Inserters, insertion methods, adaptions and junctions to allow dual drug delivery from a single body-worn patch pump

Abstract

The present invention provides inserters, insertion methods, adaptations and junctions that enable the subcutaneous delivery of two drugs from a single body-worn patch pump. The invention addresses challenges associated with dual drug delivery, including reducing the perceived pain of multiple cannula insertions and preventing unwanted mixing of drug combinations.

Description

Docket No. 85872-WOINSERTERS, INSERTION METHODS, ADAPTATIONS AND JUNCTIONS TO ALLOW DUAL DRUG DELIVERY FROM A SINGLE BODY-WORN PATCH PUMPCross-Reference to Related Applications

[0001] This application claims priority from US provisional patent application number 63 / 754,324. Such application is incorporated by reference herein.Statement Regarding Federally Sponsored Research or Development

[0002] This invention was made with government support under SBIR grant number R44DK137702 awarded by the National Institutes of Health (NIH). The government has certain rights in this invention.Field of the Invention

[0003] The present invention describes several inserters, insertion methods, adaptations and junctions that allow for the subcutaneous delivery of two drugs from a single body-worn patch pump.Background

[0004] The present invention is a component of a body-worn patch pumpthat delivers two drugs. Previous compact body-worn patch pumps have been unable to deliver independently two drugs.

[0005] There are various needs for subcutaneous delivery of two drugs from a single body-worn patch pump, including the reduction of insertion pain associated with the delivery of two drugs and the need to reduce or prevent mixing of some drug combinations.

[0006] Body-worn patch pumps must have a cannula through which the drug is delivered and an inserter, which places the drug-carrying cannula into the target delivery area, whether it is the subcutaneous space, intramuscular region, or other targeted dosing site. Inserters consist of three parts: the cannula(s), the insertion mechanism, which provides the insertion force, and the cannula carrier, whichtransfers the force from the inserter mechanism to the cannulas to complete the insertion. The insertion mechanism can be contained within the patch pump (an internal insertion mechanism). Or the insertion mechanism can be a separate device or source of force that is used and then removed from the wearable portion of the patch pump; this second type is referred to as an external insertion mechanism.

[0007] For patients using body-worn patch pumps for the subcutaneous injection of drugs, the perceived pain caused by cannula insertion is a significant consideration. If two drugs are being delivered subcutaneously through two separate cannulas, then there is the potential for feeling both insertions. The least painful way to deliver two drugs is to bring together the two inlet fluid paths into a single common outlet using a 2-to-l junction nearthe insertion site, so that only a single cannula need be inserted. Since there would be some drug mixing in the 2-to-l junction, not all drug combinations can be delivered using this method.

[0008] Drugs that cannot be pre-mixed must be delivered through two separate cannulas. In these cases, the spacing of the cannulas may be very important. Two- point differentiation studies have shown that humans are unable to feel the difference between simultaneous injections that are separated by 10 mm or less in distance (Koo, 2016). The perceived pain of two injections that are 10 mm or less in distance is similarto the perceived pain of a single injection. Several of the embodiments described herein make use of that distance range.

[0009] There are several drugs that are often administered in combination to treat illness and disorders. Common drug combinations are pain medications and antibiotics, cocktails for the treatment of HIV, and drugs to raise and lower blood sugarforthe treatment of Type 1 diabetes (T1D). For injectable drugs, some drug pairs can be mixed prior to injection without any effect on the efficacy of either drug, and some must be injected with adequate spacing to prevent mixing in the subcutaneous space. When considering close proximity injection of two drugs using a single body-worn patch pump, both chemical stability and PK / PD effects must be studied carefully to make sure that pre-injection or subcutaneous mixing is not an issue.

[0010] As an example of the variation in the effects of mixing drug pairs, insulin / glucagon and insulin / amylin are used. Both ofthese drug pairs can be used in combination to maintain euglycemia in people with T1D. Insulin is used to lower high blood sugar and glucagon is used to raise low blood sugar. Amylin can be used to slow gastric emptying, delaying a post-prandial glucose spike and allowing time for subcutaneously injected insulin to enter the bloodstream and become effective, reducing the post-prandial glucose spike. Studies have shown that there is no loss of efficacy due to mixing insulin and glucagon prior to injection or when co-injected at the same subcutaneous location (Teigen, 2024). Conversely, insulin and amylin cannot be mixed or injected at the same location in the subcutaneous space.

[0011] When delivering two drugs from a single body-worn pod, a variety of methods, apparatuses and inserters are needed.Summary of Invention

[0012] The present invention provides inserters, insertion methods, adaptations and junctions that enable the subcutaneous delivery of two drugs from a single body- worn patch pump. The invention addresses challenges associated with dual drug delivery, including reducing the perceived pain of multiple cannula insertions and preventing unwanted mixing of drug combinations.

[0013] In a first aspect, the invention provides methods for subcutaneous insertion of two cannulas using two single cannula inserters contained within a single body- worn patch pump. Each inserter maintains a separate fluid path for one of the two drugs being delivered. A single button or release mechanism simultaneously activates both inserters, allowing both cannulas to be inserted at the same time. In one configuration, the two inserters are mirror images of each other and are positioned so that the cannula tips are separated by 10 mm or less. Research has shown that simultaneous insertions separated by 10 mm or less are perceived as a single insertion, thereby reducing patient discomfort. This configuration is suitable for drug pairs that cannot be mixed prior to infusion but that can tolerate some mixing in the subcutaneous space. In another configuration, the twoinserters are identical but face opposite directions, resulting in cannula insertion sites that are separated by a greater distance, such as approximately 3 cm. This configuration is suitable for drug pairs that cannot be mixed either prior to insertion or within the subcutaneous space.

[0014] In a second aspect, the invention provides an adaptation to a single cannula inserter that enables the simultaneous insertion of two cannulas using a single insertion mechanism. The adaptation brings two separate fluid lines into the inserter body while maintaining complete separation of the fluid paths. An additional guide adaptation maintains precise spacing between the two cannulas, which may be positioned in very close proximity (such as 1 mm apart) or at greater distances (such as 5 mm apart) depending on the requirements of the drug pair being delivered. The guides also ensure that the cannulas are inserted with minimal lateral movement or vibration, thereby reducing patient discomfort.

[0015] In a third aspect, the invention provides 2-to-l junctions that bring two inlet fluid lines together into a single common outlet fluid line, enabling two drugs to be delivered through a single cannula. Because the two drugs may briefly contact each other in the junction, this aspect is suitable for drug pairs that do not negatively interact when mixed. The 2-to-l junctions incorporate passive valve systems that minimize the volume in which the two drugs may contact each other and that prevent backflow from one inlet fluid line to the other. Several valve configurations are provided, including a ball or cylinder valve that moves within a guide slot to close the inactive inlet path; a flexible gasket valve having flaps that are opened by fluid pressure from the active inlet while simultaneously closing the inactive inlet; a tube or plug valve using a deformable elastomeric element positioned between two coaxial inlet ports; and a resistive backflow barrier valve using geometry and flow characteristics to inhibit flow between the two inlets while promoting flow toward the common outlet. The 2-to-l junctions may be used with either internal or external insertion mechanisms.

[0016] In a fourth aspect, the invention provides a subcutaneous inserter having an external insertion mechanism. The inserter includes a support structure located within the body-worn patch pump, guide rails that hold a cannula carrier before,during, and after insertion, and a boss or other alignment feature that guides placement of an external insertion mechanism for transferring force to the cannula carrier. Steel cannulas connected to the fluid lines extend through slightly larger diameter soft cannulas. During insertion, an external force moves the cannula carrier along the guide rails, causing the sharp tips of the steel cannulas to pierce the skin and carry both the steel and soft cannulas into the subcutaneous space. The cannula carrier then returns along the guide rails, retracting the steel cannulas while gaskets retain the soft cannulas in the subcutaneous space. By locating the insertion mechanism externally rather than within the patch pump, the overall size of the wearable portion of the patch pump is reduced. This aspect may be configured to insert one, two, or more cannulas, and may be used in combination with the 2-to-l junctions described herein.

[0017] The various embodiments of the present invention may be combined and configured to accommodate the specific requirements of different drug pairs, including drug pairs that can be mixed, drug pairs that cannot be mixed prior to injection but can tolerate subcutaneous mixing, and drug pairs that cannot be mixed either before or after injection.Brief Description of Drawings

[0018] Figures la, lb and lc: Preferred Embodiment 1, Type a. Two inserters that are mirror images of each other.

[0019] Figure 2: Preferred Embodiment 1, Type b. Identical inserters that are facing opposite of each other.

[0020] Figures 3a and 3b: Preferred Embodiment 2. A dual cannula inserter using a single insertion mechanism for close proximity dosing.

[0021] Figure 4: A cross section of the adaptation used in Figure 3.

[0022] Figure 5: Preferred Embodiment 3, Type a. A 2-to-l junction that uses a ball valve.

[0023] Figures 6a and 6b: Preferred Embodiment 3, Type b. A 2-to-l junction that uses a flexible gasket valve.

[0024] Figure ?: Preferred Embodiment 3, Type c. A 2-to-l junction that uses a tube or plug valve.

[0025] Figure 8: Preferred Embodiment 3, Type d. A 2-to-l junction that uses a resistive backflow barrier valve.

[0026] Figures 9a and 9b: Preferred Embodiment 4. A dual cannula inserterthat uses an external insertion mechanism to generate the insertion force.Detailed Description of the Preferred Embodiments of the Invention

[0027] There are four main embodiments of the present invention.

[0028] Preferred Embodiment 1 is an adaptation to single cannula inserters in which the two fluid paths remain separate and two cannulas are inserted into the skin to allow for dual drug delivery from a single body-worn patch pump. In Preferred Embodiment 1, the internal insertion mechanism and cannula carrier are fully contained within the body-worn patch pump.

[0029] Preferred Embodiment 1 is an adaptation to single cannula inserters which includes two separate fluid paths that do not come together and two cannulas that are inserted into the subcutaneous space using two separate insertion mechanisms and two separate cannula carriers to allow for dual drug delivery from a single body-worn patch pump. These insertion mechanisms use compressed springs which are released upon pressing a button to release the cannula locking mechanism that holds the spring in a compressed state. The springs then generate the force needed to insert the cannulas into the subcutaneous space. Other methods of force generation including solenoids, electromagnets, human generated force, shape memory alloys, stepping motors, expanding gas amongst others are incorporated herein without explicit reference. Additionally, there are other methods of releasing the cannula locking mechanism for insertion besides pressing a button, including manual and electronic release mechanisms, which are also within the scope of the present invention. In the present invention for delivery of two drugs from a single body-worn patch pump, two cannula inserterscan be released simultaneously using a single button to reduce the perceived pain of two insertions.

[0030] In a Preferred Embodiment 1, Type a, the two single inserters are mirror images of each other and are affixed to each other or built into the same housing. Figure 1 shows drawings of Preferred Embodiment l.a. Two inserters (1 and 2) that are mirror images of each other allow the two fluid lines (3 and 4) to come in from opposites sides of each other. Cannula locking mechanisms (5 and 6) hold the springs in a compressed state, and a single button (7) releases both cannula locking mechanisms simultaneously. The tips of the two cannulas (8 and 9) are <10 mm apart so that the dual insertion is felt as a single insertion. Figure la has the housing removed to show the cannula locking mechanisms (5 and 6), and Figure lb shows the housing including a single button that releases both cannula locking mechanisms simultaneously. Figure lc is a side view, showing how the inserters sits in the patch pump. Note that two insertersfittightly within the patch pump to minimize the footprint of the patch pump.

[0031] The two fluid paths are completely separate throughout the patch pump and the cannula inserter. Each cannula is inserted into the subcutaneous space using its own spring to generate the force, and the separation of the cannulas is dictated in part by the diameter of the springs, as they cannot interfere with each other. In order to minimize the perceived pain of two insertions, the cannulas should be spaced <10 mm apart. A second pain reducing technique may be to angle the insertion mechanism and the two cannulas slightly toward each other such that they steady each other during insertion.

[0032] An additional aspect of the first preferred embodiment is a single button that allows both compressed springs to be released simultaneously. This can be achieved by altering the shape and / or orientation of the cannula locking mechanism that hold the two springs in place. The locking clips are positioned so that a single button will release both simultaneously. Another alternative would be an electronic mechanism that is designed to release both cannula locking mechanisms.

[0033] Preferred Embodiment l.a. is preferred for a drug pair that cannot be mixed prior to infusion but can experience some mixing in the subcutaneous space. Mixing in the subcutaneous space can be further minimized by a time delay between the delivery of alternate drugs. This time delay would allow the first drug to be absorbed into the body prior to delivery of the second drug.

[0034] In Preferred Embodiment 1, Type b, the two inserters are not made as mirror images of each other, instead they are exactly the same but are affixed facing opposite directions from each other, as shown in Figure 2. In preferred embodiment l.b., identical inserters (1 and 2) are facing opposite of each other, which allows the two fluid lines (3 and 4) to come in from opposite sides. A single button (7) releases both cannula locking mechanisms simultaneously. However, the tips of the cannulas (8 and 9) are now inserted approximately 3 cm apart from each other. This dual drug inserter is used for drugs that cannot be mixed either prior to insertion or subcutaneously.

[0035] The two insertions occur simultaneously from the press of a single button, and the two drugs are dispensed several centimeters away from each other so that subcutaneous mixing of the drugs is not possible, even though they can be administered at the same time or very closely in time. The drugs can be delivered as needed without concern for mixing in the patch pump, inserter, or in the subcutaneous space. In this embodiment, the patient may feel the two insertions separately, but perceived pain may be reduced by the balancing action of the inserters operating opposite directions. One advantage of this embodiment is that the cannulas are inserted at a maximum distance from each other to prevent mixing of the two drugs within the subcutaneous space while not increasing the size of the patch pump. It also requires very little alteration from an original singledrug insertion mechanism design.

[0036] Preferred Embodiment 2 is a dual-cannula inserter. A single insertion mechanism and cannula carrier is used to simultaneously insert two cannulas following the press of a button or other release of a locking mechanism. In this case, the force to insert both cannulas into the subcutaneous space is provided by a single spring or other actuator. Figure 3 shows two configurations of PreferredEmbodiment 2. An inserter (1) for a dual drug delivery system using a single insertion mechanism in a single housing for close proximity dosing. An adaptation (shown in Figure 4) allows the two fluid lines (3 and 4) to come in from opposite sides. In Figure 3a, the two cannulas (8 and 9) are in very close proximity to each other (1 mm) and in Figure 3b, the two cannulas (8 and 9) are further apart (5 mm). To maintain a set distance between the two cannulas, the inserter body is designed with guide adaptations to control the placement of the two cannulas with very high precision. The guide adaptations ensure that the cannulas are inserted directly into the subcutaneous space (or other targeted area) with minimal lateral movement or vibration, thereby minimizing patient discomfort. These guide adaptations also ensure that the cannulas are a specific distance from each other, so thatthere can be no unwanted mixing of drugs in the subcutaneous space, if that is desired.

[0037] In these configurations, the fluidic paths enter the cannula inserter housing from opposite sides and are activated by a button that activates a single release mechanism, although the fluidic paths do not need to enter through opposite sides. Each fluidic path is completely separate with no possibility for mixing the two drugs inside the cannula inserter.

[0038] Figure 4 shows the adaptation that allows the two fluid paths to come in from opposite sides of the inserter. A cross section of the adaptation (10) allows the two fluid lines (3 and 4) to come in from opposite sides, where they make a 90° turn and travel to the tips of the cannulas. The spacing between guide adaptations (11 and 12) determines the spacing between the cannula tips.

[0039] In this case, there is no consideration of interference between two springs, and the cannulas can be directly side by side or several mm apart, depending on the restrictions imposed by potential drug interactions and delivery profiles. In this embodiment, care must be taken so that the housing, insertion mechanism, and cannula carrier parts are strong enough to withstand the force of two simultaneous cannula insertions. Likewise, the spring must be strong enough to insert both cannulas reliably and speedily, to avoid any extra pain from a slow insertion. This adaptation is ideal for drugs that must be delivered individually invery accurate amounts, but that have no negative interaction in the event that they do come into contact with each other in the subcutaneous space. A similar adaptation could be designed to allow both of the fluid paths to come into the inserter body from one side if that allowed fora more compact drug delivery patch pump.

[0040] Preferred Embodiment 3 is a device used in concert with a single cannula inserter in which the two fluid paths come together in a 2-to-l junction in the body of the inserter. The two drugs being delivered by a single body-worn patch pump may mix briefly in the very small volumes prior to subcutaneous delivery. The 2- to-1 junction brings the two inlet fluid paths together into a single common outlet fluid path and is contained within the body of the cannula carrier so that two drugs can be delivered using a single cannula inserted under the skin. Any potential mixing or contact volume between the two drugs is very small compared to the doses being given. Additionally, the drugs will only contact each other during the transition from one drug to the other. As small volumes of the two drugs being delivered using a 2-to-l junction may mix briefly and at very small volumes prior to subcutaneous delivery, this invention is only applicable for drugs that do not negatively interfere with each other. The 2-to-l junction may incorporate various miniature passive valve systems that maintain the accuracy of delivery for each drug while ensuring minimal contact between the two drugs. The 2-to-l junction will not significantly increase the size of the patch pump. Miniaturization of passive valves is a significant challenge that is addressed in the designs outlined below.

[0041] Preferred Embodiment 3, Type a is a 2-to-l junction with ba ll / cy I inder valve.This 2-to-l junction uses a passive ball or cylinder valve that is placed in a guide slot so that two potential fluidic paths exist through the guide slot. The pressure of the moving fluid, the drug formulation that is currently being delivered, moves the ball or cylinder into a position that closes the inactive inlet paths and leaves the active inlet and the outlet open. During the transition state, the outlet is closed to both inlet paths so that the two fluid paths are always separated by thespherical or cylindrical valve. In the valves of embodiment 3. a., the two drugs cannot be delivered simultaneously.

[0042] In this design, the drugs would only mix in the case of switching the drug being delivered. The amount of the former drug being delivered out of the dead volume would be the volume of the outlet cannula.

[0043] Figure 5 shows preferred embodiment 3. a., which is a 2-to-l junction (13) that brings two inlet fluid lines (3 and 4) into a single common outlet (14) to the cannula. A guide slot (15) contains a stainless steel ball valve (16). In this drawing drug from fluid line (4) has pushed the ball valve (16) to cover fluid line 3, so that drug from fluid line 4 is delivered through the common cannula (14).

[0044] The embodiment shown in Figure 5 uses a 1 mm diameter stainless steel ball bearing as the valve mechanism. These are readily available and manufactured with very tight tolerances. The active incoming fluid line would provide the pressure to seat the ball against the inactive fluid line. In certain embodiments, the design fits within the housing of a single cannula inserter without significantly increasing the size.

[0045] Preferred Embodiment 3, Type b is a 2-to-l junction with a flexible gasket valve. This 2-to-l junction uses a passive valve that is an improved umbrella valve design. In this design, an elastomeric disk with a flap cut into it is placed against both of the microfluidic inlet ports. The flap is designed so that it has significant overlap with the valve housing around the fluidic inlet channel. A fluid entering the housing through the active fluid port will have sufficient pressure to push the flap open and spill into the valve housing, however, that same pressure will act to close the inactive fluidic port, pressing the flap against the housing wall, sealing it closed. The pressure is relieved, and fluid flow occurs, through the outlet port into the cannula extending into the patient.

[0046] The dead volume in this type of valve can be made very small but will have a dead volume largerthan justthe outlet cannula, as described in valve embodiment 3. a. In addition to the dead volume in the subcutaneously placed cannula, the interior of the valve chamber must have enough volume so that the flap can open,this area would be a potential mixing chamber forthe two drugs. Again, the drugs would only interact in the case when the drug being delivered has been switched.

[0047] Figure 6a shows preferred embodiment 3.b., which is 2-to-l junction (13) that brings two inlet fluid lines (3 and 4) into a single common outlet (14) to the cannula. There is a small valve housing (17) that empties into the common outlet (14). Each of the inlet fluid lines ends in a flexible gasket with a C-cut (18). Fluid from the active fluid line will push open the C-cut and allow flow into the valve housing (17) and out of the common outlet (14). Pressure from the operating fluid will close the C-cut on the inactive inlet port to prevent backflow.

[0048] One of the flexible gaskets is shown in Figure 6b. The two soft flexible gaskets are essentially disks with a "C" cut into them. The "C" acts as the flap described above. The length of the cut arc of the "C" along with the stiffness of the elastomer, plastic or other material used will determine the cracking pressure of this valve. Just like in embodiment 3. a, the incoming fluid would provide the pressure that would press open the "C" on the inlet valve forthat fluid and provide a force that would push to seal the "C" on the inactive inlet closed. The only outlet path for the fluid coming into the valve chamber would be through the subcutaneously inserted cannula. This design could easily fit within the housing of a single cannula inserter without significantly increasing the size.

[0049] Preferred Embodiment 3, Type c is a 2-to-l junction with tube or plug valve.This passive valve uses a single elastomeric plug situated between two co-axial inlet ports wherein the pressure from an incoming fluid deforms the elastomeric plug away from the inlet port and further increases the pressure on the other, inactive, inlet port further restricting flow into that port. The pressure in the valve chamber can only be relieved through the common outlet fluid path that leads directly to the subcutaneously inserted cannula.

[0050] In this design, the dead volume can be virtually zero outside of the length of the cannula extending from this valve to the subcutaneous space. This minimizes the dead volume of the 2-to-l junction. The "plug" that acts as the valve can be of a soft, easily deformable elastomer, with increasing stiffness of the elastomeric part increasing the cracking pressure of the valve. In addition to the stiffness orhardness of the elastomer, the effective thickness of the elastomer can be modified by changing the shape of the plug, further altering the force required to open the valve. For example, the plug can be solid, or it can have a hollow center like a tube, or any other grooves, pockets, or recess to lower the cracking pressure. Additionally, it can have harder or more dense materials bound inside of it to increase the cracking pressure, if desired.

[0051] Preferred embodiment 3.c. is shown in Figure 7. It is a 2-to-l junction (13) that brings two inlet fluid lines (3 and 4) into a single common outlet (14) to the cannula. The valve housing is filled with an elastomeric material (19). Fluid from the active fluid line will push aside the elastomeric material and allow flow into the valve housing and out of the common outlet (14).

[0052] In this embodiment, a solid plug of elastomeric material is placed between the two inlet ports. The pressure from the fluid coming in from either port would press the elastomer away from the port wall, creating a fluid path that would extend to the common outlet and the cannula. The force would also increase the pressure on the second, inactive, inlet port, sealing that port. In another embodiment (not shown), the plug is an elastomeric tube. In this embodiment, the pressure created by the incoming fluid presses against the wall of the tube, but the pressure may be reduced since the middle of the tube can collapse to open the valve. In either of these embodiments, the valve will return to its normally closed position under the elastomer's own resilience when fluid is not actively being pumped into the chamber.

[0053] Preferred Embodiment 3, Type d is a 2-to-l junction with a resistive backflow barrier valve. This 2-to-l junction brings the two inlet flow paths together in a formation that is designed to inhibit the flow from one inlet to the other inlet using a resistive backflow barrier(s) between the two inlets. Additionally, the area around the outlet to the cannula is shaped to promote flow into the cannula. Flow from one inlet to the other is further inhibited by the fluid pressure in each of the inlets. If needed, the fluid pressure within each inlet can be increased by placing a valve in each of the fluid lines upstream from the 2-to-l junction. This valve would remain closed in an inactive fluid inlet path.

[0054] Figure 8 shows preferred embodiment 3.d., which is a 2-to-l junction (13) that brings two inlet fluid lines (3 and 4) into a single common outlet (14) to the cannula. The dimensions and shape of each valve arm are designed to promote flow toward the common outlet. Additionally, a resistive backflow barrier (20) inhibits flow from one valve arm to the other. The overall shape of this 2-to-l junction resembles a Y formation.

[0055] The dimensions and shape of each inlet create a Y-formation that is designed to promote flow from each inlet to the common outlet and cannula. This design work can initially be conducted using flow simulation software and then optimized to the viscosity and flow characteristics of the two drugs. There are no moving parts in this embodiment of a 2-to-l junction.

[0056] The 2-to-l junctions in Preferred Embodiment 3 can be used with either internal (such as those in Preferred Embodiment 1 and 2) or external (such as Preferred Embodiment 4) insertion mechanisms

[0057] Preferred Embodiment 4 is a dual cannula inserter in which the insertion mechanism is separate from, and external, to the body-worn patch pump. By having the force to insert the two cannulas generated externally to the patch pump, the overall size of the patch pump is reduced. Even though the discussion of preferred embodiment 4 is focused on insertion of two cannulas, it could be designed to insert any number of one or more cannulas. Additionally, the insertion mechanism described in embodiment 4 can be used to insert soft or hard cannulas into the subcutaneous space. The external insertion mechanism can be a single use device or can be used multiple times to insert cannula for multiple patches.

[0058] One example of preferred embodiment 4 is shown in Figure 9. The subcutaneous cannula inserter consists of a support structure (21) that is located inside of a dual drug body-worn patch pump. The support structure (21) has guide rails (22) that hold the cannula carrier (23) in place before, during and after insertion. A boss (25) can be used to guide placement of the external insertion mechanism (not shown) to ensure that the force is effectively transferred to the cannula carrier (23). Other methods of aligning the parts, such as a recess, guide, or jig, can be used in place of the boss (25) shown in Figure 9. In this embodimentthe two inlet fluid lines (3 and 4) are attached to smaller diameter steel cannulas (8 and 9) that are angled through the cannula carrier (23). The steel cannulas run through slightly larger diameter soft cannulas (26 and 27) and end in a sharp point.

[0059] During insertion, the cannula carrier (23) is forced downward along the guide rails (22), and the sharp tips of the steel cannulas (8 and 9) pierce the skin. The external insertion mechanism forces both of the steel cannulas (8 and 9) and both of the soft cannulas (26 and 27) into the subcutaneous space. Then, the cannula carrier (23) returns back up the guide rails (22), pulling the steel cannulas (8 and 9) back up and leaving the soft cannulas (26 and 27) embedded in the subcutaneous space. The gaskets (28) ensure that the soft cannulas remain embedded in the subcutaneous space while the steel cannulas are retracted by the cannula carrier (23).

[0060] During drug delivery, fluid from either or both fluid lines (3 and 4) travels first through the steel cannulas (8 and 9), then through the soft cannulas (26 and 27) and then into the subcutaneous space.

[0061] Figure 9a shows the cannulas before insertion, and Figure 9b shows the cannulas after insertion. This embodiment can be used to insert two cannulas separately ora single cannula extending from a 2-to-l junction so that only a single cannula is inserted into the body, depending on the mixing prevention requirements of the two drugs in use.

Claims

CLAIMS:

1. A method for subcutaneous insertion of two cannulas, each comprising a cannula locking mechanism, for delivery of two drugs from a single body-worn patch pump, comprising the steps of:a. using two single cannula inserters, one for each of the drugs being delivered;b. placing the two inserters next to each other in the body-worn patch pump; c. using a button that simultaneously releases both cannula locking mechanisms; andd. subcutaneously inserting the cannulas at two insertion sites.

2. The method of claim l,furthercomprisingthestep offacingthetwo single cannula inserters in the same direction.

3. The method of claim l,furthercomprisingthestep offacingthetwo single cannula inserters in opposite directions.

4. The method of claim 1, further comprising the step of customizing the distance between the two insertion sites to reduce perceived pain during insertion.

5. The method of claim 1, further comprising the step of customizing the distance between the two insertion sites for the two drugs being delivered to prevent unwanted drug interactions.

6. The method of claim 1, further comprising the step of optimizing a timing of delivery of each drug.

7. The method of claim 1, wherein each of the cannulas comprise a cannula tip, and further comprising the step of using a guide to angle the cannula tips to minimize vibration.

8. Adaptations to a single cannula inserter that allows for subcutaneous insertion of two cannulas at two insertion sites for delivery of two drugs from a single body- worn patch pump, comprising:a. an internal adaptation to a single cannula inserter that brings two drug fluid lines into the single cannula inserter; andb. a guide adaptation that maintains a specific distance between the two insertion sites.

9. The adaptations of claim 8, further comprising a spring in the inserter, and wherein the spring in the inserter is made strong enough to insert two cannulas.

10. The adaptations of claim 8, wherein the two fluid lines enter from opposite sides of the inserter.

11. The adaptations of claim 8, wherein the two fluid lines enter from the same side of the inserter.

12. The adaptations of claim 8, wherein the distance between the two insertion sites is customized for the two drugs being delivered.

13. The adaptations of claim 8, wherein the adaptations are configured such that a timing of delivery of each drug is optimized.

14. The adaptations of claim 8, wherein each of the cannulas comprise a cannula tip, and wherein the cannula tips are angled to minimize vibration.

15. A 2-to-l junction for independent delivery of two drugs from a single body-worn patch pump, comprising:a. an adaptation that brings two inlet fluid lines into one outlet fluid line; and b. a valve positioned where the two inlet fluid lines converge.

16. The 2-to-l junction of claim 15, wherein the two inlet fluid lines come together at a set angle.

17. The 2-to-l junction of claim 15, wherein the valve prevents or minimizes mixing of the two drugs being delivered.

18. The 2-to-l junction of claim 15, wherein the valve moves or is moved to allow flow from one inlet fluid line to the outlet fluid line.

19. The 2-to-l junction of claim 15, wherein the valve prevents backflow from a first inlet fluid line to a second inlet fluid line.

20. The 2-to-l junction of claim 15, wherein the valve is passive.

21. The 2-to-l junction of claim 15, wherein the valve is a ball or cylinder valve.

22. The 2-to-l junction of claim 15, wherein the valve is a flexible gasket valve.

23. The 2-to-l junction of claim 15, wherein the valve is a tube or plug valve.

24. The 2-to-l junction of claim 15, wherein the valve is a resistive backflow barrier valve.

25. The 2-to-l junction of claim 15, wherein the outlet fluid line is inserted using an internal insertion mechanism.

26. The 2-to-l junction of claim 15, wherein the outlet fluid line is inserted using an external insertion mechanism.

27. A subcutaneous inserter for delivery of two drugs from a single body-worn patch pump, comprising:a. a support structure to stabilize the subcutaneous inserter inside of the body-worn patch pump;b. a cannula carrier mounted on guide rails in the support structure;c. a boss that transfers an external insertion force to move the cannula carrier down and then back up the guide rails;d. two stainless steel cannulas that are angled through the cannula carrier and connected to two fluid lines coming from the body-worn patch pump; e. two soft cannulas placed over the two stainless steel cannulas; and f. two gaskets to hold the two soft cannulas in the subcutaneous space after the two stainless steel cannulas are retracted.

28. The subcutaneous inserter of claim 1 modified for subcutaneous delivery of one drug.

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