United States Patent 8,273,876: Vardenafil Coated-Tablet Process, Claim Scope and Generic-Entry Landscape
U.S. Patent No. 8,273,876 protects a manufacturing process that converts vardenafil hydrochloride in a tablet into vardenafil hydrochloride trihydrate by controlled exposure to humid gas. The patent does not broadly claim vardenafil, Levitra, or every tablet containing vardenafil. Its commercial reach depends on whether a competing product is made using the claimed humidity-conversion process and whether the patent remains listed and enforceable against the relevant product.
The two independent process claims cover opposite manufacturing sequences:
- Humidification, followed by coating, under claim 1.
- Coating, followed by humidification, under claim 12.
The patent's nominal term extends into 2027 based on its priority and filing chronology, subject to the official USPTO term calculation and any applicable adjustments.[1]
What does U.S. Patent 8,273,876 cover?
The patent covers production of coated tablets containing vardenafil hydrochloride trihydrate. The essential process is controlled solid-state conversion of vardenafil hydrochloride into the trihydrate form before or after application of the tablet coating.
| Claim element |
Claim 1 |
Claim 12 |
| Starting tablet contains vardenafil hydrochloride |
Required |
Required |
| Initial polymorphic form can be any form or mixture |
Required |
Required |
| One or more excipients |
Required |
Required |
| Disintegrant present |
Required |
Required |
| Exposure to moistened gas |
Required |
Required |
| At least 90 mol% conversion to trihydrate |
Required |
Required |
| Coating applied |
Required |
Required |
| Sequence |
Humidification, then coating |
Coating, then humidification |
The claims are process claims. They do not claim a composition merely because it contains vardenafil hydrochloride trihydrate. A competitor would face a stronger infringement case if its manufacturing records, batch instructions, validation documents, or regulatory filings show the claimed humidity treatment.
How strong are the independent claims?
Claims 1 and 12 are commercially significant because they capture both logical process sequences used to produce a coated tablet.
Claim 1: humidification before coating
Claim 1 requires:
- a tablet containing vardenafil hydrochloride;
- any initial polymorphic form or mixture of forms;
- at least one excipient, including a disintegrant;
- treatment with a moistened gas;
- conversion of at least 90 mol% of the active ingredient to the trihydrate;
- subsequent coating.
The phrase covering “irrespective of which polymorphic form or mixture of polymorphic forms” broadens the starting-material limitation. A process cannot readily avoid claim 1 merely by using a different initial polymorph if the tablet is later humidified and reaches the 90 mol% conversion threshold.
Claim 12: coating before humidification
Claim 12 contains the same core limitations but reverses the order:
- Make the tablet.
- Apply the coating.
- Expose the coated tablet to moistened gas.
- Convert at least 90 mol% of the vardenafil hydrochloride to the trihydrate.
This claim is important because the coating may affect water penetration, solid-state conversion, dissolution, and stability. A process that avoids claim 1 by coating before humidity treatment may still fall within claim 12.
What limitations do the dependent claims add?
The dependent claims narrow the process but also identify the operating conditions most likely to be relevant in commercial manufacturing.
| Claims |
Limitation |
| 2, 13 |
Air is the moistened gas |
| 3, 14 |
Relative humidity of 35% to 100% |
| 6 |
Relative humidity of 50% to 99% |
| 7 |
Treatment time of 0.5 hours to 6 months |
| 8 |
Treatment temperature of 16°C to 30°C |
| 9, 17 |
Disintegrant is microcrystalline cellulose, crospovidone, or both |
| 10, 18 |
Coating agent is hypromellose, macrogol, or both |
| 11, 19 |
Combination of specified disintegrant and coating agent |
Claims 11 and 19 are the most formulation-specific dependent claims. They require both:
- a disintegrant selected from microcrystalline cellulose and crospovidone; and
- a coating agent selected from hypromellose and macrogol.
A generic manufacturer using other excipients might avoid those dependent claims while still infringing claim 1 or claim 12.
What products and dosage forms are within the patent's scope?
The claims are directed to coated tablets. They do not expressly cover:
- uncoated tablets;
- capsules;
- orally disintegrating tablets;
- films;
- granules;
- liquid formulations;
- injectable products;
- transdermal systems.
The tablet must contain vardenafil hydrochloride during the claimed process. A process beginning with a different vardenafil salt, free base, solvate, or chemically modified derivative would require separate analysis because the claim language specifically refers to vardenafil hydrochloride.
The resulting product must contain at least 90 mol% vardenafil hydrochloride trihydrate. The patent therefore has a measurable analytical limitation. X-ray powder diffraction, thermal analysis, water-content testing, and solid-state characterization could be relevant to proving or disputing compliance with the conversion threshold.
What does the 90 mol% conversion requirement mean?
The 90 mol% threshold is a central limitation. The process is not satisfied merely because trihydrate is present. At least 90 mol% of the vardenafil hydrochloride must be converted into the trihydrate form.
This creates both infringement and validity issues:
- The patentee may need reliable analytical evidence showing conversion above 90 mol%.
- A competitor may argue that its process produces a lower proportion of trihydrate.
- Batch-to-batch variation may affect infringement analysis.
- Regulatory specifications and stability data may indirectly reveal whether the threshold is met.
- The claim does not require 100% conversion.
A process that intentionally produces a stable mixture below the 90 mol% threshold could present a potential design-around, although it may create separate product-quality, dissolution, or regulatory problems.
What manufacturing conditions are protected?
The broadest independent claims do not expressly require air, a particular relative humidity, a temperature, or a treatment duration. Those limitations appear in dependent claims.
The dependent operating window includes:
| Parameter |
Claimed range |
| Gas |
Air |
| Relative humidity |
35% to 100% |
| Narrower humidity range |
50% to 99% |
| Temperature |
16°C to 30°C |
| Treatment duration |
0.5 hours to 6 months |
The broad treatment-duration range is unusual because it reaches from a half hour to six months. It may cover both accelerated manufacturing operations and extended conditioning or storage processes, depending on how the claims and specification are interpreted.
A competitor using nitrogen, oxygen-enriched air, steam, or another humidified gas could avoid claims 2 and 13 if the process does not use air, but it may still face claims 1 and 12. Similarly, a process outside the dependent humidity or temperature ranges could remain within the independent claims.
What are the treatment-method claims?
Claims 4 and 5 depend on the product made under claim 1. Claims 15 and 16 depend on the product made under claim 12.
They cover administration of the resulting coated tablet for:
- erectile dysfunction; and
- sexual dysfunctions.
These claims are narrower than ordinary composition or method-of-treatment claims because they require the administered tablet to have been made by the specified manufacturing process.
The treatment claims may have limited practical value against a generic manufacturer unless the patentee can connect the administered product to the patented process. They may be more relevant in an ANDA context, where manufacturing information, product descriptions, patent certifications, and regulatory submissions can provide evidence about the proposed process.
When does U.S. Patent 8,273,876 lose exclusivity?
The patent was granted on September 25, 2012.[1] Its priority and international filing history place the nominal expiration in 2027, subject to the official patent-term calculation.
| Event |
Date or period |
| Earliest priority |
2006, based on the published patent family record |
| U.S. grant |
September 25, 2012 |
| Nominal expiration |
2027, approximately 20 years from the applicable earliest nonprovisional/PCT filing |
| Patent-term adjustment |
Must be confirmed from USPTO records |
| Patent-term extension |
No extension should be assumed without an FDA and USPTO determination |
Patent expiration is separate from FDA regulatory exclusivity. A patent may expire after FDA exclusivity has ended, and an ANDA applicant may challenge the patent before expiration through a Paragraph IV certification.
What is the Orange Book status of U.S. Patent 8,273,876?
The relevant regulatory question is whether Bayer listed the patent for an approved vardenafil hydrochloride product, including Levitra or an associated NDA, and whether the listing remained active for the dosage forms and uses covered by the approved application.
Orange Book listings can affect ANDA timing through:
- Paragraph IV certification;
- a 45-day period for the NDA holder or patent owner to file suit;
- a potential 30-month stay of approval under the Hatch-Waxman framework;
- 180-day first-applicant exclusivity in appropriate circumstances.
The Orange Book does not determine infringement. Listing is an FDA administrative event, while claim scope and infringement are judicial questions. A listed process patent can still create substantial launch risk if the ANDA's proposed manufacturing process falls within the claims.
The patent should be reviewed against the current Orange Book patent table for the applicable vardenafil NDA. Listing status, use codes, delisting, and any expiration-date corrections can change over time.[2]
Which companies challenged Levitra and vardenafil patents?
Vardenafil generic competition arose through the ANDA pathway after the primary Levitra exclusivity period and key substance-patent barriers diminished. Known commercial generic activity has included major generic manufacturers such as Teva and other ANDA applicants.
The relevant challenge structure is usually:
- The ANDA applicant files a Paragraph IV certification.
- Bayer and related patent owners evaluate the listed patents.
- Litigation may follow in the U.S. District Court for the District of Delaware or another appropriate venue.
- Settlement terms may establish a licensed entry date before patent expiration.
- FDA approval may occur before commercial launch if the settlement permits delayed entry.
The existence of an approved generic does not by itself establish that U.S. Patent 8,273,876 was invalidated, disclaimed, expired early, or settled. Generic approval can reflect a non-infringement position, a license, a settlement, a patent not listed for the relevant application, or a process outside the patent's claims.
What patent litigation and settlement issues affect generic entry?
For this patent, the core litigation issues would likely include:
Infringement
The patentee would need to establish that the accused manufacturing process includes:
- a vardenafil hydrochloride tablet;
- a disintegrant;
- humid-gas treatment;
- conversion of at least 90 mol% to trihydrate;
- coating before or after treatment, depending on the asserted independent claim.
Claim construction
Potential disputes include:
- whether “treating” requires intentional process conditioning;
- how “sufficient time” is measured;
- how the 90 mol% conversion threshold is established;
- whether the coating step must occur on the same tablet batch;
- whether the claimed excipient requirement is satisfied by a minor amount of disintegrant.
Validity
Potential prior-art issues include:
- known preparation of vardenafil hydrochloride trihydrate;
- humidity-induced hydrate conversion;
- coated-tablet manufacturing;
- routine solid-state conditioning;
- obviousness of selecting humidity, temperature, and exposure time.
The patent's strongest validity position would likely depend on evidence that the claimed sequence and humidity treatment solved a specific stability, dissolution, or manufacturing problem not predictably addressed by earlier references.
Settlement
A settlement could permit a generic company to launch before the nominal 2027 patent expiration. The commercial date may be confidential or subject to conditions. A public generic launch therefore does not resolve the patent's theoretical scope.
What design-arounds exist for a vardenafil generic?
Potential design-around strategies include:
| Strategy |
Potential effect |
| Use a different vardenafil salt or free base |
May avoid the vardenafil hydrochloride limitation |
| Avoid humid-gas treatment |
May avoid the core process limitation |
| Produce less than 90 mol% trihydrate |
May avoid the conversion threshold |
| Use an uncoated tablet |
May avoid the coated-tablet limitation |
| Apply a non-covered dosage form |
May avoid the tablet limitation |
| Use a process outside the claimed sequence |
May avoid either claim 1 or claim 12, but not necessarily both |
| Use alternative excipients |
May avoid claims 9-11 and 17-19, but not necessarily claims 1 or 12 |
| Use dry processing or solvent-mediated conversion |
May avoid humidified-gas limitations |
The most effective design-around is one that avoids the independent claims. Changing hypromellose, macrogol, or crospovidone alone is not sufficient if the process still performs the claimed humidity conversion on a coated or subsequently coated vardenafil hydrochloride tablet.
How does this patent compare with core vardenafil patents?
| Patent category |
Subject matter |
Commercial relevance |
| Core compound patent |
Vardenafil or related chemical structure |
Broadest historical protection |
| Salt or solid-state patent |
Vardenafil hydrochloride, hydrates, polymorphs |
Protects selected active forms |
| Formulation patent |
Tablet composition, dissolution, stability |
Protects product design |
| U.S. 8,273,876 |
Humidity-mediated conversion during coated-tablet manufacture |
Protects a specific manufacturing route |
| Method-of-use patent |
Erectile or sexual dysfunction treatment |
May affect labeling and use-code risk |
U.S. 8,273,876 is a secondary process patent. It does not replace the core compound patent and does not independently establish exclusivity over all vardenafil tablets.
Is there biosimilar risk for vardenafil?
No. Vardenafil is a small-molecule drug regulated through the ANDA pathway, not a biologic regulated through the biosimilar pathway under section 351(k) of the Public Health Service Act.
The relevant competitive risks are:
- ANDA approval;
- Paragraph IV litigation;
- authorized generic supply;
- settlement-based entry;
- alternative formulation competition;
- international generic manufacturing.
What is the commercial exposure from this patent?
The patent's commercial exposure is narrower than Levitra's total sales exposure because it protects a manufacturing method rather than the active ingredient itself.
Risk is highest for a generic that:
- uses vardenafil hydrochloride trihydrate;
- manufactures coated tablets;
- conditions tablets under humid air;
- targets a conversion level of at least 90 mol%;
- uses common excipients such as microcrystalline cellulose, crospovidone, hypromellose, or macrogol.
Risk is lower where the generic uses a different solid form, a different dosage form, a dry conversion process, or a formulation that does not require the claimed tablet-conditioning step.
Key Takeaways
- U.S. Patent 8,273,876 covers a process for producing coated vardenafil hydrochloride trihydrate tablets.
- Claims 1 and 12 protect opposite process sequences: humidification before coating and coating before humidification.
- The principal technical threshold is conversion of at least 90 mol% of vardenafil hydrochloride into the trihydrate form.
- The broad independent claims do not require air, a specified humidity, or a specified temperature.
- Dependent claims narrow the process to air, 35% to 100% relative humidity, 16°C to 30°C, specified disintegrants, and specified coating agents.
- The patent is a secondary process patent, not a broad vardenafil compound patent.
- Generic competition is governed by ANDA and Paragraph IV principles, not biosimilar law.
- Nominal patent protection extends into 2027, subject to official USPTO term calculations.
- A generic launch does not prove that the patent was invalidated or that all generic manufacturing processes avoid it.
- The principal diligence issue is the proposed generic's actual manufacturing process, not only its finished-product composition.
FAQs
Can a vardenafil generic infringe U.S. Patent 8,273,876 if its final tablet contains trihydrate?
Yes, but final-product identity alone is insufficient. Infringement would depend on whether the tablet was made using the claimed humidified-gas conversion process and satisfies the other claim limitations.
Does replacing hypromellose avoid the patent?
Not necessarily. Replacing hypromellose may avoid certain dependent claims, but claims 1 and 12 do not require hypromellose or macrogol.
Does using nitrogen instead of air avoid all claims?
No. It may avoid claims requiring air, but the independent claims refer more broadly to a moistened gas. Nitrogen could remain relevant to claims 1 and 12 depending on the process conditions.
Can an uncoated vardenafil tablet fall within this patent?
The issued claims require a coated tablet or a method producing a coated tablet. An entirely uncoated product generally would not satisfy that limitation, although the complete manufacturing process and claim interpretation remain material.
Does this patent block international vardenafil sales?
No. A U.S. patent has territorial effect in the United States. Foreign blocking rights require corresponding national or regional family patents, and each jurisdiction requires separate validity, expiration, and infringement analysis.
References
- United States Patent and Trademark Office. (2012). U.S. Patent No. 8,273,876, methods for producing coated tablets comprising vardenafil hydrochloride trihydrate.
- U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
- U.S. Food and Drug Administration. (n.d.). Levitra (vardenafil hydrochloride) prescribing information.
- United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term calculation resources.
- U.S. Food and Drug Administration. (n.d.). Hatch-Waxman amendments and abbreviated new drug applications.
