Coating processes – Medical or dental purpose product; parts; subcombinations;... – Particulate or unit-dosage-article base
Reexamination Certificate
1999-03-23
2001-07-10
Beck, Shrive (Department: 1762)
Coating processes
Medical or dental purpose product; parts; subcombinations;...
Particulate or unit-dosage-article base
C427S294000, C118S423000, C118S500000, C118S503000, C053S900000
Reexamination Certificate
active
06258400
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a process and apparatus for the gelatin coating of medicaments.
BACKGROUND OF INVENTION
Many products, including prescription drugs, over the counter drugs (e.g., analgesics) and vitamins, come in a solid dosage (i.e., “medicament”) form. Two common shapes for these medicaments are referred to as “tablets” and “caplets”. Tablets are generally disc-shaped having a diameter that is greater than their height. Caplets are elongated shapes having a longitudinal axis that is greater than the greatest thickness of the medicament along the longitudinal axis, typically by approximately 2.5 times. Both usually include rounded ends and edges and a flat surface corresponding to the walls of the die in which the mixture of ingredients are pressed into the particular solid dosage form. The flat area is sometimes referred to as a sidewall and can form a corner or edge relative to the two sides on opposite sides of the sidewall.
A common problem with both caplets and tablets (collectively “medicaments”) is the texture or feel of their surfaces. Without any outer coating, both forms have a “chalky” texture formed by the compressed mixture. Research has established that some people believe uncoated medicaments are difficult to swallow. Research also has found, however, that people believe that medicaments having a gelatin or similar coating are significantly easier to swallow. Accordingly, many such processes have been developed and are known in the art.
One such process, disclosed in U.S. Pat. No. 599,865, utilizes a bar or plate which has been coated with a cleanly separable adhesive preparation, such as a combination of beeswax and rosin. Medicaments to be coated are pressed onto the adhesive and partially dipped into a coating mixture. The medicaments may then be dried and pressed onto a second adhesive coated bar or plate so that the remaining portions of the medicaments may be dipped.
U.S. Pat. No. 540,538 discloses a machine for dipping medicaments which utilizes a plate having countersunk holes to retain tablets by the application of a vacuum through the holes. The plate is placed over a vacuum box and medicaments are placed in each hole. A vacuum is then applied and the box and plate are inverted, thereby allowing the medicaments to be dipped in a coating bath. Once the medicaments have been dipped, the box is returned to its upright position, the vacuum is removed and the plate is manually removed, with the medicaments in place, to allow drying of the coating. After drying, the medicaments may be transferred onto a second plate with their uncoated sides exposed by manually placing the second plate over the medicaments contained on the first plate and flipping the two plates over. The uncoated sides may then be coated as described above.
Another process, disclosed in Japanese Patent Publication No. 41-13997, utilizes rigid tubes to retain tablets on their ends by the application of a suction force through the tube center. After dipping the tablets to approximately their midpoints and drying, the tablets are inverted and transferred onto opposing tubes. The vacuum is then switched from the first set of tubes to the second thereby exposing the uncoated portions of the tablets to be dipped. A drawback of this system is that no means is provided to easily center the tablets on the tubes.
U.S. Pat. No. 2,373,721 refers to a system for coating medicaments in which the medicaments are held over a coating tank in an inverted orientation by suction tubes. Cups slightly larger than the individual medicaments are then raised from an initial position, submerged in the coating, to immerse the individual medicaments in coating material contained within the cups.
U.S. Pat. No. 4,965,089 refers to the use of a caplet holding plate having sets of caplet gripping collets on both sides thereof. Caplets, initially disposed on one side of the plate, are dipped in a gelatin coating on one end then pushed through the plate so that the other side of the caplet may be coated. The disadvantages of such a system are that the caplet holding plate is not suitable for coating tablets having a height substantially less than their diameter. In addition, the coated surface may be damaged when pushed through the collet to the other side of the caplet holding plate.
U.S. Pat. No. 5,228,916, refers to the use of moveable vacuum tubes, which extend through a carrier plate, to secure tablets to be dipped. Such a process is not, however, well suited for coating caplets whose ends may not be readily secured to a vacuum tube. In addition, the use of multiple moveable vacuum tubes makes it difficult to maintain the tablets centered on the vacuum tubes in a level plane parallel with the surface of the coating in which the tablet is to be dipped. It is, therefore, difficult to obtain a level transition line when coating tablets with more than one color coating.
Therefore, there exists a need for a medicament coating system which may be easily adapted to coat medicaments of different sizes and shapes and which produces a uniform coating with no damage to the finished product.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method and apparatus for coating medicaments to produce a uniform, undamaged coating.
A further object of the present invention is to provide a method and apparatus for coating medicaments which may be easily adapted to coat medicaments of different sizes and shapes.
Still another object of the present invention is to provide an apparatus to secure medicaments to a pallet in a level orientation such that the pallet may be inverted and the medicaments dipped in a coating mixture.
Yet another object of the present invention is to provide a method and apparatus to evenly and quickly dry a coating once it has been applied to a medicament.
The above and other objects are achieved in accordance with a first aspect of the present invention by an apparatus comprising a continuous conveyer system to advance a plurality of pallets through the sequence of stations at which the steps necessary to dip and coat each side of a medicament with a coating are performed. The stations of the system include a loading station, at least one dipping station, at least one dryer station, a reorientation station and an unloading station.
Medicaments to be coated are loaded into pallets with a first portion of the medicaments exposed at the loading station. The pallets are oriented in an upright position so that the medicaments extend above the surface of the pallet. After a pallet is loaded, it proceeds along the conveyer to the first dipping station. At the first dipping station, a vacuum is applied to the pallet to secure the medicaments to the pallet and the pallet to the end effector tooling of a robot arm. The pallet is then inverted and the first exposed portion of each of the medicaments is dipped into a bath to coat the exposed end. The dipping step has a first dipping profile of insertion rate and depth, dwell time in the bath, and removal rate to control the coating on the medicament. Preferably, the bath is a gelatin or a gelatinous bath for gel coating the medicament.
After the dipping step, the pallet is returned to its upright position on the conveyer, and the vacuum is removed. The pallet is then advanced to the dryer station, where the coating is dried. The dryer station includes a series of conveyors similar to those which transport the pallets between the different stations. The dryer conveyors transport the pallets through at least one, and preferably two drying rooms. The drying rooms have a controlled environment and vertical air flow plenums over each conveyor section. The air plenums are disposed horizontally over the path of the pallets and include rows of air directing apertures, preferably in a sinusoidal arrangement, running in the direction of product flow for directing a flow of air onto the medicaments. When the pallets exit the dryer station, the coating on the first exposed portion of the medicaments has bee
Brehant Jeffrey D.
Hoover Linn C.
Kucharski Thomas
Reiter Thomas C.
Revelle David J.
Bayer Corporation
Beck Shrive
Kolb Jennifer
Orrick Herrington & Sutcliffe LLP
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