System and method for pressure sensor-based bubble detection for a drug delivery device

Abstract

A drug delivery device can include a pressure sensor, a microprocessor, a fluid pathway including a reservoir, a pump downstream of the reservoir, and / or a fluid line downstream of the pump. The reservoir can be configured to receive fluid, and the pump can be configured to deliver fluid from the reservoir to the fluid line. The pressure sensor can be configured to measure the pressure within the fluid pathway downstream of the pump. The microcontroller can receive from the pressure sensor the pressure measured in the fluid pathway downstream of the pump when fluid is delivered to the fluid line, and based on the pressure measured in the fluid pathway, determine whether the fluid delivered to the fluid line contains air bubbles, and can be programmed and / or configured to control an output device to provide an indication associated with the determination of air bubbles.

Description

Technical Field

[0001] The present disclosure relates to devices and methods for pressure sensor-based bubble detection for drug delivery devices.

Background Art

[0002] Cross-Reference to Related Applications This application claims priority to U.S. Utility Patent Application No. 17 / 859,627, filed July 7, 2022, entitled "Systems and Methods for Pressure Sensor-Based Bubble Detection for Drug Delivery Devices," the entire disclosure of which is hereby incorporated by reference in its entirety.

[0003] Wearable medical devices, such as autoinjectors, have the advantage of providing treatment to patients in locations away from clinical facilities and / or while individually worn under a patient's clothing. A wearable medical device can be applied to a patient's skin and configured to automatically administer a dose of a pharmaceutical composition within a predetermined period after application of the wearable medical device to the patient's skin, such as after a delay of, for example, 27 hours. After the device has administered the pharmaceutical composition to the patient, the patient can subsequently remove and discard the device.

[0004] In the context of fluid injection or infusion, some drugs can be prescribed to be administered according to a tightly controlled dosing schedule (e.g., an accurate dose can be prescribed to be delivered at a controlled timing, etc.). Infusion devices typically enable a controlled flow rate and dosing schedule based on volumetric administration, and the system imposes a known volumetric displacement of the fluid being administered. Exemplary systems that enable volume-based control of administration are syringe pumps, oscillatory rotary pumps, systems with moving pistons, peristaltic pumps, and membrane and diaphragm pumps.

[0005] A subset of these pumps functions based on a "dosing chamber element" that is cyclically filled and discharged. The particularity of these systems is that the fluid path upstream of the pump does not communicate directly with the path downstream of the pump, which allows different pressures to be established in their respective fluid paths.

[0006] The presence of gas or bubbles in the fluid is a ubiquitous problem in the field of accurate dosing because these bubbles impair the control of the volume of the drug administered by occupying a portion of the volume passing through the fluid path, which can lead to underdosing and / or have an adverse effect on the treatment being administered. Solutions to bubbles exist in the form of bubble traps and optical or ultrasonic bubble detection systems. However, these systems impose the addition of components to the fluid path or the use of sensors that can be expensive and / or consume significant power, which can be of particular concern for wearable devices.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

[0008] Accordingly, an improved system, device, product, apparatus, and / or method for bubble detection in a drug delivery device is provided.

[0009] According to some non - limiting embodiments or aspects, a fluid path including a reservoir, a pump downstream of the reservoir, and a fluid line downstream of the pump, wherein the reservoir is configured to receive fluid and the pump is configured to deliver fluid from the reservoir to the fluid line, a pressure sensor configured to measure the pressure of the fluid path downstream of the pump, and an output device that receives from the pressure sensor the pressure measured in the fluid path downstream of the pump when fluid is delivered to the fluid line and is controlled to determine whether the fluid delivered to the fluid line contains air bubbles based on the pressure measured in the fluid path downstream of the pump when fluid is delivered to the fluid line and to provide an indication related to the determination of whether the fluid delivered to the fluid line contains air bubbles, a drug delivery device is provided.

[0010] In some non - limiting embodiments or aspects, the pump includes a dosing chamber and is configured to periodically (i) pump the reservoir using the dosing chamber that is in fluid communication with the reservoir and not in fluid communication with the fluid line, and (ii) fluidly connect the dosing chamber to the fluid line such that fluid is delivered to the fluid line when the dosing chamber is fluidly connected to the fluid line.

[0011] In some non - limiting embodiments or aspects, the microcontroller is further programmed and / or configured to receive from the pressure sensor the pressure measured in the fluid path downstream of the pump before fluidly connecting the dosing chamber to the fluid line and to determine a baseline pressure based on the pressure measured in the fluid path downstream of the pump before fluidly connecting the dosing chamber to the fluid line, and the microcontroller is programmed and / or configured to determine whether the fluid delivered to the fluid line contains air bubbles based on the pressure measured in the fluid path downstream of the pump and the baseline pressure when the fluid is delivered to the fluid line.

[0012] In some non-limiting embodiments or aspects, the microcontroller compares the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold pressure, and determines whether the fluid delivered to the fluid line contains bubbles by determining that the fluid delivered to the fluid line contains bubbles in response to the pressure measured in the fluid path downstream of the pump when the fluid delivered to the fluid line meets the threshold pressure. The microcontroller is programmed and / or configured to determine whether the fluid delivered to the fluid line contains bubbles.

[0013] In some non-limiting embodiments or aspects, the microcontroller determines a rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, compares the rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold rate of change, and determines that the fluid delivered to the fluid line contains bubbles in response to the rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid delivered to the fluid line meets the threshold rate of change. The microcontroller is programmed and / or configured to determine whether the fluid delivered to the fluid line contains bubbles.

[0014] In some non-limiting embodiments or aspects, the microcontroller receives the pressure associated with the fluid path upstream of the pump and, based on the pressure associated with the fluid path upstream of the pump, further programs and / or configures to determine at least one of the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, the dimensions of the fluid path, the volume of bubbles contained in the fluid delivered to the fluid line, the volume of the fluid delivered to the fluid line, or any combination thereof.

[0015] In some non-limiting embodiments or aspects, the microcontroller determines pressure fluctuations over a period of time based on the pressure measured in the fluid path downstream of the pump when fluid is delivered to the fluid line, compares the pressure fluctuations over a period of time to a threshold fluctuation, and determines that the fluid delivered to the fluid line contains bubbles in response to the pressure fluctuations over a period of time satisfying the threshold fluctuation, and is programmed and / or configured to determine whether the fluid delivered to the fluid line contains bubbles.

[0016] In some non-limiting embodiments or aspects, the microcontroller is further programmed and / or configured to determine at least one of the volume of bubbles contained in the fluid delivered to the fluid line, the volume of fluid delivered to the fluid line, or any combination thereof, based on the pressure fluctuations over a period of time.

[0017] In some non-limiting embodiments or aspects, the pressure sensor includes at least one of an absolute pressure sensor, a differential pressure sensor, or any combination thereof.

[0018] In some non-limiting embodiments or aspects, the microcontroller receives from the pressure sensor the pressure measured in the fluid path downstream of the pump during priming of the pump, and is further programmed and / or configured to determine whether the pump is fully primed based on the pressure measured in the fluid path downstream of the pump during priming of the pump.

[0019] According to some non-limiting embodiments or aspects, a pressure sensor-based bubble detection method for a drug delivery device is provided that includes a fluid path including a reservoir configured to receive a fluid, a pump downstream of the reservoir, and a fluid line downstream of the pump. The method includes delivering a fluid from the reservoir to the fluid line using the pump, measuring a pressure in the fluid path downstream of the pump using a pressure sensor, receiving, using a microcontroller, the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, determining, using the microcontroller, whether the fluid delivered to the fluid line contains bubbles based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, and controlling, using the microcontroller, an output device to provide an indication related to a determination of whether the fluid supplied to the fluid line contains bubbles.

[0020] In some non-limiting embodiments or aspects, the pump includes a dosing chamber, and the pump is configured to periodically (i) pump the reservoir using the dosing chamber that is in fluid communication with the reservoir and not in fluid communication with the fluid line, and (ii) fluidly connect the dosing chamber to the fluid line such that fluid is delivered to the fluid line when the dosing chamber is fluidly connected to the fluid line.

[0021] In some non-limiting embodiments or aspects, the method further includes measuring, using a pressure sensor, a pressure in the fluid path downstream of the pump before fluidly connecting the dosing chamber to the fluid line, and determining a baseline pressure based on the pressure measured in the fluid path downstream of the pump before fluidly connecting the dosing chamber to the fluid line, and whether the fluid delivered to the fluid line contains bubbles is determined based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line and the baseline pressure.

[0022] In some non-limiting embodiments or aspects, determining whether the fluid delivered to the fluid line contains bubbles includes comparing the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold pressure, and determining that the fluid delivered to the fluid line contains bubbles in response to the pressure measured in the fluid path downstream of the pump when the fluid is delivered to a fluid line that meets the threshold pressure.

[0023] In some non-limiting embodiments or aspects, determining whether the fluid delivered to the fluid line contains bubbles includes determining a rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; comparing the rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold rate of change; and determining that the fluid delivered to the fluid line contains bubbles in response to the rate of change associated with the pressure measured in the fluid path of the pump when the fluid is delivered to a fluid line that meets the threshold rate of change.

[0024] In some non-limiting embodiments or aspects, the method further includes receiving, using a microcontroller, the pressure associated with the fluid path upstream of the pump, and determining, using the microcontroller, at least one of the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, based on the pressure associated with the fluid path upstream of the pump, the dimensions of the fluid path, the volume of bubbles contained in the fluid delivered to the fluid line, the volume of the fluid delivered to the fluid line, or any combination thereof.

[0025] In some non-limiting embodiments or aspects, determining whether the fluid delivered to the fluid line contains bubbles includes determining pressure fluctuations over a period of time based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, comparing the pressure fluctuations over a period of time to a threshold fluctuation, and determining that the fluid delivered to the fluid line contains bubbles over a period of time in response to the pressure fluctuations over a period of time satisfying the threshold fluctuation.

[0026] In some non-limiting embodiments or aspects, the method further includes determining, using a microcontroller, at least one of the volume of bubbles contained in the fluid delivered to the fluid line, the volume of the fluid delivered to the fluid line, or any combination thereof, based on the pressure fluctuations over a period of time.

[0027] In some non-limiting embodiments or aspects, the method further includes measuring, using a pressure sensor, another pressure in the fluid path downstream of the pump during priming of the pump, receiving, using a microcontroller, from the pressure sensor the another pressure measured in the fluid path downstream of the pump during priming of the pump, and determining whether the pump is fully primed based on the pressure in the fluid path measured downstream of the pump during priming of the pump.

[0028] According to some non-limiting embodiments or aspects, a computer program product for pressure sensor-based bubble detection for a drug delivery device is provided that includes a microcontroller, a pressure sensor, and a fluid path including a reservoir configured to receive a fluid, a pump downstream of the reservoir, and a fluid line downstream of the pump. When the computer program product is executed by the microcontroller, the microcontroller is caused to control the pump to deliver the fluid from the reservoir to the fluid line, control the pressure sensor to measure the pressure in the fluid path downstream of the pump when the fluid is delivered to the fluid line, receive the pressure measured in the fluid path downstream of the pump from the pressure sensor when the fluid is delivered to the fluid line, and based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, determine that the fluid delivered to the fluid line contains bubbles and control an output device to provide a display associated with the determination as to whether the fluid delivered to the fluid line contains bubbles, and includes at least one non-transitory computer-readable medium including program instructions for causing the above.

Brief Description of the Drawings

[0029] The above and other features and advantages of the present disclosure, and the manner of achieving them, will become more apparent by reference to the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, and the present disclosure itself will be better understood.

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[0030] Corresponding reference numerals indicate corresponding parts throughout several views. The examples presented herein illustrate exemplary embodiments of the present disclosure and such examples should not be construed as limiting the scope of the present disclosure in any way.

Mode for Carrying Out the Invention

[0031] Spatial or directional terms such as "left", "right", "inner", "outer", "above", "below", etc. should not be considered limiting since aspects or embodiments of the present disclosure can envision various alternative directions.

[0032] All numbers used in this specification and the claims are to be understood as being modified in all instances by the term "about". By "about" is meant a range of plus or minus 10 percent of the recited value. As used in this specification and the claims, the singular forms of "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. The terms "first", "second", etc. are not intended to refer to any particular order or chronology, but rather to distinguish different conditions, characteristics, or elements. "At least" means "greater than or equal to".

[0033] Referring to FIGS. 1 - 3, drug delivery device 10 includes reservoir 12, power source 14, insertion mechanism 16, control electronics 18, cover 20, and substrate 22. In one aspect or embodiment, drug delivery device 10 is a wearable auto - injector such as an insulin or bone marrow stimulant administration device. Drug delivery device 10 can be attached to a patient's skin and can operate to inject a pharmaceutical composition from reservoir 12 into the patient. Drug delivery device 10 may be pre - filled with a pharmaceutical composition or may be filled with a pharmaceutical composition by the patient or a medical professional prior to use.

[0034] Drug delivery device 10 is configured to administer a pharmaceutical composition, e.g., a dosage of any desired drug, into a patient's body by subcutaneous injection at a slow and controlled injection rate. An exemplary duration for the administration achieved by drug delivery device 10 can range from about 5 minutes to about 60 minutes, but is not limited to this exemplary range. An exemplary volume of the pharmaceutical composition administered by drug delivery device 10 can range from about 0.1 milliliters to about 10 milliliters, but is not limited to this exemplary range. The amount of the pharmaceutical composition administered to the patient can be adjusted.

[0035] Referring again to FIGS. 1 - 3, in one aspect or embodiment, power source 14 is a DC power source including one or more batteries. Control electronics 18 includes a microcontroller 24, sensing electronics 26, a pump and valve controller 28, sensing electronics 30, and deployment electronics 32 that controls the operation of drug delivery device 10. Drug delivery device 10 includes a fluidics subsystem including a reservoir 12, a volume sensor 34 for reservoir 12, a reservoir fill port 36, and a metering system 38 including a pump and valve actuator 40 and a pump and valve mechanism 42. The fluidics subsystem may further include an occlusion sensor 44, a deployment actuator 46, a cannula 48 for insertion into a patient's skin, and a fluid line 50 in fluid communication between reservoir 12 and cannula 48. In one aspect or embodiment, occlusion sensor 44 includes a pressure sensor such as pressure sensor 54 described in more detail herein with respect to FIG. 4. In one aspect or embodiment, insertion mechanism 16 is configured to move cannula 48 from a retracted position where the entire cannula 48 is disposed inside device 10 to an extended position where cannula 48 extends outside of device 10. Drug delivery device 10 may operate in the same manner as described in Patent Document 1 of Pizzochero et al., which is incorporated herein by reference.

[0036] In one aspect or embodiment, the fluid path is formed by reservoir 12, a pump and valve mechanism 42 downstream of reservoir 12, and a fluid line 50 downstream of pump and valve mechanism 42. For example, reservoir 12 may be configured to receive fluid, and pump and valve mechanism 42 may be configured to deliver fluid from reservoir 12 to fluid line 50.

[0037] Referring to FIG. 4, in one aspect or embodiment, the pump and valve mechanism 42 includes a dosing chamber 52. The pump and valve mechanism 42 is configured to periodically (i) pump using a dosing chamber that is in fluid communication with the reservoir 12 and not in fluid communication with the reservoir 12, and (ii) fluidly connect the dosing chamber 52 that is not in fluid communication with the reservoir 12 to the fluid line 12 (e.g., such as the dosing chamber 52 that is not in fluid communication with the reservoir 12). For example, the pump and valve mechanism 42 may pump the reservoir 12 with the dosing chamber 52 in a state where the dosing chamber 52 is in fluid communication with the reservoir 12 and not in fluid communication with the fluid line 50, and fill the dosing chamber 52 with fluid from the reservoir 12. The pump and valve mechanism 42 may also connect the dosing chamber 52 to the fluid line 50, empty the dosing chamber 52 of fluid, and deliver the fluid to the fluid line 50 (e.g., such as when the dosing chamber 52 is not in fluid communication with the reservoir 12). In this way, the fluid path upstream of the pump and valve mechanism 42 (e.g., upstream of the dosing chamber 52) is not in direct fluid communication with the fluid path downstream of the pump and valve mechanism 42, allowing different pressures to be established in their respective upstream and downstream fluid paths.

[0038] Referring further to FIG. 4, the drug delivery device 10 may include a pressure sensor 54. The pressure sensor 54 may be configured to measure the pressure within a fluid path formed by the reservoir 12, the pump and valve mechanism 42 downstream of the reservoir 12, and the fluid line 50 downstream of the pump and valve mechanism 42. The pressure sensor 54 may be within the fluid path downstream of the pump and valve mechanism 42 and / or within the fluid path upstream of the pump and valve mechanism 42. For example, the pressure sensor 54 may be configured to measure the pressure within the fluid path downstream (e.g., downstream of the dosing chamber 52, etc.) and / or upstream (e.g., upstream of the dosing chamber 52, etc.) of the pump and valve mechanism 42. The pressure sensor 54 may include at least one of an absolute pressure sensor, a differential (e.g., gauge, etc.) pressure sensor, or any combination thereof. The pressure sensor 54 may be miniaturized, may have high resolution, may be cost-effective, and / or may be optimized for low power consumption.

[0039] The microcontroller 24 receives, from the pressure sensor 54, the pressure measured in the fluid path downstream of the pump and valve mechanism 42 when fluid is delivered to the fluid line (e.g., when the dosing chamber 52 is in fluid communication with the downstream fluid path including the fluid line 50), and based on the pressure measured in the fluid path downstream of the pump and valve mechanism 42 when fluid is delivered to the fluid line 50 (e.g., the pressure measured in the dosing chamber 52 when in fluid communication with the downstream fluid path including the fluid line 50), determines whether the fluid delivered to the fluid line contains air bubbles and / or can be programmed and / or configured to control an output device (e.g., a display, a light-emitting diode (LED), a speaker, etc.) to provide an indication associated with the determination of whether the fluid delivered to the fluid line contains air bubbles. The output device may be included in the drug delivery device 10 and / or integrated with the drug delivery device 10 and / or the output device may be included in and / or integrated with an external device external to the drug delivery device 10 and in communication (e.g., wireless and / or radio communication, etc.) such as a remote computing device and / or a wireless controller (WC) 500 as described in Patent Document 1 of Pizzochero et al., which is incorporated herein by reference.

[0040] In this manner, and referring also to FIGS. 5A, 5B and 6 - 9, non - limiting embodiments or aspects of the present application detect the pressure characteristics of gas bubbles being pumped through a fluid system by using the higher compressibility of gas compared to liquid in combination with a pressure sensor disposed downstream of a pump system having at least a portion of a fluid path connected to a fluid line 50 (e.g., an injection port, etc.) and a periodic application of a known volume change within a dosing chamber 52. For example, when a pump and valve mechanism 42 imposes a known volume change within a known period, the pressure in the downstream fluid path, downstream of the dosing chamber 52, is expected to increase by at least a known value as a result of fluid movement within the fluid line 50. However, the presence of bubbles within the pumped volume suppresses the pressure increase and can be reliably detected by the pressure sensor 54. Further, the additional compliance of the bubbles within the dosing chamber 52, together with the pressure difference between the upstream and downstream fluid paths with respect to the dosing chamber 52, can cause a pressure change when the dosing chamber comes into fluid communication with the downstream fluid line 50. If the pressure is higher in the downstream fluid path, the pressure drop can be identified as a bubble or a signature or presence of a bubble. Using the pressure in the upstream fluid path, either by direct measurement or inference (e.g., known to be atmospheric pressure, etc.), the volume of the bubble can be determined based on at least one of the pressure change in the downstream fluid path, the volume of the fluid system, the dimensions of the fluid system, the rheological characteristics of the fluid within the fluid line, or any combination thereof.

[0041] In one aspect or embodiment, the microcontroller 24 compares the pressure measured in the fluid path downstream of the pump and valve mechanism 42 (e.g., the maximum or peak pressure achieved in the dosing chamber 52 that is in fluid communication with the downstream fluid path including the fluid line 50, the dosing chamber 52 being fluidly connected to the downstream fluid path including the fluid line 50 such that the pressure in the downstream fluid path changes or fluctuates over a period of time) when fluid is delivered to the fluid line 50 to a threshold pressure (e.g., threshold peak pressure, threshold pressure change or fluctuation, etc.). By doing so, when fluid that meets the threshold pressure is sent to the fluid line 50, the microcontroller 24 is programmed and / or configured to determine whether the fluid delivered to the fluid line 50 contains air bubbles in response to the pressure measured in the fluid path downstream of the pump and valve mechanism 42. For example, the microcontroller 24 compares the peak pressure reached in the pump (e.g., when the dosing chamber 52 of the pump and valve mechanism 42 is connected to the downstream fluid path) to the threshold pressure, and in response to the peak pressure meeting the threshold pressure (e.g., in response to the peak pressure being below the threshold pressure, in response to the pressure or change or fluctuation being above the threshold pressure change, etc.), it can be determined that the fluid delivered to the fluid line 50 contains air bubbles.

[0042] In one aspect or embodiment, when fluid is delivered to fluid line 50 (e.g., when the dosing chamber 52 of the pump and valve mechanism 42 is connected to the downstream fluid path), the microcontroller 24 determines a rate of change associated with the pressure measured in the fluid path downstream of the pump when fluid is delivered to the fluid line based on the pressure measured in the fluid path downstream of the pump and valve mechanism 42, compares the rate of change associated with the pressure measured in the fluid path downstream of the pump and valve mechanism 42 when fluid is delivered to fluid line 50 with a threshold rate of change, and in response to the rate of change associated with the pressure measured in the fluid path downstream of the pump and valve mechanism 42 when fluid is delivered, determines that the fluid delivered to fluid line 50 contains bubbles by determining that the fluid line 50 meets the threshold rate of change, and is programmed and / or configured to determine whether the fluid delivered to the fluid line contains bubbles. For example, the microcontroller 24 may compare a rate of change (e.g., a rate of pressure increase, a rate of pressure decrease, a rate of pressure increase, a rate of pressure decrease, etc.) associated with the pressure measured in the fluid path downstream of the pump and valve mechanism 42 in the pump with a threshold rate of change, and in response to the measured rate of change meeting the threshold rate of change (e.g., falling below a threshold velocity, etc.), determine that the fluid delivered to fluid line 50 contains bubbles.

[0043] In one aspect or embodiment, the microcontroller 24 is further programmed and / or configured to receive, from the pressure sensor 54, the pressure measured in the fluid path downstream of the pump and valve mechanism 42 before connecting the dosing chamber 52 to the fluid line 50 (e.g., before initiating a change in the volume of the downstream fluid path), and to determine a baseline pressure based on the pressure measured in the fluid path downstream of the pump and valve mechanism 42 before connecting the dosing chamber 52 to the fluid line 50. In such an example, the microcontroller 24 can be programmed and / or configured to determine whether the fluid delivered to the fluid line 50 contains air bubbles based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line 50 and the baseline pressure. For example, the measured pressure signature in the fluid path can be offset by a baseline pressure signature defined by the value of the pressure measured before connecting the dosing chamber 52 to the downstream fluid path. In this way, non-limiting embodiments or aspects of the present application can compensate for the effect on the pressure signature due to the mechanical compliance of the pump system (e.g., spring effect, component deformability, mechanical backlash, etc.) when the dosing chamber 52 is connected to the downstream fluid path. For example, the pressure signature measured when the dosing chamber 52 is connected to the downstream fluid path can be utilized to detect the presence of air or gas in response to pressure fluctuations that exceed a predetermined threshold after compensation for system effects.

[0044] In one aspect or embodiment, the microcontroller 24 receives a pressure associated with the fluid path upstream of the pump and valve mechanism 42 (e.g., direct measurement by a pressure sensor 54 in the upstream fluid path or another pressure sensor, known atmospheric pressure, etc.), and based on the pressure associated with the fluid path upstream of the pump and valve mechanism 42, the pressure measured in the fluid path downstream of the pump and valve mechanism 42 when the fluid is delivered to the fluid line 50, and the dimensions of the fluid path (e.g., dimensions of the reservoir, dosing chamber 52, fluid line 50, upstream fluid path, and / or downstream fluid path, etc.), the volume of bubbles contained in the fluid delivered to the fluid line 50, the volume of the fluid delivered to the fluid line 50, or at least one of any combination thereof, and is further programmed and / or configured to determine. In this way, the pressure fluctuations can be used to determine the amount of gas and / or liquid delivered to the downstream fluid path.

[0045] In one aspect or embodiment, the microcontroller 24 is further programmed and / or configured to determine the relative volume of gas in the fluid delivered to the fluid line 50 by applying a combination of the Hagen - Poiseuille equation and known gas laws, taking into account at least one of fluid properties, pump regime, and dimensions of the fluid channel, to the measured pressure signature in the fluid path. For example, the microcontroller 24 can determine at least one of the volume of bubbles contained in the fluid delivered to the fluid line 50, the volume of the fluid delivered to the fluid line 50, or any combination thereof, based on the variation of pressure over a period of time.

[0046] In one aspect or embodiment, the microcontroller 24 receives from the pressure sensor 54 the pressure measured in the fluid path downstream of the pump and valve mechanism 42 during priming of the pump and valve mechanism 42, and is further programmed and / or configured to determine whether the pump and valve mechanism 42 is fully primed based on the pressure measured in the fluid path downstream of the pump and valve mechanism 42 during priming of the pump and valve mechanism 42. For example, the microcontroller 24 may compare the pressure measured in the fluid path downstream of the pump and valve mechanism 42 during priming of the pump and valve mechanism 42 (e.g., the maximum or peak pressure achieved during priming, the change or variation in pressure during priming, etc.) to a threshold priming pressure and determine that the downstream fluid path is fully primed in response to the measured priming pressure meeting the threshold priming pressure.

[0047] In one aspect or embodiment, the display related to determining whether the fluid delivered to the fluid line 50 contains air bubbles includes a notification of a successfully completed treatment (e.g., no air bubbles, etc.), a notification of a fault mode and / or air bubbles contained in the fluid delivered to the fluid line 50, a notification of the amount of fluid delivered to the fluid line, a notification of the amount of air bubbles in the fluid delivered to the fluid line, a notification of the priming state of the device 10 (e.g., fully primed, not fully primed, etc.), or any combination thereof.

[0048] In one aspect or embodiment, in response to the detection of air bubbles, the microcontroller 24 can adjust the circulation pump of the pump and valve mechanism 42 to compensate for the detected air bubbles (e.g., by adding additional pump cycles, by adjusting the duration of the pump cycle at a stage of the pump cycle, etc.). For example, the microcontroller 24 compares the volume of the air bubbles and / or the delivered fluid to a threshold or a predetermined volume, and in response to the volume of the gas bubbles and / or the delivered fluid satisfying the threshold or the predetermined volume, can be further programmed and / or configured to automatically adjust the circulation pump of the pump and valve mechanism 42 to compensate for the volume of the detected gas bubbles (e.g., by adding additional pump cycles, by adjusting the duration of the pump cycle at a stage of the pump cycle, etc.).

[0049] Referring to FIG. 10, in one aspect or embodiment, a process 1000 for pressure sensor-based air bubble detection of the drug delivery device 10 includes receiving fluid in the reservoir 12 (step 1002), delivering the fluid from the reservoir 12 to the fluid line 50 using the pump and valve mechanism 42 (step 1004), measuring the pressure in the fluid path downstream of the pump and valve mechanism 42 when the fluid is delivered to the fluid line 50 using the pressure sensor 54 (step 1006), receiving the pressure measured in the fluid path using the microcontroller 24 (step 1008), determining by the microcontroller 24 whether the fluid delivered to the fluid line 50 contains air bubbles based on the pressure measured in the fluid path (step 1010), and controlling an output device using the microcontroller 24 to provide an indication related to the determination of whether the fluid delivered to the fluid line 50 contains air bubbles (step 1012).

[0050] Accordingly, non-limiting embodiments or aspects of the present application can utilize potentially existing hardware within the pump system and / or can be used with containers such as flexible reservoir bags, rigid containers, and / or syringes, and can provide a drug delivery device having low manufacturing costs, extremely low power consumption, a compact size, and / or low computational power requirements.

[0051] Aspects or embodiments have been described in detail for purposes of illustration based on what are presently considered to be the most practical and preferred embodiments, but such details are for that purpose only, and it is to be understood that aspects or embodiments of the present disclosure are not limited to the disclosed embodiments, but on the contrary, are intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it is to be understood that the present disclosure contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.

Claims

**Claim 1** A drug delivery device comprising a fluid path including a reservoir, a pump downstream of the reservoir, and a fluid line downstream of the pump, the reservoir being configured to receive fluid and the pump being configured to deliver the fluid from the reservoir to the fluid line; a pressure sensor configured to measure pressure within the fluid path downstream of the pump; a microcontroller, receiving from the pressure sensor the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, determining whether the fluid delivered to the fluid line contains air bubbles based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, and a microcontroller programmed and / or configured to control an output device to provide an indication associated with the determination of whether the fluid delivered to the fluid line contains air bubbles. A drug delivery device comprising the same. **Claim 2** The pump includes a dosing chamber, the pump being configured to periodically (i) pump the reservoir using the dosing chamber that is in fluid communication with the reservoir and not in fluid communication with the fluid line, and (ii) fluidly connect the dosing chamber to the fluid line, and when the dosing chamber is fluidly connected to the fluid line, the fluid is delivered to the fluid line. The drug delivery device according to claim 1. **Claim 3** The microcontroller is receiving from the pressure sensor the pressure measured in the fluid path downstream of the pump before fluidly connecting the dosing chamber to the fluid line, further programmed and / or configured to determine a baseline pressure based on the pressure measured in the fluid path downstream of the pump before fluidly connecting the dosing chamber to the fluid line, and the microcontroller is programmed and / or configured to determine whether the fluid delivered to the fluid line contains air bubbles based on the pressure measured in the fluid path downstream of the pump and the baseline pressure when the fluid is delivered to the fluid line. The drug delivery device according to claim 2. **Claim 4** The microcontroller is comparing the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold pressure; determining that the fluid delivered to the fluid line contains bubbles in response to the pressure measured in the fluid path downstream of the pump when the fluid delivered to the fluid line meets the threshold pressure; The drug delivery device according to claim 1, which is programmed and / or configured to determine whether the fluid delivered to the fluid line contains bubbles. **Claim 5** The microcontroller determining a rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; comparing the rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold rate of change; determining that the fluid delivered to the fluid line contains bubbles in response to the rate of change associated with the pressure measured downstream of the fluid path of the pump when the fluid delivered to the fluid line meets the threshold rate of change; The drug delivery device according to claim 1, which is programmed and / or configured to determine whether the fluid delivered to the fluid line contains bubbles. **Claim 6** The microcontroller receiving a pressure associated with the fluid path upstream of the pump; Based on the pressure associated with the fluid path upstream of the pump, the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, and the dimensions of the fluid path, the volume of bubbles contained in the fluid delivered to the fluid line, the volume of the fluid delivered to the fluid line, or at least one of any combination thereof. The drug delivery device according to claim 1, which is programmed and / or configured to determine. **Claim 7** The microcontroller determining the pressure fluctuations over a period of time based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; comparing the variation in the pressure over the certain period to a threshold variation; determining that the fluid delivered to the fluid line contains air bubbles during the certain period in response to the variation in the pressure over the certain period that meets the threshold variation; the drug delivery device according to claim 1, which is programmed and / or configured to determine whether the fluid delivered to the fluid line contains air bubbles by the above.

8. The microcontroller is further programmed and / or configured to determine at least one of the volume of the air bubbles contained in the fluid delivered to the fluid line, the volume of the fluid delivered to the fluid line, or any combination thereof, based on the variation in the pressure over the certain period; the drug delivery device according to claim 7.

9. The pressure sensor includes at least one of an absolute pressure sensor, a differential pressure sensor, or any combination thereof; the drug delivery device according to claim 1.

10. The microcontroller is receiving, from the pressure sensor, the pressure measured in the fluid path downstream of the pump during priming of the pump; further programmed and / or configured to determine whether the pump is fully primed based on the pressure measured in the fluid path downstream of the pump during priming of the pump; the drug delivery device according to claim 1.

11. A pressure sensor-based air bubble detection method for a drug delivery device comprising a reservoir configured to receive a fluid, a pump downstream of the reservoir, and a fluid path including a fluid line downstream of the pump, comprising: delivering the fluid from the reservoir to the fluid line using the pump; measuring, using a pressure sensor, the pressure in the fluid path downstream of the pump when the fluid is delivered to the fluid line; receiving, using a microcontroller, the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; determining, using the microcontroller, whether the fluid delivered to the fluid line contains air bubbles based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; Controlling an output device using the microcontroller to provide an indication associated with determining whether the fluid delivered to the fluid line contains bubbles. **Claim 12** The pump includes a dosing chamber, and the pump periodically (i) pumps the reservoir using the dosing chamber that is in fluid communication with the reservoir and not in fluid communication with the fluid line, and (ii) fluidly connects the dosing chamber to the fluid line, and when the dosing chamber is fluidly connected to the fluid line, the fluid is delivered to the fluid line. The method according to claim 11. **Claim 13** Before fluidly connecting the dosing chamber to the fluid line, Measuring the pressure in the fluid path downstream of the pump using the pressure sensor; Before fluidly connecting the dosing chamber to the fluid line, determining a baseline pressure based on the pressure measured in the fluid path downstream of the pump, wherein whether the fluid delivered to the fluid line contains bubbles is determined based on the pressure measured in the fluid path downstream of the pump and the baseline pressure when the fluid is delivered to the fluid line. The determining further includes the method according to claim 12. **Claim 14** Determining whether the fluid delivered to the fluid line contains bubbles includes: Comparing the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold pressure; Determining that the fluid delivered to the fluid line contains bubbles in response to the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line that satisfies the threshold pressure. The method according to claim 11. **Claim 15** Determining whether the fluid delivered to the fluid line contains bubbles includes: Determining a rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; Comparing the rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line with a threshold rate of change; Determining that the fluid delivered to the fluid line contains bubbles in response to the rate of change associated with the pressure measured in the fluid path downstream of the pump when the fluid satisfies the threshold rate of change. The method according to claim 11 includes this step.

16. Receiving, using the microcontroller, a pressure associated with the fluid path upstream of the pump. Using the microcontroller to determine, based on the pressure associated with the fluid path upstream of the pump, at least one of the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line, the dimensions of the fluid path, the volume of the bubbles contained in the fluid delivered to the fluid line, the volume of the fluid delivered to the fluid line, or any combination thereof. The method according to claim 11 further includes this step.

17. Determining whether the fluid delivered to the fluid line contains bubbles includes: Determining the pressure fluctuation over a certain period based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line. Comparing the pressure fluctuation over the certain period with a threshold fluctuation. Determining that the fluid delivered to the fluid line contains bubbles during the certain period in response to the pressure fluctuation over the certain period satisfying the threshold fluctuation. The method according to claim 11 includes these steps.

18. Using the microcontroller to determine at least one of the volume of the bubbles contained in the fluid delivered to the fluid line, the volume of the fluid delivered to the fluid line, or any combination thereof, based on the pressure fluctuation over the certain period. The method according to claim 17 further includes this step.

19. Measuring, using the pressure sensor, another pressure in the fluid path downstream of the pump during priming of the pump. Receiving, using the microcontroller, from the pressure sensor, the another pressure measured in the fluid path downstream of the pump during priming of the pump. The method according to claim 11, further comprising determining whether the pump is fully primed based on the pressure measured downstream of the fluid path of the pump during the priming of the pump.

20. A computer program product for pressure sensor-based bubble detection for a drug delivery device comprising a microcontroller, a pressure sensor, and a reservoir configured to receive fluid, a pump downstream of the reservoir, and a fluid path including a fluid line downstream of the pump, wherein the computer program product, when executed by the microcontroller, causes the microcontroller to control the pump to deliver the fluid from the reservoir to the fluid line; control the pressure sensor to measure the pressure in the fluid path downstream of the pump when the fluid is delivered to the fluid line; receive from the pressure sensor the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; determine whether the fluid delivered to the fluid line contains bubbles based on the pressure measured in the fluid path downstream of the pump when the fluid is delivered to the fluid line; control an output device to provide a display associated with the determination of whether the fluid delivered to the fluid line contains bubbles, the computer program product comprising at least one non-transitory computer-readable medium including program instructions.

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