The use of hard gelatin capsules for the containment of pharmaceuticals in unit dosage forms has been known for years. As opposed to tablets wherein the medicament is itself compressed into an ovoid or elliptical cylinder and swallowed directly, solid gelatin capsules have been used to administer pharmaceuticals in many different forms such as powders, liquids, oils and the like. As opposed to tablets, capsules completely envelop the drug until it reaches the stomach wherein the gelatin coating is eventually dissolved thereby releasing the medicament for absorption into the bloodstream. This provides an additional benefit of not only taste-masking many otherwise bitter tasting or unpalatable pharmaceuticals but also provides a lubricious mouth-feel or texture to the surface of the medicament for easier swallowing and passage into the digestive system.
Standard capsules known in the art are prepared by dipping rows of stainless steel pins into solutions of gelatin, starch gelatin or gelatin glycerin. The pins are removed from solution, the dipped portion dried and stripped off the pin. Both capsule halves are formed in this manner. One half is generally referred to as the capsule "body" while the half that fits over the open end of the first is referred to as the "cap". The cap is mated with the body by fitting over its open end. The capsules are generally sold in this assembled manner and the drug or medicament filled later. Commercially available capsule making machines are manufactured by Cherry-Burrell, Cedar Rapids, Iowa 52406 for example.
A drawback in the use of hard gelatin capsules become frighteningly evident several years ago when several people died taking a well known, over-the-counter analgesic that had been laced with cyanide through tampering. The problem that exists in standard capsule technology of the art is that the two halves of a gelatin capsule can be pulled apart and the medicament exposed. Anything can be added or detracted from the composition at this point and the halves then compressed together to again form one whole capsule. Moreover, there is nothing that would indicate the composition inside the gelatin capsule had been changed so as to serve as a warning to any unsuspecting patient or consumer, i.e. there is no tamper-evident indication incorporated into most commercially available gelatin capsules.
The cyanide tampering incidents forced many if not all prescription and over-the-counter pharmaceutical manufacturers to take additional packaging steps to insure that such tampering could not occur without it at least being noticed by the otherwise unsuspecting patient prior to a possibly fatal consumption. "Blister packs", safety sealed bottles and other forms of safety packaging rapidly appeared throughout the pharmaceutical industry in an effort to prevent any further tampering. Capsule products were withdrawn from the market altogether and in some cases were replaced by "caplets", solid oblong tablets comprised of the medicament and coated with a material such as cellulose, pectin, etc. The solid form of the drug not only protected against further tampering since the caplet would have to be broken apart in order to incorporate any additional ingredients and this lack of caplet integrity is easily discernible, but the coating also provides an ease in swallowing and protected some medicaments such as aspirin from causing stomach distress.
However, all of these reactionary measures and their precautions have added additional expense to the manufacture and packaging of both prescription and over-the-counter drugs. U.S. Pat. No. 4,820,524 to Berta points out that beyond the additional cost factors of these precautions, consumer surveys suggest that the shiny, familiar capsule shape has a special appeal to patients as being easy to swallow. It is additionally theorized that consumers perceive capsuled medicaments as being more effective in light of the long term association of the capsule with many well known and well respected pharmaceutical companies and their products. This could possibly add an additional placebo factor to their actual effectiveness. There exists then, a very real need for truly tamper-resistant capsule or capsule-like encapsulating materials as carriers for pharmaceuticals and other medicaments.
A number of references have coated pills or tablets by dipping them into gelatin solutions of one type or another. U.S. Pat. No. 599,865 to Richards discloses an apparatus for coating pills with gelatin whereby a bar is coated with an adhesive which holds the pills to be coated in place. The bar is then fitted over a second plate containing holes to which the affixed pills are aligned. The bar and plate, once joined, immerse half of the pill body into the gelatin. The bar and plate are then inverted whereby the other half is coated. Whereas the process may coat the pills with a material such as cellulose, starch, etc., there is no indication that a capsule-like appearance is achieved. Moreover, the process must be carried out manually and in no way could meet the production demands of today's world.
Of particular interest is U.S. Pat. No. 4,820,520 to Berta wherein a solid medicament core such as a caplet is provided with a capsule-like coating by dipping first one end of the capsule into a gelatinous solution so as to cover one-half of the caplet. This is then dried and the other end is dipped into the solution so that both gelatinous "dips" over-lap at approximately the midway point of the longitudinal axis of the caplet. This over-lapping of the gelatin coats is perceived as the seam created when two solid gelatin capsule halves are joined in the traditional procedure known in the art. U.S. Pat. No. 4,867,983 also to Berta discloses the method whereby the caplet is coated with a first gelatinous core on one end followed by the coating of a second gelatinous core on the other end which is thicker than the first so as to simulate the interlocking halves of a hollow gelatin capsule. The dipping procedure however, must be precise and requires intricate processing and mechanical steps in order to guarantee a smooth gel coating about the caplet. Since two dipping steps are required, the likelihood of uneven coating about the caplet remains high and many caplets are not assured of consistency in capsule shape and size.
It is an object of the present invention to provide a tamper-resistant pharmaceutical capsule whereby a medicament in the form of a caplet, is encapsulated with a solid gelatin capsule which is essentially tasteless and easy to swallow.
It is a further object of the present invention to provide a method for encapsulating a medicament in the form of a caplet with a solid gelatin capsule by shrinking said capsule about said caplet with no space therebetween.
It is yet a further object of the present invention to provide a capsule-like medicament wherein two solid gelatin capsule halves are fused about the caplet and cannot be removed without substantial damage thereto.
It is yet a further object of the present invention to provide a method for the preparation of a tamper-resistant capsule about a solid medicament in the form of a caplet by shrinking said capsule at a specific temperature and relative humidity so as to insure uniform shrinkage and fusion of said capsule about said caplet.