United States Patent 6,814,978: Claim Scope, Expiration, and Pharmaceutical Tablet Patent Landscape

United States Patent No. 6,814,978 covers chewable and disintegrative tablets that combine a pharmaceutical active ingredient with a hydrate excipient and a water-swellable excipient. Its central process requires forming a low-friability tablet and then applying heat to reduce tablet hardness by at least 20%. The patent does not claim any particular drug molecule, therapeutic indication, or dosage strength.

The patent’s practical commercial value was concentrated in manufacturing methods for soft, robust chewable tablets, especially formulations using dextrose monohydrate and crospovidone. Its United States patent term has ended, eliminating current United States infringement exposure under the asserted claims.

What does United States Patent 6,814,978 cover?

The patent has two principal claim categories:

A composition claim directed to a tablet containing:
- a pharmaceutically active ingredient;
- dextrose monohydrate; and
- crospovidone.
Process claims directed to producing a chewable or disintegrative tablet by:
- forming a tablet from an active ingredient, a hydrated excipient, and a water-swellable excipient;
- achieving a specified friability;
- applying heat; and
- reducing tablet hardness by at least about 20%.

The claims are directed to dosage-form architecture and manufacturing conditions. They do not claim acetaminophen, ibuprofen, pseudoephedrine, or another active ingredient independently.

Patent identification and term

Item	Information
Patent	U.S. Patent No. 6,814,978
Patent type	Utility patent
Technology	Chewable and disintegrative tablets
Issue date	November 9, 2004
Core subject matter	Hydrate excipients, water-swellable excipients, heat-softened tablets
Principal claim types	Composition, process, product-by-process
United States status	Expired by statutory term
Orange Book relevance	No apparent current Orange Book exclusivity based on the claims alone
Biosimilar relevance	None; the patent concerns small-molecule tablet technology

The expiration date depends on the patent’s effective nonprovisional filing date and any applicable patent-term adjustment. The patent’s enforceable term ended no later than the early 2020s. A patent that has expired cannot support a current United States infringement action for post-expiration conduct, although it may remain relevant to historical litigation, prosecution history, freedom-to-operate records, and technical disclosures.

What does claim 1 of U.S. Patent 6,814,978 protect?

Claim 1 covers:

A tablet comprising a pharmaceutically active ingredient, dextrose monohydrate, and crospovidone.

This is a three-component composition claim. The active ingredient is unrestricted, except that it must be pharmaceutically active. The claim therefore reaches a broad range of finished tablets if the tablet contains both named excipients.

Claim 1 limitation analysis

Limitation	Scope
Tablet	Requires a compressed or otherwise formed solid dosage unit
Pharmaceutically active ingredient	Broad; no specific drug, dose, salt, or indication required
Dextrose monohydrate	Required specific hydrate excipient
Crospovidone	Required specific water-swellable excipient
Heat treatment	Not required by claim 1
Hardness	Not required unless claim 2 is asserted
Friability	Not required
Chewability	Not expressly required
Disintegration performance	Not expressly required

A tablet containing acetaminophen, dextrose monohydrate, and crospovidone could fall within claim 1 without satisfying the heat-treatment process in claim 3. Conversely, a tablet that uses a different hydrate, such as lactose monohydrate, does not literally satisfy claim 1 because dextrose monohydrate is expressly required.

Claim 1 does not require a particular concentration of dextrose monohydrate or crospovidone. It also does not specify whether the active ingredient is present as a free base, acid, salt, solvate, polymorph, or mixture.

How does claim 2 narrow the tablet claim?

Claim 2 depends on claim 1 and requires tablet hardness of less than about 15 kp/cm2.

The claim adds a measurable physical property but leaves the composition requirements unchanged. A product must therefore contain the three elements of claim 1 and satisfy the hardness limitation.

The phrase “less than about 15 kp/cm2” introduces ordinary analytical issues:

the hardness test method;
tablet diameter and geometry;
instrument calibration;
sampling size;
compression orientation;
treatment of outlier results; and
the meaning of “about.”

Those issues can affect infringement analysis. A manufacturer with a tablet hardness near the 15 kp/cm2 boundary would need a validated testing protocol and historical batch data.

What does claim 3 protect?

Claim 3 is the broadest process claim. It requires a process for preparing a chewable or disintegrative tablet comprising the following steps:

Forming a tablet from a mixture containing:
- a pharmaceutically active ingredient;
- an excipient in the form of a hydrate; and
- a water-swellable excipient.
Producing the tablet with friability below 2%.
Applying sufficient heat for sufficient time to decrease tablet hardness by at least about 20%.

Claim 3 does not restrict the active ingredient to the list in claim 8. It also does not restrict the hydrate excipient or water-swellable excipient to the lists in claims 9 and 10.

Claim 3 limitation analysis

Required element	Technical significance
Chewable or disintegrative tablet	Limits the process to a functional dosage-form category
Active ingredient	Broad drug limitation
Hydrate excipient	Requires an excipient containing water of crystallization or hydration
Water-swellable excipient	Requires a swelling or disintegrating excipient
Friability below 2%	Requires a mechanically robust tablet before or during the claimed process, depending on construction
Heat application	Requires thermal treatment after tablet formation
Hardness reduction of at least about 20%	Requires comparison between pre-heat and post-heat hardness

The key inventive concept is the combination of initial tablet robustness and subsequent heat-induced softening. The process seeks to produce a tablet that can withstand handling and packaging while acquiring a lower final hardness suitable for chewing or rapid disintegration.

What are the dependent claims and their commercial implications?

Claim 4: direct compression

Claim 4 requires that the tablet be formed by direct compression. It excludes processes that use wet granulation or other manufacturing routes unless the process also satisfies the direct-compression limitation.

This claim is relevant to manufacturers using a dry blend of active ingredient, hydrate excipient, water-swellable excipient, lubricants, flavors, sweeteners, and other conventional tableting ingredients.

Claim 5: final hardness below 15 kp/cm2

Claim 5 requires the final tablet hardness to be below approximately 15 kp/cm2. It provides a narrower process claim than claim 3 and may be easier to test against finished-product samples than the 20% reduction limitation.

Claim 6: low friability and soft final tablet

Claim 6 requires:

friability below 1%; and
final hardness of approximately 1 to 8 kp/cm2.

This is the most commercially targeted hardness claim. It describes a tablet that remains resistant to chipping and breakage while becoming substantially softer after heat treatment.

Claim 7: packaging before heating

Claim 7 covers a process in which the tablet is packaged before heat application. The limitation may reach processes using a package or container as part of the thermal-conditioning sequence.

This claim can be important where the thermal step occurs after primary packaging, such as heating sealed blister packs, bottles, pouches, or other commercial packages. It does not necessarily require that the package itself provide the heat.

Claim 8: specified active ingredients

Claim 8 lists:

acetaminophen;
ibuprofen;
pseudoephedrine;
dextromethorphan;
diphenhydramine;
chlorpheniramine;
calcium carbonate;
magnesium hydroxide;
magnesium carbonate;
magnesium oxide;
aluminum hydroxide;
mixtures of those ingredients; and
pharmaceutically acceptable salts.

This claim targets common over-the-counter analgesic, cold, allergy, antitussive, and antacid products. It does not cover every active ingredient. A formulation using an active outside the list can still fall within claim 3, but not claim 8.

Claim 9: hydrate excipients

Claim 9 identifies the following hydrate excipients:

dextrose monohydrate;
maltodextrin hydrate;
lactose monohydrate;
dextrin hydrate;
citric acid monohydrate;
dibasic calcium phosphate dihydrate;
dibasic sodium phosphate dihydrate;
dibasic sodium phosphate heptahydrate;
dibasic sodium phosphate dodecahydrate;
monobasic sodium phosphate monohydrate; and
monobasic sodium phosphate dihydrate.

Claim 9 is materially broader than claim 1 because claim 3 can be narrowed to numerous hydrates rather than only dextrose monohydrate.

Claim 10: water-swellable excipients

Claim 10 identifies:

sodium starch glycolate;
crospovidone;
croscarmellose;
microcrystalline cellulose;
starches; and
alginic acid.

The list covers conventional superdisintegrants and swelling excipients. Claim 10 therefore reaches more formulation designs than claim 1, which requires crospovidone specifically.

Claims 11 and 12: concentration ranges

Claim 11 requires the hydrate excipient to comprise approximately 5% to 90% by weight of the tablet.

Claim 12 requires the water-swellable excipient to comprise approximately 0.1% to 5% by weight.

These ranges are commercially important because they define a substantial portion of typical tablet formulations while excluding formulations outside the stated boundaries. A formulation with 4% hydrate excipient or more than 5% water-swellable excipient may avoid literal infringement of the respective dependent claim while remaining potentially relevant to claim 3.

Claim 13: direct-compression filler

Claim 13 requires that the hydrate excipient function as a direct-compression filler. The claim focuses on excipient role, not merely chemical identity.

A hydrate excipient may be present in the tablet yet not function as the principal direct-compression filler. The technical question would depend on formulation design, excipient grade, compression behavior, and manufacturing records.

Claim 14: product produced by the process

Claim 14 covers a tablet produced by the process of claim 3.

This is a product-by-process claim. Its scope depends on the applicable interpretation of product-by-process limitations. The claim does not simply cover every tablet having the listed ingredients. It is tied to a tablet produced through the claimed process, including the heat treatment that reduces hardness by at least about 20%.

How strong is the patent estate for U.S. Patent 6,814,978?

The patent estate was technically meaningful but structurally narrow in several respects.

Strengths

Claim 1 broadly covers any active ingredient when combined with dextrose monohydrate and crospovidone.
Claim 3 covers a wide range of hydrate and water-swellable excipients.
The process claims target manufacturing conditions that may be difficult to identify from a finished product alone.
Claim 7 reaches post-packaging heat treatment.
Claims 8 through 12 capture common OTC actives and conventional excipient levels.

Limitations

The patent does not claim the active ingredients themselves.
The composition claims require specified excipients.
The process claims require heat treatment and a measurable hardness reduction.
The claims require tablet friability and hardness conditions that may vary with test methodology.
A formulation using a non-hydrate filler may avoid the central process claims.
A formulation using a non-water-swellable excipient may avoid claims 3 through 14.
Expiration removes current United States enforcement value.

The estate would have been strongest against a manufacturer using a listed OTC active, a listed hydrate such as dextrose monohydrate or lactose monohydrate, a listed superdisintegrant such as crospovidone, direct compression, and post-compression heat conditioning.

What design-arounds could avoid the patent claims?

Potential design-around paths include:

Design-around	Claims potentially avoided
Replace dextrose monohydrate with an anhydrous filler or non-hydrate excipient	Claim 1 and hydrate-dependent claims
Replace crospovidone with a non-water-swellable disintegrant or alternative excipient	Claim 1 and crospovidone-specific exposure
Use wet granulation rather than direct compression	Claim 4 and claim 13
Eliminate the heat-softening step	Claims 3 through 14
Apply heat without reducing hardness by at least about 20%	Claims 3 through 14
Produce final hardness above 15 kp/cm2	Claims 2 and 5, but not necessarily claim 3
Use a formulation outside the claimed excipient ranges	Claims 11 and 12
Use an active ingredient outside the claim 8 list	Claim 8 only, not claim 3
Use a non-chewable, non-disintegrative tablet	Potentially claim 3, subject to dosage-form construction

Because the patent is expired, these design-arounds now have historical or portfolio-analysis value rather than current United States infringement significance.

What is the Orange Book status of U.S. Patent 6,814,978?

The patent claims tablet compositions and manufacturing processes rather than a specific approved drug product, active ingredient, dosage form identified by brand, or method of use approved in labeling.

On that basis, the patent does not appear to provide current Orange Book exclusivity. Orange Book listing is generally associated with patents claiming an approved drug substance, drug product, formulation, composition, or method of use submitted for an approved product under the applicable FDA listing framework. A broad formulation or manufacturing patent can be relevant to a marketed drug without creating a current Orange Book barrier.

The patent also does not create an abbreviated new drug application Paragraph IV obstacle after expiration. A generic applicant would not face a live Paragraph IV certification requirement based solely on an expired patent.

Are there Paragraph IV challenges or generic litigation?

No current Paragraph IV exposure follows from this expired patent. The claims are directed to dosage-form technology and are not directed to a drug substance patent or method-of-use patent for a particular branded product.

The supplied claims do not identify:

an FDA reference listed drug;
a branded product;
an Orange Book-listed patent;
a Paragraph IV notice letter;
a district court infringement action;
an ITC investigation; or
a settlement agreement.

The patent’s expiration is the controlling legal event for present United States freedom-to-operate analysis. Historical litigation or settlement activity, if any, would not restore the expired patent’s exclusionary term.

Does the patent create biosimilar risk?

No. U.S. Patent 6,814,978 concerns conventional small-molecule tablets and does not claim:

a biologic active ingredient;
a recombinant protein;
an antibody;
a cell or gene therapy;
a biosimilar manufacturing platform; or
a biologics license application exclusivity period.

Biosimilar applicants would not rely on this patent as a principal barrier. The relevant competitive pathway would be an ANDA or, for certain products, another small-molecule FDA pathway.

What manufacturing and intellectual-property barriers did the patent create?

During its term, the patent could have created barriers in three areas:

Formulation selection. A product using a hydrate filler and water-swellable excipient could have implicated the composition or process claims.
Thermal conditioning. Heat treatment that reduced tablet hardness by at least 20% could have implicated the central process limitation.
Packaging and process integration. Heating tablets after packaging could have implicated claim 7.

The most difficult technical limitation to assess from public product information is the hardness reduction requirement. It requires comparative data before and after heating. A competitor could have used laboratory testing, reverse engineering, regulatory samples, or manufacturing records to evaluate that limitation.

How does this patent compare with ordinary formulation patents?

Issue	U.S. Patent 6,814,978	Typical drug substance patent	Typical method-of-use patent
Claimed subject	Tablet composition and process	Active molecule or chemical entity	Treatment method
Active ingredient specificity	Broad or listed OTC actives	Usually highly specific	Disease and patient-specific
Manufacturing limitation	Extensive	Often limited	Usually absent
Orange Book relevance	Limited	Often high	Often high
Generic impact	Product/process formulation design	Core product launch timing	Labeling and carve-out strategy
Biosimilar relevance	None	None for small molecules	None
Current enforceability	Expired	Depends on term	Depends on term

The patent was more relevant to formulation and manufacturing freedom to operate than to active-ingredient exclusivity. Its commercial impact would have depended on whether a marketed product used the claimed excipient combinations and thermal process.

What is the competitive landscape for chewable tablet technology?

Relevant competing technologies include:

directly compressed chewable tablets;
wet-granulated chewable tablets;
orally disintegrating tablets;
soft-chew or gummy dosage forms;
effervescent tablets;
tablets using mannitol, sorbitol, xylitol, or maltitol;
tablets using crospovidone, croscarmellose, or sodium starch glycolate;
molded tablets; and
coated or taste-masked tablets.

The patent’s technical distinction is the use of a hydrated excipient and a water-swellable excipient followed by heat treatment to reduce hardness. Competing manufacturers could avoid the claim architecture through different fillers, different disintegrants, alternate compression techniques, or nonthermal softening processes.

What was the revenue exposure associated with the patent?

The patent itself does not establish revenue attributable to any particular product. The claims encompass common OTC actives, including acetaminophen, ibuprofen, cough and cold ingredients, and antacid ingredients, but they do not identify a commercial brand.

Revenue exposure would therefore have depended on:

whether a company used the claimed tablet architecture;
the number of marketed products using the process;
the share of sales attributable to the United States;
whether the patent was listed or licensed;
the availability of noninfringing alternatives; and
the patent’s remaining term at the time of product launch.

Because the patent has expired and the claims do not identify a specific product, it should not be treated as a current revenue barrier without separate product-level evidence.

What is the geographic coverage of the patent?

U.S. Patent 6,814,978 provided rights only in the United States. Its claims did not automatically extend to:

Canada;
Europe;
Japan;
China;
Australia;
India; or
other jurisdictions.

Foreign counterparts, if any, would require separate review of their publication numbers, prosecution history, claim amendments, term adjustments, and expiration dates. The U.S. patent cannot be used to establish foreign infringement or foreign exclusivity.

Key Takeaways

U.S. Patent 6,814,978 covers chewable and disintegrative tablet technology, not a particular drug molecule.
Claim 1 requires an active ingredient, dextrose monohydrate, and crospovidone.
Claim 3 requires a hydrate excipient, a water-swellable excipient, low friability, heat treatment, and at least about a 20% hardness reduction.
Claims 8 through 10 identify common OTC actives and excipient classes.
Claims 11 and 12 establish hydrate and water-swellable excipient concentration ranges.
Claim 14 is a product-by-process claim tied to the process of claim 3.
The patent’s United States term has expired, eliminating current United States infringement exposure.
The claims do not create current biosimilar risk.
The patent does not appear to provide current Orange Book exclusivity based on the claim language.
Its principal historical value was as a formulation and manufacturing barrier for heat-softened OTC chewable tablets.

FAQs

Can a tablet containing acetaminophen and crospovidone infringe U.S. Patent 6,814,978?

Not under claim 1 unless it also contains dextrose monohydrate. Claims 3 and 8 could be relevant only if the product was made through the claimed heat-treatment process and satisfied the process limitations.

Does using lactose monohydrate avoid claim 1?

Yes, lactose monohydrate does not literally satisfy claim 1, which requires dextrose monohydrate. Lactose monohydrate may still be relevant to claim 9 if the other process requirements are satisfied.

Does heating a tablet automatically satisfy the patent?

No. The process must include a hardness reduction of at least about 20%, along with the active ingredient, hydrate excipient, water-swellable excipient, and friability requirements.

Can an expired formulation patent block an ANDA?

An expired patent cannot create a current United States patent-based launch bar. It may remain relevant to historical validity, litigation, licensing, or regulatory records, but it does not provide enforceable exclusivity after expiration.

Does claim 14 cover every soft chewable tablet?

No. Claim 14 is tied to a tablet produced by the process of claim 3. A soft tablet made without the claimed hydrate, water-swellable excipient, friability, heat, and hardness-reduction steps is not automatically within claim 14.

References

United States Patent No. 6,814,978, “Chewable Tablets and Methods of Making Same,” issued November 9, 2004.
United States Patent and Trademark Office. (2024). Manual of Patent Examining Procedure, Chapter 2700: Patent Term and Adjustment.
United States Patent and Trademark Office. (2024). Patent Center and Patent Examination Data System.
U.S. Food and Drug Administration. (2024). Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book.
U.S. Food and Drug Administration. (2024). ANDA Submissions: Content and Format of an ANDA.
35 U.S.C. §§ 154, 271, and 282.
21 U.S.C. § 355(j).

Summary for Patent: 6,814,978