Apparatus and method for detecting a user fill volume in a medication delivery device - Patents.com

Abstract

The drug delivery device includes an infusion pump system having a reservoir, a fluid path connected between the reservoir and an insertion mechanism, a plunger disposed inside the reservoir, and a pump drive mechanism coupled to the reservoir. The drug delivery device further includes a processing device configured to determine a user fill volume of the fluid drug by analyzing a location of the plunger inside the reservoir when filling of the fluid drug is completed. The processing device is configured to determine a user fill volume of the fluid drug by sensing a pressure inside the reservoir.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to medical devices, and more particularly to medication delivery devices having an infusion pump system for detecting a user fill volume of a fluid medication. [Background technology]

[0002] Infusion pumps usually have a reservoir with a known volume of fluid medication and a known dosing stroke volume for counting down the dose to estimate how much fluid is filled into the reservoir by the user. Without knowing the exact volume of fluid in the reservoir, the user cannot know how much medication is filled into the reservoir each time. Therefore, the user must always measure the amount of medication each time when filling the reservoir, which is a burden.

[0003] Typical methods for determining the user fill volume inside the reservoir are expensive and sometimes burdensome. For example, some infusion pumps have a separate fill device that measures the exact fill and wirelessly communicates that fill volume to the main pump or controller. Other infusion pumps do not measure the input fill but have a method for counting down from a specific point (e.g., some devices count down from 60U remaining).

[0004] For medical devices such as wearable drug delivery pumps where some or all of the components are disposable for ease of use and cost effectiveness, the addition of another component to measure the user fill volume and the associated increased cost and complexity to the medical delivery device is undesirable. Thus, there is a need to accurately detect a user fill volume in a reservoir of a medical delivery device having an infusion pump system without adding a new component and thereby increasing the complexity and cost of the infusion pump. Summary of the Invention

[0005] Exemplary embodiments of the present disclosure may address the above problems and / or shortcomings, as well as others not described above, and exemplary embodiments are not required to overcome the above-described shortcomings, and may not overcome the above-described problems.

[0006] The matters illustrated in this description are provided to assist in a comprehensive understanding of the exemplary embodiments of the present disclosure. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the spirit and scope of the present disclosure. In addition, descriptions of well-known functions and structures are omitted for clarity and conciseness.

[0007] According to an exemplary aspect of the present disclosure, a medication delivery device includes an infusion pump system having a reservoir, an insertion mechanism, a flow path between the reservoir and the insertion mechanism, a plunger inside the reservoir, and a pump drive mechanism coupled to the reservoir, and further includes a processing device configured to determine a user fill volume of the fluid medication by analyzing a location of the plunger relative to the reservoir when filling of the fluid medication is completed.

[0008] According to a further exemplary aspect of the present disclosure, the processing device is configured to determine the location of the plunger by sensing a pressure inside the reservoir. The infusion pump system further includes a pressure sensor that senses the pressure inside the reservoir.

[0009] According to a further exemplary aspect of the present disclosure, the flow path is selectively blocked when loading of the fluid medication is complete.

[0010] According to a further exemplary aspect of the present disclosure, the processing device determines an initial position of the pump drive mechanism.

[0011] According to a further exemplary aspect of the present disclosure, the processing device activates a pump drive mechanism that moves a plunger relative to the reservoir, and the processing device measures the movement of the pump drive mechanism from an initial position to when filling of the fluid drug is completed.

[0012] According to a further aspect of the present disclosure, the current position of the pump drive mechanism is determined when the pressure inside the reservoir exceeds a threshold pressure.

[0013] According to a further exemplary aspect of the present disclosure, the processing device is configured to determine the user fill volume by calculating a difference between an initial position and a current position of the pump drive mechanism.

[0014] According to a further exemplary aspect of the present disclosure, the processing device is configured to determine a position of the plunger by sensing a current in the pump drive mechanism, a force applied to the pump drive mechanism, and a torque applied to a motor of the pump drive mechanism.

[0015] According to a further exemplary aspect of the present disclosure, the processing device is configured to determine the location of the plunger by sensing a flow of the fluid medicament in the flow path. Further, the medicament delivery device can include a flow sensor to sense the flow of the fluid medicament in the flow path.

[0016] According to a further exemplary aspect of the present disclosure, the infusion pump system further includes a pusher connected to the pump drive mechanism and selectively coupled to the plunger inside the reservoir. Additionally, in an exemplary implementation, the plunger can be decoupled from the pump drive mechanism while the fluid medication is being loaded into the reservoir, thereby allowing the plunger to move or to move freely. [Brief description of the drawings]

[0017] The above and / or other exemplary aspects and advantages of the present disclosure will become apparent and will be more readily understood from the following description of exemplary embodiments taken in conjunction with the accompanying figures.

[0018] [Figure 1] FIG. 1 is a perspective view of a wearable fluidic medication delivery device constructed in accordance with an exemplary embodiment of the present disclosure. [Figure 2A] 2 is a plan bottom view of the fluidic drug delivery device of FIG. 1 constructed in accordance with an exemplary embodiment of the present disclosure. [Figure 2B] 2 is a top perspective view of the fluidic medication delivery device of FIG. 1 with the cover removed, constructed in accordance with an exemplary embodiment of the present disclosure. [Figure 3A] 2 is a partial side view illustrating a pressure sensor disposed within the fluid drug delivery device of FIG. 1 according to an exemplary implementation. [Figure 3B] FIG. 3B is a detailed view of a pressure sensor disposed within the fluid drug delivery device of FIG. 3A. [Figure 3C] FIG. 3B is a diagram showing details of an example of the pressure sensor of FIG. 3A. [Figure 4] FIG. 1 is a block diagram of exemplary components of a fluid drug delivery device constructed in accordance with an exemplary embodiment of the present disclosure. [Figure 5A] 1A-1C are top perspective views of a fluidic drug delivery device with the cover removed, constructed in accordance with an exemplary embodiment and shown at one stage of filling the reservoir. [Figure 5B] 1A-1C are top perspective views of a fluidic drug delivery device with the cover removed, constructed in accordance with an exemplary embodiment and shown at different stages of filling the reservoir. [Figure 5C] 1A-1C are top perspective views of a fluidic drug delivery device with the cover removed, constructed in accordance with an exemplary embodiment and shown at different stages of filling the reservoir. [Figure 5D] FIG. 5B is a side perspective view of the fluidic drug delivery device of FIG. 5A. [Figure 6] 11 is a flowchart of an illustrative operation of an exemplary fluid medication delivery device executing a user fill volume detection algorithm, in accordance with an illustrative embodiment of the present disclosure. [Figure 7] 1A-1C show example internal reservoir pressure data measurements from a fluidic drug delivery device according to an exemplary embodiment of the present disclosure. [Figure 8] 1 depicts a user fill volume detection system and methodology, according to an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Throughout the figures, like reference numbers will be understood to denote like elements, features, and structures.

[0020] Referring now to the figures, in which like reference numerals refer to the same or corresponding parts throughout the several views, embodiments of the present disclosure are described as follows.

[0021] It will be understood that the terms "comprises," "including," "comprises," and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0022] It will be further understood that, although the terms "first," "second," "third," etc. may be used herein to describe various elements, components, regions, layers, and / or sections, these elements, components, regions, layers, and / or sections are not limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section.

[0023] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Phrases such as "at least one" when preceding a list of elements modify the entire list of elements and not each individual element of the list. Additionally, terms such as "unit"-er(-or) and "module" described herein refer to an element for performing at least one function or operation, and may be implemented in hardware, software, or a combination of hardware and software.

[0024] Various terms are used to refer to particular system components, and different companies may refer to their components by different names, and this document does not intend to distinguish between components that differ in name but not function.

[0025] Matters of these exemplary embodiments that are clear to those skilled in the art to which these exemplary embodiments pertain may not be described in detail herein. In addition, various features of the exemplary embodiments may be implemented individually or in any combination or combinations as would be understood by one skilled in the art of pharmaceutical delivery devices.

[0026] The exemplary embodiment of the user fill volume detection algorithm described below is useful for utilizing one of the occlusion detection systems with an infusion pump system. An infusion pump system is generally understood to be a type of pump that works on the principle of filling a chamber (e.g., with liquid drug from a reservoir) in one stage and emptying the fluid from the chamber (e.g., toward a delivery device such as a cannula deployed inside the patient's body) in another stage. In the exemplary embodiment of the present disclosure, the user fill volume detection system described below further uses several technical principles such as (a) a fluid detection method for measuring the pressure inside the reservoir chamber, (b) a plunger decoupled from the pump drive mechanism, (c) a pump drive mechanism that starts in a known state (known position), and (d) a flow path that can be selectively blocked during initialization (e.g., by a downstream vent).

[0027] For illustrative purposes, reference is made to an exemplary implementation of a drug delivery device 10 having a reciprocating plunger pump type, as shown in the exemplary embodiment of Figures 1, 2A, 2B, and 3A-3C. Figure 1 is a perspective view of the wearable drug delivery device 10 including a base plate 12, a cover 14, and an insertion mechanism 16. The insertion mechanism 16 is configured to insert a cannula into the skin of a patient to deliver a fluid drug.

[0028] 2A is a plan view of the exterior of the base plate 12 in the drug delivery device 10. In the exemplary implementation shown in FIG. 2A, the drug delivery device 10 further includes a fill tab 18 having an underflow air membrane 20 for providing pressure equalization and also a sterile environment, and a fill port 22 for receiving the needle of a filled syringe 24. As shown in FIG. 2B, the drug delivery device 10 includes a reservoir 26 connected to the fill port 22 via an inlet channel, thereby allowing a user to fill the reservoir 26 with a fluid drug by inserting the needle of the filled syringe 24 into the fill port 22. It should be understood that different mechanisms and methods can be used to fill the drug delivery device 10 with a fluid drug.

[0029] FIG. 2B is a perspective view of the drug delivery device 10 of FIG. 1 with the cover 14 removed. The base plate 12 supports the insertion mechanism 16, the motor 28, a power source such as a battery 30, a printed circuit board (PCB) 32 having a microcontroller 31, a memory 33, and other electronic components, and a reservoir 26 for storing a fluid drug to be delivered through the insertion mechanism 16 to a patient (or user) through an outlet flow path 34 from an outlet port of the reservoir 26. In an exemplary implementation, the reservoir 26 has an inlet port connected to the fill port 22 through an inlet flow path for receiving the fluid drug. As shown in FIG. 2B, the reservoir 26 includes a plunger 36 having a stopper assembly. The proximal end 25 of the reservoir 26 is also provided with a plunger driver assembly 38 having a gear anchor 40, a telescoping screw system (not shown), and a nut 41 rotated through a gear train 42 operably connected to the motor 28, in an exemplary implementation. 2B, a gear anchor 40 disposed within the proximal end 25 of the reservoir 26 is rotationally connected to a nut 41, which is engaged with a gear train 42 operated by the motor 28. In addition, the gear anchor 40 is rigidly attached to the base plate 12 and is responsive to forces from the movement of the plunger and fluid pressure.

[0030] Referring to the example of Fig. 2B, the drug delivery device 10 further includes a pusher 44 disposed inside the reservoir 26 and positioned between the plunger 36 and the gear anchor 40. In an exemplary implementation, the pusher 44 can be fixedly connected, for example, to a telescoping screw system of the plunger driver assembly 38, such that the pusher 44 is moved axially to push the plunger 36 when the fluid drug inside the reservoir 26 is expelled. As shown in Fig. 2B, which illustrates an example of the device 10 in a starting position (before filling), the gear anchor 40 has a front surface that can abut the pusher 44 when the plunger driver assembly 38 is fully retracted, although the gear anchor 40 is not required to abut the pusher 44 depending on the dimensions of the reservoir 26 and the plunger driver assembly 38. In an exemplary implementation, the gear anchor 40 can include at least one opening or through hole (not shown) for venting, and the pusher 44 can have openings and / or gaps to allow for venting as it moves axially within the reservoir 26.

[0031] FIG. 3A illustrates an exemplary implementation of a pressure sensor 50 disposed in the reservoir 26 as a component for detection of a fluid medicament according to an exemplary embodiment of the present disclosure. FIG. 3B illustrates the pressure sensor 50 mounted relative to (e.g., in a wall of) the distal end 27 of the reservoir 26. FIG. 3C illustrates the pressure sensor 50 configured to measure pressure inside a chamber portion 48 defined in the reservoir 26 during operation of the medicament delivery device 10. In another exemplary implementation, the pressure sensor 50 can be disposed in other areas where the pressure of the chamber portion 48 can be measured. Furthermore, the pressure sensor 50 can be configured to communicate with the microcontroller 31 of the PCB 32 via a wired interface or wirelessly such that the pressure measured by the sensor 50 can be used to determine a user fill volume of the fluid medicament in the reservoir 26.

[0032] FIG. 4 is a system diagram 100 illustrating an exemplary implementation of components within an exemplary drug delivery device 10 having the infusion pump system of FIGS. 1, 2A, 2B, and 3A-3C for detecting a user fill volume of a fluid drug. Referring to the example of FIG. 4, the drug delivery device 10 can include a power storage subsystem 102, a fluidics subsystem 104, and an electronics subsystem 106 for controlling the operation of components within the fluidics subsystem 104, such as an insertion mechanism 16 for deploying a cannula for insertion into an injection site on a patient's skin. The power storage subsystem 102 includes a power source, such as one or more batteries 30, for providing power to the components within the electronics subsystem and the fluidics subsystems 104 and 106. The fluidics subsystem 104 includes a pump drive mechanism 37 including a motor 28, a gear train 42, a plunger drive assembly 38 for controlling a pusher 44 that selectively includes a plunger 36, and an outlet flow path 34. Further, for example, the fluidics subsystem 104 includes a fill port 22 for filling the reservoir 26 with a fluid agent.

[0033] Additionally, the electronics subsystem 106 includes a microcontroller 31 with an integrated or separate memory device 33 for controlling the infusion pump system to detect a user fill volume of the fluid medication filled in the reservoir 26. A user fill volume detection algorithm (see FIG. 6) according to an illustrative embodiment can be provided in the microcontroller 31 to measure the location of a plunger driven by a pump drive mechanism 37 and determine the amount of fluid medication inside the reservoir 26 that is filled by the patient (or user).

[0034] 5A, 5B, and 5C show an exemplary method for determining a user-fill volume of a fluid medicament filled in the reservoir 26 of the exemplary drug delivery device 10 described in FIGS. 1 to 3A. FIG. 5A shows an initial state of the reservoir prior to filling the fluid medicament in the drug delivery device 10, whereby the reservoir 26 is empty of fluid medicament and the plunger 36 is positioned at its most distal position inside the reservoir 26. A user (or patient) can insert the needle of a filled syringe 24 into a fill port 22 (see FIG. 2) provided in the base plate 12 having an inlet flow path from the fill port 22 to the reservoir 26. As the fluid medicament is transferred from the syringe 24 to the reservoir 26 via the inlet flow path, the volume of a fluid chamber portion 48 defined in the reservoir 26 by the front (fluid-facing) side 35 of the plunger 36 increases (see FIG. 5B). The plunger 36 has a stopper assembly formed of an elastic material to prevent any leakage of the fluid drug held within the fluid chamber portion 48 of the reservoir 26, thereby configuring the plunger 36 to seal off the fluid drug from entering the portion of the reservoir 26 defined by the rear side 39 of the plunger 26.

[0035] As shown in FIG. 5B, after the fluid drug filling is completed, the microcontroller 31 executes an initialization process to determine the volume of the fluid drug filled in the reservoir 26. When the fluid drug is filled in the reservoir 26, the plunger 36 moves freely to a first location between the proximal end 25 and the distal end 27 of the reservoir 26. After the fluid drug is filled, the flow path is blocked to prevent any fluid drug from flowing in the infusion pump system. Referring to the example of FIG. 5B, when the fluid drug filling is completed and the flow path is sealed, the pump drive mechanism starts to drive the pusher 44 inside the reservoir 26 from a known position of the pump drive mechanism defined in the initial position (Xo) of the pump drive mechanism, and the microcontroller 31 keeps track of how far the pusher 44 connected to the pump drive mechanism 37 has advanced from its initial position (Xo), for example, by reading a drive encoder 46 (see FIG. 5D) disposed inside the cover 14 of the drug delivery device 10. As shown in FIG. 5D, in an exemplary implementation, a drive encoder 46 can be connected to the gear train unit 42 and can provide feedback to the microcontroller 31 by sensing pump motor action and also rotation of the drive nut 41.

[0036] As shown in FIG. 5C, the pump drive mechanism continues to drive the plunger 36 in contact with, e.g., coupled to, the pusher 44 until pressure is generated in the flow path containing the reservoir as the plunger 36 is urged by the pusher 44 toward the distal end 27 of the reservoir 26. As explained above, the pressure in the flow path containing the reservoir 26 is sensed by a pressure sensor 50 (see FIG. 3A ) in accordance with an exemplary embodiment of the present disclosure. The pressure detected by the pressure sensor 50 is then adjusted to a predetermined threshold pressure (P ) according to, for example, the exemplary algorithm of FIG. thresh When the fluid path containing the reservoir 26 is pressurized, i.e., when the detected pressure exceeds a predetermined threshold pressure (P), as explained above, the plunger 36 is stopped at a second location within the reservoir 26 and the microcontroller 31 measures the forward movement of a pump drive mechanism coupled to the plunger 36 at the second location of the plunger 36, which the microcontroller 31 determines as the current position (Xn) of the pump drive mechanism 37.thresh ), it is understood that all drive train components in the pump drive mechanism 37 are fully engaged with the plunger 36 so that the fluid medicament inside the reservoir 26 can be pushed out for delivery. At this stage, the microcontroller 31 can determine the user fill volume of the reservoir 26 by calculating the difference between the initial position (Xo) and the current position (Xn) of the pump drive mechanism 37. Thus, by taking into account the difference between the initial position (Xo) and the current position (Xn), the volume available for dispensing can be calculated, which corresponds to the amount of fluid medicament filled by the patient (or user).

[0037] 6 is a flow chart diagrammatically illustrating an example of an operation 200 of the drug delivery device 10 performing user fill volume detection according to an exemplary implementation of an embodiment of the present disclosure, which may be implemented using a microcontroller 31 or other processing device for controlling or monitoring the pump operation of the drug delivery device 10. When a user (or patient) fills a fluid drug into the device, the downstream flow path is filled up to the vent first, evacuating all air in the downstream flow path before the plunger starts to move. A large portion of the volume filled by the user (e.g., the volume of the fluid chamber portion 48 shown in FIG. 5B) moves the plunger 36 from the distal end 27, or front, of the reservoir 26 to an unknown location between the distal end 27 (e.g., corresponding to a 0 U fill) and a known starting position (e.g., corresponding to a 310 U fill). For example, referring to FIG. 5B, the initialization process of operation 200 begins with the outlet flow path 34 blocked to liquid flow (e.g., by an optional downstream gas membrane 20), the reservoir plunger 36 disposed in an unknown location, and the pusher 44 connected to the pump drive mechanism 37 starting at a known position (Xo).

[0038] 6, after the user confirms that filling is complete, the microcontroller 31 reads the pressure and assigns this pressure to P0 (box 202). Then, in an exemplary implementation, the pump drive mechanism 37 starts driving the pusher 44, which is connected to the pump drive mechanism 37, to move one step increment toward the distal end 27 of the reservoir 26 to absorb the drive train compliance in the drug delivery device 10, and the microcontroller 31 reads the pressure and assigns this pressure to P1 (box 204) and checks whether one step increment is completed (block 206). If one step increment is not completed and pressure is generated and sensed, the microcontroller 31 analyzes the pressure (P0) to determine whether the sensed pressure (P0) is greater than or equal to a predetermined threshold pressure (P1). thresh ) (e.g., 15 psi) (block 208). thresh If the pressure (P0) exceeds a predetermined threshold pressure (P0), the plunger is dead-ended, the initialization process is complete, and the user fill volume is determined (block 210) to be the initial position (X0) of the pump drive mechanism, which is 310U in the example of FIG. thresh ) (block 208), the pump drive 37 determines whether the measured pressure exceeds P thresh Since the pusher 44 must be able to advance beyond the maximum allowable speed without stalling, it is possible that there may be an error in the delivery device operation (block 212).

[0039] 6, if one step increment has been completed (block 206), the microcontroller 31 analyzes both pressures (P0 and P1) to determine whether each of the pressures (P0 and P1) is above a predetermined threshold pressure (P thresh ) (block 214). thresh), the initialization process is complete and the user fill volume is determined by subtracting the current position (X1) of the pump drive 37 at one step increment from the initial position (Xo) (block 216). In an exemplary embodiment of the present disclosure, the user fill volume is determined by subtracting 0.05U from 310U when one step increment of the pump drive 37 is completed. If the pressures (P0 and P1) exceed the threshold pressure (P thresh ), the microcontroller 31 continues to advance the pusher 44 connected to the pump drive mechanism 37 in step increments (block 218).

[0040] As explained above, the microcontroller 31 is programmed to continue to determine the user fill volume of the medication delivery device according to the algorithm of Figure 6. The pump drive advances the pusher by one step increment (block 218) and the microcontroller 31 checks whether the step increment is complete (block 220). When the pump drive completes one step increment, the microcontroller 31 calculates both the pressure (P n and P n-1 ) at a given threshold pressure (P thresh ) (block 224). If a step increment has not been completed in block 220, the microcontroller 31 checks whether the pump drive can push against the threshold pressure without stalling (block 222). In block 224, both pressures (P n and P n-1 ) respectively, the threshold pressure (P thresh), the microcontroller 31 determines that the initialization process is complete, and the user fill volume is calculated by subtracting the current position (Xn) from the initial position (Xo) of the pump drive mechanism. For example, in an exemplary embodiment of the present disclosure, the user fill volume is calculated by subtracting 0.05*n from the initial position (e.g., 310U) (block 226). In particular, in the exemplary implementation, the on-step increment of the pusher 44 corresponds to a volume displacement of 0.05U, as described with reference to FIG. 6.

[0041] Additionally, in block 224, both pressures (P n and P n-1 ) is the threshold pressure (P thresh ), the microcontroller 31 also n and P n-1 ) is (P0 and P delta ) (e.g., P delta =3 psi) (block 228). n and P n-1 ) is the pressure (P0 and P delta ), the microcontroller 31 determines that the initialization process is complete and the user fill volume is calculated by subtracting the current position (Xn) from the initial position (Xo) of the pump drive mechanism. For example, in an exemplary embodiment of the present disclosure, the user fill volume is calculated by subtracting 0.05*n from the initial position (e.g., 310U) (block 230). As shown in FIG. 6, if the predetermined threshold pressure has not been reached, the microcontroller 31 begins incrementing according to procedure 200. It continues incrementing until the pressure increases. When the pressure criterion is met, the microcontroller 31 stops incrementing and determines the number of remaining increments that correspond to the user fill volume by subtracting the current position from the initial position of the pump drive mechanism.

[0042] FIG. 7 shows pressure data measurements in the reservoir of various drug delivery devices, non-limiting examples of such devices are described above with reference to FIGS. 1-5C, and perform an initialization process according to the procedure of FIG. 6. When the drive train of the drug delivery device is incrementing, the drug delivery device takes a pressure reading at each increment. As shown in the example of FIG. 7, the pressure data measurements have little noise before the pusher connected to the pump drive mechanism is selectively coupled to the plunger, and also have a very clear inflection point when the pusher is fully engaged with the plunger. Thereafter, the pressure data measurements show that the pressure inside the reservoir rises instantly and is detectable, and further, that the pressure continues to rise without leaking or flowing through the downstream air membrane. Thus, as explained above, a user fill volume detection system in the drug delivery device can determine the user fill volume by measuring the increment of the pump drive mechanism by the pressure sensed inside the reservoir.

[0043] It should be understood that the exemplary embodiments described herein may allow for operational variations and alternative configurations for measuring user fill volume. The user fill volume detection system may use any pressure sensing method or alternatives such as current sensing, force sensing, membrane sensing, or torque sensing. For example, instead of setting a pressure limit, the algorithm of FIG. 6 may be applied to a current signal instead of a pressure signal, since the current should correspond to pressure / force / torque, etc. Another variation may involve using a flow sensor instead of a pressure sensor. When utilizing a flow sensor, the device is required to have a known downstream compliance or optional leak vent. The flow sensor does not read flow until the pump drive engages the plunger, at which point there is flow through the sensor, expanding the downstream flow path, or there is flow through the downstream vent, indicating that the system is fully engaged and primed.

[0044] According to an exemplary implementation, another variation can be constructed, for example, by setting up a system similar to that described above with reference to Figures 5A-5C, where instead of measuring pressure, the pump drive increments during filling until the entire drive stalls. The fill volume can be calculated insofar as the drive train dead-ends and a stall condition can only occur when the system is pressurized.

[0045] Another exemplary embodiment of the user fill volume detection system of the present disclosure provides an implementation configuration such as that determined above with reference to FIGS. 1-7, in which medication is dispensed from a chamber using a syringe-like plunger action, and can be described with reference to FIG. 8. In the exemplary implementation, prior to filling the device, the plunger 36 is disconnected from the pusher 44 and positioned at the front (distal end) 27 (empty position) of the reservoir 26. As fluid is injected into the device 10, the plunger 36 is pushed back as it fills the reservoir 26, which is eventually stopped when it reaches the pusher 44. The volume of fluid the reservoir can accept can be adjusted by pre-positioning the pusher 444 at a desired maximum volume.

[0046] 8, an exemplary implementation is described with reference to a chart 300 illustrating how a user can measure and communicate a fill volume to a drug delivery device 10 according to an exemplary embodiment of the present disclosure. In step 301, a user has a drug delivery device 10, and in step 302, a user having a controller installed in a personal device 60 (e.g., an application installed on a smartphone (see FIG. 4)) to wirelessly communicate with the drug delivery device 10, pairs the controller with the electronics subsystem 106 of the drug delivery device 10.

[0047] In step 303, the user further inputs the amount of the intended fill volume according to the instructions of the controller installed in the personal device 60. In step 304, the controller, having received the information of the fill volume, records the volume and commands the drug delivery device 10 to move the pusher 44 to a location that limits the fill volume to the desired amount. Before filling the delivery device 10, the plunger 36 is disconnected from the pusher rod and is located at the distal end 27 of the reservoir 26, which is the empty position of the plunger 36 as shown in FIG. 5A. Finally, in step 305, the user (or patient) can now fill the drug delivery device 10 by the syringe 24 or a filling device, whereby detection of the fill volume in the drug delivery device is achieved. When the liquid drug is injected into the drug delivery device 10, the plunger 36 is pushed back as it fills the reservoir, and is eventually stopped when it reaches the pusher rod. Additionally, steps 303 and 304 allow for adjustment of the volume the reservoir can accommodate by pre-positioning the pusher rod at a desired maximum volume.

[0048] According to yet another exemplary embodiment of the present disclosure, instead of or in conjunction with increasing pressure or generating flow, contact of the plunger 36 with the pusher 44 can be detected. In an exemplary implementation, any pressure sensing method or alternative such as current sensing, force sensing, membrane deflection, or torque sensing can be used. For example, a current can correspond to pressure / force / torque, etc., so instead of setting a pressure limit, the processing and hardware described with reference to FIG. 6 can be applied to a current signal instead of a pressure signal.

[0049] For example, when measuring force / torque / current, a drug delivery device (e.g., insulin delivery device) should see an increase in the signal when the pusher contacts the plunger, since the pump drive mechanism must now push against the plunger friction force in addition to the torque / force that has been raised to that point. This detection system can have the advantage that no pressure increase is required. Furthermore, another potential advantage of such a design is that it does not rely on a downstream path being selectively blocked. For example, such a method of fill detection would still work if the drug delivery device was filled through a dosing needle.

[0050] As described above, exemplary embodiments of the present disclosure provide system components and methods for detecting a user fill volume of a fluid medication in a pump infusion system. Such user fill volume detection can be implemented using existing infusion pump systems present in most medication delivery devices. Furthermore, user fill volume detection can be performed without additional components. For example, a microcontroller or other processing device for controlling pump operation can be further controlled to determine the user fill volume by sensing the pressure of a reservoir present in the device.

[0051] Having an integrated method of detecting fill volume using existing hardware provides a technical solution to the above technical problem, which eliminates the need for users to keep track of and carry separate filling devices to perform equivalent system functions. For example, embodiments of the present disclosure can be applied to and have advantages over some known devices that use a switch that is triggered during filling with a specific fill amount (e.g., 60U). By monitoring the switch during dispensing, it detects when the switch is disengaged. From the disengagement point, such devices count down toward zero / empty. Due to this design, a drawback of such devices is that the fill volume cannot be calculated and the fill volume cannot be confirmed by the user. It also cannot display the remaining volume to the user until the remaining volume is equal to or less than the volume corresponding to the switching point. The accuracy of the fill / empty detection of such devices depends on the accuracy of the switching. In the examples described herein, the accuracy of the fill volume detection can be determined by a dose encoding component configured to be accurate to ensure the accuracy of the injected dose. Furthermore, other exemplary devices can be configured without fill volume feedback, leaving it up to the user to accurately input the fill volume information. Arrangements for measuring fill volume as described in the exemplary implementations above can be advantageous for such devices as well.

[0052] Components of the illustrative devices, systems, and methods used by the illustrated embodiments may be implemented at least in part in digital electronic circuitry, analog electronic circuitry, or in computer hardware, firmware, software, or in combinations thereof. These components may be implemented as a computer program product, such as a computer program, program code, or computer instructions tangibly embodied in an information carrier or machine-readable storage device for execution by, or to control the operation of, a data processing apparatus, such as a programmable processor, a computer, or multiple computers.

[0053] The computer program may be written in any form of programming language, including compiled or interpreted languages, and may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. The computer program may be deployed to be executed on one computer, or on multiple computers at one site, or distributed across multiple sites and interconnected by a communication network. Also, functional programs, codes, and code segments for achieving the illustrative embodiments may be readily interpreted by a skilled programmer in the art to which the illustrative embodiments pertain, as being within the scope of the claims illustrated by the illustrative embodiments. The method steps associated with the illustrative embodiments may be performed by one or more programmable processors that execute computer programs, codes, or instructions to perform functions (e.g., by operating on input data and / or generating output). The method steps may also be performed by special purpose logic circuitry, such as a field programmable gate array (FPGA), or, for example, an application specific integrated circuit (ASIC), and the apparatus of the illustrative embodiments may be implemented as a special purpose logic circuit.

[0054] The various illustrative logic blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed by a general purpose processor, a digital signal processor (DSP), an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0055] Processors suitable for executing computer programs include, by way of example, both general-purpose and special-purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a processor receives instructions and data from a read-only memory or a random access memory, or both. The essential elements of a computer are a processor for executing instructions, and one or more memory devices for storing instructions and data. Typically, a computer also includes one or more mass storage devices for storing data, such as magnetic, magneto-optical, or optical disks, or is operatively coupled to receive data from or transfer data to the device, or both. Information carriers suitable for embodying computer program instructions and data include, by way of example, all forms of non-volatile memory, including semiconductor memory devices, such as electrically programmable read-only memories or ROMs (EPROMs), electrically erasable programmable ROMs (EEPROMs), flash memory devices, and data storage disks (e.g., magnetic disks, internal hard disks, or removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks). The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0056] Those skilled in the art will appreciate that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, symbols and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0057] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and design constraints imposed on the overall system. Skilled persons may implement the described functionality in various ways for each specific application, but such implementation decisions should not be interpreted as causing a departure from the scope of the claims as illustrated by the illustrative embodiments. The software modules may reside in a random access memory (RAM), flash memory, ROM, EPROM, EEPROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor, such that the processor can read information from the storage medium and write information to the storage medium. In the alternative, the storage medium may be integral to the processor, or in other words, the processor and the storage medium may reside in an integrated circuit or may be implemented as discrete components.

[0058] Computer-readable non-transitory media includes all types of computer-readable media, including magnetic storage media, optical storage media, flash media, and solid-state storage media. It should be understood that the software may be installed in and sold with a central processing unit (CPU) device. Alternatively, the software may be obtained and loaded into the CPU device, including obtaining the software through a physical medium or through a distribution system, including, for example, from a server owned by the software creator or from a server not owned but used by the software creator. For example, the software may be stored on a server for distribution over the Internet.

[0059] The description and figures presented above are intended as examples only and are not intended to limit the illustrative embodiments in any manner, except as set forth in the claims. It is specifically noted that one skilled in the art could readily combine the various technical aspects of the various elements of the various illustrative embodiments described above in numerous other ways, all of which are considered to be within the scope of the claims.

Claims

1. an infusion pump system including a reservoir, a fluid path between the reservoir and an insertion mechanism, a plunger inside the reservoir, and a pump drive mechanism coupled to the reservoir; a processing device configured to determine a user fill volume of the fluidic medicament by analyzing a location of the plunger relative to the reservoir when filling of the fluidic medicament is completed; A drug delivery device comprising:

2. The processing device is configured to determine the location of the plunger by sensing a pressure inside the reservoir. The drug delivery device of claim 1 .

3. a pressure sensor for sensing the pressure inside the reservoir. A drug delivery device according to claim 1 or 2.

4. The flow path is selectively blocked when the filling of the fluid medicament is complete. A drug delivery device according to any one of claims 1 to 3.

5. The processing device determines an initial position of the pump drive mechanism. A drug delivery device according to any one of claims 1 to 4.

6. The processing device activates the pump drive mechanism to move the plunger relative to the reservoir, and the processing device measures the movement of the pump drive mechanism from the initial position to when the filling of the fluid medicament is completed. The drug delivery device of claim 5.

7. The current position of the pump drive mechanism is determined when the pressure inside the reservoir exceeds a threshold pressure. A drug delivery device according to claim 5 or 6.

8. The processing device is configured to determine the user fill volume by calculating a difference between the initial position and the current position of the pump drive mechanism. The drug delivery device of claim 7.

9. The infusion pump system further includes a pusher connected to the pump drive mechanism and selectively coupled to the plunger inside the reservoir. A drug delivery device according to any one of claims 1 to 8.

10. the plunger is decoupled from the pump drive mechanism such that the plunger is free to move inside the reservoir while the fluid medicament is filling the reservoir. A drug delivery device according to any one of claims 1 to 9.

11. The processing device is configured to determine the location of the plunger by sensing a current in the pump drive mechanism. The drug delivery device of claim 1 .

12. The processing device is configured to determine the location of the plunger by sensing a force applied to the pump drive mechanism. The drug delivery device of claim 1 .

13. The processing device is configured to determine the location of the plunger by sensing a torque applied to a motor of the pump drive mechanism. The drug delivery device of claim 1 .

14. The processing device is configured to determine the location of the plunger by sensing a flow of the fluid medicament in the flow path. The drug delivery device of claim 1 .

15. a flow sensor for sensing the flow of the fluid medicament in the flow path.

15. A drug delivery device according to claim 1 or 14.

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