INTRODUCTION

[001] The present disclosure is related generally to a metal detector and metal detection techniques for detecting metal contaminants in dose forms comprising ingestible

components. More particularly, the present disclosure is related to a metal detector and metal detection techniques for detecting metal contaminants in dose forms comprising ingestible components during the manufacturing process.

[002] Broadly speaking, a dose form is a measured quantity of an ingestible substance. An ingestible component is a device that is intended to be ingested by a living subject. In one aspect, the ingestible component is a sensor. A sensor-enabled dose form is a sensor combined with the dose form. Sensors may take many forms.

[003] In one example, the sensor may be an ingestible event marker (lEM), a radio frequency identification (RFID) device, a coil, and the like. A sensor may be an event indicator system configured to emit a detectable signal upon contact with a target internal physiological site. One such event indicator system includes systems configured for conductive communications, e.g., an lEM, as hereinafter described. In another aspect, the event indicator system may include systems configured for inductive communications, e.g., an RFID device. In various aspects, other modes of communication, as well as

combinations of modes of communication, are possible.

[004] While configurations may vary, in one example a sensor-enabled dose form comprises a sensor stably associated with a carrier, such as a tablet or capsule. In the particular example where the sensor is embodied as an lEM, the lEM may include an integrated circuit component and two dissimilar materials, e.g., two electrodes. Further components may include, for example, a current path extender and/or various other components which may, in certain instances, may be associated with a framework. When the lEM (sometimes referred to herein in certain aspects as an "ingestible event marker identifier" or "identifier"), contacts fluid at an internal target site, such as stomach fluid, a power source is completed that provides power to the integrated circuit component to provide a communication.

[005] Sensors, such as, for example, an I EM, may be employed in a variety of different applications. One application of interest is monitoring how a patient adheres to a prescribed pharmaceutical therapeutic regimen. In these applications, lEMs are combined with the pharmaceutical dosages of the therapeutic regimen, where the carrier component of the marker may include an active pharmaceutical ingredient of interest or be a placebo, as desired. By monitoring for communications, e.g., a current path associated with the ingestible event marker, accurate information regarding patient adherence with a prescribed pharmaceutical therapeutic regimen may be obtained. Patient adherence data obtained with ingestible event markers holds great promise, both with patients who have been prescribed approved pharmaceuticals and with patients who are participating in clinical trials.

[006] Sensors, such as, for example, an I EM, also may be employed in protocols that do not involve administration of a pharmaceutically active agent. For example, ingestible event markers may be used to monitor an occurrence of interest, such as a mealtime, a symptom, etc. As such, applications in which ingestible event markers may find use include dieting, monitoring patients for physiological symptoms of interest, and the like.

[007] A sensor may contain metal elements that are germane to their operation. Such necessary metal elements differ based on the type of sensor. For example, a sensor may contain an IC and/or two or more dissimilar metals (e.g., IEM), coils, patterned antennas (e.g., RFID device), and the like. Conventional manufacturing processes that include a metal detection process for screening out dose forms with metal contaminants as part of a risk mitigation strategy will be challenged when a sensor-enabled dose form is inserted in the manufacturing process. Since sensor-enabled dose forms may contain metal elements that are necessary to their normal operation, conventional metal detection screening equipment cannot discriminate between wanted and unwanted metal elements located in a sensor-enabled dose form. In a quality control inspection context, for example, metal detection techniques for use on a production line as a process control check must be able to detect metal contaminants above the detection signal caused by the sensor in order to ensure practical usefulness of the metal detection process. Despite advances in

conventional metal detection techniques and apparatuses, the present disclosure provides novel metal detection techniques and apparatuses that are capable of detecting metal contaminants in a sensor-enabled dose form above a metal detection threshold of an ingestible sensor alone. SUMMARY

[008] In one aspect, a method comprises orienting a sensor-enabled dose form in a predetermined orientation; receiving the sensor-enabled dose form through an aperture of a metal detector; generating a detection signal by the metal detector in response to receiving the sensor-enabled dose form through the aperture of the metal detector; comparing the detection signal to a predetermined threshold; and determining the presence of a metal contaminant in the sensor-enabled dose form based on the comparison of the detection signal and the predetermined threshold.

[009] In addition to the foregoing, various other method and/or system and/or program product aspects are set forth and described in the teachings such as text (e.g., claims and/or detailed description) and/or drawings of the present disclosure.

[010] The foregoing is a summary and thus may contain simplifications, generalizations, inclusions, and/or omissions of detail; consequently, those skilled in the art will appreciate that the summary is illustrative only and is NOT intended to be in any way limiting. Other aspects, features, and advantages of the devices and/or processes and/or other subject matter described herein will become apparent in the teachings set forth herein.

[011] In one or more various aspects, related systems include but are not limited to circuitry and/or programming for effecting herein-referenced method aspects; the circuitry and/or programming can be virtually any combination of hardware, software, and/or firmware configured to effect the herein-referenced method aspects depending upon the design choices of the system designer. In addition to the foregoing, various other method and/or system aspects are set forth and described in the teachings such as text (e.g., claims and/or detailed description) and/or drawings of the present disclosure.

[012] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. FIGURES

[013] The novel features of the embodiments described herein are set forth with particularity in the appended claims. The embodiments, however, both as to organization and methods of operation may be better understood by reference to the following description, taken in conjunction with the accompanying drawings as follows.

[014] FIG. 1 is a componential cutaway/transparent view of one aspect of a metal detector.

[015] FIG. 2 is a schematic diagram of one aspect of the configuration of coils of the metal detector shown in FIG. 1.

[016] FIG. 3 is a depiction of a typical voltage signal appearing between output terminals of the metal detector shown in FIG. 1 .

[017] FIG. 4 shows a typical sensitivity plot of the field generated within an aperture of the metal detector shown in FIG. 1 .

[018] FIG. 5 is a graphical representation of dose forms (e.g., compressed tablets) containing an event indicator system passed through the aperture of the metal detector shown in FIG. 1 without orientation or positional control.

[019] FIG. 6 shows an end view of a guide for passing a dose form through an aperture of the metal detector shown in FIG. 1 .

[020] FIG. 7 shows a side view of the guide shown in FIG. 6.

[021] FIG. 8 illustrates a dose form containing an event indicator system located within a guide in a horizontal orientation.

[022] FIG. 9 illustrates a dose form containing an event indicator system located within a guide in a vertical orientation.

[023] FIG. 10 shows the guide shown in FIGS. 6 and 7 located inside the center of the metal detector aperture shown in FIG. 1 .

[024] FIG. 1 1 A is a graphical representation of overall orientation effects dominated the signal strength, with horizontally oriented event indicator systems (X's) showing up ~100x stronger than vertically oriented event indicator systems (O's).

[025] FIG. 1 1 B is a zoomed in graphical representation to make the smaller signals from the vertical orientation more easily visible. [026] FIG. 12 is a graphical representation showing that position within the aperture did not affect detected signal strength of the spherical standards included with the metal detector.

[027] FIG. 13 is a graphical representation of a comparison of minimum signals generated by sensor-enabled dose forms with minimum signals generated by standards.

[028] FIG. 14 is a graphical representation of amplitudes of dose forms (e.g., compressed tablets) containing an event indicator system (X's) and empty skirts (O) implanted with metal contaminants of known size directly compressed in the tablet.

[029] FIG. 15 is one aspect of a metal detector system.

[030] FIG. 16 is another aspect of a metal detector system.

[031] FIG. 17 is a block diagram representation of one aspect of the event indicator system with dissimilar metals positioned on opposite ends.

[032] FIG. 18 is a block diagram representation of another aspect of the event indicator system with dissimilar metals positioned on the same end and separated by a nonconducting material.

[033] FIG. 19 shows ionic transfer or the current path through a conducting fluid when the event indicator system of FIG. 17 is in contact with conducting liquid and in an active state.

[034] FIG. 19A is an exploded view of the surface of dissimilar materials of FIG. 19.

[035] FIG. 20 provides views of various ingestible event marker configurations.

DESCRIPTION

[036] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols and reference characters typically identify similar components throughout the several views, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here.

[037] Before explaining the various embodiments of the metal detector apparatus, system, and method in detail, it should be noted that the various embodiments disclosed herein are not limited in their application or use to the details of construction and arrangement of components illustrated in the accompanying drawings and description. Rather, the disclosed embodiments may be positioned or incorporated in other embodiments, variations and modifications thereof, and may be practiced or carried out in various ways. Accordingly, embodiments of the metal detector apparatus, system, and method disclosed herein are illustrative in nature and are not meant to limit the scope or application thereof.

Furthermore, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the embodiments for the convenience of the reader and are not to limit the scope thereof. In addition, it should be understood that any one or more of the disclosed embodiments, expressions of embodiments, and/or examples thereof, can be combined with any one or more of the other disclosed embodiments, expressions of embodiments, and/or examples thereof, without limitation.

[038] Also, in the following description, it is to be understood that terms such as front, back, inside, outside, top, bottom and the like are words of convenience and are not to be construed as limiting terms. Terminology used herein is not meant to be limiting insofar as devices described herein, or portions thereof, may be attached or utilized in other orientations. The various embodiments will be described in more detail with reference to the drawings.

[039] In one aspect, the present disclosure is directed generally to a method for detecting metal debris in sensor-enabled dose form. A dose form is a measured quantity of an ingestible substance, and in one aspect, the substance may be a pharmaceutical. Thus, the dose form may be in the form of a tablet or capsule, although other form factors are envisioned. An ingestible component is a device that is intended to be ingested by a living subject. In one aspect, the ingestible component is a sensor. A sensor-enabled dose form is a sensor that is combined with a dose form. It will be appreciated that the sensor may be located on the surface of or embedded within the dose form. Throughout this description, for convenience and clarity of disclosure, the expression sensor-enabled dose form is used to refer to any combinatioOn of dose form and sensor, regardless of whether the sensor is located on the dose form or embedded within the dose form, without limitation.

[040] Sensors may take many forms also. In one aspect, a sensor may contain conductive metal material that is germane to the operation of the sensor. Such conductive metal does not, however, interfere with the metal detection apparatus and method. Accordingly, metal debris in a sensor-enabled dose form may be detected by the metal detection instrument in the presence of the sensor. In one aspect, the sensor is oriented during passage through a coil of a metal detection instrument. The orientation of the sensor as it passes through the coil modifies the response of the detection signal obtained from the metal detection instrument. Accordingly, the detection signal may be exploited to characterize either the sensor or metallic debris, or combinations thereof. Such signal characterization may be employed in several ways. .

[041] For instance, in one method, the characterized detection signal may be employed to positively identify the presence of a sensor in a sensor-enabled dose form and, in another method, the characterized signal may be employed to detect metal debris present in or on a sensor-enabled dose form. In other words, the detection signal generated by the metal detector may include a first component associated with the sensor and a second component associated with metal debris, if any, that may be present in or on the dose form or sensor. Thus, modifications of the detection signal generated by the metal detector enable the sensor signal component to be separated from the metal debris signal component. This approach enables the detection of metal debris at the same or a similar sensitivity regardless of whether a sensor is present in the dose form.

[042] To increase the inspection throughput, the sensor-enabled dose forms may be assisted through the metal detection coil using any suitable technique including gravity, air pressure, conveyors, and the like.. Automated evaluation of the detection signal for sensor detection and/or debris detection may be integrated into an instrument or may be done separately. An adjustable threshold or trigger level may be employed to set detection sensitivity, and separation of sensors, metal debris, and/or dose forms, by signal level may be automated at the instrument or separately.

[043] In one aspect, the present disclosure provides a metal detector and metal detection techniques for detecting sensor-enabled dose forms during the manufacturing process as a way to control or screen sensor-enabled dose forms. Specifically, the disclosed metal detector and metal detection techniques are capable of resolving a detection signal produced by the metal detector to discern the sensor signal component (e.g., an IEM) from the metal debris signal component as the sensor-enabled dose form passes through a coil of the metal detector.

[044] In order to evaluate the efficacy of the novel metal detector and techniques associated therewith certain measurements were made as presented hereinbelow. The measurements were carried out on a modified CEIA THS/PH21 N metal detector unit. It will be appreciated that such measurements are reasonably indicative of the effectiveness of the novel metal detector and techniques, but should not be taken as absolute or construed to in a limiting manner. Findings may not be applicable to other metal detectors or configurations.

[045] The detection signal produced by the metal detector as the sensor-enabled dose form passes through an aperture of the detector is both position and orientation dependent. In one aspect, this dependency can be minimized by passing the sensor-enabled dose form vertically through the center of the detector aperture.

[046] The detection signal may be characterized by using samples of compressed tablets fabricated with metal spheres of know diameters. The metal spheres can be located in samples with and without sensors (e.g., no IC die). A first set of samples without sensors containing only metal spheres of ferrous metal (0.3mm and 0.5mm), non-ferrous metal (0.3mm and 0.5mm), and stainless steel (0.5mm) were passed through the metal detector and a first detection signal was obtained. Afterwards, a second set of samples containing sensors plus the same metal spheres as the first samples were vertically oriented in the center of the metal detector aperture and passed through the metal detector. A second detection signal was obtained. Thus, a first threshold can be set in the metal detector to detect metal debris in dose forms without sensors and a second threshold can be set in the metal detector to detect metal debris in dose forms with sensors. Baseline detection signals produced by a sensor alone also may be established. Other combinations and variations of thresholds may be obtained.

[047] As described in detail hereinbelow, dose forms intentionally contaminated with metal spheres of known diameter and composition were detectable both with and without a sensor being present in the dose form, as long as the dose forms were passed individually through the detector and passed in a configuration that minimizes the background signal from the metal portions of the sensor (e.g., the IC). In one aspect, the sensor, and therefore the IC, may be oriented vertically in the center of the detection aperture and in another aspect, the sensor, and therefore the IC, may be oriented horizontally. Additional orientations between the vertical and horizontal would likely yield suitable results as are not excluded from the scope of the present disclosure.

[048] In one aspect, multiple metal detectors can be employed in series. For example, two metal detectors (e.g., scanners) in series can be used to verify the presence of a sensor within a dose form by first passing it through the metal detector in a horizontal (or vertical) orientation followed by passing the sensor-enabled dose form in a vertical (or horizontal) orientation to verify that the detection signal is not the result of metal contamination.

[049] TABLE 1 summarizes lot numbers for compressed tablets containing a sensor in the form of an event indicator system (e.g., IEM) used in metal detector testing. The tests were conducted with a CEIA THS/PH21 N metal detector, MD scope software 4.50.28, CEIA metal detector standards encased in plastic pucks, 0.22mm FE, 0.28mm NF, 0.37mm SS the compressed tablets containing an event indicator system orientation guide (FX006322) Spherical metal test standards used to establish minimum detection limits of metal detectors (BBs), ferric materials (FE), non-ferric materials (NF), stainless steel (SS) at both 0.3mm and 0.5mm the compressed tablets containing an event indicator system lots are given it TABLE 1. In TABLE 1 , "MIT tool" refers to the specific tool used to compress the tablets containing IEMS, "IEM type" refers to an IEM type event indicator system, specifically whether it contains an IC (standard IEM) or not (skirt only), "BB type" refers to the metal defect standard size and material, and "DF lot" refers to a tracking number for the samples.

[050] TABLE 1

[051] Prior to turning to a discussion of specific test configurations and results obtained therewith to confirm the efficacy of the metal detection apparatus, system, and method according to the present disclosure, the description now turns briefly to FIGS. 1 -4 for a discussion of a metal detection system and configuration.

[052] Accordingly, turning now to FIG. 1 , a componential cutaway/transparent view of a conventional metal detector 100 is shown. The metal detector 100 comprises a body 102 defining an aperture 106 to receive a sample such as a sensor, a sensor-enabled dose form or simply a dose form, therethrough. Although the depicted detector 100 comprises three coils 104a, 104b, 104c embedded on the body 102, a single coil, double coil, or other suitable number of coils greater than three may be employed, without limitation.

[053] FIG. 2 is a schematic diagram of one aspect of the configuration of the coils 104a-c of the metal detector 100. As shown in FIGS. 1 and 2, in one aspect, the detector 100 is implemented as a balanced coil system where the center coil 104b is coupled to input terminals 200 and generates a field, wherein a field could be an electric field, electrostatic field, magnetic field, among other fields, and hence, the center coil 104b is referred to as a transmitter coil. The outer coils 104a and 104c act as receiver coils and detect

perturbations in the field generated by the transmitter coil 104a caused by a metal object passing through the aperture 106 in the direction indicated by arrow labeled "Product Flow". Any perturbation of the field results in a voltage difference between the receiver coils 104a, 104c at output terminals 202. A typical voltage signal 300 appearing between output terminals 202 as material passes down the aperture 106 is depicted in FIG. 3, for example. One example of a conventional metal detector 1 10 such as shown in FIGS. 1 -3 is produced by Mettler-Toledo, LLC of Tampa, FL.

[054] Any suitable metal detector may be employed and the disclosure is not limited in scope to the particular metal detector 100 shown in FIGS. 1 and 2. For example, any metal detector which responds to metal in proximity to a sensor coil may be readily employed. The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating field. If a piece of electrically conductive metal is located proximate to the coil, eddy currents will be induced in the metal, and this produces a field of its own. Thus, in one aspect, a one coil system may be employed as a metal detector. In another aspect, a second coil may be added to the single coil system where the second coil can be used to measure the field (acting as a magnetometer). Thus, the change in field due to the metallic object can be detected.

Alternatively, in a two coil system, a first coil is the transmitting coil and the second coil is the receiving coil. Metal detection configurations that employ three or more coils also are contemplated to be within the scope of the present disclosure. Accordingly, the disclosed embodiments are not limited in this context.

[055] The transmitter coil 104b is coupled to a field generator by way of the input terminal 200 to excite the coil 104b with a field that can be influenced by a metal object located in proximity thereto. The receiver coils 104a, 104c are coupled to a comparator circuit to detect the signal at the output terminals 202 and condition and/or amplify the signal such that it can be compared to a predetermined threshold. The threshold is selected such that the circuit can detect a contaminant metal object in the presence of a sensor-enabled dose form, which itself comprises a sensor having, for example, a minimum amount of metal in the form of an IC and/or dissimilar metals deposited on the IC. In one aspect, a controller comprising a processor can be employed to determine when to trigger the presence of a contaminant. The comparator circuit is configured to compare the amplitude of the detected signal to a predetermined threshold and output a control signal. A controller coupled to the apparatus receives the control signal from the comparator circuit and determines whether a metal contaminant is present in the sensor-enabled dose form based on the control signal. If a metal contaminant is detected, the controller is configured to reject the contaminated sensor-enabled dose form.

[056] The sensitivity of the metal detector 100 depends on several variables such as, for example, the position of the aperture 106, the size of the aperture 106, the ability of the metal object being detected to disturb a field, and on the orientation of the metal object inside the aperture 106. FIG. 4 shows a typical sensitivity plot 400 of the field generated within the aperture 106. As shown in FIG. 4, the center region marked "A" has the lowest sensitivity and the lateral region marked "B" has the highest sensitivity. The density of lines of flux 402 indicates a gradient of sensitivity from "A" to "B".

[057] In a metal detection technique, components to be screened for metal contaminants are passed through the aperture 106 that is surrounded by metal coils 104a-c, as shown for example, in FIGS. 1 -2. A subset of the coils 104b generates a known field, with the remaining coils 104a, 104c sensing perturbations in that field. These perturbations create a voltage difference across coils 104a, 104c that is dependent on the size and composition of the object passing through the aperture 106, with larger and more conductive objects causing greater perturbations (and hence higher detected voltages) in the sensing coils 104a, 104c. Metal is detected by exceeding a voltage threshold on the sensing coils 104a, 104c. When the voltage threshold is exceed and metal is detected, the object passing through the aperture 106 at the time of the detection is diverted from the process flow into an alternate stream, which may be a waste stream, for example.

[058] Sensor-enabled dose forms present a unique challenge for metal detection, as the fully assembled components contain a sensor having a small, but detectable, amount of metal in the form of an IC and/or one or more metal materials deposited thereon. As described in connection with FIG. 17, in the case of an I EM type of ingestible event indicator, the IC and metal materials are germane elements of the sensor. Therefore, any metal contaminants present in the sensor-enabled dose form must be detected in the presence of the metals associated with the sensor so as not to reject components without metal contaminants. Accordingly, the metal detection techniques described herein reliably detect metal contaminants above the signal caused by the sensor portion of the dose form.

[059] The experiments and test methods described herein employ a dose form implemented as a compressed tablet. Dose forms, however, should not to be construed as being limited to "compressed tablets". Rather, any suitable dose form can be employed in conjunction with the metal detection techniques described herein. Initial experiments conducted by simply passing a standard compressed tablet containing an sensor through the aperture 106 of the metal detector 100 without orientation or positional control showed a large degree of scatter in the detected signals, as indicated in FIG. 5, and thus cannot be used as a reliable indicator for detecting metal contaminants in the presence of a sensor.

[060] FIG. 5 is a graphical representation 500 of dose forms (e.g., compressed tablets) containing a sensor passed through the aperture 106 of the metal detector 100 without orientation or positional control. The vertical axis represents detected signal strength in Volts (V) and the horizontal axis representing time, with each vertical spike indicating a compressed tablet passing through the aperture, eleven tablets, in the present example. As shown in FIG. 5, the technique of randomly passing components through the metal detector 100 aperture 106 without attention to orientation of the sensor system produces high variability in detected signal strength, from -0.5 to ~15V, and thus is not a preferred technique for detecting metal contaminants in a sensor-enabled dose form. [061] It was noted by way of experimentation, however, that passing sensor-enabled dose forms through the aperture 106 in a predetermined orientation, such as, for example, horizontally versus vertically produced much different detection signals. Accordingly, to control the path and orientation of a sensor-enabled dose form as it passes through the aperture 106 of the detector 100, a guide 600 is coupled (e.g., hooked or otherwise attached) to the aperture 106 to provide orientation control on a fixed track 602, as shown in FIGS. 6 and 7 for example, where FIG. 6 shows an end view of the guide 600 and FIG. 7 shows a side view of the guide 600. The guide 600 enables the sensor-enabled dose form to be orientated and controlled either vertical or horizontally. The guide 600 comprises a track 602 for slidably receiving the dose form comprising an event indicator system. The track 602 comprises a horizontal slot 604 for slidably receiving the dose form comprising an event indicator system in a horizontal orientation and a vertical slot 606 for slidably receiving the dose form comprising an event indicator system in a horizontal orientation. It will be appreciated that the scope of the disclosure is not limited to horizontal or vertical orientations. For example, intermediate orientations between vertical and horizontal may be employed without limitation.

[062] In one aspect, the guide 600 may be formed of plastic or any suitable non-metal material. The dimensions d _a -di are provided as illustrative examples only and should not be construed in a limiting manner. In one aspect, the dimensions d _a -di may be selected as follows, without limitation: d _a = -0.375"; d _b = -0.282"; d _c = -0.256"; d _d = -0.093"; d _e = -0.124"; d _f = -0.700"; d _g = -0.098"; d _h = -10.000"; d; = -0.150". Each of the dimensions d _a - di have a suitable tolerance band. Furthermore, the dimensions, d _a -di can be selected to accommodate any particular dose form such that it can be horizontally or vertically oriented as it passes through the aperture 106 of the detector 100.

[063] FIGS. 8 and 9 illustrate a sensor-enabled dose form (e.g., compressed tablet) containing a sensor 800 (referred to as "sensor-enabled dose form 800" hereinafter) located within a guide 600 in horizontal (FIG. 8) and vertical (FIG. 9) orientations in corresponding horizontal and vertical slots 604, 606. As previously discussed, the horizontal orientation of the sensor-enabled dose form 800 is achieved by locating the sensor-enabled dose form 800 in the horizontal slot 604 and vertical orientation is achieved by locating the sensor- enabled dose form 800 in the vertical slot 606 of the guide 600. FIG. 10 shows placement of the guide 600 inside center of the detector 100 aperture 106. The following discussion describes the effect of position and orientation on detection of the dose form containing an event indicator system signal as it is passed through the aperture 106 of the detector 100.

[064] A single standard sensor-enabled dose form 800 was located within the guide 600 in horizontal and vertical orientations and repeatedly passed through the aperture 106 of the detector 100. The guide 600 was passed through the center and nearly to the right and left edges 1002, 1004 of the aperture 106 (about 3.5cm to the left and right of the center, for example). The sensor-enabled dose forms 800 were passed in both vertical and horizontal orientations at each location (center, left, right). Only sensor-enabled dose forms 800 that trigger an ejection event when the detected signal exceeds the detection threshold are stored to the detector 100 log for subsequent analysis and/or printing. The detector 100 sensitivity was set to its maximum (299), which corresponds to a threshold ejection voltage of about 0.048V.

[065] The signal strengths produced by various sensor-enabled dose forms 800 are shown graphically in FIGS. 1 1 A and 1 1 B and are summarized in TABLE 2 below, where the sensor-enabled dose form 800 are labeled as MIT IEM for short hand notation. Single sensor-enabled dose form 800 samples were passed through the aperture 106 of the detector 100 multiple times. The guide 600 was placed on the left edge, right edge, and center of the aperture 106 of the detector 100. The sensor-enabled dose form 800 samples were passed in both horizontal and vertical orientations. Generally, horizontal orientation was much stronger (~100x) than vertical orientation and the edges of the detector 100 aperture 106 were more sensitive than the center, especially for vertical orientation.

[066] FIGS. 1 1A, B graphically illustrate the effect of position and orientation on the detection signal. FIG. 1 1A is a graphical representation 1 100 of overall orientation effects dominated the signal strength, with horizontally oriented event indicator systems (X's) showing up ~1 OOx stronger than vertically oriented event indicator systems (O's). Position also influences detection for both orientations, with the center being least sensitive. FIG. 1 1 B is a zoomed in graphical representation 1 102 to render the smaller signals obtained from a vertically oriented sensor-enabled dose form more easily visible. It should be noted that only seven of ten passes in the vertical, center position resulted in triggered ejections, so only that data is included in the data set. A horizontally oriented sensor-enabled dose form produced a detection signal strength two orders of magnitude greater than the vertically oriented sensor-enabled dose form, regardless of the left, center, or right position. There was also a smaller positional dependence, with the detector showing more sensitivity towards the edges of the aperture 106. The center, vertical position provided the greatest minimization of signal from the event indicator system, with no detections exceeding 0.1V. The zoomed in plot 1 102 of FIG. 1 1 B shows vertically oriented samples 1 104 passed through the left edge of the aperture 106, vertically oriented samples 1 106 passed through the center of the aperture 106, and vertically oriented samples 1 108 passed through the right of the aperture 106, producing a minimized signal from the sensor-enabled dose form 800.

[067] A similar experiment was conducted by rolling calibration standards down a set track at the left, right, and center of the aperture. A standard is a metal sphere of a known metal type and diameter embedded in a plastic puck of approximately 1 " diameter. Standards of 0.22mm ferrous (FE, e.g., chrome-steel), 0.28mm non-ferrous (NF, e.g., brass), and

0.37mm 316 stainless steel (SS) spheres were used, as they represent the manufacturer's minimum detection specification. The position within the aperture shows no effect on signal strength, as shown in FIG. 12, with most detectable signals showing 0.1V or greater.

[068] FIG. 12 is a graphical representation 1200 showing that position within the aperture 106 did not affect detected signal strength of the spherical standards included with the metal detector 100. The spherical standards were encased in plastic and were passed through the aperture 106 of the detector 100 at least ten times and produced a minimally detectable signal for the various metal types. All the spherical standards showed detection amplitudes between 0.1 -0.2 V. In other words, these samples were not positionally dependent on the path through the aperture 106 of the detector 100. Since signal strength of the standards did not seem to be strongly affected by position in the aperture 106, while the sensor signature could be minimized by orientation and positional control, it was concluded that detection of metal contaminants to level of industry best practices would be feasible as long as position and orientation can be controlled. Passing sensor-enabled dose forms in a first orientation could be used to verify that a sensor is present inside a closed dose form prior to screening for metal contaminants in a second orientation. For example, for a sensor- enabled dose form comprising an I EM type sensor, passing the sensor-enabled dose forms in the horizontal orientation could be used to verify that a sensor is present inside a closed dose form prior to screening for metal contaminants in the vertical orientation. [069] FIG. 13 is a graphical representation 1300 of a comparison of minimum signals generated by sensor-enabled dose forms 800 with minimum signals generated by standards. Spherical standard samples 1302 run through the center of the detector 100 aperture 106 and dose form samples 1304 in center/vertical orientation through the aperture 106 of the detector 100 are plotted where the vertical axis represents Amplitude (V) and the horizontal axis represents sample type. As shown in FIG. 13, all vertically and center oriented sensor-enabled dose form 800 showed lower signal than the minimum standards. Minimal separation between centered/vertically oriented sensor-enabled dose form 800 and 316SS at 0.37mm.

[070] FIG. 14 is a graphical representation 1400 of amplitudes of dose forms (e.g., compressed tablets) containing an event indicator system (X's) and empty skirts (O's) implanted with metal contaminants of known size directly compressed in the tablet.

Standard the compressed tablets containing event indicator systems with event indicator systems (O's) were also included as a control. All metal contaminants except 0.3mm SS spheres were detectable above the detection signal produced by the sensor-enabled dose form 800 baseline. In order to verify that metal particles were detectable within the sensor- enabled dose form 800, components were built with metal spheres of known diameter (0.3mm and 0.5mm) and metal type (FE, NF, SS) embedded into tablets both with and without sensors. To construct these components, the metal BBs were glued to the sensor (e.g., a skirt portion of an event indicator system, for example) with a small amount of hydroxypropyl cellulose glue. The sensors with the BBs attached were then compressed into tablet type dose forms using the standard tableting process for manufacturing tablets containing sensors. Following this step, the sensor-enabled dose forms 800 were tested by passing them through the center position of the aperture 106 in a vertical orientation using the guide 600 as previously discussed. A total of 13 groups of components were tested (2 BB diameters, 3 metal types, with and without ICs, plus one control group of standard dose forms (e.g., compressed tablets) containing an event indicator systems without BBs). The results are illustrated in FIG. 14 and summarized in TABLE 2.

[071] Fifty standard sensors with no BBs (left group) showed a handful of outliers above

0.1V, with 58% passing completely below the detection threshold of 0.048V. Comparing between the compressed tablets containing sensors (O's) and the compressed tablets without sensors (X's), the addition of the sensor adds a small but detectable signal below

1V. Components with 0.3mm FE, 0.3mm NF, and 0.5mm SS BBs showed a -0.05V increase in the mean detected signal when an IC was present in a sensor-enabled dose form. For BBs with larger signals (0.5mm FE and 0.5mm NF), the additional metal from the sensor is not detectable above the noise in the detection signal. For 0.3mm SS BBs, the compressed tablets without a sensor did not trigger any ejections, while the additional metal of the sensor caused all the compressed tablets containing a sensor with 0.3mm SS BBs to be detected.

[072] TABLE 2 is a summary of amplitudes and phases for detected components for the compressed tablets containing an event indicator system with metal spheres of known sizes.

[073 TABLE 2

[074] From this data, setting a threshold of -0.150V provides for minimization of false detections from sensors inside the compressed tablets, while allowing for detection of metal contaminants of the same size range as the detector 100 could sense without the presence of a sensor (0.3mm FE and NF and above, 0.5mm SS). The detection signal produced by 0.3mm SS BBs was not discernible from the sensor detection signal when both were located in the same sensor-enabled dose form. But, dose forms containing just 0.3mm SS BBs and no sensor were not detectable even at the detector's highest sensitivity.

[075] After establishing a baseline with standard sensor-enabled dose forms 800 with and without standard metal contaminants, (e.g., BBs), the sensor-enabled dose forms 800 with BBs were passed through the detector in the same orientation, identical to the experiment previously outlined. The detection of the intentionally contaminated sensors is summarized in TABLE 3.

[076] TABLE 3 summarizes detection of the sensor-enabled dose form 800 without BBs and with sensors and metal BBs after setting the ejection detector threshold to 0.1V. This eliminated detection of a majority of sensor-enabled dose forms that did not contain metal BBs contaminants. Those dose forms that did contain metal BBs were detected with the exception of the 0.3mm stainless steel BBs (0.3mm SS), that lie below the detection limits for this detector. Therefore, by orienting the sensors and proper establishment of baseline and trigger thresholds, sensor-enabled dose forms could be selectively screened for contaminants using a metal detector in a manufacturing process.

[077] TABLE 3

[078] Comparing the data set in TABLE 3 to the data collected on the sensor-enabled dose forms 800 without sensors, e.g., just BBs in TABLE 2 and the detector set to the highest sensitivity, the same metal contaminants were detected, while screening out 98% of the sensor only components. All metal contaminants were detected except the 0.3mm SS, which was not detected at the highest detector sensitivity. Thus, this method will allow for detection at a level approaching the maximum detection limit of the instrument, in line with industry best practices.

[079] Based on the above, metal detection of sensor-enabled dose forms is possible with proper control of the orientation and position of the sensor within the detection aperture to minimize the detection signal produced by the sensor. If the sensor signal is minimized by passing through the aperture 106 of the detector in a center, vertical orientation and a threshold set to eliminate false positives from the sensor, metal contaminants down to

0.3mm for ferrous and non-ferrous and 0.5mm for stainless steel can be screened out. Smaller stainless steel particles may be detectable, but would require spheres of intermediate diameters to be tested.

[080] In one aspect, the horizontal orientation also may be usable to verify the presence of a sensor inside a dose form prior to screening for metal contaminants.

[081] The metal detector system consisted of a CEIA PH21 N metal detector wirelessly connected via BlueTooth, for example, to a computer such as, for example, a Windows XP PC with MD Scope software installed. The MD scope software allows the user to control all detector settings from a command line interface, as well as providing a virtual scope that can be used to visualize the signals from the detector.

[082] Following power up of the detector, connection can be establish to the PC by starting the MD scope software, and selecting the detector (listed by its serial number) under Communications -> Settings, selecting BlueTooth on the right, selecting the device in the list, and connecting. To visualize the signal spikes, an oscilloscope or an oscilloscope mode can be used.

[083] Screen captures may be acquired by pressing a "Freeze" button in the graphical user interface (GUI) (which also may toggle to display "Acquire") to stop the horizontal scroll of the scope screen and click Save. To restart scanning, the "Acquire" button is pressed (which will toggle back to display "Freeze"). The speed of horizontal scroll can be changed under the trace menu, and the vertical resolution can also be changed as well. However, if the signal exceeds the maximum vertical resolution, the signal may be truncated. Therefore it is recommended to set the voltage vertical resolution to a high enough value to contain the entire signal and when saving images. The ejection threshold voltage is shown by the dotted orange line and value in the lower left of the scope screen.

[084] To collect data, the following procedure may be employed:

[085] 1 ) Start MD scope, login and start Oscilloscope F2.

[086] 2) Adjust to low horizontal scroll speed and 1 V/div vertical resolution

[087] 3) Erase existing values (EV)

[088] 4) Run components through aperture

[089] 5) Freeze scope software, and take necessary saves (adjusting the vertical resolution as needed) [090] 6) Print event log and copy/paste to Excel sheet (PL)

[091] 7) Repeat from 2 for subsequent data sets

[092] The amplitude (in dB) and phase reported by the scope were extracted and the amplitudes converted to V.

[093] V _th = exp(9.2656 - 0.04115 * SE) (1 )

[094] where V _th is the minimum threshold voltage for a detection, and SE is the sensitivity setting (from 0 to 299) of the metal detector 100.

[095] Once the threshold voltage V _th is determined, amplitude can be converted from the decibel value to an absolute amplitude using Equation 2.

[096] V _det = V 0 (2)

[097] where V _det is the detected voltage, V _t is the threshold voltage, and L is the signal in decibels.

[098] FIG. 15 is one aspect of a metal detector system 1500. The system 1500 comprises a guide 1502 to position a sensor-enabled dose form 1504 in a predetermined orientation prior to passing through an aperture 1506 of a metal detector 1508. The metal detector 1508 comprises an aperture 1506 for receiving an oriented sensor-enabled dose form 1504 therethrough. The metal detector 1508 generates a detection signal 1510 when the sensor- enabled dose form 1504 passes through the aperture 1506 of the metal detector 1508. A comparator circuit 1512 compares the detection signal 1510 to a predetermined threshold 1514 to determine when a metal contaminant is present in the sensor-enabled dose form 1504.

[099] As previously discussed, the metal detector 1508 comprises at least one coil 1530 driven by an oscillator 1528. In one aspect, the metal detector 1508 may comprise at least two coils, wherein at least one coil is configured to generate a field and the other coil is configured to detect a fluctuation signal in response to receiving the sensor-enabled dose form 1504 through the aperture 1506 of the metal detector 1508.

[0100] As previously discussed, the guide 1502 comprises a track 1516 with a slot to position the sensor-enabled dose form in a predetermined orientation. In one aspect, the track 1516 comprises a horizontal slot 1520 to position the sensor-enabled dose form 1504 in a horizontal orientation. In one aspect, the track 1516 also may comprise a vertical slot 1522 to position the sensor-enabled dose form 1504 in a vertical orientation.

[0101] In one aspect the system 1500 comprises a controller 1524 coupled to the comparator circuit 1512, wherein the comparator circuit 1512 generates a control signal 1526 based on the detection signal 1510. The controller 1524 rejects contaminated sensor- enabled dose forms based on the control signal 1526.

[0102] FIG. 16 is another aspect of a metal detector system 1600. The system 1600 comprises a first track 1602 for orienting a sensor-enabled dose form 1604 in a first predetermined orientation. The system 1600 receives the sensor-enabled dose form 1604 in the first orientation through a first aperture 1606 of a metal detector 1608. The first aperture 1606 comprising at least one coil 1620 driven by an oscillator 1627. A first detection signal 1610 is generated by the metal detector 1608 in response to the sensor- enabled dose form 1604 passing through the first aperture 1606 of the metal detector 1608 in the first predetermined orientation. A first comparator circuit 1626 compares the first detection signal 1610 to a first threshold 1628 and outputs a first control signal 1630 to a controller 1625. In one aspect, in the first stage, the sensor-enabled dose form 1604 may be oriented in a vertical orientation.

[0103] After passing through the first stage 1614, the sensor-enabled dose form 1604 is oriented in a second predetermined orientation. The sensor-enabled dose form 1604 is then received in the second predetermined orientation through a second aperture 1618 of the metal detector 1608. The second aperture 1618 comprising at least one coil 1622 driven by an oscillator 1629. A second detection signal 1624 is generated by the metal detector 1608 in response to passing the sensor-enabled dose form 1604 through the second aperture 1618 of the metal detector 1608 in the second predetermined orientation. A second comparator circuit 1632 compares the second detection signal 1624 to a second threshold 1634 and outputs a second control signal 1636. In one aspect, in the second stage, the sensor-enabled dose form 1604 may be oriented in a horizontal orientation.

[0104] Thus, first and second detection signals 1610, 1624 are compared against first and second thresholds 1628, 1634 by a comparator circuit, e.g., the first and second comparator circuits 1626, 1632. A metal contaminant may be determined to be present in the sensor- enabled dose form 1604 by a controller 1636 based on the difference between the first and second detection signals 1610, 1624 relative to a predetermined threshold. [0105] Having described a metal detector 100 and metal detection techniques for sensor- enabled dose forms 800, the description now turns to a brief description of a typical sensor- enabled dose form 800 that is suitable for testing in the disclosed metal detector 100 in accordance with the disclosed metal detection techniques.

[0106] With reference to FIG. 17, there is shown one aspect of an ingestible device event indicator system with dissimilar metals positioned on opposite ends as system 2030. The system 2030 can be used in association with any pharmaceutical product, as mentioned above, to determine when a patient takes the pharmaceutical product. As indicated above, the scope of the present invention is not limited by the environment and the product that is used with the system 2030. For example, the system 2030 may be placed within a capsule and the capsule is placed within the conducting liquid. The capsule would then dissolve over a period of time and release the system 2030 into the conducting liquid. Thus, in one aspect, the capsule would contain the system 2030 and no product. Such a capsule may then be used in any environment where a conducting liquid is present and with any product. For example, the capsule may be dropped into a container filled with jet fuel, salt water, tomato sauce, motor oil, or any similar product. Additionally, the capsule containing the system 2030 may be ingested at the same time that any pharmaceutical product is ingested in order to record the occurrence of the event, such as when the product was taken.

[0107] In the specific example of the system 2030 combined with the pharmaceutical product, as the product or pill is ingested, the system 2030 is activated. The system 2030 controls conductance to produce a unique current signature that is detected, thereby signifying that the pharmaceutical product has been taken. The system 2030 includes a framework 2032. The framework 2032 is a chassis for the system 2030 and multiple components are attached to, deposited upon, or secured to the framework 2032. In this aspect of the system 2030, a digestible material 2034 is physically associated with the framework 2032. The material 2034 may be chemically deposited on, evaporated onto, secured to, or built-up on the framework all of which may be referred to herein as "deposit" with respect to the framework 2032. The material 2034 is deposited on one side of the framework 2032. The materials of interest that can be used as material 2034 include, but are not limited to: Cu or Cul. The material 2034 is deposited by physical vapor deposition, electrodeposition, or plasma deposition, among other protocols. The material 2034 may be from about 0.05 to about 500 μηη thick, such as from about 5 to about 100 μηη thick. The shape is controlled by shadow mask deposition, or photolithography and etching. Additionally, even though only one region is shown for depositing the material, each system 2030 may contain two or more electrically unique regions where the material 2034 may be deposited, as desired.

[0108] At a different side, which is the opposite side as shown in FIG. 17, another digestible material 2036 is deposited, such that materials 2034 and 2036 are dissimilar. Although not shown, the different side selected may be the side next to the side selected for the material 2034. The scope of the present invention is not limited by the side selected and the term "different side" can mean any of the multiple sides that are different from the first selected side. Furthermore, even though the system is shaped as a square, the system may take the form of any suitable geometric shape. Material 2034 and 2036 are selected such that they produce a voltage potential difference when the system 2030 is in contact with conducting liquid, such as body fluids. The materials of interest for material 2036 include, but are not limited to: Mg, Zn, or other electronegative metals. As indicated above with respect to the material 2034, the material 2036 may be chemically deposited on, evaporated onto, secured to, or built-up on the framework. Also, an adhesion layer may be necessary to help the material 2036 (as well as material 2034 when needed) to adhere to the framework 2032. Typical adhesion layers for the material 2036 are Ti, TiW, Cr or similar material. Anode material and the adhesion layer may be deposited by physical vapor deposition,

electrodeposition or plasma deposition. The material 2036 may be from about 0.05 to about 500 μηη thick, such as from about 5 to about 100 μηη thick. However, the scope of the present invention is not limited by the thickness of any of the materials nor by the type of process used to deposit or secure the materials to the framework 2032.

[0109] Thus, when the system 2030 is in contact with the conducting liquid, a current path, an example is shown in FIG. 19, is formed through the conducting liquid between material 2034 and 2036. A control device 2038 is secured to the framework 2032 and electrically coupled to the materials 2034 and 2036. The control device 2038 includes electronic circuitry, for example control logic that is capable of controlling and altering the conductance between the materials 2034 and 2036.

[0110] The voltage potential created between the materials 2034 and 2036 provides the power for operating the system as well as produces the current flow through the conducting fluid and the system. In one aspect, the system operates in direct current mode. In an alternative aspect, the system controls the direction of the current so that the direction of current is reversed in a cyclic manner, similar to alternating current. As the system reaches the conducting fluid or the electrolyte, where the fluid or electrolyte component is provided by a physiological fluid, e.g., stomach acid, the path for current flow between the materials 2034 and 2036 is completed external to the system 2030; the current path through the system 2030 is controlled by the control device 2038. Completion of the current path allows for the current to flow and in turn a receiver, not shown, can detect the presence of the current and recognize that the system 2030 has been activate and the desired event is occurring or has occurred.

[0111] In one aspect, the two materials 2034 and 2036 are similar in function to the two electrodes needed for a direct current power source, such as a battery. The conducting liquid acts as the electrolyte needed to complete the power source. The completed power source described is defined by the physical chemical reaction between the materials 2034 and 2036 of the system 2030 and the surrounding fluids of the body. The completed power source may be viewed as a power source that exploits reverse electrolysis in an ionic or a conductive solution such as gastric fluid, blood, or other bodily fluids and some tissues. Additionally, the environment may be something other than a body and the liquid may be any conducting liquid. For example, the conducting fluid may be salt water or a metal based paint.

[0112] In certain aspects, these two materials are shielded from the surrounding

environment by an additional layer of material. Accordingly, when the shield is dissolved and the two dissimilar materials are exposed to the target site, a voltage potential is generated.

[0113] Referring again to FIG. 17, the materials 2034 and 2036 provide the voltage potential to activate the control device 2038. Once the control device 2038 is activated or powered up, the control device 2038 can alter conductance between the materials 2034 and 2036 in a unique manner. By altering the conductance between materials 2034 and 2036, the control device 2038 is capable of controlling the magnitude of the current through the conducting liquid that surrounds the system 2030. This produces a unique current signature that can be detected and measured by a receiver (not shown), which can be positioned internal or external to the body. In addition to controlling the magnitude of the current path between the materials, non-conducting materials, membrane, or "skirt" are used to increase the "length" of the current path and, hence, act to boost the conductance path, as disclosed in the U.S. patent application Ser. No. 12/238,345 entitled, "In-Body Device with Virtual Dipole Signal Amplification" filed Sep. 25, 2008 and is incorporated herein by reference in its entirety. Alternatively, throughout the disclosure herein, the terms "non-conducting material", "membrane", and "skirt" are interchangeably with the term "current path extender" without impacting the scope or the present aspects and the claims herein. The skirt, shown in portion at 2035 and 2037, respectively, may be associated with, e.g., secured to, the framework 2032. Various shapes and configurations for the skirt are contemplated as within the scope of the present invention. For example, the system 2030 may be surrounded entirely or partially by the skirt and the skirt maybe positioned along a central axis of the system 2030 or off-center relative to a central axis. Thus, the scope of the present invention as claimed herein is not limited by the shape or size of the skirt. Furthermore, in other aspects, the materials 2034 and 2036 may be separated by one skirt that is positioned in any defined region between the materials 2034 and 2036.

[0114] Referring now to FIG. 18, in another aspect of an ingestible device is shown in more detail as system 2040. The system 2040 includes a framework 2042. The framework 2042 is similar to the framework 2032 of FIG. 17. In this aspect of the system 2040, a digestible or dissolvable material 2044 is deposited on a portion of one side of the framework 2042. At a different portion of the same side of the framework 2042, another digestible material 2046 is deposited, such that materials 2044 and 2046 are dissimilar. More specifically, material 2044 and 2046 are selected such that they form a voltage potential difference when in contact with a conducting liquid, such as body fluids. Thus, when the system 2040 is in contact with and/or partially in contact with the conducting liquid, then a current path, an example is shown in FIG. 19, is formed through the conducting liquid between material 2044 and 2046. A control device 2048 is secured to the framework 2042 and electrically coupled to the materials 2044 and 2046. The control device 2048 includes electronic circuitry that is capable of controlling part of the conductance path between the materials 2044 and 2046. The materials 2044 and 2046 are separated by a non-conducting skirt 2049. Various examples of the skirt 2049 are disclosed in U.S. Provisional Application No. 61/173,51 1 filed on Apr. 28, 2009 and entitled "HIGHLY RELIABLE INGESTIBLE EVENT MARKERS AND METHODS OF USING SAME" and U.S. Provisional Application No. 61/173,564 filed on Apr. 28, 2009 and entitled "INGESTIBLE EVENT MARKERS HAVING SIGNAL

AMPLIFIERS THAT COMPRISE AN ACTIVE AGENT"; as well as U.S. application Ser. No. 12/238,345 filed Sep. 25, 2008 and published as 2009-0082645, entitled "IN-BODY DEVICE WITH VIRTUAL DIPOLE SIGNAL AMPLIFICATION"; the entire disclosure of each is incorporated herein by reference.

[0115] Once the control device 2048 is activated or powered up, the control device 2048 can alter conductance between the materials 2044 and 2046. Thus, the control device 2048 is capable of controlling the magnitude of the current through the conducting liquid that surrounds the system 2040. As indicated above with respect to system 2030, a unique current signature that is associated with the system 2040 can be detected by a receiver (not shown) to mark the activation of the system 2040. In order to increase the "length" of the current path the size of the skirt 2049 is altered. The longer the current path, the easier it may be for the receiver to detect the current.

[0116] Referring now to FIG. 19, the system 2030 of FIG. 17 is shown in an activated state and in contact with conducting liquid. The system 2030 is grounded through ground contact 2052. The system 2030 also includes a sensor module 2074. Ion or current paths 2050 form between material 2034 to material 2036 through the conducting fluid in contact with the system 2030. The voltage potential created between the material 2034 and 2036 is created through chemical reactions between materials 2034/2036 and the conducting fluid.

[0117] FIG. 19A is an exploded view of the surface of the material 2034. The surface of the material 2034 is not planar, but rather an irregular surface 2054 as shown. The irregular surface 2054 increases the surface area of the material and, hence, the area that comes in contact with the conducting fluid.

[0118] In one aspect, at the surface of the material 2034, there is chemical reaction between the material 2034 and the surrounding conducting fluid such that mass is released into the conducting fluid. The term "mass" as used herein refers to protons and neutrons that form a substance. One example includes the instant where the material is CuCI and when in contact with the conducting fluid, CuCI becomes Cu (solid) and CI ^" in solution. The flow of ions into the conduction fluid is depicted by the ion paths 2050. In a similar manner, there is a chemical reaction between the material 2036 and the surrounding conducting fluid and ions are captured by the material 2036. The release of ions at the material 2034 and capture of ion by the material 2036 is collectively referred to as the ionic exchange. The rate of ionic exchange and, hence the ionic emission rate or flow, is controlled by the control device 2038. The control device 2038 can increase or decrease the rate of ion flow by altering the conductance, which alters the impedance, between the materials 2034 and 2036. Through controlling the ion exchange, the system 2030 can encode information in the ionic exchange process. Thus, the system 2030 uses ionic emission to encode information in the ionic exchange.

[0119] The control device 2038 can vary the duration of a fixed ionic exchange rate or current flow magnitude while keeping the rate or magnitude near constant, similar to when the frequency is modulated and the amplitude is constant. Also, the control device 2038 can vary the level of the ionic exchange rate or the magnitude of the current flow while keeping the duration near constant. Thus, using various combinations of changes in duration and altering the rate or magnitude, the control device 2038 encodes information in the current flow or the ionic exchange. For example, the control device 2038 may use, but is not limited to any of the following techniques namely, Binary Phase-Shift Keying (PSK), Frequency modulation, Amplitude modulation, on-off keying, and PSK with on-off keying.

[0120] As indicated above, the various aspects disclosed herein, such as systems 2030 and 2040 of FIGS. 16 and 17, respectively, include electronic components as part of the control device 2038 or the control device 2048. Components that may be present include but are not limited to: logic and/or memory elements, an integrated circuit, an inductor, a resistor, and sensors for measuring various parameters. Each component may be secured to the framework and/or to another component. The components on the surface of the support may be laid out in any convenient configuration. Where two or more components are present on the surface of the solid support, interconnects may be provided.

[0121] As indicated above, the system, such as system 2030 and 2040, control the conductance between the dissimilar materials and, hence, the rate of ionic exchange or the current flow. Through altering the conductance in a specific manner the system is capable of encoding information in the ionic exchange and the current signature. The ionic exchange or the current signature is used to uniquely identify the specific system.

Additionally, the systems 2030 and 2040 are capable of producing various different unique exchanges or signatures and, thus, provide additional information. For example, a second current signature based on a second conductance alteration pattern may be used to provide additional information, which information may be related to the physical environment. To further illustrate, a first current signature may be a very low current state that maintains an oscillator on the chip and a second current signature may be a current state at least a factor of ten higher than the current state associated with the first current signature. [0122] FIG. 20 provides views of various ingestible event marker configurations. Aspects of sensor-enabled dose forms 800 implemented as lEMs may include an assembly unit configured to stably associate one or more ingestible event marker with a carrier, such as a tablet or capsule, to produce an ingestible event marker. Ingestible event markers may have a variety of different configurations. Configurations of interest include, but are not limited to, those shown in FIG. 20, which include various configurations.

[0123] For example, in ΕΜ Identifier-in-Tablet" 1002, an IEM 1006 having a unit 1008, e.g., two dissimilar materials and a control device, and a current path extender ("skirt") 1012 is present inside of a tablet 1004, e.g., by incorporation during tablet pressing or placement in a cavity provided by two tablet halves.

[0124] In "IEM Identifier-On-Tablet" 1014, an IEM 1006 having a unit 1008, e.g., two dissimilar materials and a control device, and a current path extender ("skirt") 1012 is communicably associated with a tablet 1004. A coating 1016, shown in partial form, partially or wholly covers the IEM 1005 and may cover at least a portion of the carrier, e.g., tablet 1004.

[0125] In "IEM Identifier-As-Carrier" 1018, an IEM 1006 having a unit 1008, e.g., two dissimilar materials and a control device, and a current path extender ("skirt") 1012 is communicably associated, e.g., inserted into, a capsule 1020.

[0126] In "Bi-Tablet" 1022, an IEM 1006 having a unit 1008, e.g., two dissimilar materials and a control device, and a current path extender ("skirt") 1012 is communicably associated, e.g., disposed within two tablet-halves 1004a and 1004b, respectively.

[0127] In "On-Capsule" 1026, an IEM 1006 having a unit 1008 is communicably associated, e.g., attached to an exterior portion of capsule 1020.

[0128] In "IEM Identifier-As-Carrier" 1028, an IEM 1006 structure is the tablet or serves as a drug-reservoir matrix. To illustrate, an ingestible event marker includes an integrated carrier structure, where a current path extender ("skirt") serves as drug matrix. By "stably associate" is meant that the one or more markers are physically associated with the carrier component of the ingestible event marker prior to ingestion. A given ingestible event marker may be associated with a carrier, such as a tablet or capsule, using a variety of different approaches. For example, physiological acceptable adhesives, such as thermoset, solvent evaporation, or other types of adhesives may be employed. Alternatively, welding elements, such as tabs or other structures, which can be melted with a high energy stimulus (such as a laser, ultrasonic source, etc.), may be employed to stably associate the ingestible event marker with a carrier. Alternatively, one or more components of the ingestible event marker may be manufactured on a carrier or carrier precursor thereof (such as by use of pulse-jet protocols described in greater detail below) in a manner that stably associates the ingestible event marker with the carrier. Also of interest is the use of ingestible event marker that include structures (such as elastic bands, press-fit structures, etc.) configured to

mechanically interact with a carrier to provide the desired stable association of the ingestible event marker with the carrier. Such structures are elements that mechanically provide for stable association of the ingestible event marker with the pre-made carrier.

Further aspects of the invention are defined in the following clauses:

1 . A method comprising:

orienting a sensor-enabled dose form in a predetermined orientation;

receiving the sensor-enabled dose form through an aperture of a metal detector; generating a detection signal by the metal detector in response to receiving the sensor-enabled dose form through the aperture of the metal detector;

comparing the detection signal to a predetermined threshold; and

determining the presence of a metal contaminant in the sensor-enabled dose form based on the comparison of the detection signal and the predetermined threshold.

2. The method of clause 1 , comprising generating a control signal indicative of detecting the metal contaminant when the detection signal exceeds the predetermined threshold and/or comprising orienting the sensor-enabled dose form in any one of a horizontal orientation, vertical orientation, and any combination thereof.

3. The method of clause 1 or 2, comprising locating the sensor-enabled dose form in a guide comprising a track having a horizontal slot and a vertical slot for positioning the sensor-enabled dose form in a horizontal orientation when the sensor-enabled dose form is located in the horizontal slot and positioning the sensor-enabled dose form in a vertical orientation when the sensor-enabled dose form is located in the vertical slot.

4. The method of any of the preceding clauses, comprising:

orienting the sensor-enabled dose form in a first orientation; wherein generating a detection signal further comprises:

generating a first detection signal in response to receiving the sensor-enabled dose form through the aperture of the metal detector; and

wherein comparing the detection signal to a predetermined threshold further comprises:

comparing the first detection signal to a first threshold to determine the presence of a sensor in the sensor-enabled dose form, the method preferably comprising: orienting the sensor-enabled dose form in a second orientation;

wherein generating a detection signal further comprises:

generating a second detection signal in response to receiving the sensor- enabled dose form through the aperture of the metal detector; and

wherein comparing the detection signal to a predetermined threshold further comprises:

comparing the second detection signal to a second threshold to determine the presence of a metal contaminant in the sensor-enabled dose form.

5. The method of clause 4, comprising:

generating a first control signal indicative of detecting the sensor based on the first detection signal relative to the first threshold; and

generating a second control signal indicative of detecting the metal contaminant based on the second detection signal relative to the second threshold.

6. The method of clause 4 or 5, comprising:

receiving the sensor-enabled dose form in the first orientation through a first aperture of a metal detector;

receiving the sensor-enabled dose form in the second predetermined orientation through a second aperture of the metal detector, different form the first aperture of the metal detector;

generating a first and second detection signal by the metal detector in response to the sensor-enabled dose form passing through the first and second aperture; comparing the first and second detection signals;

determining when a metal contaminant is present in the sensor-enabled dose form based on the difference between the first and second detection relative to a predetermined threshold.

7. The method of any of the preceding clauses, wherein the sensor-enabled dose form comprises an ingestible event indicator system comprising dissimilar metals positioned on different sides of a framework and a control device secured to the framework, wherein the ingestible event indicator system is configured to generate a voltage potential when in contact with a conductive fluid suitable to activate the control device and generate an electrical current through the conductive fluid.

8. The method of any of the preceding clauses, comprising receiving the sensor- enabled dose form in any one of a center, left, or right position relative to the aperture of the metal detector.

9. An apparatus for detecting a metal contaminant in a sensor-enabled dose form, the apparatus comprising:

a guide to position a sensor-enabled dose form in a predetermined orientation;

a metal detector comprising an aperture for receiving an oriented sensor-enabled dose form therethrough, the metal detector to generate a detection signal when the sensor- enabled dose form passes through the metal detector; and

a comparator circuit to compare the detection signal to a predetermined threshold to determine when a metal contaminant is present in the sensor-enabled dose form.

10. The apparatus of clause 9, wherein the metal detector comprises at least one coil or, preferably, wherein the metal detector comprises at least two coils, wherein at least one coil is configured to generate a field and the other coil is configured to detect a fluctuation signal in response to receiving the sensor-enabled dose form through the aperture of the metal detector.

1 1. The apparatus of clause 9 or 10, wherein the guide comprises a track with a slot to position the sensor-enabled dose form in a predetermined orientation, for instance a track with a horizontal slot to position the sensor-enabled dose form in a horizontal orientation and/or a track with a vertical slot to position the sensor-enabled dose form in a vertical orientation.

12. The apparatus of clause 9, 10 or 1 1 , wherein the sensor-enabled dose form comprises an ingestible event indicator system comprising dissimilar metals positioned on different sides of a framework and a control devices secured to the framework, wherein the ingestible event indicator system is configured to generate a voltage potential when in contact with a conductive fluid suitable to activate the control device and generate an electrical current through the conductive fluid.

13. A system for detecting a metal contaminant in a sensor-enabled dose form, the system comprising:

an apparatus according to any of clauses 9-12;

a controller coupled to the comparator circuit.

14. System according to clause 13, wherein the comparator circuit generates a control signal based on the detection signal and wherein the controller is configured to reject contaminated sensor-enabled dose forms based on the control signal.

15. System for detecting a metal contaminant in a sensor-enabled dose form, comprising: a first apparatus comprising:

a guide to position a sensor-enabled dose form in a predetermined orientation;

a metal detector comprising an aperture for receiving an oriented sensor- enabled dose form therethrough, the metal detector to generate a first detection signal when the sensor-enabled dose form passes through the aperture of the metal detector; and

a first comparator circuit to compare the first detection signal to a predetermined threshold and to generate a first control signal based on the first detection signal;

a second apparatus comprising:

a guide to position a sensor-enabled dose form in a predetermined orientation; a metal detector comprising an aperture for receiving an oriented sensor- enabled dose form therethrough, the metal detector to generate a second detection signal when the sensor-enabled dose form passes through the aperture of the metal detector; and a second comparator circuit to compare the second detection signal to a

predetermined threshold and to generate a second control signal based on the second detection signal; and

a controller coupled to the first and second comparator circuits, configured to determine when a metal contaminant is present in the sensor-enabled dose form based on both the first and second control signals, preferably further being configured to reject contaminated sensor-enabled dose forms based on the determination.

[0129] While various details have been set forth in the foregoing description, it will be appreciated that the various aspects of the metal detector apparatus, system, and method may be practiced without these specific details. For example, for conciseness and clarity selected aspects have been shown in block diagram form rather than in detail. Some portions of the detailed descriptions provided herein may be presented in terms of instructions that operate on data that is stored in a computer memory. Such descriptions and representations are used by those skilled in the art to describe and convey the substance of their work to others skilled in the art. In general, an algorithm refers to a self- consistent sequence of steps leading to a desired result, where a "step" refers to a manipulation of physical quantities which may, though need not necessarily, take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It is common usage to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. These and similar terms may be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities.

[0130] Unless specifically stated otherwise as apparent from the foregoing discussion, it is appreciated that, throughout the foregoing description, discussions using terms such as "processing" or "computing" or "calculating" or "determining" or "displaying" or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

[0131] It is worthy to note that any reference to "one aspect," "an aspect," "one

embodiment," or "an embodiment" means that a particular feature, structure, or

characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases "in one aspect," "in an aspect," "in one embodiment," or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more aspects.

[0132] Some aspects may be described using the expression "coupled" and "connected" along with their derivatives. It should be understood that these terms are not intended as synonyms for each other. For example, some aspects may be described using the term "connected" to indicate that two or more elements are in direct physical or electrical contact with each other. In another example, some aspects may be described using the term "coupled" to indicate that two or more elements are in direct physical or electrical contact. The term "coupled," however, also may mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other.

[0133] It is worthy to note that any reference to "one aspect," "an aspect," "one

embodiment," or "an embodiment" means that a particular feature, structure, or

characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases "in one aspect," "in an aspect," "in one embodiment," or "in an embodiment" in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more aspects.

[0134] Although various embodiments have been described herein, many modifications, variations, substitutions, changes, and equivalents to those embodiments may be implemented and will occur to those skilled in the art. Also, where materials are disclosed for certain components, other materials may be used. It is therefore to be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations as falling within the scope of the disclosed embodiments. The following claims are intended to cover all such modification and variations. [0135] Some or all of the embodiments described herein may generally comprise

technologies for an metal detector apparatus, system, and method, or otherwise according to technologies described herein. In a general sense, those skilled in the art will recognize that the various aspects described herein which can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or any combination thereof can be viewed as being composed of various types of "electrical circuitry." Consequently, as used herein "electrical circuitry" includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of random access memory), and/or electrical circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment). Those having skill in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof.

[0136] The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one embodiment, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in component, can be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more

microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware would be well within the skill of one of skill in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a Compact Disc (CD), a Digital Video Disk (DVD), a digital tape, a computer memory, etc.; and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired

communications link, a wireless communication link (e.g., transmitter, receiver, transmission logic, reception logic, etc.), etc.).

[0137] All of the above-mentioned U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, non-patent publications referred to in this specification and/or listed in any Application Data Sheet, or any other disclosure material are incorporated herein by reference, to the extent not inconsistent herewith. As such, and to the extent necessary, the disclosure as explicitly set forth herein supersedes any conflicting material incorporated herein by reference. Any material, or portion thereof, that is said to be incorporated by reference herein, but which conflicts with existing definitions, statements, or other disclosure material set forth herein will only be incorporated to the extent that no conflict arises between that incorporated material and the existing disclosure material.

[0138] One skilled in the art will recognize that the herein described components (e.g., operations), devices, objects, and the discussion accompanying them are used as examples for the sake of conceptual clarity and that various configuration modifications are

contemplated. Consequently, as used herein, the specific exemplars set forth and the accompanying discussion are intended to be representative of their more general classes. In general, use of any specific exemplar is intended to be representative of its class, and the non-inclusion of specific components (e.g., operations), devices, and objects should not be taken limiting.

[0139] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations are not expressly set forth herein for sake of clarity.

[0140] The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can also be viewed as being "operably connected," or "operably coupled," to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable," to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components, and/or wirelessly interactable, and/or wirelessly interacting components, and/or logically interacting, and/or logically interactable

components.

[0141] In some instances, one or more components may be referred to herein as

"configured to," "configurable to," "operable/operative to," "adapted/adaptable," "able to," "conformable/conformed to," etc. Those skilled in the art will recognize that "configured to" can generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise.

[0142] While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.)- It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations.

[0143] In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase "A or B" will be typically understood to include the possibilities of "A" or "B" or "A and B." [0144] With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Also, although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like "responsive to," "related to," or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise.

[0145] In certain cases, use of a system or method may occur in a territory even if components are located outside the territory. For example, in a distributed computing context, use of a distributed computing system may occur in a territory even though components of the system may be located outside of the territory (e.g., relay, server, processor, signal-bearing medium, transmitting computer, receiving computer, etc. located outside the territory).

[0146] A sale of a system or method may likewise occur in a territory even if components of the system or method are located and/or used outside the territory. Further, implementation of at least component of a system for performing a method in one territory does not preclude use of the system in another territory.

[0147] Although various embodiments have been described herein, many modifications, variations, substitutions, changes, and equivalents to those embodiments may be implemented and will occur to those skilled in the art. Also, where materials are disclosed for certain components, other materials may be used. It is therefore to be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations as falling within the scope of the disclosed embodiments. The following claims are intended to cover all such modification and variations.

[0148] In summary, numerous benefits have been described which result from employing the concepts described herein. The foregoing description of the one or more embodiments has been presented for purposes of illustration and description. It is not intended to be exhaustive or limiting to the precise form disclosed. Modifications or variations are possible in light of the above teachings. The one or more embodiments were chosen and described in order to illustrate principles and practical application to thereby enable one of ordinary skill in the art to utilize the various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the claims submitted herewith define the overall scope.