CLUTCH DEVICE FOR COMPACT POSITIVE DISPLACEMENT PUMP OF A WEARABLE DRUG DELIVERY DEVICE

Embodiments of the present disclosure relate to techniques, processes, devices or systems for pump devices. In one approach, a wearable drug delivery device, may include a reservoir configured to store a fluid, the reservoir comprising a housing including an outer wall defining an interior chamber, and a drive mechanism for driving the fluid from the reservoir. The drive mechanism may include a plunger received in the interior chamber of the reservoir, a leadscrew extending from the plunger, and a clutch mechanism threadably engaged with the leadscrew, wherein the clutch mechanism is configured to allow the leadscrew to pass through the clutch mechanism when disengaged and is configured to grip the leadscrew when engaged such that the clutch mechanism rotates to advance the leadscrew and the plunger into the reservoir.

TECHNICAL FIELD

The disclosed embodiments generally relate to medication delivery. More particularly, the disclosed embodiments relate to techniques, processes, systems, and dispensing devices for delivering a fluid medicament in a space-efficient manner.

BACKGROUND

Fluid delivery devices have numerous uses such as delivering a fluid medicament to a patient subcutaneously. In a patient with diabetes mellitus, for example, ambulatory infusion pumps have been used to deliver insulin to the patient. These infusion pumps have the ability to offer sophisticated fluid delivery profiles including variable basal rates and bolus requirements. The ability to carefully control drug delivery can result in better efficacy of the drug and therapy and less toxicity to the patient.

Some existing infusion pumps include a reservoir to contain the fluid medicament and use electromechanical pumping or metering technology to deliver the fluid medicament via tubing to a needle and/or soft cannula that is inserted subcutaneously into the patient. Some infusion pumps have been designed to be relatively small, low cost, light-weight, and easy-to-use. These pumps include insertion mechanisms for delivering the needle and/or soft cannula into a patient. The design of the insertion mechanism may be improved, however, to reduce the size of the pump, to improve the comfort to the user, and/or to reduce the number of components of the pump.

Accordingly, there is a need for a simplified system for accurately expelling fluid medicament from a reservoir, which also reduces overall drug delivery device size.

SUMMARY

In some approaches, a wearable drug delivery device may include a reservoir configured to store a fluid, the reservoir comprising a housing including an outer wall defining an interior chamber, and a drive mechanism for driving the fluid from the reservoir. The drive mechanism may include a plunger received in the interior chamber of the reservoir, a leadscrew extending from the plunger, and a clutch mechanism threadably engaged with the leadscrew, wherein the clutch mechanism is configured to allow the leadscrew to pass through the clutch mechanism when disengaged and is configured to grip the leadscrew when engaged such that the clutch mechanism rotates to advance the leadscrew and the plunger in the reservoir.

In some approaches, a wearable drug delivery device may include a reservoir configured to store a liquid drug, the reservoir comprising a housing including an outer wall defining an interior chamber, and a drive mechanism for driving the liquid drug from the reservoir. The drive mechanism may include a plunger received in the interior chamber of the reservoir, a leadscrew extending from the plunger, and a drive wheel operable with a clutch mechanism to rotate a clutch spring to advance the leadscrew, wherein the clutch mechanism is configured to allow the leadscrew to pass through the clutch spring when in a disengaged position and is configured to grip the leadscrew when in an engaged position such that the drive wheel rotates the clutch spring to advance the leadscrew and the plunger into the reservoir.

In some approaches, a method may include providing a reservoir configured to store a liquid drug, the reservoir comprising a housing including an outer wall defining an interior chamber, and providing a drive mechanism for driving the liquid drug from the reservoir. The drive mechanism may include a plunger received in the interior chamber of the reservoir, a leadscrew extending from the plunger, and a drive wheel operable with a clutch mechanism. The method may further include rotating a clutch spring of the clutch mechanism to advance the leadscrew, wherein the clutch mechanism is configured to allow the leadscrew to pass through the clutch spring when in a disengaged position and configured to grip the leadscrew when in an engaged position.

The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. The drawings are intended to depict exemplary embodiments of the disclosure, and therefore are not be considered as limiting in scope. Furthermore, certain elements in some of the figures may be omitted, or illustrated not-to-scale, for illustrative clarity. Still furthermore, for clarity, some reference numbers may be omitted in certain drawings.

DETAILED DESCRIPTION

Systems, devices, and methods in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, where one or more embodiments are shown. The systems, devices, and methods may be embodied in many different forms and are not to be construed as being limited to the embodiments set forth herein. Instead, these embodiments are provided so the disclosure will be thorough and complete, and will fully convey the scope of methods and devices to those skilled in the art. Each of the systems, devices, and methods disclosed herein provides one or more advantages over conventional systems, components, and methods.

One approach for actuating a fluidic pump is to employ a linear motion generated by a leadscrew and a spring/clutch mechanism. This mechanism converts the rotational motion of an actuator, which may be one or more SMA wires, solenoids, motors, etc., to an accurate linear motion. As an example, in a positive displacement fluidic pump, the linear motion generated by the leadscrew is transferred to a plunger within a reservoir and results in an accurate and controlled dispensing of the fluid from the reservoir. During the filling process, the plunger remains disengaged from the leadscrew and the spring/clutch mechanism so the fluid may move the plunger freely to any position based the filled volume. When the user is done filling, the spring/clutch mechanism connects with the leadscrew and the plunger, thus enabling the device to dispense the fluid out of the reservoir.

In some embodiments, the spring is initially in the loaded configuration with an inside diameter (ID) larger than the outside diameter (OD) of the leadscrew, thus allowing the spring and the leadscrew to move freely relative to one another as the user fills the pod. When desired, the clutch mechanism may release the spring, which causes a reduction in the ID of the coil and direct engagement of the spring with the leadscrew. In some embodiments, the spring engages with threading along an exterior of the leadscrew. Rotation of the leadscrew therefore results in the linear motion of the spring and the plunger, enabling the pod to accurately dispense the fluid.

In various embodiments, the wearable drug delivery device described herein may include an analyte sensor, such as a blood glucose sensor, and the cannula or microneedle array may be operable in allowing the device to measure an analyte level in a user of the device.

FIG.1illustrates a simplified block diagram of an example system (hereinafter “system”)100. The system100may be a wearable or on-body drug delivery device and/or an analyte sensor attached to the skin of a patient103. The system100may include a controller102, a pump mechanism104(hereinafter “pump104”), and a sensor108within one or more housings. The sensor108may be a glucose or other analyte monitor such as, for example, a continuous glucose monitor, and may be incorporated into the wearable device. The sensor108may, for example, be operable to measure blood glucose (BG) values of a user to generate a measured BG level signal112. The controller102, the pump104, and the sensor108may be communicatively coupled to one another via a wired or wireless communication path. For example, each of the controller102, the pump104and the sensor108may be equipped with a wireless radio frequency transceiver operable to communicate via one or more communication protocols, such as Bluetooth®, or the like. The system100may also include a delivery pump device (hereinafter “device”)105, which includes a drive mechanism106coupled to a reservoir126for driving a liquid drug125therefrom. As will be described in greater detail herein, the drive mechanism106may include a piston head or plunger134disposed within an interior chamber of a housing139of the reservoir126, and a leadscrew135couplable with a clutch spring136. The system100may include additional components which are not shown or described for the sake of brevity.

The controller102may receive a desired BG level signal, which may be a first signal, indicating a desired BG level or range for the patient103. The desired BG level signal may be stored in memory of a controller109on device105, received from a user interface to the controller102, or another device, or by an algorithm within controller109(or controller102) that automatically determines an appropriate BG level or target for the patient103. The sensor108may be coupled to the patient103and operable to measure an approximate value of a BG level of the user. In response to the measured BG level or value, the sensor108may generate a signal indicating the measured BG value. As shown, the controller102may also receive from the sensor108via a communication path, the measured BG level signal112, which may be a second signal.

Based on the desired BG level signal and the measured BG level signal112, the controller102or controller109may generate one or more control signals for directing operation of the pump104. For example, one control signal119from the controller102or controller109may cause the pump104to turn on, or activate one or more power elements123operably connected with the device105. The specified amount of the liquid drug125may be determined as an appropriate amount of insulin to drive the measured BG level of the user to the desired BG level. Based on operation of the pump104, as determined by the control signal119, the patient103may receive the liquid drug from the reservoir126. The system100may operate as a closed-loop system, an open-loop system, or as a hybrid system. In an exemplary closed-loop system, the controller109may direct operation of the device105without input from the controller102, and may receive BG level signal112from the sensor108. The sensor108may be housed within the device105or may be housed in a separate device and communicate wirelessly directly with the device105.

As further shown, the system100may include a needle deployment component128that is in communication with the controller102or the controller109. The needle deployment component128may include a needle/cannula129deployable into the patient103and may have one or more holes at a distal end thereof. The needle deployment component128may be housed within the device105or a separate component connectable to the device105. The device105may be connected to the needle/cannula129by a fluid path component130. The fluid path component130may be of any size and shape and may be made from any material. The fluid path component130can allow fluid, such as the liquid drug125in the reservoir126, to be transferred to the needle/cannula129.

The controller102/109may be implemented in hardware, software, or any combination thereof. The controller102/109may, for example, be a processor, a logic circuit or a microcontroller coupled to a memory. The controller102/109may maintain a date and time as well as other functions (e.g., calculations or the like) performed by processors. The controller102/109may be operable to execute an artificial pancreas (AP) algorithm stored in memory (not shown) that enables the controller102/109to direct operation of the pump104. For example, the controller102/109may be operable to receive an input from the sensor108, wherein the input indicates an automated insulin delivery (AID) application setting. Based on the AID application setting, the controller102/109may modify the behavior of the pump104and resulting amount of the liquid drug125to be delivered to the patient103via the device105.

In some embodiments, the sensor108may be, for example, a continuous glucose monitor (CGM). The sensor108may be physically separate from the pump104, or may be an integrated component within a same housing thereof or otherwise physically integrated. The sensor108may provide the controller102with data indicative of measured or detected blood glucose levels of the user.

The power element123may be a battery, a piezoelectric device, or the like, for supplying electrical power to the device105. In other embodiments, the power element123, or an additional power source (not shown), may also supply power to other components of the pump104, such as the controller102, memory, the sensor108, and/or the needle deployment component128.

In an example, the sensor108may be a device communicatively coupled to the controller102and may be operable to measure a blood glucose value at a predetermined time interval, such as approximately every 5 minutes, 10 minutes, or the like. The sensor108may provide a number of blood glucose measurement values to the AP application.

In some embodiments, the pump104, when operating in a normal mode of operation, provides insulin stored in the reservoir126to the patient103based on information (e.g., blood glucose measurement values, target blood glucose values, insulin on board, prior insulin deliveries, time of day, day of the week, inputs from an inertial measurement unit, global positioning system-enabled devices, Wi-Fi-enabled devices, or the like) provided by the sensor108or other functional elements of the pump104. For example, the pump104may contain analog and/or digital circuitry that may be implemented as the controller102/109for controlling the delivery of the drug or therapeutic agent. The circuitry used to implement the controller102/109may include discrete, specialized logic and/or components, an application-specific integrated circuit, a microcontroller or processor that executes software instructions, firmware, programming instructions or programming code enabling, for example, an AP application stored in memory, or any combination thereof. For example, the controller102/109may execute a control algorithm and other programming code that may make the controller102/109operable to cause the pump to deliver doses of the drug or therapeutic agent to a user at predetermined intervals or as needed to bring blood glucose measurement values to a target blood glucose value. The size and/or timing of the doses may be at least partially pre-programmed, for example, into the AP application by the patient103or by a third party (such as a health care provider, a parent or guardian, a manufacturer of the wearable drug delivery device, or the like) using a wired or wireless link.

Although not shown, in some embodiments, the sensor108may include a processor, memory, a sensing or measuring device, and a communication device. The memory may store an instance of an AP application as well as other programming code and be operable to store data related to the AP application.

In various embodiments, the sensing/measuring device of the sensor108may include one or more sensing elements, such as a blood glucose measurement element, a blood pressure monitor, a heart rate monitor, a blood oxygen sensor element, or the like. The sensor processor may include discrete, specialized logic and/or components, an application-specific integrated circuit, a microcontroller or processor that executes software instructions, firmware, programming instructions stored in memory, or any combination thereof.

Turning now toFIG.2, the drive mechanism106according to embodiments of the present disclosure will be described in greater detail. As shown, the drive mechanism106may be positioned within an interior chamber150of the housing139of the reservoir126. The housing139may include an outer wall defining the interior chamber150, wherein the outer wall includes an exterior surface opposite an interior surface. Although non-limiting, the housing139may be a circular or an oval-shaped cylinder including a first end157opposite a second end158.

As further shown, the drive mechanism106may include the plunger134disposed within the interior chamber150of the housing139. In some embodiments, the plunger134may include a sealing ring162(e.g., O-ring) extending circumferentially about an outer surface163of the plunger134. The sealing ring162may be in contact with the interior surface of the outer wall of the housing139to create a liquid-tight seal therebetween. The leadscrew135may be coupled to the plunger134, or may be an inseparable, insert-molded assembly.

Some embodiments of the drive mechanism106may include a clutch mechanism170to facilitate filling and dispensing of fluid within the reservoir126and engagement of the drive mechanism106for driving fluid out of the reservoir126. The clutch spring136may engage the leadscrew135and may be driven by a drive wheel156via the clutch mechanism170.

When the reservoir126is empty or in a pre-filled state, as shown inFIG.2, the plunger134is positioned at the second end158end of the reservoir126such that the plunger134is extended and the clutch mechanism170is disengaged. In certain embodiments, the reservoir126may then be filled with fluid medicament, such as insulin, by opening an inlet port to the reservoir126and pumping in the insulin under sufficient hydraulic pressure to retract the plunger134within the reservoir126toward the first end157. Thereafter, the inlet port may be closed. When the reservoir126is filled and the plunger134has moved to or toward the first end157of the reservoir126, the clutch mechanism170remains disengaged to allow the leadscrew135to pass through the clutch spring and the into an elongated cylindrical bore (along the drive axis) of a hub of the drive wheel156. The clutch mechanism170may then be engaged such that rotation of the drive wheel156causes the clutch mechanism170to rotate the clutch spring136, which causes the leadscrew135to advance the plunger134into the reservoir126to deliver the fluid therefrom. In alternative embodiments, the reservoir126may be filled when the plunger134is already retracted. In the illustrated embodiment, the drive wheel156may include one or more ratchets186that are engaged by an actuator to incrementally drive the drive wheel156and advance the plunger134across the reservoir126.

In some embodiments, as illustrated inFIGS.3A-3B, the clutch spring136of the clutch mechanism170may be a helical torsion spring located in a counterbore172(FIG.3B) at one end of the drive wheel156. The ID of the clutch spring136may be larger than the outside diameter of the leadscrew135when the clutch spring136is loaded, thereby disengaging the clutch spring136from the leadscrew135and allowing the leadscrew135to pass through a center aperture of the clutch spring136and into an elongated bore174of the drive wheel156. Alternatively, the ID of the clutch spring136may be smaller than the outside diameter of the leadscrew135when the clutch spring136is unloaded, thereby engaging or gripping the leadscrew135and allowing the drive wheel156to rotate the leadscrew135. In some embodiments, the clutch spring136engages external threading138of the leadscrew135.

In the illustrated embodiment, prior to filing the reservoir126, the clutch spring136may be held in the loaded, disengaged position by a spring latch164engaged with the drive wheel156. After the reservoir126has been filled, the clutch spring136may be engaged by rotating the drive wheel156until the spring latch164releases the clutch spring136, allowing the clutch spring136to unload and grip leadscrew135. The fluid may then be dispensed from the reservoir126with continued rotation of the drive wheel156.

In some embodiments, the spring latch164may be biased by the clutch spring136such that as the drive wheel156rotates, the spring latch164moves rotationally against a surface of a reservoir cap175until the clutch spring136deflects the spring latch164into a window176in the reservoir cap175. When the spring latch164moves into the window176, a first end178(FIG.3A) of the clutch spring136held by the spring latch164is released, thus engaging the clutch mechanism170. When the clutch spring136is engaged, the drive wheel156contacts a second end179of the clutch spring136to create a thrust on the clutch spring136that causes the clutch spring136to rotate the leadscrew135.

Turning now toFIGS.4A-4B, operation of the clutch spring136and leadscrew135according to another embodiment will be described. In this embodiment, the clutch spring136may be coupled to, or extend along, an interior surface of a slider184. The slider184may be a cylinder coupled to the plunger (not shown). This embodiment may reduce the required length of the overall drive system (and the clutch mechanism in particular) to approximately half, thus enabling the overall size of the drive mechanism to be reduced. In addition, no tube nut is required in this drive mechanism, which reduces the overall part count and complexity of the system. In other prior drive mechanisms, a tube nut was positioned between a spring and the leadscrew and was used to convert the rotational motion of a rotating drive member to translational motion of the lead screw. Such tube nuts typically extended along much of the length of the leadscrew, thereby increasing the required length of the clutch mechanism and overall drive system to approximately 2× the length of the leadscrew, and also allowed the drive member to rotate the leadscrew via two components, i.e., a spring and the tube nut. In the advances disclosed herein, the tube nut is removed and the spring is modified to allow the spring to engage directly with the leadscrew. As explained above, this reduces the required length of the overall drive system, overcoming the “2× length” problem, while also reducing the number of required parts for the drive system and clutch mechanism.

As described above, the clutch spring136may initially be in the loaded configuration with an ID larger than the OD of the leadscrew135, allowing the slider184to move freely along the leadscrew135as the reservoir is being filled. When released, the clutch spring136causes a reduction in the ID of the clutch spring136and engagement of the clutch spring136and the slider184with the leadscrew135. After release of the clutch spring136, the slider184functions similar to a drive nut, while the clutch spring136acts as internal threading engaged with and/or following the threads on the OD of the leadscrew135. Hence, rotation of the clutch spring136results in the linear motion of the leadscrew135and the plunger, enabling the drive mechanism to accurately dispense fluid from the reservoir.

FIGS.5A-5Cdemonstrate various non-limiting examples of the clutch spring136described herein. As shown, each clutch spring136may include a helically shaped main body189between the first end178and the second end179. The main body189may define a center aperture191operable to receive the leadscrew therein. The main body189may include a plurality of loops or convolutions192operable to engage indentations of the external threading of the leadscrew. Although non-limiting, the clutch spring136may have a circular cross-section, an oval or elliptical cross-section (FIG.5A), a square or diamond profile (FIG.5B), or a triangular profile (FIG.5C). The non-circular profiles can be used to create a complimentary, mating thread-form geometry with the external threading of the lead screw135.

FIG.6illustrates an example process300according to embodiments of the present disclosure. At block301, the process300may include providing a reservoir configured to store a liquid drug, the reservoir comprising a housing including an outer wall defining an interior chamber.

At block302, the process300may include providing a drive mechanism for driving the liquid drug from the reservoir. In some embodiments, the drive mechanism may include a plunger received in the interior chamber of the reservoir, a leadscrew extending from the plunger, and a drive wheel coupled to the leadscrew and operable with a clutch mechanism. The plunger may create a seal against an interior surface of the outer wall of the housing.

At block303, the process300may further include rotating a clutch spring of the clutch mechanism to advance the leadscrew, wherein the clutch mechanism is configured to allow the leadscrew to pass through the clutch spring when in a disengaged position and is configured to grip the leadscrew when in an engaged position. In some embodiments, the process300may further include rotating the drive wheel to rotate the clutch spring to advance the leadscrew and the plunger into the reservoir. In some embodiments, the clutch spring may be provided in direct physical contact with an exterior of the leadscrew when the clutch mechanism is engaged with the leadscrew. In some embodiments, rotating the drive wheel causes the plunger to dispense the fluid from the reservoir.

In some embodiments, the process300may include engaging and disengaging the clutch spring with a spring latch. In some embodiments, the clutch mechanism may be released from the disengaged position by releasing the clutch spring from the spring latch by rotating the drive wheel.

As used herein, the algorithms or computer applications that manage blood glucose levels and insulin therapy may be referred to as an “artificial pancreas” algorithm-based system, or more generally, an artificial pancreas (AP) application. An AP application may be programming code stored in a memory device and that is executable by a processor, controller or computer device.

The techniques described herein for a drug delivery system (e.g., the system100or any components thereof) may be implemented in hardware, software, or any combination thereof. Any component as described herein may be implemented in hardware, software, or any combination thereof. For example, the system100or any components thereof may be implemented in hardware, software, or any combination thereof. Software related implementations of the techniques described herein may include, but are not limited to, firmware, application specific software, or any other type of computer readable instructions that may be executed by one or more processors. Hardware related implementations of the techniques described herein may include, but are not limited to, integrated circuits (ICs), application specific ICs (ASICs), field programmable arrays (FPGAs), and/or programmable logic devices (PLDs). In some examples, the techniques described herein, and/or any system or constituent component described herein may be implemented with a processor executing computer readable instructions stored on one or more memory components.

Certain examples of the present disclosed subject matter were described above. It is, however, expressly noted that the present disclosed subject matter is not limited to those examples, but rather the intention is that additions and modifications to what was expressly described herein are also included within the scope of the disclosed subject matter. Moreover, it is to be understood that the features of the various examples described herein were not mutually exclusive and may exist in various combinations and permutations, even if such combinations or permutations were not made express herein, without departing from the spirit and scope of the disclosed subject matter. In fact, variations, modifications, and other implementations of what was described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the disclosed subject matter. As such, the disclosed subject matter is not to be defined only by the preceding illustrative description.