the first and second sensor part being rotatable relative to each other and arranged axially offset to each other and perpendicularly relative to the axis of rotation, the module further comprising a processor unit, a power source unit adapted to power at least the dosage sensor unit and processor unit, and a printed circuit board, e.g. a flexible printed circuit board sheet, on which is disposed said plurality of individual electrical conductive sensor areas and electrical conductor(s) for providing electrical connections between the plurality of individual electrical conductive sensor areas, the processor unit and power source unit, and wherein said second sensor part of the sensor unit comprises individual structures that together with said individual electrical conductive sensor areas are adapted to, upon relative rotational movement between the first and second sensor part, provide electrical signals being indicative of the relative rotational position between the first and second sensor part, and wherein the processor unit is adapted to receive and process said signals to determine the amount of relative rotations.
The rotation preventing engagement between the first sensor and the piston or housing and between the second sensor part and the piston rod may be based on any suitable friction- or form-based engagement. In particular, the engagement to the elastomeric piston could be based on gluing or by means of protrusions on the module either penetrating into the piston or providing sufficient friction to prevent relative rotation between the piston and module.
Based on the above, a cost-effective, reliable and compact module is provided enabling the delivery device to accurately detect dosage data (size and time). and further communicate these data to an external device without the need for an add-on accessory attached to the pen device. Further, a module is provided where the integration into the device requires very little modification of the device.
Though the module due to its compact, inexpensive construction is intended for use in a disposable device, it should be understood that it also can be implemented in a durable and more expensive pen drug delivery device.
As used herein, the term “drug” is meant to encompass medicine formulation capable of being passed through a delivery means such as a cannula or hollow needle in a controlled manner, such as a liquid, solution, gel or fine suspension, and containing one or more drug agents. The drug may be a single drug compound or a premixed or co-formulated multiple drug compounds drug agent from a single reservoir. Representative drugs include pharmaceuticals such as peptides (e.g. insulins, insulin containing drugs, GLP-1 containing drugs as well as derivatives thereof), proteins, and hormones, biologically derived or active agents, hormonal and gene based agents, nutritional formulas and other substances in both solid (dispensed) or liquid form. In the description of the exemplary embodiment reference will be made to the use of insulin and GLP-1 containing drugs, this including analogues thereof as well as combinations with one or more other drugs. Further, the terms “distal” and “proximal” denote positions at, or directions along, a drug delivery device, a drug reservoir, or a needle unit, where “distal” refers to the drug outlet end and “proximal” refers to the end opposite the drug outlet end.
Some embodiments of the invention are summarised in the following:
Embodiment 1: A method of assembling a prefilled drug delivery device with an electronic rotary dosage sensing module for sensing the amount of drug being expelled from the delivery device, the device comprising a preassembled dosage engine part with a dose setting and expelling mechanism and a preassembled drug holding part with a drug-filled cartridge having a displaceable piston and an outlet, the dose expelling mechanism having a piston rod with a distal tip part to be rotationally and axially advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet, when the delivery device is assembled, said electronic sensing module comprising;
Embodiment 2: A method according to embodiment 1, wherein the distal tip part of the piston comprises a central bore and a circumferential portion having one or more deflectable gripping arms, and wherein the second sensor part comprises a cylindrical part extending through an opening in the first housing part and having one or more protrusions located on an outer surface, and wherein step a) comprises moving said cylindrical part into said bore, whereby the deflectable gripping arms deflect over said protrusions and subsequently grip around said protrusions and provide a locked interconnection between the second sensor part and piston rod not allowing any relative rotation between the sensor part and the piston rod.
Embodiment 3: A method according to embodiment 1 or 2, wherein the first housing part, power source unit retaining means, the processor unit, and the sensor unit is preassembled before performing step a).
Embodiment 4: A method according to any of embodiments 1-3, wherein the step of positioning the power source unit comprises moving the power source unit into the retaining means in a direction perpendicular to the axis of rotation of the piston rod.
Embodiment 5: A method according to any of embodiments 1-3, wherein the step of positioning the power source unit comprises moving the power source unit into the retaining means in a direction parallel to the axis of rotation of the piston rod.
Embodiment 6: A method according to any of the preceding embodiments, wherein the power source unit is a coin cell battery.
Embodiment 7: An electronic rotary dosage sensing module assembly for a prefilled drug delivery device comprising a dosage engine part with a dose setting and expelling mechanism and a drug holding part with a drug-filled cartridge having a displaceable piston and an outlet, the dose expelling mechanism having a piston rod with a distal tip part to be rotationally and axially advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet, said module comprising;
Embodiment 8: An electronic rotary dosage sensing module assembly for a prefilled drug delivery device comprising a dosage engine part with a dose setting and expelling mechanism and a drug holding part with a drug-filled cartridge having a displaceable piston and an outlet, the dose expelling mechanism having a piston rod with a distal tip part to be rotationally and axially advanced in a direction towards said piston to displace the piston and thereby expel a dosage of drug from the cartridge through the outlet, said module comprising;
Embodiment 9: An assembly according to embodiment 7 or 8, wherein the second sensor part is adapted to be directly or indirectly attached to said distal tip part of the piston rod.
Embodiment 10: An assembly according to any of embodiments 7-9, wherein the distal tip part of the piston comprises a central bore and a circumferential portion having one or more deflectable gripping arms, and wherein the second sensor part comprises a cylindrical part extending through an opening in the first housing part and having one or more protrusions located on an outer surface, and where said cylindrical part is adapted to be moved into said bore, so that the deflectable gripping arms deflect over said protrusions and subsequently grip around said protrusions to provide a locked connection between the second sensor part and piston rod not allowing any relative rotation between the sensor part and piston rod.
Embodiment 11: An assembly according to any of embodiments 7-10 and assembled together with a drug delivery device by a method according to any of embodiments 1-6.
In the following the invention will be further described with reference to the drawings, wherein
Referring to
More specifically, the pen device comprises a main part having a proximal body or drive assembly portion with a housing 110 in which a drug expelling mechanism is arranged or integrated, and a distal cartridge holder portion 120 holding a drug-filled transparent cartridge 130 having a displaceable piston (not shown) and distal needle-penetrable septum 140. The cartridge holder has openings 150 allowing a portion of the cartridge to be inspected. The cartridge may for example contain an insulin, GLP-1 or growth hormone formulation. A proximal-most rotatable dose ring member 160 serves to manually set a desired dose of drug shown in display window 170 and which can then be expelled when the release button 180 is actuated.
Depending on the type of expelling mechanism embodied in the drug delivery device, the expelling mechanism may comprise a spring, as in the pen shown in
The second sensor part 220 (the “wiper”) is rotationally locked to a tip part of the piston rod 201. As the first 210 and second sensor part 220 can rotate relative to the each other and as the piston 202 doesn't rotate during dose expelling, a rotational movement of the piston rod 201 during dose expelling will cause the second sensor part 220 to rotate relative to the first sensor part 210.
In
The second sensor part 220 has individual contact structures 308 in the form of three flexible arms adapted to deflect the different conductive sensor areas 305 of the first sensor part 210 into contact with a surface 306 of the battery (e.g. the (−) terminal) and thereby close the electrical circuit between the (−) terminal and processor unit 207 to provide an electrical signal, when the first 210 and second sensor part 220 rotate relative to each other.
The first sensor part 210, when placed in the pen, will via the housing part 204 be in a non-rotational engagement with the piston 202 of the cartridge 203.
Conductor(s) on the flexible PCB sheet may provide connection allowing the battery 206 to deliver a continuous low “sleep current” to the processor unit 207 in order for the processor unit to keep track of time however it may first be activated when the module is used for the first time.
The flexible printed circuit board sheet may also comprise means for wireless communication (see e.g.
The sensor areas 305 and the structures 308 are configured to create a pattern of contact positions indicative of a rotational position between the first and second sensor part, and the processor unit 207 can then process the electrical signals received indicative of the relative rotational position between the first and second sensor part to determine the amount of relative rotation and based thereon calculate a corresponding expelled dose and store this data.
In another embodiment shown in
The battery 410 is intended to be positioned in the space 413 in the folded flexible printed circuit board sheet 400. A housing 415 is provided to house the flexible printed circuit board sheet 400, the battery 410 and the processor unit 411, the housing being arranged such that the surface 416 is positioned in the space 414 and thus supports the first surface of the first sensor part 401 underneath. The small conductive sensor areas of the first sensor part will be connected to the processor unit and the large sensor areas will be connected to (−) terminal of the power battery 410. In this embodiment the second sensor part may be connected to the (−) terminal but not necessarily.
The second sensor part 407 is adapted to engage the piston rod 409 such that no rotation between the second sensor part and piston rod is not possible, and the housing 415, including the flexible printed circuit board sheet 400, battery 410 and processor unit 411, is adapted to engage the piston of the drug cartridge (not shown), such that no rotation between the housing and thus first sensor part 401 is possible.
When the first 410 and second sensor part 407 rotate relative to each other the contact structures 408 electrically connect the different conductive sensor areas 405 of the first sensor part and thereby close the electrical circuit between the (−) terminal and processor unit 411 to provide an electrical signal to the processor unit being indicative of the rotational position between the first and second sensor part, and the processor unit is adapted to process the signals to determine the amount of relative rotations and thereby calculate the amount of expelled dosage size.
In
Spacers 618, 619 are arranged to provide axial spacing between the conductive sensor areas 605 and a second surface area, in this embodiment a surface 609 of the battery 610, see
When the sensor unit is an inactive state, only the support surfaces 622 of the arms will engage the flexible printed circuit board sheet on the side opposite to side facing surface areas 609 of the battery, as shown in the leftmost drawing of
The second sensor part 607 has attachment means 624 allowing the second sensor part to be attached, either directly or indirectly, to the piston rod such that no relative rotation between the second sensor part and the piston rod is possible.
(+) and (−) terminals 620, 621 are provided on the flexible printed circuit board sheet for connection to the terminals of the battery 610.
The module is positioned such that the second sensor part 607 of the sensor unit is engaged and rotationally locked to a drive tube 705 via the element 706, the drive tube being in engagement with the piston rod 750 to rotationally drive the piston rod during dose expelling, meaning that the second sensor part 607 is indirectly fixed to the piston rod and will follow the rotation thereof during dose expelling. The first sensor part 601 of the sensor unit is arranged axially offset to the second sensor part 607 and perpendicularly relative to the axis of rotation and is fixed in the pen such that it doesn't rotate during dose expelling.
The flexible printed circuit board sheet 600 is folded around the battery 610. The pen with the module as shown in
To expel the set dose, the injection button 760 is pushed axially in the direction 770, whereby the first sensor part 601 together with battery etc. is moved axially towards the second sensor part 607. When the injection button is moved the distance 761, the spring hasn't been released yet, but the structure 608 have deflected a respective conductive sensor area 605 into connection with the surface 606 to connect it to the electrical circuit and the sensor unit is then activated (“dose expelling mode”) and the processor unit will get signals indicative of the start position of the sensor unit. When the injection button is pushed further axially, both the injection button 760 and the part 763 will move together the distance 762 and the spring 740 will be released. Now the drive tube 706 and accordingly the piston rod 750 will start rotating and advance axially toward the piston 720 to expel the dose. As the second sensor part 607 is rotationally locked to the piston rod via the drive tube, it will start rotating together with piston rod and the structures 608 will then in turn deflect respective conductive sensor areas 605 into connection with the surface 609 of the battery. The established connections generate an electrical signal, as explained above, to the processor unit, said signal being indicative of the relative rotational position between the first and second sensor part.
In
In
The code pattern for the embodiments of the module shown in the figures is based on a “resolution” of 15 degrees of rotations between each connection, which for a given drug formulation and delivery device combination may correspond to 1 unit (IU) of insulin, i.e. one full 360 degrees revolution of the piston rod corresponds to 24 units (IU). As can be seen in the
Further, the use of only three arms has the advantage that the friction force between the first and second sensor part is kept low (the fewer arms the lower friction) and that the torque is the same on all three arms, as long as the arms are made of flexible material.
For a drug formulation having the double concentration a 7.5 degree rotary “resolution” would be necessary to register dose steps corresponding to 1 IU of insulin, unless each dose step equals 2 IU and instead of 1 IU.
As a given dose of drug, especially if large, may be divided and injected with a given pause, the module may be programmed to log two dose amounts expelled within a given time window, e.g. 15 minutes, as one dose.
An exploded view of a rotary sensor module according to the invention is shown in
The rotary sensor module further comprises a second sensor part 1120 oppositely arranged to said surface 1122 of the first sensor part 1110 and mounted to the piston rod 201 at its distal tip part 1125 to follow the rotation of the piston rod during dose expelling. The piston rod has a centre axis A, 1128, around which is rotates during dose expelling.
The second sensor part has contact structures 1108 in the form of two electrically connected flexible arms that are connected to the (−) terminal of the battery and adapted to engage and electrically connect different individual electrically conductive sensor areas 1105 of the first sensor part, upon relative rotational movement between the first and second sensor part, to the processor unit to thereby close an electrical circuit between the (−) and the processor unit. Each of these electrical connections generates an electrical signal to a processor unit being indicative of the rotational position between the first and second sensor part. See more detailed description of this in connection with
A centering element 1126 is provided between the first and second sensor part for centering the piston rod and thereby the second sensor part 1120 in relation to the first sensor part 1110, which is essential for the rotary sensor to measure the correct amount of relative rotations between the piston rod and piston. The centering element 1126 comprises a bearing cup part 1127 with a centre axis C, 1129, for maintaining the distal part of piston rod, in this situation a part of the second sensor part 1120, in a position where the axis' 1121, 1128 are coinciding.
To provide a proper centering, the bearing cup part 1127 can have different forms as depicted in
In
During dose expelling the piston rod is rotated and advanced axially in the direction of the piston in order to advance the piston forward in the cartridge. Thus, the piston rod will exert an axial force on the piston via the rotary sensor module and due to the centering element the torque required to rotate the piston rod in relation to the piston is minimised, as the centering element ensures that the mechanical contact between the parts rotating relative to each other is kept at the axis of rotation. The torque required can be even more minimised depending on the design of the centering element, see
The centering element may be fixedly attached to the first sensor part by different appropriate means, such as by riveting, soldering or gluing. If soldered, the centering element can function as an electrical contact between e.g. the (−) terminal and the second sensor part, as shown and described in
In
In
In order to save power, the processor unit may, immediately after registering the readout of a sensor area (ENC1, ENC2, ENC3, ENC4), switch the electrical circuit “off” for that specific sensor area. This is shown in the diagram in
The module further comprises a second stationary sensor part 1510 comprising a flexible printed circuit board sheet 1500 on which are located contact structures 1508 extending parallel to the axis of rotation of the piston rod. The flexible sheet 1500 is folded around a cell coin battery 1506 (see
A centering element 1526 is located between the two sensor parts and is made of conductive material. When assembled (see
The module preferably also comprise a communication unit to wirelessly communicate data (dose size, timestamp) from the module to an external device.
As the piston rod rotates during dose expelling, the contact structures 1508 (four in total) will electrically connect to different individual electrically conductive sensor areas 1505. In
A first sensor part 1714 is fixed in the first housing part via the supporting structure 1715 such that no relative rotation between the first sensor part and the housing is possible. The first sensor part has a flexible printed circuit board sheet having a first surface supported by the structure 1715 on which is disposed a plurality of individual electrically conductive sensor areas arranged in a pattern (not shown in
Designing the sensing module as shown in
For any of the described embodiments above the conductive sensor areas and the contact structures together are configured to create a code pattern of contact positions (encoder) indicative of the rotational positions between the first and second sensor part. The indexing code pattern may be based on a Gray code system or quadrature code system or any other relevant system. The Gray code could e.g. be a 4 bit 72 increment encoder system, where the pattern repeats 9 times for each 360 degrees revolution.
In the above description of exemplary embodiments, the different structures and means providing the described functionality for the different components have been described to a degree to which the concept of the present invention will be apparent to the skilled reader. The detailed construction and specification for the different components are considered the object of a normal design procedure performed by the skilled person along the lines set out in the present specification.
| Number | Date | Country | Kind |
|---|---|---|---|
| 18184903.5 | Jul 2018 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/068253 | 7/8/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62696108 | Jul 2018 | US |
