United States Patent 6,509,038: Itraconazole Solid-Dispersion Claims, Scope, Expiration, and Patent Landscape

U.S. Patent No. 6,509,038 protected a narrowly defined itraconazole tablet containing sub-600-micron solid-dispersion particles, HPMC of specified viscosity, and a detailed excipient composition. Its dependent method claims covered once-daily administration and administration without regard to food. The patent is expired, so it does not currently block generic manufacture or sale in the United States. Its principal commercial significance was historical: it supported the food-independent, once-daily positioning of an itraconazole tablet formulation associated with Sporanox.

What does U.S. Patent 6,509,038 protect?

The patent protects three related subject matters:

A specific pharmaceutical dosage form.
Oral treatment of fungal infection with that dosage form once daily.
Administration independently of the patient’s food intake.

The claims do not cover itraconazole generally, every itraconazole formulation, or every solid dispersion. Claim 1 requires a combination of particle structure, polymer characteristics, particle size, and tablet composition.

What is the scope of independent claim 1?

Claim 1 contains several cumulative limitations:

Limitation	Required feature
Active ingredient	Itraconazole, specified stereoisomers, or mixtures of two, three, or four stereoisomers
Particle composition	Particles consisting of a solid dispersion of itraconazole and one or more water-soluble polymers
Particle size	Less than 600 micrometers
Solid-dispersion structure	A solid solution, or a dispersion involving amorphous or microcrystalline material in a solid solution
Polymer viscosity	Apparent viscosity of 1 to 100 mPa.s in a 2% aqueous solution at 20°C
Tablet core	Exact listed itraconazole, HPMC, lactose/MCC, crospovidone, talc, hydrogenated vegetable oil, silica, and magnesium stearate quantities
Film coat	Exact listed HPMC, propylene glycol, talc, and titanium dioxide quantities

The formulation is substantially narrower than the opening language suggests because the claim then specifies a detailed tablet recipe. The claimed tablet core is:

Component	Weight percentage of total dosage form
Itraconazole	21.65%
HPMC 2910, 5 mPa.s	32.48%
Spray-dried lactose monohydrate:MCC, 75:25	30.57%
Crospovidone	8.49%
Talc	2.79%
Hydrogenated vegetable oil Type I	0.93%
Colloidal anhydrous silica	0.28%
Magnesium stearate	0.24%
Tablet core subtotal	97.43%
HPMC 2910, 5 mPa.s in coating	1.47%
Propylene glycol	0.37%
Talc in coating	0.29%
Titanium dioxide	0.44%
Film coat subtotal	2.57%

The percentages total 100%. That strongly indicates a formulation claim directed to the disclosed commercial-style tablet rather than a broad Markush claim covering any itraconazole solid dispersion.

How does “comprising” affect infringement analysis?

The preamble uses “comprising,” which normally makes the dosage-form claim open-ended. An accused product could contain additional ingredients and still potentially fall within the claim. That does not eliminate the separate requirement to meet the listed quantitative limitations.

The critical issue is whether the listed weight percentages are exact limitations or should be construed with ordinary manufacturing tolerances. A formulation materially departing from the percentages, polymer grade, or coating composition would have a substantial non-infringement position. A product containing the same ingredients but using different proportions would not automatically infringe.

The phrase “particles consisting of” is narrower than “comprising.” It can exclude additional particle constituents, depending on how the particle is characterized. Excipients added outside the solid-dispersion particles would not necessarily defeat the claim because claim 1 separately describes the broader dosage form.

What solid-dispersion technology is protected?

The technical center of the patent is an itraconazole solid dispersion using a water-soluble polymer, particularly low-viscosity HPMC 2910.

Itraconazole has poor aqueous solubility. The claimed solid-dispersion structure addresses dissolution and bioavailability by placing itraconazole in a polymeric matrix in which the drug can exist as a solid solution or as amorphous or microcrystalline material dispersed through the matrix.

What polymer limitations apply?

The polymer must be water-soluble and must have an apparent viscosity of 1 to 100 mPa.s when measured in a 2% aqueous solution at 20°C. The disclosed tablet uses HPMC 2910 with a nominal viscosity of 5 mPa.s.

This limitation has two consequences:

A formulation using a different polymer may fall outside the literal claim even if it produces the same dissolution result.
HPMC of a materially different viscosity grade may create a non-infringement position, subject to equivalence analysis.

The claim does not cover every HPMC grade. It identifies a viscosity range and a particular 5 mPa.s HPMC grade in the detailed formulation.

Why is the 600-micrometer particle-size limitation important?

The particles must have a size of less than 600 μm. This is a physical limitation that can create disputes over:

The measurement method.
Whether the limitation applies to all particles or an average particle size.
The sampling method.
Whether agglomerates are included.
Whether the relevant material is the solid-dispersion intermediate or the final tablet blend.

A generic manufacturer using a different granulation or milling process would need to assess particle-size distribution data, not merely the nominal manufacturing target.

What do claims 2 and 3 protect?

Claim 2 depends on claim 1. It requires oral administration of the claimed dosage form to treat a fungal infection in a mammal, with itraconazole administered once daily.

Claim 3 depends on claim 2 and adds administration at any time of day independently of food intake.

These claims are narrower than an independent method claim because every limitation of claim 1 carries into the method. A party could avoid claims 2 and 3 by using a different itraconazole dosage form, even if the treatment regimen and food instructions were identical.

Does claim 3 cover all food-independent itraconazole use?

No. Claim 3 is tied to the dosage form of claim 1. It does not independently monopolize the clinical instruction to take itraconazole without food. The accused product must first satisfy the formulation limitations in claim 1.

The claim also uses “can be administered,” which may raise questions about whether the limitation concerns the product’s demonstrated pharmacokinetic performance, labeling, intended use, or a method of administration. In an ANDA context, the approved label and proposed labeling would be central to any induced-infringement analysis.

When did U.S. Patent 6,509,038 lose exclusivity?

U.S. Patent 6,509,038 is expired and no longer provides enforceable patent exclusivity in the United States.

Item	Detail
Patent	U.S. 6,509,038
Technology	Itraconazole solid-dispersion dosage form
Patent type	Utility patent
Assignee associated with the patent	Janssen Pharmaceutica N.V.
Grant date	January 21, 2003
Statutory framework	20-year term measured from the effective U.S. nonprovisional filing date, subject to applicable adjustments
Current status	Expired
Current blocking effect	None from this patent alone

The patent’s enforceable term ended years ago under the U.S. patent-term framework. Any patent-term adjustment or patent-term extension would have been reflected in the official USPTO and FDA records. The patent’s expiration does not revive other patents in the itraconazole portfolio.

What is the Orange Book status of U.S. Patent 6,509,038?

The Orange Book analysis must distinguish between:

Patents listed against the relevant NDA.
Patents that once covered a commercial product.
Patents that remain unexpired.
Patents that cover the exact dosage form and labeling.

The FDA Orange Book lists patents and exclusivity associated with approved drug products, but an expired patent does not create a current barrier to ANDA approval or commercial launch. A patent number can remain historically relevant even after its term has ended.

For itraconazole, the principal regulatory products have included capsule and oral-solution products associated with Sporanox, while later products used different formulation technologies. The relevance of U.S. 6,509,038 depends on whether the NDA and dosage form at issue corresponded to the patented tablet formulation. An Orange Book listing would not expand the patent’s claims beyond their language.

Which companies challenged or competed against the itraconazole estate?

Generic competition developed primarily around itraconazole capsules and oral solution. The competitive field has included generic-drug manufacturers supplying conventional itraconazole dosage forms and specialty manufacturers developing improved bioavailability formulations.

The main categories are:

Product category	Competitive position
Conventional itraconazole capsules	Generic competition after relevant formulation and regulatory barriers expired
Itraconazole oral solution	Separate dosage form with different formulation and labeling considerations
Sporanox capsules and solution	Janssen-originated products
SUBA-itraconazole/Tolsura	Improved absorption formulation associated with Mayne Pharma
Other solid dispersions	Potentially distinct from the exact HPMC/tablet composition in U.S. 6,509,038

The later SUBA-itraconazole product is particularly important because it uses a different formulation platform and has its own regulatory and patent history. A competitor cannot assume that expiration of U.S. 6,509,038 eliminates all patent risk associated with improved itraconazole formulations.

What formulation patents followed U.S. 6,509,038?

Later itraconazole patents have generally focused on improved bioavailability, reduced food dependence, multiparticulate delivery, amorphous dispersions, and alternative excipient systems.

A frequently cited later patent family is associated with itraconazole compositions and methods developed for SUBA-itraconazole. U.S. Patent No. 9,192,644 is an example of a later itraconazole formulation patent associated with that technology. Its claims and expiration must be assessed independently from U.S. 6,509,038. The two patents should not be treated as a single estate merely because both concern itraconazole solid dispersions.

How does the older patent compare with later SUBA-itraconazole patents?

Issue	U.S. 6,509,038	Later improved-bioavailability patents
Product focus	Specific tablet composition	Alternative formulation platforms
Polymer limitation	Water-soluble polymer, 1-100 mPa.s viscosity	May use different carriers, ratios, or processing
Particle size	Less than 600 μm	May use different particle or dispersion specifications
Food independence	Express method claim	Often supported through pharmacokinetic and labeling claims
Current term	Expired	Some later patents may have remained in force depending on family and adjustment
Generic risk	No current risk from this patent	Product-specific risk remains possible

Are there Paragraph IV risks associated with this patent?

There is no current Paragraph IV risk from U.S. 6,509,038 because the patent is expired. A Paragraph IV certification is relevant when an ANDA applicant asserts that a listed patent is invalid, unenforceable, or will not be infringed. An expired patent cannot block approval or launch based on remaining patent term.

Historically, an ANDA applicant targeting a product covered by the patent could have faced:

A Paragraph IV notice.
A 45-day period for the patent holder to file suit.
A 30-month stay of approval under the Hatch-Waxman framework, subject to statutory exceptions.
Potential settlement restrictions or a first-filer position.

Those consequences are historical for this patent. Current ANDA strategy must focus on any unexpired patents listed for the specific reference product, including later formulation patents.

What generic launch scenarios exist?

The expiration of U.S. 6,509,038 supports several launch scenarios:

A conventional itraconazole capsule or solution can launch if no unexpired patents or regulatory exclusivities block the targeted product.
A tablet using a different polymer, excipient ratio, or dispersion process can avoid the expired claim set independently of patent expiration.
A product seeking to substitute for SUBA-itraconazole may face separate patents and may require a different regulatory pathway than a conventional itraconazole ANDA.
A formulation using the exact historical composition faces no live restriction from U.S. 6,509,038, but manufacturing know-how, analytical specifications, and product-specific patents may still matter.

The practical commercial distinction is between generic itraconazole and an authorized or substitutable version of a later improved-bioavailability product.

How strong was the patent estate?

The patent was technically meaningful but claim-scope limited.

Strengths

It linked itraconazole solid dispersion to a specific dosage form.
It included measurable particle-size and polymer-viscosity requirements.
It supported a once-daily, food-independent administration position.
The detailed formulation could be commercially relevant if it matched the marketed tablet.

Weaknesses

The exact quantitative formulation requirements narrowed literal infringement.
The method claims depended on the full formulation claim.
Alternative polymers, particle-size distributions, excipients, and manufacturing processes could avoid the claims.
The patent is expired.
It did not cover all itraconazole products or all amorphous solid dispersions.

The patent had stronger historical value as a product-specific formulation patent than as a broad platform patent.

What manufacturing and IP barriers remain?

The expired patent removes one legal barrier, but development barriers remain:

Achieving consistent itraconazole amorphous content.
Controlling recrystallization during storage.
Reproducing dissolution across batches.
Managing particle-size distribution.
Demonstrating bioequivalence for the selected dosage form.
Controlling HPMC grade and viscosity.
Establishing stability under commercial packaging conditions.
Avoiding later formulation patents and trade secrets.

For a generic developer, the highest-risk issues are likely to be product-specific regulatory requirements and later active patents, not U.S. 6,509,038 itself.

What is the patent litigation status?

U.S. 6,509,038 has no current litigation significance as an enforceable patent because its term has ended. Historical litigation, if any, would need to be separated from current infringement exposure. A later lawsuit involving itraconazole, SUBA-itraconazole, or another formulation should not be attributed to U.S. 6,509,038 without matching the asserted patent number and claims.

Key Takeaways

U.S. 6,509,038 claimed a narrow itraconazole tablet formulation, not itraconazole generally.
Claim 1 required a sub-600-micron solid dispersion, a water-soluble polymer within a defined viscosity range, and a detailed composition.
HPMC 2910 at 5 mPa.s was central to the disclosed formulation.
Claims 2 and 3 depended on the full formulation limitations and added once-daily and food-independent administration.
The patent is expired and creates no current U.S. exclusivity.
Generic itraconazole capsules and oral solutions must be analyzed separately from improved-bioavailability products.
Later itraconazole formulation patents, including patents associated with SUBA-itraconazole, may present distinct patent risks.
The strongest historical value of U.S. 6,509,038 was its alignment with a specific commercial tablet and food-independent dosing profile.

FAQs About U.S. Patent 6,509,038

Does U.S. Patent 6,509,038 cover itraconazole capsules?

No. The claims are directed to a dosage form containing the specified solid-dispersion particles and detailed tablet composition. Conventional capsules are not automatically covered.

Can a generic manufacturer use HPMC in an itraconazole product?

Yes. Expiration of U.S. 6,509,038 removes the patent barrier from that patent. A developer must still assess later patents, regulatory requirements, and whether the product targets a different protected reference product.

Does the patent cover a once-daily itraconazole regimen by itself?

No. Once-daily treatment appears in claim 2, which depends on claim 1. The regimen is not claimed independently from the specific dosage form.

Is food-independent itraconazole administration still commercially important?

Yes. Food effects can influence itraconazole exposure and labeling. The commercial value of food-independent dosing may remain relevant even though the patent claim protecting that feature has expired.

Are biosimilar rules relevant to itraconazole?

No. Itraconazole is a small-molecule drug. Generic-drug and ANDA rules apply, rather than the biosimilar pathway under the Public Health Service Act.

References

U.S. Patent No. 6,509,038. (2003). Pharmaceutical dosage form comprising itraconazole. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations (Orange Book). FDA.
U.S. Food and Drug Administration. (2024). Drugs@FDA: FDA-approved drugs. FDA.
United States Patent and Trademark Office. (2024). Patent term adjustment and patent term extension. USPTO.
U.S. Patent No. 9,192,644. (2015). Itraconazole compositions and methods of use thereof. United States Patent and Trademark Office.
Drug Price Competition and Patent Term Restoration Act, 21 U.S.C. §§ 355, 156.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
	96201430	May 20, 1996
	97200698	Mar 07, 1997

PCT Information
PCT Filed	May 12, 1997	PCT Application Number:	PCT/EP97/02507
PCT Publication Date:	November 27, 1997	PCT Publication Number:	WO97/44014

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	007195	⤷ Start Trial
Austria	255883	⤷ Start Trial
Australia	2956297	⤷ Start Trial
Australia	722101	⤷ Start Trial
Bulgaria	102532	⤷ Start Trial
Bulgaria	64368	⤷ Start Trial
Brazil	9706897	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,509,038

Summary for Patent: 6,509,038