Wearable drug delivery device with pressurized fluid dispensing

A drug delivery device has a housing with an adhesive pad associated with the lower surface of the housing and configured to removably attach to a human body surface. A drug reservoir is positioned within the housing and includes an outlet with a valve, with a needle fluidically connected to the reservoir and configured to define at least a portion of a fluid flow path between the reservoir and the human body surface. A controller is configured to control the components of the drug delivery device to execute a drug delivery routine. The drug delivery device also includes pressurized fluid positioned to apply a force to the reservoir. The controller moves the valve from a closed condition to an open condition during a drug delivery routine to allow the pressurized fluid to deform the reservoir or move a plunger to convey the drug out of the reservoir via the outlet.

BACKGROUND

Field of the Disclosure

The present disclosure relates to drug delivery devices. More particularly, the present disclosure relates to devices mounted to the body utilizing pressurized fluid to deliver a drug to a patient.

Description of Related Art

Delivery of liquid drugs to a patient via injection using a needle or syringe is well-known. More recently, devices that automate the delivery of liquid drugs have been introduced. These devices (which are commonly referred to as “on-body devices” or “on-body injectors”) are mounted or otherwise secured to the body of the patient (e.g., to the arm or abdomen) and remain in place for an extended amount of time (on the order of hours or days), injecting an amount of the drug into the body of the patient at one or more scheduled times. For example, a device may be configured to deliver a drug over the span of 45 minutes, with delivery beginning 27 hours after the device has been activated and applied to a patient (to ensure that the drug is not delivered sooner than 24 hours after a medical procedure or treatment). These devices improve upon manual methods by obviating the need for the patient to inject themselves with the drug (which carries heightened risks of the patient improperly administering the injection or injecting the drug at an inappropriate time) or to return to a medical facility for one or more injections by a technician or medical professional.

One known on-body device10is shown inFIGS. 1 and 2. The device10ofFIG. 1includes a housing12that contains or encloses the functional components of the device10, which are shown inFIGS. 3 and 4.

The internal components of the device10include a reservoir14that is configured to be filled with a liquid drug to be delivered to the patient. An upper surface of the housing12includes a fill indicator16that provides a visual indication of the amount of fluid in the reservoir14. In addition to the fill indicator16, the upper surface of the housing12may include printed information, such as information regarding the drug to be delivered. The upper surface of the housing12may be formed of a translucent material, which allows light from a status light18(which may be configured as a light-emitting diode) mounted within the housing12(FIG. 1) to be seen through the upper surface of the housing12. The status light18is electrically coupled to a controller or processor (which may be a CPU or MPU configured as a computer chip mounted to a printed circuit board positioned within the housing12, for example) that carries software for executing a drug delivery routine. The status light18receives signals from the controller and emits light to provide information regarding a status of the device10. This may include emitting differently colored light and/or emitting light in different flashing patterns to indicate different conditions, such as a blinking orange light to indicate that the device10is ready to be applied to a patient, a blinking green light to indicate proper operation of the device10, and a blinking red light to indicate an error or other condition. One or more batteries20provides power to the status light18and the other electrical components of the device10.

The drug is injected into the reservoir14using a (typically pre-filled) syringe22via a port24incorporated into the bottom or underside of the housing12(FIG. 4) and fluidically connected to the reservoir14.FIGS. 1 and 2illustrate an applicator26that is removably associated with the underside of the housing12and used in combination with the syringe22to fill the reservoir14via the port24. The drug is most typically injected into the reservoir14by a medical professional immediately before the device10is secured to the patient to ensure that the proper drug is supplied, along with the proper amount.

A piston or plunger28(FIG. 4) positioned within the reservoir14is moved (from left to right, in the orientation ofFIG. 4) as the space within the reservoir14is filled by the inflowing drug. Movement of the piston28into its final position (when the reservoir14has been filled with the appropriate amount of the drug) causes a portion of a rod associated with the piston28to extend from the reservoir14to create an electrical connection, which activates the device10. Activation of the device10may include a signal, such as a buzzer providing an audible indication that the device10has been activated and/or a light emitted by the status light18.

When the device10has been activated, it is mounted or secured to the body of the patient. The applicator26is first removed from the underside of the housing12and discarded, followed by a pull tab30being manipulated to remove a release film from an adhesive pad32associated with the underside of the housing12. The housing12is then pressed against the body of the patient, with the adhesive pad32facing the body. An adhesive present on the adhesive pad32causes the adhesive pad32(and, hence, the housing12) to adhere to the body.

Some predetermined time after the device10has been activated (which may be on the order of three to five minutes, for example), a distal end portion of a cannula34is introduced into the skin of the patient via a cannula window36defined in the housing12(FIGS. 3 and 4). The cannula34(which remains partially positioned within the skin of the patient for as long as the device10is in use) is formed of a flexible or semi-rigid material, such as a plastic material, for improved patient comfort.

As the cannula34is not itself configured to pierce the skin, an associated needle38is provided within the lumen of the cannula34, with a sharp or beveled distal end of the needle38extending out of a distal end of the cannula34. A midsection of the needle38is mounted within a needle carriage40, while a proximal end42of the cannula34is mounted within a cannula carriage44that is initially positioned directly adjacent to the needle carriage40. The needle carriage40is pivotally connected to an end of a linkage or crank arm46, with an opposite end of the linkage46being associated with a torsion spring48. At the designated time (e.g., 3-5 minutes after the device10has been activated), the controller causes a lever (not visible) to be released, which allows the spring48to recoil, in turn rotating the linkage46, which rotation causes the needle carriage40to move along a linear track50from a first position adjacent to the spring48(FIG. 3) to a second position spaced away from the spring48. Movement of the needle carriage40causes corresponding movement of the cannula carriage44along the track50, with the cannula34and the distal portion of the needle38moving together in a direction away from the spring48. Moving the carriages40and44into the second position causes the sharp distal end of the needle38to advance out of the housing12via the cannula window36and pierce the skin. The cannula34is carried by or moves along with the distal portion of the needle38, such that the needle38piercing the skin will also cause the distal end of the cannula34to enter into the skin.

Continued recoiling of the spring48causes further rotation of the linkage46, which has the effect of moving the needle carriage40back toward the spring48(i.e., back toward its first position). Rather than moving along with the needle carriage40, the cannula carriage44is held in its second position (FIG. 3) by a lock or latch52. As the movement of the needle carriage40is not restricted by the lock or latch52, the needle carriage40will return to its first position, while the cannula carriage44remains in its second position (with the final positions of both carriages40and44shown inFIG. 3).

Movement of the needle carriage40in a proximal direction away from the cannula carriage44causes the needle38to partially (but not fully) retract from the cannula34. In the final condition shown inFIG. 3, the distal end of the needle38is positioned within the cannula34(e.g., adjacent to a midsection or midpoint of the cannula34), while the distal end of the cannula34remains positioned within the skin. A proximal end of the needle38extends into fluid communication with the reservoir14, such that the needle38provides a fluid path from the reservoir14to the cannula34when the carriages40and44are in the final condition illustrated inFIG. 3. Due to the distal end of the cannula34remaining positioned within the skin, subsequent advancement of the drug out of the reservoir14(e.g., 27 hours after the device10has been activated) will cause the drug to move into the needle38(via the proximal end of the needle38), through the needle38(to its distal end), and into the cannula34. The drug is then delivered to the patient (e.g., over the course of a 45-minute session) via the distal end of the cannula34positioned within the skin.

As for the mechanism by which the drug is advanced out of the reservoir14, the device10includes a lever54mounted to a pivot point56(FIG. 4). The lever54includes a first arm58configured and oriented to interact with a first gear60and a second arm62configured and oriented to interact with a second gear64. A tab66extends from an opposite end of the lever54and is configured and oriented to alternately move into and out of contact with two electrical contacts68and70(electrically coupled to a printed circuit board, which is not shown) as the lever54pivots about the pivot point56.

A first wire or filament72extends from the lever54, around a first pulley74, and into association with a first electrical contact76. A second wire or filament78extends from the lever54in the opposite direction of the first wire72, around a second pulley80, and into association with a second electrical contact82. The wires72and78(which are commonly referred to as “muscle wires”) are formed of a shape memory alloy (e.g., Nitinol), which causes them to heat up and contract when a current flows through them, while being allowed to stretch when the current is removed and the wire72,78cools. Current is alternately applied to the two wires72and78, causing the one carrying a current to heat up and contract while the other one is allowed to stretch. The wire72,78that contacts will pull on the lever54, causing it to pivot about the pivot point56. Thus, alternately applying current to the two wires72and78will cause the wires72and78to alternately contact and stretch, which in turn causes the lever54to pivot back and forth about the pivot point56.

At the designated time (e.g., 27 hours after the device10has been activated), the controller provides commands that cause current to be alternately applied to the muscle wires72and78, which causes the lever54to alternately pivot about the pivot point56in opposite first and second directions. Pivotal movement of the lever54in the first direction will cause the first arm58of the lever54to engage and rotate the first gear60an incremental amount, while pivotal movement of the lever54in the second direction will cause the second arm62of the lever54to engage and rotate the second gear64an incremental amount (in the same direction in which the first gear60is rotated by the first arm58). Both gears60and64are associated with a common shaft84(which is shown inFIG. 3and may be formed with the gears60and64as a single, molded piece), such that rotation of either gear60,64will cause the shaft84to rotate about its central axis. The shaft84is mechanically coupled to the piston28within the reservoir14, with rotation of the shaft84causing the piston28to move toward its initial position (e.g., by a threaded connection whereby rotation of the shaft84is translated into movement of the piston28along the length of the reservoir14). As the piston28moves toward its initial position (from right to left in the orientation ofFIG. 4), it will force the drug out of the reservoir14via the proximal end of the needle38. As described above, the drug will flow through the needle38, into and through the cannula34, and into the body of the patient.

After the drug has been delivered (e.g., over the course of a 45-minute session), the controller alerts the patient via a visual cue from the status light18and/or an audible cue from the buzzer that drug delivery is complete. Subsequently, the patient removes the device10from their skin and discards the device10.

While devices of the type described above have proven adequate, there is room for improvement of them. For example, the size and the profile of the device can be greatly improved. This can be done by reducing the size of the drug reservoir and/or reducing the on-board power requirement with alternate force mechanisms. A lower and more compact profile can provide a more comfortable device for the user and reduce instances of devices being caught on clothing, preventing accidental leakage from the device.

SUMMARY

In one aspect, a drug delivery device comprises a housing, an adhesive pad associated with the lower surface of the housing and configured to removably attach to a human body surface, a deformable drug reservoir positioned within the housing and including an outlet with a valve, and a needle fluidically connected to the drug reservoir and configured to define at least a portion of a fluid flow path between the drug reservoir and said human body surface. The drug delivery device also includes a controller configured to control the components of the drug delivery device to execute a drug delivery routine and a pressurized fluid positioned between the housing and the drug reservoir. The controller is configured to control the valve to move from a closed condition to an open condition during said drug delivery routine so as to allow the pressurized fluid to deform the drug reservoir, thereby conveying a drug out of the drug reservoir via the outlet.

In another aspect, a drug delivery device comprises a housing, an adhesive pad associated with the lower surface of the housing and configured to removably attach to a human body surface, a drug reservoir positioned within the housing and including an outlet with a valve, a plunger positioned within the drug reservoir, separating an interior of the drug reservoir into first and second chambers, and a needle fluidically connected to the drug reservoir and configured to define at least a portion of a fluid flow path between the drug reservoir and said human body surface. The drug delivery device also includes a controller configured to control the components of the drug delivery device to execute a drug delivery routine and a pressurized fluid positioned within the first chamber of the drug reservoir. The controller is configured to control the valve to move from a closed condition to an open condition during said drug delivery routine so as to allow the pressurized fluid to move the plunger toward the outlet, thereby conveying a drug positioned within the second chamber out of the drug reservoir via the outlet.

This and other aspects of the present subject matter are set forth in the following detailed description of the accompanying drawings.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The embodiments disclosed herein are for the purpose of providing a description of the present subject matter, and it is understood that the subject matter may be embodied in various other forms and combinations not shown in detail. Therefore, specific designs and features disclosed herein are not to be interpreted as limiting the subject matter as defined in the accompanying claims.

In contrast to the conventional device described above and shown inFIGS. 1-4, devices according to the present disclosure employ pressurized fluid to convey a drug out of a drug reservoir. One advantage of such an approach is its versatility, as differently configured drug reservoirs may be used in combination with a pressurized fluid, which may include a deformable drug reservoir (FIGS. 5 and 6) and a generally rigid drug reservoir (FIGS. 7 and 8), though it should be understood that the illustrated drug reservoir and pressurized fluid combinations are merely exemplary and that other combinations may be employed without departing from the scope of the present disclosure. Another advantage of the use of pressurized fluid is that it allows for a reduction in the number of (possibly bulky) mechanical parts required to be incorporated into a device, which in turn allows for the device to be smaller. This may include a reduction in the size of an onboard battery or power source, as less power may be needed to execute a drug delivery routine than is required by a conventional device with more mechanical components.

While the drug reservoir ofFIGS. 5 and 6differs from the drug reservoir ofFIGS. 7 and 8(as will be explained in greater detail), the respective drug delivery devices110and210may otherwise be similarly configured, with similar components being numbered similarly throughout the Figures. In both embodiments, the drug delivery device110/210includes a housing116/216. The housing116/216contains or encloses the functional components of the device110/210, including a controller118/218and the drug reservoir112/212. The reservoir112/212is configured to be filled with a liquid drug to be delivered to a patient, with the reservoir112/212being filled either before or after the reservoir112/212is mounted within the housing116/216, which may include the reservoir112/212being filled by a medical professional shortly before the device110/210is activated for a drug delivery routine.

The device110/210also includes a needle fluidically connected to the drug reservoir112/212and configured to define at least a portion of a fluid flow path between the drug reservoir112/212and a subject or patient. The needle and fluid flow path may be variously configured without departing from the scope of the present disclosure, with the needle and flow path being generally configured as described above with regard to the device ofFIGS. 1-4in exemplary embodiments. The housing116/216has an adhesive pad114/214associated with its lower surface and configured to removably attach to a human body surface. The adhesive can be a pressure sensitive adhesive, particularly any medical grade pressure sensitive adhesive. The adhesive can be rubber, acrylic, and/or silicone based, for example.

The controller118/218is configured to control the components of the drug delivery device110/210to execute a drug delivery routine. The controller118/218may include a microprocessor (which, in fact may include multiple physical and/or virtual processors) and one or more electrical circuits and memories. The instructions by which the microprocessor is programmed may be stored on the one or more memories associated with the microprocessor, which memory/memories may include one or more tangible non-transitory computer readable memories, having computer executable instructions stored thereon, which when executed by the microprocessor, may cause the microprocessor to carry out one or more actions as described below.

The device110/210may also include at least one indicium associated with a display of the device. The indicium is configured to provide information to a user, which may include for example an indication that the device is ready to begin a drug delivery procedure, that the device is performing a drug delivery procedure, that the device has completed a drug delivery procedure, and/or that there has been an error. The indicium may display or represent the status of the device in any suitable manner. For example, in one embodiment, an indicium may be configured as a shortened message that can display different words, and it may include colors and/or lights to further indicate the state of the device. The indicium may utilize any other type of indication known in the art without departing from the scope of the present disclosure.

The controller118/218may be coupled (directly or indirectly connected) to the components of the device110/210, such as the needle and display. The controller may operate each component, each of which may be an assembly of other devices or equipment, to execute a drug delivery routine. The controller may be programmed to perform other actions as well. Among the components coupled to the controller is a valve160/260configured to move to allow the drug to be conveyed from the drug reservoir via an outlet, as will be described in greater detail herein.

The device110/210can also include buttons or icons associated with the controller118/218. The buttons or icons may be variously configured and positioned at any suitable location of the device. The device may include two buttons or icons, for example, with one button/icon being a start button/icon for initializing a procedure and the other button/icon of the set being a stop button/icon for stopping a procedure.

As noted above, the drug reservoir can be a deformable drug reservoir112associated with an external pressurized fluid (FIGS. 5 and 6) or a generally rigid drug reservoir212with pressurized fluid within the reservoir (FIGS. 7 and 8). In the embodiment ofFIGS. 5 and 6, the drug reservoir112is at least partially deformable and/or flexible. The drug reservoir112can be any appropriate shape, being generally rectangular with curved or rounded corners in the illustrated embodiment. In an exemplary embodiment, the drug reservoir is configured as a large, flat, flexible bag formed of two films sealed together along at least one edge, and possibly all four edges, of the reservoir or a single film sealed along at least one edge. The reservoir may extend to occupy a significant portion of the length and width of the interior of the housing, which may be advantageous by decreasing the height of the reservoir without decreasing its capacity. For example, the reservoir (when filled with a drug122) may have a height that is less than half the height of a conventional rigid reservoir (which may be in the range of about 6 mm to about 18 mm). By changing the size/shape of the reservoir from a traditional “syringe-style” reservoir with a round or oval cross-section (as employed in the device ofFIGS. 1-4), the delivery device can be much lower profile, making it is less likely to be caught on clothing and/or dislodge, which can lead to leaking.

The drug reservoir112may be formed of any suitable material or combination of materials, along with being defined by a single layer or multiple layers of different materials. In an exemplary embodiment, the reservoir is formed of one or more film layers comprised of any one or more of a variety of materials, including thermoplastic materials and elastomers. Suitable materials can include (without limitation) polyethylene, polypropylene, polyurethanes, polyamides, polyesters, ethylene vinyl acetate, natural or synthetic polyisoprene, polybutadiene, polychloroprene, silicone, nitrile rubbers, nylon, olefin, and polyvinyl chloride. The film layer or layers can be comprised of blends or combinations of any of the preceding materials. Different layers of the film can be comprised of the same material or material combinations or different materials or material combinations.

A pressurized fluid130(FIG. 6) is positioned within the housing116, between the housing116and the drug reservoir112so as to apply a compressive force to at least a portion of the drug reservoir112. The pressurized fluid130can be any applicable fluid known in the art, which may include the pressurized fluid130being a gas or liquid. In the case of a pressurized fluid130provided as a gas, it may be a compressed gas including, but not limited to, propane, nitrogen, chlorine, helium, and oxygen. In some embodiments, the gas is air or nitrogen. In the case of a pressurized fluid130provided as a liquid, it may be a liquified gas, such as anhydrous ammonia, chlorine, propane, nitrous oxide, or carbon dioxide, for example. The pressurized fluid130can be pressurized during manufacturing and/or assembly of the drug delivery device110. This can be accomplished by adding a specific amount of fluid to the device or by adjusting the temperature of the fluid (e.g., by increasing it) to achieve the desired pressure level, for example.

In the embodiment ofFIGS. 7 and 8, the drug reservoir212is formed of a generally rigid material, which may include one or more of the materials described above in relation to the deformable drug reservoir112ofFIGS. 5 and 6, but can also include more rigid materials, such as various plastics, glass, or metal. The drug reservoir212is illustrated as a cylinder having a circular or oval cross-sectional shape, but it should be understood that the drug reservoir212may be differently shaped without departing from the scope of the present disclosure.

A plunger240is movably positioned within the drug reservoir212to separate the interior of the drug reservoir212into first and second chambers or compartments242and244. A pressurized fluid230is maintained within one of the chambers242of the reservoir212, while a liquid drug222is positioned within the other chamber244. The pressurized fluid230(which may be configured and provided as described above with regard to the pressurized fluid130of the embodiment ofFIGS. 5 and 6, for example) tends to urge the plunger240in a direction from the first chamber242toward the second chamber242(i.e., to press the plunger240against the liquid drug222).

Movement of the plunger240corresponds to movement or release of the drug222from the drug reservoir212. The plunger240is at least movable from a first position to a second position, but may also be movable between the first and second positions (i.e., reversible movement), moving longitudinally relative to the housing of the drug delivery device. The first position of the plunger240is farther from an outlet of the drug reservoir212than the second position, as can be seen inFIG. 7(first position) andFIG. 8(movement from the first position toward the second position), with the second plunger position being between the outlet and the first position, such as directly adjacent to the outlet. The second chamber244of the drug reservoir212may be at its maximum volume, retaining substantially all of the drug222, when the plunger240is in the first position (with the volume of the first chamber242being relatively small), and at its minimum volume, being empty or at least substantially empty, when the plunger240is in the second position (with the volume of the first chamber242being greater than when the plunger240is in its first position). The plunger may also be moved into a third position, between the first and second positions, as shown inFIG. 8. The plunger may further be moved into additional positions without departing from the scope of the present disclosure, with the controller able to stop movement of the plunger in each and/or any of these positions.

The first chamber242may either be sealed (entrapping the pressurized fluid130within the chamber) or in fluid communication with a source of pressurized fluid130(allowing the pressurized fluid to be conveyed between the reservoir and the source to vary the pressure of the fluid within the chamber). When the first chamber242is sealed, the force applied by the pressurized fluid230to the plunger240will remain substantially constant (until the plunger240is moved, increasing the volume of the first chamber242), whereas the force applied to the plunger240(at a given plunger position) may be varied when the amount of pressurized fluid230in the first chamber242may be varied (by alternately conveying an amount of fluid between the first chamber and the fluid source).

In both of the embodiments shown inFIGS. 5-8, the pressurized fluid130//230applies force tending to convey a drug122/222from the drug reservoir112/212via an outlet132/232. The outlet132/232may be located at, incorporated into, or otherwise associated with one edge of the drug reservoir112/212, for example. In the embodiment ofFIGS. 7 and 8, the outlet232opens into the second chamber242of the drug reservoir212(i.e., the chamber in which the drug222is positioned). The outlet132/232includes an opening of the reservoir112/212and may also include a conduit134/234, such as a tube or tubing that is sized to fit securely in the opening of the drug reservoir112/212. If provided, the tube or tubing may be formed of any of a variety of materials, including being formed of a generally rigid material or combination of materials and being formed of a generally deformable or flexible material or combination of materials. By way of example, the conduit may be formed of a polymeric material, such as a plastic or rubber polymer, polyvinyl chloride, polyethylene, or a combination of these. The opening of the drug reservoir may also be deformable, particularly when the reservoir itself is formed of a deformable or flexible material. The opening and conduit define a portion of the fluid flow path from the drug reservoir to the needle of the drug delivery device.

Due to the tendency of the pressurized fluid130/230to urge the drug122/222from the drug reservoir112/212via the outlet132/232, the fluid flow path may include a clamp or valve160/260configured to selectively allow and prevent fluid flow through the fluid flow path. The clamp or valve160/260may be variously configured and oriented without departing from the scope of the present disclosure, with the clamp or valve160/260being associated with the conduit134/234of the outlet132/232of the drug reservoir112/212, positioned at or adjacent to the opening of the outlet132,232in the illustrated embodiments. The clamp or valve160/260is configured to be moved from a closed condition (FIGS. 5 and 7) to an open condition (FIGS. 6 and 8), with fluid flow through the fluid flow path prevented when the clamp or valve160/260is in the closed condition (to retain the drug122/222within the reservoir112/212) and allowed when the clamp or valve160/260is in the open condition (to allow the drug122/222to be delivered from the reservoir112/212to a subject). The clamp or valve160/260may be configured to move only from the closed condition to the open condition or to move between the open and closed conditions.

The manner in which the clamp or valve160/260regulates fluid flow through the fluid flow path may vary, depending on the configuration of the fluid flow path and the position of the clamp or valve160/260. For example, in the illustrated embodiments, the clamp or valve160/260is associated with the conduit134/234, which may be configured as a flexible tube. In this case, the clamp or valve160/260may be configured as a pinch valve, which may squeeze the conduit134/234to close it, thereby preventing fluid flow through the conduit134/234. The pinch valve160/260may have arms162/262and164/264which are pivotally connected to move from the closed condition (in which they engage and compress the conduit134/234to prevent fluid flow therethrough) to the open condition (in which at least one of the arms applies less force to the conduit134/234to open to allow fluid to flow through the conduit134/234). In another embodiment in which the clamp or valve160/260is associated with a rigid tube or conduit, the clamp or valve160/260may be differently configured to selectively allow and prevent fluid flow through the fluid flow path. This may include the clamp or valve160/260being configured as, for example, a glove valve, ball valve, check valve, gate valve, tilting disk check valve, swing-check, or stop-check valve. It is also within the scope of the present disclosure for the clamp or valve160/260to be configured as an electromechanical valve, such as a solenoid valve.

In one embodiment, the clamp or valve160/260is configured to be moved from the closed condition to the open condition (optionally, between the open and closed conditions) by the controller118/218. This may be advantageous if the force applied by the pressurized fluid130/230does not change during a drug delivery routine, with the controller118/218causing the clamp or valve160/260to move from the closed condition to the open condition to allow fluid flow out of the drug reservoir112/212. Alternatively, the clamp or valve160/260may be configured to automatically move from the closed condition to the open condition upon an increase in pressure or force applied to the clamp or valve160/260by the drug122/222. This may be advantageous if the force applied by the pressurized fluid130/230may increase during a drug delivery routine, in which case the clamp or valve160/260may be configured as a check valve, being closed when the applied force is lower than a threshold amount and open when the applied force is greater than the threshold amount.

In any case, it will be seen that the pressurized fluid, drug reservoir, valve, and controller work in conjunction to convey the drug from the drug reservoir via the outlet and to the needle and patient during a drug delivery routine. The controller opens and closes the valve selectively (either directly or by causing a change in the force applied by the pressurized fluid) to selectively allow and prevent the drug from flowing out of the drug reservoir. Movement of the clamp or valve between open and closed conditions can be varied based on the selected drug delivery routine. For example, the clamp or valve can be moved to the open position and remain open during the duration of the drug delivery routine. The clamp or valve can also be moved back and forth between the open and closed positions during the drug delivery routine, with the change in position being based on any of a number of considerations. For example, the controller may move the clamp or valve from the open condition to the closed condition when a predetermined amount of the drug is conveyed from the drug reservoir or after a predetermined amount of time after moving the clamp or valve from the closed condition to the open condition. The change between the closed and open conditions can take place multiple times during a drug delivery routine, with the movement of the clamp or valve taking place in an irregular pattern or regular pattern, such as a duty cycle, depending on the needs of the routine.