United States Drug Patent 7,320,800: Claims, Scope, Expiration, and Progesterone Patent Landscape

U.S. Patent No. 7,320,800 covers methods of administering a vaginal tablet containing natural or micronized progesterone, an effervescent, and excipients. The broadest surviving claim concept is a vaginal progesterone tablet that produces a progesterone Tmax between 3.05 and 9.75 hours. Claim 1 adds a specific manufacturing sequence, while claim 4 omits that sequence and is therefore the principal composition-and-performance method claim.

The patent was issued on January 22, 2008. Its statutory term has ended under the ordinary 20-year term calculation from the nonprovisional filing date, subject to any patent-term adjustment. The patent therefore does not present a current U.S. blocking right in 2025. Its historical importance relates to Ferring's Endometrin progesterone vaginal insert and to generic challenges directed at the product's formulation and pharmacokinetic profile.

What does U.S. Patent 7,320,800 protect?

U.S. Patent 7,320,800 protects a method, not a standalone progesterone composition. The claimed method requires vaginal placement of a tablet that contains:

Natural progesterone, or micronized natural progesterone;
Pharmaceutically acceptable excipients;
An effervescent; and
A formulation that produces a Tmax between 3.05 and 9.75 hours after vaginal administration.

The patent is associated with the vaginal progesterone product Endometrin, a 100 mg progesterone vaginal insert approved by the FDA for luteal support in assisted reproductive technology procedures. FDA-approved Endometrin labeling identifies progesterone as the active ingredient and describes vaginal administration of a 100 mg insert twice daily.[2]

The independent claims differ materially:

Claim	Core subject matter	Distinguishing limitations
1	Vaginal delivery method	Tablet consists of natural progesterone, excipients, and effervescent; specified wetting, drying, mixing, and direct-compaction process; Tmax of 3.05-9.75 hours
4	Vaginal delivery method	Tablet consists of micronized natural progesterone, excipients, and effervescent; Tmax of 3.05-9.75 hours
2	Depends from claim 1	At least about 50 mg progesterone
3	Depends from claim 1	Twice-daily dosing
5	Depends from claim 4	At least 50 mg progesterone
6	Depends from claim 4	Twice-daily dosing

Claim 4 is the commercially important independent claim because it does not require the manufacturing steps recited in claim 1. A product could fall within claim 4 even if it was manufactured by a process other than the wetting, drying, and direct-compaction sequence in claim 1.

How should claim 1 of patent 7,320,800 be construed?

Claim 1 combines product, process, administration, dosing-performance, and pharmacokinetic limitations. Each limitation must be satisfied for literal infringement.

Vaginal placement and dissolution

The method requires placing the tablet in the vagina and retaining it there until dissolution. An orally administered progesterone capsule, injectable progesterone, transdermal product, vaginal gel, vaginal ring, or non-dissolving implant would not satisfy this limitation.

A vaginal tablet that is removed before dissolution also presents a claim-compliance issue because the claim expressly requires retaining the tablet until it dissolves.

Closed “consisting of” language

Claims 1 and 4 state that the tablet consists of progesterone, excipients, and an effervescent. “Consisting of” is generally closed transitional language. It can exclude additional unrecited ingredients that materially alter the claimed composition, although interpretation depends on the claim, specification, and prosecution history.

The closed language creates a design-around pathway. A competing product containing an additional functional ingredient may argue that it falls outside the claimed composition. That strategy would require analysis of whether the additional ingredient is merely an incidental impurity or an excluded component.

Natural progesterone

Claim 1 requires natural progesterone. Claim 4 requires micronized natural progesterone as the active ingredient. The claims do not cover synthetic progestins merely because they have progesterone-like activity.

Examples of products that would not ordinarily satisfy this active-ingredient limitation include:

Medroxyprogesterone acetate;
Megestrol acetate;
Norethindrone;
Levonorgestrel; and
Other synthetic progestogens.

Micronization is expressly required by claim 4. Claim 1 does not use the word “micronized,” although the specification and prosecution history could affect the interpretation of natural progesterone and the claimed dosage form.

Effervescent

The effervescent is a central formulation limitation. It likely provides gas generation, disintegration, wetting, or dispersion within the vaginal environment. A vaginal tablet containing progesterone and conventional excipients but no effervescent would have a substantial noninfringement position against claims 1 and 4.

Typical effervescent systems use an acid component and a carbonate or bicarbonate component. The claims, as provided, do not require a particular acid, base, gas volume, pH, or disintegration time.

Tmax range

The required Tmax is between 3.05 and 9.75 hours after vaginal placement. This limitation narrows the claims from all vaginal progesterone tablets to tablets exhibiting a specified pharmacokinetic result.

The range creates several enforcement issues:

Tmax depends on the study population, sampling schedule, assay, dose, and statistical treatment.
A study with sampling only at two-hour intervals may not establish the precise peak time.
Interpatient variability may produce Tmax values outside the range for individual patients.
The relevant question may be whether the accused product is designed to produce the claimed Tmax, whether it typically produces that result, or whether the result is required in every administration.
An abbreviated new drug application may provide formulation and pharmacokinetic data that make the limitation easier to assess than commercial use alone.

The range is strategically significant because it may capture the release and absorption behavior of Endometrin while excluding faster- or slower-dissolving vaginal progesterone formulations.

What are the manufacturing limitations in claim 1?

Claim 1 requires a defined manufacturing sequence:

Water is mixed with natural progesterone in the absence of excipients.
The wetted progesterone is dried to form dry progesterone.
The dry progesterone is mixed with excipients and an effervescent.
The mixture is formed into a dry tablet by direct compaction.

The first step is unusually specific. The progesterone must be wetted before excipients are added. The claim excludes a process in which progesterone is first combined with excipients and then wetted, unless the process still satisfies the claim under the applicable construction.

The final compaction step is also limited. Wet granulation after addition of excipients, roller compaction, extrusion, compression molding, or tableting after a separate granulation process could avoid literal infringement of claim 1 if the process does not qualify as direct compaction.

These process limitations do not appear in claim 4. A competing product can therefore avoid claim 1 through a different manufacturing route while still requiring analysis under claim 4.

How do claims 2, 3, 5, and 6 change infringement risk?

The dependent claims impose commercial-use limitations:

Claims 2 and 5 require at least about 50 mg of progesterone.
Claims 3 and 6 require twice-daily administration.

The 50 mg limitation does not require exactly 50 mg. A 100 mg insert would fall within the numerical limitation if the other claim elements were present. A product containing less than 50 mg could avoid these dependent claims but would remain exposed to claims 1 and 4.

The twice-daily limitation is important because Endometrin labeling directs administration of one 100 mg insert in the morning and one in the evening for luteal support.[2] A generic label that mirrors that regimen could create a direct or induced infringement theory while the patent was enforceable.

A once-daily product would not satisfy claims 3 or 6, although it could still implicate claims 1, 2, or 4 if the other limitations were met.

When did U.S. Patent 7,320,800 expire?

U.S. Patent 7,320,800 issued January 22, 2008.[1] Patent records identify a 2002-era nonprovisional filing for the patent. Under the Hatch-Waxman patent-term framework, the ordinary term is 20 years from the earliest effective nonprovisional filing date, not 20 years from the issue date.

On the ordinary calculation, the patent term ended around November 2022, subject to patent-term adjustment. The patent is therefore expired by 2025. The exact term date must be taken from the USPTO Patent Center term calculation because patent-term adjustment, terminal disclaimers, or other prosecution events can change the date.

Event	Date or period
Nonprovisional filing period	2002-era filing
Patent issued	January 22, 2008
Ordinary 20-year term estimate	Approximately November 2022
Enforceability in 2025	No current enforceable term under the ordinary expiration record

Expiration removes the patent's ability to support a new U.S. infringement action based on post-expiration conduct. It does not eliminate historical litigation, damages issues, prosecution-history relevance, or the commercial value of technical disclosures.

What is the Orange Book status of patent 7,320,800?

The patent was listed in the FDA Orange Book for Endometrin, a progesterone vaginal insert marketed by Ferring Pharmaceuticals.[3] Orange Book listing does not itself establish validity or infringement. It identifies patents submitted by the NDA holder as potentially covering the approved drug, its formulation, or an approved method of use.

The patent's listing was relevant to ANDA applicants because a generic applicant had to address the listed patent through one of four certifications:

Paragraph I: no patent information was submitted;
Paragraph II: the patent had expired;
Paragraph III: the applicant would wait until expiration;
Paragraph IV: the patent was invalid, unenforceable, or would not be infringed.

After expiration, a Paragraph II certification becomes the relevant pathway for an applicant addressing this patent, assuming no later patent independently blocks approval or launch. Orange Book listing should therefore be reviewed by product and patent edition rather than treated as a permanent barrier.

Which companies challenged the Endometrin patent estate?

The principal historical challenge involved Watson Laboratories, Inc., which filed an ANDA for a generic version of Endometrin and triggered litigation by Ferring. The dispute included Ferring patents covering Endometrin, including U.S. Patent Nos. 6,881,721 and 7,320,800. The Federal Circuit addressed related Ferring patent litigation in Ferring B.V. v. Watson Laboratories, Inc.[4]

The litigation illustrates the primary generic risk structure:

Risk category	Relevance to patent 7,320,800
Paragraph IV challenge	Asserted invalidity or noninfringement before expiration
Formulation design-around	Remove or change the effervescent system
Process design-around	Avoid wetting progesterone before excipient addition or avoid direct compaction
PK design-around	Produce a Tmax outside 3.05-9.75 hours
Label carve-out	Avoid twice-daily or otherwise patented method language where FDA rules permit
Post-expiration entry	Patent no longer blocks entry after expiration

Public litigation involving related Endometrin patents does not establish that every claim of patent 7,320,800 was valid, infringed, or enforceable. Those questions depend on the specific judgment, claim construction, prosecution history, and settlement terms.

What formulation patents competed with patent 7,320,800?

The relevant competitive patent landscape included several delivery formats:

Endometrin vaginal insert

Endometrin is a dry vaginal insert containing micronized progesterone. Its commercial profile aligns closely with claims 4-6 because the product uses a vaginal dosage form, a 100 mg progesterone dose, and a twice-daily regimen.[2]

Crinone vaginal gel

Crinone is a progesterone vaginal gel rather than an effervescent tablet. Its different dosage form and excipient system reduce direct exposure to tablet-specific claims. Gel patents and regulatory exclusivity issues were separate from the Endometrin tablet estate.

Prometrium capsules

Prometrium contains micronized progesterone in an oral capsule. Oral administration does not satisfy the vaginal-placement limitations of patent 7,320,800.

Compounded vaginal progesterone

Compounded suppositories, capsules, and tablets can raise formulation and method issues, but they do not automatically infringe. The effervescent, micronization, Tmax, dose, administration route, and dosing schedule must be assessed against each claim.

How strong was the patent estate for Endometrin?

The patent estate was strongest before expiration where a generic product copied the commercial product closely. Claim 4 created the principal risk because it omitted the detailed manufacturing process in claim 1. A generic matching the Endometrin dosage form, active ingredient, effervescent system, dose, vaginal route, and pharmacokinetic profile could face a more direct challenge than a product using a materially different formulation.

The estate had several weaknesses:

The claims were method claims rather than broad composition claims.
The effervescent limitation allowed formulation redesign.
Claim 1 contained multiple process limitations.
The Tmax range could create proof and claim-construction disputes.
Claims 3 and 6 were limited to twice-daily administration.
The patent term has ended.

The estate's commercial value therefore depended heavily on product similarity and on the timing of generic development.

What generic launch scenarios existed for Endometrin?

Before patent expiration, a generic applicant had four principal launch strategies:

Full-label launch after Paragraph IV litigation. The applicant could prevail on invalidity, noninfringement, or enforceability.
Formulation design-around. The applicant could use a non-effervescent tablet, a different excipient system, or a different release profile.
Method-of-use carve-out. The applicant could omit patented use language where FDA labeling rules permitted.
Launch after patent expiration. The applicant could rely on a Paragraph II certification.

After the patent's expiration, 7,320,800 no longer creates a standalone launch barrier. Remaining risks would come from other unexpired patents, regulatory exclusivity, manufacturing constraints, FDA approval status, or contractual restrictions.

What manufacturing and geographic barriers remain?

The patent was a United States right. It did not directly block manufacture, sale, or use outside the United States. Parallel protection would require corresponding patents in individual jurisdictions, with separate expiration and validity analyses.

The technical barriers were narrower than the commercial barriers. A manufacturer would need to reproduce a stable micronized progesterone tablet with adequate content uniformity, dissolution, vaginal tolerability, and manufacturing reproducibility. Those requirements can remain commercially relevant after patent expiration, but they are not equivalent to patent exclusivity.

A product using the same process or formulation after expiration does not infringe an expired U.S. patent. Trade secrets, regulatory know-how, trademarks, and manufacturing contracts may still affect market entry.

What licensing deals and settlement agreements affected the patent?

Patent 7,320,800 was commercially connected to Ferring's Endometrin product and its U.S. regulatory strategy. Publicly reported litigation establishes the existence of ANDA disputes involving Ferring and Watson. Settlement agreements in Hatch-Waxman matters may contain confidential terms, launch dates, authorized-generic provisions, or licensing rights that are not fully disclosed in public pleadings.

No settlement should be treated as proof that the patent was valid or infringed. The relevant business question is whether the agreement authorized entry before patent expiry. Because the patent has expired, any historical settlement restriction tied solely to this patent has limited present blocking value.

Key Takeaways

U.S. Patent 7,320,800 covers vaginal delivery of natural or micronized progesterone in an effervescent tablet.
Claim 4 is the broadest practical claim because it omits the manufacturing sequence required by claim 1.
The critical limitations are vaginal administration, tablet dissolution, effervescent content, micronized natural progesterone, and a Tmax of 3.05-9.75 hours.
Claims 2 and 5 add a dose of at least about 50 mg.
Claims 3 and 6 add twice-daily dosing.
Claim 1 requires wetting progesterone before adding excipients, drying the progesterone, and direct compaction.
The patent issued January 22, 2008, and expired under the ordinary 20-year term framework around 2022, subject to USPTO term adjustment.
The patent was relevant to Ferring's Endometrin product and historical ANDA litigation involving Watson.
The patent no longer presents a current U.S. blocking right, but other Endometrin patents, regulatory requirements, and manufacturing barriers require separate review.

FAQs

Does patent 7,320,800 cover oral micronized progesterone?

No. The asserted claims require placing the tablet in the vagina and retaining it there until dissolution.

Does a non-effervescent progesterone vaginal tablet fall within the claims?

A non-effervescent tablet would generally avoid the express effervescent limitation in claims 1 and 4, subject to the full claim language and any applicable equivalents analysis.

Does a 100 mg vaginal progesterone insert satisfy the dose limitations?

Yes, a 100 mg product satisfies the “at least about 50 mg” limitation in claims 2 and 5 if the remaining limitations are met.

Can a once-daily vaginal progesterone product infringe patent 7,320,800?

It would not satisfy claims 3 or 6, which require twice-daily dosing. It could still require analysis under independent claims 1 and 4.

Is Endometrin still protected by patent 7,320,800?

No. Patent 7,320,800 no longer provides an enforceable U.S. patent term under the ordinary expiration framework. Other patents or regulatory protections must be assessed separately.

References

United States Patent and Trademark Office. (2008). U.S. Patent No. 7,320,800, vaginal tablet for administration of progesterone. https://patents.google.com/patent/US7320800B2/en
U.S. Food and Drug Administration. (2024). Endometrin progesterone vaginal insert: Prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/
U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/
Ferring B.V. v. Watson Laboratories, Inc., 764 F.3d 1401 (Fed. Cir. 2014).

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Israel	127129	Nov 18, 1998

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	1176200	⤷ Start Trial
Canada	2568823	⤷ Start Trial
Denmark	1131052	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,320,800

Summary for Patent: 7,320,800