US Patent 5,514,698: Claim Scope, Expiration, and Antifungal Vaginal Cream Patent Landscape

US Patent 5,514,698 covers a viscous vaginal cream designed to remain substantially thick after exposure to vaginal temperature. Its core protection is a formulation combining an imidazole antifungal, fatty-acid ester, aliphatic alcohol, surfactant, antioxidant, inorganic base, water, and defined viscosity or HLB characteristics. The patent issued on May 7, 1996 and, based on the pre-Uruguay Round patent-term regime, its ordinary 17-year term expired on May 7, 2013.[1] It therefore does not create current U.S. patent exclusivity or a present generic-launch barrier.

What does US Patent 5,514,698 protect?

The patent protects two related subject-matter groups:

A long-lasting viscous antifungal vaginal cream.
A manufacturing process for producing that cream.

The principal formulation claim is claim 1. It requires every listed component and limitation:

Required element	Claimed range or condition
Imidazole antifungal	About 0.4% to 10.0%
Fatty-acid ester	About 1.0% to 5.0%
Aliphatic alcohols	About 1.0% to 25.0%
Surfactant	About 2.0% to 5.0%
Antioxidant	About 0.02% to 0.20%
Inorganic base	Sufficient amount to produce pH about 3.0 to 7.0
Water	Required
Rheology	Viscosity maintained when heated to 37°C

The use of “comprising” makes the claim open-ended. A competing product can contain additional excipients and still fall within claim 1 if it contains all required elements within the claimed ranges.

How broad is claim 1 for antifungal vaginal creams?

Claim 1 is structurally broad but compositionally narrow. It does not require one specific active ingredient, ester, alcohol, surfactant, or antioxidant. It does require the combination of all six formulation categories and the temperature-related viscosity limitation.

Antifungal scope

Claim 2 identifies the covered imidazoles as:

Miconazole
Econazole
Terconazole
Saperconazole
Itraconazole
Ketoconazole
Clotrimazole

Claim 2 is dependent on claim 1. It narrows the active ingredient but does not expand the base claim. A formulation using an imidazole outside the listed group could potentially remain within claim 1 because claim 1 covers “an imidazole antifungal agent” generally, subject to the other limitations.

Saperconazole was listed in claim 2, while claim 13 uses “sperconazole.” The latter appears to be a spelling error. The patent specification and prosecution history would control whether the discrepancy has legal significance.

Excipient scope

Claim 3 identifies four esters:

Isopropyl stearate
Isopropyl myristate
Isopropyl palmitate
Isopropyl laurate

Claim 4 identifies:

Cetyl alcohol
Stearyl alcohol
Propylene glycol

Claim 5 identifies polysorbate 60 and polysorbate 80. Claim 6 narrows the surfactant to an HLB value of about 15. Claim 7 specifies butylated hydroxyanisole, or BHA, as the antioxidant. Claims 8 and 9 specify sodium hydroxide and potassium hydroxide as the inorganic base.

The dependent claims create a series of narrower combinations. For example, a formulation containing miconazole, isopropyl myristate, cetyl alcohol, polysorbate 60, BHA, sodium hydroxide, and water would represent a direct example of the claimed architecture if its concentrations, pH, and viscosity also met the required limitations.

What viscosity limitations are required by the patent?

Claims 10 and 11 add performance-based limitations.

Claim 10 requires a viscosity of at least about 3.1 Pa·s at 37°C after at least eight minutes. The claim text describes the unit as “Eta (Pas),” which appears to refer to dynamic viscosity expressed in Pa·s.

Claim 11 requires that viscosity decrease by no more than about 10% at 37°C after at least eight minutes. This limitation requires a defined comparison between the initial viscosity and the viscosity after exposure to 37°C.

These claims are commercially important because they target the product’s behavior after administration rather than only its ingredient list. They also create potential enforcement issues:

The claim does not state the exact rheometer or test geometry.
It does not specify shear rate, spindle, temperature equilibration, or sample preparation.
“After at least eight minutes” may require interpretation against the specification.
Claim 11 requires a baseline measurement, but the claim language does not expressly define the baseline condition.

The specification and prosecution history would be central to construing these limitations. Without a validated test method, an accused product could challenge infringement through measurement reproducibility and claim-construction arguments.

What does claim 19 add to the patent scope?

Claim 19 independently recites the same principal ingredient categories and concentration ranges as claim 1. It adds the requirement that the surfactant have an HLB “close to” the HLB value of the oil phase.

This limitation is technically directed to emulsion compatibility. Matching or approximating the surfactant HLB to the oil-phase requirement can improve emulsion stability and help preserve viscosity at elevated temperature.

The phrase “close to” is less precise than a numeric HLB range. Its enforceability would depend on how the patent specification defines the relationship and whether a person skilled in formulation science could determine the boundary with reasonable certainty.

What manufacturing process does claim 12 protect?

Claim 12 covers a sequence for preparing the cream:

Mix an oil phase containing aliphatic alcohol, ester, and surfactant.
Separately mix an aqueous phase containing water and a humectant.
Separately mix surfactant, water, and antifungal agent to create a slurry.
Separately mix alkaline buffer compound and water.
Add the aqueous phase to the oil phase, mix, and cool.
Add the antifungal slurry after cooling.
Add the alkaline buffer mixture to adjust pH.

The order of operations is significant. The claim does not merely cover the ingredients. It covers the staged preparation method and the post-cooling addition of the antifungal slurry.

Claims 13 through 17 narrow the process by specifying the active, ester, alcohol, and surfactant. Claim 18 is a product-by-process claim covering a cream “made in accordance with” claim 12.

Product-by-process exposure

Claim 18 may be narrower than the composition claims because it expressly ties the product to the claimed manufacturing sequence. In U.S. patent practice, product-by-process claims generally turn on the identity of the resulting product, but the process language can remain relevant to infringement and validity depending on the claim construction and controlling precedent.[2]

A manufacturer using a materially different process could therefore face a different infringement analysis under claim 18 than under claims 1 or 19. The composition claims remain the principal risk provisions because they do not require the claimed manufacturing sequence.

Which formulation changes could design around the claims?

Potential design-around paths include:

Design-around approach	Likely claim issue
Use a non-imidazole antifungal	Avoids the active-agent limitation
Use an ester outside the claimed fatty-acid ester range or category	May avoid the ester limitation
Omit BHA or use an antioxidant outside the claimed range	Avoids claim 7, but not necessarily claim 1 if another antioxidant satisfies claim 1
Use a surfactant outside the 2% to 5% range	May avoid claim 1
Use a non-polysorbate surfactant	Avoids claims 5 and 16, but not necessarily claim 1
Formulate outside pH 3.0 to 7.0	May avoid the pH limitation
Use a nonaqueous dosage form	Avoids the water limitation
Produce a cream that loses more than 10% viscosity at 37°C	May avoid claim 11
Use a low-viscosity or rapidly liquefying formulation	May avoid claims 10 and 11
Use a process that does not add the antifungal slurry after cooling	May avoid claims 12 and 18

These approaches require analysis under the doctrine of equivalents. A minor numerical change may not avoid infringement if the changed feature performs substantially the same function in substantially the same way to achieve substantially the same result. The expired status of the patent makes that issue historical rather than a current commercial barrier.

When did US Patent 5,514,698 lose exclusivity?

The patent issued on May 7, 1996. Because the application appears to fall under the pre-June 8, 1995 patent-term regime, the ordinary term was 17 years from issuance. On that basis, the patent expired on May 7, 2013.[1]

Event	Date
U.S. patent grant	May 7, 1996
Ordinary patent term	17 years from grant
Expected expiration	May 7, 2013
Current enforceability	Expired
Current U.S. composition exclusivity	None from this patent

A patent-term adjustment, patent-term extension, terminal disclaimer, or other prosecution-specific event could alter the calculation. The patent number and claim text alone do not establish any such modification. No current patent exclusivity should be attributed to US 5,514,698 without a separate USPTO term record.

What is the Orange Book status of US Patent 5,514,698?

The claims concern a pharmaceutical formulation and could historically have been relevant to an approved vaginal antifungal product. That does not establish that the patent was listed in the FDA Orange Book.

Orange Book listing is product-specific. It depends on:

The approved drug application.
The active ingredient and dosage form.
The patent’s relationship to the approved product.
FDA listing submissions and certifications.
Whether the patent was timely submitted and remained listed.

The Orange Book is therefore not a complete patent-family database. A patent may be relevant to a formulation without appearing in the current Orange Book, and an expired patent does not create current FDA approval-blocking exclusivity.[3]

Because US 5,514,698 expired in 2013, it cannot support a current 30-month stay based on a new Paragraph IV certification. Any Paragraph IV dispute involving the patent would have been historical.

Were Paragraph IV challenges or patent litigation likely to affect generic entry?

A Paragraph IV certification is relevant only while an unexpired listed patent remains capable of delaying approval. For this patent, the ordinary term has ended. A current ANDA applicant would not face a viable patent-term barrier from US 5,514,698 alone.

The claim structure could have supported historical litigation over:

Miconazole or clotrimazole vaginal creams.
The concentration of fatty-acid esters.
Polysorbate 60 or 80 levels.
pH adjustment with sodium or potassium hydroxide.
37°C viscosity testing.
The process sequence for adding antifungal slurry after cooling.

The supplied claim text does not establish a particular defendant, complaint, settlement, consent judgment, license, or covenant not to sue. No litigation or settlement conclusion should be attributed to this patent solely from the claims.

How strong is the patent estate for this technology?

The patent estate represented by US 5,514,698 is currently weak as a commercial exclusion right because the patent is expired. Its technical claim design was stronger in three areas:

It combined quantitative formulation ranges with functional viscosity behavior.
It protected both composition and manufacturing sequence.
It used dependent claims to identify commercially plausible excipients and actives.

Its vulnerabilities included:

Broad but potentially crowded formulation categories.
Ambiguous terms such as “long-lasting,” “about,” and “close to.”
Measurement dependence in claims 10 and 11.
Potential prior-art exposure for conventional creams containing imidazoles, fatty alcohols, surfactants, antioxidants, and pH adjusters.
Limited value of the process claims if competitors obtained equivalent products through different processing steps.

The patent is best viewed as an expired formulation patent with historical relevance to vaginal antifungal cream development, not as a live barrier to generic or branded competition.

How does this patent compare with biosimilar and generic risk?

This is a small-molecule formulation patent, not a biologic patent. Biosimilar law is therefore not the relevant regulatory framework. The competitive pathway is an ANDA or, depending on the product and formulation, another abbreviated or application-specific route under the Federal Food, Drug, and Cosmetic Act.

The main current risks are:

Formulation differentiation.
FDA bioequivalence or therapeutic-equivalence requirements.
Device or applicator considerations.
Manufacturing consistency.
Any later, unexpired patents covering a branded product.

US 5,514,698 itself does not create biosimilar risk, data exclusivity, or current generic delay.

What geographic coverage does US Patent 5,514,698 provide?

The patent provides U.S. rights only. It does not establish protection in Canada, Europe, Japan, China, or other markets. Foreign counterparts would require separate patent numbers, filing dates, legal statuses, and expiration analyses.

A U.S. expiration does not determine the status of corresponding foreign family members. Conversely, an unexpired foreign counterpart would not restore U.S. exclusivity.

Key Takeaways

US 5,514,698 covers viscous antifungal vaginal creams with specified ingredient categories, concentration ranges, pH, and 37°C viscosity behavior.
Claims 1 and 19 are the principal composition claims.
Claim 12 covers a staged manufacturing process, including post-cooling addition of an antifungal slurry.
Claims 10 and 11 depend on viscosity testing at 37°C and may raise measurement and construction issues.
Claim 19 uses the less precise limitation that the surfactant HLB is “close to” the oil-phase HLB.
The patent issued May 7, 1996 and ordinarily expired May 7, 2013.
It provides no current U.S. patent exclusivity or present Paragraph IV barrier.
The patent concerns a small-molecule formulation, so biosimilar analysis is not applicable.
Any current commercial risk would arise from later patents, FDA requirements, or product-specific regulatory protections rather than this patent.

FAQs About US Patent 5,514,698

Does US Patent 5,514,698 still block generic miconazole vaginal cream?

No. The patent’s ordinary U.S. term expired in 2013. It cannot independently block a current generic launch.

What is the most important claim in US Patent 5,514,698?

Claim 1 is the central composition claim. It requires the complete excipient and antifungal combination, specified concentration ranges, pH, water, and viscosity retention at 37°C.

Can a cream using polysorbate 80 avoid the patent?

Not necessarily. Polysorbate 80 is expressly covered by claim 5 and claim 16. A product using it must also be assessed against claim 1 and the viscosity limitations.

Does using clotrimazole create infringement risk under the patent?

Clotrimazole is expressly listed in claim 2. During the patent term, a clotrimazole cream could have raised risk if it also met the base composition, concentration, pH, and viscosity limitations. The patent is now expired.

Is claim 12 limited to a specific antifungal manufacturing process?

Yes. Claim 12 requires a defined sequence, including separate oil, aqueous, slurry, and alkaline-buffer mixtures and addition of the antifungal slurry after cooling. Claims 1 and 19 are broader composition claims because they do not recite that sequence.

References

United States Patent and Trademark Office. (1996). U.S. Patent No. 5,514,698.
United States Court of Appeals for the Federal Circuit. (2009). Abbott Laboratories v. Sandoz, Inc., 566 F.3d 1282.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

Details for Patent: 5,514,698

Summary for Patent: 5,514,698