[001] This invention relates to monitoring the administration to a patient of medication doses prescribed by a doctor and contained in an array of blisters of a blister package, each blister containing the prescribed doses to be administered to the patient at the time and on the day denoted by the position of the blister in the array of blisters.

State of the art

[002] The blister packaging of prescribed doses to be administered to a patient is being increasingly used nowadays in place of providing the patient with an assortment of bottles of medication tablets which relies on the patient correctly administering the prescribed medication doses at the times prescribed by a doctor. In effect, the blister packaging of the medication doses by a pharmacist transfers from the patient the responsibility of selecting the different doses to be administered at a particular time on a particular day.

[003] Legend associated with the rows and columns of blisters in the array and printed on the package identifies the day and time at which the medication doses in the blister are to be administered. The blisters are moulded from a plastics sheet which is sufficiently soft and flexible to allow manual pressure exerted by a patient's fingers on a blister to eject the contained medication doses in the blister through an easily-ruptured friable foil covering the back of the blister sheet. The foil serves to seal the blisters and to isolate them from one another. Typically such a blister package will have at least twenty-eight blisters which is sufficient to provide most patients with a week's supply of prescribed medication doses.

[004] Although the blister packaging of prescribed medication doses is a significant step forward in the administration of medication doses, it still relies on the patient to remember to administer the medication doses at the time signified by the position of a blister on the blister sheet. Elderly patients do not always have a good memory and it happens from time-to-time that a blister is not opened at the correct time or that two blisters are opened and their contents administered in quick succession. With modern powerful drugs sometimes being present in the medication, the effect of a patient overdosing or failing to take the prescribed medication doses at the correct time can have serious consequences for the patient. To lessen the risk of this occurring various techniques have been employed to enable the pharmacist who initially prepared the blister package to check that all of the blisters have been opened. Such checking can be carried out by arranging for the patient to return the previously-issued blister package before a new one is issued. If the patient returns a blister package at the correct date but it still has one or more unopened blisters, the lack of compliance with the original prescription will be immediately apparent. Likewise if the patient returns a blister package to the pharmacist a day or so early and with all of the blisters opened, this may also indicate a lack of compliance.

[005] Unfortunately the above techniques for indication a possible lack of compliance do not provide the pharmacist with information indicating when a particular blister was opened and this information might be important for ensuring the good health of the patient. Object of the invention

[006] An object of this invention is to improve the way in which the progressive opening of blisters of a blister package complies with the requirements of a prescription provided by a doctor.

The invention

[007] In accordance with the present invention a holder for storing a blister package between times of use and having manually releasable connections for retaining a stored blister package in a predetermined position, includes an array of sensing elements in the holder and corresponding in the positions of the blisters on the blister package and which respond to a change in a characteristic of a friable foil used to seal the cavities of the blisters, electronic circuitry connected to activate the sensing elements when compliance of the opening of the blisters is to be monitored, and a timer which records in a memory in the holder the time at which a change in the characteristic of the foil sealing a particular blister occurred.

Preferred features of the invention

[008] The preferred characteristic sensed by the sensing elements is the extent to which light is reflected by the foil. A sensing element such as a light-pulse generator in the holder may be activated to direct a pulse of light, such as an infrared light beam, towards the foil. The ruptured regions of the foil reflect a different amount of the incident light back towards the sensing element or some other light-sensitive device, as compared with the regions of the foil which are still intact. The memory can then retain the time at which the chosen characteristic changed and thus the time at which the associated blister was opened. [009] Other characteristics of the foil which change when it is ruptured, may also be used. For example a change in the inherent magnetism of the foil or its electrical properties such as its electrical resistance or induction could be used to detect when a region of the foil is ruptured.

[010] One way of retaining the blister package in the holder is to provide connections in the form of a pair of opposed channels on one pair of sides of the holder shaped to accommodate the marginal edges of the blister package when it occupies a predetermined position in the holder. An electrical switch mounted in one of the channels may be used to prevent activation of the electrical circuitry and sensing elements if the blister package is not occupying the predetermined position. When the blister package occupies the predetermined position in the holder the array of sensing elements respectively coincide with the positions of the blisters in the package and the existence of compliance or noncompliance can be detected.

[011] Suitably the holder is constructed as a flat platen in which the sensing elements and circuitry are embedded. When the blister package is in the predetermined position the foil covering the mouths of its blisters preferably lies against, or is adjacent, a flat surface of the holder.

Introduction to the drawings

[012] One example of the invention will now be described in more detail with reference to accompanying partially diagrammatic drawings, in which :-

In the drawings

FIGURE 1 is a front elevation of a compliance holder for a blister package; FIGURE 2 is a side view of the holder of figure 1 as viewed in the direction of the arrow "B" in figure 1;

FIGURE 3 is a cross-section through the holder of figure 1 taken on the line and in the direction indicated by the arrows II-II in figure 1, the position of the blister package at the predetermined position in the holder being shown in phantom outline;

FIGURE 4 is an end view of the holder as seen in the direction of the arrow "A" in figure 1; and ,

FIGURE 5 is a block schematic diagram of electrical circuitry embedded in the holder of figure 1 and used to detect compliance of the blister package with the requirements of a medical prescription provided by a doctor for the patient identified on the blister package.

Description of preferred example

[013] Figure 1 shows a holder 1 having a flat rectangular central panel 2 made of a hard plastics material and in which is embedded an array of thirty five sensing elements 3 forming part of compliance detection circuitry shown in more detail in figure 5. The elements 3 are arranged in five vertical columns 4 and seven horizontal rows 5. This configuration of the array of elements depicted in figure 1 is just one of a large number of configurations which can be used and is in no way limiting to the operation of the invention.

[014] The panel 2 has two opposed side members 6 and one base member 7. Each of these members is formed with a coplanar channel 8 as is shown in figures 1 and 3. Figure 3 also shows in dotted outline a blister package 10 having three marginal edges 11 which respectively locate in the channels 8. Two further sensing elements 12 are respectively located in opposite ends of the channel 8 of the base member 7 and provide signals when the blister package 10 occupies a predetermined position in the holder at which its compliance can be checked. A pair of straps 13 made of a material such as VELCRO (trade mark) provide attachments located at the tops of the side channels 8 and serve to hold the blister package 10 in the predetermined position during transportation and when measuring its compliance.

[015] Blister packages used in the pharmacy industry to provide prescribed medications to a patient are well-known in the art and therefore will not be described in detail here. However a brief description of such a package may assist the reader. The blister package has a rectilinear array of blisters each containing doses of medication prescribed by a doctor. The position of each blister on the array denotes a particular time on a specific day on which the doses in that blister are to be administered to the patient identified on the upper portion of the blister package. The blisters are moulded out of a soft plastics and generally transparent blister sheet the back of which is covered by an easily-ruptured friable foil backing sheet serving to seal the medication doses into the cavities of the individual blisters. Each of the blisters, being soft, is manually depressible to eject its contents through the region of the backing sheet closing the blister cavity. The portion of the foil surrounding each blister adheres to the coplanar portions of the blister sheet located between the cavities of the blisters so that the opening of one blister will leave the neighboring blisters intact.

[016] Figure 5 shows the electrically circuitry used to detect whether there is compliance of the administration of required medication doses prescribed for a particular patient, with the requirements of a prescription determined by a doctor. The circuitry is embedded in plastics material from which the holder is made [17] The circuitry of figure 5 is powered by a battery 22 but remains de-energised as long as either of the two switches 12 is open. The switches 12 are closed by the insertion of the blister package into a predetermined position in the holder, provided that a master switch 20 is also closed. Control over the master switch 20 is exercised by a pharmacist, or remotely by a signal from a telephone line or other device at times that monitoring of the compliance is to be carried out. If the blister package is not at the predetermined position in the holder the attachments 13 assume positions indicating that the blister package 10 is not properly inserted in the holder 1.

[18] The array of sensing elements 3 shown in figure 1 are individually associated with regions of the backing sheet closing respective blister cavities. The circuitry of figure 5 is energized by the closure of switches 12 and 20 to cause each of the sensing elements 3 to transmit as pulse of light towards the associated region of the backing strip and to sense from the intensity of the reflected light whether there has been a change in the reflective characteristic of the region. If there is ho change, then the blister is intact. On the other hand if the intensity of the reflected light has diminished, this would signify that the blister had been opened.

Operation of the preferred example

[19] The condition of each of the regions of the backing strip is compared by a comparator circuit 26 with the contents of a memory 27. This is set up initially by the doctor's prescription. As long as the condition of the regions at a particular time and date agrees with the information provided by the memory 27 and indicating correct compliance, no signal is sent to an indicator circuit 28. On the other hand, if the condition of a region does not agree with that stored in the memory, this non-compliance condition causes the comparator circuit 26 to send a signal to the indicator circuit 28 which responds by recording the non-compliance of the region in a register 30. Simultaneously the register 30 records the time at which the non-compliance is indicated, this information being obtained from a continuously running timing circuit 23 having its own power source 40.

[20] An interrogator circuit 31 is connected to the register 30 to enable its contents to be down-loaded from time-to-time. Operation of the interrogator circuit 31 permits the contents of the register 30 to be transmitted to a display (not shown) to indicate to a pharmacist whether there has been compliance by the patient with the prescription provided by the doctor. A facility (not shown) may also be provided to enable the contents of the register 30 to be down-loaded and transmitted to a remote location by way of a telephone line, a radio signal or some other means of communication, so that someone at the remote location can monitor the compliance and also, if required, the location of the person so that immediate medical attention can be given if necessary.

[21] The master switch 20 incorporates a time-delay circuit (not shown) preventing it from opening the switches 12 for a predetermined period after interrogation of the register 30 commences. This time delay ensures that the interrogation function of the circuitry of figure 5 can be completed before the battery 22 is disconnected.