Power unit of drug delivery device

Abstract

The power unit (2) of the medication delivery device (1) is provided and includes a pusher element (241) for pushing the plunger (32), a drive unit (23) having a drive nut (234) and a stepper motor (231), a controller (222) for controlling the stepper motor (231), and an encoder (25) for determining the displacement position of the pusher element (241). The drive nut (234) is adapted to convert the rotational movement of a rotor (233) of the stepper motor (231) into a proximal displacement of the pusher element (241). The drive unit (23) is configured as a direct drive, i.e., the drive nut (234) rotates at the same speed as the rotor (233), and the rotational movement of the drive nut (234) is directly converted into a displacement of the pusher element. The controller (222) is configured to monitor the back electromotive force of the stepper motor (231).

Description

[Technical Field]

[0001] The present invention generally relates to a power unit for a medication delivery device. The medication delivery device may in particular be an electromechanical injector having a power unit to which a medication unit having a medication container and an injection needle can be releasably attached. The present invention also relates to a medication unit and a medication delivery device having such a power unit and such a medication unit. [Background technology]

[0002] Medication delivery devices in the form of automatic injectors have several advantages over manual injectors. Not only do they make medication administration much more comfortable for the patient, but they are also safer in terms of operator error. For example, the insertion of the needle into the patient's skin and the administration of the medication can be automated, thereby, among other things, avoiding underdosing. In some of these devices, the energy for delivering the fluid medication is provided by a spring. Another category relates to electromechanical injectors, in which the energy for expelling the medication is provided by a motor, which is usually an electric motor.

[0003] Medication delivery devices in the form of electromechanical injection devices typically comprise a power unit to which a medication unit is releasably attached. The medication unit includes a medication container for storing the medication and a medication delivery element, such as a needle, through which the medication can be injected into a patient. To expel the medication from the medication container through the needle, a pusher element of the power unit is displaced proximally into the medication container of the medication unit, where it engages a plunger and pushes the plunger proximally toward the needle. An electric motor is typically used in these devices to displace the pusher element.

[0004] In most state-of-the-art electromechanical medication injectors, the entire contents of the medication container are expelled upon actuation of the injection. Therefore, a pusher element is advanced by a motor until the plunger reaches the proximal end of the medication container, i.e., until the container is empty. In these devices, the displacement distance of the pusher element to empty the entire medication container is controlled, for example, by a mechanical switch that stops the motor when the pusher element has been displaced a certain distance. Such full-dose delivery devices have the inherent disadvantage that the dose to be injected is fixed and cannot be adjusted. Furthermore, because full-dose delivery devices expel all or nearly all of the medication contents of the medication unit, the medication unit is typically not reusable and must be discarded after a single use.

[0005] Other electromechanical injectors are known that allow for the delivery of a single dose of fluid medication, i.e., each injection delivers only a portion of the contents of the medication container, but not the entirety. To this end, the steps taken by a stepper motor during an injection can be counted in order to stop the motor after a predetermined dose of medication has been released. Thus, the syringe can be reused for a certain number of injections, with only a certain amount (dose) of medication being injected each time.

[0006] A problem with counting stepper motor steps to determine drug dosage is that steps may be missed if, for example, an occlusion occurs in the fluid path of the device.

[0007] A reusable automatic injector for administering a dose of a fluid medication is disclosed, for example, in EP 2654843 (B1). This device includes an encoder sensor for determining the initial position of the plunger of the reusable medication unit. The encoder sensor is also used to detect motor stall.

[0008] US Patent Application Publication No. 2022 / 0257864 A1 discloses an auto-injector delivery device configured with a stall and endpoint detection algorithm based on an encoder coupled to a motor.

[0009] U.S. Patent Application Publication No. 2013 / 0253420 A1 relates to an infusion pump with pulse-width modulated (PWM) motor control. The displacement of the plunger is measured by means of a rotary encoder to determine the number of missed steps of the motor. In this way, blockages in the fluid path of the device can be detected.

[0010] Another prior art document that discloses a medication delivery device with an encoder for detecting motor stall is US Patent Application Publication No. 2014 / 0114277(A1), in which motor stall detection is further used to detect the initial position of the plunger.

[0011] U.S. Patent No. 9,216,249 (B2) discloses plunger contact detection using an encoder for an infusion pump. To this end, a stepper motor is operated with limited power so that the motor pushes the plunger with as little force as possible. Contact with the plunger is detected based on motor stall detection by the encoder.

[0012] EP 4059547 A1 discloses an injection device in which an instantaneous motor value is compared with a reference motor value in order to detect when a dosing member, which is advanced by a motor via a gear, comes into contact with a reservoir element, and it is proposed to use the position value of the movable drive member as the instantaneous motor value, or to use the back electromotive force value.

[0013] Detection of the initial plunger position based on detecting motor stall by means of an encoder has the drawback that the motor power must be significantly reduced to avoid pushing the plunger too far forward, and even then some displacement of the plunger is almost unavoidable, resulting in a loss of dose accuracy. Summary of the Invention

[0014] It is an object of the present invention to provide a power unit for an electromechanical drug delivery device that allows for the administration of a predetermined dose with particular accuracy and reliability.

[0015] This object is solved by a power unit as claimed in claim 1. A medication unit adapted to be used with such a power unit is set out in claim 14. A medication delivery device comprising such a power unit is set out in claim 15. Further preferred embodiments are set out in the dependent claims.

[0016] The present invention therefore relates to a power unit of a medication delivery device, in particular an automatic injector for delivering medication from a medication container to a human or animal patient, said power unit comprising: a pusher element adapted to engage and push the plunger proximally to expel the medicament from the medication delivery device; a drive unit including a drive nut and a stepper motor having a rotor and a stator, the drive nut adapted to translate rotational movement of the rotor into proximal displacement of the pusher element; a controller for controlling the stepping motor; and an encoder for determining the displacement position of the pusher element.

[0017] The drive unit is configured as a direct drive such that the drive nut rotates at the same speed as the rotor of the stepper motor and the rotational movement of the drive nut is directly translated into displacement of the pusher element. The controller is configured to monitor the back electromotive force of the stepper motor.

[0018] Combining the determination of the displacement position of the pusher element using an encoder with monitoring the back electromotive force of the stepper motor allows for particularly reliable and accurate volumetric dosing. By monitoring the back electromotive force, the controller has the ability to sense the force applied to the stepper motor, which is used not only to detect the plunger position and therefore the starting point of volumetric dosing before injection, but also to measure the counter pressure acting on the plunger during injection. By using the back electromotive force, detection of the plunger position can be achieved while minimizing plunger displacement. Nevertheless, if some plunger displacement occurs, this can be detected by the encoder to still enable accurate volumetric dosing. The counter pressure generated during injection can be an important indicator of, for example, the viscosity of the medication, partial or complete blockage of the fluid path, or improper needle insertion at the injection site. The use of an encoder not only allows knowledge of the current state of the motor, but also allows for direct information on the position and displacement of the plunger to be obtained. Thus, the correct administration of a particular dose can be confirmed in a particularly reliable and consistent manner. The use of an encoder, combined with back-EMF monitoring, also allows for detection and recovery from stall of the stepper motor during injection. This ability to recover from a stall or step loss and continue to inject an accurate dose also allows the stepper motor to operate at equally high loads. As a result, the present invention is not only well suited for auto-injectors with volumetric dosing capabilities, but also for electromechanical drug delivery devices in general, i.e., total dose ejection devices.

[0019] The use of a direct drive configuration, i.e., a gearless drive unit, further enhances the significance of measurement data such as back EMF, counting of motor steps, and encoder measured data in terms of ease of combination of such data by the controller to achieve accurate and reliable dose dosing. By providing a direct drive, the counted motor steps, encoder measured data, and measured back EMF are more closely related to each other, since there is no need to consider backlash in the gear unit.

[0020] The provision of a stepper motor allows for specific and precise displacement of the pusher element over a predetermined distance, and the use of a stepper motor allows for counting steps during displacement of the pusher element when trying to find the start point of a dose administration or during an injection, and relating the counted steps to encoder measurements, for example, to detect motor stall.

[0021] In this disclosure, when the term "distal direction" is used, it refers to the direction away from the dose delivery site during use of the drug delivery device. When the term "distal part / end" is used, it refers to the part / end of the delivery device, or part / end of a member thereof, that is located furthest from the dose or drug delivery site during use of the drug delivery device. Correspondingly, when the term "proximal direction" is used, it refers to the direction towards the dose delivery site during use of the drug delivery device. When the term "proximal part / end" is used, it refers to the part / end of the delivery device, or part / end of a member thereof, that is located nearest to the dose delivery site during use of the drug delivery device.

[0022] Furthermore, unless otherwise indicated, the terms "longitudinal," "longitudinally," "axially," and "axial" refer to a direction extending along a device or its components from the proximal end to the distal end, typically in the direction of the longest extension of the device and / or component.

[0023] Similarly, the terms "transverse," "transversal," and "transversally" refer to a direction generally perpendicular to the longitudinal direction.

[0024] Preferably, the power unit forms a reusable component of the medication delivery device, which is used for administering the medication in combination with a medication unit comprising a medication container for storing the medication to be injected and a medication delivery element, such as a needle, through which the medication can be injected into the patient's body. The medication unit, which is typically releasably attachable to the power unit, can be designed for single use only or for reuse, in particular for administering multiple doses. A plunger is typically located in the medication container for being engaged by a pusher element after attaching the medication unit to the power unit.

[0025] The drug delivery device can be, for example, an auto-injector, a pen-type injector, or a body-worn device. The drug delivery element is typically a cannula or hollow needle, also referred to as a needle for short. The drug delivery device is preferably adapted to be inserted proximal end first into the patient's skin for subcutaneous injection of the drug into a desired location within the patient's body. The drug is typically delivered from the drug container to the patient by advancing a plunger inside the container in a proximal direction. The advancement of the plunger is accomplished by a stepper motor.

[0026] The drug delivery devices described herein can be used to treat and / or prevent one or more of many different types of disorders.

[0027] Exemplary disorders include, but are not limited to, rheumatoid arthritis, inflammatory bowel disease (e.g., Crohn's disease and ulcerative colitis), hypercholesterolemia, diabetes (e.g., type 2 diabetes), psoriasis, migraines, multiple sclerosis, anemia, lupus, atopic dermatitis, asthma, nasal polyps, acute hypoglycemia, obesity, anaphylaxis, and allergies. Exemplary types of drugs that can be included in the drug delivery devices described herein include, but are not limited to, antibodies, proteins, fusion proteins, peptibodies, polypeptides, pegylated proteins, protein fragments, protein analogs, protein variants, protein precursors, and / or protein derivatives. Exemplary drugs that may be included in the drug delivery devices described herein include etanercept (rheumatoid arthritis, inflammatory bowel disease (such as Crohn's disease and ulcerative colitis)), evolocumab (hypercholesterolemia), exenatide (type 2 diabetes), secukinumab (psoriasis), erenumab (migraines), alirocumab (rheumatoid arthritis), methotrexate (amethopterin) (rheumatoid arthritis), tocilizumab (rheumatoid arthritis), interferon beta-1a (multiple sclerosis), sumatriptan (migraines), adalimumab (rheumatoid arthritis), darbecause Drug delivery devices described herein include, but are not limited to (and are not limited to) the examples of relevant disorders in parentheses: poietin alfa (anemia), belimumab (lupus), peginterferon beta-1a' (multiple sclerosis), sarilumab (rheumatoid arthritis), semaglutide (type 2 diabetes, obesity), dupilumab (atopic dermatitis, asthma, nasal polyps, allergies), glucagon (acute hypoglycemia), epinephrine (anaphylaxis), insulin (diabetes), atropine, and vedolizumab (inflammatory bowel disease (e.g., Crohn's disease and ulcerative colitis)). Pharmaceutical formulations comprising, but not limited to, any of the agents described herein, for example, a pharmaceutical formulation comprising an agent listed herein (or a pharmaceutically acceptable salt thereof) and a pharmaceutically acceptable carrier, are also contemplated for use in the drug delivery devices described herein. Pharmaceutical formulations containing the agents named herein (or pharmaceutically acceptable salts of the agents) may contain one or more other active ingredients, or may be the only active ingredient present.

[0028] Further exemplary disorders include dyslipidemia, cardiovascular disease, diabetes (e.g., type 1 diabetes or type 2 diabetes), psoriasis, psoriatic arthritis, spondyloarthritis, hidradenitis suppurativa, Sjogren's syndrome, migraine, cluster headache, multiple sclerosis, neuromyelitis optica spectrum disorder, anemia, thalassemia, paroxysmal nocturnal hemoglobinuria, hemolytic anemia, hereditary angioedema, systemic lupus erythematosus, lupus nephritis, myasthenia gravis, Behcet's disease, hemophagocytic syndrome, atopic dermatitis, retinal disease (e.g., age-related macular degeneration, diabetic macular edema), uveitis, infection, bone disease (e.g., osteoporosis, osteopenia), asthma, chronic obstructive pulmonary disease, thyroid eye disease, nasal polyps, transplant, acute hypoglycemia, obesity, anaphylaxis, allergy, sickle cell disease, Alzheimer's disease, Parkinson's disease, dementia with Lewy bodies, systemic infusion reactions, immunoglobulin E (IGE), ... These include, but are not limited to, IgE-mediated hypersensitivity reactions, cytokine release syndrome, immune deficiencies (e.g., primary immune deficiency, chronic inflammatory demyelinating polyneuropathy), enzyme deficiencies (e.g., Pompe disease, Fabry disease, Gaucher disease), growth factor deficiencies, hormone deficiencies, coagulation disorders (e.g., hemophilia, von Willebrand disease, factor V Leiden), and cancer.

[0029] The power unit preferably comprises at least one primary energy source, such as a battery, in particular a researchable battery, for powering the stepper motor and advantageously also the controller. In addition to the above-mentioned energy sources, the power unit preferably comprises at least one secondary energy source, such as a button cell, for supplying energy to a real-time clock (RTC) when the primary energy source is discharged or even during replacement.

[0030] The power unit preferably comprises one or more signaling elements for providing information to the user regarding the status of the device. The signaling elements preferably include a vibrator for providing tactile feedback. Alternatively or additional signaling elements may be provided, for example, one or more light emitting diodes (LEDs) and a sound generator. The LEDs may be arranged to form a progress bar, for example, to indicate the progress of administration of the dose currently being injected and / or the progress of the entire treatment, including multiple doses to be injected.

[0031] The pusher element preferably has the form of a rod disposed on a major longitudinal axis of the power unit extending from the distal end to the proximal end of the power unit. The pusher element may have an external thread for engagement by the internal thread of the drive nut. The internal thread of the drive nut, if provided, preferably serves to translate rotational movement of the rotor into displacement of the pusher element. To prevent the pusher element from rotating with the drive nut, anti-rotation guidance is preferably provided, which guidance allows the pusher element to be displaced but not rotated relative to the drive nut.

[0032] The stepper motor preferably comprises a hollow motor shaft through which the pusher element extends, and the drive nut is preferably fixedly attached to or integrally formed with the hollow shaft.

[0033] The controller preferably has the form of one or more microchips that are part of a printed circuit board (PCB) advantageously located within the housing of the power unit. The one or more microchips preferably comprise at least a computing unit and a memory unit in which instructions are stored that are executed by the computing unit during use of the device. The controller is specifically considered to be configured according to the instructions stored in the memory unit.

[0034] In a particularly preferred embodiment, the controller is configured to detect contact between the plunger and the pusher element based on monitoring the back EMF.

[0035] As long as the pusher element is freely displaceable and no blockage of the drive unit occurs, the back electromotive force (back EMF) is typically proportional to the rotational speed of the rotor of the stepper motor, which means that the motor speed can be measured indirectly via the back EMF. Essentially, the back EMF is determined by measuring the electrical energy flowing into the stepper motor and the electrical energy flowing out of the motor. The difference between the two energies, i.e., the back EMF, provides an indication of the mechanical load taken from the motor. In other words, it measures what portion of the energy supplied to the stepper motor returns to the power supply (or energy source). This reserve energy is a measure of the mechanical load applied to the stepper motor. If it reaches zero, there is no reserve energy left and the motor can stall.

[0036] To reliably determine the counterforce acting on the pusher element during proximal (or distal) displacement, the controller is preferably configured to detect a change in the relationship between the back EMF and a first reference value. The first reference value preferably has the form of a threshold, and the controller is configured to detect whether the back EMF falls below or exceeds the threshold. Thus, the controller is specifically configured to detect a change in the back EMF while the threshold remains constant. The detected change in the back EMF can be specifically used by the controller to determine that the pusher element has contacted the plunger. The second reference value can be used by the controller to detect stall of the stepper motor, i.e., when the measured back EMA exceeds the second reference value. The second reference value can also be considered a threshold and may be the same as the first reference value, or may be lower or higher than it.

[0037] The controller is preferably configured to perform device calibration to set the first and / or second reference values. Calibration is preferably initiated by attaching the medication unit to the power unit. The reference values ​​are preferably adjusted depending on the amount of current supplied to the stepper motor to displace the pusher element, the rotation frequency of the rotor of the stepper motor, and / or the displacement speed of the pusher element. Calibration can be achieved, for example, by performing a test displacement of the pusher element at a safe distance from the plunger and considering the electrical energy supplied to the stepper motor and the corresponding measured back EMF. Additionally or alternatively, the reference values ​​can be set to predetermined values ​​during calibration, which can be selected, for example, based on information about the attached medication unit. The information can be obtained, for example, from detection of the type of attached medication unit or from user input, for example, using a separate wired or wireless device. The reference values ​​can be set by the controller, for example, using a look-up table stored in the memory unit.

[0038] In a particularly preferred embodiment, the controller is configured to relate the monitored back EMF to the current supplied to the stepper motor, in this way contact between the pusher element and the plunger or stalling of the motor can be detected in a particularly reliable manner.

[0039] The controller is preferably configured to correlate the monitored back EMF with the displacement position of the pusher element as determined by the encoder. For example, information about the displacement position of the pusher element obtained from the encoder can be used by the controller to determine whether a sudden change in back EMF is due to contact between the pusher element and the plunger or, instead, due to stalling of the stepper motor. By correlating the monitored back EMF with the encoder displacement information, it is also possible to accurately determine the position of the plunger before and after contact by the pusher element. Furthermore, in this way, it is possible to accurately determine the position of the plunger just before stalling of the stepper motor during an injection, thereby enabling recovery from stall.

[0040] To determine the displacement position of the pusher element, the encoder preferably measures the rotational position of the drive nut and / or the displacement position of the pusher element. Measuring the displacement position of the pusher element along the main longitudinal axis of the device provides more direct, and therefore particularly reliable, information about the state of the pusher element, while measuring the rotational position of the drive nut is typically simpler to implement yet still sufficiently reliable.

[0041] The encoder preferably comprises an optical sensor, in particular a photoelectric sensor, preferably in the form of a photointerrupter, which typically only measures discrete values ​​but is highly accurate and reliable.

[0042] To achieve direct measurement of the rotational state of the drive nut, the encoder preferably comprises a disc attached to or made integral with the drive nut, the disc advantageously including a portion that is identifiable by an optical sensor of the encoder.

[0043] The controller is preferably configured to stop the stepper motor when a predetermined displacement position of the pusher element as determined by the encoder is reached, in particular during medication injection. By measuring the displacement position of the pusher element by means of an encoder, very reliable and accurate dose dosing can be achieved.

[0044] In a preferred embodiment, the controller is configured to receive a volumetric dosing instruction, preferably from a drug unit of the drug delivery device or from a user, and to control the stepper motor so that the pusher element is moved to a displacement position corresponding to the received volumetric dosing instruction and / or so that the pusher element is displaced proximally by a displacement distance corresponding to the received volumetric dosing instruction.

[0045] The power unit preferably comprises an RFID (radio frequency identification) unit and / or a wireless receiving unit for receiving volumetric dosing instructions. The RFID unit can be adapted to read, for example, an RFID tag of the medication unit, which provides information about the volumetric dosing of medication stored in the medication unit. The volumetric dosing instructions typically include information about the amount of medication to be injected. The volumetric dosing instructions can also include information about the status of the medication unit, for example, information about the actual position of the plunger taking into account previous dose administrations. By using the plunger position information, faster and more accurate contact of the plunger by the pusher element can be achieved. Alternatively or additionally, the RFID unit serves, for example, to identify the medication stored in the medication unit and / or the source of the medication unit.

[0046] The controller is preferably configured to detect the removal of a closure cap from a medication unit of the medication delivery device. The closure cap typically serves to close, specifically seal, the injection needle of the medication unit. Removal of the closure cap prepares the medication delivery device for injection by the user. The controller is preferably configured to enter a pre-delay phase upon detecting the removal of the closure cap, during which the stepper motor remains idle. The pre-delay phase can last, for example, 1 to 10 seconds; during this phase, the pusher element is not displaced by the stepper motor and remains in its position. The pre-delay serves to equalize pressure within the medication container after the plunger contacts and engages the pusher element. In this way, dose accuracy can be significantly improved. The user can be notified, for example, by a visual, auditory, and / or tactile signal, when the pre-delay period has expired. The injection can then begin.

[0047] Preferably, the controller is configured to enter a post-delay phase when the proximal displacement of the pusher element is complete, i.e., after the dose administration is completed. During the post-delay phase, the stepper motor remains idle, i.e., the pusher element is not displaced. The pre-delay phase, which may last for example 1 to 10 seconds, is provided to allow pressure within the medication container to equalize, thereby significantly improving dose accuracy for subsequent further dose injections.

[0048] In a particularly preferred embodiment, the power unit is adapted to receive a drug unit of a drug delivery device by means of releasable attachment, the drug unit comprising a drug container for storing the drug to be injected and a drug delivery element having a proximal end through which the drug can be delivered to the patient.

[0049] The present invention also relates to a medication unit adapted to be received by a power unit comprising an RFID unit as further described above, the medication unit comprising an RFID tag adapted to store volumetric dosing instructions readable by the RFID unit of the power unit, the controller of the power unit preferably being configured to cause the medication delivery device to release an amount of medication from the medication unit in accordance with the volumetric dosing instructions received from the RFID tag.

[0050] Furthermore, the present invention relates to a drug delivery device comprising a power unit as described and a drug unit, preferably a drug unit as described.

[0051] Exemplary types of drugs or agents that may be included in the delivery devices described herein include, but are not limited to, small molecules, hormones, cytokines, blood products, enzymes, vaccines, anticoagulants, immunosuppressants, antibodies, antibody-drug conjugates, neutralizing antibodies, antagonists, radioligand therapy, radioisotopes and / or nuclear agents, diagnostic agents, bispecific antibodies, proteins, fusion proteins, peptibodies, polypeptides, pegylated proteins, protein fragments, nucleotides, protein analogs, protein variants, protein precursors, protein derivatives, chimeric antigen receptor T-cell therapy, cell or gene therapy, oncolytic viruses, or immunotherapy.

[0052] Exemplary drugs that may be included in the delivery devices described herein include, but are not limited to, immuno-oncology or bio-oncology agents such as immune checkpoints, cytokines, chemokines, differentiation clusters, interleukins, integrins, growth factors, clotting factors, enzymes, enzyme inhibitors, retinoids, steroids, signaling proteins, pro-apoptotic proteins, anti-apoptotic proteins, T cell receptors, B cell receptors, or costimulatory proteins.

[0053] Exemplary drugs that may be included in the delivery devices described herein include modulators of the human epidermal growth factor receptor 2 (HER-2) receptor, interleukin (IL) modulators, interferon (IFN) modulators, complement modulators, glucagon-like peptide-1 (GLP-1) modulators, glucose-dependent insulinotropic polypeptide (GIP) modulators, cluster of differentiation 38 (CD38) modulators, cluster of differentiation 22 (CD22) modulators, C1 esterase modulators, bradykinin modulators, CC chemokine receptor type 4 (CCR4) modulators, vascular endothelial growth factor (VEGF) modulators, B-cell activating factor (B-CFR) modulators, and the like. Modulators of the following molecules are also available: modulators of BAFF (basal antigen receptor), P-selectin modulators, modulators of neonatal Fc receptor (FcRn), modulators of calcitonin gene-related peptide (CGRP), modulators of epidermal growth factor receptor (EGFR), modulators of cluster of differentiation 79B (CD79B), modulators of tumor-associated calcium signal transducer 2 (Trop-2), modulators of cluster of differentiation 52 (CD52), modulators of B-cell maturation antigen (B-cell maturation antigen),antigen (BCMA) modulators, enzyme modulators, platelet-derived growth factor receptor A (PDGFRA) modulators, cluster of differentiation 319 (CD319 or SLAMF7) modulators, programmed cell death protein 1 and programmed death-ligand 1 (PD-1 / PD-L1) inhibitors / modulators, B lymphocyte antigen cluster of differentiation 19 (CD19) inhibitors, B lymphocyte antigen cluster of differentiation 20 (CD20) modulators, cluster of differentiation 3 (CD3) modulators, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors, T-cell immunoglobulin and mucin-domain containing 3 (T-cell immunoglobulin and mucin-domain modulators of T cell immunoreceptor with Ig and ITIM domain (TIGIT), modulators of V-domain Ig suppressor of T cell activation (VISTA), modulators of indoleamine 2,3-dioxygenase (IDO or INDO), modulators of poliovirus receptor-related immunoglobulin domain-containing protein (PVRIG), modulators of lymphocyte-activation gene 3 (L-activation gene 3), ... T cell immunoreceptor with Ig and ITIM domain (TIGIT), modulators of V-domain Ig suppressor of T cell activation (VISTA), modulators of indoleamine 2,3-dioxygenase (IDO or INDO), modulators of poliovirus receptor-related immunoglobcluster of differentiation 223 (CD223) antagonists, cluster of differentiation 276 (CD276 or B7-H3) antigen modulators, cluster of differentiation 47 (CD47) antagonists, cluster of differentiation 30 (CD30) modulators, cluster of differentiation 73 (CD73) modulators, cluster of differentiation 66 (CD66) modulators, cluster of differentiation w137 (CDw137) agonists, cluster of differentiation 158 (CD158) modulators, cluster of differentiation 27 (CD27) modulators, cluster of differentiation 58 (CD58) modulators, cluster of differentiation 80 (CD80) agonists, 80 (CD80) modulators, cluster of differentiation 33 (CD33) modulators, cluster of differentiation 159 (CD159 or NKG2) modulators, glucocorticoid-induced TNFR-related (GITR) protein modulators, killer Ig-like receptor (KIR) modulators, growth arrest-specific protein 6 (GAS6) / AXL pathway modulators, A proliferation-inducing ligand (APRIL) receptor modulators, human leukocyte antigen (HLA) modulators, epidermal growth factor receptor (EGFR) modulators,receptor (EGFR) modulators, B lymphocyte cell adhesion molecule modulators, cluster of differentiation w123 (CDw123) modulators, Erbb2 tyrosine kinase receptor modulators, endoglin modulators, mucin modulators, mesothelin modulators, hepatitis A virus cellular receptor 2 (HAVCR2) antagonists, cancer-testis antigen (CTA) modulators, tumor necrosis factor receptor superfamily member 4 (TNFRSF4 or 0X40) modulators, adenosine receptor modulators, inducible T cell co-stimulator (ICOS) modulators, cluster of differentiation 40 (CD40) modulators, tumor-infiltrating lymphocyte (TIL) therapy or T-cell receptor (T-cell These include, but are not limited to, drugs that exhibit mechanisms of action such as TCR (transducer receptor) therapy.

[0054] Exemplary drugs that may be included in the delivery devices described herein include etanercept, abatacept, adalimumab, evolocumab, exenatide, secukinumab, erenumab, galcanezumab, fremanezumab-vfrm, alirocumab, methotrexate (amethopterin), tocilizumab, interferon beta-1a, interferon beta-1b, peginterferon beta-1a, sumatriptan, darbepoetin alfa, belimumab, sarilumab, semaglutide, dupidem These include, but are not limited to, ramucirumab, reslizumab, omalizumab, glucagon, epinephrine, naloxone, insulin, amylin, vedolizumab, eculizumab, ravulizumab, crizanlizumab-tmca, certolizumab pegol, satralizumab, denosumab, romosozumab, benralizumab, emicizumab, tildrakizumab, ocrelizumab, ofatumumab, natalizumab, mepolizumab, risankizumab-rzaa, ixekizumab, and immune globulin.

[0055] Exemplary drugs that may be included in the delivery devices described herein also include, but are not limited to, ipilimumab, nivolumab, pembrolizumab, atezolizumab, durvalumab, avelumab, cemiplimab, rituximab, trastuzumab, ado-trastuzumab emtansine, fam-trastuzumab deruxtecanqui, pertuzumab, transtuzumab pertuzumab, alemtuzumab, belantamab mafodotin blmf, bevacizumab, bri Oncology treatments such as natumomab, brentuximab vedotin, cetuximab, daratumumab, elotuzumab, gemtuzumab ozogamicin, 90-yttrium-ibritumomab tiuxetan, isatuximab, mogamulizumab, moxetumomab pasudotox, obinutuzumab, ofatumumab, olaratumumab, panitumumab, polatuzumab vedotin, ramucirumab, sacituzumab govitecan, tafasitamab, or margetuximab.

[0056] Exemplary drugs that may be included in the delivery devices described herein include "generic" or biosimilar equivalents of any of the foregoing, and the foregoing molecular names should not be construed as being limited to each "originator" or "brand" version, such as, by way of non-limiting example, the originator drug adalimumab, and biosimilars such as adalimumab-afzb, adalimumab-atto, adalimumab-adbm, and adalimumab-adaz.

[0057] Exemplary drugs that may be included in the delivery devices described herein also include, but are not limited to, those used in post- or pre-operative chemotherapy, such as alkylating agents, plant alkaloids, antitumor antibiotics, antimetabolites, or topoisomerase inhibitors, enzymes, retinoids, or corticosteroids. Exemplary chemotherapy drugs include, by way of example only, 5-fluorouracil, cisplatin, carboplatin, oxaliplatin, doxorubicin, daunorubicin, idarubicin, epirubicin, paclitaxel, docetaxel, cyclophosphamide, ifosfamide, azacitidine, decitabine, bendamustine, bleomycin, bortezomib, busulfan, cabazitaxel, carmustine, cladribine, cytarabine, dacarbazine, etoposide, fludarabine, gemcitabine, irinotecan, leucovorin, melphalan, methotrexate, pemetrexed, mitomycin, mitoxantrone, temsirolimus, topotecan, valrubicin, vincristine, vinblastine, or vinorelbine.

[0058] Exemplary drugs that may be included in the delivery devices described herein also include, but are not limited to, analgesics (e.g., acetaminophen), antipyretics, corticosteroids (e.g., hydrocortisone, dexamethasone, or methylprednisolone), antihistamines (e.g., diphenhydramine or famotidine), antiemetics (e.g., ondansetron), antibiotics, antiseptics, anticoagulants, fibrinolytics (e.g., recombinant tissue plasminogen activator (r-TPA)), antithrombolytic agents, or diluents such as sterile water for injection (SWFI), 0.9% saline, 0.45% saline, 5% dextrose in water, 5% dextrose in 0.45% saline, lactated Ringer's solution, heparin lock flush solution, 100 U / mL heparin lock flush solution, or 5000 U / mL heparin lock flush solution.

[0059] Pharmaceutical formulations comprising any of the drugs described herein, for example, a pharmaceutical formulation comprising a drug listed herein (or a pharmaceutically acceptable salt thereof) and a pharmaceutically acceptable carrier, are also contemplated for use in the delivery devices described herein. Such formulations may contain one or more other active ingredients (e.g., in combination with one or more active drugs), or may be the only active ingredient, and may also include dispersion enhancers (e.g., animal-derived, human-derived, or recombinant hyaluronidase enzymes), concentration modifiers or enhancers, stabilizers, buffers, or other excipients, administered separately or co-formulated.

[0060] Exemplary drugs that may be included in the drug delivery devices described herein include AC, high-dose AC, TCH, GT, EC, TAC, TC, TCHP, CMF, FOLFOX, mFOLFOX6, mFOLFOX7, FOLFCIS, CapeOx, FLOT, DCF, FOLFIRI, FOLFIRINOX, FOLFOXIRI, IROX, CHOP, R-CHOP, RCHOP-21, Mini-CHOP, Maxi-CHOP, VR-CAP, high-dose CHOP, EPOCH, dose-adjusted EPOCH, R-EPOCH, CODOX-M, IVAC, HyperCVAD, R-HyperCVAD, SC-EPOCH-RR, DHAP, ESHAP, GDP, ICE, MINE, CEPP, CDOP, GemOx, CEOP, CEPP, CHOEP, CHP, GCVP, DHAX, CALGB These include, but are not limited to, multidrug treatment regimens such as 8811, HIDAC, MOpAD, 7+3, 5+2, 7+4, MEC, CVP, RBAC500, DHA-Cis, DHA-Ca, DHA-Ox, RCVP, RCEPP, RCEOP, CMV, DDMVAC, GemFLP, ITP, VIDE, VDC, VAI, VDC-IE, MAP, PCV, FCR, FR, PCR, HDMP, OFAR, EMA / CO, EMA / EP, EP / EMA, TP / TE, BEP, TIP, VIP, TPEx, ABVD, BEACOPP, AVD, Mini-BEAM, IGEV, C-MOPP, GCD, GEMOX, CAV, DT-PACE, VTD-PACE, DCEP, ATG, VAC, VelP, OFF, GTX, CAV, AD, MAID, AIM, VAC-IE, ADOC, or PE.

[0061] In general, all terms used in the claims should be interpreted according to their ordinary meaning in the art unless expressly specified otherwise herein. All references to elements, devices, members, components, means, etc. should be openly interpreted as referring to at least one instance of the element, device, member, component, means, etc. unless expressly specified otherwise. [Brief explanation of the drawings]

[0062] Embodiments of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0063] [Figure 1] 1 is a perspective view of a preferred embodiment of an inventive power unit of a medication delivery device. FIG. [Figure 2] FIG. 2 is a perspective view of the power unit of FIG. 1 as seen from another direction. [Figure 3] FIG. 2 is a view showing the power unit of FIG. 1 without the front cover and rear cover. [Figure 4] FIG. 4 is a view showing the power unit of FIG. 3, further excluding the chassis and front frame. [Figure 5] FIG. 5 shows the power unit of FIG. 4 further excluding the RFID antenna, interface elements, switch activator, vibrator, battery cell, rear cap, and screws. [Figure 6A] FIG. 6 shows the power unit of FIG. 5, with only the drive unit, pusher unit and encoder shown. [Figure 6B] FIG. 6B is a side view of the drive unit, the pusher unit, and the encoder shown in FIG. 6A. [Figure 7] 1 is a schematic diagram of a preferred embodiment of a drug delivery device. DETAILED DESCRIPTION OF THE INVENTION

[0064] The inventive concept will now be described in more detail with reference to the accompanying drawings, in which exemplary embodiments are shown. However, the inventive concept may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Elements, components, and portions of different examples, embodiments, or variations, but which have the same or similar functionality, are indicated by the same reference numerals in the figures.

[0065] 1-6B show possible embodiments of an inventive power unit 2 of a medication delivery device in perspective views from a distal outer perspective. The power unit 2 is adapted to be coupled to a drug unit 3, which is not shown in FIGS. 1-6B but is shown schematically in FIG. 7. To administer a drug to a patient, the drug unit 3 is adapted to be inserted into the patient's body together with a drug delivery element, and the power unit 2 is adapted to release the drug contained in the drug unit 3 through the drug delivery element. The power unit 2 as shown here is specifically adapted to administer a certain dose of the drug, i.e., only a portion of the drug contained in the drug unit 3 is administered.

[0066] The drug delivery device 1 comprises both a power unit 2 and a drug unit 3. As can be seen in Figure 7, the distal end of the power unit 2 coincides with the distal end 12 of the drug delivery device 1. The proximal end 11 of the drug delivery device 1 is formed by the drug unit 3. The main longitudinal axis 13 of the drug delivery device 1 extends from the distal end 12 to the proximal end 11 along the injection direction.

[0067] 1 and 2, the power unit 2 includes an outer housing 20 having a front cover 201 and a rear cover 202. A front frame 203 is attached to the proximal end of the front cover 201. The front frame 203 forms the proximal end of the power unit 2.

[0068] The proximal end of the power unit 2 is provided with an opening for receiving the medication unit 1. The opening is at least partially surrounded by an interface element 211, which serves to releasably attach the medication unit 1 to the power unit 2 by way of a bayonet connection.

[0069] Located within the housing 20 is a chassis 212 (Figure 3), which forms the main structural component of the power unit 2. The interface element 211 is attached to the chassis 212 by means of screws.

[0070] The power unit 2 comprises an electronic unit 22, which is best shown in Figures 4 and 5. The electronic unit 22 comprises a printed circuit board (PCB) 221 on which a controller 222 is arranged. The controller 222 is provided as an integrated circuit in the form of a microchip and serves to control the various functional components of the power unit 2, in particular the stepper motor 231. The electronic unit 22 further comprises an RFID antenna 223, which surrounds the interface element 211 and is connected to the controller 222. Two rechargeable battery cells 224 are provided in the distal region of the power unit 2 to supply electrical energy to the electronic unit 22, the stepper motor 231 and the encoder 25.

[0071] Also arranged within the housing 20 of the power unit 2 is a vibrator 213 which serves to provide a tactile signal to the user. Further signalling elements, in particular LEDs, are provided to provide the user with visual and / or audible information regarding the status of the device.

[0072] A retaining plate 214 serves to hold the various electronic components and connect them to the PCB 221 and, among other things, to the controller 222 .

[0073] The drive unit 23 of the power unit 2 is particularly well shown in Figures 6A and 6B. The drive unit 23 serves to proximally displace the rod-shaped pusher element 241 of the pusher unit 24 in order to expel the medicament from the medicament container of the medicament unit 3. For this purpose, the drive unit 23 comprises a stepper motor 231 having an outer stator 232 and an inner rotor 233. A hollow motor shaft is fixedly attached to the rotor 233, but is not visible in the figures. The stepper motor 231 is connected to the controller 222 by way of leads 235 in order to be controlled and supplied with electrical energy.

[0074] A drive nut 234 is fixedly attached to the hollow motor shaft and therefore rotates with the rotor 233 without an intermediately coupled gear unit. The drive nut 234 serves to translate the rotational motion of the rotor 233 into proximal (or distal) displacement of the pusher element 241. To this end, the drive nut 234 includes an internal thread that is engaged by an external thread of the pusher element 241. Due to the mutual threaded engagement, the rotation of the drive nut 234, and therefore the rotation of the rotor 233, is directly coupled to the longitudinal displacement of the pusher element 241.

[0075] The pusher element 241 is part of the pusher unit 24, which further comprises a front adapter 242 and an anti-rotation element 243. The front adapter 242 forms the proximal end of the pusher element 241 and is adapted to contact and engage the plunger of the medication unit 3. The anti-rotation element 243 is attached to the distal end of the pusher element 241 in a torque-resistant manner and prevents the pusher element 241 from being rotated together with and by the drive nut 234. For this purpose, the anti-rotation element 243 is guided by a longitudinally extending guide groove provided on the inner surface of the chassis 212.

[0076] Thus, the pusher element 241 extends along the main longitudinal axis 13 through the drive nut 234 and through the hollow motor shaft attached to the rotor 233 .

[0077] The encoder disk 251 of the encoder 25 is fixedly attached to or integral with the drive nut 234. The circular encoder disk 251 has a number of through-openings spaced at regular intervals around the circumference of the disk. The through-openings serve to detect the rotational state of the encoder disk 251, and thus of the drive nut 23, by means of an optical sensor in the form of a photointerrupter 252 (see FIGS. 6A and 6B). The number of through-openings in the encoder disk 251 is preferably equal to or an integer multiple of the number of steps required by the stepper motor 231 for one complete rotation of the rotor 233. The stepper motor 231 may be, for example, a 7.5° stepper motor with a full step length of 12.7 μm. The photointerrupter 252 is connected to the controller 222, where the signal generated by the photointerrupter 252 is further processed and used to control the stepper motor 231.

[0078] In order to monitor the back EMF of the stepper motor 231, a respective back EMF monitoring device is preferably provided on the PCB 221. The back EMF monitoring device essentially serves to measure the electrical energy flowing into and out of the stepper motor 231. One particularly suitable device for monitoring back EMF is the commercially available product StallGuard2™ from TRINAMIC Motion Control GmbH & Co. KG, Hamburg, Germany.

[0079] A switch activator 261 is provided to detect coupling of the power unit 2 with the medication unit 3. The switch activator 261, only its distal portion of which is visible in Figure 4, extends into a proximal opening of the power unit 2 that serves to receive the medication unit 3. Upon insertion of the medication unit 3 into the proximal opening, the switch activator 261 is displaced distally by the medication unit 3 against the biasing force of an actuation spring 262 to activate a switch, not shown. The switch is connected to the controller 222, which is thus notified by the coupling of the medication unit 3.

[0080] FIG. 7 shows a schematic diagram of a medication delivery device 1 of the present invention having a power unit 2 designed, for example, according to the embodiment of FIGS. 1 to 6B . The medication unit 2 is coupled to the power unit 2. The medication unit 2 comprises an outer housing 30 surrounding a medication container 31 serving to store the medication to be injected. The medication is expelled from the medication container 31 through a needle 33 by proximally displacing a pusher element 241 of the power unit 2 until a front adapter 242 contacts and proximally pushes a plunger 32 disposed in the medication container 31. Before and after an injection, the needle 33 is externally covered by a needle cover 34. An injection is initiated by placing the medication delivery device 1 at the injection site. In doing so, the needle cover 34 is displaced distally, i.e., retracted, against the biasing force of a spring, thus initiating the injection. The retraction of the needle cover 34 is indicated to the controller 222 via a corresponding mechanism, which then activates the stepper motor 231 to perform the injection. A closure cap 35 serves to seal the needle 33 before use of the medication unit 3 .

[0081] In the following, the use of the drug delivery device 1 will be described with reference to FIG. 7, under the assumption that the power unit 2 of the device of FIG. 7 is designed according to the embodiment of FIGS. 1 to 6B.

[0082] Between injections, power unit 2 is in sleep mode. A crystal in the RTC clock on PCB 221 is kept running by a button cell battery to prevent the power unit 2 from losing track of time. The RTC clock is calibrated by connecting power unit 2 to, for example, the patient's smartphone or other intermediary device, either wirelessly or via a network-connected electrical connector 225 that transmits information. The electrical connector 225 serves to recharge the battery cell 224 and / or for data connection.

[0083] Connection to a smartphone or other smart device can be achieved, for example, by a Bluetooth Low Energy (BLE) module. Data such as time of injection, dose, expiration date, amount of medication in medication container 31, medication type, amount of medication injected, and / or injection rate preference are transmitted before and / or after a successful or unsuccessful injection attempt.

[0084] When the user turns on or resets power unit 2, a home-going sequence is initiated in which controller 222 displaces pusher element 241 distally until it hits and activates an end limit switch inside power unit 2. Controller 222 then displaces pusher element 241 proximally until it reaches the "home position" HP as shown in FIG.

[0085] Once the medication unit 3 is attached to the power unit 2 using a bayonet movement, the power unit 2 is activated by means of the switch activator 26, i.e. the system is woken up. Using the RFID antenna 223, the information on the RFID tag of the medication unit 3 is read. If all the information is correct, the user is prompted, for example by a green light on the progress bar on the power unit 2 and tactile feedback from the vibrator 213 and / or a sound from a buzzer.

[0086] If the information received from the RFID tag of the medication unit 3 is deemed incorrect, such as it being too early for injection or the medication has expired, then for example an orange light and / or tactile feedback is presented to the user by the power unit 2.

[0087] If the battery 224 is low and there is no power remaining to complete the injection, the user is prompted, for example, via a battery indicator LED on the power unit 2. The battery status can also be transmitted wirelessly, for example, a smartphone app prompting the user if the power unit 2 suspects it has run out of battery power. The battery status is preferably indicated by a progress bar when the user charges the power unit 2 or picks it up after it has been stationary for a predetermined time limit. The power unit 2 is then preferably activated by an accelerometer (G-sensor) located on the power unit 2 that is activated when the patient lifts the device.

[0088] If the information received from the RFID tag is deemed correct, i.e., if a corresponding injection is possible, the controller 222 initiates an initial calibration and positioning procedure before prompting the user with a green light. The first step of this calibration and positioning procedure involves setting thresholds for motor control based on back EMF sensing. The thresholds relate, for example, to detecting contact between the pusher element 241 and the plunger 32 and detecting stalling of the stepper motor 231. For this purpose, the thresholds (or reference values) are adjusted depending on the amount of current supplied to the stepper motor 231 to displace the pusher element 241, the rotation frequency of the rotor 233, and / or the displacement speed of the pusher element 241. The calibration procedure preferably also takes into account possible compensation for unknown effects such as motor coil temperature. Calibration can be achieved, for example, by performing test displacements of the pusher element 241 without contacting the plunger 32 and considering the electrical energy supplied to the stepper motor 231 and the corresponding measured back EMF. Additionally or alternatively, reference values ​​received from the medication unit's RFID tag may also be applied.

[0089] In the second step of the calibration and positioning procedure, the pusher element 241 is displaced proximally by the controller until it contacts the plunger 32 at plunger position PP (FIG. 7), which is detected by comparing the measured back EMF with a preset threshold. In doing so, the encoder 25 is used to detect possible step losses of the stepper motor 231. Such step losses due to stalling may occur, in particular, when the pusher element 241 strikes the plunger 32 at the plunger adapter 242, displacing the plunger 32 proximally a short distance from plunger position PP to the dose dispense start position DSP until the stepper motor 231 stops.

[0090] If the patient receives a green light after attaching the medication unit 3 to the power unit 2, the patient can proceed by removing the closure cap 35, which has been unlocked by the bayonet attachment of the medication unit 3 to the power unit 2. Once the closure cap 35 is removed, the needle cover 34 is exposed to the patient, which allows the needle cover 34 to be retracted.

[0091] The removal of the closure cap 35 is preferably detected by the controller 222 by suitable means. When the removal of the closure cap 35 is detected, the controller 222 preferably initiates a pre-delay phase, during which the stepper motor 231 remains idle to allow the pressure inside the drug container 31 and the fluid path to equalize. Due to the short proximal displacement of the plunger 32 from the plunger position PP to the dose dosing start position DSP, which is unavoidable in practice, a pressure increase may occur in particular. The pre-delay phase allows a particularly accurate dose dosing to be achieved. When the pre-delay phase is over and the device is ready for injection, the user can be notified by means of a visual, audible and / or tactile signal.

[0092] To initiate an injection, the patient presses the device with the needle cover 34 against the injection site. In doing so, the needle cover 34 is retracted into the housing 20 of the power unit 2 until the needle 33 approaches the final injection depth. Retraction of the needle cover 34 activates a mechanical start switch inside the medication unit 3, which is registered by the controller 222. The controller 222 then activates the injection sequence of the stepper motor 231. During the injection sequence, the drive nut 234 is rotated by the stepper motor 231. Because the anti-rotation element 243 prevents the rod-shaped pusher element 241 from rotating, the rotation of the drive nut 234 translates into axial displacement of the pusher element 241 from the dose dosing start position DSP toward the dose dosing end position DEP. During the displacement, the stepper motor 231 is controlled by monitoring the back EMF generated by the stepper motor 231. When a predetermined threshold, close to motor stall, is reached, the motor speed is reduced by the controller 222 to reduce the force required for injection. If the threshold is nevertheless met or exceeded, the stepper motor 231 is reversed by the controller 222 and the injection is aborted. Thus, by monitoring the back EMF, stalling is effectively prevented. The exact position of the pusher element 241 at the time of stop is known due to measurement by the encoder 25. The stroke required for the complete injection of the dose is known based on information received from the medication unit 3 by the RFID antenna 223 and compared with the actual movement of the drive nut 234 measured by the encoder 25. When the encoder 25 detects that the pusher element 241 has reached a dose end position DEP, the full dose has been injected and the displacement of the pusher element 241 is stopped by the stepper motor 231.

[0093] Once the injection is complete, the controller 222 activates a post-delay phase during which the stepper motor 231 again remains idle to allow the pressure inside the medication container 31 and the fluid path to equalize after the injection. The post-delay phase makes it possible to achieve particularly accurate volume dosing for any further dose injections. When the post-delay phase is over and the device is ready to be removed from the injection site, the user can be notified by means of a visual, audio and / or tactile signal.

[0094] Once the post-delay phase is over, the controller 222 causes the stepper motor to return the pusher element 241 to the "home position" HP as quickly as possible.

[0095] When the user lifts the device from the injection site, a mechanical start switch in the medication unit 3 is deactivated and the controller 222 stops the stepper motor 231. To continue the injection, the patient simply presses the needle cover 34 against the injection site again, and the start switch is again activated and the injection is continued by the controller 222. However, if the user lifts the device further, the needle cover 34 rotates about the main longitudinal axis 13 due to corresponding guide paths inside the medication unit 3, which moves the needle cover 34 to a locked-out position, which prevents the needle cover from being retracted into the housing 30 again. Thus, further injections are prevented and the needle 33 is covered by the needle cover 34 to protect it from harming the patient.

[0096] To remove medication unit 3 from power unit 2, the user rotates medication unit 3 90 degrees in the opposite direction to that used during the attachment procedure. The disconnection of the bayonet coupling is registered by the controller via switch activator 261. As a result, power unit 2 begins transmitting injection information via controller 222 to the patient's smartphone or another device via wireless means or via electrical connector 225, and then returns to sleep mode.

[0097] Additionally, an auxiliary sensor can be used to facilitate detection of the plunger position, for example a mouse sensor, for example an optical navigator.

[0098] The inventive concept has been primarily explained with reference to some examples.

[0099] However, as will be readily apparent to those skilled in the art, other embodiments than those disclosed above are equally possible within the scope of the inventive concept as defined by the appended claims. In particular, it should be noted that the combinations of elements, components, and parts shown in the figures should be understood as merely non-limiting examples. Individual elements, components, and parts of the various embodiments described and / or shown in the figures can essentially be interchanged with one another as desired, and can be supplemented, for example, with additional elements. Various modifications to the described embodiments are possible and will occur to those skilled in the art without departing from the invention as defined by the following claims.

Claims

1. A power unit (2) for a drug delivery device (1) for delivering a drug from a drug container (31) to a human or animal patient, comprising: a pusher element (241) adapted to engage and push the plunger (32) proximally to expel the medicament from the medication delivery device (1); a drive unit (23) comprising a drive nut (234) and a stepper motor (231) having a rotor (233) and a stator (232), the drive nut (234) adapted to translate rotational movement of the rotor (233) into proximal displacement of the pusher element (241); a controller (222) for controlling the stepping motor (231); an encoder (25) for determining the displacement position of the pusher element (241); the drive unit (23) is configured as a direct drive such that the drive nut (234) rotates at the same speed as the rotor (233) of the stepping motor (231) and the rotational movement of the drive nut (234) is directly converted into a displacement of the pusher element (241); The power unit (2), wherein the controller (222) is configured to monitor the back electromotive force of the stepping motor (231).

2. 2. The power unit (2) of claim 1, wherein the controller (222) is configured to detect contact between the plunger (32) and the pusher element (241) based on the monitoring of the back electromotive force.

3. 3. A power unit (2) according to claim 1 or 2, wherein the controller (222) is configured to relate the monitored back EMF to the current supplied to the stepper motor (231).

4. 4. The power unit (2) of claim 1, wherein the controller (222) is configured to correlate the monitored back electromotive force with a displacement position of the pusher element (241) as determined by the encoder (25).

5. 5. The power unit (2) according to claim 1, wherein the encoder (25) measures the rotational position of the drive nut (234) and / or the displacement position of the pusher element (241) to determine the displacement position of the pusher element (241).

6. Power unit (2) according to any one of claims 1 to 5, wherein the encoder (25) comprises an optical sensor, in particular a photoelectric sensor (252).

7. A power unit (2) according to any one of the preceding claims, wherein the encoder (25) comprises a disc (251) attached to or made integral with the drive nut (234).

8. 8. The power unit (2) according to any one of claims 1 to 7, wherein the controller (222) is configured to stop the stepper motor (231) when a predetermined displacement position of the pusher element (241) as determined by the encoder (25) is reached.

9. The power unit (2) of any one of claims 1 to 8, wherein the controller (222) is configured to receive a volumetric dosing instruction, preferably from a drug unit (3) of the drug delivery device (1) or from a user, and to control the stepper motor (231) to move the pusher element (241) to a displacement position corresponding to the received volumetric dosing instruction and / or to displace the pusher element (241) proximally by a displacement distance corresponding to the received volumetric dosing instruction.

10. 10. A power unit (2) according to claim 9, additionally comprising an RFID (radio frequency identification) unit (223) and / or a wireless receiving unit for receiving said volumetric dosage instructions.

11. The power unit (2) of any one of claims 1 to 10, wherein the controller (222) is configured to detect removal of a closure cap (35) of a drug unit (3) of the drug delivery device (1) and, upon detecting removal of the closure cap (35), enter a pre-delay phase during which the stepper motor (231) remains idle.

12. 12. The power unit (2) of any one of claims 1 to 11, wherein the controller (222) is configured to enter a post-delay phase upon completion of the proximal displacement of the pusher element (241), during which the stepper motor (231) remains idle.

13. A power unit (2) as described in any one of claims 1 to 12, wherein the power unit (2) is adapted to receive a drug unit (3) of the drug delivery device (1) by means of releasable attachment, the drug unit (3) comprising a drug container (31) for storing the drug and a drug delivery element (33) having a proximal end through which the drug can be delivered to the patient.

14. A medication unit (3) adapted to be received by the power unit (2) comprising an RFID unit (223) according to claim 10, and comprising an RFID tag for storing volumetric dosing instructions that can be read by the RFID unit (223) of the power unit (2).

15. A drug delivery device (1) comprising a power unit (2) according to any one of claims 1 to 13 and a drug unit (3).

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