Abstract:
The drug compliance monitoring system provides a patient with a portable medication dispenser programmed with medication-taking data. The dispenser alerts the patient to take a dose of medication and gathers compliance data relating to the medication-taking data. The compliance data is accessible to a physician, or other care givers, etc., via a network database.

Description:
This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 60/411,013 filed on Sep. 26, 2002, for PRESCRIPTION DRUG COMPLIANCE MONITORING SYSTEM, which is incorporated by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to healthcare monitoring systems and methods and, more particularly, to a system and method for dispensing and monitoring medication for healthcare treatment. 
   A 1995 American Association of Retired Persons study reported that Americans age 65 and older are taking an average of 2.4 prescription drugs, while those age 50-64 take an average of 1.7 prescription drugs. It is also reported that 40% of those failed to follow their physician&#39;s dosage instructions. The Healthcare Compliance Package Council states that of the 1.8 billion prescriptions per year dispensed in the U.S., 50% are not correctly taken. The article that discussed this topic was featured in the September 1998 edition of the Packaging Digest Magazine. From the same source it is also reported that more than 80% of the current 36.3 million people over age 65 in the United States, a number that is sure to increase, are on some type of prescription medication-taking regimen. According to the National Medical Expenditure Survey, in 1987, 90 million Americans suffered from one or more chronic conditions. Treatment of these chronic conditions represents over 76% of healthcare expenditures, and the total direct cost of treating these chronic conditions is estimated to rise to $798 billion in 2030. 
   These statistics clearly depict the usefulness of a system to help patients comply with their medication-taking regimen while limiting their risk of potential adverse complications. As a result of compliance, the patient is in a better position to control their treatment recovery time. Remembering to accurately take medication on time and correctly is well understood to be a very serious health problem, particularly for the elderly and patients with chronic conditions for whom the intake of many different drugs is common. Failure to comply with medication-taking regimens is associated with deterioration of health status, as well as an increase in preventable fatalities. The annual cost related to non-compliance with medication-taking regimens was estimated to be in excess of $100 billion in 1998. 
   The drop off rate for refilling medications for chronic diseases is very high, with up to 75% of monthly prescriptions not refilled after one year. Forgetfulness to self-administer the prescribed medication at the correct intervals and correct dosages by the patients has long been found to be a major hurdle for doctors in determining the effectiveness of prescriptions. It is also well known that the more frequently a medication must be taken, the more likely the patient&#39;s compliance rate will drop. For patients who must take three, four or even five dosages of several medications daily, the prescribed regimen can easily become confusing. Many patients resort to carrying daily timetables—pill containers that sort out the medication by day of the week, or they even rely on somebody else to tell them when to take their medication. This can be effective but does not eliminate the possibility of the patient becoming distracted or simply forgetful in addition to the lack of a reliable compliance record. 
   Various devices for assisting patients in following medication-taking regimens are known. For example, U.S. Pat. No. 6,294,999 to Yarin et al. describes a smart tray with a plurality of medication containers equipped with electromagnetic tags that provides various information about medication contained within a respective container. The smart tray is equipped with a processor and reader that interrogates each respective electromagnetic tag to identify medication contained within each container. Using the retrieved information, a smart tray provides visual and/or audio signals to a patient to remind the patient when and how much of various medicaments to take. The device can also communicate with one or more third parties, such as healthcare providers, pharmacies, and other suppliers of healthcare products and services via a computer network. In addition, a smart tray can communicate with various appliances and can modify medication regimens for particular situations in response to data received from various appliances. 
   U.S. Pat. No. 5,020,037 to Raven discloses an alarm pillbox which cancels the alarm when a compartment lid is opened. A visual display is used to indicate the number of times that the lid has been opened within one day. 
   U.S. Pat. No. 5,408,443 to Weinberger describes a medication-dispensing system that includes a prescribing data entry station for use by a physician to store prescription information in a portable prescribing module, a dispensing data entry station for use by a pharmacy to store dispensing information in a portable dispensing data storage unit, and a medication dispenser responsive to information stored in the portable prescribing module to describe use of medication in the dispenser in accordance with a regimen prescribed by the physician and to the dispensing data storage unit to control dispensing of the medication. One embodiment has two medication drawers each having a plurality of compartments with indicating lights selectively indicating the compartment from which medication is to be taken, a screen for displaying instructions regarding loading of the medication compartments and taking of the medication, and a keyboard for confirming compliance with the instructions. Another embodiment has a series of medication-containing compartments, each covered by a separate sliding or folding cover. 
   U.S. Pat. No. 4,911,327 to Shepherd et al., describes a dispenser for providing scheduled dosages of pills according to a predetermined medication program. A housing contains a plurality of pill containers from which dosages of pills may be released into a user-accessible pill receiver. The release of pills is controlled such that pills are released at predetermined intervals as dictated by the medication program. On release of a dosage of pills, an alarm is activated to indicate to a user that a dosage is due to be taken, the alarm being deactivated when the user accesses the pill receiver to remove the dosage of pills. If the user does not access the pill receiver within a predetermined time interval from release of the dosage, an optional remote alarm may be activated to alert a supervisor. 
   U.S. Pat. No. 5,239,491 to Mucciacciaro describes a holder having a plurality of recesses for holding a plurality of medication containers, each fitting into a unique recess. The geometry of the bottom of each medication container is unique and only matches one recess in the holder. A sensor in each recess signals the presence or absence of the dedicated container to a microprocessor. The microprocessor is programmed with the prescribed dose administration schedule for each of the different medications in the different containers. A real time clock cooperates with the microprocessor and the program to signal audibly and visibly by a light in the appropriate container when a particular pill should be administered. The signals stop when the appropriate container is removed from its recess. A different warning sound indicates when the wrong container is lifted. 
   U.S. Pat. No. 4,837,719 to McIntosh describes a medication clock for signaling the times that dosages of a medication should be taken. The McIntosh device also provides a record of when each medication was taken for comparison with the medication schedule. In addition, the McIntosh device can monitor and record temperature, blood pressure and pulse rate of the user. 
   U.S. Pat. No. 4,616,316 to Hanpeter et al. describes a medication compliance monitoring system consisting of a blister pack having an array of plastic blisters defining compartments for medication. The blister pack has a frangible non-conductive backing sheet including conductive traces behind the compartments, which are respectively ruptured when the medication doses are removed. An electronic memory circuit detects when individual compartments are ruptured and stores this information. 
   E-pill (www.epill.com) offers a pager system that sends reminders to patients to take their medication at a specific time of the day. Carebridge (www.carebridge.net) provides an electronic timing device that patients can use to help them remember to take their medication. 
   IBV Technologies (Seattle, Wash.) provides a medication vial that records the time a patient takes his/her medication when a button is pressed by the patient. When returned to a pharmacy for a refill, the pharmacist can download and review a compliance report from the vial and counsel the patient regarding medication compliance. 
   APREX (Union City, Calif.) provides a telemedline service for monitoring medication compliance. Patients take their medication from medication containers outfitted with caps that have a microcomputer therein. When patients remove the cap from a bottle to take a dose of the medication contained therein, the microcomputer records the time and date of the dosing event. At the end of the day, patients place their medication bottles on a specially configured modem that transmits daily dosing information to a selected healthcare provider. If the healthcare provider detects a problem in how or when patients are taking their medication, specially trained healthcare providers call those patients the next day. 
   The MediMonitor, available from InforMedix, Inc. (Rockville Md.), is configured to retain a month supply of up to five medications in individual compartments and alerts patients when and how to take the medications. The MediMonitor also monitors medication use and health status by providing a date and time-stamped record of a patient&#39;s medication-taking behavior together with patient responses to specific questions. MediMonitor can transmit information via an internet-accessible server and database to clinical drug trial sites, physicians, pharmacies and other healthcare providers. Healthcare providers can communicate information, as well as reminders and specific instructions, directly to patients via the MediMonitor. 
   Unfortunately, existing devices for assisting patients in following medication-taking regimens can be somewhat non-accessible to the public due to price and difficult to use because of their complexity. Furthermore, existing devices for assisting patients in following medication-taking regimens can seem somewhat intrusive to a user. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is directed to a system and method for aiding with compliance of a medication-taking regimen and improving self-reliance and independence of patients. A base station and portable cap assembly attached to a medication container assist the user in remembering to take medication at different period intervals during the course of complying with a medication-taking regimen. The system is also capable of storing in memory the specific time and date of an event for later retrieval by a care giver. 
   The present invention may facilitate compliance with medication regimens, especially complex regimens involving multiple medications. As such, the present invention may reduce medication errors made by patients such as forgetting to take a dosage, confusing dosage times, taking more medication or various combinations thereof. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram of the medication compliance system. 
       FIG. 2  is a block diagram of the preferred embodiment of the medication compliance device. 
       FIG. 3  is a Main Menu screen. 
       FIG. 4  is a System screen. 
       FIG. 5  is a Set Time/Date screen. 
       FIG. 6  is a Set Care giver Phone # screen. 
       FIG. 7  is a Set ISP Information screen. 
       FIG. 8  is a System Info screen. 
       FIG. 9  is a Select Patient screen. 
       FIG. 10  is a Patient Medication screen. 
       FIG. 11  is a Medication History screen. 
       FIG. 12  is a Medication Detail screen. 
       FIG. 13  is an exploded view of the portable medication dispenser. 
       FIG. 14  is a side view of the portable medication dispenser. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows medical compliance system  10  of the present invention. System  10  includes portable medication dispenser  12  having cap  14 , collar  16 , and container  18 ; communication link  20 ; base station  22  having LCD  24  and user interface keys  26 ; communication link  28 ; network  30 ; line  32 ; data server  34 ; communication link  36 ; remote terminal  38 ; communication link  40 ; remote terminal  42 ; line  44 ; and programming base  46 . 
   Dispenser  12  is comprised of cap  14  which is removably attached to collar  16 . Collar  16  is removably connected to the opening of container  18 . Three dispensers  12  are shown in  FIG. 1 . One is shown with cap  14  attached to collar  16 . Two are shown with cap  14  detached from collar  16 . 
   Cap  14  communicates with base station  22  by communication link  20 . Base station  22  has LCD  24  and a bank of user interface keys  26 . Base station  22  communicates with data network  30  via line  28 . Data network  30  is also linked to data server  34  by line  32 , remote terminal  38  by line  36 , and remote terminal  42  by line  40 . Remote terminal  42  communicates with programming station  46  through line  44 .  FIG. 1  also includes an inverted container  18  attached to collar  16 , which couples to programming station  46 . 
   For simplicity, the present invention will be described in the context of a physician prescribing a medication to a patient. However, the invention may be used by any party wishing to induce and/or track a person&#39;s compliance with a medication-taking regimen. 
   In operation, collar  16  contains memory and is connected to container  18  and then coupled with programming station  46  such that medication-taking data is downloaded to collar  16 . Medication-taking data includes a medication-taking regimen and prescription information, the patient&#39;s name, the physician&#39;s name, or any other data that may be required. The physician calls the prescription in to a pharmacist that is equipped with remote terminal  42  linked to programming station  46 , or the details of the prescription may be entered manually by the care giver or pharmacist. The pharmacist inserts collar  16  into programming station  46  and enters the medication-taking data into remote terminal  42 , which subsequently downloads the data through line  44  and programming station  46  to collar  16 . The connection represented by line  44  is preferably an interface cable making contact between remote terminal  42  and programming station  46 . Container  18  is subsequently filled with medication, cap  14  is attached to collar  16 , and dispenser  12  is given to the patient. 
   Cap  14  contains a microcontroller, an indicator, a sensor, and communication means. The microcontroller accesses the medication-taking regimen stored in the memory of collar  16 , when the two are attached, to activate the indicator when the patient should take a dose of medication. It also gathers compliance data from the sensor, which senses if the patient is complying with the medication-taking regimen. The compliance data is also stored in the memory of collar  16 . 
   The patient is equipped with base station  22 . When linked by link  20 , cap  14  transmits the medication-taking data along with the compliance data to base station  22 . Preferably, link  20  is a form of wireless communication, such as infrared light emitting diode, radio frequency, near magnetic field, etc. Base station  22  then transmits the compliance data through line  28  to network  30 , which uses data server  34  to store all of the data. Line  28  may be any type of link for communication with a network, such as the Internet, Intranet, a Wide Area Network (WAN), or a Local Area Network (LAN). 
   The physician can subsequently access the compliance data from a remote location. The physician uses remote terminal  38  to access the data from network  30  through link  36 , which again is any type of communication link. Thus, an outside party, such as a physician, can determine if the patient is complying with the medication-taking regimen. In an alternative embodiment, remote terminal  42  may be used to both input the medication-taking data to collar  16  and access the compliance data. In either instance, access to compliance data is greatly simplified for both the physician and patient. 
     FIG. 2  shows a block diagram of cap  14 , collar  16 , base station  22 , and programming station  46 . Cap  14  and collar  16  form a portable cap assembly. Collar  16  includes memory  48  and connectors  50  and  52 . Cap  14  includes microcontroller  54 , connector  56 , IR transmitter  58   a , IR receiver  58   b , sensor  60 , battery  62 , audio indicator  64 , and visual indicator  66 . Base station  22  includes LCD  24 , user interface keys  26 , modem  28   a , interface  28   b , microcontroller  68 , IR transmitter  70   a , IR receiver  70   b , power supply  72 , speaker  74 , LED  76 , and back up battery  78 . Programming station  46  includes interface  44   a , microcontroller  80 , power supply  82 , connector  84 , power LED  86 , and status LED  88 . 
   The patient keeps base station  22  at their residence. Power supply  72  powers base station  22  through an AC outlet, and backup battery  78  when power is cut off. Base station  22  has either or both modem  28   a  and interface  28   b  for connection to network  30 . Various screens are displayed on LCD  24  for programming and displaying data and instructions for complying with the medication-taking regimen. These are discussed in further detail below. 
   A pharmacist receives a prescription for a medication-taking regimen from a physician. Collar  16  is detached from cap  14  and placed adjacent the opening of container  18 . Collar  16  comes in a variety of sizes to accommodate various sized openings of containers  18 , and both collar  26  and container  18  are disposable and are only used once. Container  18  with collar  16  is then coupled to programming station  46  ( FIG. 1 ), which is linked to remote terminal  42  via interface  44   a . Collar  16  and programming station  46  communicate via connectors  50  and  84 , respectively. Connector  50  is preferably a 4-pin connector. Power LED  86  indicates whether there is adequate power to supply programming station  46 , and status LED  88  indicates whether collar  16  is properly inserted into programming station  46 . 
   The pharmacist inputs the medication-taking data to memory  48  of collar  16 . Container  18  is filled with a medication, and cap  14  is attached to collar  16 . Cap  14  is reusable and can be used for more than one use. Dispenser  12 , consisting of container  18 , collar  16 , and cap  14 , is given to the patient. In an alternative embodiment, the pharmacist may be able to download the medication-taking data to base station  22 , which would subsequently transmit the information to dispenser  12 . 
   The patient places dispenser  12  in the vicinity of base station  22  so that cap  14  communicates with base station  22  through wireless communication link  14  ( FIG. 1 ). Preferably, wireless communication is via an infrared light emitting diode. To this end, cap  14  is equipped with IR transmitter  58   a  and IR receiver  58   b , and base station  22  is equipped with IR transmitter  70   a  and IR receiver  70   b . Any type of communication link may be used, but wireless communication is preferred. All of the medication-taking data is transmitted to base station  22 . 
   Collar  16  and cap  14  communicate through connectors  48  and  56 , respectively. Battery  62  powers cap  14 . Microcontroller  54  reads and carries out the medication-taking regimen stored in memory  48 . When it is time for the patient to take a medication, either or both of audio indicator  64  and visual indicator  66  are activated. Indicators may be of any type that will alert the patient that a dose of medication should be taken and include audio, visual, and tactile indicators. Indicators  64  and  66  are activated for 15 minutes or until sensor  60  receives a signal indicating compliance. Preferably, audio indicator  64  is a buzzer that emits a 200 ms buzz every 30 seconds, and visual indicator  66  is an LED that blinks at a rate of 1 Hz, 25% duty cycle. Either of indicators  64  and  66  may also indicate low battery life. 
   When cap  14  is within range of communicating with base station  22  and it is time to take a dose of medication, cap  14  instructs visual indicator  76  to activate similarly to visual indicator  66 . Accordingly, audio indicator  74  is instructed to activate similarly to audio indicator  64 . Base station  22  may also be equipped with a speaker, not shown, that provides a synthesized voice to remind the patient to take their medication. 
   If the patient takes the medication within the allotted time for compliance, sensor  60  senses that a dose of medication was taken. Microcontroller  54  notes that a dose of medication was taken and stores the date and time in memory  48 . In most cases, sensor  60  detects inferentially that a dose of medication was taken by noting some form of handling of container  18 . For example, sensor  60  may detect the opening/closing of dispenser  12  or that dispenser  12  was inverted. Any means for sensing and generating a detectable electrical signal may be used. 
   If sensor  60  does not sense that a dose was taken, microcontroller  54  notes that the patient did not comply with the medication-taking regimen. The time of non-compliance is noted and stored in memory  48 . If the missed medication dose is taken at a later time, that time is noted and stored in memory  48 . Data from sensor  60  is the compliance data, which is subsequently transmitted to base station  22 . 
   Base station  22  has user interface keys  26 , preferably four keys adjacent to LCD  24 , for navigating the various screens. Keys  26  operate as soft keys, such that the function of each key changes based on the screen that is displayed. After a power-up and a splash screen are displayed, a Main Menu screen is displayed as shown in  FIG. 3 . The Main Menu screen always updates the current date and time. The Main Menu screen also shows messages to the patient when necessary (i.e. George Bush take 2 tablets of Claritin). 
   When the patient presses the System key on the Main Menu screen, the System screen shown in  FIG. 4  is displayed. The System screen lists various system settings that the patient can edit. One system setting in the list is highlighted at a time, and Up Arrow and Down Arrow keys move the highlight up and down the list, respectively. The Main Menu key returns to the Main Menu screen. 
   To set the time and date, the patient moves the highlight to “time/date” and presses the Select key. The Set Time/Date screen is displayed as shown in  FIG. 5 . The patient presses the Right Arrow key to move the highlight through the modifiable fields. When the patient presses the + key and − key, the currently highlighted field will change values accordingly. 
   The patient chooses between a 12 hour or 24 hour format, selects the correct time zone, and sets the date and time for the real time clock chip that is part of microcontroller  68 . Once the real time clock is set, the patient presses the Ok key to update the time settings and return to the System screen. Base station  22  may also be programmed to retrieve the time and date from server  34  once it is plugged into network  30 . 
   Next, from the System screen, the patient selects “care giver phone #,” and the Set Care giver Phone # screen is displayed, as shown in  FIG. 6 . The Set Care giver Phone # screen displays the telephone number of the primary care giver in case they need to be contacted. When initially entered, the first character of the area code is highlighted. The patient presses the + key and − key to change the value of the highlighted character. The Right Arrow key moves the highlight to the next character. When finished, the patient presses the Ok key to update the care giver telephone number and return to the System screen. 
   The patient must then provide information regarding the Internet service provider (ISP) by selecting “ISP information.” Once selected, the Set ISP Information screen is displayed as shown in  FIG. 7 . The patient must set the telephone number, login, and password for the ISP that transfers the data to the server application. 
   When initially entered, the first character of the area code is highlighted. The + key and − key change the value of the currently highlighted field accordingly. The Right Arrow key moves the highlight to the next modifiable field. The patient presses the Ok key to update the ISP information and return to the System screen. 
   The patient may also view “system information” for base station  22  by selecting it on the System screen. When selected, the System Information screen is displayed as shown in  FIG. 8 . The System Information screen displays the firmware version, build number, and serial number of base station  22 . The patient presses the Ok key to return to the System screen. Base station  22  is ready once the updates are set. 
   The medication-taking and compliance data are viewable on base station  22 . When the Select Patient key is pressed on the Main Menu screen the Select Patient screen is displayed as shown in  FIG. 9 . System  10  can be used for a plurality of patients each taking a plurality of medications. When initially entered the first patient in the list is highlighted, and the patient presses the Up Arrow key and the Down Arrow key to move the highlight up and down the list, respectively. When the patient presses the Select key, the Patient Medication screen is displayed for the currently highlighted patient. The Main Menu key is pressed to return to the Main Menu screen. 
   The Patient Medication screen is shown in  FIG. 10 . The Patient Medication screen lists all the medications that the selected patient is taking. It also includes compliance data for each medication. The first medication in the list is initially highlighted, and the patient presses the Up Arrow key and Down Arrow key to move the highlight. When the patient presses the Select key, the Medication History screen is displayed for the selected medication. Pressing the Back key returns to the Select Patient screen. 
     FIG. 11  shows the Medication History screen, which lists all the dosages that have been taken and missed (compliance data). The first dose information is highlighted when the Medication History screen is initially entered, and the patient can press the Up Arrow and Down Arrow keys to move the highlight. When the Details key is pressed, the Medication Detail screen is displayed. The Back key displays the Patient Medication screen. 
   The Medication Detail screen is shown in  FIG. 12 . The Medication Detail screen lists all the medication-taking data and a summary of the compliance data. The Up Arrow and Down Arrow keys move the highlight up and down the list. The Back key displays the Medication History screen. With this and all the screens described for base station  22 , five minutes of inactivity results in the Main Menu screen being displayed. 
   Base station  22  is connected to network  30  by either modem  28   a  or interface  28   b , and base station  22  may be equipped with either or both. The physician can subsequently retrieve the compliance data whenever it is convenient to do so without having to wait for data from the patient or having to travel to the patient. Proprietary software allows the physician, care giver, etc., to view the information sent by base station  22 . The software is designed with the ability to generate custom reporting. In addition, the compliance data generated by the present invention is much more reliable than the patient&#39;s memory or relying on the patient to note compliance. 
     FIG. 13  shows dispenser  12  in more detail. Dispenser  12  includes container  18 , collar  16 , and cap  14 . Collar  16  further includes memory  48 , connector  56 , magnet  60   b , stationary base  90 , and pivoting base  92 . Cap  14  further includes connector  52 , IR transmitter  58   a , IR receiver  58   b , switch  60   a , battery  62 , audio indicator  64 , LED lamp  66   a , illuminated disc  66   b , board  94 , battery clip  96 , and top  98 . 
   Collar  16  attaches to container  18 . Memory  48  and connector  56  are mounted on pivoting base  92 . 
   Cap  14  attaches to collar  16 . Connector  52 , switch  60   a , LED lamp  66   a , and illuminated disc  66   b  are mounted on the underside of board  94 . IR transmitter  58   a  and IR receiver  58   b  are mounted on the topside of board  94  near battery  62  and audio indicator  64 . Microcontroller  44  (not shown) is also mounted on board  94 . Battery clip  96  holds battery  62 , or battery  62  may be mounted to board  94 . Top  98  covers the internal components of cap  14 . 
   In operation, container  18  is filled with medication, and collar  16  with cap  14  is attached adjacent the opening of container  18 . When it is time for the patient to take a dose of medication, LED lamp  66   a  is activated to illuminate illuminated disc  66   b , and/or audio indicator  64  is activated to notify the patient. The patient simply presses down on cap  14  such that pivoting base  92  pivots relative to stationary base  90  of collar  16  as shown in  FIG. 14 .  FIG. 14  shows shaded region  100 , which is the pivot range for opening dispenser  12 . Preferably, the pivot range is about 0.4 in. The patient dispenses a dose of medication and closes the portable cap assembly. 
   Switch  60   a  and magnet  60   b  form sensor  60  for sensing the opening/closing of dispenser  12 . Switch  60   a  is a dry reed switch. As pivoting base  92  pivots open, switch  60   a  changes state to generate an electrical signal by contacting magnet  60   b . When pivoting base  92  returns to its original position, switch  60   a  is no longer in contact with magnet  60   b , and the signal stops. Thus, microcontroller  54  automatically knows that the patient complied with the medication regimen without the patient having to remember to indicate that a dose was taken. 
   Top  98 , in the present embodiment, is transparent to allow for passage of IR signals. If another means of wireless communication is utilized, top  98  does not need to be transparent. Top  98  may also be equipped with a child proof lock mechanism. 
   The present invention is a device and system that reminds patients to comply with a medication-taking regimen. This is particularly helpful when many medications are being taken and/or when a patient tends to be forgetful. The present invention also allows the physician to track the patient&#39;s compliance without having to rely on the patient to do so, and the physician can obtain the compliance data from a remote location. 
   Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.