Medical module for drug delivery pen

Various embodiments of a medical module are provided which includes a primary module housing, a secondary module housing, a dosage sensor, a power source, and a microcontroller. The module is configured to be attached to a disposable drug delivery pen or a reusable drug delivery pen so that the module may: determine dosage selected, injection of selected dosage, duration of injection, time of injection, whether the pen has been primed or shaken to thoroughly mix up insulin mixtures, transmit information relating to insulin dosage and injection to a data management unit, provide reminders, error warning or messages on improper usage or reusage of needles, track amount of drug remaining on board the pen or duration of usage of pen with respect to expiry of the drug on board, or provide an audible alarm for locating misplaced pen and module.

BACKGROUND

It is believed that five million people worldwide, or approximately 56% of all insulin users, use insulin pens to inject their insulin. Insulin pens are convenient, easy to use, and discrete compared to syringes and vials, resulting in improved adherence and better outcomes. In addition, insulin pens reduce the time required for health care practitioners to initiate insulin therapy.

SUMMARY OF THE DISCLOSURE

Embodiments of the present invention address key issues, including: bringing together insulin therapy and blood glucose monitoring into more integrated therapeutic/monitoring systems; simplifying insulin initiation and intensification protocols; making blood glucose values central in the management of diabetes; and providing diabetes system solutions for improved outcomes and lower costs. The embodiments of the present invention help the patient and care provider stay on top of insulin therapy by automatically communicating delivered doses to a blood glucose meter, by recording the amount and time of insulin delivery, and by displaying a summary of a patient's blood glucose and insulin administration history. The embodiments of the present invention confirm whether the patient has already dosed, keeps track of the time and amount of insulin delivery, and eliminates the need to keep a manual logbook. Embodiments of the present invention help health care practitioners keep track of patient compliance.

Not only will embodiments of the invention facilitate management of diabetes, the invention and its embodiments will also be applicable in any field where drug delivery to a patient is utilized. For example, in the field of pain management or arthritis management, anxiety or epilepsy management (e.g., Diazepam) and the like.

In view of the foregoing and in accordance with one aspect of the present invention, there is provided a medical module that includes a primary module housing, a secondary module housing, a dosage sensor, a power source, and a microcontroller. The module housing extends along a first longitudinal axis from a first module housing end to a second module housing end. The secondary module housing is coupled to the casing module and extends along a second axis to define a hollow bore, which hollow bore is configured for attachment over an actuation unit of a drug delivery pen. The dosage sensor is coupled to the primary module housing, while the power source is coupled to the primary module housing and is spaced apart from the dosage sensor. The microcontroller is disposed in the primary module housing and is coupled to both the dosage sensor and the power source.

In yet a further aspect, the secondary module housing includes first and second extensions that partially circumscribe the second longitudinal axis generally parallel to the first longitudinal axis.

In yet a further aspect, each of the first and second extensions includes respective first and second locating tangs, which protrude beyond each extension.

In yet a further aspect, the first locating tang is located at a position along the second longitudinal axis offset longitudinally with respect to the second locating tang.

In yet a further aspect, each of the first and second extensions defines a generally circular cross-section of generally 30 degrees about the second longitudinal axis.

In yet a further aspect, a portion of the secondary module housing circumscribes the second longitudinal axis to define a generally circular cross-section of generally 140 degrees about the longitudinal axis.

In yet a further aspect, a portion of the secondary module housing is contiguous to both the first and second extensions, defining a continuous surface that circumscribes generally 250 degrees about the second axis.

In yet a further aspect, the dosage sensor includes a longitudinal member slidable along the longitudinal axis. The longitudinal member is connected to a follower portion that extends from the primary module housing proximate the second module housing end.

In yet a further aspect, the longitudinal member is configured for rotation about its axis.

In yet a further aspect, the secondary module housing includes a generally tubular extension circumscribing entirely the second longitudinal axis and defining a hollow bore that extends along a length of the module housing.

In yet a further aspect, the microcontroller includes: a memory; a microprocessor coupled to the memory; an analog-to-digital converter coupled to the dosage sensor and the microprocessor so as to provide data on displacement of the follower portion; and a transmitter to transmit data stored in the memory.

In yet a further aspect, the drug delivery pen includes a disposable insulin pen.

In yet a further aspect, the drug delivery pen includes a reusable insulin pen.

In yet a further aspect, the dosage sensor is selected from a group consisting of a rotary potentiometer, linear potentiometer, capacitive displacement sensor, optical displacement sensor, magnetic displacement sensor, encoder type displacement sensor, or combination thereof.

In yet a further aspect, an inertial sensor is disposed in the module housing to determine the orientation of the drug delivery pen.

In yet a further aspect, a micro switch is disposed in the module housing to allow determination of replacement of the drug delivery pen.

In another aspect of the present invention, there is provided a medical communication unit that includes a housing, dosage sensor, knob, and micro-controller. The housing extends along a longitudinal axis from a first housing end to a second housing end to define at least a portion of a hollow bore in which the hollow bore is configured to couple over an actuation unit of a drug delivery pen. The dosage sensor is coupled to the housing and offset to the longitudinal axis. The knob is mounted to the housing and coupled to the dosage sensor. The micro-controller is disposed proximate the housing and the dosage sensor.

In yet a further aspect, a medical communication unit is provided that includes a housing, means for measuring displacement of a drug delivery pen, and means for determining one of a dosage delivery or duration of the dosage delivery of a drug delivery pen. The housing extends along a longitudinal axis from a first housing end to a second housing end to define at least a portion of a hollow bore in which the hollow bore is configured to couple over an actuation unit of a drug delivery pen.

These and other embodiments, features and advantages will become apparent when taken with reference to the following more detailed description of the embodiments of the invention in conjunction with the accompanying drawings that are first briefly described.

DETAILED DESCRIPTION OF THE FIGURES

Insulin pens are commonly used as a simple, convenient, and effective technique for delivering insulin. Unlike syringes, which must be filled from a vial and require the user to estimate the dose volume based on the position of a meniscus against a fine graduated scale, insulin pens are accurate and relatively easy to use. Insulin pens come in two basic types: (1) disposable pens that come pre-loaded with the insulin cartridge and are thrown away after the cartridge is empty, and (2) re-usable pens that require the user to load the insulin cartridges. Most insulin pens are purely mechanical, but there are versions on the market that have digital displays and record the most recent dosing history in memory (see, for example, the Humapen Memoir). To use a pen, the user attaches a needle, primes the device, dials in the desired dose, inserts the needle subcutaneously, and then presses a button to inject.

Despite the simplicity and ease of use of insulin pens relative to syringes, applicants have recognized that there are aspects that may be improved. For example, applicants note that the typical disposable pens do not record insulin delivery events. This makes it difficult for the patient and their doctor to retrospectively analyze insulin delivery patterns and the relationship with blood glucose data. This is necessary to help the user and their doctor understand the relationship between blood glucose levels and insulin delivery in order to optimize insulin dosing. In addition, patients who have forgotten whether or not they have taken their insulin have no way to verify a delivery event. A missed injection may result in hyperglycemia (two missed bolus shots per week is known to raise HbA1C levels), and taking too much insulin could result in a life-threatening hypoglycemic event. While models such as the Humapen Memoir record the most recent injections in the pen memory, the insulin industry in some countries is moving away from durable pens in favor of disposables. In the pens that store data, it is not possible to download long-term data to study it in conjunction with blood glucose data. While others have speculated on so-called “smart pen” devices that incorporate wireless communication, for example “the Smart Insulin Pen” by John Walsh, P. A., C.D.E. (see, for example, http://www.diabetesnet.com/diabetes_technology/smart_pen.php), these are complex devices that are not consistent with the disposable pen model being adopted by the insulin companies. Finally, the regulatory pathway for approval of new pen devices is a long and expensive process.

Recognizing the shortcomings of the conventional insulin pens, applicants have invented various embodiments of a medical module that may be used not only with conventional insulin pens but also with any drug delivery pen. Various exemplary embodiments of the medical module are provided with useful features. For example, the modules are provided with dose sensing and wireless communication capabilities. The unit may be designed to work with various disposable drug delivery pens manufactured by the different insulin companies. The unit may be used in conjunction with pen devices for delivering medications other than insulin, such as, for example, growth hormone, GLP-1 analogs, Symlin, biologic molecules, and other injected biopharmaceuticals.

In the exemplary embodiments, the medical module is preferably a small, low profile, lightweight device that attaches to a disposable or reusable drug delivery device (e.g., an insulin pen) and measures the amount of drug (e.g., insulin) that is injected. The size and weight of such unit make it acceptable to carry the device attached to the pen in a pocket or purse, in the same way a user would carry a stand-alone pen. Preferably, the device does not impede normal functions of the drug delivery device, including turning the dosing dial, viewing the selected dose in the dose window, and pressing on the injection button to deliver a dose. After attaching the medical module, it does not add more steps to the process of using a drug delivery device during typical injections. The unit also records the amount of drug, such as, for example, insulin and date and time of the injection in memory, and may transmit the data to a data management unit for review by healthcare practitioners. In one preferred embodiment, the data management unit may include a paired analyte meter (e.g., a glucose meter which may be a non-continuous glucose meter or continuous glucose sensing meter) that receives or transmits data when the two devices are in range of each other. In such embodiment, the meter (not shown) keeps track of the drug dosing history, along with analyte (e.g., blood glucose values) for retrospective analysis by the patient and HCP. The device helps patients remember if they have taken their prescribed drug such as, for example, insulin, and may reduce the number of missed boluses, a key factor influencing HbA1c. The device also has several features that guide the user in the proper use of the drug delivery device, improving accuracy and reducing the burden of the HCP to train patients on insulin pen therapy. While the exemplary embodiments utilize a glucose sensor meter in the form of a data management unit, other types of analyte sensors may be used in conjunction with the module for the delivery of the appropriate injectable fluids such as, for example, growth hormone, GLP-1 analogs, Symlin, biologic molecules, and other injectable biopharmaceuticals.

First Type of Medical Module

As shown inFIG. 1, the exemplary module102includes a housing108that extends along longitudinal axis L1from a first end132to a second end180to define at least a portion142of a hollow bore109. The hollow bore109is adapted to be coupled to a drug delivery pen in one operative mode and to be separated from the pen in another operative mode. Upon separation from the pen, the module is no longer coupled to the actuation mechanism of the pen and in fact is lacking in an actuation mechanism, e.g., a plunger, push rod, or the like, such that an internal surface of the hollow bore is exposed to the ambient environment so as to be visible to an ordinary observer or user. Portion142is configured for attachment over an actuation unit100of a drug delivery device124or224(e.g., an insulin pen), shown here inFIGS. 3 and 6B. Housing108includes a first and second extension portions130and134that circumscribes about second axis L2to define at least a portion of a hollow bore109, locator tangs136and184(which are offset longitudinal with respect to each other along axis L2, dosage sensor114, locator forks152aand152bwith follower portion140that may reciprocate longitudinally along a longitudinal axis L1. The follower portion140is physically or directly connected to the dosage sensor114. In one embodiment, each of extensions130and134extends in a generally circular path about axis L2of about 30 degrees. Where greater security of engagement between the extensions and the pen is needed, each of extensions130and130may be increased to define any ranges from generally 30 degrees to generally 250 degrees (or even 360 degrees to provide for a continuous bore as illustrated inFIG. 8) about axis L2.

FIG. 2shows the back of the module102illustrated inFIG. 1.FIG. 3illustrates module102as part of a conventional drug delivery pen prior to assembly of the two components.

Referring toFIG. 1, follower portion140is configured to be physically connected directly to sensor114and permitted to rotate about its own axis. A power source176is also provided in a location preferably spaced apart from dosage sensor114(FIG. 5). A microcontroller, depicted here as controller board170inFIG. 5, is coupled to both sensor114and power source176to allow for a determination of position, movements or even direction of movement of a dosage selector120(seeFIGS. 2 and 3).

FIG. 5shows module102with the top housing removed to reveal the internal components. In particular,FIG. 5shows the location of longitudinal member154and locator forks152aand152bprior to injection with follower154extended to a selected dosage. Module102includes housing108, battery176, microprocessor circuit board170, dosage sensor114, and longitudinal member154. Dosage sensor114is used to measure the injected dose. Longitudinal member154moves parallel to the longitudinal axis L2of the pen, tracking with dosage selector120as it moves in and out with actuation shaft190of drug delivery pen102. Electrical circuit components (not shown due to placement of components in the drawings) are provided on board170such as, for example, microprocessor, microcontroller, analog-to-digital converter, speaker, display, memory, display driver, user interface driver, transmitter, receiver or transmitter-receiver (e.g., a wireless transceiver using infrared light, radio-frequency, or optical waves) and antenna to send and receive wireless signals to and from the meter, process input from the sensor, turn the device on and off, put the device into sleep mode, wake the device up, regulate power from battery176, and store and retrieve information to and from memory, as examples. Dosage sensor114is preferably a linear potentiometer and is used to measure the position of dosage selector120for determining the size of the bolus injected by the user. Sensor114is electrically coupled to an analog-to-digital converter, which is coupled to microprocessor board170to provide data on the position of dosage selector120and dosage actuator116. A micro-switch is provided at a position proximate housing end132to provide an indication of drug delivery upon button116being fully depressed to push shaft190towards cartridge122. Other sensors that may be used with the exemplary embodiments include rotational potentiometers, linear, or rotational encoders. Linear potentiometers are preferred in the operational prototypes built by applicants. However, the embodiments described herein may utilize means for determining displacement of a dosage selector of a drug delivery pen in which the means include a follower, longitudinal member, and a dosage sensor (which may include rotary potentiometer, linear potentiometer, capacitive displacement sensor, optical displacement sensor, magnetic displacement sensor, encoder type displacement sensor, or combinations and equivalents thereof) and equivalents to these components described herein. In the embodiment ofFIG. 1, the drug delivery pen may be a NovoLog® Flex-Pen manufactured by Novo Nordisk.

Second Type of Module

Recognizing that different drug delivery devices (e.g., insulin pens) may require alternative coupling technique, applicants have provided for an alternative that is designed to be inserted over one end of drug delivery device124or224rather than being attached from the side as in the prior embodiment. As with the first module type, a hollow bore of the module is adapted to be coupled to a drug delivery pen in one operative mode and to be separated from the pen in another operative mode. Upon separation from the pen, the module is no longer coupled to the actuation mechanism of the pen and in fact is lacking in an actuation mechanism, e.g., a plunger, push rod, or the like, such that an internal surface of the hollow bore is exposed to the ambient environment so as to be visible to an ordinary observer or user.

Referring toFIGS. 6A and 6B, module202is provided with housing209. Module202is provided with casing208that extends along longitudinal axis L1so that the casing208covers the outer surface of housing209. That is, casing208includes three wall surfaces that together with outer surface210of housing209provides for an enclosure of certain components. Casing208encloses circuit board270(seeFIG. 6D), sensor214(which includes a sensor slider215) and power supply276which are disposed on top of outer surface210of housing209. Power supply276is accessible through power supply compartment door provided on casing208. Because casing208is disposed over outer surface210of housing209, casing208is located asymmetrically with respect to longitudinal axis L2of housing209. To further reduce the offset profile of casing208, power supply276may be located proximate knob278instead of inside casing208.

Referring back toFIG. 6A, housing209extends from a first end232to second end280along longitudinal axis L2to define at least a portion of a hollow bore248. Coupled to housing209is a240, with knob278disposed about aperture252. Both of follower portion240and knob278are preferably continuous through-bores that are in alignment with bore248. Bore248is configured to allow actuation unit200of drug delivery pen224(seeFIG. 6B) to be slipped into bore248until actuation button216of pen224protrudes through opening252. In the preferred embodiment ofFIG. 6A, bore248is a through-bore which is contiguous with the bore of rotatable knob278and continuous surface210of housing209defines a generally tubular member. The knob278is physically coupled to the follower portion240, and the follower portion240is directly and physically connected to slider215of sensor214via longitudinal member254such that movement of the knob278results in corresponding proportional movements of follower240and slider215. To allow for visual inspection of printed indicia on drug delivery pen200or to allow for reading of the dose display218, a portion of housing209is preferably substantially transparent.

Applicants have recognized that, on certain conventional insulin pens, there are provided at least a raised ridge210b, shown, for example, inFIG. 7D. Applicants have recognized that raised ridge210bof such pens may be used to provide a positive coupling between unit102and the drug delivery pen. Specifically, unit202may be provided with a recessed groove on the inner surface of housing209that is in a mating arrangement with raised ridge210bto align unit202and prevent the rotation of unit202with respect to pen124.

To reduce the profile of unit202, applicants have utilized a sliding potentiometer configuration shown here inFIG. 6D. In this embodiment, a slider215is connected to longitudinal member254, which is connected to follower portion240. Longitudinal member254is provided with slider fingers294aand294b, which are used to retain a slider215. Follower240may be coupled to a dosage selector220by a suitable coupling arrangement, such as, for example, via a slip fit coupling with ring-like member interposed between follower240and the dosage selector or an arrangement adapted from the arrangement shown inFIG. 7E. In the adaptation ofFIG. 7E, follower240is coupled to a capture ring244via a groove retention mechanism that includes groove244don follower member240and corresponding ridge244con capture ring244. Capture ring244may include longitudinal slits244athat extend along longitudinal axis L2. Longitudinal slits244aprovide flexibility in the diameter of capture ring244which allow inner undulating surfaces244bof capture ring244to frictionally couple to dosage selector220(of pen224) via raised ribs221. Undulating surfaces244bmay be configured to allow for a taper towards axis L2to ensure little or no interference with ribs221when they first engage undulation244bbut with frictional engagement upon full insertion. Capture ring244may be provided with external splines or teeth245athat are in engagement with internal splines or teeth245bof rotatable knob278. Rotatable knob278is provided with a through opening252to allow actuation button216of pen202to protrude through such opening252for engagement by the user.

It should be noted that rotatable knob278disengages from capture ring244during injection so that the knob does not rotate under the user's thumb while drug is being delivered, i.e., during the injection. After injecting, teeth245are-engage with teeth245b, allowing the user to dial in a new dose on the pen. Knob278, however, may need to be rotated slightly before the teeth re-engage if they are not properly lined up after the injection.

Referring toFIG. 6D, longitudinal member254may be configured to slide axially along axis L2as knob278is moved axially by rotating knob278about axis L2. In this figure, slider215is shown positioned proximately mid-way on potentiometer tracks293. As knob278is rotated to translate knob278along axis L2, capture ring244is constrained to also rotate, which causes the rotational motion of capture ring244to be transferred to dosage selector220, which then causes dosage selector220to also rotate and translate. Since any rotary motion of selector220will results in axial movement along axis L2, capture ring244, follower240, and knob278are constrained to move in the same manner as dosage selector220(axially for follower240, and both axially and rotationally for capture ring244and knob278). Hence, movements of the dosage selector220are determined via the potentiometer as proportional to a dosage quantity to be delivered or injected. In the preferred embodiments, potentiometer tracks293may be conductive polymer tracks or cerement tracks. In the embodiment ofFIG. 6B, the drug delivery pen may be a Lantus SoloStar insulin manufactured by Sanofi-Aventis.

InFIG. 6D, longitudinal member254is connected to a separator member255cwhich interacts with fingers269aof micro switch268to allow for a determination of a drug delivery event. Because fingers269aare normally not in contact with conductive tracks269b, switch268is normally opened whenever button216is not depressed fully (e.g., during a dosage selection or adjustment). Upon button216being fully depressed in direction2, longitudinal member254and separator255care constrained to move along longitudinal axis L1until spring255ais fully compressed to abut against a stop surface (not shown) in casing208. As spring255aapproaches the stop surface, separator255clowers fingers269aof micro switch268onto conductive tracks269b, creating a closed-circuit. Movement of the button216in direction2separates fingers269awhereas movement in direction1causes the fingers269ato contact conductive tracks269band forming a closed-circuit, i.e., in the manner of a momentary switch.

Third Type of Module

Referring toFIGS. 7A and 7B, an alternative module204is provided with several distinct features from the previously described module202. Like module202, this module204has a housing209. Module204is also provided with casing208that extends along longitudinal axis L1so that the casing208covers the outer surface of housing209. That is, casing208includes three wall surfaces that together with the outer surface210of housing209provides for enclosure of certain components. Casing208encloses circuit board270(seeFIG. 8A), sensor214(which includes a sensor slider215) and power supply276which are disposed on top of outer surface210of housing209. Power supply276is accessible through power supply compartment door provided on casing208. Because casing208is disposed over outer surface210of housing209, casing208is located asymmetrically with respect to longitudinal axis L2of housing209. To further reduce the offset or asymmetric profile of casing208, power supply276may be located proximate knob278instead of inside casing208. As with the first and second module types, a hollow bore of the module is adapted to be coupled to a drug delivery pen in one operative mode and to be separated from the pen in another operative mode. Upon separation from the pen, the module is no longer coupled to the actuation mechanism of the pen and in fact is lacking in an actuation mechanism, e.g., a plunger, push rod, or the like, such that an internal surface of the hollow bore is exposed to the ambient environment so as to be visible to an ordinary observer or user. Housing209extends from a first end232to second end280along longitudinal axis L2to define at least a portion of a hollow bore248formed from continuous surface210of housing209. Continuous surface210is provided with a scallop portion211(FIGS. 7A and 7C) that is distinct from other embodiments. While a housing209can be formed from a substantially transparent or translucent material, such material can cause visual distortion of printed indicia on drug delivery pen224. As such, scalloped opening211allows for printed identification on drug delivery device224to be visible to the user once unit204has been coupled to pen224. Module204is coupled to drug delivery pen224by inserting bore248with scallop211closest to dosage selector220of pen224(FIGS. 1 and 1B). As module204is inserted onto pen224, a groove210aon module204(FIGS. 1 and 1B) is aligned with a raised ridge210bon pen224to fix module204rotationally with respect to pen224. In addition, a tang236may be used to engage to a recess in pen224.

Coupled to housing209are a follower portion240, and rotatable knob278. Both of follower portion240and knob278are preferably continuous through-bores that are in alignment with bore248. Bore248is configured to allow actuation unit200of drug delivery pen224(seeFIG. 10) to be slipped into bore248until actuation button216of pen224abuts with button251of module204. In the preferred embodiment ofFIG. 7A, bore248is a through bore which is contiguous with bore of rotatable knob278and continuous surface210of housing209defines a generally tubular member. As noted earlier, secondary-housing209is preferably formed from a substantially transparent or translucent material while casing208may be formed with any suitable color or combination of colors. As used herein, the actuation unit200of a drug delivery pen is that portion of the pen on which at least the dosage selector, actuator and actuation button are provided for attachment to a drug cartridge222.

Module204is coupled to drug delivery pen224by inserting bore248with scallop211closest to dosage selector220of pen224(FIG. 7D). As module204is inserted onto pen224, a groove210aon module204(FIG. 7A) is aligned with a raised ridge210bon pen224to fix module204rotationally with respect to pen224.

Referring toFIG. 8A, module204also utilizes a slider215on potentiometer tracks, which slider215is connected to longitudinal member254, which is connected to follower portion240. Longitudinal member254is provided with slider fingers294aand294b, which are used to retain a slider215(FIG. 8A) along with retention rods296(FIG. 8B) to ensure that the slider is constrained for translation along axis L1.

As shown inFIG. 7E, follower240is coupled to capture ring244via a retention system having groove244don follower member240and corresponding ridge244con capture ring244. Follower240and capture ring244can be coupled together such that capture ring244is rotatable around second longitudinal axis L2and that follower240does not rotate, but moves in a linear manner parallel to second longitudinal axis L2.

Capture ring244may include longitudinal slits244athat extend along longitudinal axis L2to provide flexibility in the magnitude of the diameter of capture ring244, which allows inner undulating surfaces244bof capture ring244to frictionally couple to raised ribs221of dosage selector220(of pen224). Inner undulating surfaces244bmay be configured to allow for a taper converging towards axis L2to ensure little or no interference when ribs221first engage undulation244byet with frictional engagement upon full insertion of module204into pen224. Capture ring244may be provided with external splines or teeth245athat are in engagement with internal splines or teeth245bof a coupling ring245. Coupling ring245can couple together rotatable knob278and capture ring244. The mechanical assembly of capture ring244, coupling ring245, and rotatable knob278causes dosage selector220to rotate as a result of a rotation of rotating knob278when the dosage selector220is frictionally engaged.

Actuation button251is also coupled to knob278so that button251of module202is in contact with pen button216once both components are assembled together. A spring246can be located on an outer surface of capture ring244and an inner surface of knob278. Spring246can be configured to bias coupling ring245against capture ring244such that when teeth245aare engaged, turning knob278causes dosage selector220to turn. During an injection, pressing button251can compress spring246, allowing coupling ring245to disengage from capture ring244. It should be noted that rotatable knob278disengages from capture ring244during actual injection so that the knob does not rotate under the user's thumb while drug is being delivered, i.e., dosage on the pen. Follower240can include a longitudinal member254, as illustrated inFIG. 7E. Longitudinal member can have a tubular structure where one end is coupled to a ring portion of the follower240. A hollow portion294cof the tubular structure is depicted inFIG. 7E. The other end of longitudinal member can have a protrusion plate294dand two slider fingers294aand294b.

Referring toFIG. 8A, longitudinal member254may be configured to slide axially along axis L2. Follower portion240is constrained to move with knob278as knob278is moved axially by rotating knob278about axis L2. As knob278is rotated, capture ring244is constrained to also rotate, which causes the rotational motion of capture ring244to be transferred to dosage selector220. Since any rotary motion of selector220will result in inward or outward axial movement along axis L2, capture ring244, follower240, and knob278are constrained to move in the same manner as dosage selector220(axially for follower240, and both axially and rotationally for capture ring244and knob278). Hence, movements of the dosage selector220are determined via a dosage sensor214as proportional to a dosage quantity to be delivered or injected. In the preferred embodiments, the dosage sensor, which provides dosage amount information, is a potentiometer. In the embodiment ofFIG. 7B, the drug delivery pen may be a Lantus SoloStar manufactured by Sanofi Aventis.

Referring toFIG. 8B, longitudinal member254is removed to show activation shaft297that was disposed inside longitudinal member254. Activation shaft297is connected to a separator member255c, which interacts with fingers269aof micro switch268. Hollow portion294cand protrusion plate294dcan be keyed to correspond to separator member255cso that separator member moves along axis L1when button251is depressed. Activation shaft297may be coupled with a spring255aand a setscrew255bfor adjustment of the position of separator255cwith respect to fingers269aof micro switch268. Because fingers269aare normally out of contact with conductive tracks269b, switch268is normally-open whenever button251is not depressed fully (e.g., during a dosage selection or adjustment). Upon button251being fully depressed, such as during a dosage injection, longitudinal member254, activation shaft297, and separator255care constrained to move along longitudinal axis L1until setscrew255babuts against retainer wall255d. As setscrew255bapproaches retainer wall255d, separator255clowers fingers269aof micro switch268onto conductive tracks269b, creating a closed circuit. Further movement of dosage button251causes hollow longitudinal member254to continue axially to take up any slack provided between an end of a rod portion of activation shaft and setscrew255b.

By virtue of the configurations described exemplarily herein, applicants have now been able to provide the means for determining the difference between either or both of a dosage delivery event and duration of such dosage delivery or injection event. Specifically, where a user is merely rotating knob278to thereby move knob278longitudinally along axis L2in either direction to select dosages, there is no contact of fingers269aof switch268and hence no determination that a dosage event is taking place. Except for a determination that a dosage selection is being made, no recording is made in the memory of processor board270regarding a dosage delivery. Only upon the full depression of button251would there be contact of fingers269awith tracks269b, (FIGS. 8A and 8B) triggering a determination that dosage delivery is taking place. In an embodiment, the electronics can be configured to go into “sleep” mode, until button251is depressed, which reduces the power consumption of the module. As used herein, the “sleep” mode is one in which all functionalities of the module are at minimal or virtually zero power consumption but which does not require a system boot up in the event that the pen is taken out of sleep mode.

It should be noted that the micro-switch268also enables tracking of the injection start point and the injection end point, so the volume of the injection can be calculated, even if the user does not press the injector button all the way to the zero dosage position. While the ability to determine when a dosage delivery has been made is valuable to a user in managing diabetes, applicants believe that it is the ability to determine and confirm the duration of such dosage delivery for later analysis with a compliance regiment that is a step forward in the art of diabetes management. That is, where a patient is injecting insulin per a protocol as prescribed by a health care provider, such patient may not be in full compliance if the patient fails to deliver a complete prescribed dosage, which typically requires fully depressing button251for four (4) to ten (10) seconds. By recording the dosage, time and duration in memory of processor board270for transfer to a health care provider's computer, the health care provider is able to take steps, after review of data or even in real-time, to ensure that full compliance of the prescribed protocol is followed. In the preferred embodiments, a warning or reminder to the patient on proper pen usage technique can be displayed as a message on the data management unit, which in one embodiment includes a glucose meter. Thus, the means for determining one or more of dosage delivery or duration of dosage delivery of a drug delivery pen include, follower240, longitudinal member254, spring255a, separator269a, switch268, a processor coupled to switch268, in which processor is programmed to operate in the manner described herein, and equivalents to these components.

Fourth Type of Module

Recognizing that different drug delivery devices (e.g., insulin pens) may be required based on user preferences, applicants have provided for an alternative type of module402, as illustrated inFIG. 9A, which is usable with a drug delivery pen, as illustrated inFIG. 9B. In this embodiment, applicants have provided for an alternative that is designed to further reduce the offset or asymmetric profile. Additionally, applicants have provided for an alternative that has a mechanism for easily changing the batteries. Add-on module402can include a primary module housing408, a secondary module housing409, a rotatable knob478, a button451, and a slot451a. A power supply can be in the form of a disk shape (e.g., coin cell battery) similar in shape to a button451. The battery can be disposed proximate to button451in a stacking relationship. Slot451acan be used to rotate button451using a coin or screwdriver to easily remove button451so that the battery can be changed.

Other Variations of the Add-On Module

FIG. 10Aillustrates another embodiment of a module502that is similar to module102. Add-on module502does not have a first and second extension portions like module102. Instead, module502has a housing that wraps around the drug delivery pen. The housing of module502has two windows519aand519bfor allowing the user to view display window and written indicia on the pen. Add-on module502includes a button551and a slot551a. A power supply can be in the form of a disk shape (e.g., coin cell battery) similar in shape to a button551. The battery can be disposed proximate to button551in a stacking relationship. Slot551acan be used to rotate button451using a coin or screw driver to easily remove button551so that the battery can be changed.

FIG. 10Billustrates another embodiment of a module602that is similar to module102. Add-on module602includes a button651and a slot651athat are similar to module502.

FIG. 10Cillustrates another embodiment of a module702that is similar to module204. In contrast to previous embodiments, module702has a housing that is symmetrical with respect to a longitudinal axis that extends along the pen. The housing of module702has a window719for allowing the user to view display window on the pen.

Operation of the Exemplary Embodiments

In use, a user would couple (e.g., snap-on, slide on, close a clam-shell) the medical module (102,202,204,402,502,602, or702) over actuation end100(or200) of a drug delivery pen124(or224), as shown herein the figures. Once the medical module (102,202,204,402,502,602, or702) has been coupled to drug delivery pen124(or224), turning dosage selector120(or rotating knob278) allows the user to dial in a dosage for injection. The selected dosage appears in dosage indicator window118(or218) of the pen124or224. As dosage selector120rotates, it extends shaft190within drug delivery pen124(or224), illustrated inFIGS. 5 and 6D, causing longitudinal member154(or254) to extend as well. Similarly, as knob278rotates, it extends longitudinal member254within the primary module housing208, as illustrated inFIG. 8A. The amount of insulin to be injected is proportional to the extension of shaft190(FIG. 5) of pen124and longitudinal member154, which is measured by dosage sensor114. Similarly, the amount of insulin to be injected is proportional to the extension of follower240of module202and longitudinal member254, which is measured by dosage sensor214. Dosage selector120(or knob278) may be rotated in either direction, increasing or decreasing the selected dosage.

A suitable needle (not shown) can be attached to the insulin cartridge122or222. Before injecting, the user primes drug delivery pen124or224by ejecting a small dose (typically 2 Units) before inserting a needle subcutaneously. Priming drug delivery pen124or224eliminates bubbles. While priming, drug delivery pen124or224should be held with needle pointing upwards. Medical module102may distinguish between primes and injections by two exemplary techniques: (1) it may determine via an inertial or acceleration sensor disposed in the housing of the add-on module if drug delivery pen124or224is held with needle pointing upward (in relation to the ground) during an injection, and (2) it may use software to determine if one or more small doses of approximately 2 Units are followed by a larger dose. In some cases, a separate glucose meter may ask the user to confirm whether a dose was a prime or an injection. In an embodiment, the inertial sensor can also be used to wake up the device if it is in sleep mode when the device is picked up by the user. In the dosing history menu on the glucose meter (not shown), it is possible for the user to toggle entries between prime and injection. As an example, the meter can display primes by indicating with the symbol “*” (for example) which injections were preceded by a prime. Applicant believes that this allows the displaying of as much information as possible on one screen on the meter without confusing the user by showing all the primes and injection doses together in one list.

After dialing in the desired dose, the injection is performed by inserting the needle into the skin and with the user's thumb fully depressing actuation button116of pen124(for module102), button216of pen224, or button251(for module202). Once the actuation button is fully depressed, the button must be held down for a predetermined period of time for the selected dosage to be fully injected. As provided in the means for determining dosage injection event and duration thereof, the add-on module records such an event and the duration of the event into its memory. The user may perform this sequence until the cartridge222is depleted.

After insulin cartridge222is depleted, module102(202or204) is removed from disposable drug delivery pen124(or224), disposable drug delivery pen124or224(e.g., an insulin pen) is thrown away, and module102is re-attached to a new disposable drug delivery device124or224(e.g., an insulin pen). Alternatively, where the user is using a reusable pen, the empty drug cartridge could be thrown away and replaced with a new cartridge attached to the actuation portion of the reusable pen.

As noted earlier, the single glucose meter may communicate with multiple medical modules. For example, glucose meter may communicate with a medical module (102,202,204,402,502,602, or702) attached to a rapid acting insulin drug delivery pen and another unit (102,202,204,402,502,602, or702) with a long acting insulin drug delivery pen. Medical modules (102,202,204,402,502,602, or702) may be color coded to match the color of drug delivery pens124or224, identifying the type of insulin that it contains. This feature will help prevent accidental injections of the wrong type of insulin. In an embodiment, the module can be configured to attach to a specific type of pen housing in order to identify the type of insulin. In this embodiment the insulin pen manufacturer provides different type of pen housing shapes for specific types of insulin.

While some features have been described, other variations on the exemplary embodiments may be utilized in various combinations. For example, instead of a potentiometer, the add-on modules may use an encoder to measure angular position and rotation of dosage selector. A switch may be used with the encoder to detect when the user presses on dosage actuation button of the add-on module (102,202,204,402,502,602, or702) to inject a drug, such as, for example, insulin, and allows for differentiation between dosage adjustments and injections. Such switch also detects how long the user continues to press on the dosage actuation button after injecting an insulin shot, as described earlier. In another example, when the switch is activated and after the encoder determines that dosage selector dial has returned to the zero position, the add-on module (102,202,204,402,502,602, or702) may communicate this information to the blood glucose meter to initiate a timer on the meter that counts down the period of time that the user should keep the dial depressed. If the user releases pressure on the switch prematurely, a warning may be announced or displayed on the blood glucose meter. Alternatively or in addition, a small display or LEDs on the snap-on pen module (102,202,204,402,502,602, or702) may be used to cue the user as to how long to press on the dial. It is noted, however, that a display is not absolutely necessary—the device could just track the time that the button is depressed and display a message/warning on the meter if the user does not hold down the button for a sufficient amount of time. The switch may also be configured to work with sensors other than encoders, for example the linear potentiometer as shown exemplarily inFIGS. 1-8. Medical module (102,202,204,402,502,602, or702)102may include various features that guide users in the proper use of drug delivery pens124or224. For example, medical module (102,202,204,402,502,602, or702) can: alert the user if they have not primed drug delivery pen124or224using the inertial sensor; alert the user if a mixing step has not been performed (applicable to mixed insulins) using the inertial sensor; warn the user if the injection is incomplete (i.e., dosage delivery button is not pressed all the way to zero); provide a timer that reminds the user to hold dosage delivery button116down for several seconds during an injection; keep track of remaining insulin in drug delivery pen124or224; remind user when it is time to inject; alert the user if injections have been missed or duplicated; alert the user if insulin is about to expire.

In addition, medical module (102,202,204,402,502,602, or702) may include a micro switch in module housing108to allow for activation of certain features. For example, the insertion of drug delivery pen124or224into medical module (102,202,204,402,502,602, or702) triggers the micro switch. Triggering the micro switch serves two purposes: first, it signals when a new drug delivery pen124or224is inserted, which allows medical module (102,202,204,402,502,602, or702) to track how much insulin is left in drug delivery pen124or224; and second, it ensures that drug delivery pen124or224is inserted correctly, and is properly aligned with medical module.

Another feature that may be included in module is a technique for distinguishing a priming dose from a dose that is injected into the user. For example, a gravity or inertial sensor may be used to determine if the device is pointing upwards when dial3is pressed, indicating a priming shot since the device is held in an inverted position when purging bubbles. The add-on module is able to distinguish priming shots from actual drug delivery. For example, priming shots are typically two units or less, making them distinguishable from larger injected shots, and a priming shot will typically be followed by an injected shot, a pattern that may be distinguished in software. Similarly, it is useful to be able to distinguish between dosage size adjustments in which the user turns the dial backwards and/or forwards to dial in a specific dosage vs. movement of the dial position from the user injecting a shot. This is detectable by the microcontroller via the dosage sensor as well, since injections into the user should end with the dial returned to the initial, or home position, whereas adjustments of the dial to modify the dosage typically occur when the dial is set at a larger dosage and do not terminate in the initial, or home position of the dial.

Several features may be utilized to reduce inaccuracies in the use of insulin pens. These include missing injections, duplicating injections, and improper priming. Improper priming is especially problematic if a needle (not shown) was left on between doses, allowing air to enter drug cartridge122. Some insulins, such as 70/30 pre-mix, must be mixed prior to injection. Neglecting to mix or improperly mixing 70/30 pre-mix before injection is a source of inaccuracy. Dosage delivery button116should be held for approximately 6 seconds during an injection to ensure the entire dose enters the body. Not holding dosage delivery button116long enough results in a partial dose. Medical module alerts the user to these inaccuracies and thus helps to reduce them.

As mentioned previously, the medical module (102,202,204,402,502,602, or702) may be used to measure insulin doses and transfer that information to a data management unit, which may be a glucose meter or a suitable data communication unit such as a mobile phone, home computer, mobile computer, server, monitoring network or even an insulin pump or combined insulin pump and controller or the like. The information that is transferred from medical module to the data management unit may be used to help master the use of drug delivery pen124or224. Large potential sources of inaccuracy in the use of drug delivery pen124or224are missed doses and double doses. Medical module, as embodied herein, may help eliminate these sources of error by reminding the user of their dosing history. The complete dosing history (including doses and time and date the doses were delivered) may be made available to the user by selecting this option from the data management unit's menu. In addition, by having the most recent dosing information (time and amount) on a meter's display when the data management unit turns on, the user will immediately see if they have forgotten an injection every time they take a blood glucose measurement. In the same way that a data management unit may be used to alert a user when it's time to test blood glucose, the data management unit may also alert the user when to take insulin, or if an insulin injection has been missed. This information may also be displayed when the data management unit turns on.

Another source of inaccuracy when using drug delivery pens124or224is improper priming technique (or failing to prime altogether). The purpose of priming (sometimes called a test injection) is to remove air bubbles from drug cartridge122and needle, which would reduce the volume of an injection. Drug delivery pen124or224should be held vertically during priming so bubbles rise to the top of drug cartridge122(the end closest needle) and may be expelled by a priming dose. The priming is successful if the user sees a drop of insulin appear at the needle tip. If the user does not see a drop of insulin, the priming step is repeated. An inertial sensor is disposed in the module housing or located on the processor board170or270to detect if drug delivery pen124or224is held vertically during priming, and this information may be sent wirelessly to the data management unit. Low cost microelectromechanical systems (MEMS) inertial sensor chips are widely available, accurate, low cost, and small in size. Preferred inertial sensor may include Analog Devices model ADXL322 accelerometer (available at http://www.analog.com/en/mems-and-sensors/imems-accelerometers/ADXL322/products/product.html#pricing). The data management unit may remind the user to hold drug delivery pen124or224vertically when priming, if they are not doing so. In addition, if the user skips the priming step altogether, this will be apparent from the information collected by medical module102,202, or204, and a visual or auditory warning, reminder, and/or instructions may be given to the user by the add-on module or the data management unit.

The inertial sensor is also utilized to determine if the user is performing the proper mixing technique before injecting insulin, another source of error in using drug delivery pen124or224. Some insulins must be mixed prior to use, such as 70/30 pre-mixed insulin. Mixing typically involves moving drug delivery pen124or224from straight up to straight down ten times, an action that is easily detectable by an inertial sensor (located in an attached medical module102,202, or204. A message may be displayed on the data management unit to remind the patient how to mix their insulin if they are using insulin that requires mixing prior to use.

Another source of error related to priming is that of neglecting to remove and dispose of needles after each injection. The meter, in one embodiment, would provide a display to generate a reminder stating that the needle should be removed with every use. Alternatively, the speaker mounted in the add-on module can be utilized to prompt the user with tones or prestored phrases configured for specific geographical areas (e.g., German for modules distributed in Germany, French for modules distributed in France and so on). Additionally, the speaker in the add-on module may be configured to allow a user to locate a misplaced pen and module. Specifically, the add-on module may respond to an inquiry signal from a data management unit (or any electronic devices paired to the add-on module) to cause the speaker in the add-on module to emit tones or beeps in the event that the user has misplaced the pen and module. This method also can be used to confirm that a particular module is paired with a particular data management unit such as a glucose meter.

When injecting insulin with drug delivery pen124or224, it is important to hold down on dosage delivery button116with needle inserted for approximately six seconds, to ensure that the entire dose is delivered below the skin. The optimal amount of time is usually spelled out in drug delivery pen124or224user's manual. A message may be displayed on either or both of the add-on module or the data management unit, reminding the user of proper technique if they are releasing dosage delivery button116,216or251prematurely. The data management unit or the add-on module may display a countdown timer or emit a countdown tone or signals, initiated when dosage delivery button116is first pressed, letting the user know when they should release dosage delivery button116.

Other pen-related usage reminders, such as the amount of time a pen may be used after removed from refrigeration, also may be incorporated into the smart pen module and displayed on the blood glucose meter as an aide to the user. To track the time a particular pen has been in use, the user would need to indicate the initiation of a new pen on the meter. In such embodiment, a switch is provided in the hollow bore of the smart pen module that is activated when it is attached to a pen, signaling the initiation of a new pen. The user may be asked to confirm on the meter when a new pen is initiated by pressing a button and possibly entering some information, such as the amount of insulin in the new pen.

In the examples given above, the add-on module (102,202,204,402,502,602, or702) is provided with a transceiver to allow receipt and transmission of information collected by the smart pen module to a cell phone or computer for easy look up or prominent display.

These features described and illustrated may be incorporated into a re-usable pen, in addition to a conventional disposable pen.

To our knowledge, no other device has sought to address the problems recognized here by applicants, with the exception of conventional digital insulin pens that display the last few injection amounts.

Several prototypes have been built that measure the amount of each dose and transmit this information to a meter for display. During evaluation of the prototypes, it was recognized by applicants that it would be useful to have the device communicate with multiple pens, since users often use one pen for long acting insulin and a separate pen for rapid acting insulin. In addition, some patients use more than one pen of the same type of insulin, placing them in different convenient locations (for example, at home, at work, in the car, etc.). Hence, applicants have realized that multiple modules may communicate with the data management unit (e.g., analyte meter, infusion pump or controller) for each of these pens to ensure that all insulin injections are captured. Also, it was further realized by applicants that the modules may be color-coded so that they would match the color of the drug delivery pen they are designed to work with. This feature is believed to be useful to users because insulin companies use the same pen to deliver different insulins, and they use color-coding to help the users distinguish between different pens. The modules may alert the user via a message, visual warning, or alarm on the add-on module(s) or meter as to the type of insulin they are injecting, helping them catch a potential error in which they might be injecting the wrong insulin—an error that may cause hypoglycemia or hyperglycemia.