Patent Publication Number: US-2005121102-A1

Title: Capsule filling device and method of operation

Description:
FIELD OF THE INVENTION  
      This invention relates in general to capsule filing devices, and more particularly to mechanical capsule filling devices adapted to fill small quantities of capsules, such as a single prescription, with the exact kinds and amounts of medications required to meet the needs of one particular patient.  
     BACKGROUND OF THE INVENTION  
      Medicines and pharmaceutical substances are generally manufactured in tablet or capsule form in pre-determined dosages chosen from a relatively limited range, based on the presumptions of the manufacturer as to what dosages are likely to be prescribed by physicians for a majority of their patients. Without a flexible range of doses being available, the patient is forced to break tablets in half, or to remember complicated dosing schedules, such as having to take two tablets on Mondays, Wednesdays and Fridays, and three tablets on all other days of the week. Because each patient is different, such pre-determined dosages are almost invariably an approximation or a compromise relative for what the patient actually needs.  
      For example, certain psychotropic medications such as lithium carbonate (used to treat bipolar illness) are safe and effective only within a relatively narrow range of dosages based on a variety of factors including the patient&#39;s age, body weight, drug elimination rate, general health, and tolerance to the particular medication prescribed. If the dosage is too low, as reflected by the concentration of the medication in the patient&#39;s blood, its threshold of effectiveness may not have been reached and the patient will enjoy no benefits. On the other hand, if the dosage is too high, while the patient may be relieved of his or her symptoms, serious symptoms of toxicity or other intolerance to the medication may result.  
      Other situations in which a variable, continuously adjustable dose would be of benefit to both the prescribing physician and the patient include dosage adjustment based on serum or plasma concentration of drugs having a relatively narrow therapeutic window, such as (for example) theophylline, digoxin, and many anticonvulsants, including phenobarbital and dilantin, as well as drugs with a variable and unpredictable patient response such as the immunosuppressants methotrexate, prednisone and cyclosporine.  
      The invention is of particular benefit to the practice of veterinary medicine, in which the physician encounters wide extremes of size and species. It also benefits research pharmacists who are required to prepare small batches of capsules with various fillers for purposes of stability testing, analytical assay, reference material, clinical trials and dissolution studies.  
      For these reasons it would be highly advantageous if the prescribing physician could be able to prescribe medications in filled capsules which are individually tailored to the needs of each patient in terms of both type of medication (including combinations of drugs) and dosage. For this purpose, the present invention provides a capsule filling device capable of filling capsules with any filler material, particularly dry flowable powdered or micro-encapsulated medication in any dosage desired. In addition, it allows for filling individual groups of capsules with specific doses of one or more medications.  
      The prior art includes a variety of capsule filling devices and methods of operation which accomplish the task of measuring and distributing dry flowable medications into individual capsules. One example is U.S. Pat. No. 5,797,248 which discloses a manual capsule filling device in which a known quantity of dry material, such as from a bottle in which the weight of the contents is known, is emptied into a reservoir which overlies a rotary dosage plate containing a plurality of spaced cavities, each cavity being of a known volume. The medication is allowed to flow into and fill the cavities, whereupon the dosage plate is rotated to transfer its contents into individual capsules below. The capsules are then capped and replaced by empty capsules, and the operation is repeated as many times as is necessary to fill the required number of capsules. However, this system has several disadvantages, such as the inability to fill capsules by weight instead of volume, and the inability to change the dosage without emptying the device and changing the dosage plate.  
      Another manual capsule filling device is shown in U.S. Pat. No. 5,660,029 in which empty capsules are placed in cavities in a funnel-shaped tray. A known quantity of medication is placed in the tray and raked or swept into the capsule, such as by tilting or tapping the tray, after which the capsule contents are compressed by tamping before the capsule is capped. The tamping tool is also useable to remove the filled capsules from their cavities.  
      Mentioned in U.S. Pat. No. 5,797,248 are other examples of similar prior art. Canadian Patent 494,695 shows a capsule filling device in which a measured amount of pharmaceutical is placed on a spreader plate with wells, the depth of the wells being adjustable. The pharmaceutical is spread into the wells until it is flush with the tops of the wells, the spreader plate is covered with a funnel system and turned upside down to allow the dry medication to funnel into the capsules. U.S. Pat. No. 5,321,932 shows a device to open and close capsules so that they may be filled, however, the method of filling the capsules is not described. U.S. Pat. No. 4,619,336 provides a method and apparatus for weighing doses of powder in which powder is fed onto a weigh scale which stops the powder flow just below the desired weight, at which point remaining powder is allowed to run into the weighing receptacle.  
      Highly mechanized devices for filling capsules in mass production are also shown in the prior art, such as U.S. Pat. Nos. 6,170,226, 5,490,702, 5,018,335 and 4,964,262, and 4,731,979, but all of these machines lack the flexibility and adaptability of the present invention because they depend on a mechanical or pneumatic charging system which must be re-set, re-calibrated and re-tested every time a new and different batch of capsules is run.  
     SUMMARY OF THE INVENTION  
      A principal object of the present invention is to provide an improved capsule filling device which is easily and quickly adaptable to filling small batches of capsules with predetermined quantities of medication intended to fill the needs of a specific patient and prescription. A related objective is to replace the tedious and laborious task of hand measuring and filling each batch of capsules, with its resultant inconsistencies and opportunities for error, with a small scale but relatively high speed process which is adaptable to computer monitoring and control, and which permits the creation and retention of a detailed record of each batch of capsules processed.  
      Another object is to provide a capsule filling device and method of operation in which a measured quantity of medication is distributed evenly by centrifugal force from any suitable power means, such as an electric motor, into a predetermined number of capsules, so that the total amount of medication supplied to the group of capsules as a whole is accurately known, with little or no waste. This allows a pharmacist to easily fill prescriptions on an individual basis, with a consequent decrease in inventory, and reduction of dispensing errors. The reduction in inventory will help insure that the dispensed pharmaceuticals are always “fresh”. Tailor-made or “custom” prescriptions containing two or more pharmaceuticals in combination can be easily dispensed in controlled batches.  
      A related object is to provide a capsule filling device with a minimum of moving parts, all of which may be conveniently removed for cleaning or sterilizing. Thus the device can be quickly and easily prepared for filling the next batch of capsules with a different medication, or with a different dosage, to suit the individual needs of a different patient. A further related object is to provide means for quickly and positively ejecting filled and covered capsules from the device by power means, such as compressed gas.  
      Another principal object is to provide a powered capsule filling device having an electronic control system for controlling, monitoring, and recording each batch of filler material and associated capsules, whereby a detailed record is created automatically to confirm and verify the filling of each such batch. By controlling and monitoring the filling of each batch of capsules by electronic means, the processing of each batch will leave behind an “audit trail” for the protection of the physician and the pharmacist as well as the patient. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      A detailed description of two embodiments are provided herein below with reference to the following drawings, in which:  
       FIG. 1  is a partial sectional perspective view of a first preferred embodiment of the capsule filling device of the present;  
       FIG. 2  is a partial sectional elevation of the first embodiment of  FIG. 1 ;  
       FIG. 3  is a fragmentary view of an alternative construction of the embodiment of  FIG. 1 ;  
       FIG. 4  is an enlarged partial sectional perspective view of the device of  FIG. 1 , particularly illustrating the peripheral capsule receptacles, impeller plate and radial guide ribs;  
       FIG. 5  is an enlarged partial sectional elevation of an alternative construction of the capsule holders of the embodiment of  FIG. 1 ;  
       FIG. 6  is a detail sectional elevation showing an alternative construction of the first embodiment of  FIG. 1 , and further showing the path of a dry flowable material being distributed into a receiving capsule;  
       FIG. 7  is a detail sectional perspective of the device of  FIG. 1  showing the spatial arrangement of the inner cover, distribution drum, peripheral collection surface, collection pockets and capsule holders;  
       FIG. 8  is a partial sectional elevation of a second embodiment of the invention having an impeller plate which is independently rotatable relative to the distribution drum; and  
       FIG. 9  is a block schematic diagram showing the general relationships of a computer-controlled operating system for the device of the present invention. 
    
    
      In the drawings, the two embodiments of the invention are illustrated by way of example. It must be understood that the description and drawings are only for the purpose of illustration and as an aid to understanding, and are not intended as a definition of the limits of the invention.  
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Two preferred embodiments of the present invention are described. While both incorporate all of the major features of the invention, they differ in their internal construction, particularly as regards to means by which the unfilled capsules are held and retained by the rotating elements of the device.  
      Referring to the first preferred embodiment of  FIGS. 1 and 2  , there is shown a device for filling empty medicine capsules comprising a base  10  supporting an enclosure  11  within which is located a central shaft  12  driven by a power means  13 , which in the illustrated embodiment is a variable speed electric motor. The power means  13  may also be a compressed air motor, or a spring-wound mechanism, or a hand crank, or a shaft driven by a separate power unit (not shown).  
      Atop the enclosure  11  is a removable upper cover  14  having at its center, in line with the central shaft  12 , an inlet opening  15  through which any dry flowable material, such as a medicine or pharmaceutical, may be introduced.  
      Within the enclosure  11  is a rotating assembly consisting of a capsule holder disk  16  removably affixed to the central shaft  12  by a key means  17 , or other suitable means, for rotation by the power means  13 . The capsule holder disk  16  contains a plurality of spaced hollow capsule holders  18 , preferably but not necessarily evenly spaced around its periphery, with each holder  18  adapted to hold an unfilled capsule element  19 . Above the capsule holder disk  16  is a distribution drum  20 , concentric with the central shaft  12  and inlet opening  15 , and having an upper face serving as an impeller plate  21 . This plate  21  is positioned to receive material introduced through the removable upper cover  14  through a funnel-shaped receptacle  22  which directs the material onto an impact point  23  at the center of the impeller plate  21 . The distribution drum  20  is covered by a lid  24  having an opening concentric with the funnel receptacle  22 .  
      Preferably, the drum  20  is made of inexpensive lightweight injection-molded or blow-molded plastic material, to reduce expense. In practice, it is desirable to produce the drum  20  so inexpensively that it may be disposed of after a single use, to eliminate the need for washing and sterilization, and to prevent cross-contamination of the capsules being filled.  
      When the impeller plate  21  rotates, the material introduced through the funnel receptacle  22  is thrown outward by centrifugal force against a peripheral collection surface  25  at the inner periphery of the distribution drum  20 . The peripheral collection surface  25  is shaped with an upwardly-extending side wall to collect and retain material flung against it by centrifugal force as the distribution drum  20  is rotated by the power means  13 .  
      Incorporated into the distribution drum  20  beneath the peripheral collection surface  25  are individual collection pockets  26 , each of which terminates in a funnel-shaped discharge opening immediately above an unfilled capsule  19  element held in a holder  18  of the capsule holder disk  16 .  
      The upper surface of the impeller plate  21  may optionally include a plurality of evenly spaced upstanding radial guide ribs  27  for urging the flowable material outwards under centrifugal force, with the conical upper surface of the drum  20  serving as a flow splitter, dividing the flowing stream of incoming material and forcing it to be distributed in a relatively uniform manner as it is directed by centrifugal force against the peripheral collection surface  25 . The peripheral collection surface may optionally have grooves, rigs, indentations or roughened surfaces to prevent filler material from migrating from the impact point.  
      In use, the invention of the first embodiment ( FIG. 1 ) is utilized by first removing the upper cover  14  and lifting the distribution drum  20  and lid  24  from the shaft  12  to expose the holders  18  in the capsule holder disk  16 . An individual unfilled capsule  19  is placed in each holder  18 . The distribution drum  20  and lid  24  and upper cover  14  is replaced and the power means  13  energized to start the rotatable assembly (shaft  12  and capsule holder disk  16  and distribution drum  20  and lid  24 ) rotating.  
      When the assembly has reached a rotational speed sufficient to adequately and evenly distribute the filler material, a measured quantity of dry flowable pharmaceutical or other material is introduced into the screened opening of the inlet funnel  22 . The filter screen  29  prevents clumps of material from dropping onto the impeller plate  21 . The material flows by gravity onto the impact point  23  of the impeller plate where it is flung by centrifugal force (and assisted by the radial guide ribs  27  if used) against the peripheral collection surface  25  in a substantially even circumferential distribution.  
      At that point, when substantially all of the measured quantity of material has been introduced and distributed evenly about the collection surface  25 , the power means  13  is de-energized and the rotational assembly is allowed to slow and stop. As it does so, the centrifugal forces of rotation are overcome by the forces of gravity, and the material commences to flow, slowly and evenly, out of the collection pockets  26  and through the funnel-shaped collection pockets  26  into the empty capsules  19 , thus assuring that each capsule is filled with substantially the same amount of material.  
      After the filler material has been completely distributed into the capsules  19  in the manner described above, the cover  14  and lid  24  and distribution drum  20  are removed. At this point the operator may place closures (not shown) on the filled capsules.  
      To aid in holding the capsules  19  in their holders  18 , and in ejecting them after they are filled, a channel  28  is provided in the base of each capsule holder  18 . A vacuum source (not shown) may be connected to the channel  28  to draw the unfilled capsules firmly into the capsule holder disk  16 . After the filling process is completed and the capsules are closed, the channel  28  may either be subject to positive gas pressure or a blunt ejector pin ( FIG. 5 ) may be passed upward through the channel  28  to serve as an ejection means to eject the filled capsules.  
      An alternative version of this first embodiment is shown in  FIGS. 6, 7  and  8   2 , where the distribution drum and capsule holder disk and capsule holders are incorporated in a single unit.  
      A second embodiment of the invention is shown in  FIG. 8 , in which the distribution drum  20   a  is physically separate from the impeller plate  22   a , and driven through a separate inner concentric drive shaft  12   a  which is separately rotatable with respect to the outer drive shaft  12   b , and can be driven by the power means  13   a  through a selectable ratio transmission means (not shown). This permits the impeller plate to be driven faster, slower, or at the same speed relative to the distribution drum, or (if desired) in a different direction. By this means the device is able to fill capsules with a wider range of sizes and weights of particle sizes.  
      Ideally, the device of the present invention may be combined with a microprocessor controller or central processing unit  30  ( FIG. 9 ), with which are associated various data input and output means such as a keyboards and/or mouse  31 , barcode reader  32 , digital weigh scale  33 , capsule counter  34 , drum speed and position sensor  35 , safety interlocks  36  (to prevent opening during rotation), motor speed and position control  37 , a memory unit  38  (to store individual formulation recipes), a network interface  39  (for remote operation), a capsule eject mechanism  40  (associated with an ejection means as previously described), a visual display  41 , an audible alert  42  (to signal malfunctions) and a printer  43  for making a hard-copy record of the capsule filling process.  
      In use, prescription information is received via the various data input means and recognized and recorded by the central processing unit  30 . The operator takes note of the information and gathers together the required number of capsules and amount of filler material (or materials) with which to fill the capsules. For verification, the controller may require the operator to scan bottle labels and/or weigh out the prescribed amount of material on a recording scale (not shown), all of which information is recorded by the controller  30  in association with this particular batch of capsules. The controller then permits the operator to energize the power means  13  and fill the capsules, after which it causes a suitable label for the batch of medication to be created by the printer  42 .  
      According to the invention, and as a substantial advantage over the prior art, the emptying of a measured quantity of pharmaceutical material into a predetermined quantity of unfilled capsules insures that the total quantity of medication supplied by that batch of capsules, in response to a single prescription, is in the aggregate exactly the amount specified for that patient for that number of doses and inadvertent double filling of capsules is prevented.  
      In addition, and as a further advantage of the invention, the filler material for the capsules need not be of a single medication, but can be a combination of various medications in predetermined proportions, to insure that the patient gets exactly the mix of pharmaceuticals prescribed by his or her physician, and without risk that by missing one pill or another the therapeutic mixture of medications will be inadvertently upset or skewed.  
      Other variations and modifications of the invention are possible. All such modifications or variations are believed to be within the sphere and scope of the invention as defined by the claims appended hereto.  
     Reference Numerals  
     
         
           10 . Base  
           11 . Enclosure  
           12 . Central shaft  
           13 . Power means  
           14 . Upper cover  
           15 . Inlet opening  
           16 . Capsule holder disk  
           17 . Key means  
           18 . Spaced capsule holders  
           19 . Unfilled capsule element  
           20 . Distribution drum  
           21 . Impeller plate  
           22 . Funnel receptacle  
           23 . Impact point  
           24 . Lid  
           25 . Peripheral collection surface  
           26 . Collection pocket  
           27 . Radial guide ribs  
           28 . Channel  
           29 . (not used)  
           30 . CPU  
           31 . Keyboard/mouse  
           32 . Barcode reader  
           33 . Digital weigh scale  
           34 . Capsule counter  
           35 . Drum speed and position sensor  
           36 . Safety interlocks  
           37 . Motor speed and position control  
           38 . Memory unit  
           39 . Network interface  
           40 . Capsule eject mechanism  
           41 . Visual display  
           42 . Audible alert  
           43 . Printer