The present invention relates to a compressed, chewable tablet containing at least one active ingredient, a water-disintegratable, compressible carbohydrate and a binder. These components are dry blended and compressed into convex-shaped tablet having a hardness of about 2 to about 11 kp/cm² and friability less than 1%.

SUMMARY OF THE INVENTION

The present invention provides a compressed, chewable tablet containing at least one active ingredient, a water-disintegratable, compressible carbohydrate and a binder. These components are dry blended and compressed into a convex-shaped tablet having a hardness of about 2 to about 11 kp/cm². The tablet has a friability of less than 1%.

In a preferred embodiment of the present invention, the compressed, chewable tablet is prepared by dry blending the active ingredient, water-disintegratable, compressible carbohydrate and binder, and then compressing into a convex-shaped tablet having a hardness of about 2 to about 11 kp/cm². If the active ingredient has an objectionable taste, it is coated with a taste masking composition.

Compressing at reduced force reduces fracture of the coating used for masking the unpleasant taste of the active ingredient. These convex-shaped, chewable tablets are softer that conventional chewable tablets, which results in improvements in product taste, mouthfeel, and ease of chewing.

The convex tablet geometry significantly reduces tablet friability at a given compression force. This reduction in tablet friability allows for the use of lower compression forces and lower tablet hardness, while maintaining the ability to process the tablets with conventional bulk handling equipment and package them in conventional bottles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The compressed, chewable tablets of the present invention comprise at least one active ingredient, a water-disintegratable, compressible carbohydrate, and a binder. These ingredients are dry blended and then compressed into a convex-shaped tablet having a hardness of about 2 to about 11, preferably about 5 to about 8.5, kp/cm². Tablet friability is also preferably less than

Tableting machines, preferably those capable of applying separate pre-compression and main compression forces, are used to compress the ingredients into tablets. Since the ingredients are dry blended, water-soluble, as well as water-insoluble, active ingredients can be used in the tablet. If the active ingredients have an objectionable taste they may be coated with a taste masking composition.

The water-disintegratable, compressible carbohydrate used in the present invention includes carbohydrate materials conventionally used in tablets. The carbohydrates facilitate the breakup of the dosage form after oral administration, and are described in Lieberman et al., Pharmaceutical Dosage Forms, Marcel Dekker, Inc., New York, 2 Ed. Vol. 1, pp. 205-209 (1990), which is hereby incorporated by reference. Preferred water-disintegratable, compressible carbohydrates include mannitol, sorbitol, maltitol, dextrose, sucrose, xylitol, lactose, and mixtures thereof.

The binder in the present invention is used to add cohesiveness to the formulation, thereby providing the necessary bonding to form a cohesive mass or compact upon compression. These binders are conventionally used in direct compression tablets and are described in Lieberman et al., Pharmaceutical Dosage Forms, 2 Ed., Vol. 1, pp. 209-214 (1990), which is hereby incorporated by reference. Preferred binders include cellulose, cellulosic derivatives, polyvinyl pyrrolidone, starch, modified starch, and mixtures thereof, and, in particular, microcrystalline cellulose available from FMC Corp. under the trademark AVICEL® PH 101.

The tablets of the present invention are used to orally administer a wide variety of active ingredients. Suitable active ingredients include pharmaceuticals, minerals, vitamins and other nutraceuticals. Suitable pharmacuticals include analgesics, decongestants, expectorants, antitussives, antihistamines, gastrointestinal agents, diuretics, bronchodilators, sleep-inducing agents and mixtures thereof. Preferred pharmaceuticals include acetaminophen, ibuprofen, flurbiprofen, naproxen, aspirin, pseudoephedrine, phenylpropanolamine, chlorpheniramine maleate, dextromethorphan, diphenhydramine, famotidine, loperamide, ranitidine, cimetidine, astemizole, terfenadine, terfenadine carboxylate, cetirizine, mixtures thereof and pharmaceutically acceptable salts thereof.

The active ingredient(s) are present in the tablet in a therapeutic 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 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, a coated particle containing the active ingredient coated with a taste masking coating is employed. The active may be coated with taste masking coatings known in the art, such as those described in U.S. Pat. No. 4,851,226, issued Jul. 25, 1989, to T. W. Julian, et al.; U.S. Pat. No. 5,075,114, issued Dec. 24, 1991 to E. J. Roche; and U.S. Pat. No. 5,489,436, issued Feb. 6, 1996, all of which are hereby incorporated by reference. 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 acetaminophen may be purchased commercially from Eurand America, Inc. Vandalia, Ohio, or from Circa Inc., Dayton, Ohio.

As used in the present invention, "coated particle" refers to a solid active ingredient in the form of a crystal or particle, an agglomerate of individual particles, or a granuled particle, which has been encapsulated with a the taste masking composition, either by film coating or by another process such as coaccervation. The tablet may provide for immediate or sustained release of the active.

Taste masking compositions suitable for use as coatings are provided in the following table:

Substantially all of the active ingredient or granulated active ingredient should be coated with a layer of a taste masking composition having a thickness of about 3 to about 10 microns. The coating should be substantially free of cracks, holes or other imperfections when examined under a scanning electron microscope at 100-500x.

If taste masking is necessary, the active ingredient is preferably coated with a blend of a first polymer selected from the group consisting of cellulose acetate and cellulose acetate butyrate and a second polymer selected from the group consisting of polyvinyl pyrrolidone and hydroxypropyl cellulose. The weight ratio of the first polymer to the second polymer in this blend is within the range of about 90:10 to about 50:50 and preferably about 90:10 to about 70:30.

The blend of first and second polymers may be coated directly onto the pure active ingredient or may be coated onto a granulated particle containing the active. In the case of a granulated particle, such as a rotogranulated particle, the active will constitute from about 5 to about 90 weight percent of the particle, with the remainder being the binder or filler. Suitable binders for the granulated particles include polyvinyl pyrrolidone, hydroxypropylmethyl cellulose, hydroxypropyl cellulose, and other pharmaceutically acceptable polymers. Fillers suitable for use in such granulated particles include lactose, confectioner's sugar, mannitol, dextrose, fructose, other pharmaceutically acceptable saccharides and microcrystalline cellulose.

The coated particles may be prepared by spraying an organic solvent solution of the polymeric blend onto the active ingredient, or a granulated particle containing the active ingredient, in a fluidized bed, such as a Wurster coater or a rotogranulator. A wide variety of organic solvents may be used to prepare the solution of the polymeric blend. For example, a preferred solvent is a mixture of acetone and methanol, but other solvent systems may be employed, including methylene chloride, methylene chloride-methanol, acetone-ethyl acetate, toluene-ethanol and acetone-ethanol. Generally, the proportion of the polymer blend in the solvent solution will be within the range of about 5 to about 20, preferably about 8 to about 15, weight percent, depending on the solvent and other similar considerations.

When a fluidized bed coating operation is used, air, which may be heated, passes through a bed of the active ingredient solids to fluidize them, and the solution of the polymeric blend is sprayed onto the fluidized bed and thereby coats the active. The air passing through the bed dried the coating onto the active ingredient, so that a dry coated granule is obtained.

Conventional fluidized bed coating equipment may be used in the present invention to coat the active ingredient or the rotogranulated particle containing the pharmaceutical. This equipment includes Wurster fluid-bed coaters, where the solution of the polymer blend is sprayed from the bottom of the chamber, and a rotogranulator, where the solution of the polymer blend is tangentially sprayed. These coating operations are further described in Lieberman et al., Pharmaceutical Dosage Forms, Marcel Dekker, Inc., New York, Vol. 3, pp. 138-150 (1990), which is hereby incorporated by reference.

The coated particle, in a dried state, generally contains about 5 to about 60, preferably about 10 to 40, weight percent of the blend of the first and second polymers. The exact proportions of the coating to the active ingredient can, however, vary depending upon the level of taste masking required and whether a sustained or immediate release of the active is desired. Larger proportions of the coating tend to provide a sustained release effect and enhance taste masking.

The tablet may also contain ingredients other than the coated particles, carbohydrate and binder. The additional ingredients include sweeteners, such as aspartame, acesulfame potassium, sucralose and saccharin; and lubricants, such as magnesium stearate, stearic acid, talc, and waxes. The dosage form may also incorporate pharmaceutical acceptable adjuvants. Such adjuvants, include, for example, preservatives, flavors, antioxidants, surfactants, and/or colors.

The tablets, on a dry basis, generally comprise from about 0.1 to about 60, preferably about 12 to about 25, percent by weight of the active ingredient; from about 30 to about 90, preferably about 40 to about 65, percent by weight of the water-disintegratable, compressible carbohydrate material; from about 1 to about 30, preferably about 5 to about 20, percent by weight of the binder; from about 0.1 to about 5, preferably about 0.5 to about 1.5, percent by weight of the lubricant; from 0 to about 5, preferably about 0.1 to about 3.0, percent by weight of the sweetener; from 0 to about 5, preferably about 0.2 to about 2.0, percent by weight of the flavor; and from 0 to about 5, preferably about 0.01 to about 0.4, percent by weight of the color.

The unit weight of the tablet will vary depending on the dosage of the active ingredient. The unit weight will generally range from about 250 to about 1000 mg. A typical dosage form may contain:

If taste masking is required, coated particles of the active ingredient are prepared using the aforementioned techniques. The particle size of the coated particles, as well as the remaining components, is generally less than 600 microns. The components of the tablet are then dry mixed to form a uniform powder blend. The blend is then compressed into a tablet of the desired hardness using conventional compression tableting techniques.

In a preferred embodiment of the invention, the compressed, chewable tablet has a convex or bi-convex shape and is relatively soft so as to provide good mouthfeel and taste and ease of chewing. Generally, the tablet will have a diameter of about 7 to about 19, preferably about 9 to about 13, mm and a thickness of about 2 to about 12, preferably about 3 to about 8, mm.

FIGS. 1a and 1b are, top and side views, respectively, of a bi-convex tablet 10 of the present invention (see Original Patent).

The external pressure applied by the tablet press during the compression step is controlled so that the hardness of the tablet is within the range of about 2 to about 11, preferably about 5 to about 8.5, kiloponds (kp) per sq. cm (cm²). Tablet breaking strength, or hardness, is dependent on cross-sectional area at the tablet breaking point. In order to compare values across different size tablets, the breaking strength must be normalized for the area of the break. This normalized value, expressed in kp/cm² is often referred in the art as tablet tensile strength. Hardness is measure by conventional pharmaceutical hardness testing equipment, such as a Schleuniger Hardness Tester.

During tableting it is preferable to apply the compression forces in two steps. A pre-compression pressure of about 2 to about 17, preferably about 5.5 to about 11.5, kN/cm² is applied. The main compression pressure of about 3 to about 18, preferably about 7 to about 13, kN/cm² is then applied to complete the compression operation. Alternatively, the tablet may be formed in one compression step using a compression pressure of about 3 to about 18, preferably about 7 to about 13, kN/cm².

The compressed, chewable tablet has a friability of less than 1%, preferably less than 0.5%. In the present invention, tablet friability is determined in accordance with USP Method <1216> Tablet Friability, USP 23 (1995) and is expressed as percent weight loss. As shown in FIG. 2, as the hardness of a tablet produced with flat face, beveled edge tooling is reduced, friability increases. However, when the hardness of a convex tablet of the present invention produced with concave tooling decreases, friability remains substantially constant. These findings are unexpected in view of the friability reported by Chakrabarti et al. and Sugimori et al., supra, for convex tablets.

These findings are significant because the tablets of the present invention can be compressed at lower compression forces, but still maintain acceptable friability. This results in a softer tablet having improved product taste, mouthfeel and ease of chewing. Compressing at reduced forces also reduces the probability of fracturing the coating used for masking the unpleasant taste of the active ingredient.
 

Claim 1 of 10 Claims

1. A product produced by the process, comprising the steps of:

dry mixing at least one taste-masked coated active ingredient selected from acetaminophen, a water-disintegratable, compressible carbohydrate and a binder; and

compressing the mixture into a tablet having convex shaped opposed face surfaces and a hardness of about 2 to about 11 kp/cm².
 

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