Apparatus for filling blister packs

Abstract

 The invention relates to an apparatus for filling blister packs with solid products. More especially the products to be distributed in blister packs are pharmaceutical dosage forms, e.g. tablets or capsules. The apparatus of the invention is particularly adapted for packaging drugs for use in clinical trials.

Description

[0001] The invention relates to an apparatus for filling blister packs with solid products. More especially the products to be distributed in blister packs are pharmaceutical dosage forms, e.g. tablets or capsules. The apparatus of the invention is particularly adapted for packaging drugs for use in clinical trials.

[0002] Blister packs for clinical trials are very frequently of large size and are composed of blisters set out in 1, 2 or more rows.

[0003] Clinical trials of pharmaceutical products are often performed at various dosages or in combination with other drugs. Accordingly, for the purpose of the trial, blister packs may be filled with drugs of various types and/or different dosages of the same drug. Most commonly, the packs may contain up to 4 different products which have to be administered to a patient in correct and specific order. Each kind of product is conveniently arranged in blisters marked with a corresponding sign and/or located in sequential order on the dispenser for ease of administration.

[0004] Accordingly, the distribution of the various drugs into blisters requires special care which cannot be met by standard industrial automation. Up to now, blister packs for clinical trials have been individually hand-filled, a procedure which is long and tedious and which is also subject to human error. Errors in filling packs for clinical trials are particularly serious, since if one or more patients receive an incorrect dosage regime, the entire trial could be invalidated.

[0005] It is also known to provide automated means for filling packs with solid objects, whereby an automated device, e.g. a robot arm, picks up a solid object from a storage area or delivery point, delivers it into the correct location in the pack, returns to pick up another solid object and repeats the process as often as necessary. Mechanical limitations (inertia of the arm) prevent such a "pick and place" process from being substantially faster and more accurate than a hand-filling operation.

[0006] The present invention avoids these problems by providing an apparatus for filling a blister pack with at least one type of dosage forms; each dosage form being distributed in pre-determined blisters on the blister pack.

[0007] Accordingly, the present invention provides an apparatus for filling blister packs comprising:

a) a holder means for the blister packs to be filled;

b) at least one dispensing unit for delivering dosage forms into the blister packs; and

c) a programmable unit to control the delivery of the dosage forms into the correct blisters.

[0008] In a preferred form, the apparatus comprises at least two, more preferably from two to four dispensing units. Also preferably, the dispensing units may be removable from the apparatus. In operation, the holder means retains the blister pack in a horizontal plane with the openings of the blisters uppermost, and a dispensing unit is positioned above the plane so that the dosage forms may fall into the blisters by gravity. Each dispensing unit is capable of dispersing one by one a large number of identical dosage forms.

[0009] The dispensing units are preferably moveable and each blister pack is immobilized while a dosage form is being delivered to it. Either the motion of all the dispensing units is co-ordinated and the blister pack remains fixed in one position during the entire filling operation; or the dispensing units move independently and the blister pack is fixed in one position while a first dosage form is being delivered to it from a first dispensing unit then is moved into a new position and remains in this new position while a second dosage form is being delivered to it from a second dispensing unit and simultane­ously the first dispensing unit fills a new blister pack with the first dosage form. This procedure may be continued for a third and fourth dosage form if necessary.

[0010] Alternatively, the dispensing units may be fixed whereas the holder means can be moved within the horizontal plane so that the blister pack can be displaced for filling each blister and for moving the blister pack from a dispensing unit to another one.

[0011] The holder means conveniently comprises a transporting mechanism, for example a conveyor belt, which brings empty blister packs in position to be filled and moves them away once they are filled. Advantageously this may also comprise means for securing the blister pack to the holder means so that it cannot be moved with respect to the holder means. In one embodiment, a conveyor belt comprises edge rails set at a distance corresponding to the dimensions of the blister pack. In another preferred embodiment, the holder means also comprises a rigid plate placed on and transported by a conveyor belt. The rigid plate is formed with a cavity designed to the dimensions of the blister pack so that the pack can be placed therein without clearance. At least one recess may be provided on at least one edge of the cavity to facilitate manual removal of the card.

[0012] The dispensing unit advantageously comprises a housing incorporating a storage cavity in which the dosage forms to be distributed are kept and a device for releasing the dosage forms one after the other, in co-operation with the storage cavity. This releasing device is suitably connected to electrical or electronic means so that the release of the dosage forms may be automatically effected.

[0013] Preferably the releasing device comprises a cylindrical or frustro-conical slotted rotor rotatably mounted within the housing and communicating both with the storage cavity and with a delivery port in the external wall of the housing. The slots in the rotor are dimensioned so that each slot can receive a single dosage form (e.g. one tablet or one capsule) and the rotor can rotate within the housing while one or more of the slots contains a dosage form. Preferably the rotor has at least two slots, the slots being spaced evenly around the perimeter of the rotor. Preferably the slots are arranged so that while one slot is open to the storage cavity, another slot is open to the delivery port. Where the dosage forms are elongated in shape, e.g. rectangular or ellipsoidal tablets or cylindrical capsules, then preferably the long axis of the corresponding slot is arranged so as to lie approximately parallel to the axis of rotation of the rotor.

[0014] In operation, the dispensing unit is arranged so that the axis of rotation of the rotor lies in a horizontal plane, the storage cavity is above the rotor and the delivery port lies below the rotor. A single dosage form is fed by gravity into an upper slot in the rotor, and, after one or more stepwise partial rotations of the rotor, is transported to the delivery port, where it is delivered by gravity into the specific blister of the blister pack which is positioned immediately below the delivery port.

[0015] The storage cavity advantageously comprises a bore in the housing in which the dosage forms are stacked, preferably communicating with a receptacle e.g. a tank where the dosage forms are stored in bulk. The bore may be detachably connected to the receptacle, for example by means of a flexible tube. The receptacle is preferably vibrated to assist the feed of dosage forms into the tube and thence into the storage cavity.

[0016] The dosage forms may be stacked in various ways; for example capsules of essentially cylindrical form may be stacked "side by side", i.e. with their long axes horizontal, or, preferably, "head to tail", with their long axes vertical. In the latter case, delivery of the dosage forms from the bore component of the storage cavity to the rotor slots may involve the direction of the bore changing along its length from vertical to near-horizontal, preferably terminating in a gently downward-sloping part communicating with a rotor slot via an opening in one of the end faces of the rotor. The rotor slot may then have its long axis closer to the axis of rotation of the rotor at its far end than at the end at which the dosage form enters the slot, so that the slot is essentially a prolongation of the bore.

[0017] Particular embodiments of the invention are described with reference to the attached figures.

Figure 1 shows a vertical cross-section of a dispensing unit.

Figure 2 shows an isometric view of a rotor for use in the dispensing unit of figure 1

Figure 3a is a side elevation and Figure 3b a plan view of a particular arrangement of four moveable dispensing units and their programmed motion.

Figure 4 is a plan view of a blister pack filling station and holder means.

[0018] With reference to Figures 1 and 2, the dispensing unit comprises an L-shaped housing (1) fixed to a moveable supporting bar (2) and provided with a delivery port (3) located in the base of the L.

[0019] The vertical part of the L contains a bore (4) for the supply of capsules, which is curved at its lower end to form a bend (5), fitting the angle of the L. The section of the bore (4) is such that the capsules introduced therein are stacked "head to tail" and are able to fall through the bend (5). At its upper end the bore is detachably connected by means of a flexible tube (6) to a container in which capsules are stored in bulk.

[0020] The horizontal part of the L is provided with a cylindrical cavity (7) to receive a cylindrical slotted rotor (0). The rotation axis (9) of the rotor is collinear with the axis of the horizontal part of the L. The rotor is engaged with a drive shaft (10) which is rotably mounted within the housing (1) and connected to a motor (11) external to the housing (1). In operation, the rotor communicates both with the bore (4) and with the delivery port (3). The end face (12) of the rotor adjacent to the bore (4) and to the drive shaft (10) is open whereas the other one is closed. The slots (13) of the rotor are dimensioned so that each slot can receive a single cylindrical capsule and the rotor can rotate within the housing while one or more slots contains a capsule. The slots are 4 in number and are spaced at regular intervals around the perimeter of the rotor. Each slot is arranged so that its long axis (14) is coplanar and substantially parallel with the axis of rotation (9) of the rotor but is closer to this axis at the closed end of the rotor than at its open end (12). In operation, the slot in the uppermost position is essentially a prolongation of the bore. Thus, a single capsule falls by gravity from the bore into the slot via the open end face of the rotor. Upon rotation of the rotor, the capsule is transferred opposite the delivery port (3) to be released while it is the turn of the other slots to be fed one by one.

[0021] The programmable unit (c) controls two separate operations. Firstly it controls the relative motion of the blister pack and the dispensing units so that, when a specific blister is to be filled, the correct dispensing unit is positioned directly above it. Secondly, it controls the operation of the dispensing units so that, when a specific dispensing unit is positioned directly above the correct blister, the dispensing unit is activated to deliver a single dosage form into that blister.

[0022] As stated, it is preferred that the dispensing units can move in two dimensions within a horizontal plane, above a blister pack immobilized in position to be filled. Optionally the dispensing units are fixed with respect to each other, and are moved as a single assembly.

[0023] In one preferred mode of operation, where there are for example four distinct dosage forms to be delivered into a blister pack having for example three rows of blisters, a single supporting bar (20) in Figure 3b supports four delivery units (21), (22), (23), (24), each with its own operating motor (25), (26), (27), (28), above the blister pack (29), to deliver dosage forms A, B, C and D respectively. The bar (20) may be moved by servo devices (not shown) in both the x and y directions, separately or simultaneously. In operation, the blister pack (29) is immobilised in the holder means (30), the first dispensing unit (21) is positioned above the blister at the end of the first row, and the entire dispensing unit assembly is moved in the x axis by means of the bar (20) from right to left along the first row of blisters, depositing dosage form A in the blisters for which it has been programmed. This motion will not be continuous, but rather stepwise, in units corresponding to the spacing between blisters or multiples thereof. When dispensing unit (21) reaches the end of the row, the entire assembly is moved along the y axis to the next row of blisters, then is moved from left to right along this row and finally from right to left along the third row, as shown by the solid line. By this time, all blisters requiring to be filled with dosage from A will have been filled, but none of the blisters requiring to be filled with B, C or D.

[0024] In the next stage of the operation, the assembly moves back from left to right along the third row while dispensing unit (22) fills any necessary blisters with dosage form B, then moves from right to left along the middle row and finally left to right along the first row, to return to its original position, dosage forms A and B having now been delivered. Two further cycles deliver forms C and D from (23) and (24), the filled blister pack is removed and a new empty pack put in its place, and the entire operation is repeated.

[0025] Short cuts may be taken whenever this will eliminate unnecessary movements and thereby save time. For instance, if in the above example no blisters to the left of blister (31) in the first row, and none to the left of blister (32) in the second row are required to be filled with dosage form (A), then on the first pass, the assembly could be moved directly from the position in which unit (21) is above blister (31) to that in which it is above blister (32), according to the dotted line.

[0026] Alternatively, it may be possible for more than one of the dispensing units to deliver dosage forms during a single pass of the assembly over a row of blisters.

[0027] In an alternative preferred mode of operation, there are a plurality of separate and independently moveable dispensing units. One embodiment of this is illustrated diagramatically in Figure 4, in which the blister pack filling station (33) has two such dispensing units (34). The pack filling station is surrounded by a conveyor belt (35) on which are transported several rigid plates (36) for carrying the blister packs. The relative position of the filling station and the belt is such that the dispensing units are operated just above the belt. Each rigid plate is initially in position (A) together with an empty blister pack and then is transported all along the belt to position (B1) where some blisters of the pack are filled with a first dosage form according to the programmed sequence of operation. Then the rigid plate is moved to position (B2) where the rest of the blisters are filled with a second dosage form. Meanwhile a second plate may be moved into position (B1) to have the selected blisters of its blister pack filled with the first dosage form. Finally the plate returns to position (A) so that the blister pack which is now completely filled can be sealed and replaced manually by a new empty one.

[0028] The programmable unit may be any conventional computer or microprocessor which is capable of storing in some form of memory device the correct sequence of operations (movements of the dispensing units or the blister pack as well as actuations of the dispensing units) to fill the blisters of the pack in the desired way, and of initiating these operations in the correct sequence by means of electronic signals switching on or off the electric current to the motors or solenoids which directly cause the operations. The entire sequence of operations may be individually programmed into the unit, but preferably the unit, when given only the layout of the blister pack (width and length, number of rows and columns and spacing of blisters) and the desired filling pattern, can itself calculate the optimum sequence of operations to bring about the desired result. The sequence of operations may also include the transportation of the blister pack to and from the dispensing units. Such a sequence may then be stored in the memory of the computer or microprocessor and accessed directly if the apparatus is required to carry out the identical filling pattern on a subsequent occasion. The memory may also be used to store the dimensions and layouts of a number of commonly used blister packs. Thus the changeover from one form of blister pack to another, for the same dosage forms, takes very little time.

[0029] The programmable unit may also regulate the speed at which the individual operations are carried out. While it is, of course, desirable that the cards be filled as quickly as possible, an upper limit to the speed of operation will be set by the need for the dosage forms to fall by gravity into the blisters, and by the mechanical limitations inherent in rapid intermittent motion. Too rapid filling may lead to dosage forms failing to fall correctly into the blisters. In practice, a time interval between successive deliveries from the same dispensing unit of approx. 200 ms is attainable.

[0030] A suitable microprocessor is the model ANC-32 supplied by Automelec S.A., Neuchatel, Switzerland.

[0031] In order to check during the filling operation that the operation is being carried out correctly, it is preferred that the programmable unit be associated with sensor devices capable of monitoring the filling operation. Such sensors may be electronic, gravimetric, or optical, the last of these being preferred. Conveniently, each dispensing unit may have mounted upon it two optical sensors. One, (15) in Figure 1, is directed at the blister below the delivery unit whereas the other one (16) is directed at the slot above the delivery port.

[0032] Each sensor comprises a fibre optic cable one half of the strands of which deliver light from a light source distant from the dispensing unit, and the other half of which are capable of transmitting reflected light back to a photoelectric cell, also distant from the dispensing unit. Thus if the sensor 15 or 16 is directed at a space occupied by a dosage form, light will be reflected from the dosage form and will give rise to a positive signal from the photoelectric cell, whereas if it is directed at an empty space, no light will be reflected and the photoelectric cell will give no signal.

[0033] During the filling operation, such a system may be used to ensure firstly, that a blister into which a dispensing unit is programmed to deliver a dosage form is in fact empty; secondly, that a dosage form is in place to be delivered, and finally, that the dosage form has cleared the rotor and has in fact filled the blister. If any of these is not the case, then the programmable unit may be programmed to stop the filling operation and give an alarm to the operator.

[0034] Although the apparatus has been described as useful for filling special blister packs for clinical trials, it may also be useful for short production runs of packs containing two or more different dosage forms; e.g. calendar packs or starter packs for products for which the optimum dosage must be built up to gradually.

Claims

1. An apparatus for filling blister packs comprising:

a) a holder means for the blister packs to be filled;

b) at least one dispensing unit for delivering dosage forms into the blister packs; and

c) a programmable unit to control the delivery of the dosage forms into the correct blisters.

2. An apparatus according to claim 1 which comprises at least two dispensing units.

3. An apparatus according to claim 1 or claim 2 in which the dispensing units are moveable and each blister pack is immobilized while a dosage form is being delivered to it.

4. An apparatus according to claim 3 in which each blister pack is immobilized during the entire filling operation.

5. An apparatus according to claim 3 which comprises at least two dispensing units and in which each blister pack in turn is immobilized in a first position while a first dosage form is being delivered to it and then is transported to a second position in which it is immobilized while a second dosage form is being delivered to it.

6. An apparatus according to any one of claims 1 to 5 in which the programmable unit controls (a) the relative motion of the blister pack and the dispensing units and (b) the operation of the dispensing units.

7. An apparatus according to any one of claims 1 to 6 in which the programmable unit is associated with sensor devices capable of monitoring the filling operation.

8. An apparatus according to any one of claims 1 to 7 in which the dispensing unit comprises a housing incorporating a storage cavity in which the dosage forms to be distributed are kept and a device for releasing the dosage forms one after the other, in co-operation with the storage cavity; said releasing device being connected to electrical or electronic means so that the release of the dosage forms be automatically effected.

9. An apparatus according to claim 8 in which the storage cavity comprises a bore in which the dosage forms are stacked head to tail; the bore being in co-operation with the releasing device.

10. An apparatus according to any one of claims 1 to 9 in which the holder means comprises a conveyor belt.

11. An apparatus according to claim 10 in which the holder means also comprises a rigid plate placed on and transportable by the conveyor belt.

12. A dispensing unit for delivering dosage forms into blister packs which comprises a housing incorporating a storage cavity in which the dosage forms to be delivered are kept and a device for releasing the dosage forms one after the other; said storage cavity comprising a bore in co-operation with the releasing device in which the dosage forms are stacked "head to tail".

13. A dispensing unit according to claim 11 in which the releasing device comprises a cylindrical or frustro-conical slotted rotor rotatably mounted within the housing and communicating both with the bore and with a delivery port in the external wall of the housing.

Drawing