US Patent 6,723,348: Fexofenadine Orodispersible Tablet Claims, Scope, Expiration, and Patent Landscape

US Patent 6,723,348 covers a specific fexofenadine orally disintegrating tablet architecture. Its central requirement is a tablet containing fexofenadine in coated-granule form combined with a disintegrant, soluble diluent, and lubricant, with buccal disintegration in less than 60 seconds. The patent issued on April 20, 2004, and its nominal 20-year term ran from the relevant U.S. filing date to approximately March 2021. The patent is therefore no longer a live U.S. exclusion right, subject to any recorded term adjustment or other statutory extension. [1]

The claims are important historically because they protect a formulation and delivery format rather than fexofenadine as an active pharmaceutical ingredient. The patent does not broadly cover every fexofenadine tablet, orally disintegrating dosage form, or rapid-disintegration formulation.

What does US Patent 6,723,348 cover?

The patent covers orally disintegrating fexofenadine tablets with four central technical characteristics:

Fexofenadine base or a pharmaceutically acceptable salt.
Fexofenadine present as coated granules.
An excipient mixture containing a disintegrant, soluble diluent, and lubricant.
Disintegration in the buccal cavity upon contact with saliva in less than 60 seconds, producing an easy-to-swallow suspension.

Claim 1 is the principal composition claim. The remaining composition claims narrow the formulation by adding specific excipients, ratios, particle sizes, concentrations, or performance limitations.

The independent method-of-treatment claim, claim 14, covers oral administration of the claimed orodispersible tablet for symptoms associated with seasonal allergic rhinitis. Claim 15 adds a human bioequivalence limitation relative to an Allegra tablet.

Claim 1: core composition scope

Claim 1 is a combination claim. Literal infringement requires the accused product to satisfy all material limitations. The claim does not cover a formulation merely because it contains fexofenadine and disintegrates rapidly.

The principal narrowing limitation is the requirement that fexofenadine be present in “the form of coated granules.” A conventional directly compressed fexofenadine powder, uncoated granulation, liquid-filled system, capsule, or conventional swallowed tablet would fall outside the literal language of that limitation unless the coated-granule requirement were met under an applicable doctrine of equivalents.

The excipient requirement is also cumulative. The formulation must include:

At least one disintegrating agent;
A soluble diluent agent; and
A lubricant.

A formulation using a disintegrant and filler but no lubricant would not literally satisfy claim 1. The claim also requires the stated buccal performance, although the patent’s test method and construction of “less than 60 seconds” would be relevant in litigation.

How do claims 2 through 17 narrow the patent?

Claim	Added limitation	Commercial or technical effect
1	Coated fexofenadine granules; disintegrant; soluble diluent; lubricant; disintegration under 60 seconds	Broadest composition claim
2	Disintegration in less than 40 seconds	Faster-disintegration subset
3	Swelling, antistatic, permeabilizing, sweetening, flavoring, or coloring agents	Additional excipient options
4	Excipient-to-coated-granule weight ratio of 0.4:1 to 9:1	Broad formulation ratio
5	Ratio of 1.5:1 to 5:1	Narrower ratio
6	Ratio of 2:1 to 3:1	Narrowest ratio in this series
7	Croscarmellose, crospovidone, or both	Specific disintegrants
8	Polyol soluble diluent with specified particle-size and compression characteristics	Detailed diluent architecture
9	Disintegrant at 3%-15%; soluble diluent at 30%-90%	Weight-percent limitations
10	Disintegrant at 5%-15%; soluble diluent at 40%-60%	Narrower concentration range
11	Listed lubricants, including magnesium stearate and sodium stearyl fumarate	Specific lubricant set
12	Listed sweeteners	Taste-masking subset
13	Powder lubricant at least partly located on tablet surface	Surface-lubrication configuration
14	Treatment of seasonal allergic rhinitis	Method-of-treatment claim
15	Human bioequivalence to Allegra tablet	Performance-based product limitation
16	Mannitol, xylitol, sorbitol, or maltitol as polyol	Specific polyol group
17	Directly compressible-to-powder polyol ratio of 80:20 to 20:80	Narrower polyol blend ratio

Claims 4 through 6 create a nested ratio structure. An accused formulation with an excipient-to-granule ratio of 2.5:1 may fall within claims 4, 5, and 6 if all other requirements are present. Claims 9 and 10 operate similarly for excipient concentration.

What formulations are protected by the fexofenadine patent?

The strongest commercial embodiment is a rapidly disintegrating tablet using coated fexofenadine granules, mannitol or another polyol as the soluble diluent, croscarmellose or crospovidone as the disintegrant, and magnesium stearate or another listed lubricant.

Claim 8 adds substantial formulation detail. It requires a polyol with fewer than 13 carbon atoms, including mannitol, xylitol, sorbitol, and maltitol. The claim distinguishes between:

A directly compressible polyol with an average particle size of 100 to 500 micrometers; and
A powdered polyol with an average particle size below 100 micrometers.

If only one soluble diluent with binding properties is used, it must be in directly compressible form. If two are used, one may be directly compressible and the other powdered. The directly compressible-to-powder ratio is 99:1 to 20:80 under claim 8 and 80:20 to 20:80 under claim 17.

The claim language suggests that the invention relies on balancing rapid wetting and disintegration against sufficient tablet strength for manufacture, packaging, and handling.

Coated-granule significance

The coating can perform several formulation functions:

Separating fexofenadine from excipients;
Reducing taste or mouthfeel problems;
Controlling exposure of the active ingredient to saliva;
Improving powder flow and compressibility;
Supporting a rapid, uniform suspension after tablet disintegration.

The patent’s scope depends on what qualifies as a “coated granule.” A granule with a polymeric, film-forming, protective, taste-masking, or functional coating could be relevant. The coating composition, thickness, manufacturing process, and whether the active is embedded or merely agglomerated would likely become central claim-construction issues.

How strong is the patent estate for US Patent 6,723,348?

The patent has moderate historical formulation strength but limited breadth.

Strengths

Claim 1 combines several commercially relevant formulation limitations.
The claim covers both fexofenadine base and pharmaceutically acceptable salts.
Dependent claims provide fallback positions for common excipients and manufacturing ratios.
Claims 2 and 15 add measurable performance limitations.
The patent addresses a recognizable dosage form associated with pediatric and swallowing-convenience products.

Limitations

The coated-granule requirement excludes many noncoated or differently structured formulations.
The excipient combination is specific and may be avoided through alternative diluents, lubricants, or processing approaches.
The disintegration-time limitation may depend on test conditions, tablet size, medium, apparatus, and endpoint definition.
Claim 15 requires a bioequivalence relationship to an Allegra tablet, which may create proof and construction issues.
The method claim is limited to seasonal allergic rhinitis rather than all indications for fexofenadine.
The patent has reached the end of its ordinary U.S. term.

The patent was therefore more relevant as a product-specific formulation barrier than as a fundamental fexofenadine platform patent.

When did US Patent 6,723,348 lose exclusivity?

The patent’s nominal U.S. term expired in approximately March 2021, based on the relevant March 2001 U.S. filing or national-stage date and the 20-year patent-term rule applicable to post-1995 applications. [1, 2]

Event	Date or status
Relevant U.S. filing period	Approximately March 2001
Patent issuance	April 20, 2004
Nominal 20-year expiration	Approximately March 2021
Current status	Expired by term, absent a recorded extension
Current enforceability	No ordinary prospective patent exclusion remains

Patent term adjustment could alter the precise expiration date. The patent’s publication and issue records should be checked for the final term calculation before relying on a specific day in litigation, freedom-to-operate, or licensing documentation.

There is no apparent basis for pediatric exclusivity or patent-term extension to materially extend this formulation patent. Fexofenadine is a small molecule, not a biologic, so biosimilar exclusivity rules do not apply.

What is the Orange Book status of the patent?

The Orange Book relevance of US 6,723,348 depends on the particular Allegra product and the regulatory listing history. Allegra products have included tablets, capsules, orally disintegrating products, and oral suspensions, while fexofenadine products have also been sold over the counter.

A patent may be listed in the Orange Book only if it satisfies FDA listing requirements for the relevant approved drug product. A formulation patent covering an orally disintegrating tablet does not automatically block an ANDA directed to a conventional fexofenadine tablet or capsule.

The practical regulatory consequences are:

An Orange Book listing would have been relevant to a generic applicant making a Paragraph IV certification during the patent term.
An expired patent does not create a current Hatch-Waxman stay or launch prohibition.
Products approved under an OTC monograph or outside an NDA may not have the same Orange Book listing framework as prescription NDA products.
The presence of a patent number in an Orange Book entry would not expand the patent’s claim scope beyond the issued claims.

The FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations remains the controlling source for current patent-listing and exclusivity records. [3]

What Paragraph IV challenges and litigation affected the patent?

A Paragraph IV certification could historically have challenged the patent as invalid, unenforceable, or not infringed if the patent were listed against an eligible NDA. The supplied claim set alone does not establish that a particular generic applicant filed a Paragraph IV notice or that a specific district-court action was brought.

Because the patent has expired, a new Paragraph IV challenge would not ordinarily provide a meaningful current market-access advantage. The relevant historical questions would have been:

Whether the patent was listed for the reference product;
Whether an ANDA applicant targeted the orally disintegrating dosage form;
Whether the applicant used coated granules;
Whether the generic formulation met the disintegration-time limitation; and
Whether any litigation produced a 30-month stay or settlement restriction.

No current injunction, 30-month stay, or enforceable settlement barrier follows from the patent’s ordinary expiration. FDA approval and market entry would remain subject to other regulatory, manufacturing, trademark, and product-quality requirements.

What generic launch risks exist for fexofenadine orodispersible tablets?

For a current entrant, US 6,723,348 is no longer the principal patent risk. The more relevant issues are formulation development, regulatory pathway, trade dress, flavoring, product performance, and any separate patents covering a particular product or manufacturing process.

A generic or private-label developer could pursue several design strategies:

Use uncoated fexofenadine granules;
Use a different granule architecture;
Select a soluble diluent outside the claimed polyol system;
Use a different disintegrant or lubricant;
Develop a tablet that does not meet the claimed buccal-disintegration performance;
Market a conventional tablet, capsule, suspension, or non-ODT dosage form;
Use a different excipient ratio or manufacturing process.

These strategies would have mattered most before expiration. Today, the patent’s technical disclosures may still be relevant for formulation design, but its claims do not ordinarily prevent commercialization.

How does this patent compare with broader fexofenadine patent protection?

US 6,723,348 is narrower than patents directed to:

Fexofenadine or its salts as chemical entities;
Broad therapeutic uses;
General pharmaceutical compositions;
Conventional immediate-release tablets;
Extended-release delivery;
Oral suspensions;
Specific manufacturing processes.

Its protected subject matter is best classified as a dosage-form and formulation patent. It does not establish ownership of fexofenadine itself. A competitor using fexofenadine in a different dosage form would not necessarily implicate any claim.

The patent also has no biosimilar dimension. Fexofenadine is a small-molecule antihistamine, and generic substitution is governed by the ANDA framework rather than the abbreviated biologics pathway.

What licensing or settlement rights attach to the patent?

The patent record and the supplied claims do not establish a current license, covenant not to sue, cross-license, or settlement agreement. Any historical licensing arrangement would need to be evaluated separately from the patent’s issued claims.

After expiration, a patent license normally has little prospective exclusion value unless it includes independent contractual restrictions, royalty obligations, know-how provisions, or confidential manufacturing rights. The patent itself cannot support a new royalty demand for post-expiration practice of the claimed invention.

Key Takeaways

US Patent 6,723,348 covers fexofenadine orodispersible tablets with coated fexofenadine granules, a disintegrant, soluble diluent, and lubricant.
Claim 1 requires buccal disintegration in less than 60 seconds and formation of an easy-to-swallow suspension.
Claims 2 through 17 narrow the invention through disintegration time, excipients, particle size, ratios, concentrations, bioequivalence, and treatment use.
The coated-granule limitation is the principal scope constraint and a potential design-around point.
The patent is a formulation patent, not a broad fexofenadine compound patent.
Its ordinary U.S. patent term expired in approximately March 2021.
No current Paragraph IV stay, injunction, or biosimilar issue follows from this patent.
Current commercial risk is more likely to arise from separate patents, regulatory requirements, trademarks, manufacturing know-how, and product-quality controls.

FAQs

Does US Patent 6,723,348 cover all Allegra orally disintegrating tablets?

No. It covers only products satisfying every limitation of the asserted claim, including coated fexofenadine granules, the specified excipient combination, and the required disintegration performance.

Can a fexofenadine tablet avoid the patent by using uncoated granules?

An uncoated formulation may avoid literal infringement of the coated-granule limitation. Equivalence would depend on the technical facts, claim construction, prosecution history, and the specific coating function.

Does claim 15 require the product to be marketed under the Allegra brand?

No. Claim 15 defines a bioequivalence relationship to an Allegra tablet. It does not require use of the Allegra trademark.

Is a fexofenadine suspension covered by this patent?

Not by the claims provided. The claims are directed to orodispersible tablets. A liquid suspension would not ordinarily satisfy the tablet limitation.

Does expiration eliminate all barriers to launching a fexofenadine ODT?

No. Patent expiration removes this patent’s ordinary exclusion right. A launch may still require compliance with the applicable FDA pathway, labeling rules, manufacturing standards, trademark restrictions, and any separate unexpired patent rights.

References

United States Patent and Trademark Office. (2004). Orodispersible tablets containing fexofenadine, U.S. Patent No. 6,723,348 B2.
United States Code. (2023). 35 U.S.C. § 154: Contents and term of patents; provisional rights.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA, Center for Drug Evaluation and Research.
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations, patent and exclusivity information. FDA, Center for Drug Evaluation and Research.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	335483	⤷ Start Trial
Australia	2002356786	⤷ Start Trial
Canada	2466580	⤷ Start Trial
China	101849917	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,723,348

Summary for Patent: 6,723,348