Systems and methods for pressure management in medication delivery devices

Abstract

The drug delivery device includes a power source, a reservoir configured to receive a fluid, a fluid line in fluid communication with the reservoir, a pump configured to deliver the fluid from the reservoir to the fluid line, and a power limiting subsystem configured to limit the level of power supplied to the pump.

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus for pressure management in a medication delivery device. [Background technology]

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 114,905, entitled "System and Method for Pressure Management for a Drug Delivery Device," filed November 17, 2020, the entire disclosure of which is incorporated herein by reference.

[0003] Wearable medical devices, such as auto-injectors, have the advantage of providing therapy to patients at locations away from clinical facilities and / or while being worn individually under the patient's clothing. The wearable medical device can be configured to be applied to the patient's skin and to automatically deliver a dose of a pharmaceutical composition within a predetermined time period, e.g., after a 27-hour delay, after application of the wearable medical device to the patient's skin. After the device delivers the pharmaceutical composition to the patient, the patient can subsequently remove and discard the device.

[0004] Under certain circumstances, the medium in which the liquid is injected can impair fluid flow exiting the device, causing an increase in pressure in the device's fluid lines. If the pressure exceeds a certain threshold, the integrity of the fluid pathway can be compromised, causing leaks within the device and a failure to deliver the full dose of medication. Fluid leaks within the device can also cause damage to the device and subsequent system failure, as well as potential contamination concerns from fluid contact with the device.

[0005] Human subcutaneous tissue is composed of various cell types, extracellular matrix (ECM) components, microstructure, and the macroscopic arrangement of cells and ECM. These elements contribute to the tissue's mechanical properties. Tissues may also contain lymphatic systems and blood vessels, which have inherent fluid absorption and retention properties. These properties can vary across individuals, locations within the body, and over time, creating varying degrees of resistance to fluid infusion at the injection site. If tissue resistance is too high or absorption rate is too low for a given delivery flow rate from the device, pressure can build up and reach a valve beyond a threshold where fluid lines and other components may be compromised. Summary of the Invention

[0006] In one aspect or embodiment, a drug delivery device includes a power source, a reservoir configured to receive a fluid, a fluid line in fluid communication with the reservoir, a pump configured to deliver fluid from the reservoir to the fluid line, and a power limiting subsystem configured to limit a power level supplied to the pump.

[0007] The power limiting subsystem may be a current limiting subsystem. The current limiting subsystem may include a PNP transistor or an NPN transistor. The medication delivery device may further include a microcontroller, and the power limiting subsystem may include the microcontroller configured to modulate a voltage supplied to the pump. The power limiting subsystem has an active mode and an inactive mode.

[0008] In a further aspect or embodiment, a method of pressure management in a medication delivery device including a microcontroller, a reservoir, a pump, a fluid line, and a power source includes delivering fluid through the fluid line via the pump at a first power level, detecting pressure in the fluid line, determining whether the pressure in the fluid line exceeds a high pressure threshold level, delivering fluid through the fluid line via the pump at a second power level lower than the first power level until a predetermined condition is met, the second power level being lower than the first power level, and resuming delivery of the fluid through the fluid line at the first power level after the predetermined condition is met.

[0009] The predetermined condition may be a predetermined pressure level in the fluid line. The second power level may be provided via a current limiting subsystem. The current limiting subsystem may include a transistor, such as a bipolar transistor, a MOSFET transistor, or a CMOS transistor, an op-amp, or other active circuitry. The second power level may be provided by modulating a voltage supplied to the pump. The pressure in the fluid line may be detected by measuring a current in the drug delivery device during operation of the pump. Measuring the current in the drug delivery device may include subtracting a reference current value from a peak current value during an operation cycle of the pump to determine a stroke current value. The power may be controlled by modulating or controlling a level of current or by modulating or controlling a level of voltage.

[0010] In a further aspect or embodiment, a computer program product for a method of pressure management of a medication delivery device including a microcontroller, a reservoir, a pump, a fluid line, and a power source, the computer program product including at least one non-transitory computer-readable medium including program instructions that, when executed by the microcontroller, cause the medication delivery device to: deliver fluid through the fluid line via the pump at a first power level; detect pressure in the fluid line; determine whether the pressure in the fluid line exceeds a high-pressure threshold level; deliver fluid through the fluid line via the pump at a second power level less than the first power level until a predetermined condition is met; and resume delivery of the fluid through the fluid line at the first power level after the predetermined condition is met. [Brief explanation of the drawings]

[0011] The above and other features and advantages of the present disclosure, and the manner in which they are achieved, will become more apparent, and the disclosure itself will be better understood, by reference to the following description of the embodiments of the disclosure taken in conjunction with the accompanying drawings, in which:

[0012] [Figure 1] FIG. 1 is a perspective view of a drug delivery device according to a first aspect or embodiment of the present application. [Figure 2] FIG. 2 is a perspective view of the medication delivery device of FIG. 1 with the top cover removed. [Figure 3] FIG. 3 is a schematic diagram of the drug delivery device of FIG. [Figure 4] FIG. 4 is a graph of current versus time for the drug delivery device of FIG. 1 showing a 0 psi pressure condition according to a first aspect or embodiment of the present application. [Figure 5] FIG. 5 is a graph of current versus time for the drug delivery device of FIG. 1 showing a 40 psi pressure condition according to a first aspect or embodiment of the present application. [Figure 6]FIG. 6 is a schematic diagram of a current limiting circuit according to a first aspect or embodiment of the present application. [Figure 7] FIG. 7 is a schematic diagram of a current limiting circuit according to a second aspect or embodiment of the present application. [Figure 8] FIG. 8 is a schematic diagram of a current limiting circuit according to a third aspect or embodiment of the present application. [Figure 9] FIG. 9 is a schematic diagram of a method for modulating power according to a further aspect or embodiment of the present application. [Figure 10A] FIG. 10A is a graph of current versus time for the drug delivery device of FIG. 1 illustrating a method of determining fluid pathway pressure according to a first aspect or embodiment of the present application. [Figure 10B] FIG. 10B is an enlarged graph of region 10B shown in FIG. 10A. [Figure 10C] FIG. 10C is an enlarged graph of region 10C shown in FIG. 10B. [Figure 11] FIG. 11 is a schematic illustration of a method for power management of a medication delivery device according to a first aspect or embodiment of the present application.

[0013] Corresponding reference characters indicate corresponding parts throughout the several views. The illustrations set forth herein illustrate exemplary embodiments of the present disclosure, and such illustrations are not to be construed as limiting the scope of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Spatial or directional terms such as "left," "right," "inside," "outside," "above," and "below" should not be considered limiting as the present invention can assume various alternative orientations.

[0015] All numerical values ​​used in the specification and claims should be understood to be modified in all instances by the term "about." "About" means a range of plus or minus ten percent of the stated value. As used in the specification and claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. The terms "first," "second," etc. are not intended to refer to a particular order or sequence, but instead refer to different conditions, characteristics, or elements. "At least" means "greater than or equal to."

[0016] 1-3 , a drug delivery device 10 includes a reservoir 12, a power source 14, an insertion mechanism 16, control electronics 18, a cover 20, and a base 22. In one aspect or embodiment, the drug delivery device 10 is a wearable auto-injector, such as an insulin or bone marrow stimulating agent delivery device. The drug delivery device 10 can be attached to a patient's skin and operated to inject a pharmaceutical composition from the reservoir 12 into the patient. The drug delivery device 10 can be pre-filled with the pharmaceutical composition or can be filled with the pharmaceutical composition by the patient or a medical professional prior to use.

[0017] The drug delivery device 10 is configured to deliver a pharmaceutical composition, e.g., a dose of any desired drug, to a patient's body by subcutaneous injection at a slow, controlled injection rate. Exemplary time durations for delivery achieved by the drug delivery device 10 can range from about 5 minutes to about 60 minutes, but are not limited to this exemplary range. Exemplary volumes of pharmaceutical compositions delivered by the drug delivery device 10 can range from about 0.1 milliliters to about 10 milliliters, but are not limited to this exemplary range. The volume of pharmaceutical composition delivered to a patient can be adjusted.

[0018] 1-3 , in one aspect or embodiment, the power supply 14 is a DC power supply including one or more batteries. The control electronics 18 include a microcontroller 24, sensing electronics 26, a pump and valve controller 28, sensing electronics 30, and deployment electronics 32, which control the operation of the drug delivery device 10. The drug delivery device 10 includes a fluidic subsystem including the reservoir 12, a capacitance sensor 34 for the reservoir 12, a reservoir fill port 36, and a measurement system 38 including a pump and valve actuator 40 and a pump and valve mechanism 42. The fluidic subsystem may further include an occlusion sensor 44, a deployment actuator 46, a cannula 48 for insertion into the patient's skin, and a fluid line 50 in fluid communication with the reservoir 12 and the cannula 48. In one aspect or embodiment, the insertion mechanism 16 is configured to move the cannula 48 from a retracted position, where the cannula 48 is fully positioned within the device 10, to an extended position, where the cannula 48 extends outside the device 10. The drug delivery device 10 may operate in the same manner as discussed in U.S. Patent No. 10,449,292 to Pizzochero et al., which is incorporated herein by reference.

[0019] 4 and 5, the relationship between the pressure in the fluid line 50 and the current required to push the pump and valve mechanism 42 forward is shown. The pump and valve mechanism 42 has an aspiration cycle and a dispense cycle as shown in FIGS. 4 and 5. As shown in FIG. 4, at a current of 1.95 mA, the pressure in the fluid line 50 can be estimated to be approximately 0 psi. As shown in FIG. 5, at a current of 7.61 mA, the pressure in the fluid line 50 can be estimated to be approximately 40 psi. The correlation between the current and the pressure in the fluid line 50 can be determined through testing using a pressure sensor to measure the pressure in the fluid line 50.

[0020] 6-9 , in one aspect or embodiment, the medication delivery device 10 includes a power limiting subsystem 52 configured to limit the power level supplied to the pump and valve mechanism 42. As shown in FIGS. 6-8 , the power limiting subsystem 52 may be a current limiting subsystem 54. The current limiting subsystem 54 is configured to limit or cap the current supplied to the pump and valve mechanism 42. The current limiting subsystem 54 may utilize PNP transistors ( FIG. 6 ) and / or NPN transistors ( FIGS. 7 and 8 ). In a further aspect or embodiment, the power limiting subsystem 52 is provided by the microcontroller 24 modulating the voltage supplied to the pump and valve mechanism 42. As shown in FIG. 9 , by using pulse width modulation, the power supplied to the pump and valve mechanism 42 can be modulated. For example, using narrow pulses over a period of time will result in a lower average voltage than using wider pulses over a period of time. The pulse width modulated signal can be smoothed by using a dedicated circuit, such as a capacitor, or may be smoothed by a load formed by the actuator itself.

[0021] In one aspect or embodiment, the power limiting subsystem 52 is configured to be adjustable so that the level of power delivered to the pump and valve mechanism 42 can be varied as needed. In one aspect or embodiment, the power limiting subsystem 52 has an active mode in which the level of power delivered is limited, and a deactivated mode in which the level of power delivered is not limited. The active and deactivated modes may be provided via additional circuitry and / or by control via the microcontroller 24.

[0022] 11 , in one aspect or embodiment, a method 70 of pressure management for a medication delivery device 10 includes delivering fluid through a fluid line 50 via a pump and valve mechanism 42 at a first power level 72, detecting pressure in the fluid line 50 74, determining whether the pressure in the fluid line 50 exceeds a high-pressure threshold level 76, delivering fluid through the fluid line 50 via the pump and valve mechanism 42 at a second power level 78, the second power level being lower than the first power level, and resuming delivery of fluid through the fluid line 50 at the first power level 80 after the predetermined condition is met. In one aspect or embodiment, the predetermined condition is a predetermined pressure level in the fluid line. The second power level may be provided via the current limiting subsystem 54, as previously described. The second power level may also be provided by modulating the voltage supplied to the pump, as previously described.

[0023] 10A-10C , in one aspect or embodiment, the pressure in the fluid line 50 is detected by measuring the current through the drug delivery device 10 during actuation of the pump and valve mechanism 42. In one aspect or embodiment, the current is measured by measuring the voltage drop across a resistor. Measuring the current through the drug delivery device 10 includes subtracting a reference or baseline current value 84 from a peak current value 86 during an actuation cycle of the pump and valve mechanism 42 to determine a stroke current value 88, although other suitable current detection configurations may be utilized. The stroke current value 88 is utilized to estimate the downstream pressure in the fluid line 50 for a particular actuation cycle of the pump and valve mechanism 42. For example, the stroke current value 88 may be associated with various downstream pressure levels through testing or benchmarking such that the stroke current value 88 can be used to accurately estimate the pressure level in the fluid line 50.

[0024] While the present invention has been described in detail for purposes of illustration based on what are presently considered to be the most practical and preferred embodiments, it should be understood that such detail is for that purpose only and that the invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover modifications and equivalent arrangements within the spirit and scope of the appended claims. For example, it should be understood that the present invention 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

1. Power supply and a reservoir configured to receive a fluid; a fluid line in fluid communication with the reservoir; a pump configured to deliver fluid from the reservoir to the fluid line; a power limiting subsystem configured to limit power supplied to the pump based on pressure in the fluid line detected by determining a stroke current value equal to a peak current value minus a reference current value during an operating cycle of the pump; and A drug delivery device comprising:

2. the power limiting subsystem comprises a current limiting subsystem. The drug delivery device of claim 1 .

3. the current limiting subsystem comprises a transistor or an op-amp; The drug delivery device of claim 2 .

4. and a microcontroller, wherein the power limiting subsystem comprises the microcontroller configured to modulate the power supplied to the pump. The drug delivery device of claim 1 .

5. The power is controlled by modulating or controlling the level of current.

5. The drug delivery device of claim 4.

6. The power is controlled by modulating or controlling the level of voltage.

5. The drug delivery device of claim 4.

7. the power limiting subsystem has an active mode and an inactive mode; The drug delivery device according to any one of claims 1 to 6.

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