Patent Publication Number: US-2020284637-A1

Title: System and method for capturing dose information

Description:
This application is a divisional of U.S. application Ser. No. 14/485,749, filed Sep. 14, 2014, the entirety of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to systems and methods for capturing the volume of medication delivered by a syringe or other medication delivery device. In particular, the present invention relates to systems and methods for utilizing magnetic position sensing such as Hall-effect sensing and magnetoresistive (MR) sensing, Micro Electro Mechanical Systems (MEMS) flow sensing, and the like in connection with various medication delivery devices and components to capture medication dose delivery information. 
     BACKGROUND OF THE INVENTION 
     Diabetes is a group of diseases marked by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. There are 25.8 million people in the United States, or 8.3% of the population, who have diabetes. The total prevalence of diabetes has increased 13.5% since the 2005-2007 time period. Diabetes can lead to serious complications and premature death, but there are well-known products available for people with diabetes to help control the disease and lower the risk of complications. Chronic hyperglycemia leads to serious sometimes irreversible complications including renal failure, peripheral neuropathy, retinopathy, and vascular system complications. 
     Treatment options for people with diabetes include specialized diets, oral medications and/or insulin therapy. The primary goal for diabetes treatment is to control the patient&#39;s blood glucose (sugar) level in order to increase the chances of a complication-free life. 
     Idealized diabetes therapy would include continuous monitoring of blood glucose levels, data capture for insulin dosing, dietary intake, such as carbohydrate estimation, activity tracking, stress levels, and other factors. By continuously monitoring, healthcare professionals can maximize the effectiveness of the treatment regimen for each patient. Unfortunately, conventional diabetes treatments, including multiple daily injections (MDI), insulin pens, patch pumps and insulin pumps, do not adequately record information on medication doses delivered to the patient to provide feedback to the doctor. Accordingly, the conventional feedback loop between doctors and patients is less frequent, and based mainly on qualitative assessments between the doctor and patient. Accordingly, there is a need to enhance medication delivery devices and methods to add informatics such as dose delivery capture, to provide enhanced feedback to healthcare professionals to improve diabetes therapy. 
     In order to properly diagnose and treat diabetes mellitus (DM) the patient and/or Health Care Provider (HCP) needs to evaluate the short-term, daily records for (1) insulin dosing, (2) oral medications, (3) Blood Glucose Measurement (BGM), and (4) carbohydrate intake. These data are obtained from different sources, such as the setting on an insulin pen, the episodic reading from a BGM meter, and the estimate of carbohydrates in a meal all determined and transposed by the patient into a logbook or diary. This method of recording data is extremely tedious and prone to errors and omissions. Even in the best case scenario, when the historical records are complete, the insight that can be obtained is limited without transposing the hand written data to software that can reconfigure the data to evaluate trends and support therapeutic modifications. As a result the majority of patients do not properly maintain their logbook, which reduces the ability of the patient and the doctor to properly diagnose the disease, which can ultimately result in poor adherence to therapy and poor glycemic control. Accordingly, a system is required to automatically capture, store, transfer, and enable optimal assessment of all the data necessary for the proper diagnosis and treatment of Diabetes Mellitus. 
     U.S. Pat. No. 8,613,719 describes a monitor that can be attached to the patch pen, which can sense and wirelessly transmit the time of each delivery event. A flag, such as a magnet, is placed on the movable linkage within the patch pen, and a sensor within the monitor attachment detects the proximity of the magnet at the end of the linkage travel, that is, at the end of the delivery cycle. 
     SUMMARY OF THE INVENTION 
     The above described disadvantages are overcome or minimized and the above and other advantages are realized by embodiments of the present invention. Exemplary embodiments of the present invention provide a device for capturing delivered dose information. The device includes a medication delivery device, a dose information capture device adapted to be attached to the medication delivery device, and a sensor element adapted to be attached to the medication delivery device. The sensor element comprises at least one of either a magnet, preferably a permanent magnet, although a non-permanent magnet could be used, and at least one a ferrous element, and attaches to the medication delivery device on a dose delivery mechanism of the medication delivery device. The dose information capture device includes a magnetic position sensor adapted to detect a position of the sensor element. 
     Accordingly, embodiments of the present invention provide a device that senses a delivered dose by magnetic position sensing. Magnetic position sensing is accomplished by Hall-effect sensors, magnetoresistive sensors, or any other suitable device. Various embodiments may sense linear translation, rotational movement, flow, or medication level within an insulin vial or reservoir. Magnetic position sensing determines linear or rotational movement of the mechanical linkage or mechanization that correlates with the dose to be delivered in an insulin pen or other drug delivery device, as will be described herein. In other embodiments magnetic position sensing is utilized to determine the level of fluid in a vessel, such as by linear translation or change in position of a magnet floating on a top surface of insulin. Flow sensing, particularly MEMS flow sensors, include coriolis, capacitance, and thermal Time of Flight (ToF) sensors used to determine the volume of drug delivered from a pen, syringe or other drug delivery device. Capacitance sensing is preferably used to measure and determine the level of liquid, such as insulin, in a vessel such as an insulin vial. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other exemplary features and advantages of certain exemplary embodiments of the present invention will become more apparent from the following description of certain exemplary embodiments thereof when taken in conjunction with the accompanying drawings, in which: 
         FIG. 1  illustrates an informatically enabled vial sleeve according to an exemplary embodiment of the present invention; 
         FIG. 2A  illustrates flux density over distance in a Hall-effect sensor and magnet arrangement utilized with an exemplary embodiment of the present invention; 
         FIG. 2B  illustrates a substantially linear output voltage over flux density curve for a Hall-effect sensor arrangement utilized with an exemplary embodiment of the present invention; 
         FIG. 3  illustrates an informatically enabled vial sleeve according to an exemplary embodiment of the present invention; 
         FIG. 4  illustrates an informatically enabled vial sleeve according to another exemplary embodiment of the present invention; 
         FIG. 5  illustrates a pen cap and flow sensor according to an exemplary embodiment of the present invention; 
         FIG. 6  illustrates an informatically enabled attachment for a reusable or disposable pen according to an exemplary embodiment of the present invention; 
         FIG. 7  illustrates a multi-pole magnetic ring and Hall-effect sensor arrangement for use with the attachment illustrated in  FIG. 6 ; 
         FIG. 8  illustrates a fixed dose pen 
         FIG. 9  is another illustration of either an adjustable or fixed dose pen. 
         FIGS. 10 and 11  illustrate embodiments of informatically enabled mechanical patch pens according to exemplary embodiments of the invention; 
         FIG. 12  illustrates an informatically enabled pen case according to an exemplary embodiment of the present invention; 
         FIG. 13  illustrates an informatically enabled pen case according to another exemplary embodiment of the present invention; 
         FIG. 14  illustrates an informatically enabled syringe sleeve according to another exemplary embodiment of the present invention; 
         FIG. 15  illustrates an informatically enabled vial sleeve utilizing capacitance sensing according to another exemplary embodiment of the present invention; 
         FIG. 16  illustrates an informatically enabled vial sleeve, according to another exemplary embodiment of the present invention; 
         FIG. 17  illustrates another informatically enabled vial sleeve, according to another exemplary embodiment of the present invention; 
         FIGS. 18A and 18B  illustrate a linear magnetic position sensing arrangement attached externally to a syringe according to an exemplary embodiment of the invention; 
         FIG. 19A-19D  illustrate an informatically enabled injection port; 
         FIG. 20  illustrates a wireless communication system including an informatically enabled medicine delivery device according to an exemplary embodiment of the present invention; 
         FIG. 21  illustrates a system for identifying pen needles according to an exemplary embodiment of the invention; 
         FIG. 22  illustrates another system for identifying pen needles according to an exemplary embodiment of the invention; 
         FIG. 23  illustrates another system for identifying pen needles according to an exemplary embodiment of the invention; and 
         FIG. 24  illustrates yet another system for identifying pen needles according to an exemplary embodiment of the invention; 
     
    
    
     Throughout the figures, like reference numbers will be understood to refer to like elements, features and structures. 
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     In the example provided below, insulin delivery is described. However, it should be understood that insulin delivery is merely exemplary, and any medicament delivery is contemplated to be within the scope of the invention. Informatics is defined herein as an interdisciplinary field primarily concerned with the analysis, collection, classification, manipulation, storage, retrieval, movement, and dissemination of information. 
     Exemplary embodiments of the present invention capture the amount or volume of medicament being delivered by either a syringe, insulin pen, or other drug delivery device. Several primary fields of technology, magnetic position sensing including Hall-effect sensing, magnetoresistive (MR) sensing, including anisotropic MR, MEMS flow sensing including thermal time of flight (ToF) sensing, micro-Coriolis and capacitive pressure sensing, are applied to various devices and device components to enable dose capture. MEMS capacitive pressure sensing uses Bernoulli&#39;s principle and/or the empirical Darcy-Weisbach equation are utilized to detect a change in pressure by changing the diameter of the conduit in the flow sensing element, and the pressure is measured using two capacitive MEMS pressure sensors located respectively in sections of conduit having different diameters. In the exemplary embodiments described herein, it should be understood that any type of MEMS flow sensing may be utilized in place of magnetic position sensing. It should be understood that embodiments of the present invention are not limited to Hall-effect sensing and MEMS flow sensing, but rather any suitable sensing technology is within the scope of the present invention. 
     Conventional Hall sensors are sensitive only to magnetic fields that are perpendicular to the chip surface, that is, one dimensional or ID. 3D Hall sensors advantageously also respond to magnetic fields parallel to the chip surface. The sensor chip has a separate sensor for each of the three magnetic axes, and converts the magnetic field data into absolute position information using a simple two pole magnet as the magnetic field source. For a linear sensing application, the 3D Hall sensor would be used in 2D mode. One advantage of this system for linear sensing is that it allows for larger separation between magnet source and sensor than standard ID Hall sensors. 
     A basic Anisotropic Magnetoresistive (AMR) sensor uses a single saturated-mode Wheatstone bridge, typically made from Permalloy (Ni—Fe alloy), that creates an output voltage with respect to the direction of the magnetic flux passing over the sensor surface. Thus it operates in saturation mode to avoid interference from stray magnetic fields and the magnetic field that it senses is across the face of the chip, contrasting with the perpendicular field of a Hall sensor. The AMR sensor creates an analog output voltage that varies with the direction of the magnetic flux passing over the chip surface. The minimum field required to put the AMR sensor into saturation mode is typically 50-80 gauss. A single element AMR sensor has a ±45° range of operation where voltage-to-angle output is linear. 
     Embodiments of the present invention preferably meet the following functional capabilities. First, embodiments of the present invention preferably electronically capture the amount of pharmaceutical injected and the time of the injection event. Second, they preferably provide a means of associating the captured injection event data with the type of pharmaceutical injected. Drug identification technology may be incorporated into embodiments of the present invention, and are described in U.S. Published Application Nos. 201210222468, 2012/0226447, and 2012/0226446, the entire contents of each of which are hereby incorporated by reference in their entirety. Third, they are preferably compatible with existing, commonly prescribed diabetes pharmaceutical pens and other devices utilized for MDI or infusion therapy. Fourth, they transmit captured data in a common digital format compatible with smart phones or similar devices to be utilized in patient software such as a patient meaning engine. A patient meaning engine receives data, including patient blood glucose levels, calorie intake, exercise, medication doses, and other relevant data. One function of the engine is to track trends in the data and provide feedback to a user to enhance the effectiveness of patient self-care through improved understanding of the patient&#39;s disease and therapy in the patient&#39;s daily life. The meaning engine provides feedback to the patient to promote self-therapy and enables improved decision making during dosing events, e.g. prandial dosing. This feedback and the additional insight afforded by the meaning engine provide sufficient value to the patient during dosing events to influence behavioral modification. The meaning engine can also provide information or alerts to healthcare providers so that deviations from healthy trends are identified and proactively acted upon. The use of a meaning engine as defined herein promotes efficient use of physician time and eliminates or reduces poor medical treatment regimens that rely on fail-first as opposed to identifying the shortest path to a cost effective outcome. Fifth, they preferably transmit captured data to the patient meaning engine within one minute of sensing the delivered dose. Sixth, they capture data from all prescribed forms of T1 and T2 insulin and oral dose regimens. Seventh, their accuracy preferably satisfies injection standard ISO 11608. One example of utilizing the meaning engine would be titrating a new drug for a patient. Patients using a new drug, such as slow acting insulin, for the first time, by adjusting the dose each day based on analyzing insulin doses delivered and blood glucose readings over a period of time. The adjustments and data could be sent to the patient&#39;s doctor to close the loop between the doctor and patient daily while saving time for the doctor and expediting the titration process for the patient. Of course insulin is used herein as an example, and any suitable drug could similarly be titrated by monitoring relevant factors such as medicine doses and blood glucose levels or the like. 
     Embodiments of the present invention further preferably meet the following additional criteria. They can be carried with the patient and used anytime, anywhere. They preferably do not increase the number of items a diabetes patient normally carries. They are compatible with other elements in an informatics enabled outcome (IEO) system, such as Blood Glucose Monitors (BGM) and oral medicine adherence devices; that is, data transfer between devices in the system utilize a common communication platform. 
     Embodiments of the present invention are preferably easy for the patient to use; that is, the device or system functionality preferably does not require a high level of user expertise or significant training. Embodiments of the present invention improve patient safety, and preferably do not compromise patient safety in any way. 
     Exemplary embodiments of the present invention informatically enable medicament delivery devices to affirmatively capture dose delivery information. The following devices and device components typically associated with dose delivery are appropriate for informatics enablement. A vial attachment can sense movement of a syringe plunger. A pen cap can sense movement of the plunger in an insulin pen by magnetic sensing means. A magnetic sensor is preferably incorporated into a disposable insulin pen to determine plunger position. A sleeve with an integral flow sensor can be placed between an insulin pen and a pen needle. A cartridge for a reusable pen can include a sensor to determine plunger position in the cartridge. A cartridge filler can be utilized to attach a sensing element to a cartridge, A mechanism attached to the end of an insulin pen that exchanges a cannula into and from a reusable cannula hub can be provided with a flow sensor. A pen case may be provided with a magnetic position sensor to determine the position of a plunger within an insulin pen when returned to its pen case. A patch pump configured to deliver a preset number of insulin units per activation (button press) can be configured with a sensor to sense button presses. An injection patch, similar to the Insuline “Insupad” can be modified to channel the flow from different injections through a flow sensor. An injection port, similar to the device provided by Patton Medical, can also be modified in the same manner. An insulin vial or fluid reservoir can be modified to incorporate an internal floating magnet and an external sleeve with integrated magnetic sensors. Any all-in-one type device can be provided with appropriate sensors as described herein to capture dose information. As used herein, an “All-In-One” device should be understood to be a combination device, such as a device which includes for example a BGM and a method to deliver insulin dosing or a BGM and a bolus calculator. An attachment for a syringe in which at least one sensor element is connected to the syringe plunger and at least one sensor is attached to the syringe barrel. 
     A first embodiment of the invention is shown in  FIG. 1  which shows an attachment  102  for an insulin vial and a modified insulin syringe. A reusable attachment  102  engages with an insulin vial, and preferably remains attached until the insulin is exhausted. The vial attachment  102  includes at least one linear Hall-effect sensor  104  with an analog output, a flexible Printed Circuit Board Assembly (PCBA)  106 , a battery  108 , a power management system  110 , a Bluetooth Low Energy (BLE) wireless transceiver  112 , and a Real Time Clock (RTC)  114 . During the manufacturing process for the syringe  116 , an RFID chip  118  is placed into the syringe  116 , and a permanent magnet  120  is over-molded into the stopper or plunger. In an alternate embodiment a ferrous target, such as a steel disc or slug, is used rather than a magnet to further reduce the cost of the disposable significantly. 
     When a ferrous target is utilized, the Hall-effect sensor  104  is preferably back biased by integrating a magnet with the Hall sensor  104 , so that a ferrous object in range will be sensed by the Hall sensor  104 . 
     The vial attachment  102  reads the RFID chip in the syringe  116  to determine the inner diameter (ID) of the syringe barrel. The Hall-effect sensor  104  measures the linear movement of the plunger, and the dose is calculated from the ID and the plunger travel. The dose amount is time stamped and wirelessly transferred to a smart phone and/or to the “cloud” or internet. Alternately, a phone application (APP) for a Smart phone is provided in which the phone camera captures an image of the syringe just prior to injection. The syringe diameter would be recognized either by a bar code, a QR code, or the like printed on the outside of the syringe barrel, or a comparative measurement, or other optical methods that are part of a Smart phone, and the distance between the plunger and the nozzle, just prior to injection, could be determined by the same method. Similarly to the previous embodiment, these two values are then used to calculate the dose. The numerous features described herein can also be combined to provide additional embodiments, e.g. the Smart phone APP could replace the need for the RFID chip, in combination with a vial attachment that measures the movement of the plunger by sensing the position of the embedded magnet. 
       FIG. 2A  illustrates a flux density curve sensed by a Hall-effect sensor described above as a magnet passes the sensor in close proximity.  FIG. 2B  illustrates the substantially linear analog output voltage response of a Hall-effect sensor used in embodiments of the present invention. Hall-effect sensors preferably convert the linear output voltage to a digital signal for output to a processor, or the like, for further processing. 
       FIG. 3  is a cross sectional view of a syringe and vial with an informatically enabled vial attachment according to an exemplary embodiment of the invention. Depending on the total stroke intended to be sensed, multiple Hall-effect sensors may be used, but for a short stroke, only one Hall-effect sensor is needed. 
     A second embodiment of the invention is shown in  FIG. 4 . A magnetic strip  202  is over-molded into the syringe plunger. The strip  202  has numerous magnetic poles  204  that repeatedly alternate from north to south over the length of the strip. As in the first embodiment, a vial attachment would include the componentry necessary to read the RFID chip, sense the position of the plunger, and wirelessly communicate the volume of insulin injected. In this embodiment, high resolution (positional accuracy) is achieved using the same basic principle as used in an optical encoder. That is, a stacked set of magnets form a series of north and south magnetic poles that are sensed in a similar manner to black and white (or opaque and optically transmissive) optical patterns on an optical encoder. The position sensor can be a single integrated circuit that incorporates multiple Hall-effect sensors, which are arranged to detect the motion of the magnetic strip with high-resolution output that can be interfaced directly to a microcontroller. Such high resolution magnetic position sensors are available from, for example, Austria Micro Systems, ams AG. In combination with a multipole strip, a single high resolution magnetic position sensor can sense pole pairs passing the face of the sensor in order to accommodate any length stroke with a single sensor. High resolution single-chip sensors with multiple Hall-effect sensors are advantageously compact and operate for both linear and off-axis rotary motion sensing. These devices offer resolutions down to 15 microns (μm). As a reference, for a 1 ml syringe with 0.478 cm internal diameter, 56 μm displacement of the plunger would equate to 0.1 units or 0.001 ml. 
     A third embodiment of the invention is shown in  FIG. 5 , which illustrates a disposable or reusable insulin injection pen  500 . Any suitable flow sensor, including preferably Micro-Electro-Mechanical Systems (MEMS) flow sensors could be utilized to provide an informatically enabled insulin pen. One type is a MEMS micro-Coriolis mass flow meter which utilizes an oscillating tube to precisely measure the force of mass flow within the tube. A second type is a MEMS thermal time-of-flight flow sensor. In addition, a pair of MEMS capacitive pressure sensors on either side of a restriction can be used. A pen attachment  502  comprises a reusable  504  and disposable  506  portion. The reusable portion  504  is a pen cap or sleeve that attaches to the delivery end of insulin pen and is used until the insulin in the pen is exhausted. The disposable portion  506  is a plastic molded component in the shape of a small cylinder and has a MEMS flow sensor integrated into a fluidic channel through which the insulin flows. The disposable MEMS cylinder is attached to the end of the pen, and the pen needle is attached to the MEMS cylinder. A removable or retractable end cap is used to protect and expose the MEMS cylinder and allows the patient to exchange the pen needle at the time of use. The dose is preferably captured at the precise time of delivery, data is time stamped, and wirelessly transferred to a smart phone and/or the “cloud” or internet. 
     MEMS sensors typically come prepackaged by a manufacturer. Conventional MEMS sensors as described above contain not only the specific MEMS component which is necessarily very small, but also related electronics and circuitry. However, in embodiments of the present invention, the small MEMS component is preferably separated from the related circuitry. In this manner, the small MEMS component may be disposable, and the related circuitry can be reusable. In the embodiment shown in  FIG. 4 , for example, the small MEMS component would be located in the disposable flow sensor  506 , while the related circuitry would be located in the reusable pen cap  504 . This arrangement has significant cost advantages for manufacturing. As an example, a conventional MEMS sensor package may cost ˜$10, while the small MEMS component may cost less than ˜$1. Accordingly, it is advantageous to separate the small MEMS component from the related circuitry so that the expensive portion may be reused, and the less expensive portion may be disposable. Alternately a magnet is attached or incorporated into the plunger of an insulin cartridge adapted for insertion into an insulin pen. In one exemplary embodiment a Hall-effect sensor is incorporated into a pen cap, and detects the position of the plunger after injection when the pen cap is placed back on the pen. The relative movement of the cartridge plunger before and after injection corresponds to the dose amount, which is recorded, logged and preferably transmitted to a remote device such as a cloud-based storage for further processing and feedback. In another exemplary embodiment, the Hall-effect sensor and related circuitry are located in the pen case, and the relative movement of the cartridge plunger is measured each time the insulin pen is placed back into the pen case. This embodiment has the advantage of using the large amount of space available in the pen case for the Hall-effect sensor and related electronics. 
     To enable the systems described herein to capture dose delivery in real time, that is, at the time the dose is being injected into the patient&#39;s tissue, all of the system elements need to be in communication at the time of dose delivery. The pen needle captures a dose in real time when the reusable sleeve is attached to provide the following functions: (1) receive the sensed data that correlates with the volume of the dose, (2) calculate the dose, (3) time stamp the dose, (4) provide power for the sensor and these functions, and (5) to also simultaneously or at a later time wirelessly communicate the dose and time stamp elsewhere in the IEO dose capture system, such as to the patient&#39;s records in the cloud. A replacement pen cap that covets the needle end of an insulin pen and senses plunger movement does sense the movement of the plunger at the exact time of delivery. A pen cap that covers the knob end of an insulin pen and senses the knob movement and travel can preferably capture the real time delivery of the dose, because all the system elements are in communication at the time of delivery. 
     To reduce the cost of the disposable MEMS sleeve, the componentry in the sleeve, that is, the MEMS chip and electrical contacts for power and data connections to the informatics enabled pen sleeve is minimized. This device comprises a plastic sleeve into which are assembled the MEMS chip and the electrical contacts, which are either snap fit, over-molded, or clenched by a retaining component, and a septum, which would be pierced when engaged by the pen needle. These two concepts provide additional benefits as compared to the embodiments described above because they capture the time of the actual delivery as compared to the time of plunger movement to fill a syringe or the displacement in the plunger of an insulin pen sometime after the dose has been delivered, such as when the smart pen cap is placed back onto the pen. 
     The above described embodiment is also applicable to an injection port, such as the Patton Medical injection port. The embodiment for use with an injection port may be completely disposable or a combination of disposable and reusable components. Any of the MEMS sensors described above could be spliced into the fluidic pathway within an injection port and the componentry and intelligence that are provided in the informatics enabled sleeve described above would be incorporated into the injection port in the outer perimeter of the port; that is, in the area surrounding the septum into which the syringe would engage. A preferred embodiment for an injection port is a disposable/reusable design in which the disposable portion includes the adhesive, the portion of the housing to which the adhesive attaches, and the components comprising the fluidic path including the MEMS sensor and the electrical connections from the sensor to the informatics enabled reusable portion, which contains all the componentry described above in the informatics enabled sleeve. As discussed above, drug identifying techniques may also be incorporated to verify the specific drug being administered. 
     Another embodiment of the invention is illustrated in  FIG. 6 , which illustrates an informatics enabled attachment  602  for either a reusable or disposable pen  600 . This embodiment engages with the adjustment end of the pen. More specifically, a rotational turn knob  604  on the informatics enabled sleeve  602  engages with the adjustment knob (not shown) on the pen, and the sleeve portion  602  of the informatics enabled attachment slides over and engages with the outer diameter of the barrel of the pen. In one alternative of this embodiment, over-molded metallic splines located axially around the diameter of the knob are used for proximity sensing, similar to a ring counter arrangement that utilizes a proximity sensor to count gear teeth, or splines in this case, as they pass in front of the sensor. In another alternative of this embodiment shown in  FIG. 7 , a multi-pole magnetic annular ring  702  is used in combination with a Hall-effect sensor  704 . The rotational motion and direction of the cap are determined with a rotational Hall-effect sensor or an MR sensor. Determining direction requires a two sensor device such as an Allegro A  1233 , or a four sensor chip such as an ams AS5304/5306. An AMR sensor requires integration with a single Hall effect sensor to provide direction as well as 360 degree sensing. 
       FIG. 8  is an illustrative embodiment of a SMART fixed dose pen, for which the intelligence in the system is reduced, i.e. because the dose has been preset and each dose is the same, only the time of acruation/delivery needs to be captured and therefore the Hall-effect sensing arrangements described above are not required.  FIG. 9  is another illustration of either an adjustable or fixed dose pen.  FIGS. 10 and 11  illustrate embodiments of informatics enabled mechanical patch pens. As used herein, the term “patch pen” refers to a body worn device providing insulin delivery only in a fixed dose each time the user manually actuates the device, primarily utilized for prandial insulin delivery. Preferably a magnetic or metallic flag is incorporated into the mechanization or linkage within the mechanical patch pen. An informatics enabled attachment is integrated into the patch pen, in which case it is disposable, or may be in the form of a separate element that engages to the patch pen, in which case it is reusable. In one embodiment a motorized “pump engine”, that is, a fluid driver used to transfer insulin from the reservoir to the injection/infusion site, delivers 2.0 units per cycle. The motorized pump engine is described in further detail in U.S. Provisional Patent Application No. 61/976,631, filed Apr. 7, 2014, the entire contents of which are hereby incorporated by reference. This pump engine is modified to eliminate the motor and provide mechanization that enables the user to drive the pump engine by squeezing or depressing a button or buttons located on the exterior of the pump, and includes a magnetic or metallic flag located on the linkage within the patch pen, which is sensed by the informatics enabled attachment each time 2.0 units of insulin is delivered manually by the user. Any of the magnetic sensing solutions described above, optical sensing, or any suitable sensing technology, may be utilized for sensing. Additionally, the same pump engine with similar manually driven mechanization may be utilized to actuate delivery in an insulin (or other drug) pen and provides a fixed dose with each actuation, and records the amount and time of each dose. 
     Pen cases provide a clean, sealed container in which users can store their injection delivery device and consumables, such as an insulin vial, insulin pen or syringes, pen needles, lancer and lancets, and alcohol swabs. Pen cases can be either rigid, that is, having a hard exterior shell, similar in design to a jewelry box, or flexible, that is, a flexible pouch, similar to a pencil case.  FIG. 12  illustrates an informatics enabled rigid pen case  1200  according to another embodiment of the present invention. The informatics enabled pen case stores the patient&#39;s syringe or insulin pen when the device is not being used. A nest or cavity within the pen case is used to register or locate the pen, each time the user places the pen into the case. Each time the pen case is closed, the Hall-effect sensors within the pen case determine the relative position of the plunger and thereby determining the dose delivered to the patient. For a reusable pen, the insulin cartridge would need to be modified to include a magnetic or metallic flag, such as a washer shaped element with Pressure Sensitive Adhesive (PSA) on one side, that is pressed onto the exposed surface of the stopper in the cartridge, and potentially an RFID chip or some other means, such as a bar code, to convey the ID of the insulin cartridge and the type and concentration of the drug. The magnetic or metallic element is preferably incorporated into the stopper/plunger during manufacturing. In operation, each time the pen is placed into the case, sensors in the pen case scan to detect the position of the stopper and compare the current and previous positions to determine the dose delivered. Data is time stamped, stored within the case and periodically transferred to a smart phone and/or the cloud. One advantage of the pen case is the volume of space available in which to configure the informatics enabling components, which can reduce the cost and improve the performance of the solution by incorporating inexpensive, high-performance components such as off-the-shelf (OTS) batteries, rigid PCBAs, large footprint antennas, an RFID reader, a large user interface (UI) that accepts input from a touch screen, keypad, or from audible commands and provides a display with data, alerts, and warnings for the patient. To enable the use of a flexible pen case, two magnets are incorporated into the syringe or insulin pen, one fixed and the other on the moveable plunger. Each time the pen is placed into the flexible case, the line and relative distance between the two magnets is sensed allowing the dose to be calculated. This concept is also applicable to informatics enabled cartridges utilized in reusable pens and informatics enabled pens that are stored in the pen case, as described above. It will be appreciated that any suitable sensing technology may be utilized, and in particular, magneto-inductive sensing is one alternative suitable for sensing in a pen case. A magneto-inductive displacement sensor operates by using an inductive sensor coil to detect the change in magnetic field as the magnet moves. It is used in head-on sensing with a range of up to 60 mm depending on magnet size, which is used to detect the position of a magnet incorporated into the plunger piston of an insulin pen or syringe after is placed into a pen case. 
       FIG. 13  illustrates an informatics enabled pen case that is further enabled to draw the dose into the syringe. This embodiment of the pen case includes a clamping system  1301  to register the syringe, that is, to precisely locate the syringe on two axes, a nest or cradle to register the insulin vial, and a second clamping system to grip and control the movement of the syringe plunger. In operation, the user places a syringe into the nest adjacent to an insulin vial within the pen case, closes the case, and enters the dose to be delivered into the UI. The two separate clamping arrangements within the case grip the syringe. The first clamp system grips the syringe and advances the syringe to engage the syringe needle into the vial of insulin. The second moves the plunger to draw in the correct dose of insulin. The syringe is retracted from the vial either automatically or by the patient. The same arrangement may be utilized to create a positive pressure within the insulin vial. Orientation or gyroscopic sensors could be used to confirm proper orientation of the pen case for air purge or insulin draw and prompt the user to orient the pen case accordingly. An exemplary smart pen case is described in U.S. Pat. No. 7,901,383, the entire contents of which are hereby incorporated. 
     As in all embodiments described herein each injection is preferably recorded and time stamped in an electronic logbook, and transferred periodically to a peripheral monitor device such as a laptop computer, cell phone, or other user interface, for review by the patient. Alternately the data could be conveyed via a computer network to and from the cloud to the patient&#39;s health care providers. The functionality of the informatics enabled insulin pen case could be further expanded by incorporating auxiliary devices into the system, such as vital signs monitors, fitness monitors or activity trackers, and Continuous Glucose Monitors (CGMs). 
     Another embodiment takes the form of an “All-In-One” or combination device. One example of an all-in-one device available on the market is the Dario, by LabStyle Innovations. The Dario integrates a glucose meter, lancet, strip dispenser, and phone application for either IOS or Android into a compact device. Like the pen case embodiment described above, an all-in-one device has sufficient size and volume to incorporate informatics enabling componentry described above to allow an informatically enabled insulin pen or syringe to be attached, that is, by providing a nest or holster for the pen or syringe to be physically and electrically engaged to the all-in-one housing. In this case, the connection provides retention of the pen or syringe and transfer of data. Such a device is described, for example, in U.S. Published Application No. 2011-0054390, the entire contents of which are hereby incorporated by reference. Alternatively, a wireless communication solution such as low energy Bluetooth (BLE) or Near Field Communication (NFC) could be utilized to communicate directly to a Smart phone. An example of a smart phone device communicating with other on body devices in a personal area network is described in U.S. Published Application No. 2011-0022025, the entire contents of which are hereby incorporated by reference. 
     Another embodiment is an informatics enabled insulin cartridge that is used in conjunction with an informatics enabled reusable pen. The insulin cartridge is modified to include a magnetic or metallic flag, such as a washer shaped element with Pressure Sensitive Adhesive (PSA) on one side, that is pressed onto the exposed surface of the stopper in the cartridge, and an RFID chip or some other means, such as a bar code, to convey the ID of the insulin cartridge, and the specific drug type and concentration. The cartridge would work in conjunction with an informatics enabled attachment for a reusable pen. Alternately, the magnetic field strength could be used to distinguish between different cartridges, eliminating the need for an RFID chip on the disposable device and an RFID reader within the informatics system. The cartridge is preferably modified during the manufacturing process, following the filling process, or by the patient, either manually or automatically as part of a cartridge filling process designed for home use. 
       FIG. 14  illustrates an informatically enabled syringe sleeve according to an exemplary embodiment of the invention. The syringe sleeve  1400  includes a plurality of magnetic position sensors  1402 . The syringe  1404  has an embedded RFID chip  1406  and a magnet  1408  that is sensed by the Hall-effect sensors  1402  to determine a dose amount. Of course, as will be appreciated by one of ordinary skill in the art, any suitable type of MEMS sensing such as those discussed herein may be used in place of magnetic position sensing. 
     In another embodiment, external electrodes are attached to the insulin reservoir and a variable capacitance value is sensed based on the fluid level of the reservoir. Electrodes are preferably printed onto any insulin reservoir during manufacturing, and may also be manufactured as a strip that is attached to an insulin reservoir. Alternatively, as shown in  FIG. 15 , an informatics enabled sleeve  1500  is provided with the electrodes  1502  provided on the inside diameter and which would contact the reservoir when attached to the pen, syringe, vial or patch pump. The electrode  1502  may be printed onto the sleeve or manufactured in any other suitable manner. The electrode  1502  preferably spans a dimension that corresponds to the volume of insulin in the vial. In this embodiment, the sleeve  1500  and strip  1502  are advantageously re-usable. In another embodiment of the informatically enabled insulin vial, the electrodes of a capacitance sensor are incorporated into the vial attachment, such that when the vial attachment is engaged with the vial, the electrode strip is in intimate axial contact with the vial. 
       FIG. 16  illustrates an informatically enabled vial sleeve  1600  according to an exemplary embodiment of the present invention. As illustrated, a floating magnetic ring  1602  is provided inside a medicine vial  1604 . The ring magnet outer diameter is slightly smaller than the inner diameter of the vial so that the ring freely moves within the vial according to the fluid level within the vial. The ring magnet  1602  is preferably placed into a drug vial prior to sealing the vessel. A typical insulin vial may also be modified to accommodate a rigid magnetic ring, or a flexible magnetic ring may be wrapped in a coil, inserted into a vial through a standard vial neck, allowing the coil to unwind after insertion to a diameter that is smaller diameter than inner diameter of the vial. In the case of an insulin vial, the ring magnet is preferably coated with an insulin compatible material, such as a polymer, which is compatible with insulin and of sufficient thickness and overall buoyancy to enable the ring to float. As illustrated, the level of the ring is sensed by a linear magnetic position sensor, such as a Hall-effect sensor. 
       FIG. 17  illustrates another informatically enabled vial sleeve  1700  according to an exemplary embodiment of the invention. In this embodiment, floating magnetic beads  1702  are utilized to sense the level of fluid in a drug vial, such as an insulin vial  1704 . A smart vial sleeve  1700  is provided an attached to the medicine vial  1704 . The vial sleeve  1700  senses the layer of magnetic beads floating on the surface of the insulin. The beads are of sufficient diameter that they are unable to be drawn into a dose. That is, the beads  1702  are larger in diameter than the needle or cannula or a syringe used to draw insulin from the vial. Advantageously, a user can add the magnetic beads  1702  to any medicine vial post-manufacture, to enable the smart vial sleeve  1700 . In one embodiment, the magnetic beads are added to an insulin vial during the filling process in manufacturing. In another embodiment, the filled insulin vial is shipped together with a syringe filled with magnetic beads, the syringe preferably having a large cannula to inject beads into vial. The cannula of the syringe or other device used to draw insulin from the syringe is smaller than the beads to prevent beads being drawn into the injection device. The number of magnetic beads used is preferably sufficient to substantially cover the majority of the surface of the liquid medicine inside the vial. The vial sleeve attachment utilizes a linear magnetic position sensor, such as a fall-effect sensor, MR or AMR sensor to detect the level of fluid remaining in the vial according to the position of the floating magnetic beads within the vial. 
       FIGS. 18A and 18B  illustrate a linear magnetic positioning arrangement  1800  attached externally to a syringe  1802  according to an exemplary embodiment of the present invention. The syringe attachment  1800  conveniently attaches to a syringe  1802 , so that a standard syringe may be utilized without modification. A first attachment comprises at least one magnet  1804  that attaches to the syringe  1802 , and a second attachment comprises a linear magnetic position sensor  1806 , such as a Hall-effect sensor, an MR sensor or an AMR sensor, to detect the position of the magnet(s)  1804 . The first attachment  1804  connects to the syringe plunger and the second attachment  1806  connects to the syringe barrel, such that the movement of the plunger is tracked to determine the dose delivered. The smart syringe attachment  1800  preferably recognizes the “home” position of the plunger, that is, the position where the plunger is fully advanced and no fluid delivery is possible. In practice, the syringe plunger may be retracted and advanced many times during a single dose delivery cycle. To identify the movement associated with the dose delivery from other plunger movements, such as the movements used to inject air into the vial, the smart attachment  1800  analyzes the complete cycle of plunger movements each time a syringe is used, and identifies the dose delivered from the final movements, when the plunger advances to the home position for the final time, and from other sensed elements in the dose delivery cycle. 
       FIG. 19A  illustrates a smart injection port  1900  according to an exemplary embodiment of the present invention. The exemplary smart injection port preferably comprises a lower housing  1902  and an upper housing  1904 . The lower housing includes an adhesive surface  1906  to facilitate attachment of the smart injection port to a patient&#39;s skin  1908 . A septum  1910  is arranged between the upper and lower housings  1902 ,  1904 . The septum  1910  provides access to a cannula  1912  that is inserted into a patient&#39;s skin  1908 . The septum  1910  may be pierced by an injection syringe, or the like, to inject insulin into the patient through the cannula  1912  without requiring a needle stick for each injection. The smart injection port  1900  includes a MEMS flow sensor  1914  arranged in the flow path between the septum  1910  and the cannula  1912 . MEMS flow sensor  1914  is electrically connected to related electronics located in area  1916  of the injection port  1900 . The related electronics include a power supply, processor, and wireless transceiver for transmitting flow measurements to a remote device. Housing  1902  is preferably disposable, and includes the MEMS flow sensor  1914 . Housing  1904  is preferably reusable, and includes the related electronics in area  1916 . The MEMS flow sensor is preferably a thermal time of flight sensor, but any suitable MEMS flow sensor could be employed. 
       FIG. 19B  illustrates a conventional single-package MEMS flow sensor  1920 . In the single package MEMS flow sensor, the actual MEMS printed sensor  1922  is combined with related electronics  1924 . The MEMS printed sensor  1922  includes at least one heater, at least one sensor and a flow channel through which a fluid such as insulin flows. The related electronics  1924  are electrically connected to the MEMS printer sensor  1922  within the single package, and include an integrated circuit, processor, power supply, wireless transceiver chip, and the like. 
       FIGS. 19C and 19D  illustrate an improved MEMS flow sensor  1930  that includes only relatively low cost disposable parts that should be replaced with each use due to contact with insulin or the like. As illustrated in  FIG. 19C , the MEMS flow sensor  1930  includes an input side  1932  with an input flow tube  1934  through which liquid such as insulin flows to the MEMS printed sensor element  1936  (shown in  FIG. 19D ). The MEMS flow sensor  1930  further includes an output side  1938  with an output flow tube  1940  through which liquid such as insulin flows from the MEMS printed sensor element  1936  to downstream elements. As shown in  FIG. 191 ), the MEMS flow sensor  1930  includes electrical contacts  1942  for connecting the MEMS printed sensor element  1936  to related electronics, as described above. The related electronics include, for example, an integrated circuit, a processor, a power supply, and a wireless transceiver chip. Because the related electronics are separately packaged, they may be incorporated into a reusable element in an exemplary medication delivery device, thus significantly reducing overall cost. 
       FIG. 20  illustrates a system according to an exemplary embodiment of the present invention. The system  2000  includes various components for capturing data and at least one calculating element for receiving data and performing calculations on the data. As illustrated the exemplary system preferably includes a carbohydrate input element  2002 , an oral medication input element  2004 , and blood glucose monitor (BGM)  2006  and/or a continuous glucose sensor (CGM)  2008 . The system preferably includes a wellness data input element  2010 . Finally the system preferably includes one of the various embodiments of dose capture device  2016  as described herein. As an example, a smart pen  2016  is illustrated. Together these devices input the significant relevant data needed to monitor a patient with a disease such as diabetes for improved diabetes management. An exemplary carbohydrate input device  2002  can be an app running on a user&#39;s cellphone  2011 , or the like, which lets the patient input food and drink consumed. Similarly, the same or a related app can serve as an oral medication input element  2004  and permit the user to track oral medications ingested. In addition, the oral medication input element  2004  can be automated to alert the user to take medication, and to confirm and automatically transmit data related to the oral medication taken to the secure hub  2012 . The BGM  2006  and/or CGM  2008  preferably communicate blood glucose readings directly to a data hub device  2012 . Wellness data can be input by a separate device  2010  or by a related or the same app as described above. The dose delivery information device  2016  according to exemplary embodiments described herein, preferably delivers dose information, such as insulin injected into the patient, in real or near real time. All of the data is received locally by a smart device, such as a cellphone  2011  running the app or apps discussed above. It should be appreciated that while the carbohydrate input element  2002 , the oral medication input element  2004 , the wellness data input element  2010 , the cellphone  2011 , and the data hub  2012  are shown as separate elements, all or any combination of them may be combined into a single cellphone or similar computing device. Data is analyzed and calculations are performed locally by the smart device and/or smart phone  2011 , and the data hub  2012  is used to transmit data securely, that is, encrypted, to a remote server such as a cloud storage server, and in turn to perform calculations on all of the data received, provide feedback to the user, send all or a portion of the data to a remote health management access point  2020 , such as cloud storage, where the information can be accessed by healthcare stakeholders, such as the patient&#39;s physician, caregiver, pharmacy, and family. Conversely, alerts, reminders, and interventions can be provided by the user&#39;s network, e.g. an HCP, securely through the data hub  2012 . 
     An embodiment of the present invention includes several features. The first is dose capture, which measures the volume of insulin delivered and a time stamp. This information is preferably captured in a manner that is transparent to the patient. The second is data transfer, which occurs at different interfaces, such as between the dose capture device and the user interface. (UI), or between the patient and health care provider. Additional functions include data transfer to the patient, health care provider, such as a PCP, endocrinologist, or nurse educator, or another risk bearing entity, such as a family member, or diabetes support network. BGM data/CGM data may be incorporated, measured and time stamped. Life style data such as diet and exercise may be captured and considered, Embodiments of the present invention preferably are compatible with fitness monitors and nutrition Apps. Embodiments of the invention preferably include additional intelligence to provide helpful alerts, warnings, recommendations, interventions, intelligent decision making, such as trend analysis, predictions, and therapeutic modifications. Finally, embodiments of the present invention may incorporate or consider oral medication. Preferably, embodiments of the invention are compatible with an oral medication adherence device, such as a Smart pill container. 
     Although recent advances in infusion pump therapy have reduced the growth rate of the multiple daily injection (MDI) segment, the overwhelming majority of diabetic patients on insulin therapy continue to receive delivery through MDis, and primarily with disposable insulin pens. 
     The cost of incorporating the necessary components to informatically enable a disposable syringe or insulin pen could be reduced where the informatically enabled portion of the device could be reused, such as in a replacement cap on an insulin pen, or the number of uses of the disposable device could be increased such that the added cost per use would be acceptable, such as a exchanging needle cannulae into a “universal” needle hub. Such a hub is described, for example in U.S. Published Application No. 2012/0041417, the entire contents of which are hereby incorporated by reference. The increase in size of the device is another consideration. Adding an appendage to an insulin pen or modifying the pen cap and creating a larger, less appealing envelope, such that the modified device needs to be carried in a purse or pack is undesirable. Another issue is creating a universal solution that can be utilized with most currently marketed insulin pens. 
     A preferred embodiment that satisfies the above criteria is an informatics enabled insulin pen case, which could utilize a number of different methods to capture the delivered dose, such as taking the weight of the insulin pen each time the pen is placed in the case and the case is closed. The case provides sufficient space to incorporate the necessary electronics, and by having potentially more space than needed, the design can be tailored to utilize inexpensive electronics, such as a rigid PCBA, a disposable battery that has been commoditized, large footprint antenna options for low power data transmission, and ease of assembly. 
     In addition to dose capture, informatically enabled medication delivery devices can perform additional functions. For example, an informatically enabled insulin pen with a smart cap can identify particular pen needles for use with the insulin pen. Further, the informatically enabled insulin pen can advantageously reduce or prevent unintended uses.  FIG. 21  illustrates a first exemplary system  2100  including an insulin pen  2102 , a smart pen cap  2104 , a package of disposable pen needles  2106 , and a smart phone  2108  running an application. Using the smartphone&#39;s camera, the pen needle package barcode  2112  (or any suitable identification) is read by the cellphone. The cellphone  2108  in turn communicates with a cloud-based database  2110  to verify the pen needle package by manufacturer, unit size, lot number, and other factors identified by the barcode. The cellphone  2108  could confirm the barcode validity in real time or near real time, or alternately, could periodically poll the could-based database and download a complete list of valid barcodes and associated information such that communication with the cloud-based storage is not necessary at the time the barcode is scanned. In this embodiment, the barcode  2112  is static and printed on all pen needle packages, and so is subject to reuse. 
     In another embodiment illustrated in  FIG. 22 , the system  2200  includes pen needle packages  2106  that are imprinted with unique barcodes  2202  (or any suitable unique identifier). The cellphone  2108  is used to scan the unique identifier  2202  and communicates with a cloud-based database  2110  to confirm that the unique identifier  2202  is in fact unique and remains valid. Such a system could advantageously be used to assist recalls as needed, and to prevent the use of unauthorized pen needles. In either of the exemplary systems described above, a down counter is preferably set to the number of disposable pen needles in the identified package, and certain functions are restricted after the counter reaches zero, indicating that the package should be exhausted. For example, the smart cap would stop logging delivered doses once the needle package is exhausted, and until a new package is authorized. 
     In another exemplary system  2300 , a smart sleeve  2302  is provided in each package of disposable pen needles  2106 . The smart sleeve  2302  is connected to the pen needle, and the smart sleeve contains an RFID chip. The RFID chip may be read by either the smart cap  2104 , or the cellphone  2108 , to verify the pen needle package. Advantageously, the smart sleeve  2302  is read by the smart cap  2104  each time the cap is placed on the insulin pen  2102 . If the smart cap  2104  reads the RFID chip, the chip information is preferably transmitted to the smartphone  2108 , which in turn communicates with a cloud-based database  2110  as discussed in the above described examples. RFID chips preferably include lot information, manufacturing date, and any other suitable information, and do not require printing space on the pen needle package. Similar to the example provided above, a down counter is preferably provided to restrict higher level functions once the disposable pen needles provided in the package  2106  should be exhausted. The smart sleeve  2302  preferably forms an interface between the insulin pen  2102  and pen needles using the existing threaded interfaces on the pen and pen needles. That is, the sleeve includes inward facing threads to mate with the insulin pen  2104 , and outwardly facing threads to mate with the disposable pen needles. In one version the smart sleeve includes a septum and a cannula, and forms part of the flow channel between the insulin cartridge and the pen needle. In this version, the smart sleeve preferably includes a flow sensor such as a MEMS flow sensor discussed above. In another version, the pen sleeve merely contains identifying information, such as an RFID chip to identify the lot number, number of units, and other information of the disposable pen needle package. In this version the smart sleeve still includes inwardly facing and outwardly facing threads for mating with the pen and pen needles, respectively, but the sleeves forms a hollow cylinder and although the pen needles mate with the smart sleeve, the inwardly facing cannula of each pen needle still pierces the septum of the insulin pen, such that the smart sleeve does not form part of the fluid path between the insulin cartridge and the pen needle. 
     In another exemplary system  2400 , a smart cap  2104  is provided with a bank of emitters  2402  and a bank of sensors  2404 . A portion of the emitters  2402  and sensors  2404  sense the location of the plunger in the pen needle before and after an injection to verify the dose delivered to the user. At least one other emitter and sensor are located adjacent to the pen needle  2406  such that when the smart cap  2104  is attached to the pen  2102  the smart cap can identify the pen needle based on a signal received by the sensor. The smart cap  2104  communicates with the cellphone  2108 , and the cellphone  2108  communicates with a cloud-based storage  2110  as discussed above. In this embodiment, proprietary disposable pen needles are advantageously marked such that the emitter and sensor recognize a unique signal identifying the pen needle as authentic. The signal may be optical, magnetic, or any other suitable signaling means. 
     In yet another exemplary system, all of the features above are combined. That is, the disposable pen needle package  2106  is imprinted with a unique barcode  2202  (or any suitable marking), the package of pen needles  2106  is provided with a smart sleeve  2302 , and the disposable pen needles are manufactured with a unique signature, such as an optical, magnetic, or any other suitable signature signal. The smart cap  2104  triggers a down counter in the smart sleeve  2302  or the smartphone  2108 , and senses the unique signature of authentic pen needles. If the pen needle is not recognized some or all functions may be restricted as discussed above. A down counter is used to restrict higher level features once the package of pen needles should be exhausted. 
     Although only a few embodiments of the present invention have been described, the present invention is not limited to the described embodiment. Instead, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the invention.