Injection delivery device

Abstract

The present invention relates to an infusion delivery device comprising a reservoir configured to contain a liquid medicament, a dispensing member movably arranged within the reservoir for dispensing the liquid medicament from the reservoir through an outlet of the reservoir, an actuation member configured to move the dispensing member within the reservoir, and a controller configured to control the movement of the dispensing member within the reservoir by the actuation member, the controller being further configured to determine an occlusion preventing the dispensing of the liquid medicament from the reservoir, and configured to provide a control signal to the actuation member for moving the dispensing member in a reverse direction around a displacement distance upon determining the occlusion, the displacement distance being a model-based displacement distance to prevent overdosing or underdosing upon occlusion.

Description

[Technical field]

[0001] The present invention relates to an injection delivery device comprising a reservoir configured to contain a liquid medicament, a dispensing member movably arranged within the reservoir for dispensing the liquid medicament from the reservoir through an outlet of the reservoir, an actuation member configured to move the dispensing member within the reservoir, and a controller configured to control the movement of the dispensing member within the reservoir by the actuation member, wherein the controller is further configured to determine an obstruction preventing the dispensing of the liquid medicament from the reservoir, and upon determining the obstruction, is configured to provide a control signal to the actuation member to move the dispensing member in the reverse direction around a displacement distance. [Background technology]

[0002] The previously known infusion delivery devices are in fluid communication with a patient's body during use, whereby a liquid medicament preloaded in a reservoir of the infusion delivery device can be administered into the patient's body through an outlet from the reservoir. The liquid medicament is dispensed by the movement of a dispensing member in the reservoir by an actuation member, which is controlled by a controller of the infusion delivery device. Thus, the controller controls the amount of liquid medicament administered into the patient's body by controlling the movement of the displacement member with the aid of the actuation member.

[0003] Controlling the amount of drug injected into a patient's body is particularly important since the amount of drug is intrinsically related to a particular or desired medical purpose. Overdosing or underdosing, respectively, of liquid drugs can have serious adverse effects on the patient's health.

[0004] The administration of the liquid medicament may be partially or completely prevented by the blockage of the outlet. Until the determination of the blockage, the dispensing member is further advanced by the actuation member, thereby increasing the pressure in the reservoir. Upon the determination of the blockage, the controller of the previously known infusion delivery device is configured to provide a control signal to the actuation member to move the dispensing member in the reverse direction around the displacement distance. Nevertheless, since the pressure increase is unpredictable, there is a risk that the displacement distance does not meet the requirement to equalize the pressure in the reservoir. If the blockage is suddenly cleared, the pressure may not be reduced enough to reduce the risk of unintended overdosing. On the other hand, the displacement distance may be too large, resulting in a negative pressure in the reservoir. The liquid medicament intended to be administered to the patient may be drawn in the reverse direction, i.e., back into the reservoir, which may result in unintended underdosing as well as extraction of bodily fluids. Summary of the Invention [Problem to be solved by the invention]

[0005] It is therefore an object of the present invention to provide an infusion delivery device which avoids at least one of the problems associated with infusion delivery devices known from the prior art.In particular, it is an object of the present invention to provide an infusion delivery device which reduces the risk of overdosing and underdosing of liquid medicament administered to a patient upon determination of an obstruction. [Means for solving the problem]

[0006] At least one of the above objectives is achieved by providing subject matter disclosed in the claims and throughout the specification.

[0007] According to a first aspect, an injection delivery device comprises a reservoir configured to contain a liquid medicament, a dispensing member movably arranged in the reservoir for dispensing the liquid medicament from the reservoir through an outlet of the reservoir, an actuation member configured to move the dispensing member within the reservoir, and a controller configured to control movement of the dispensing member within the reservoir by the actuation member, wherein the controller is further configured to determine an occlusion preventing dispensing of the liquid medicament from the reservoir, and upon determining the occlusion, is configured to provide a control signal to the actuation member to move the dispensing member in the reverse direction around a displacement distance, the displacement distance being a model-based displacement distance.

[0008] An infusion delivery device, such as an insulin pump or drug pump, comprises a reservoir configured to hold a liquid medicament to be administered into a patient's body during use of the infusion delivery device. A dispensing member is movably disposed within the reservoir, such that movement of the dispensing member can dispense the liquid medicament. When actuated by an actuation member, the dispensing member forces the liquid medicament out of the reservoir through an outlet of the reservoir and further into the patient's body. Thus, by controlling the movement of the dispensing member, the amount of liquid medicament dispensed from the reservoir is also controlled. The movement of the dispensing member is controlled by controlling the actuation member by a controller.

[0009] The controller is further configured to determine an occlusion, i.e., an unplanned complete or partial closure that prevents the flow of liquid medicament through the outlet. In the sense of the present invention, the term outlet encompasses the reservoir opening as well as any tube or fluid pathway in fluid communication with the reservoir opening, including any cannula, needle, etc. for conveying liquid medicament from the reservoir into the patient's body during use of the infusion delivery device.

[0010] For example, the controller may be configured to determine an occlusion by monitoring at least one parameter indicative of an amount of torque or force or energy required by the actuation member to advance the dispensing member within the reservoir to dispense the liquid medicament. Alternatively or additionally, the controller may be configured to receive notification by an auxiliary sensor or detector or device that an occlusion has occurred.

[0011] The controller is further configured to provide a control signal to the actuation member upon determining the blockage, to move the dispensing member in a reverse direction around the displacement distance. In the sense of the present invention, a reverse direction is a direction opposite to the direction required to dispense the liquid medicament from the reservoir through the outlet. By moving in a reverse direction around the displacement distance, the accumulated pressure in the reservoir is reduced by the movement of the dispensing member intended to dispense the liquid medicament from the reservoir through the at least partially clogged outlet.

[0012] However, the displacement distance is a model-based displacement distance so that the dispensing member does not move too far in the reverse direction, i.e., an order of magnitude of a shorter or longer displacement distance than required to equalize the pressure in the reservoir. Thus, a control signal to the actuation member to move the dispensing member in the reverse direction around the displacement distance at the time of determining the occlusion is a control signal to the actuation member to move the dispensing member in the reverse direction the model-based displacement distance at the time of determining the occlusion. This avoids the creation of unintended negative pressure in the reservoir, which could otherwise re-aspirate liquid medicament into the reservoir intended to be administered into the patient's body.

[0013] According to one embodiment, the model-based displacement distance takes into account a parameter indicative of the current position of the dispensing member in the reservoir and / or a parameter indicative of the temperature of the reservoir and / or a parameter indicative of the temperature of the drug in the reservoir. The current position of the dispensing member indicates the amount or volume of the drug in the reservoir, respectively, and thus also the percentage of the reservoir in contact with the drug. The size of the contact area indicates the deformability of the reservoir as well as the force exerted by the drug on the reservoir due to a given pressure in the reservoir.

[0014] As an example, in one embodiment, if the current position of the dispensing member in the reservoir is closer to the outlet, the model-based displacement distance is smaller than if the current position of the dispensing member in the reservoir is further from the outlet. The accuracy of transferring the parameter indicative of the current position of the dispensing member to the model-based displacement distance can be increased or decreased by the resolution of the underlying metric. Each position of the dispensing member can be assigned to a different model-based displacement distance. On the other hand, each position of the dispensing member within a predetermined range can be assigned to the same model-based displacement distance. For example, if the current position of the dispensing member is within a first division of the maximum displacement distance of the dispensing member adjacent to the outlet of the reservoir, a first model-based displacement distance can be used. If the current position of the dispensing member is within a second division of the maximum displacement distance following the first division of the maximum displacement distance, a second model-based displacement distance can be used. If the current position of the next dispensing member is within a third division of the maximum displacement distance following the second division opposite the first division, a third model-based displacement distance of the dispensing member can be used. The first division, the second division, and the third division may be equal, accounting for one third of the maximum displacement distance. Alternatively, the size and number of the divisions may be set based on a model of the reservoir and plunger system.

[0015] Similarly, the temperature of the reservoir as well as the temperature of the medicament within the reservoir affect the pressure that may build up by advancing the dispensing member further within the reservoir. A model-based displacement distance taking into account a parameter indicative of the actual position of the dispensing member within the reservoir and / or a parameter indicative of the temperature of the reservoir and / or a parameter indicative of the temperature of the liquid medicament within the reservoir is beneficial to move the dispensing member within the reservoir around a displacement distance suitable to equalize the pressure within the reservoir in light of the current state of the reservoir and the position of the dispensing member within the reservoir.

[0016] According to one embodiment, the dispensing member is a plunger or a membrane. The plunger is movably arranged in the reservoir by an actuating member. By moving the plunger in a direction towards the outlet of the reservoir, the liquid agent contained in the volume between the plunger and the outlet is forced through the outlet towards the outlet. The distance the plunger advances in the reservoir indicates the amount of liquid agent dispensed from the reservoir. The membrane is also movably arranged in the reservoir, where "moving" can also mean that at least a part of the membrane is deformed to deflect towards the outlet in order to dispense the liquid agent from the reservoir. Similarly, a movement in the opposite direction corresponds to a deflection of at least a part of the membrane in a direction away from the outlet. By way of example, the actuating member for moving the membrane may be a hydraulic medium acting on the membrane.

[0017] According to one embodiment, the actuating member comprises a stepper motor, and the model-based displacement distance takes into account the missing steps per train and / or the motor current for the stepper motor. The stepper motor converts the current into a rotation, which is further converted by a gearbox into a longitudinal displacement of the dispensing member in the reservoir. Each electric pulse rotates the stepper motor one step. A train is a series of steps corresponding to a standard drive pattern of the stepper motor. However, the average number of missing steps, i.e. electric pulses that do not rotate the motor one step, is indicative of the reaction forces exerted on the dispensing member. Blockages result in higher reaction forces and thus increase the number of missing steps per drive train. Furthermore, some electric pulses are used up for stabilization and initial loading of components of the reservoir-dispensing member system, e.g. gaskets, O-rings, fittings, couplings, etc., rather than rotating the motor one step. Similarly, the electric motor current is indicative of the reaction forces exerted by the movement of the dispensing member. The average number of missing steps per train for the stepper motor and / or the motor current can be used to adapt a model-based displacement distance to level out the pressure in the reservoir in light of the actual condition of the reservoir and the position of the dispensing member within the reservoir.

[0018] In one embodiment, the actuating member of the injection delivery device is a motor and the displacement distance additionally or alternatively varies based on the motor current.

[0019] In one embodiment, the model-based displacement distance takes into account a parameter indicative of the pressure exerted by the liquid medicament in the reservoir on the dispensing member. The pressure in the reservoir exerted on the dispensing member may be determined directly or indirectly by a sensor or detector, such as, for example, a pressure sensor or a force sensor. The determination of the pressure exerted by the liquid medicament in the reservoir on the dispensing member may be used to determine a model-based displacement distance for equalizing the pressure in the reservoir. Thus, when determining a model-based displacement distance for controlling the actuation member to move the dispensing member in the reservoir to equalize the pressure in the reservoir, a parameter indicative of the pressure exerted by the liquid medicament in the reservoir on the dispensing member may be taken into account, thereby preventing overdosing or underdosing, respectively.

[0020] According to one embodiment, the model-based displacement distance takes into account a parameter indicative of the compressibility of the liquid agent in the reservoir and / or a parameter indicative of the compressibility of the reservoir, which influences the pressure that builds up in the reservoir when moving the dispensing member in the reservoir, especially in case of a blockage that prevents the flow of the liquid agent from the reservoir. Taking into account a parameter indicative of the compressibility of the liquid agent in the reservoir helps to adapt the model-based displacement distance to equalize the pressure in the reservoir when a blockage occurs.

[0021] In one embodiment, the model-based displacement distance is provided by a look-up table. Providing the model-based displacement distance reduces the processing power required by the controller to determine the respective model-based displacement distance required to equalize the pressure in the reservoir in light of the respective conditions of the reservoir and the position of the dispensing member. The model-based displacement distance can also be provided by a combination of a look-up table and a formula taking into account at least one input parameter. For example, the input parameter can be a sensor reading or a detector reading.

[0022] The present invention further relates to an infusion delivery device comprising a reservoir configured to contain a liquid medicament, a dispensing member movably arranged in the reservoir for dispensing the liquid medicament from the reservoir through an outlet of the reservoir, an actuation member configured to move the dispensing member within the reservoir, and a controller configured to control the movement of the dispensing member within the reservoir by the actuation member, The controller is further configured to determine an occlusion preventing dispensing of the liquid medicament from the reservoir, and upon determining the occlusion, is configured to provide a control signal to the actuation member to move the dispensing member in a reverse direction about a displacement distance, the displacement distance being: a parameter indicating the current position of the dosing element in the reservoir, and / or A parameter indicating the temperature of the reservoir, and / or A parameter indicating the temperature of the drug in the reservoir, and / or a parameter indicative of the pressure exerted on the dispensing member by the liquid medicament in the reservoir, and / or A parameter indicative of the compressibility of the liquid drug in the reservoir, and / or a parameter indicative of compressibility of the reservoir.

[0023] In one embodiment, the actuating member of the injection delivery device is a stepper motor, and the displacement distance additionally or alternatively varies based on the average number of missed steps per train for the stepper motor and / or the motor current.

[0024] In one embodiment, the actuating member of the injection delivery device is a motor and the displacement distance additionally or alternatively varies based on the motor current.

[0025] The invention further relates to a method for controlling an infusion delivery device comprising a reservoir configured to contain a liquid medicament, a dispensing member movably arranged in the reservoir for dispensing the liquid medicament from the reservoir through an outlet of the reservoir, and an actuation member configured to control movement of the dispensing member in the reservoir by the actuation member, the method comprising: determining, by the controller, a blockage of the outlet that prevents dispensing of the liquid medicament from the reservoir; upon determining an obstruction, providing a control signal by the controller to the actuation member to move the dispensing member in a reverse direction a displacement distance; Upon determining an occlusion, providing a control signal by the controller to the actuation member to move the dispensing member backward a displacement distance includes determining a model-based displacement distance as the displacement distance.

[0026] The controller controls the actuation member to move the dispensing member in the reservoir either in a direction to administer the liquid drug from the outlet into the patient's body or in the opposite or reverse direction. Upon determining an occlusion, the controller helps to prevent over- or under-administration of liquid drug during an occlusion as well as extraction of bodily fluids by providing a control signal to the actuation member to move the dispensing member in the reverse direction by a model-based displacement distance. The model-based displacement varies based on one or more parameters indicative of a current state of the infusion delivery device, in particular the current state of the reservoir and the dispensing member. The current state of the reservoir and the dispensing member with respect to the pressure caused thereby in the reservoir may be influenced by various parameters such as, for example, a parameter indicative of the temperature of the reservoir, and / or a parameter indicative of the temperature of the reservoir, and / or a parameter indicative of the temperature of the drug in the reservoir, and / or a parameter indicative of the pressure exerted on the dispensing member by the liquid drug in the reservoir, and / or a parameter indicative of the compressibility of the liquid drug in the reservoir, and / or a parameter indicative of the compressibility of the reservoir. Thus, in one embodiment, upon determining an occlusion, providing a control signal to the actuation member to move the dispensing member in the reverse direction a displacement distance comprises: a parameter indicating the current position of the dosing element in the reservoir, and / or A parameter indicating the temperature of the reservoir, and / or A parameter indicating the temperature of the drug in the reservoir, and / or a parameter indicative of the pressure exerted on the dispensing member by the liquid medicament in the reservoir, and / or A parameter indicative of the compressibility of the liquid drug in the reservoir, and / or a parameter indicative of a compressibility of the reservoir.

[0027] As previously mentioned, the actuating member of the infusion delivery device may be a motor or a stepper motor, and additionally or alternatively, the current state of the reservoir and the dispensing member with respect to the pressure caused thereby in the reservoir may be influenced by an average number of missing steps per drive and / or a motor current for the stepper motor. Thus, in one embodiment, upon determining an occlusion, providing a control signal to the actuating member to move the dispensing member in the reverse direction a displacement distance includes determining a model-based displacement distance based on one or more of the average number of missing steps per train and / or the motor current for the stepper motor.

[0028] The model-based displacement distance may be based on one or more of the aforementioned parameters, as outlined above with respect to the injection delivery device according to the present invention.

[0029] As discussed above and in the detailed description of the embodiments and claims that follow, reference is made to an infusion delivery device, and the described features thereof are applicable to the method of controlling the infusion delivery device, and vice versa.

[0030] Further advantages, features and technical effects of the present invention will be apparent from the following description of the embodiments and the accompanying drawings. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 shows a schematic diagram of an insulin delivery device according to one embodiment of the present invention. [Diagram 2] 2 shows a schematic flow chart of a method for controlling an infusion delivery device according to an embodiment of the present invention. [Diagram 3] 13 illustrates an example pressure gradient when considering a model-based displacement distance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] FIG. 1 shows a schematic diagram of an insulin delivery device 1 according to an embodiment of the present invention. The insulin delivery device 1 comprises a reservoir 2 configured to hold a liquid medication. Furthermore, the insulin delivery device 1 comprises a dispensing member 3 movably arranged in the reservoir 2. Here, by way of example, the dispensing member 3 is a plunger. The dispensing member 3 is moved in the reservoir 2 by an actuation member 5 controlled by a controller 6. The controller 6 is configured to provide a control signal to the actuation member 5 to move the dispensing member 3. In use, moving the dispensing member 3 by the actuation member 5 in a direction towards the outlet 4 of the reservoir causes dispensing of the liquid medication from the reservoir 2 via the outlet 4 into the patient's body.

[0033] The controller 6 is further configured to determine an occlusion that may partially or completely prevent the flow of the liquid drug from the reservoir 2 through the outlet 4 into the patient's body. To avoid causing overdosing or underdosing upon an occlusion, the controller is further configured to provide a control signal to the actuation member 5 to move the dispensing member 3 in the reverse direction 7 by a displacement distance. The displacement distance is a model-based displacement distance 8 determined by the controller 6 based on parameters indicative of the state of the reservoir 2 and the dispensing member 3. Depending on the state of the reservoir 2 and the dispensing member 3, e.g. the position of the dispensing member 3 within the reservoir 2, the model-based displacement distance 8 varies to equalize the pressure within the reservoir 2.

[0034] Fig. 2 shows a schematic flow chart of a method for controlling an infusion delivery device 1 according to an embodiment of the present invention. The infusion delivery device 1 may be configured as shown in Fig. 1. Starting at step S1, an occlusion preventing dispensing of a liquid medicament from a reservoir 2 of the infusion delivery device 1 is determined by a controller of the infusion delivery device 1. Upon determining the occlusion, in step S2, the controller determines a model-based displacement distance 8 for moving the dispensing member 3 in a reverse direction 7 with the aid of the actuating member 4 so as to equalize the pressure in the reservoir 2 as desired. According to step S3, the model-based displacement distance 8 is provided by the controller 6 to the actuating member 4 as part of a control signal for moving the dispensing member 3 in a reverse direction by the actuating member 5.

[0035] FIG. 3 shows the current position X of the dispensing member 3 in the reservoir 2. plu 3 shows an example pressure gradient that may be used to determine a model-based displacement distance 8 based on the pressure in the reservoir 2, P occl (pressure at occlusion) to pressure P op (normal operating pressure). As an example, the model-based displacement distance 8''' is smaller when the dispensing member 3 is located in the last 1 / 3 I3 of the reservoir 2 close to the outlet 4 than the model-based displacement distance 8'' when the dispensing member 3 is located in the second 1 / 3 I2 of the reservoir 2 close to the outlet 4. The model-based displacement distance 8' is smaller when the dispensing member 3 is located in the first 1 / 3 I1 of the reservoir 2 far from the outlet 4 than the model-based displacement 8 when the dispensing member 3 is located in the second 1 / 3 I2 of the reservoir 2 close to the outlet 4. [Explanation of symbols]

[0036] 1 Infusion delivery device 2 Reservoir 3 Dispensing parts 4 exit 5. Operating member 6 Controller 7 Reverse direction 8,8',8”,8'' model-based displacement distance 9 Dispensing member rod S1 Obstruction Determination S2 Model-based Displacement Distance Determination S3 Provides a control signal to the actuating member Interval next to I3 exit I2 The third interval, the interval next to I3 I1 is the next interval to the second interval I2, farther from the exit P occl. Pressure in the reservoir when blocked P op Pressure in the reservoir during normal operation X plu Position of the plunger in the reservoir

Claims

1. An injection delivery device (1), comprising: a reservoir (2) configured to contain a liquid medicament; a dispensing member (3) movably arranged within said reservoir (2) for dispensing a liquid medicament from said reservoir (2) through an outlet (4) of said reservoir (2); an actuation member (5) configured to move the dispensing member (3) within the reservoir (2); a controller (6) configured to control the movement of the dispensing member (3) in the reservoir (2) by the actuation member (5), the controller (6) is further configured to determine an occlusion preventing the dispensing of liquid medicament from the reservoir (2) and, upon determining the occlusion, to provide a control signal to the actuation member (5) to move the dispensing member (3) in a reverse direction (7) about a displacement distance (8); An injection delivery device (1), characterized in that said displacement distance (8) is a model-based displacement distance (8).

2. The injection delivery device (1) of claim 1, characterized in that the model-based displacement distance (8) takes into account a parameter indicative of a current position of the dispensing member (3) in the reservoir (2), and / or a parameter indicative of a temperature of the reservoir (2), and / or a parameter indicative of a temperature of the liquid drug in the reservoir (2).

3. The infusion delivery device (1) according to claim 1 or 2, characterized in that the actuating member (5) comprises a stepper motor and the model-based displacement distance (8) takes into account an average number of missed steps per train for the stepper motor and / or a motor current.

4. An injection delivery device (1) according to any one of claims 1 to 3, characterized in that the model-based displacement distance (8) takes into account a parameter indicative of the pressure exerted by the liquid medicament in the reservoir (2) on the dispensing member (3).

5. An injection delivery device (1) according to any one of claims 1 to 4, characterized in that the model-based displacement distance (8) takes into account a parameter indicative of compressibility of the liquid medicament in the reservoir (2).

6. Infusion delivery device (1) according to any one of claims 1 to 5, characterized in that the model-based displacement distance (8) is provided by a look-up table.

7. A method for controlling an injection delivery device (1), said injection delivery device (1) comprising a reservoir (2) configured to contain a liquid medicament, a dispensing member (3) movably arranged in said reservoir (2) for dispensing the liquid medicament from said reservoir (2) through an outlet (4) of said reservoir (2), and an actuation member (5) configured to control the movement of said dispensing member (3) in said reservoir (2) by said actuation member (5), The method further comprising: - determining by a controller (6) a blockage of the outlet (4) that prevents the dispensing of the liquid medicament from the reservoir (2); - upon determining a blockage, providing a control signal by said controller (6) to said actuating member (5) to move said dispensing member (3) in a reverse direction (7) by a displacement distance; Upon determining an occlusion, providing a control signal by the controller (6) to the actuating member (5) to move the dispensing member (3) in a reverse direction (7) by a displacement distance, the step including determining a model-based displacement distance (8) as the displacement distance.

13. A method for controlling an infusion delivery device (1), comprising:

8. determining the model-based displacement distance (8), a parameter indicative of the current position of the dispensing member (3) in the reservoir (2), and / or a parameter indicative of the temperature of said reservoir (2), and / or a parameter indicative of the temperature of the liquid medicament in the reservoir (2), and / or a parameter indicative of the pressure exerted on the dispensing member (3) by the liquid medicament in the reservoir (2), and / or a parameter indicative of the compressibility of the liquid medicament in the reservoir (2), and / or a parameter indicative of the compressibility of said reservoir (2), 8. The method for controlling an infusion delivery device (1) according to claim 7, characterized in that it is based on one or more of the following:

9. the actuating member (5) being a stepper motor, the step of determining the model-based displacement distance (8) comprising: the average number of missed steps per train for the stepper motor; and / or Motor current, 9. A method for controlling an infusion delivery device (1) according to claim 7 or 8, characterized in that it is based on one or more of the following:

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