Medical injector for on-body mounting with flow detecting

Abstract

In one aspect, a medical injector is provided for mounting onto the skin of a user for administering a dose of liquid drug to the user, the medical injector including: a body containing a reservoir of the liquid drug; a cannula for insertion into the skin of the user; a conduit for fluidically connecting the body and the cannula to allow the liquid drug to be conveyed to the cannula, wherein the conduit includes a tubular metallic section; a temperature sensor for measuring the temperature of the metallic section; and, a CPU for collecting periodic temperature measurements from the temperature sensor to evaluate change in temperature of the metallic section over time. Advantageously, the subject invention allows for a non-invasive mode of detecting drug flow in an on-body medical injector.

Description

MEDICAL INJECTOR FOR ON-BODY MOUNTING WITH FLOW DETECTINGFIELD OF THE INVENTION

[0001] The subject invention is directed to on-body medical injectors, particularly on-body injectors with flow detection.BACKGROUND OF THE INVENTION

[0002] On-body medical injectors are known in the prior art. Typically, these medical injectors include a body, housing a reservoir of injectable drug. The body includes an adhesive pad for adhering to a user’s skin at a target site (e.g., the abdomen or side of the user). The body further includes a switch which causes actuation of the injector once mounted. The actuation may cause a cannula to be auto-inserted into the patient in preparation for the injection. With the cannula inserted into the patient, drug is delivered by an automated system, such as being urged from the reservoir using a motor-driven plunger.

[0003] On-body medical injectors are primarily intended for in-home use. The cannula is typically hidden before use to ease anxiety. In addition, since a medical professional may not be present, efforts are made to best ensure proper operation. On-body injectors typically have high volume amounts, greater than which is deliverable by a standard syringe or the like. Thus, drug delivery is prolonged to allow the user’s body to accept the drug at a manageable rate. Full and proper delivery of drug is critical. Issues may arise since the body of the injector is typically opaque not allowing for visual confirmation of proper needle insertion and drug flow.SUMMARY OF THE INVENTION

[0004] In one aspect of the subject application, a medical injector is provided for mounting onto the skin of a user for administering a dose of liquid drug to the user, the medical injector including: a body containing a reservoir of the liquid drug; a cannula for insertion into the skin of the user; a conduit for fluidically connecting the body and the cannula to allow the liquid drug to be conveyed to the cannula, wherein the conduit includes a tubular metallic section; a temperature sensor for measuring the temperature of the metallic section; and, a CPU for collecting periodic temperature measurements from the temperature sensor to evaluate change in temperature of the metallic section over time.

[0005] In a further aspect of the subject application, a medical injector is provided for mounting onto the skin of a user for administering a dose of liquid drug to the user, the medical injector including: a body containing a reservoir of the liquid drug; a cannula for insertion into the skin of the user; a conduit for fluidically connecting the body and the cannula to allow the liquid drug to be conveyed to the cannula, wherein the conduit includes a tubular metallic section; an electric heating element configured to generate and apply heat to the metallic section; a temperature sensor, insulated from the heating element, for measuring the temperature of the metallic section; and, a CPU for collecting periodic temperature measurements from the temperature sensor to evaluate change in temperature of the metallic section over time.

[0006] Advantageously, the subject invention allows for a non-invasive mode of detecting drug flow in an on-body medical injector.

[0007] These and other features of the subject invention will be better understood through a study of the following detailed description and accompanying drawings.BRIEF DESCRIPTION OF THE FIGURES

[0008] Figures 1-2 depict an on-body medical injector useable with the subject invention;

[0009] Figure 3 depicts schematically an arrangement for detecting flow of liquid drug in an on-body medical injector in accordance with the subject invention;

[0010] Figure 4 is a graph showing temperature measurements by an arrangement consistent with Figure 3 collected over time;

[0011] Figure 5 is the arrangement of Figure 3 modified with an additional temperature sensor for contacting with, and measuring the temperature of, the skin of the user; and,

[0012] Figure 6 is a graph showing temperature measurements by the additional temperature sensor of Figure 5 collected over time.DETAILED DESCRIPTION OF THE INVENTION

[0013] With reference to the Figures, a medical injector is shown and generally designated with the reference number 10. The medical injector 10 is an on-body medical injector having a body 12 and a cannula 14 for inserting into the skin of a user for drug delivery. As shown in Figure 1, the cannula 14 may be provided as separate, and spaced from, the body 12. This allows for separate mounting of the body 12 and the cannula 14 to the skin of a user. A conduit 16 is provided for fluidically connecting the body 12 and the cannula 14.

[0014] The body 12 includes a reservoir 18 of liquid drug 20 to be delivered by the medical injector 10 to the user. The reservoir 18 may be in any form capable of accommodating the liquid drug 20, including, but not being limited to, a vial, a barrel, a sealed tube, a capsule, a blister pack, a thermo formed body (e.g., a sealed clamshell package), and so forth. The reservoir 18 may be rigid or collapsible.

[0015] The conduit 16 is arranged to convey the liquid drug 20 from the reservoir 18 and to the cannula 14. Any mode of urging the liquid drug 20 from the reservoir 18 may be utilized including, but not limited to, an advanceable plunger, compression, suction, and so forth.

[0016] The cannula 14 may be mounted to a hub 22. As shown in Figure 2, the hub 22 may be provided with a base layer 24, having adhesive 25 on an exposed face thereof, for mounting to the skin of the user. The hub 14 may be formed of polymeric material, such as thermoplastic material. The hub 22 may also include any actuatable arrangement for auto- inserting the cannula 14 into the skin of the user. The arrangement may utilize spring force, or other driving force, for urging the cannula 14 from an initial hidden state, as shownschematically in Figure 1 , to a use state protruding from the hub 22 where it is inserted into the skin of the user.

[0017] Alternatively, the cannula 14 may be configured for manual insertion into the skin of the user, e.g., being in the form of a butterfly needle or the like.

[0018] Further, alternatively, the cannula 14, along with the hub 22, may be located within the body 12. With this arrangement, the medical injector 10 would be one component for mounting to the skin of the user, as opposed to separately mounting the body 12 and the cannula 14 (the hub 22 if utilized) to the skin of the user. Here, the cannula 14 may be also configured to be auto-inserted into the skin of the patient, e.g., in response to a driving force (e.g., spring force). The hub 22 may be a support for the cannula 14 and need not be adhered to the patient’s skin, particularly where the cannula 14 is located within the body 12.

[0019] The conduit 16 may be flexible, e.g., formed of flexible polymeric and / or elastomeric material. This allows the conduit 16 to be displaced or deformed in response to movement of the medical injector 10 during transportation, storage, and preparation for injection. It is possible to form the conduit 16 of rigid material (e.g., metal, rigid plastic, etc.), but this is less preferred. The conduit 16 may be formed of polymeric and / or elastomeric materials, including, but not limited to medical grade polyvinylchloride (PVC), polyurethane, or equivalent. The conduit 16 is tubular with a lumen 26 defined therethrough for passage of the liquid drug 20.

[0020] The subject invention is provided with an arrangement for detecting flow of liquid drug through the conduit 16. The detection is not a form of measurement in that a flow rate is determined. Rather, the subject invention is directed to determining whether a flow through the conduit 16 in fact exists. Simplistically stated, the subject invention provides a binary indication of flow in identifying whether there is or is not flow. The grade or rate of flow is not determined. This avoids the complexity of flow-rate measuring arrangements, which utilize pressure drops (e.g., a venturi), in-line displaceable elements (e.g., impellers), and so forth.

[0021] It is additionally noted that the subject invention utilizes a non-invasive mode of determining flow. In this manner, the flow is fully contained within the conduit 16 without any extraneous elements coming into direct contact with the liquid drug 20. This maintains sterility.

[0022] In one arrangement, a tubular metallic section 28 may be included with the conduit 16. Preferably, the metallic section 28 has an inner lumen 30 with a generally constant crosssection. In addition, it is preferred that the cross-section of the lumen 30 match the crosssection of the lumen 26 so that the metallic section 28 does not create resistance, or other detrimental effect, on flow through the lumen 26. The metallic section 28 may be located along the conduit 16 so that non-metallic portions of the conduit 16 are located on both sides of the metallic section 28. A portion of the conduit 16 may be located within, or be defined by, the hub 22, particularly a portion of the conduit 16 downstream of the metallic section 28. It is further preferred that the outer diameter of the metallic section 28 match the outer diameter ofthe conduit 16 so that a single profile is provided along the full length of the conduit 16. The metallic section 28 may be located externally of the body 12 (e.g., between the body 12 and the hub 22) or within the body 12 (e.g., if the cannula is located within the body 12).

[0023] The metallic section 28 may be joined to adjoining portions of the conduit 16 using any technique which allows for joining of the elements with liquid-tight seals being defined. Fusion (e.g., metal / plastic fusion) and / or adhesion may be utilized.

[0024] As shown in Figure 3, a temperature sensor 32 is positioned for measuring temperature of the metallic section 28. The temperature sensor 32 may take temperature readings of the outer surface of the metallic section 28. The temperature sensor 32 is preferably an electrical element providing a voltage or current output representing a temperature reading. The temperature sensor 32 may be one or more of: thermistor; thermocouple; semiconductorbased temperature sensor; resistance temperature detector (RTD); and, infrared (IR) temperature sensor.

[0025] The temperature sensor 32 takes periodic readings, starting with at least one initial baseline reading prior to actuation of flow of the liquid drug 20. The initial baseline reading provides a temperature indicative of no flow through the conduit 16. With actuation, flow should be initiated through the conduit 16. As a result of the liquid drug 20 moving through the conduit 16, and particularly the metallic section 28, the liquid drug 20 causes removal of thermal energy as it flows through the metallic section 28, thereby causing a drop in temperature. A computer processing unit (CPU) 34 is provided, which is electrically coupled to the temperature sensor 32, and which collects the temperature measurements conducted by the temperature sensor 32. With the temperature sensor 32 taking periodic readings over time, a temperature versus time relationship may be evaluated, as shown in Figure 4. For example, as shown between T = 60 and T = 180 in Figure 4, there is a steady decline in temperature. This is indicative of thermal energy being removed by flowing liquid drug 20. It is possible for the temperature to plateau representing a flow state where the temperature reaches a steady state. An increase in temperature, however, may be indicative of a lack of flow. This could be detected by an upward inflection of the temperature versus time curve. Flow may be monitored for an increase in temperature, particularly above a predetermined threshold.

[0026] It is preferred that the metallic section 28 be located in close proximity to the cannula 14 (and, thereby, in close proximity to the hub 22). This allows for monitoring of fluid flow close to the cannula 14, providing a better indication of proper working. Obstructions or kinks in the conduit 16 may be not recognized with the metallic section 28 being located further upstream along the conduit 16 away from the cannula 14.

[0027] With the medical injector 10, including the conduit 16 being at room temperature, changes in temperature may be difficult to determine unless high-end temperature sensors are utilized, having high-level sensitivity. It is preferred that the conduit 16 be at a temperature higher than standard room temperature to better allow for detecting changes in temperature in monitoring flow. Body heat from the user may provide an elevated temperature. Advantageously, heat may be applied as a result of the medical injector 10 being mounted on the skin of the user. Alternatively, or in addition, with reference to Figure 3, an electric heatingelement 36, e.g., a resistor, may be utilized to generate and apply heat to the metallic section 28. Preferably, the electric heating element 36 applies heat prior to actuation of flow of the liquid drug 20, with temperature measurements being made by the temperature sensor 32. This allows for the baseline reading to be taken prior to flow of the liquid drug 20.

[0028] The temperature sensor 32 and the electric heating element 36 may be mounted to a common substrate 38, which may be a printed circuit board or the like. To avoid misreadings, it is preferred that the temperature sensor 32 be insulated (e.g., thermally insulated) from the electric heating element 36. This avoids thermal energy from the electric heating element 26 directly, and detrimentally, affecting the temperature sensor 32. The substrate 38 may be affixed to the body 12 or the hub 22.

[0029] Power for the temperature sensor 32 and the electric heating element 36 may be supplied from a power unit associated with the body 12 and / or a power supply locally provided, e.g., on the hub 22 (including on the substrate 38).

[0030] The CPU 34 may be provided with a memory for storing the temperature readings. In addition, a transmitter, e.g., a wireless transmitter, may be provided for transmitting the collected data to a remote location, e.g., for verification of proper dose administration. The transmitter may be mounted to the body 12 or the hub 22. The CPU 34 may be located on the body 12 or the hub 22.

[0031] A second temperature sensor 40 may be provided located for direct contact with the skin of the user to measure the skin of the user with the medical injector 10 being mounted to the skin of the user. Periodic temperature monitoring by the second temperature sensor 40 may provide an indication of how well secured the medical injector 10, or a portion thereof, is to the skin of the user. This is advantageous as flow of drug product can be stopped mid-injection in the event it is sensed that the medical injector 10 is no longer in suitable contact with the patient’s skin during injection. The CPU 34 may be electrically coupled with the second temperature sensor 40 to collect temperature readings of the second temperature sensor 40 for evaluation. With the temperature sensor 40 taking periodic readings over time, a temperature versus time relationship may be evaluated, as shown in Figure 6. As shown between T = 60 and T = 180 in Figure 6, there is a steady increase in temperature. If temperature readings show a drop in temperature, this may indicate a partial or full separation from the skin of the user. It is possible for the temperature to plateau representing a temperature of the skin. In addition, some variance in temperature is to be expected due to integrity of skin contact and inherent changes to skin temperature. As shown in Figure 6, a band of temperatures may be monitored over time defined by a curve (Top T) representing high end temperatures and the second curve representing low end temperatures (Bottom T). Notably, both curves have similar shapes. The curves can be monitored for a similar inflection in both curves.

[0032] As shown in Figure 5, the second temperature sensor 40 may be provided on the substrate 38, but on an opposite face from the temperature sensor 32 and the electric heating element 36. This arrangement allows for the second temperature sensor 40 to monitor the adherence of the hub 22, where provided separately from the body 12. This provides a specificindication of the adherence of the hub 22, and, thus, proper insertion of the cannula 14 into the skin of the user.

[0033] Optionally, a further temperature sensor may be provided for the body 12, which may be separately monitored in similar fashion to the second temperature sensor 40. This allows for monitoring of adhesion of the body 12, particularly where separately mounted from the hub 22. The CPU 34 may be electrically coupled to any further temperature sensors in similar fashion.

[0034] Same as the temperature sensor 32, the second temperature sensor 40, and any additional temperature sensors, may be one or more of: thermistor; thermocouple; semiconductor-based temperature sensor; and, resistance temperature detector (RTD). Data collected from these temperature sensors may be stored and transmitted in similar manner as discussed above. Power may be also provided in similar manner.

Claims

AMENDED CLAIMS received by the International Bureau on 06 March 2025 (06.03.2025)WHAT IS CLAIMED IS:

1. A medical injector for mounting onto the skin of a user for administering a dose of liquid drug to the user, the medical injector comprising: a body containing a reservoir of the liquid drug; a cannula for insertion into the skin of the user; a conduit for fluidically connecting the body and the cannula to allow the liquid drug to be conveyed to the cannula, wherein the conduit includes a tubular metallic section; a temperature sensor for measuring the temperature of the metallic section; and, a CPU for collecting periodic temperature measurements from the temperature sensor to determine change in temperature between sequential periodic temperature measurements from the temperature sensor of the metallic section in evaluating flow of the liquid drug through the conduit.

2. The medical injector of claim 1, wherein the temperature sensor is one or more of: thermistor; thermocouple; semiconductor-based temperature sensor; resistance temperature detector (RTD); and, infrared (IR) temperature sensor.

3. The medical injector of claim 1, wherein the metallic section is located in close proximity to the cannula.

4. The medical injector of claim 1, further comprising an actuator to initiate delivery of the liquid drug from the reservoir and into the conduit for conveyance to the cannula.

5. The medical injector of claim 4, wherein the temperature sensor measures the temperature of the metallic section prior to initiation of delivery of the liquid drug.

6. The medical injector of claim 1, further comprising a second temperature sensor for direct contact with the skin of the user to measure the temperature of the skin of the user with the medical injector mounted onto the skin of the user.

7. The medical injector of claim 6, wherein the CPU collects periodic temperature measurements from the second temperature sensor.

8. The medical injector of claim 6, wherein the cannula is mounted to a hub separate, and spaced from, the body, and, wherein, the second temperature sensor is associated with the hub.

9. The medical injector of claim 1, wherein the metallic section has a generally constant internal cross-section.

10. The medical injector of claim 1, wherein the cannula is mounted to a hub separate, and spaced from, the body.

11. The medical injector of claim 10, wherein the metallic section is located along the conduit between the body and the hub.

12. The medical injector of claim 11, wherein the metallic section is located in close proximity to the hub.

13. The medical injector of claim 1, wherein portions of the conduit adjacent to the metallic section are non-metallic.

14. A medical injector for mounting onto the skin of a user for administering a dose of liquid drug to the user, the medical injector comprising: a body containing a reservoir of the liquid drug; a cannula for insertion into the skin of the user; a conduit for fluidically connecting the body and the cannula to allow the liquid drug to be conveyed to the cannula, wherein the conduit includes a tubular metallic section; an electric heating element configured to generate and apply heat to the metallic section; a temperature sensor, insulated from the heating element, for measuring the temperature of the metallic section; and, a CPU for collecting periodic temperature measurements from the temperature sensor to determine change in temperature between sequential periodic temperature measurements from the temperature sensor of the metallic section in evaluating flow of the liquid drug through the conduit.

15. The medical injector of claim 14, wherein the temperature sensor is one or more of: thermistor; thermocouple; semiconductor-based temperature sensor; resistance temperature detector (RTD); and, infrared (IR) temperature sensor.

16. The medical injector of claim 14, wherein the heating element and the temperature sensor are mounted to a common substrate.

17. The medical injector of claim 14, wherein the metallic section is located in close proximity to the cannula.

18. The medical injector of claim 14, wherein the heating element is a resistor.

19. The medical injector of claim 14, further comprising an actuator to initiate delivery of the liquid drug from the reservoir and into the conduit for conveyance to the cannula.

20. The medical injector of claim 19, wherein the heating element applies heat to the metallic section prior to initiation of delivery of the liquid drug.

21. The medical injector of claim 20, wherein the temperature sensor measures the temperature of the metallic section prior to initiation of delivery of the liquid drug.

22. The medical injector of claim 14, further comprising a second temperature sensor for direct contact with the skin of the user to measure the temperature of the skin of the user with the medical injector mounted onto the skin of the user.

23. The medical injector of claim 22, wherein the CPU collects periodic temperature measurements from the second temperature sensor.

24. The medical injector of claim 22, wherein the cannula is mounted to a hub separate, and spaced from, the body, and, wherein, the second temperature sensor is associated with the hub.

25. The medical injector of claim 14, wherein the metallic section has a generally constant internal cross-section.

26. The medical injector of claim 14, wherein the cannula is mounted to a hub separate, and spaced from, the body.

27. The medical injector of claim 26, wherein the metallic section is located along the conduit between the body and the hub.

28. The medical injector of claim 27, wherein the metallic section is located in close proximity to the hub.

29. The medical injector of claim 14, wherein portions of the conduit adjacent to the metallic section are non-metallic.

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