Patent Description:
Many wearable drug delivery devices include a reservoir for storing a liquid drug. A drive mechanism is operated to expel the stored liquid drug from the reservoir for delivery to a user. Some conventional drive mechanisms use a plunger to expel the liquid drug from the reservoir. Accordingly, the drive mechanism generally has a length equal to a length of the reservoir. And when the reservoir is filled, these wearable drive mechanisms require a length of the drug delivery devices to be significantly larger, for example, about twice the length of the reservoir when the plunger has yet to traverse the length of the reservoir to expel fluid. Increasing the size of the drug delivery devices to accommodate filled reservoirs or pre-filled cartridges and corresponding drive mechanism components leads to bulky devices that are uncomfortable for the user to wear.

Patent application document <CIT> discloses a prior art pumping mechanism employing a bell crank and combining a valving pump with a flow biasing valve.

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

In some approaches, a wearable drug delivery device may include a wearable drug delivery device having a reservoir configured to store a liquid drug, and a delivery pump device including a drive mechanism coupled to the reservoir for receiving the liquid drug. The drive mechanism may include a housing having a pump chamber fluidly connected with a channel chamber, an inlet channel operable to deliver the liquid drug from the reservoir to the channel chamber, and an outlet channel operable to expel the liquid drug from the channel chamber. The drive mechanism may further include a resilient sealing member sealing the pump chamber, and a plunger adjacent the resilient sealing member, wherein the plunger is operable to enter the pump chamber to displace the liquid drug from the pump chamber.

In some approaches, a drive mechanism of a wearable drug delivery device may include a housing having a pump chamber fluidly connected with a channel chamber, an inlet channel operable to deliver a liquid drug from a reservoir of the wearable drug delivery device to the channel chamber, and an outlet channel operable to expel the liquid drug from the channel chamber. The drive mechanism may further include a resilient sealing member sealing the pump chamber, and a plunger adjacent the resilient sealing member, wherein the plunger is operable to enter the pump chamber to expel the liquid drug from the pump chamber.

Furthermore, in some approaches, a method may include coupling a drive mechanism to a reservoir configured to store a liquid drug, the drive mechanism including a housing having a pump chamber fluidly connected with a channel chamber, an inlet channel operable to deliver the liquid drug from the reservoir to the channel chamber, and an outlet channel operable to expel the liquid drug from the channel chamber. The drive mechanism may further include a resilient sealing member sealing the pump chamber, and a plunger adjacent the resilient sealing member. The method may further include biasing the plunger into the pump chamber to displace the liquid drug from the pump chamber.

In the following description, various embodiments of the present disclosure are described with reference to the following drawings, in which:.

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.

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.

Embodiments of the present disclosure provide a drive mechanism of a delivery pump device, the drive mechanism including a pump chamber, sealed with a resilient sealing member, and a complimentary shaped plunger operable to be inserted and withdrawn from the pump chamber. When the plunger is moved into the pump chamber, the resilient sealing member deflects and fills the pump chamber completely, thus displacing a liquid drug therefrom. In some embodiments, the liquid drug is provided to a cannula or microneedle array, e.g., via an outlet channel of a housing of the drive mechanism. The volume of the pump chamber may determine the amount of liquid drug dispensed to a patient. As the plunger is moved out of the pump chamber, the liquid drug may be drawn through an inlet channel from a reservoir of the delivery pump device. In some embodiments, aspiration of the pump chamber is facilitated by the elastomeric properties of the resilient sealing member wanting to return to its natural/original shape.

In some embodiments, the inlet and outlet channels may be fluidly connected by a channel chamber. More specifically, the inlet channel may include an inlet chamber and the outlet channel may include an outlet chamber, wherein the channel chamber extends between the inlet chamber and the outlet chamber. In some embodiments, the inlet chamber and the outlet chamber are sealed by one or more resilient sealing members (e.g., a gasket). The gasket may span both the inlet and outlet chambers, allowing the inlet channel to be blocked but allowing fluid to connect from the pump chamber to the outlet chamber. Conversely, the outlet channel can be blocked by the gasket while the inlet channel is connected to the pump chamber.

In some embodiments, the drive mechanism may include a follower coupled to the housing, wherein the follower is moveable relative to the housing to control movement of the plunger. The follower may be moved in one direction by a shape memory alloy (SMA) wire and biased in a second direction by a return spring. Upon activation/contraction of the SMA wire, the follower is brought into contact with the plunger, thus forcing the plunger towards the resilient sealing member. The SMA wire may continue to contract until a tip of the plunger and the resilient sealing member are fully inserted within the pump chamber, and a fixed volume of the liquid drug is forced through the outlet channel. The fixed volume may be a function of internal chamber geometries and SMA stroke.

When the SMA wire is deactivated, the SMA wire will start to relax and the stored energy of the return spring will cause the follower to spring back to an original position. The motion of the follower in turn causes the plunger and the resilient sealing member to move out of the pump chamber, thus creating a negative pressure differential in the pump chamber and the inlet channel, which causes the liquid drug to be drawn back into the pump chamber. The cycle is then repeated by activating the SMA wire. Advantageously, the delivery pump device of the present disclosure enables a fixed volume of fluid to be delivered and refilled without any secondary steps or additional components. Said another way, the system design and material properties of the SMA wire and the resilient sealing member dictate the fluid response into and out of the pump chamber.

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> illustrates a simplified block diagram of an example system <NUM>. The system <NUM> may be a wearable or on-body drug delivery device and/or an analyte sensor attached to the skin of a patient <NUM>. The system <NUM> may include a controller <NUM>, a pump mechanism <NUM> (hereinafter "pump <NUM>"), and a sensor <NUM>. The sensor <NUM> may be a glucose or other analyte monitor such as, for example, a continuous glucose monitor, and may be incorporated into the wearable device. The sensor <NUM> may, for example, be operable to measure blood glucose (BG) values of a user to generate a measured BG level signal <NUM>. The controller <NUM>, the pump <NUM>, and the sensor <NUM> may be communicatively coupled to one another via a wired or wireless communication path. For example, each of the controller <NUM>, the pump <NUM> and the sensor <NUM> may be equipped with a wireless radio frequency transceiver operable to communicate via one or more communication protocols, such as Bluetooth®, or the like. As will be described in greater detail herein, the system <NUM> may also include a delivery pump device (hereinafter "device") <NUM>, which includes a drive mechanism <NUM> having at least one housing <NUM> defining a pump chamber <NUM>, a channel chamber <NUM>, an inlet channel <NUM>, and an outlet channel <NUM>. The drive mechanism <NUM> may further include a resilient sealing member <NUM> enclosing the pump chamber <NUM>, and a first biasing device <NUM> (e.g., SMA wire) operable to bias or move a plunger <NUM> relative to the pump chamber <NUM>, as will be described in greater detail herein. The system <NUM> may include additional components not shown or described for the sake of brevity.

The controller <NUM> may receive a desired BG level signal, which may be a first signal, indicating a desired BG level or range for the patient <NUM>. The desired BG level may be stored in memory of a controller <NUM> on device <NUM>, received from a user interface to the controller <NUM>, or another device, or by an algorithm within controller <NUM> (or controller <NUM>) that automatically determines a BG level for the patient <NUM>. The sensor <NUM> may be coupled to the patient <NUM> and operable to measure an approximate value of a BG level of the user. In response to the measured BG level or value, the sensor <NUM> may generate a signal indicating the measured BG value. As shown in the example, the controller <NUM> may also receive from the sensor <NUM> via a communication path, the measured BG level signal <NUM>, which may be a second signal.

Based on the desired BG level and the measured BG level signal <NUM>, the controller <NUM> or controller <NUM> may generate one or more control signals for directing operation of the pump <NUM>. For example, one control signal <NUM> from the controller <NUM> or controller <NUM> may cause the pump <NUM> to turn on, or activate one or more power elements <NUM> operably connected with the device <NUM>. As will be described in greater detail herein, in the case where the first biasing device <NUM> is an SMA wire, activation of the SMA wire by the power element <NUM> may cause the SMA wire to change shape and/or length, which in turn will change a configuration of the plunger <NUM> and the resilient sealing member <NUM>. The specified amount of a liquid drug <NUM> (e.g., insulin, GLP-<NUM>, or a co-formulation of insulin and GLP-<NUM>; a chemotherapy drug; a blood thinner; or a pain medication) may then be drawn into the pump chamber <NUM>, through the inlet channel <NUM>, in response to a change in pressure due to the change in configuration of the resilient sealing member <NUM> and the plunger <NUM>. Ideally, the specified amount of the liquid drug <NUM> may be determined based on a difference between the desired BG level and the actual BG level signal <NUM>. The specified amount of the liquid drug <NUM> may 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 pump <NUM>, as determined by the control signal <NUM>, the patient <NUM> may receive the liquid drug from a reservoir <NUM>. The system <NUM> may operate as a closed-loop system, an open-loop system, or as a hybrid system. In an exemplary closed-loop system, the controller <NUM> may direct operation of the device <NUM> without input from the user or controller <NUM>, and may receive BG level signal <NUM> from the sensor <NUM>. The sensor <NUM> may be housed within the device <NUM> or may be housed in a separate device and communicate wirelessly directly with the device <NUM>.

As further shown, the system <NUM> may include a needle deployment component <NUM> in communication with the controller <NUM> or the controller <NUM>. The needle deployment component <NUM> may include a needle and/or cannula <NUM> deployable into the patient <NUM> and may have one or more lumens and one or more holes at a distal end thereof. The cannula <NUM> may form a portion of a fluid path coupling the patient <NUM> to the reservoir <NUM>. More specifically, the inlet channel <NUM> may be coupled to the reservoir <NUM> by a first fluid path component <NUM>. The first fluid path component <NUM> may be of any size and shape and may be made from any material. The first fluid path component <NUM> can allow fluid, such as the liquid drug <NUM> in the reservoir <NUM>, to be transferred to the device <NUM> through the inlet channel <NUM>.

As further shown, the outlet channel <NUM> may be coupled to the cannula <NUM> by a second fluid path component <NUM>. The second fluid path component <NUM> may be of any size and shape and may be made from any material. The second fluid path component <NUM> may be connected to the cannula <NUM> to allow fluid expelled from the device <NUM> to be provided to the patient <NUM>. The first and second fluid path components <NUM> and <NUM> may be rigid or flexible.

The controller <NUM>/<NUM> may be implemented in hardware, software, or any combination thereof. The controller <NUM>/<NUM> may, for example, be a processor, a logic circuit or a microcontroller coupled to a memory. The controller <NUM>/<NUM> may maintain a date and time as well as other functions (e.g., calculations or the like) performed by processors. The controller <NUM>/<NUM> may be operable to execute an artificial pancreas (AP) algorithm stored in memory (not shown) that enables the controller <NUM>/<NUM> to direct operation of the pump <NUM>. For example, the controller <NUM>/<NUM> may be operable to receive an input from the sensor <NUM>, wherein the input comprises analyte level data, such as blood glucose data or levels over time. Based on the analyte level data, the controller <NUM>/<NUM> may modify the behavior of the pump <NUM> and resulting amount of the liquid drug <NUM> to be delivered to the patient <NUM> via the device <NUM>.

In some embodiments, the sensor <NUM> may be, for example, a continuous glucose monitor (CGM). The sensor <NUM> may be physically separate from the pump <NUM>, or may be an integrated component within a same housing thereof. The sensor <NUM> may provide the controller <NUM> with data indicative of measured or detected blood glucose levels of the user.

The power element <NUM> may be a battery, a piezoelectric device, or the like, for supplying electrical power to the device <NUM>. In other embodiments, the power element <NUM>, or an additional power source (not shown), may also supply power to other components of the pump <NUM>, such as the controller <NUM>, memory, the sensor <NUM>, and/or the needle deployment component <NUM>.

In an example, the sensor <NUM> may be a device communicatively coupled to the controller <NUM> and may be operable to measure a blood glucose value at a predetermined time interval, such as approximately every <NUM> minutes, <NUM> minute, or the like. The sensor <NUM> may provide a number of blood glucose measurement values to the AP application.

In some embodiments, the pump <NUM>, when operating in a normal mode of operation, provides insulin stored in the reservoir <NUM> to the patient <NUM> based 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 sensor <NUM> or other functional elements of the system <NUM> or pump <NUM>. For example, the pump <NUM> may contain analog and/or digital circuitry that may be implemented as the controller <NUM>/<NUM> for controlling the delivery of the drug or therapeutic agent. The circuitry used to implement the controller <NUM>/<NUM> may 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 controller <NUM>/<NUM> may execute a control algorithm and other programming code that may make the controller <NUM>/<NUM> operable 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 pre-programmed, for example, into the AP application by the patient <NUM> or 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, or may be calculated iteratively by the controller <NUM> or controller <NUM>, such as every <NUM> minutes.

Although not shown, in some embodiments, the sensor <NUM> may 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 sensor <NUM> may include one or more sensing elements, such as a blood glucose measurement element, 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 to <FIG>, the drive mechanism <NUM> according to embodiments of the present disclosure will be described in greater detail. As shown, the drive mechanism <NUM> may include the housing <NUM> defining the pump chamber <NUM>, the channel chamber <NUM>, the inlet channel <NUM>, and the outlet channel <NUM>. The pump chamber <NUM> and the channel chamber <NUM> may be fluidly connected by an internal channel <NUM>. Although non-limiting, the pump chamber <NUM> may have a bell shape/profile, which compliments the exterior shape/profile of a tip <NUM> of the plunger <NUM>. The channel chamber <NUM> may fluidly connect the inlet channel <NUM> with the outlet channel <NUM>. More specifically, the inlet channel <NUM> may include an inlet chamber <NUM> and the outlet channel <NUM> may include an outlet chamber <NUM>, wherein the channel chamber <NUM> extends between the inlet chamber <NUM> and the outlet chamber <NUM>. Although non-limiting, the channel chamber <NUM> may have a U-shaped profile, as shown, or a substantially straight/horizontal profile.

Coupled to the housing <NUM>, or integrally formed therewith, may be a plunger cylinder <NUM> defining an internal plunger chamber <NUM> configured to receive a shaft <NUM> of the plunger <NUM>. Although not limited to any particular shape or configuration, the plunger <NUM> may include the tip <NUM> at a first end and a flange <NUM> at a second end.

As further shown, the resilient sealing member <NUM> may be positioned across the pump chamber <NUM>, creating a liquid-tight seal between the internal plunger chamber <NUM> and the pump chamber <NUM>. In some embodiments, the resilient sealing member <NUM> is sandwiched between the housing <NUM> and the plunger cylinder <NUM>. Although non-limiting, the resilient sealing member <NUM> may be made from a shape memory polymer, such as a polymeric smart material, which has the ability to return from a temporary deformed/compressed shape to a permanent or natural non-deformed/un-compressed shape. For example, the straight/vertical configuration of the resilient sealing member <NUM> may correspond to its natural or permanent shape.

The drive mechanism <NUM> may further include a switching device <NUM> coupled to the housing <NUM>. In some embodiments, the switching device <NUM> may be a mechanical toggle including a base <NUM> and a rocker <NUM> operable to rotate about a fulcrum <NUM> of the base <NUM> based on a position of a ball <NUM> within a slot <NUM>. As shown, the rocker <NUM> may include a pair of legs 150A, 150B straddling the fulcrum <NUM> and extending into an opening in the base <NUM>. During operation, one of the legs 150A, 150B of the rocker <NUM> may be pressed against a second resilient sealing member <NUM>, depending on the position of the rocker <NUM>, to control flow of the liquid drug through the inlet and outlet channels <NUM>, <NUM>. As shown, the second resilient sealing member <NUM> may extend across the inlet chamber <NUM> and the outlet chamber <NUM>, thus allowing the inlet channel <NUM>, the outlet channel <NUM>, and the internal channel <NUM> to be fluidly connected by the channel chamber <NUM>. In some embodiments, the second resilient sealing member <NUM> may be sandwiched between the housing <NUM> and the base <NUM> of the switching device <NUM>. Although non-limiting, the second resilient sealing member <NUM> may be made from a shape memory polymer, such as a polymeric smart material, which has the ability to return from a temporary deformed/compressed shape to a permanent or natural non-deformed/uncompressed shape. For example, the straight/horizontal configuration of the second resilient sealing member <NUM> may correspond to its natural or permanent shape.

The drive mechanism <NUM> may further include a follower <NUM> coupled to the switching device <NUM> and to the plunger <NUM>. As shown, the follower <NUM> may include a body <NUM> having a first end <NUM> opposite a second end <NUM>. Coupled to the first end <NUM> of the body <NUM> may be the first biasing device <NUM>, (e.g., a SMA wire, motor with lead screw, linear actuator, etc.), and coupled to the second end <NUM> of the body <NUM> may be a second biasing device <NUM> (e.g., return spring). The first biasing device <NUM> may cause the follower <NUM> to move in a first direction and the second biasing device <NUM> may cause the follower <NUM> to move in a second direction, opposite the first direction.

In a case where the first biasing device <NUM> is an SMA wire, the power element <NUM> (<FIG>) may be activated to energize the SMA wire, which causes the SMA wire to change shape (e.g., contract). More specifically, the activated SMA wire begins to shorten, after having previously been passively relaxed, pulling the follower <NUM> and the plunger <NUM> towards the housing <NUM> as the SMA wire strives to return to its memorized or natural/pre-stressed shape and length. In various embodiments, contraction of the SMA wire may be controlled by increasing or decreasing heat generated by the power element <NUM>. For example, a lower current supplied to the SMA wire may cause the follower <NUM> to move more slowly than a higher current.

Although non-limiting, the SMA wire may be linear or may generally be V-shaped or U-shaped, with one end of the SMA wire, or a base of the SMA wire (i.e., the area where both legs meet) coupled to the first end <NUM> of the follower <NUM>. In the latter case, the total force exerted by each leg may be summed, with the total pulling force accordingly doubled for a U or V-shaped arrangement. For a given required total force, thinner SMA wires may accordingly be used, with the electric resistance increasing with decreasing diameter. Further, since the electric resistance depends on the total length of the SMA wire, the electric resistances of a U- or V-shaped arrangement is accordingly double the electric resistance of a single leg of identical diameter. The double leg configuration of the SMA wire accordingly results in a comparatively high electric resistance, which is favorable in order to limit the required current for heating. In other embodiments, alternative folding arrangements are possible, such as a threefold (resulting in an "N-shape") or a fourfold (resulting in an "M-shape").

In some embodiments, the follower <NUM> may include a first engagement wall <NUM> operable to engage the flange <NUM> of the plunger <NUM> and a second engagement wall <NUM> in abutment with a plunger spring <NUM>. As shown, the plunger spring <NUM> may be compressed between the second engagement wall <NUM> and the flange <NUM> of the plunger <NUM> to bias the plunger <NUM> towards the first engagement wall <NUM>. The second biasing device <NUM> may be directly coupled to the second engagement wall <NUM>.

<FIG> illustrate the drive mechanism <NUM> at various stages of a filling and pumping cycle according to embodiments of the present disclosure. Although not demonstrated, the drive mechanism <NUM> may first be primed to fill the pump chamber <NUM>, e.g., by repeatedly cycling in fluid and expelling air from the inlet channel <NUM>, the pump chamber <NUM>, the channel chamber <NUM>, and the outlet channel <NUM>. At the stage demonstrated in <FIG>, the first biasing device <NUM> (e.g., SMA wire) may be inactive, which allows the follower <NUM> to move away from the housing <NUM>, e.g., along direction 'D1,' in response to a force from the second biasing device <NUM>. Movement of the follower <NUM> may cause the ball <NUM> of the switching device <NUM> to roll towards the plunger <NUM>, which in turn may cause the rocker <NUM> to rotate (e.g., clockwise) about the fulcrum <NUM> and the leg 150B of the rocker <NUM> to engage the second resilient sealing member <NUM>. Due to the force from the leg 150B, the second resilient sealing member <NUM> may be deformed or depressed into the inlet chamber <NUM> and against an entrance <NUM> of the inlet channel <NUM>. A seal is created therebetween to prevent further flow of the liquid drug <NUM> from the inlet channel <NUM>.

Furthermore, movement of the follower <NUM> may cause the first engagement wall <NUM> to engage the flange <NUM> of the plunger <NUM>, which in turn may cause the plunger <NUM> to be retracted relative to the pump chamber <NUM> and the resilient sealing member <NUM>. A force from the plunger spring <NUM> may maintain contact between the first engagement wall <NUM> and the flange <NUM> of the plunger <NUM> as the plunger <NUM> moves along direction 'D1'. An amount of the liquid drug <NUM> within the pump chamber <NUM> may change as the resilient sealing member <NUM> changes configuration. For example, in response to movement by the resilient sealing member <NUM> into the flat/vertical position shown, the liquid drug <NUM> may be drawn through the inlet channel <NUM> and into the pump chamber <NUM>. More specifically, negative pressure created in the pump chamber <NUM> by the reconfiguration of the resilient sealing member <NUM> and the plunger <NUM> causes the liquid drug <NUM> to flow through the internal channel <NUM> and into the pump chamber <NUM> while the inlet channel <NUM> remains closed at the entrance <NUM>.

As demonstrated in <FIG>, the first biasing device <NUM> may be activated, e.g., in response to a current received from the power element <NUM> (<FIG>), which causes the follower <NUM> to move towards the housing <NUM>, e.g., along direction 'D2,' overcoming the force of the second biasing device <NUM>. The follower <NUM> and the plunger <NUM> may move towards the housing <NUM> until the flange <NUM> of the plunger <NUM> abuts an end <NUM> of the plunger cylinder <NUM> and the tip <NUM> of the plunger <NUM> is inserted into the pump chamber <NUM>. With the entrance <NUM> to the inlet channel <NUM> closed by the second resilient sealing member <NUM>, the liquid drug <NUM> is displaced from the pump chamber <NUM> and the internal channel <NUM>, and forced towards the channel chamber <NUM> for delivery to the patient via the outlet chamber <NUM> and the outlet channel <NUM>.

As demonstrated in <FIG>, activation of the first biasing device <NUM> continues until the first engagement wall <NUM> of the follower <NUM> separates from the flange <NUM> of the plunger <NUM> and moves into contact with a plunger wall flange <NUM> of the plunger cylinder <NUM>. In some embodiments, the first engagement wall <NUM> may have an opening or recess <NUM>, which allows the first engagement wall <NUM> to pass over an exterior of the plunger cylinder <NUM>. Movement of the follower <NUM> into the configuration shown causes the switching device <NUM> to transition from a first position (shown in <FIG>) to a second position in which leg 150A of the rocker <NUM> depresses the second resilient sealing member <NUM> into the outlet chamber <NUM> and against an entrance <NUM> of the outlet channel <NUM>. More specifically, the ball <NUM> may move within the slot <NUM> towards the first end <NUM> of the follower <NUM> until the rocker <NUM> rotates (e.g., counterclockwise) about the fulcrum <NUM>. As a result, a liquid-tight seal is created across the entrance <NUM> of the outlet channel <NUM> to prevent further flow of the liquid drug <NUM> from the channel chamber <NUM> to the outlet channel <NUM>.

In some embodiments, deactivation of the SMA wire of the first biasing device <NUM>, e.g., by the controller <NUM> (<FIG>), may occur following expiration of a predetermined time period triggered by the initial activation of the SMA wire. The predetermined time period may be sufficient to allow a controlled dose (e.g.,. <NUM>) of the liquid drug <NUM> to enter and then be discharged from the pump chamber <NUM>, and then delivered to the patient <NUM> via the cannula <NUM>.

As demonstrated in <FIG>, the second biasing device <NUM> may pull the follower <NUM> away from the housing <NUM>, e.g., along direction 'D1,' which causes the first engagement wall <NUM> to move from the plunger wall flange <NUM> of the plunger cylinder <NUM> to the flange <NUM> of the plunger <NUM>. In some embodiments, when the first biasing device <NUM> is an SMA wire, current to the SMA wire is decreased or discontinued to relax/elongate the SMA wire, which allows the force of the second biasing device <NUM> pull the follower <NUM> along direction 'D1. ' As shown, a force on the flange <NUM> from the first engagement wall <NUM> may cause the tip <NUM> of the plunger <NUM> to retract from the pump chamber <NUM>. Negative pressure created as the plunger <NUM> is retracted from the internal plunger chamber <NUM> causes the liquid drug <NUM> to be drawn through the inlet channel <NUM> again. More specifically, an amount of the liquid drug <NUM> within the pump chamber <NUM> may change as the resilient sealing member <NUM> changes configuration. For example, in response to movement by the resilient sealing member <NUM> into the flat/vertical position shown, the liquid drug will be drawn through the inlet channel <NUM> and into the pump chamber <NUM> via the inlet chamber <NUM> and the internal channel <NUM>.

<FIG> illustrate an alternative drive mechanism <NUM> according to embodiments of the present disclosure. The drive mechanism <NUM> may be part of a delivery pump device, such as delivery pump device <NUM> of <FIG>. As shown, the drive mechanism <NUM> may include a housing <NUM> defining a pump chamber <NUM>, a channel chamber or pathway <NUM>, an inlet channel <NUM> fluidly connected with a reservoir (not shown), and an outlet channel <NUM> for delivering a liquid drug to a patient, e.g., via a cannula. The inlet channel <NUM> may be connected with an inlet valve <NUM>, and the outlet channel <NUM> may be connected with an outlet valve <NUM>. In some embodiments, the pump chamber <NUM> and the second pathway <NUM> may be fluidly connected by an internal channel <NUM> through the housing <NUM>. Although non-limiting, the pump chamber <NUM> may have a bell shape/profile to receive a correspondingly shaped tip <NUM> of a plunger <NUM>.

As shown, the housing <NUM> may include a plunger cylinder <NUM> defining an internal plunger chamber <NUM> configured to receive a shaft <NUM> of the plunger <NUM>. The plunger <NUM> may further include a flange <NUM> in contact with a plunger spring <NUM>. The flange <NUM> and the plunger spring <NUM> may be positioned within a cavity <NUM> of a follower <NUM>, wherein the follower <NUM> is coupled to the housing <NUM>. In some embodiments, an engagement wall <NUM> of the follower <NUM> may be in contact with the flange <NUM> of the plunger <NUM>.

As further shown, the drive mechanism <NUM> may include a resilient sealing member <NUM> positioned across the pump chamber <NUM>, creating a liquid-tight seal between the internal plunger chamber <NUM> and the pump chamber <NUM>. In some embodiments, the resilient sealing member <NUM> is directly coupled to the housing <NUM>. Although non-limiting, the resilient sealing member <NUM> may be made from a shape memory polymer, such as a polymeric smart material, which has the ability to return from a temporary deformed/compressed shape to a permanent or natural, undeformed shape. For example, the straight/vertical configuration of the resilient sealing member <NUM> may correspond to its natural or permanent shape.

The drive mechanism <NUM> may further include a switching device <NUM> coupled to the housing <NUM>. In some embodiments, the switching device <NUM> may be a mechanical toggle including a base <NUM>, a rocker <NUM>, and a bias <NUM>. In some embodiments, the bias <NUM> is loaded by a spring <NUM>. As shown, the rocker <NUM> may include a pair of legs 250A, 250B extending into corresponding openings <NUM> of the base <NUM>. During operation, one of the legs 250A, 250B of the rocker <NUM> may be pressed against a second resilient sealing member <NUM> depending on the position of the rocker <NUM>. Although non-limiting, the second resilient sealing member <NUM> may be made from a shape memory polymer, such as a polymeric smart material, which has the ability to return from a temporary deformed/compressed shape to a permanent or natural, undeformed shape. For example, the straight/horizontal configuration of the second resilient sealing member <NUM> may correspond to its natural or permanent shape.

As shown, an arm <NUM> of the rocker <NUM> may extend through an opening <NUM> of the follower <NUM>. The follower <NUM> may include a body <NUM> having a first end <NUM> opposite a second end <NUM>. Coupled to the first end <NUM> may be a first biasing device <NUM>, (e.g., an SMA wire, motor with lead screw, or linear actuator), and coupled to the second end <NUM> may be a second biasing device <NUM> (e.g., a return spring). The first biasing device <NUM> may cause the follower <NUM> to move in a first direction 'D1', and the second biasing device <NUM> may cause the follower <NUM> to move in a second direction 'D2', opposite the first direction.

In the case the first biasing device <NUM> is an SMA wire, a power element (e.g., power element <NUM> in <FIG>) may be activated to energize the SMA wire, which causes the SMA wire to change shape (e.g., contract). More specifically, the activated SMA wire begins to shorten, after having previously been passively relaxed, pulling the follower <NUM> and the plunger <NUM> along direction 'D1' as the SMA wire strives to return to its memorized or natural/pre-stressed shape and length. In various embodiments, contraction of the SMA wire may be controlled by increasing or decreasing heat generated by the power element. For example, a lower current supplied to the SMA wire may cause the follower <NUM> to move more slowly than a higher current.

At the stage demonstrated in <FIG>, the first biasing device <NUM> may be inactive, which allows the second biasing device <NUM> to pull the follower <NUM> along direction 'D2,' thus causing the rocker <NUM> to rotate (e.g. counterclockwise) about a center pin <NUM>. Due to the force from the bias <NUM> on the leg 250A, the second resilient sealing member <NUM> may be deformed or depressed against the inlet valve <NUM> to create a liquid-tight seal therebetween, which prevents further flow of a liquid drug from the inlet channel <NUM>. As further shown, the plunger <NUM> is retracted relative to the pump chamber <NUM> and the resilient sealing member <NUM>, which may cause the liquid drug to fill the pump chamber <NUM>. A force from the plunger spring <NUM> may maintain contact between the engagement wall <NUM> of the follower <NUM> and the flange <NUM> of the plunger <NUM> as the plunger <NUM> moves out of the plunger cylinder <NUM>.

As demonstrated in <FIG>, the first biasing device <NUM> may be activated, e.g., in response to a current received from the power element, which causes the follower <NUM> to start moving along direction 'D1'. The plunger <NUM> moves together with the follower <NUM>, causing the plunger <NUM> to travel within the internal plunger chamber <NUM> and towards the resilient sealing member <NUM>. Activation of the first biasing device <NUM> continues, as demonstrated in <FIG>, which causes the tip <NUM> of the plunger <NUM> and the resilient sealing member <NUM> to fully enter the pump chamber <NUM> and expel the liquid drug therefrom. A force from the plunger <NUM> may cause the liquid drug to travel through the second pathway <NUM>, through the outlet valve <NUM>, and out through the outlet channel <NUM>. As the rocker <NUM> is further rotated by the follower <NUM>, the inlet valve <NUM> is opened and the outlet valve <NUM> is closed, thus preventing the liquid from exiting through the outlet channel <NUM>.

<FIG> illustrates an example process <NUM> according to embodiments of the present disclosure. At block <NUM>, the process <NUM> may include coupling a drive mechanism to a reservoir configured to store a liquid drug. In some embodiments, the drive mechanism is part of a wearable drug delivery device. The drive mechanism may include a housing having a pump chamber fluidly connected with a channel chamber, an inlet channel operable to deliver the liquid drug from the reservoir to the channel chamber, and an outlet channel operable to expel the liquid drug from the channel chamber. The drive mechanism may further include a resilient sealing member sealing the pump chamber, and a plunger adjacent the resilient sealing member. In some embodiments, the resilient sealing member are directly attached/coupled to one another.

At block <NUM>, the process <NUM> may include moving the plunger away from the resilient sealing member to fill the pump chamber, while the outlet channel is closed, in response to a negative pressure created within the pump chamber. In some embodiments, the plunger is coupled to a follower, which is biasable in a first direction by a first biasing device and in a second direction by a second biasing device. In some embodiments, the first biasing device is an SMA wire, wherein deactivating the SMA wire may cause the follower and the plunger to move away from the housing.

At block <NUM>, the process <NUM> may further include activating the first biasing device to cause the follower and the plunger to move towards the pump chamber. In some embodiments, a mechanical rocker device transitions from a first position in which a second resilient sealing member is biased against the outlet channel, to a second position in which the second resilient sealing member is biased against the inlet channel. In some embodiments, the follower is coupled to the mechanical rocker device, wherein movement of the follower relative to the housing causes the mechanical rocker device to transition between the first and second positions.

At block <NUM>, the process <NUM> may further include biasing the plunger into the pump chamber to displace the liquid drug from the pump chamber. In some embodiments, the liquid drug is forced from the pump chamber, through an internal channel of the housing and the channel chamber, and out through the outlet channel for delivery to patient, e.g., via a cannula. The SMA wire may then be de-activated again to move the plunger and the resilient sealing member from within the pump chamber to a neutral/natural position, to draw in more liquid drug, thus repeating the cycle. In some embodiments, deactivation of the SMA wire, e.g., by a controller, may occur following expiration of a predetermined time period triggered by the initial activation of the SMA wire. The predetermined time period may be sufficient to allow a controlled dose (e.g., <NUM> or <NUM>) of the liquid drug to enter and then be extinguished from the pump chamber. Alternatively, deactivation may be triggered when the resilient sealing member reaches a particular position within the pump chamber, or when the plunger reaches a particular position within the plunger chamber. For example, electrodes may be placed within a flange of the plunger and in the end of the plunger cylinder to determine a relative position of the flange, which may cause the controller of the drug delivery device to take a certain action, such as de-activation of the SMA wire.

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 system <NUM> or 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 system <NUM> or 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.

Some examples of the disclosed devices may be implemented, for example, using a storage medium, a computer-readable medium, or an article of manufacture which may store an instruction or a set of instructions that, if executed by a machine (i.e., processor or controller), may cause the machine to perform a method and/or operation in accordance with examples of the disclosure. Such a machine may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. The computer-readable medium or article may include, for example, any suitable type of memory unit, memory, memory article, memory medium, storage device, storage article, storage medium and/or storage unit, for example, memory (including non-transitory memory), removable or non-removable media, erasable or non-erasable media, writeable or re-writeable media, digital or analog media, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW), optical disk, magnetic media, magneto-optical media, removable memory cards or disks, various types of Digital Versatile Disk (DVD), a tape, a cassette, or the like. The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, programming code, and the like, implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language. The non-transitory computer readable medium embodied programming code may cause a processor when executing the programming code to perform functions, such as those described herein.

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.

Program aspects of the technology may be thought of as "products" or "articles of manufacture" typically in the form of executable code and/or associated data that is carried on or embodied in a type of machine readable medium. Storage type media include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. It is emphasized that the Abstract of the Disclosure is provided to allow a reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features are grouped together in a single example for streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed example. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate example. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein," respectively. Moreover, the terms "first," "second," "third," and so forth, are used merely as labels and are not intended to impose numerical requirements on their objects.

Claim 1:
A drive mechanism (<NUM>) of a wearable drug delivery device (<NUM>), the drive mechanism (<NUM>) comprising:
a housing (<NUM>) comprising:
a pump chamber (<NUM>) fluidly connected with a channel chamber (<NUM>);
an inlet channel (<NUM>) operable to deliver a liquid drug from a reservoir of the wearable drug delivery device to the channel chamber (<NUM>); and
an outlet channel (<NUM>) operable to expel the liquid drug from the channel chamber (<NUM>);
a resilient sealing member (<NUM>) sealing the pump chamber (<NUM>); and
a plunger (<NUM>) adjacent the resilient sealing member (<NUM>), wherein the plunger (<NUM>) is operable to enter the pump chamber (<NUM>) to expel the liquid drug from the pump chamber (<NUM>);
and a second resilient sealing member (<NUM>) positioned within the channel chamber (<NUM>),
wherein the second resilient sealing member (<NUM>) is operable to seal the inlet channel (<NUM>) and the outlet channel (<NUM>);
characterised in that
the drive mechanism (<NUM>) further comprises
a mechanical rocker device (<NUM>), wherein in a first position the mechanical rocker device (<NUM>) biases the second resilient sealing member (<NUM>) against an entrance (<NUM>) of the inlet channel (<NUM>), and wherein in a second position the mechanical rocker device (<NUM>) biases the second resilient sealing member (<NUM>) against an entrance (<NUM>) of the outlet channel (<NUM>).