Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Tablets – lozenges – or pills
Reexamination Certificate
2000-02-11
2001-08-21
Spear, James M. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Tablets, lozenges, or pills
C424S482000, C424S479000, C424S480000, C424S481000, C514S777000, C514S772300, C514S786000, C514S782000, C514S781000
Reexamination Certificate
active
06277409
ABSTRACT:
The present invention relates to a protective coating for soft tablets comprising at east 50 weight percent of a thermoplastic material having a melting point of less than bout 120° C.
BACKGROUND OF THE INVENTION
Pharmaceuticals intended for oral administration are typically provided in solid form as tablets, capsules, pills, lozenges, or granules. Tablets are swallowed whole, chewed in the mouth, or dissolved sublingually. Soft tablets that either are chewed or dissolve in the mouth are often employed in the administration of pharmaceuticals where it is impractical to provide a tablet for swallowing whole. With chewable tablets, the act of chewing helps to break up the tablet particles as the tablet disintegrates and may increase the rate of absorption by the digestive tract. Soft tablets are also advantageous where it is desirable to make an active ingredient available topically in the mouth or throat for both local effects or systemic absorption. Soft tablets are also utilized to improve drug administration in pediatric and geriatric patients. Soft tablets designed to disintegrate in the mouth prior to swallowing are particularly useful for improving compliance of pediatric patients.
Generally, soft tablets are made by direct compaction of a mixture of tabulating compounds including an active ingredient, flavoring, binders, etc. The mixture is fed into a die cavity of a tablet press and a tablet is formed by applying pressure. Hardness of the resulting tablet is a direct function of the compaction pressure employed and the compatibility of the ingredients in the formulation. A softer tablet, having an easier bite-through, may be prepared by employing reduced compaction pressures. The resulting tablet is softer, but also more fragile, brittle, and easily chipped.
Soft tablets designed to disintegrate in the mouth without chewing are disclosed by Cousin et al., in U.S. Pat. No. 5,464,632, and Wehling et al., in U.S. Pat. Nos. 5,223,264 and 5,178,878. While these soft tablets for oral administration advantageously disintegrate completely in the mouth prior to swallowing, they have the disadvantage of being highly friable, requiring costly specialized handling and packaging in order to prevent breakage.
It is known to apply outer coatings to a chewable tablet in order to protect the soft core. Typically, such outer coatings contain cellulose derivatives as major ingredients, which have relatively high melting points, i.e., greater than 135° C. For example, PCT Application No. WO 93/13758 discloses the application of a thin layer of coating material such as a disaccharide, polysaccharide, or cellulose derivative onto a compressed tablet. U.S. Pat. No. 4,828,845 relates to the coating of a comestible with a coating solution comprising xylitol, a film-forming agent such as methyl cellulose, a binder, optionally a filler, and optionally a plasticizer such as polyethylene glycol, the balance of the solution being water. The plasticizer makes up only about 3 to 7 weight percent of the coating solution disclosed in the '845 patent. U.S. Pat. No. 4,327,076 discloses a compressed, soft, chewable tablet containing an antacid or other active ingredient that may be coated with a sealant or a spray coat of chocolate.
It has now been discovered that a soft tablet having a hardness of up to about 15 kp/cm
2
may be coated with a molten composition comprising at least 50 weight percent of a thermoplastic material having a melting point of less than about 120° C. The molten composition is solidified into a protective coating, and the coated tablet may, if desired, be further coated with one or more outer coatings made of conventional coating materials, such as saccharides, cellulose derivatives, and the like. Application of the protective coating according to the invention stabilizes the friability of the tablet. It also provides a water-resistant barrier for the tablet core. This is especially advantageous when its is desired to use conventional outer coatings on the tablet, which can erode the tablet core. By application of such outer coatings over the protective coating, the integrity of the tablet core is preserved.
SUMMARY OF THE INVENTION
The invention provides a process for coating a tablet having a hardness of up to about 15 kp/cm
2
, comprising: a) applying a molten composition to the tablet, said molten composition comprising at least 50 weight percent of a thermoplastic material having a melting point of less than about 120° C.; and b) solidifying said molten composition into a protective coating, as well as a tablet coated by this process. The invention also provides a coated tablet comprising a core having a hardness of up to about 15 kp/cm
2
and comprising at least one active ingredient, and a protective coating comprising at least 50 weight percent of a thermoplastic material having a melting point of less than about 120° C. disposed over said core.
DETAILED DESCRIPTION OF THE INVENTION
The tablet core comprises at least one active ingredient. Suitable active ingredients include pharmaceuticals, minerals, vitamins and other nutraccuticals. Suitable pharmaceuticals include analgesics, decongestants, expectorants, antitussives, antihistamines, gastrointestinal agents, diuretics, bronchodilators, sleep-inducing agents and mixtures thereof. Preferred pharmaceuticals for use as the active ingredient include acetaminophen, ibuprofen, flurbiprofen, naproxen, diclofenac, aspirin, pseudoephedrine, phenylpropanolamine, chlorpheniramine maleate, dextromethorphan, diphenhydraminc, famotidine, loperamide, ranitidine, cimetidine, astemizole, terfenadinc, fexofenadine, cetirizine, antacids, mixtures thereof and pharmaceutically acceptable salts thereof. More preferably, the active ingredient is selected from the group consisting of acetaminophen, ibuprofen, pseudocphedrine, dextromethorphan, diphenhydramine, chlorpheniramine, calcium carbonate, magnesium hydroxide, magnesium carbonate, magnesium oxide, aluminum hydroxide, mixtures thereof, and pharmaceutically acceptable salts thereof.
The active ingredient(s) are present in the tablet in a therapeutically effective amount, which is an amount that produces the desired therapeutic response upon oral administration and can be readily determined by one skilled in the art. In determining such amounts, the particular compound being administered, the bioavailability characteristics of the active ingredient, the dose regime, the age and weight of the patient, and other factors must be considered.
If the active ingredient has an objectionable taste, it may be coated with a taste masking coating, as known in the art. Examples of suitable taste masking coatings are described in U.S. Pat. No. 4,851,226, U.S. Pat. No. 5,075,114, and U.S. Pat. No. 5,489,436. Commercially available taste masked active ingredients may also be employed. For example, acetaminophen particles which are encapsulated with ethylcellulose or other polymers by a coaccervation process may be used in the present invention. Coaccervation-encapsulated acctaminophen may be purchased commercially from Eurand America, Inc. Vandalia, Ohio, or from Circa Inc., Dayton, Ohio.
The tablet core may contain other conventional ingredients, such as fillers, which include water-soluble compressible carbohydrates such as dextrose, sucrose, mannitol, sorbitol, maltitol, xylitol, lactose, and mixtures thereof; conventional dry binders like cellulose, cellulosic derivatives, polyvinyl pyrrolidone, starch, modified starch, and mixtures thereof, and in particular microcrystalline cellulose; sweeteners like aspartame, acesulfame potassium, sucralose and saccharin; and lubricants, such as magnesium stearate, stearic acid, talc, and waxes. The tablet core may also incorporate pharmaceutically acceptable adjuvants, including, for example, preservatives, flavors, antioxidants, surfactants, and coloring agents.
The tablet core may be made by any means; its method of making is not critical to the invention. Known methods of preparing tablets include rotary compression, compacting roller technology such as a
Bunick Frank J.
Luber Joseph R.
Fubara Blessing
Hegedus Sharon H.
Mc-Neil-PPC, Inc.
Spear James M.
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