United States Patent 5,648,093: Claim Scope, Expiration, and Fast-Dissolving Dosage-Form Patent Landscape

US Patent 5,648,093 covers fast-dispersing solid dosage forms built around a porous matrix containing a matrix-forming agent and one or more amino acids. The patent is a platform formulation patent, not a patent directed to a specific active pharmaceutical ingredient. Its core protection requires both a porous, rapidly water-dispersible dosage form and defined matrix-processing conditions involving lyophilization or solid-state dissolution.

The patent issued July 15, 1997, and its enforceable term has expired. On the information provided, US 5,648,093 does not create a current US blocking right against generic or branded products. Its technical disclosure remains relevant as prior art and as a source of formulation concepts.

What does US Patent 5,648,093 protect?

The patent protects porous, rapidly dispersing solid dosage forms that use amino acids as part of the matrix composition. The principal embodiments include:

Glycine-containing matrices.
Gelatin, mannitol, or gelatin-mannitol matrices.
Lyophilized dosage forms.
Dosage forms produced by solid-state dissolution.
Foam dosage forms containing dispersed gas.
Dosage forms containing active pharmaceutical ingredients.
Particulate active ingredients coated with hydrophobic materials.
Formulations containing xanthan gum, cyclodextrins, magnesium trisilicate, or magnesium aluminum silicate.
Dosage forms that disperse in water in less than approximately 10 seconds.

The claims do not identify a particular drug, therapeutic indication, strength, tablet shape, or route of administration. The patent therefore operates as a formulation-platform patent rather than a compound, composition-of-matter, or method-of-use patent.

How are the independent claims structured?

The patent has three principal independent claims: claims 1, 20, and 37.

Independent claim	Core subject matter	Main concentration limitation	Required process or composition
Claim 1	Solid dosage form with porous matrix	Matrix composition from about 0.1% to 7.5% by weight of dispersion	Lyophilization or solid-state dissolution
Claim 20	Solid dosage form with porous matrix	Matrix composition from about 0.1% to 15% by weight of solution	Lyophilization or solid-state dissolution
Claim 37	Solid dosage form with gelatin and amino acid	No concentration in the independent claim	Porous matrix containing gelatin and amino acid

Claims 1 and 20 are process-defined formulation claims. They require the dosage form to have been prepared from a matrix composition dispersion or solution subjected to lyophilization or solid-state dissolution.

Claim 37 is broader in one respect because it focuses on the final porous matrix composition and does not place the process limitation directly in the independent claim. Its required composition is narrower: gelatin plus one or more amino acids having 2 to 12 carbon atoms.

What elements must be present to infringe claim 1?

A product would need to satisfy all material limitations of claim 1. The principal elements are:

A solid dosage form.
A porous network of a matrix composition.
A matrix that disperses rapidly in water.
A matrix composition dispersion containing approximately 0.1% to 7.5% matrix composition by weight.
Preparation by lyophilization or solid-state dissolution.
A matrix-forming agent.
One or more amino acids containing approximately 2 to 12 carbon atoms.

The active ingredient is not required by claim 1. A placebo or nutraceutical formulation could fall within the claim if the remaining limitations were met.

The claim does not require glycine, gelatin, or mannitol. Those features appear in dependent claim 2 and claim 3. Claim 1 therefore reaches a wider genus of amino-acid-containing porous matrices, subject to the process and concentration limitations.

What amino acids and excipients are covered?

Amino acids

The amino-acid limitation is defined by carbon number rather than by a closed list of named amino acids. Glycine is expressly claimed, but the claim language can encompass other amino acids with 2 to 12 carbon atoms, depending on their chemical structure and whether they satisfy the applicable claim-construction requirements.

Representative candidates may include:

Glycine.
Alanine.
Valine.
Leucine.
Isoleucine.
Serine.
Threonine.
Aspartic acid.
Glutamic acid.
Phenylalanine.
Other amino acids within the stated carbon range.

The carbon-count limitation is important. A formulation containing an amino acid outside the claimed range may avoid literal infringement of the amino-acid limitation, although other claims, equivalents, or related patents could remain relevant.

Matrix-forming agents

Claim 3 identifies gelatin, mannitol, and mixtures thereof. Claims 37 and its dependents place particular emphasis on gelatin.

The claim architecture creates several tiers of protection:

Claim 1: matrix-forming agent plus amino acid.
Claim 3: gelatin, mannitol, or a mixture.
Claim 37: gelatin plus amino acid.
Claim 39: gelatin plus amino acid plus mannitol.
Claim 40: addition of xanthan gum.
Claims 48 to 50: defined concentration ranges for gelatin, amino acid, and mannitol.

A formulation using a polymeric matrix former other than gelatin, with no mannitol, may fall outside the narrower dependent claims but could still be evaluated against claim 1.

What manufacturing methods are protected?

The patent covers two principal manufacturing routes.

Lyophilization

Lyophilization, or freeze-drying, is expressly recited in claims 1, 5, 20, 24, 37, 42, and 46. The process generally involves:

Preparing a solution, suspension, emulsion, or other dispersion.
Incorporating the matrix components and, where applicable, the active ingredient.
Freezing the composition.
Removing solvent under reduced pressure.
Producing a porous solid matrix.

The process limitation may provide a meaningful design-around path for products made by conventional compression, molding, spray drying, or other non-lyophilization methods. That analysis depends on whether the final product nevertheless falls within claim 37 or another applicable claim.

Solid-state dissolution

The claims also recite solid-state dissolution. This language is less conventional than standard aqueous solution processing and should be read with the specification and prosecution history. A product made through a process that does not meet the patent's technical meaning of solid-state dissolution may avoid claims requiring that process.

Solution, emulsion, or suspension

Claims 17, 18, 19, 55, 56, and 57 expressly cover matrix dispersions that are solutions, emulsions, or suspensions. These dependent claims prevent a design-around based solely on changing the initial physical form of the matrix preparation.

What formulation features are protected?

Feature	Relevant claims	Scope
Glycine	2, 21, 38	Expressly claimed amino acid
Gelatin	3, 22, 37, 48	Matrix-forming agent and core claim-37 component
Mannitol	3, 13, 22, 32, 39, 50	Matrix former or additional excipient
Xanthan gum	4, 23, 40	Optional matrix additive
Cyclodextrin	14, 33, 51	Optional solubilizing or complexing excipient
Magnesium trisilicate	14, 33, 51	Optional inorganic excipient
Magnesium aluminum silicate	14, 33, 51	Optional inorganic excipient
Gas or foam	8, 27, 45	Aerated porous dosage form
Hydrophobic coating	9, 10, 28, 29, 46, 47	Coated active particles
Fast dispersion	15, 34, 52	Less than approximately 10 seconds

The coated-particle claims are commercially important because they address a common technical problem in fast-dissolving dosage forms: exposure of a taste-masked or hydrophobic-coated active during manufacture and rapid dispersion.

Claims 10, 29, and 47 identify fatty acids, glycerides, triglycerides, and mixtures as coating materials. A product using a different coating chemistry may avoid those narrow claims while remaining subject to broader active-agent or matrix claims.

How broad are the concentration limitations?

The patent contains overlapping concentration ranges.

Claim group	Matrix concentration	Other concentration limits
Claims 1, 16	About 0.1% to 7.5%; claim 16 narrows to 0.1% to 4%	None in independent claim
Claims 11 to 13	Matrix former about 0.1% to 3%; amino acid at least 0.5%; mannitol at least 0.5%	Dependent limitations
Claims 20, 35, 36	About 0.1% to 15%; narrower alternatives to 7.5% and 4%	Solution-based embodiment
Claims 30 to 32	Matrix former about 0.1% to 3%; amino acid and mannitol about 0.5% to 10%	Solution embodiment
Claims 41, 53, 54	About 0.1% to 15%; narrower alternatives to 7.5% and 4%	Gelatin-based embodiment
Claims 48 to 50	Gelatin about 0.1% to 3%; amino acid and mannitol about 0.5% to 10%	Gelatin claim family

The percentages are stated by weight of the dispersion or solution. That basis matters. A formulation may have a different percentage after freezing, drying, or removal of water. In an infringement analysis, the relevant point is generally the composition before processing if the claim defines concentration in the initial dispersion or solution.

What FDA regulatory status and Orange Book issues apply?

US 5,648,093 does not appear, from the claim set, to be directed to a named active ingredient or approved drug product. It is therefore not the type of patent ordinarily listed in the FDA Orange Book as a drug-substance, drug-product, or method-of-use patent for a particular NDA.

Regulatory issue	Assessment
Drug-specific patent	No
Active ingredient identified	No
Indication identified	No
Dosage strength identified	No
Orange Book listing	No product-specific listing can be inferred from these claims
Paragraph IV relevance	Product-specific only, if a listed NDA relied on this patent
Biosimilar relevance	Low; this is a small-molecule dosage-form technology patent
Generic formulation relevance	Historically high, because the claims cover dosage-form architecture

A generic applicant would ordinarily address this patent only if it were listed for the reference product or asserted in litigation. A standalone expired platform patent would not independently create a current ANDA barrier or a Paragraph IV filing requirement.

When did US 5,648,093 lose exclusivity?

US 5,648,093 issued on July 15, 1997. For a pre-June 8, 1995 US application, the transitional patent-term rules generally provide the longer of 17 years from grant or 20 years from the earliest effective US nonprovisional filing date, subject to adjustments.

Using the issue-based term, the patent expired July 15, 2014, absent an unusual term adjustment or other statutory extension. No patent-term extension under Hatch-Waxman is indicated by the platform formulation claims. The patent is therefore expired and cannot support a current US infringement action.

Event	Date or status
US patent issued	July 15, 1997
Standard 17-year issue term	July 15, 2014
Current enforceability	Expired
Patent-term extension	None indicated
Regulatory exclusivity	No drug-specific exclusivity shown

Expiration does not remove the patent from the prior-art record. It can still affect validity analysis of later patents claiming similar lyophilized matrices, amino-acid excipients, coated particles, or rapidly dispersing dosage forms.

How does US 5,648,093 compare with competing fast-dissolving dosage-form patents?

US 5,648,093 sits within the broader orally disintegrating and fast-dissolving dosage-form field. Representative earlier and related technologies include:

Technology area	Typical claim focus	Relationship to US 5,648,093
Early lyophilized dosage forms	Porous freeze-dried units	Technical predecessor and overlapping platform
Zydis-type systems	Freeze-dried, rapidly dissolving dosage forms	Similar dosage-form objective; claim overlap depends on matrix and process limitations
Compressed orally disintegrating tablets	Compression, superdisintegrants, porous excipients	Potentially outside claims requiring lyophilization or solid-state dissolution
Taste-masked particles	Coated drug particles in rapidly dispersing matrices	Addressed directly by claims 9, 10, 28, 29, 46, and 47
Foam or aerated systems	Gas-containing porous matrices	Addressed by claims 8, 27, and 45
Later formulation patents	Specific excipient ratios, active ingredients, or manufacturing parameters	May have developed around the broad platform claims

The strongest historical coverage is in the combination of low-solids matrix processing, amino-acid inclusion, porous structure, and rapid aqueous dispersion. The weakest practical coverage is against conventional compressed tablets that do not use the claimed preparation route and do not contain the claimed gelatin-amino-acid matrix.

What generic launch risks exist today?

US 5,648,093 presents no current US generic-launch risk because its patent term has expired. Historical risk would have varied by product design.

Higher historical risk

A product would have presented greater exposure if it used:

A freeze-dried porous dosage form.
Gelatin and glycine.
Mannitol in the claimed concentration ranges.
A matrix dispersion within the recited solids ranges.
Hydrophobically coated active particles.
A dispersion time below approximately 10 seconds.
An aerated or foam matrix.

Lower historical risk

Exposure would generally have been lower for:

Conventional compressed tablets.
Nonporous dosage forms.
Formulations without amino acids in the 2-to-12-carbon range.
Products made without lyophilization or solid-state dissolution.
Products using alternative matrix systems outside the claim language.
Products with different concentration bases or ranges.

These distinctions would have mattered during the patent term. They have no current blocking effect in the United States because the patent is expired.

Which companies and products were historically relevant?

The relevant commercial field included developers and manufacturers of orally disintegrating, freeze-dried, and taste-masked dosage forms. R.P. Scherer, later associated with Catalent's pharmaceutical technology businesses, was a major developer of freeze-dried fast-dissolving dosage technologies. Other companies developed compressed orally disintegrating tablets, coated microparticles, and alternative porous delivery systems.

The patent itself does not establish ownership of any particular marketed drug, licensing arrangement, or product revenue stream. No active ingredient appears in the claims. Revenue exposure therefore cannot be calculated from this patent alone. Any commercial assessment must be tied to a specific NDA, product, license, or litigation record.

What is the current patent strength of US 5,648,093?

Factor	Assessment
Claim breadth during term	Moderate to broad for the specified platform
Composition coverage	Broad in claims 1 and 20; narrower but potentially stronger in claim 37
Process dependence	Significant for claims 1 and 20
Active-ingredient dependence	None
Design-around potential	Meaningful through process, matrix, amino-acid, and concentration changes
Current enforceability	None because the patent is expired
Prior-art significance	Potentially material against later fast-dissolving matrix patents
Biosimilar significance	Minimal
Orange Book significance	No product-specific significance apparent

Claim 37 was likely the most important claim from a claim-scope perspective because it does not expressly require the lyophilization or solid-state dissolution step in the independent claim. Its reach is constrained by the requirement for gelatin and an amino acid in a porous, rapidly water-dispersible matrix.

Key Takeaways

US 5,648,093 covers fast-dispersing porous solid dosage forms containing amino acids and matrix-forming materials.
The principal claimed excipients are gelatin, mannitol, glycine, and related matrix components.
Claims 1 and 20 depend heavily on lyophilization or solid-state dissolution and specified initial composition ranges.
Claim 37 focuses on a porous gelatin-amino-acid matrix and is structurally broader regarding manufacturing process.
Dependent claims cover foam dosage forms, coated active particles, hydrophobic coatings, xanthan gum, cyclodextrins, and inorganic silicates.
The patent is not directed to a specific active ingredient, therapeutic indication, or NDA product.
The patent issued July 15, 1997, and its standard term expired July 15, 2014.
It does not present a current US patent barrier to generic entry.
Its main continuing relevance is as prior art and as a historical platform patent in orally disintegrating and lyophilized dosage forms.
No Paragraph IV, Orange Book, biosimilar, licensing, or current litigation conclusion can be derived from the claims alone.

FAQs

Does US 5,648,093 cover orally disintegrating tablets?

It covers a subset of fast-dispersing solid dosage forms, particularly porous matrices prepared by lyophilization or solid-state dissolution. A conventional compressed orally disintegrating tablet may fall outside the principal claims.

Does the patent require glycine?

No. Glycine is expressly claimed in dependent claims, but the independent claims generally require one or more amino acids with approximately 2 to 12 carbon atoms.

Can a formulation avoid the patent by replacing gelatin with another polymer?

That may avoid the gelatin-specific claims, including claim 37 and related dependents. It would not automatically avoid claim 1 if the substitute is a matrix-forming agent and all other limitations are met.

Does the patent cover taste-masked drug particles?

Yes, claims 9, 10, 28, 29, 46, and 47 address particulate active ingredients coated with agents, including hydrophobic fatty acids, glycerides, and triglycerides.

Is US 5,648,093 relevant to biosimilar litigation?

Generally no. The patent claims a small-molecule dosage-form platform and does not claim a biologic, biosimilar, biological manufacturing process, or therapeutic protein.

References

United States Patent and Trademark Office. (1997). U.S. Patent No. 5,648,093, Fast-dissolving solid dosage forms. https://patents.google.com/patent/US5648093
United States Patent and Trademark Office. (n.d.). Patent term calculator and patent term information. https://www.uspto.gov/patents/laws/patent-term-calculator
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book
U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application process. https://www.fda.gov/drugs/types-applications/abbreviated-new-drug-application-anda
United States Patent and Trademark Office. (n.d.). Patent litigation case information and Patent Trial and Appeal Board resources. https://www.uspto.gov/patents-application-process/appealing-patent-decisions.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	177006	⤷ Start Trial
Austria	183387	⤷ Start Trial
Australia	4232293	⤷ Start Trial
Australia	646428	⤷ Start Trial
Australia	677198	⤷ Start Trial
Australia	7171191	⤷ Start Trial
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Details for Patent: 5,648,093

Summary for Patent: 5,648,093