Abstract:
Human or animal body fluids can be measured in-vivo to determine analyte concentrations, such as glucose. The measurement system comprises an exchangeable sensor for in-vivo placement, a data carrier with calibration data for the sensor, a housing having a first chamber for receiving a sterile sensor and a second chamber for receiving a data carrier, and a base station that couples to the housing for transmitting measurement signals to an evaluation unit. Replacement sterile sensors can be packaged in a sterile package and the data carrier associated with the replacement sensor can be packaged in a non-sterile package.

Description:
REFERENCE 
       [0001]    This application claims priority to European Patent Application No. EP 07005637.9 filed Mar. 20, 2007, which is hereby incorporated by reference. 
       FIELD 
       [0002]    The disclosure relates to a system for the in-vivo measurement of an analyte concentration in a human or animal body. 
       BACKGROUND 
       [0003]    As a general rule, sensors for the measuring of analyte concentrations of bodily fluids such as, e.g., blood or interstitial fluids cannot be manufactured with exactly preset measuring sensitivities. Typically, considerable deviations occur between production batches. To determine analyte concentrations by means of sensor signals provided by in-vivo measurements with sufficient exactitude for medicinal applications, calibration data are therefore required that were either determined at the pertinent sensor itself or by means of random testing of other sensors of the pertinent production batch. In general, such calibration data describe the difference between an ideal sensor sensitivity and a determined sensor sensitivity. 
         [0004]    Systems for the in-vivo measurement of analyte concentrations typically comprise exchangeable sensors as exchange or consumable components and a long-life base station to which the exchangeable sensors are connected. This brings about the problem that at each exchange of sensor, new calibration data must be made available to the system. 
         [0005]    Calibration data can be made available on a packing leaflet for the sensor and be manually entered by the user into the system. Because this procedure entails, however, the danger of input errors it is more beneficial to accompany each sensor or each sensor package with a data carrier with thereto stored calibration data in order to preclude the risk of input errors. 
         [0006]    However, also this solution is not perfect since the risk exists that data carriers associated with different sensors could be transposed by the users and erroneous calibration data would thus be made available to a system which, in turn, would cause erroneous measuring results. 
         [0007]    The sensors of an in-vivo measuring system must be sterile because they are inserted into the body of a patient. When being packaged together with a data carrier in a single housing, the customary method of sterilization, to wit, an intensive irradiation, entails considerable difficulties. Because electronic or magnetic data carriers are impaired due to the required radiation dose required for sterilization, it is not possible, or only with very expensive, especially manufactured data carriers, to irradiate the sealed housing with the therein arranged sensor and data carrier to sterilize the sensor. 
       SUMMARY 
       [0008]    The in-vivo measurement of an analyte concentration in a human or animal body, comprising exchangeable sensors for generating measuring signals that correlate to the analyte concentration to be measured, data carriers with calibration data of the sensors, a base station to which at least one of the exchangeable sensors and a therewith associated data carrier with calibration data can be connected so that, during operation, measuring signals generated by a connected sensor can be transmitted to an evaluation unit that evaluates the measuring signals generated by the connected sensor by means of the calibration data that were read from the data carrier associated with the connected sensor. The invention relates further to a packaging system for exchange components of such a measuring system and a method for packaging of a sensor and a data carrier in which the sensor&#39;s calibration data are stored. 
         [0009]    An embodiment of the housing is provided with at least two separate chambers wherein in a first chamber at least one of the sensors is arranged in sterile conditions and in the second chamber a data carrier with the calibration data of the sensor, wherein the housing is adapted to an interface of the base station so that the sensor in the housing and the therewith associated data carrier are connectable to the base station by setting the housing to the interface. 
         [0010]    The sensor and the data carrier can be connected to the base station in a single operational step, insofar as the housing in which they are arranged is set to the base interface of the base station adapted to the housing. In such a manner, the risk of transposing data carriers or an erroneous connection of sensors can be effectively met. 
         [0011]    The housing, wherein are arranged at least one sensor and a therewith associated data carrier, can be a packaging housing which is intended to be either totally or partially removed anew from the base station prior to effectuating an in-vivo measurement. However, it is also possible that while in operation, i.e., while performing in-vivo measurements, the housing continues to be connected to the base station. 
         [0012]    The housing has at least two separate chambers. For the packaging of a sensor with a therewith associated data carrier the sensor is, at first, arranged in the first housing chamber, the housing is subsequently sealed and the sensor in the first housing chamber is sterilized by irradiation effect. After the completion of the sterilization process, the data carrier is arranged in the second housing chamber which is then closed. This method for the packaging of a sensor and a therewith associated data carrier is also an aspect of the invention. 
         [0013]    A further aspect of the disclosure relates to a packaging system for exchange components of an in-vivo measuring system, according to the invention; the packaging system comprising a housing with at least two separate chambers, at least one sensor for generating measuring signals, that correlate to the analyte concentration to be measured, and a data carrier with calibration data of at least the one sensor, wherein the sensor is arranged under sterile conditions in a first chamber of the housing and the data carrier with the calibration data of the sensor is arranged in a second chamber of the housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Further details and advantages of the invention are explained by means of embodiments with reference to the attached drawings. 
           [0015]      FIG. 1  shows a schematic representation embodiment of a base station and a thereto connected sensor of a system for the in-vivo measurement of an analyte concentration in a human or animal body; 
           [0016]      FIG. 2  shows the base station of the embodiment illustrated in  FIG. 1  and an embodiment of a packaging system with exchange components to be connected to the base station; 
           [0017]      FIG. 3  shows a packaging system embodiment specified for the connection of the exchange components to the base station; 
           [0018]      FIG. 4  shows an operational step for the manufacture of the packaging system illustrated in  FIG. 2 ; 
           [0019]      FIG. 5  shows another operational step for the manufacture of the packaging system; 
           [0020]      FIG. 6  shows the packaging system with an outer packaging; 
           [0021]      FIG. 7  shows another embodiment of a system, according to the invention, for the in-vivo measurement of an analyte concentration in a human or animal body; 
           [0022]      FIG. 8  shows a cross-sectional illustration of  FIG. 7 ; and 
           [0023]      FIG. 9  shows a sensor housing of the embodiment illustrated in  FIGS. 7 and 8 . 
       
    
    
     DETAILED DESCRIPTION 
       [0024]      FIG. 1  shows a schematic illustration of a base station  2  of a system  1  for the in-vivo measurement of an analyte concentration in a human or animal body with a sensor  3  connected to the base station  2  for generating measuring signals that correlate to the analyte concentration to be measured.  FIG. 1  shows a human or animal body, symbolically represented by the box  4 , into which is inserted the sensor  3  for an in-vivo measurement. In addition to the sensor  3 , the system  1  comprises a battery  5  connected to the base station  2  as another consumable or exchange component. 
         [0025]    The base station  2  is intended to be attached to the body of the patient during the in-vivo measurement and comprises a potentiostat that supplies the connected electro-chemical sensor  3  with electric current and holds a preset value of an electric potential at a measuring electrode of the sensor  3  with respect to the reference electrode of the sensor  3 . The base station  2  also comprises an electronic evaluation unit which, during operation, evaluates by means of calibration data the measuring signals generated by a connected sensor  3 . However, in principle it is also possible to arrange the evaluation unit in a device separate from the base station, to which device the measuring signals are made available by, e.g., radio or a data transfer line. 
         [0026]      FIG. 1  shows connection contacts  6   a ,  6   b ,  6   c  of the base station  2  for connecting of the sensor  3 , and connection contacts  7   a ,  7   b  of the base station  2  for connecting of the battery  5 . The base station  2  has also at least one data input  8   a ,  8   b  for the connecting and the readout of a data carrier with calibration data, which can be removed from the base station  2  after the readout of the calibration data and which, therefore, is not shown in the operating state illustrated in  FIG. 1 . The data input  8   a ,  8   b  is coupled with spring elements  9  which, through elastic force, facilitate the attaching of a data carrier. The data carrier is preferably a storage chip so that the data input is formed by electric connection contacts. By way of example, the data carrier can also be a magnetic data carrier and the data input  8   a ,  8   b  can correspondingly comprise a reader head. 
         [0027]      FIG. 2  is a schematic illustration of the shown base station without connected exchange components. Additionally,  FIG. 2  shows schematically a packaging system  10  for the exchange components (in particular, sensor  3 , battery  5  and data carrier  11  with calibration data) which, together with the base station  2 , constitute a system  1  for the in-vivo measurement of an analyte concentration in a human or animal body. The packaging system  10  comprises a housing  12  with at least two separate chambers  13 ,  14 ,  15 , wherein in the first chamber  13  is arranged under sterile conditions the sensor  3  and in a second chamber the data carrier  11  with calibration data of the sensor  3 . In the illustrated embodiment, the battery  5  is arranged in a third chamber  15 . 
         [0028]    The housing  12  is fastened to an interface of the base station  2  in such manner that the sensor  3 , arranged in the housing  12  and the therewith associated data carrier  11 , can be connected to the base station by setting the housing  12  to the interface.  FIG. 3  illustrates schematically the setting of the housing  12  to the interface of the base station  2  for the connecting of the exchange components  3 ,  5 ,  11 . The measuring system  1  is automatically initialized by connecting the exchange components  3 ,  5 ,  11  and the measuring process is initiated. 
         [0029]    For connecting the exchange components  3 ,  5 ,  11  arranged in the housing  12 , the housing  12 , in particular the sterile housing chamber  13 , is opened. To facilitate the opening, the housing  12  of the illustrated embodiment is provided with a rupture joint  16  so that a user can easily break off a housing part  17 , which seals the chambers  13 ,  14 ,  15 , from the housing  12 . This breakable housing part  17  can be configured, e.g., as a cap. In the herein illustrated embodiment, the housing part  17  seals both the sterile chamber  13  in which is housed the sensor  3  as well as the chambers  14 ,  15  wherein are arranged the data carrier  11  and the battery  5 . It is, however, also possible to seal these chambers  13 ,  14 ,  15  by means of separate housing parts that must be removed separately. In particular, for the sealing of non-sterile chambers, e.g., the chambers  14 ,  15 , housing the data carrier  7  or the battery  5 , a removable sheeting or the like can also be used. 
         [0030]    The housing  12  is provided with a spring element  20  that facilitates the connecting of the battery  5  when the housing  12  is set to the interface of the base station  2 . Correspondingly, spring elements can also be arranged in the first chamber  13  and in the second chamber  14  to facilitate connecting of the sensor  3  and/or the data carrier  11  to the base station. 
         [0031]    In the illustrated embodiment, the housing  12  and the interface of the base station  2  are adapted to each other in such a manner that, when the housing  12  is set to the interface, the battery  5  and the data carrier  11  are connected to the base station first and it is only afterwards that the sensor  3  is connected to the base station  2  by means of the thereto provided contacts  6   a ,  6   b  and  6   c . In the illustrated embodiment, the sensor  3  has a flat structure and is connected to the base station  2  by means of a zero force plug  3   a . The sensor  3  can also have, e.g., a sandwich structure or be configured rotationally symmetrical with the contacts  6   a ,  6   b  and  6   c  being adapted thereto. 
         [0032]    A seal  21  of the base station  2 , which in the illustrated embodiment is configured as a sealing ring, provides for a watertight coupling of the sensor  3  to the base station  2 , so that no moisture can infiltrate into the inside of the base station  2 . Thus, by way of example, the base station  2  can be placed on the abdomen of a patient without risk of being damaged by bodily fluids. The seal  21  effectuates a highly resistive sealing of the base station  2  and of the thereto connected sensor  3 . In such a manner, the sensor  3  can be supplied with power as being an electro-chemical sensor by means of a potentiostat without being impaired by leakage currents. 
         [0033]    In the illustrated embodiment, the housing  12  is configured as a blister packaging. Compartments are formed in the plastic portion of the blister packaging that form the bottom and the walls of the chambers  13 ,  14 ,  15  of the housing  12 . In a first operational step, illustrated in  FIG. 4 , a sensor  3  is arranged in the first housing chamber  13  whereupon the chamber  13  is sealed. Subsequently, the sensor  3  in the housing chamber  13  will be sterilized by irradiation. Especially appropriate are electron rays e with a dose of at last 20 kGy. In particular, especially appropriate is an electron ray dose of 28 kGy. 
         [0034]    In another operational step, illustrated in  FIG. 5 , the data carrier  11  is described with calibration data  30  of the sensor  3  arranged in the first housing chamber  13 . These calibration data  30  are determined by means of random checks of the same production batch after conclusion of the sterilization process. Thereupon, the data carrier  11  is arranged in the second housing chamber  14  and the battery  5  in the housing chamber  15 . Then the housing chamber  14 , is sealed. The housing chambers  13 ,  14 ,  15  can be sealed in the customary manner in the blister packaging, e.g., by means of a plastic or metal sheeting. 
         [0035]    In a last step, the completed packaging system  10  is packed in an outer packaging, in which it is sold, e.g., welded into a plastic sheet.  FIG. 6  illustrates such a packaging system  10  with an outer packaging  31 . 
         [0036]    In the case of the embodiment explained above through  FIGS. 1 to 6 , the housing  12 , containing the exchange components, is a packaging housing which is intended to be removed from the base station  2  prior to the carrying out of an in-vivo measurement. Hereinafter, by means of  FIGS. 7 to 9  is explained another embodiment, wherein the housing  12 , containing the exchange components, is fixed to the base station  2  during the carrying out of the in-vivo measurement. 
         [0037]      FIG. 7  shows in a diagonal view the base station  2  with thereto attached housing  12  that contains the exchange components of system  1 .  FIG. 8  shows a cross-sectional view of  FIG. 7  with the sterile housing chamber  13  with the therein arranged sensor  3  as well as the second housing chamber  14  with therein arranged battery  5  and data carrier  11  wherein are stored the calibration data of the sensor  3 . The base station  2  is provided with a potentiostat  48  for the current and power supply of sensor  3  and an evaluation unit  47 , configured as a microprocessor which, during operation, evaluates the measuring signals generated by the connected sensor  3  by means of the calibration data that were read from the data carrier  11  associated with the sensor  3 . In principle, however, the potentiostat  48  can also be configured as a consumable component and arranged together with the sensor  3  in the housing  12 , so that regarding high electrical resistance lower requirements can be placed on the sealing of the base. Furthermore, the evaluation unit  47  can be arranged in a device separate from the base station  2 , which device can receive the data from the base station  2 . 
         [0038]    The housing  10  of the packaging system for consumable components is manufactured out of rigid plastic, alike to that of the base station  2 . In the illustrated embodiment, the interface of the base station  2  and the housing  12  containing the consumable components are configured for an interlocking connection. The housing  12  is provided with drop-in lugs  40  that engage in thereto adapted recesses of the interface of the base station  2 . These recesses are provided on the outsides of two spring legs  41  so that, by elastic force, the drop-in lugs are pressed into the recesses. The spring legs  41  can be compressed, so that the drop-in lugs  40  of the housing  12 , containing the consumable components, are released from the thereto adapted recesses and the housing  12  can be removed from the base station  2 . In a corresponding manner, with the spring legs  41  being compressed, the housing  12 , containing the consumable components, can be fastened to the base station  2 . 
         [0039]    Alternatively or additionally to an interlocking connection, the housing containing the consumable components can be also configured in such a manner that, for the connecting of the sensor arranged in the housing, it can be fastened to the base station  2  by means of clamping. 
         [0040]    The cross-section illustrated in  FIG. 8  shows that the housing  12  is provided with two separate chambers  13 ,  14 , wherein in a first chamber  13  the sensor  3  is arranged under sterile conditions and that, in the second chamber  14  are arranged a data carrier  11  with the calibration data of the sensor  3  and a battery  5  for the power supply of the base station  2 . Connecting leads of the sensor  3  extend from the first chamber  13  into the second chamber  14  to a circuit board  45  that is connected to the data carrier  11  configured as a storage chip. The circuit board  45  is connected to the base station  2  by means of a plug connection  46 , which in the illustrated embodiment is a multi-pole plug connection. 
         [0041]    The sterile chamber  13 , which contains the sensor  3 , is sealed by two septa  42 , whereby an insertion needle  43  for insertion of the sensor  3  into a human or animal body passes through the septa  42 . The front end of the insertion needle  43  protruding from the chamber  13  is covered by a sterile protection cap  44  that is removed only when, by means of the insertion needle  43 , the sensor  3  is to be inserted into the human or animal body. In the illustrated embodiment, the sterile protection cap  44  is fastened together with the rest of the housing  12  to a rupture joint  16 . 
         [0042]    To insert the sensor  3 , the system  1 , assembled from the packaging system and the base station, is placed, e.g., on the abdomen of a patient and the insertion needle  43  is stuck into the body of the patient. Subsequently, the insertion needle  43  that is configured, e.g., as a conduit carrying the sensor  3 , can be withdrawn from the body of the patient while the sensor  3  remains inside the body of the patient. 
         [0043]    For the packaging of the sensor  3  and a data carrier  11 , in which are stored the calibration data of the sensor  3 , the sensor  3  is first arranged in the first housing chamber  13  which is then sealed. For the manufacture of the embodiment illustrated in  FIG. 8  in this operating step a sterile protection cap  44  is placed the end of the sensor  3  protruding from the first housing chamber  13  and the insertion needle  43  carrying the sensor  3 , and the sterile protection cap  43  is connected to the housing chamber  13 . Subsequently, the housing chamber  13  is subjected to an intensive electron radiation, so that the sensor  3  and the insertion needle  43  are be sterilized.  FIG. 9  illustrates a detailed view of the first housing chamber  13  with the thereto affixed sterile protection cap  44  which, after the arranging of the sensor  3 , are sterilized together by radiation. 
         [0044]    In another operational step, the first housing chamber  13  is assembled with the second housing chamber  14  in order to create the housing  12  containing the consumable components and, thus, the above described packaging system  10  for the consumable components of the measuring system  1 . 
         [0045]    Thus, embodiments of the system for in-vivo measurement of an analyte concentration are disclosed. One skilled in the art will appreciate that the teachings can be practiced with embodiments other than those disclosed. The disclosed embodiments are presented for purposes of illustration and not limitation, and the invention is only limited by the claims that follow.