System and method for pressure control of drug delivery devices

Abstract

This invention provides a system and method for pressure control in drug delivery devices. [Solution] The drug delivery device includes a power supply, a reservoir configured to receive fluid, a fluid line communicating with the reservoir and the fluid, a pump configured to deliver fluid from the reservoir to the fluid line, and a power limiting subsystem configured to limit the power level supplied to the pump.

Description

Technical Field

[0001] The present disclosure relates to an apparatus for pressure management of a drug delivery device.

Background Art

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

[0003] Wearable medical devices, such as autoinjectors, have the advantage of providing therapy to patients away from clinical facilities and / or while individually worn under the patient's clothing. A wearable medical device is applied to the patient's skin and configured to automatically deliver a dose of a pharmaceutical composition after a predetermined time period, for example, after a 27-hour delay, after the wearable medical device has been applied to the patient's skin. After the device has delivered the pharmaceutical composition to the patient, the patient can subsequently remove and discard the device.

[0004] Under certain circumstances, due to the medium into which the liquid is injected, the flow of fluid out of the device is impaired, which can cause an increase in the pressure of the fluid line of the device. If the pressure exceeds a certain threshold, the integrity of the fluid path is impaired, leakage occurs within the device, and it may fail to deliver the full dose of the pharmaceutical product. Leakage of fluid within the device can also cause damage to the device and subsequent system malfunctions, as well as the possibility of contamination due to contact between the fluid and the device.

[0005] Human subcutaneous tissue is composed of various types of cells, extracellular matrix (ECM) components, microstructure, and the macroscopic arrangement of cells and ECM. These elements contribute to the tissue's mechanical properties. Tissue may also contain lymphatic systems and blood vessels and possesses inherent fluid absorption and retention properties. These properties can cause the degree of resistance to fluid injection at the injection site to vary between individuals, within the body, and over time. If the tissue's resistance is too high or its absorption rate too low for a given delivery flow rate from the device, pressure can build up and reach a valve threshold that can damage the fluid line or other components. [Overview of the Initiative]

[0006] In one aspect or embodiment, the drug delivery device includes a power supply, a reservoir configured to receive fluid, a fluid line communicating with the reservoir, a pump configured to deliver fluid from the reservoir to the fluid line, and a power limiting subsystem configured to limit the 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 drug delivery device may further include a microcontroller, and the power limiting subsystem may include the microcontroller configured to modulate the voltage supplied to the pump. The power limiting subsystem has an activated mode and an deactivated mode.

[0008] In further embodiments or models, a method for managing the pressure of a drug delivery device including a microcontroller, a reservoir, a pump, a fluid line, and a power supply includes: delivering fluid through the fluid line via the pump at a first power level; detecting the 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, wherein the second power level is lower than the first power level, until a predetermined condition is met; and resuming the delivery of the fluid through the fluid line at the first power level after the predetermined condition has been met.

[0009] The predetermined state 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 transistors such as bipolar transistors, MOSFET transistors, or CMOS transistors, op-amps, or other active circuits. The second power level may be provided by modulating the voltage supplied to the pump. The pressure in the fluid line may be detected by measuring the current in the drug delivery device while the pump is operating. Measuring the current in the drug delivery device may include determining a stroke current value by subtracting a reference current value from a peak current value during the pump's operating cycle. The power may be controlled by modulating or controlling the level of current, or by modulating or controlling the level of voltage.

[0010] In further embodiments or models, a computer program product for a method of pressure management of a drug delivery device including a microcontroller, a reservoir, a pump, a fluid line, and a power supply, the computer program product includes at least one non-transient computer-readable medium which, when executed by the microcontroller, causes the drug delivery device to: deliver fluid through the fluid line via the pump at a first power level; detect the 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, wherein the second power level is lower 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 drawing]

[0011] The aforementioned and other features and advantages of this disclosure, as well as the methods for achieving them, will become clearer, and the disclosure itself will be better understood by referring to the following description of embodiments of the disclosure in conjunction with the accompanying drawings. Here,

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

[0013] Corresponding reference numerals indicate corresponding parts through some of the figures. The examples described herein illustrate exemplary embodiments of the disclosure and should not be construed as limiting the scope of the disclosure. [Modes for carrying out the invention]

[0014] Spatial or directional terms such as "left," "right," "inside," "outside," "up," and "down" should not be considered limiting, as the present invention can envision a variety of alternative directions.

[0015] All numerical values ​​used herein and in the claims should be understood to be modified in all cases by the term “approximately.” “Approximately” means a range of plus or minus 10 percent of the stated value. Where used herein and in the claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly indicates otherwise. Terms such as “first,” “second,” etc., are not intended to refer to a particular order or sequence, but rather to different conditions, characteristics, or elements. “At least” means “greater than or equal to.”

[0016] Referring to Figures 1 to 3, the drug delivery device 10 includes a reservoir 12, a power supply 14, an insertion mechanism 16, a control electronic device 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 stimulant delivery device. The drug delivery device 10 is attached to the patient's skin and can operate 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 it can be filled with the pharmaceutical composition by the patient or a medical professional before use.

[0017] The drug delivery device 10 is configured to deliver a pharmaceutical composition, for example, a dose of any desired drug, to the patient's body by slow, controlled subcutaneous injection. The exemplary duration of delivery achieved by the drug delivery device 10 may range from about 5 minutes to about 60 minutes, but is not limited to this exemplary range. The volume of the exemplary pharmaceutical composition delivered by the drug delivery device 10 may range from about 0.1 milliliters to about 10 milliliters, but is not limited to this exemplary range. The volume of the pharmaceutical composition delivered to the patient may be adjusted.

[0018] Referring again to FIGS. 1 through 3, in one aspect or embodiment, the power source 14 is a direct current power source that includes one or more batteries. The control electronics 18 includes 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 fluid subsystem that includes a reservoir 12, a volume sensor 34 for the reservoir 12, a reservoir fill port 36, and a metering system 38 that includes a pump and valve actuator 40 and a pump and valve mechanism 42. The fluid 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 that is 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 stowed position that is fully within the device 10 to an extended position where the cannula 48 extends outside of the device 10. The drug delivery device 10 may operate in the same manner as discussed in Pizzochero et al.'s U.S. Patent No. 10,449,292, which is incorporated herein by reference.

[0019] Referring to FIGS. 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 a suction cycle and a dosing 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 via tests using a pressure sensor to measure the pressure in the fluid line 50.

[0020] Referring to FIGS. 6 to 9, in one aspect or embodiment, the drug 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 to 8, the power limiting subsystem 52 can be a current limiting subsystem 54. The current limiting subsystem 54 is configured to limit or set an upper limit on the current supplied to the pump and valve mechanism 42. The current limiting subsystem 54 can utilize a PNP transistor (FIG. 6) and / or an NPN transistor (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 the same period of time. The pulse width of the modulated signal can be smoothed by using a dedicated circuit such as a capacitor, or can be smoothed by the 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 power level supplied to the pump and valve mechanism 42 can be varied as needed. In one aspect or embodiment, the power limiting subsystem 52 has an activation mode in which the supplied power level is limited, and a deactivation mode in which the supplied power level is not limited. The activation mode and the deactivation mode can be provided via additional circuitry and / or by control via the microcontroller 24.

[0022] Referring to Figure 11, in one aspect or embodiment, the pressure control method 70 of the drug 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 the 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 until a predetermined condition is met, wherein the second power level is lower than the first power level 78, and resuming fluid delivery through the fluid line 50 at the first power level after the predetermined condition is met 80. 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 described above. The second power level may also be provided by modulating the voltage supplied to the pump, as described above.

[0023] Referring to Figures 10A to 10C, in one aspect or embodiment, the pressure in the fluid line 50 is detected by measuring the current of the drug delivery device 10 while the pump and valve mechanism 42 is operating. In one aspect or embodiment, the current is measured by measuring the voltage drop across a resistor. Measuring the current of the drug delivery device 10 involves subtracting a reference current value or baseline current value 84 from a peak current value 86 during the operating cycle of the pump and valve mechanism 42 to determine a stroke current value 88, although other suitable current sensing configurations may be utilized. The stroke current value 88 is used to estimate the downstream pressure in the fluid line 50 for a particular operating cycle of the pump and valve mechanism 42. For example, the stroke current value 88 can be adapted to various downstream pressure levels through testing or benchmarking so 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 illustrative purposes based on embodiments considered to be the most practical and preferred embodiments at present, such details are for that purpose only, and it should be understood that the present invention is not limited to the disclosed embodiments, but rather intended to cover modified and equivalent components within the spirit and scope of the appended claims. For example, it should be understood that, to the extent possible, the present invention is intended to allow one or more features of any embodiment to be combined with one or more features of any other embodiment.

Claims

1. Power supply and A reservoir configured to receive fluid, A fluid line that is 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 the power supplied to the pump, having a first power level and a second power level, wherein the first power level is higher than the second power level, and the pump delivers fluid through the fluid line via the pump at the first power level until a high-pressure threshold level is reached, and thereafter delivers the fluid through the fluid line at the second power level, A drug delivery device equipped with the following features.

2. The power limiting subsystem comprises a current limiting subsystem. The drug delivery device according to claim 1.

3. The current limiting subsystem comprises a transistor or an op-amp. The drug delivery device according to claim 2.

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

5. The aforementioned power is controlled by modulating or controlling the level of current. The drug delivery device according to claim 4.

6. The power is controlled by modulating or controlling the voltage level. The drug delivery device according to claim 4.

7. The power limiting subsystem has an activated mode and an inactivated mode. A drug delivery device according to any one of claims 1 to 6.

8. A method for controlling the pressure of a drug delivery device according to any one of claims 1 to 7, Delivering fluid through the fluid line via the pump at a first power level, To detect the 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 until a predetermined condition is met, wherein the second power level is lower than the first power level. After the predetermined conditions are met, the delivery of the fluid through the fluid line is resumed at the first power level. A method that includes this.

9. The predetermined state includes a predetermined pressure level in the fluid line. The method according to claim 8.

10. The second power level is provided via a current limiting subsystem. The method according to claim 8.

11. The current limiting subsystem comprises a transistor or an op-amp. The method according to claim 10.

12. The second power level is provided by modulating the voltage supplied to the pump. The method according to claim 8.

13. The pressure in the fluid line is detected by measuring the current of the drug delivery device while the pump is operating. The method according to any one of claims 8 to 12.

14. Measuring the current of the drug delivery device includes determining the stroke current value by subtracting a reference current value from the peak current value during the operating cycle of the pump. The method according to claim 13.

15. A computer program for a method of pressure management of a drug delivery device according to any one of claims 1 to 7, wherein when executed by a microcontroller, the drug delivery device is configured to: Delivering fluid through the fluid line via the pump at a first power level, To detect the 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 until a predetermined condition is met, wherein the second power level is lower than the first power level. After the predetermined conditions are met, the delivery of the fluid through the fluid line is resumed at the first power level. A computer program that includes program instructions that cause something to happen.

16. The predetermined state includes a predetermined pressure level in the fluid line. The computer program according to claim 15.

17. When the computer program is executed by the microcontroller, the microcontroller will: The voltage supplied to the pump is modulated to provide the second power level. Further including program instructions that cause the following: The computer program according to claim 15.

18. When the computer program is executed by the microcontroller, it is directed to the drug delivery device. The current of the drug delivery device while the pump is operating is measured to detect the pressure in the fluid line. Further including program instructions that cause the following: The computer program according to claim 15.

19. Measuring the current of the drug delivery device includes determining the stroke current value by subtracting a reference current value from the peak current value during the operating cycle of the pump. The computer program according to claim 18.

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