EP4719204A1

EP4719204A1 - Medication delivery systems and methods including injection site determination and tracking

Info

Publication number: EP4719204A1
Application number: EP24737203.0A
Authority: EP
Inventors: Kelsey Christine BAYER; Brandon James DAVIS; Kevin Harrison Duffy; Kaitlyn Mary EDDY; Julia Kay SCHNELKER; Joseph Edward KATUIN; Ariel Marie Roberts
Original assignee: Eli Lilly and Co
Current assignee: Eli Lilly and Co
Priority date: 2023-05-31
Filing date: 2024-05-31
Publication date: 2026-04-08
Also published as: CN121218930A; WO2024249788A1; AU2024282061A1

Abstract

A medication delivery system includes a housing and a medication delivery assembly carried by the housing. The medication delivery assembly delivers a medication to an injection site of a subject via an injection aperture. An ultrasound transducer is carried by the housing proximate to the injection aperture. The ultrasound transducer emits ultrasound waves into tissue of the subject at the injection site and receives reflected ultrasound waves from the tissue of the subject. A processor determines whether the reflected ultrasound waves indicate the presence of bone in the tissue of the subject. (1) When bone is present in the tissue, the processor determines that the injection site is located at an appendage of the subject; and (2) the processor otherwise determines that the injection site is located at an abdomen of the subject.

Description

MEDICATION DELIVERY SYSTEMS AND METHODS

INCLUDING INJECTION SITE DETERMINATION AND TRACKING

FIELD OF THE DISCLOSURE

[0001] The present disclosure relates to medication delivery systems, and, in particular, to medication delivery systems including ultrasound transducers that facilitate determining injection sites on bodies of patients.

BACKGROUND

[0002] Patients suffering from various diseases frequently must inject themselves with medication. To permit patients to conveniently and accurately self-administer medication, a variety of medication delivery systems, including injector pens, have been developed. Use of such systems at repeated injection sites on the body (for example, the arms, the thighs, and the abdomen) can cause lipohypertrophy and inhibit proper absorption of medication into the subcutaneous tissue. As such, patients typically avoid consecutive use of an injection site and instead alternate between various injection sites. However, recalling or tracking injection site use can be burdensome for patients. Accordingly, it would be desirable to provide medication delivery systems that facilitate tracking injection site use and alternating between different injection sites.

SUMMARY

[0003] According to an embodiment of the present disclosure, a medication delivery system is provided. The system includes a housing and a medication delivery assembly carried by the housing. The medication delivery assembly is configured to deliver a medication to an injection site of a subject via an injection aperture. An ultrasound transducer is carried by the housing proximate to the injection aperture. The ultrasound transducer is configured to emit ultrasound waves into tissue of the subject at the injection site and receive reflected ultrasound waves from the tissue of the subject. A processor is operably coupled to the ultrasound transducer. The processor is configured to determine whether the reflected ultrasound waves indicate the presence of bone in the tissue of the subject. (1) When bone is present in the tissue, the processor determines that the injection site is located at an appendage of the subject; and (2) the processor otherwise determines that the injection site is located at an abdomen of the subject.

[0004] According to another embodiment of the present disclosure, a medication delivery system is provided. The medication delivery system includes a housing including an injection aperture and a medication delivery assembly carried by the housing. The medication delivery assembly is configured to extend through the injection aperture and deliver a medication to an injection site of a subject. A plurality of ultrasound transducers are carried by the housing and disposed around the injection aperture. The plurality of ultrasound transducers are configured to emit ultrasound waves into tissue of the subject at the injection site and receive reflected ultrasound waves from the tissue of the subject. A processor is operably coupled to the plurality of ultrasound transducers, and the processor is configured to determine a body location of the injection site of the subject based on the reflected ultrasound waves.

[0005] According to yet another embodiment of the present disclosure, a method for delivering a medication to a subject is provided. The method includes emitting, via an ultrasound transducer carried by a medication delivery device, ultrasound waves into tissue of the subject at an injection site; receiving, via the ultrasound transducer, reflected ultrasound waves from the tissue of the subject; determining, via a processor operably coupled to the ultrasound transducer, whether the reflected ultrasound waves indicate the presence of bone in the tissue of the subject, and (1) upon determining the presence of bone in the tissue, determining that the injection site is located at an appendage of the subject; and (2) otherwise determining that the injection site is located at an abdomen of the subject; and injecting, via the medication delivery device, the medication into the tissue of the subject at the injection site.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: [0007] FIG. 1 is a side view of a medication delivery system according to an embodiment of the present disclosure.

[0008] FIG. 2 is a schematic view of the drug delivery system of FIG °1.

[0009] FIG. 3 is a detail perspective view of a distal end of a medication delivery device of the system of FIG. 1.

[0010] FIG. 4 is an exemplary illustration of ultrasound waves emitted by a medication delivery device including six ultrasound transducers, according to an embodiment of the present disclosure.

[0011] FIG. 5 is an exemplary plot of pixel intensity, corresponding to the magnitude of reflected ultrasound waves received by the medication delivery system of FIG. 1, versus tissue depth.

[0012] FIG. 6 is an exemplary electrocardiogram (ECG) signal determined by the medication delivery system of FIG. 1.

[0013] FIG. 7 is an exemplary plot of cardiac cycle pattern voltages, specifically differences between maximum R wave and minimum Q wave voltages, experimentally sensed by the medication delivery system of FIG. 1 in a laboratory environment.

[0014] FIG. 8 is an exemplary plot of cardiac cycle pattern voltages, specifically minimum Q wave voltages, experimentally sensed by the medication delivery system of FIG.

1 in a laboratory environment.

[0015] FIG. 9 is a flow diagram of a method for delivering a medication to a subject using the medication delivery system of FIG. 1.

[0016] FIG. 10 is another portion of the flow diagram of the method for delivering the medication to the subject of FIG. 9.

[0017] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. DETAILED DESCRIPTION

[0018] Medication delivery systems according to the present disclosure carry and delivery one or more medications, which may also be referred to as therapeutic agents or drugs. Such medications may include, for example, epinephrine, anesthetics, analgesics, steroids, insulins, insulin analogs, insulin derivatives, GLP-1 receptor agonists, therapeutic antibodies, or any other medication that is capable of delivery by systems according to the present disclosure. Medication delivery systems according to the present disclosure are operated in a manner generally as described herein by a user (for example, a healthcare professional, a caregiver, or another person) to deliver one or more medications to a subject (for example, another person or the user).

[0019] FIG. 1 illustrates a medication delivery system 10 according to an exemplary embodiment of the present disclosure. The medication delivery system 10 includes a medication delivery device 12. The medication delivery device 12 illustratively has an injector pen-like shape, although other shapes may alternatively be used. The medication delivery device 12 includes a housing 14 having a proximal end 16 and an opposite distal end 18. During use of the medication delivery device 12, the proximal end 16 is farther from the subject and configured to be actuated by the user, and the distal end 18 is closer to the subject and configured to deliver the medication (shown elsewhere) to the subject. The medication delivery device 12 also includes a longitudinal axis A extending between the proximal end 16 and the distal end 18.

[0020] With continued reference to FIG. 1, the housing 14 internally carries a medication delivery assembly 20. Generally, the medication delivery assembly 20 includes a reservoir 22 that carries medication and a needle 24 in fluid communication with the reservoir 22. The needle 24 is selectively movable from a stowed configuration (as illustrated) to a deployed configuration (not illustrated) in which the needle 24 extends through an injection aperture 26 disposed at the distal end 18 of the housing 14. The needle 24 is configured to pierce the skin of a subject in the deployed configuration and thereby deliver the medication from the reservoir 22 to the subject. The medication delivery assembly 20 may take various forms. For example, the medication delivery assembly 20 may include mechanical, hydraulic, pneumatic, or electric drive mechanisms for moving the needle 24, or the needle 24 and the reservoir 22, from the stowed configuration to the deployed configuration and vice versa. The medication delivery assembly 20 may additionally or alternatively include mechanical, hydraulic, pneumatic, or electric drive mechanisms for delivering the medication from the reservoir 22 to the needle 24 and the subject. As a specific example, the reservoir 22 may be a syringe that receives a piston, and the piston is driven in the syringe to deliver the medication from the reservoir 22 to the needle 24 and the subject. As another specific example, the reservoir 22 may be a compressible bladder that is hydraulically or pneumatically compressed to deliver the medication from the reservoir 22 to the needle 24 and the subject. The medication delivery assembly 20 may be configured as a wearable infusion device that delivers medication over a prolonged period of time (e.g., minutes or hours), or it may be configured to deliver medication over a relatively short time (e g., seconds). In some embodiments, the medication delivery assembly 20 may initiate a chemical reaction to drive an injection, e.g., by using gases produced by a chemical reaction to move pistons, levers, or compressible bladders to deliver the medication.

[0021] In some embodiments, the device 12 is a reusable device. More specifically, the medication delivery assembly 20, or one or more components thereof, are replaceable after the medication is depleted from the reservoir 22, and the device 12 may again be used to deliver medication to a subject. In other embodiments, the device 12 is a single use device. More specifically, the device 12 is discarded after the medication is depleted from the reservoir 22.

[0022] With continued reference to FIG. 1 and additional reference to FIG. 2, the system 100 also includes various other components that facilitate delivering the drug to a subject. For example, the device 12 includes a processor 28 that operably couples to various components and thereby facilitates delivery of the medication to the subject. The processor 28 may be or include, for example, one or more Field Programmable Gate Arrays (FPGAs), one or more Programmable Logic Devices (PLDs), one or more Complex PLDs (CPLDs), one or more custom Application Specific Integrated Circuits (ASICs), one or more dedicated processors (e.g., microprocessors), or the like. The processor 28 may operably couple to the medication delivery assembly 20 and a user input 30, and the user input 30 is operable to actuate the medication delivery assembly 20. In other embodiments, the processor 28 does not operably couple to one or more of the medication delivery assembly 20 and the user input 30. The processor 28 also operably couples to a power source 32 (not shown - such as one or more batteries), a memory 34, and a transmitter 36 for operably coupling the device 12 to one or more remote devices 38, such as smartphones. In addition, the processor 28 operably couples to one or more ultrasound transducers 40 (for example, capacitive micromachined ultrasound transducers (CMUTs)), a first electrode 42, and a second electrode 44. As described in further detail below, the ultrasound transducers 40 and the electrodes 42, 44 facilitate determining and tracking injection sites used by the subject.

[0023] FIG. 3 illustrates an exemplary embodiment of the distal end 18 of the medication delivery device 12, although some portions of the housing 14 are hidden so that other features of the device 12 are visible. In some embodiments and as illustrated, the distal end 18 of the device 12 carries a plurality of ultrasound transducers 40 (illustratively, three ultrasound transducers 40) that are disposed around the injection aperture 26. Alternatively, medication delivery devices according to embodiments of the present disclosure may have different numbers of ultrasound transducers (for example, one, two, four, five, six, or more ultrasound transducers). The ultrasound transducers 40 may be disposed apart by substantially equal angles a around the injection aperture 26 (that is, equal ± 5 degrees). Said ultrasound transducers may be coupled to a pulsing component or circuit (not shown) which generates a high frequency, high voltage electrical pulse to the transducer to cause the transducer to emit ultrasound. Furthermore, said ultrasound transducers may include a sensor for detecting reflected or returning ultrasound signals, as well as an amplifier to boost the return signal for a processor to process.

[0024] One or more of the ultrasound transducers 40 may be positioned to emit ultrasound waves at acute angles 0 away from the longitudinal axis A of the housing 14. As shown in FIG. 4, which illustrates ultrasound waves 41A, 41B, 41C, 41D, 41E, and 41F emitted by an exemplary medication delivery device including six ultrasound transducers, the acute angles provide the ultrasound transducers with a relatively high likelihood of collectively emitting ultrasound waves toward bone B within the subject S. In some embodiments, the acute angles 0 are substantially 10 degrees (that is, 10 degrees ± 2.5 degrees). Alternatively, medication delivery devices according to embodiments of the present disclosure may have different arrangements of ultrasound transducers (for example, one, two, four, five, six, or more ultrasound transducers).

[0025] With general reference again to FIGS. 1 and 2, the ultrasound transducer(s) 40 is (are) configured to emit ultrasound waves into tissue of the subject at an injection site and receive reflected ultrasound waves from the tissue of the subject. Based on the reflected ultrasound waves received by the ultrasound transducer(s) 40, the processor 28 determines the location of the injection site. More specifically, the processor 28 determines whether the reflected ultrasound waves indicate the presence of bone in the tissue of the subject. With additional reference to FIG. 5, the presence of bone is indicated by receiving a high magnitude of reflected ultrasound waves from certain tissue depths (illustratively, at about 16mm) and a low magnitude of reflected ultrasound waves from deeper tissue (illustratively, between about 17mm and 30mm). When the processor 28 (1) determines that bone is present in the tissue, the processor 28 determines that the injection site is located at an appendage of the subject; and (2) the processor 28 otherwise determines that the injection site is located at the abdomen of the subject (because the ultrasound waves are unlikely to be reflected by the spine of the subject). In the former situation, the processor 28 may determine that the injection site is located at an appendage by determining whether the appendage is an arm or a thigh of the subject. More specifically, the processor 28 may determine whether the appendage is an arm or a thigh of the subject by determining the bone depth of the tissue, and (1A) when the bone depth is greater than a threshold (for example, 15mm), the processor 28 determines that the appendage is a thigh of the subject; and (IB) when the bone depth is less than the threshold, the processor 28 determines that the appendage is an arm of the subject.

[0026] For devices 10 that include a plurality of ultrasound transducers 40, the processor 28 may analyze the reflected ultrasound waves received by each transducer 40 in various manners. For example, the processor 28 may analyze the average magnitude of the reflected ultrasound waves received by all of the transducers 40. As another example and with further reference to FIG. 4, the processor 28 may analyze the reflected ultrasound waves received by the transducers 40 that indicate the presence of bone near an injection site (for example, the transducers that emitted the ultrasound waves 41C, 4 ID, and 4 IE) and ignore any transducers that do not indicate the presence of bone near the injection site (for example, the transducers that emitted the ultrasound waves 41A, 41B, and 41F).

[0027] With general reference again to FIGS. 1 and 2, the processor 28 determines whether the injection site of the subject is on the right side or the left side of the subject based on electrical signals received via the electrodes 42, 44. In some embodiments, electrodes 42, 44 may be tied to a differential amplifier (not shown) before being routed to processor 28. More specifically, the first electrode 42 contacts a first skin surface of the subject (for example, skin at the injection site), and the second electrode 44 contacts a second skin surface of the subject (for example, skin on the hand of the subject), and the processor 28 thereby receives electrical signals corresponding to the cardiac cycle pattern of subject. With additional reference to FIG. 6, the processor 28 thereby determines an electrocardiogram (ECG) signal. The processor 28 may determine all portions of the ECG signal for one or more cardiac cycles, such as the P wave, the Q wave, the R wave, the S wave, and the T wave, or the processor 28 may only determine relevant portions of the ECG signal, specifically portions including the Q wave and the R wave as described in further detail below, for one or more cardiac cycles.

[0028] With continued reference to FIG. 6 and additional reference to FIGS. 7 and 8, the processor 28 may analyze one or more portions of the ECG signal to determine whether the injection site of the subject is on the right side or the left side of the subject. FIGS. 7 and 8 illustrate values of the ECG signal experimentally observed by the device 12 in a laboratory environment setting. As illustrated, the values can be differentiated into different levels, or relative to various thresholds, (1) based on whether the injection site is on the right side or the left side of the subject, and (2) whether the right hand or the left hand of the subject held the device against the injection site. More specifically, the processor 28 determines a maximum amplitude of the R wave and a minimum amplitude of the Q wave. Such amplitudes may be for a single cardiac cycle, averaged or smoothed values over multiple cardiac cycles, or the like. As shown in FIG. 7 by the voltage values within a first box 110, if the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is greater than a first threshold (for example, 2m V) and less than a second threshold (for example, 3mV), then the subject is likely holding the device 12 against the right side of his body using his right hand. As shown in FIG. 7 by the voltage values within a second box 112, if the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is greater than the second threshold, then the subject is likely holding the device 12 against the left side of his body using his right hand. As shown in FIG. 7 by the voltage values within a third box 114, if the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is less than the first threshold, then the subject is likely holding the device 12 against either the left or the right side of his body using his left hand. If the subject is holding the device 12 using his left hand, determining whether the subject is pressing the device 12 against the left or the right side of his body may be determined by calculating the minimum amplitude of the Q wave. For example, if the subject is holding the device 12 using his left hand, and if, as shown in FIG. 8 by the voltage values within a fourth box 116, the minimum amplitude of the Q wave is greater than a third threshold (for example, -0.5mV), then the subject is likely holding the device 12 against the left side of his body using his left hand. And if, as shown in FIG. 8 by the voltage values within a fifth box 118 or a sixth box 120, the minimum amplitude of the Q wave is less than the third threshold, then the subject is likely holding the device 12 against the right side of his body using his left hand.

[0029] In summary therefore, by considering signals received from the ultrasound transducer(s) 40, the processor 28 is capable of determining which body part an injection site is at (e.g., an arm, a leg, or an abdomen). By considering signals from the electrodes 42, 44, the processor 28 is capable of determining which side of the body the injection site is at (e.g., left or right side of the body). By considering both signals received from the ultrasound transducer(s) 40 and the electrodes 42, 44, the processor 28 is capable of distinguishing six specific injection sites on the body of subject, specifically the right thigh, the left thigh, the right arm, the left arm, the right side of the abdomen, and the left side of the abdomen. The processor 28 provides injection site data, via the transmitter 36, to the remote device 12, which may incorporate the data into an injection site tracking application. Alternatively, the device 12 may present injection site data via a display.

[0030] FIGS. 9 and 10 illustrates a flow diagram of a method for delivering a medication to a subject using the medication delivery system 10. As shown in FIG. 9, at block 210, the processor 28 determines that the device 12 is in contact with the skin of the subject. Such contact may be determined via the electrodes 42, 44, more specifically by detecting the presence of closed circuit defined together by the device 12 and the subject. At block 212, the processor 28 determines, via the electrodes 42, 44, the side of the subject’s body in contact with the device 12. More specifically, the processor 28 analyzes one or more portions of an ECG signal to determine the side of the subject’s body in contact with the device 12. Even more specifically and referring to FIG. 10, at sub-block 310 the processor 28 determines a maximum amplitude of an R wave of the EGC signal, a minimum amplitude of a Q wave of the ECG signal, and a difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave. At sub-block 312, the processor 28 compares the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave to a first threshold and a second threshold. If the difference is greater than the first threshold and less than the second threshold (e.g., similar to the injection voltage values depicted in box 110 of FIG. 7), at sub-block 314 the processor 28 determines that the injection site is on the right side of the subject. Otherwise, the method proceeds to sub-block 316. At sub-block 316, the processor 28 compares the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave to the second threshold If the difference is greater than the second threshold (e.g., similar to the injection voltage values depicted in box 112 of FIG. 7), at sub-block 318 the processor 28 determines that the injection site is on the left side of the subject. Otherwise, the method proceeds to sub-block 320. At sub-block 320, the processor 28 compares the minimum amplitude of the Q wave to a third threshold. If the minimum amplitude of the Q wave is greater than the third threshold (e g., similar to the injection voltage values depicted in box 116), at sub-block 322 the processor 28 determines that the injection site is on the left side of the subject. Otherwise, more specifically if the minimum amplitude of the Q wave is less than the third threshold, at sub-block 324 the processor 28 determines that the injection site is on the right side of the subject. With reference again to FIG. 9, at block 214 the processor 28 determines, via the ultrasound transducer(s) 40, the body location in contact with the device 12. More specifically, the processor 28 determines whether or not bone is present in tissue near the injection site, and the depth of any such bone, as described in connection with FIG. 5. In this way, the processor 28 can determine whether the injection site is at an arm, a thigh, or an abdomen of the subject. The device 12 then transmits injection site data to the remote device 12 and, at block 216, the device 12 delivers the medication to the subject via the medication delivery assembly 20.

[0031] Systems and methods according to embodiments of the present disclosure may be modified in various manners. For example, the device 12 could transmit signals from the ultrasound transducer(s) 40 and/or the electrodes 42, 44 to the remote device 12, and a processor of the remote device 12 could then determine the location of an injection site using any of the methods contemplated herein. Furthermore, the blocks of FIG. 9 may be rearranged in any logical order. For instance, block 216 (delivery of medication) may occur concurrently with, or before, block 212 and 214. Block 214 may occur concurrently with or before block 212.

[0032] While this invention has been shown and described as having preferred designs, the present invention may be modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.

Claims

WHAT IS CLAIMED IS:

1. A medication delivery system, comprising: a housing; a medication delivery assembly carried by the housing and configured to deliver a medication to an injection site of a subject via an injection aperture; an ultrasound transducer carried by the housing proximate to the injection aperture and configured to emit ultrasound waves into tissue of the subject at the injection site and receive reflected ultrasound waves from the tissue of the subject; and a processor operably coupled to the ultrasound transducer, the processor configured to determine whether the reflected ultrasound waves indicate bone is present in the tissue of the subject, and (1) when bone is present in the tissue, determine that the injection site is located at an appendage of the subject; and (2) otherwise determine that the injection site is located at an abdomen of the subject.

2. The medication delivery system of claim 1, wherein, when bone is present in the tissue, the processor is configured to determine whether the appendage is an arm or a thigh of the subject.

3. The medication delivery system of claim 2, wherein the processor is configured to determine whether the appendage is an arm or a thigh of the subject by determining bone depth of the tissue, and (1 A) when the bone depth is greater than a threshold, determining that the appendage is a thigh of the subject; and (IB) when the bone depth is less than the threshold, determining that the appendage is an arm of the subject.

4. The medication delivery system of any of claims 1-3, further comprising: a first electrode carried by the housing and operably coupled to the processor, the first electrode configured to contact skin of the subject; and a second electrode carried by the housing and operably coupled to the processor, the second electrode configured to contact the skin of the subject; wherein the processor is configured to determine an electrocardiogram (ECG) signal via the first electrode and the second electrode, and determine whether the injection site of the subject is on the right side or the left side of the subject based on the ECG signal.

5. The medication delivery system of claim 4, wherein the processor is further configured to determine a maximum amplitude of an R wave of the EGC signal and a minimum amplitude of a Q wave of the ECG signal, and:

(1) when the processor determines that a difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is greater than a first threshold and less than a second threshold, the processor is configured to determine that the tissue is on the right side of the subject;

(2) when the processor determines that the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is greater than the second threshold, the processor is configured to determine that the tissue is on the left side of the subject;

(3) when the processor determines that the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is less than the first threshold and the minimum amplitude of the Q wave is greater than a third threshold, the processor is configured to determine that the tissue is on the left side of the subject; and

(4) when the processor determines that the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is less than the first threshold and the minimum amplitude of the Q wave is less than the third threshold, the processor is configured to determine that the tissue is on the right side of the subject.

6. The medication delivery system of any of claims 1-5, wherein the processor is carried by the housing.

7. A medication delivery system, comprising: a housing comprising an injection aperture; a medication delivery assembly carried by the housing and configured to extend through the injection aperture and deliver a medication to an injection site of a subject; a plurality of ultrasound transducers carried by the housing and disposed around the injection aperture, the plurality of ultrasound transducers configured to emit ultrasound waves into tissue of the subject at the injection site and receive reflected ultrasound waves from the tissue of the subject; and a processor operably coupled to the plurality of ultrasound transducers, the processor configured to determine a body location of the injection site of the subject based on the reflected ultrasound waves.

8. The medication delivery system of claim 7, wherein the processor is configured to determine the body location of the injection site by determining whether the reflected ultrasound waves received by at least one of the plurality of ultrasound transducers indicates bone is present in the tissue, and (1) upon determining bone is present in the tissue, determining that the body location is an appendage; and (2) otherwise determining that the tissue is abdominal tissue.

9. The medication delivery system of claim 8, wherein the processor is configured to determine that the body location is an appendage by determining whether the appendage is an arm or a thigh of the subject.

10. The medication delivery system of claim 8, wherein the processor is configured to determine that the body location is an appendage by determining bone depth of the tissue, and (1A) when the bone depth is greater than a threshold, determining that the appendage is a thigh of the subject; and (IB) when the bone depth is less than the threshold, determining that the appendage is an arm of the subject.

11. The medication delivery system of any of claims 7-10, wherein the housing comprises a longitudinal axis, and the ultrasound transducers are positioned to emit ultrasound waves at an acute angle away from the longitudinal axis.

12. The medication delivery system of claim 11, wherein the acute angle is substantially 10 degrees.

13. The medication delivery system of any of claims 7-12, wherein the plurality of ultrasound transducers are spaced apart by substantially equal angles around the injection aperture.

14. The medication delivery system of any of claims 7-12, further comprising: a first electrode carried by the housing and operably coupled to the processor, the first electrode configured to contact skin of the subject; and a second electrode carried by the housing and operably coupled to the processor, the second electrode configured to contact the skin of the subject; wherein the processor is configured to determine an electrocardiogram (ECG) signal via the first electrode and the second electrode, and determine whether the injection site of the subject is on the right side or the left side of the subject based on the ECG signal.

15. The medication delivery system of claim 12, wherein the processor is further configured to determine a maximum amplitude of an R wave of the EGC signal, a minimum amplitude of a Q wave of the ECG signal, and:

16. A method for delivering a medication to a subject, the method comprising: emitting, via an ultrasound transducer carried by a medication delivery device, ultrasound waves into tissue of the subject at an injection site; receiving, via the ultrasound transducer, reflected ultrasound waves from the tissue of the subject; determining, via a processor operably coupled to the ultrasound transducer, whether the reflected ultrasound waves indicate bone is present in the tissue of the subject, and (1) upon determining bone is present in the tissue, determining that the injection site is located at an appendage of the subject; and (2) otherwise determining that the injection site is located at an abdomen of the subject; and injecting, via the medication delivery device, the medication into the tissue of the subject at the injection site.

17. The method of claim 16, wherein determining that the injection site is located at an appendage of the subject comprises determining whether the appendage is an arm or a thigh of the subj ect

18. The method of claim 16, wherein determining that the injection site is located at an appendage of the subject comprises determining bone depth of the tissue, and (1A) when the bone depth is greater than a threshold, determining that the appendage is a thigh of the subject; and (IB) when the bone depth is less than the threshold, determining that the appendage is an arm of the subject.

19. The method of any of claims 16-18, further comprising: determining, via the processor, a first electrode carried by the medication delivery device, and a second electrode carried by the medication delivery device, an electrocardiogram (ECG) signal; and determining, via the processor, whether the injection site is on the right side or the left side of the subject based on the ECG signal.

20. The method of claim 19, wherein determining, via the processor, whether the injection site is on the right side or the left side of the subject based on the ECG signal comprises determining a maximum amplitude of an R wave of the EGC signal and a minimum amplitude of a Q wave of the ECG signal, and:

(1) when a difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is greater than a first threshold and less than a second threshold, determining that the tissue is on the right side of the subject;

(2) when the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is greater than the second threshold, determining that the tissue is on the left side of the subject;

(3) when the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is less than the first threshold, and the minimum amplitude of the Q wave is greater than a third threshold, determining that the tissue is on the left side of the subject; and (4) when the difference between the maximum amplitude of the R wave and the minimum amplitude of the Q wave is less than the first threshold, and the minimum amplitude of the Q wave is less than the third threshold, determining that the tissue is on the right side of the subject.