US Patent 7,662,858: Scope, Claim Construction, Expiration, and Diclofenac Patent Landscape

US Patent 7,662,858 protects a narrow method of using low-dose diclofenac potassium in a dispersible liquid formulation for acute post-bunionectomy pain. The core combination is: 13-25 mg per dose, dosing every approximately 4-8 hours, treatment for at least 24 hours, and no more than approximately 100 mg per day. The patent does not broadly cover diclofenac, diclofenac potassium, or every liquid formulation. Its commercial relevance depends on whether a competing product uses the claimed dosage regimen and the same type of dispersible liquid formulation.

The patent is a method-of-use patent. It does not, based on the quoted claims, claim the composition itself, the capsule shell, the manufacturing process, or every indication for diclofenac potassium.

What does US Patent 7,662,858 cover?

The independent claim requires all of the following elements:

Required element	Scope
Patient	A patient in need of treatment
Condition	Acute post-bunionectomy pain
Route	Oral administration
Active ingredient	Diclofenac potassium
Formulation	Dispersible liquid formulation
Dose	About 13 mg to about 25 mg per administration
Interval	About every 4 to about 8 hours
Duration	At least 24 hours
Daily exposure	No more than about 100 mg per day

A competing product or prescribing regimen must satisfy the full combination to create a strong literal-infringement case under claim 1. A product using diclofenac sodium, a conventional immediate-release tablet, a topical formulation, or a dose outside the claimed range would not literally satisfy every limitation of claim 1.

The claim is narrower than a conventional patent claim covering "a method of treating pain with diclofenac." The limitation to post-bunionectomy pain, dispersible liquid delivery, dose frequency, and daily dose materially constrains its scope.

How strong is the independent claim in US Patent 7,662,858?

Claim 1 has commercial relevance because it combines a defined clinical indication with a specific pharmacokinetic delivery profile and dosing ceiling. Its principal strengths and weaknesses are as follows:

Issue	Assessment
Technical specificity	High
Breadth of indication	Narrow
Breadth of active ingredient	Narrowly limited to diclofenac potassium
Formulation limitation	Significant limitation
Dose limitation	Defined but potentially flexible because of "about"
Frequency limitation	Moderate breadth
Daily-dose limitation	Strong upper boundary
Easy design-around potential	Moderate to high
Dependence on prescribing behavior	High
Vulnerability to prior art	Potentially significant

The word "about" creates numerical flexibility, but it does not eliminate the need for a dose within a commercially reasonable range around 13-25 mg or a total daily amount around 100 mg or less. Courts generally interpret "about" in light of the specification, prosecution history, measurement variability, and technical context.

The phrase "dispersible liquid formulation" is central. A product may not fall within the claim merely because diclofenac potassium dissolves or disperses after a solid dosage form is swallowed. The formulation must be characterized in a manner consistent with the patent's disclosure and claim construction.

What do dependent claims 2 through 20 add?

The dependent claims create narrower positions that may be easier to prove when the accused product and clinical protocol match the claimed details.

Surgical-procedure limitations

Claim 2 covers treatment following bunionectomy where internal fixation is performed. This limitation narrows the patient population but may align with the clinical trial protocol used to support approval.

Dosing-interval limitations

Claims 3 and 4 narrow the dosing interval to:

Approximately every 5-8 hours; or
Approximately every 6 hours.

A regimen of 25 mg every six hours is the most commercially important embodiment because it produces four doses, or 100 mg, over 24 hours.

Treatment-duration limitations

Claims 5 and 6 cover treatment periods of approximately:

30 hours;
48 hours;
72 hours;
96 hours;
120 hours;
144 hours;
168 hours; or
Seven days.

These claims do not necessarily require continuous administration for the entire period unless the claim language and specification impose that interpretation. They are directed to the duration over which the regimen is administered.

Dose-specific limitations

Claim 7 lists doses from approximately 13 mg through 25 mg, including 13.5 mg, 14 mg, 14.5 mg, 15 mg, 15.5 mg, 16 mg, 16.5 mg, 17 mg, 17.5 mg, 18 mg, 18.5 mg, 19 mg, 19.5 mg, 20 mg, 22.5 mg, and 25 mg.

Claim 12 separately identifies approximately 25 mg. This is the practical commercial endpoint because Zipsor, the relevant diclofenac potassium product, is marketed as a 25 mg liquid-filled capsule.

Pharmacodynamic and pharmacokinetic limitations

Claims 8-11 recite clinical and pharmacokinetic results:

Analgesic effect for approximately 6-8 hours;
Plasma diclofenac concentration of approximately 670-1,500 ng/ml in less than 30 minutes;
T(max) of approximately 0.47 hours;
Substantial plasma elimination during the first two hours.

These claims may create litigation issues concerning whether the limitation is an inherent result of practicing the method or an express requirement that must be demonstrated in the accused patient population.

A product could use the same dose and formulation yet avoid literal infringement of a pharmacokinetic claim if it does not produce the claimed concentration or T(max). That does not necessarily avoid claim 1.

Clinical-outcome limitations

Claims 13-16 recite outcomes associated with 25 mg dosing:

Average 48-hour NPRS pain score of approximately 2.49;
Median time to at least 30% pain reduction of approximately 60 minutes;
Median time to meaningful pain relief of approximately 70 minutes;
Clinically significant analgesic efficacy for approximately six hours.

These limitations may be difficult to enforce as pure product or prescribing restrictions because the outcomes can vary by patient, surgical technique, rescue medication, baseline pain, and trial design. They may be more useful as fallback claims than as primary commercial claims.

Capsule and opioid limitations

Claim 18 requires the dispersible liquid formulation to be contained in a capsule. Claim 20 requires that no opioid be co-administered.

Claim 20 is particularly dependent on the actual treatment protocol. If the method allows opioids as rescue medication, the claim's scope may turn on whether "no opioid is co-administered" applies to the full treatment period, the initial dosing period, or the administration event involving diclofenac.

What products are most likely to fall within the claims?

The highest-risk regimen is:

Product or regimen characteristic	Claim exposure
Diclofenac potassium	Required
25 mg dose	Directly matches claims 7 and 12
Liquid-filled or dispersible capsule	Matches claim 18 if legally characterized as dispersible liquid
Every six hours	Directly matches claim 4
Four doses per day	Matches claim 17
100 mg daily	Matches claim 1 and claim 17
Acute post-bunionectomy pain	Matches claim 1
No opioid co-administration	Potentially matches claim 20

A 25 mg diclofenac potassium capsule administered four times daily for acute post-bunionectomy pain presents the clearest literal-infringement scenario.

A conventional 50 mg diclofenac tablet administered twice daily may avoid the quoted claims because the per-dose amount exceeds the claimed range and the formulation is not a dispersible liquid formulation. A 12.5 mg product may avoid the lower dose boundary, subject to the construction of "about 13 mg." Diclofenac sodium would avoid the active-ingredient limitation.

What formulation is protected by US Patent 7,662,858?

The claims protect the use of a dispersible liquid formulation, not every diclofenac potassium dosage form.

The formulation limitation likely distinguishes the claimed method from:

Conventional compressed tablets;
Enteric-coated tablets;
Sustained-release tablets;
Topical gels;
Injectable diclofenac;
Suppositories;
Diclofenac sodium products;
Oral solutions that do not have the claimed dosage-form characteristics.

Claim 18 narrows the formulation further by requiring a capsule. A liquid-filled capsule can satisfy this limitation if the liquid contents are the claimed dispersible liquid formulation. The legal analysis depends on the specification's definition of "dispersible," including whether the formulation is a suspension, emulsion, solution, or another liquid system.

The patent's formulation coverage is therefore use-specific. The quoted claims do not independently prevent a third party from making or selling a different diclofenac potassium liquid formulation for an unrelated indication.

What is the relationship between the patent and Zipsor?

Zipsor is an FDA-approved oral diclofenac potassium product supplied as a liquid-filled capsule. The FDA-approved labeling identifies Zipsor as a 25 mg product for relief of mild to moderate acute pain in adults. The recommended dosage is 25 mg four times daily, which corresponds to a maximum daily dose of 100 mg.[1]

That dosing pattern maps closely to claims 1, 4, 12, 17, and 18:

Zipsor characteristic	Corresponding claim limitation
Diclofenac potassium	Claim 1
25 mg	Claims 7 and 12
Four times daily	Claim 17
100 mg maximum daily dose	Claim 1
Liquid-filled capsule	Claim 18
Acute pain indication	Claim 1, subject to the post-bunionectomy limitation

The principal distinction is that FDA labeling for an approved product may use a broader indication than the patent claim. A product can be labeled for acute pain generally while the patent claim is limited to acute post-bunionectomy pain.

When does US Patent 7,662,858 lose exclusivity?

The patent's earliest ordinary term calculation is based on the earliest effective nonprovisional priority date, reported for this patent family as March 8, 2004. On that basis, the nominal 20-year term would run to March 8, 2024, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and maintenance-fee status under US law.[2]

The relevant legal calculation is:

Term issue	Effect
Earliest effective filing date	Controls the 20-year term
Patent-term adjustment	Can extend the term for USPTO delay
Patent-term extension	May apply for qualifying regulatory delay
Terminal disclaimer	Can shorten the term
Maintenance fees	Nonpayment can cause expiration before the scheduled date
Reissue or correction	Can affect enforceable claim text

A commercial exclusivity analysis must use the USPTO Patent Center record and the FDA Orange Book entry for the listed product. The grant date alone does not determine expiration.

Because the patent is a method-of-use patent, expiration ends the patent-based restriction on the claimed method. It does not necessarily eliminate separate formulation, composition, process, or later-issued patent rights covering the same product.

Is US Patent 7,662,858 listed in the Orange Book?

Orange Book status must be evaluated at the product level, not solely by patent number. The FDA Orange Book identifies patents submitted by an NDA holder for an approved drug product and assigns use codes where applicable.[3]

For a diclofenac potassium liquid-filled capsule, the relevant questions are:

Whether the NDA holder submitted US 7,662,858 to FDA.
Whether FDA published the patent against the relevant NDA.
Whether the listing has a use code limited to post-bunionectomy pain or another acute-pain indication.
Whether the listed expiration date has passed.
Whether later patents remain listed against the product.

A use-code-limited listing would not necessarily block an ANDA applicant seeking approval for all non-patented uses. Under the Hatch-Waxman framework, the applicant could use a section viii statement for a carved-out indication if the proposed labeling omits the patented use.[4]

A method-of-use listing also does not automatically prevent approval of a product with the same active ingredient and dosage form. The applicant's certification and labeling strategy determine the regulatory pathway.

What Paragraph IV challenges are possible?

An ANDA applicant seeking to market a generic diclofenac potassium dispersible liquid capsule could use one or more of four patent certifications:

Certification	Commercial effect
Paragraph I	No patent information listed
Paragraph II	Patent has expired
Paragraph III	Applicant will market after patent expiration
Paragraph IV	Patent is invalid, unenforceable, or will not be infringed
Section viii statement	Proposed labeling omits the patented method

For US 7,662,858, the most relevant historical pathways would be Paragraph IV and section viii.

Paragraph IV theory

A Paragraph IV challenge could argue that:

The claims are anticipated by prior diclofenac liquid formulations or clinical protocols;
The claimed dosage regimen would have been obvious;
"Dispersible liquid formulation" lacks adequate written-description support;
The pharmacokinetic limitations are indefinite;
The post-bunionectomy method is not adequately enabled across the full scope;
The claims are unenforceable because of inequitable conduct or other litigation defenses;
The proposed product does not meet one or more formulation or dosing limitations.

Section viii theory

A section viii strategy could omit post-bunionectomy treatment from the proposed label. This approach is more viable if the generic label does not encourage the patented use and the patent is limited to a specific surgical indication.

The risk increases if the proposed label retains broad acute-pain language that physicians would reasonably use for post-bunionectomy pain. Induced-infringement analysis can turn on labeling language, promotional activity, dosing instructions, and the ordinary use of the product.

What generic launch scenarios exist?

Scenario 1: Same 25 mg liquid-filled capsule and same indication

This is the highest-risk scenario while an enforceable patent remains. A generic applicant would likely need a Paragraph IV challenge, a settlement, a license, or a launch after patent expiration.

Scenario 2: Same capsule, section viii carve-out

The applicant removes post-bunionectomy language and other patented use instructions. Regulatory approval may remain possible, but litigation risk persists if the label or conduct encourages the patented method.

Scenario 3: Different dose

A product supplied at 12.5 mg, 30 mg, or another dose may avoid literal infringement, although the doctrine of equivalents and the interpretation of "about" remain relevant. A different dose also requires its own bioequivalence and clinical justification.

Scenario 4: Different salt

Diclofenac sodium would not literally satisfy a claim limited to diclofenac potassium. It may require a different regulatory and pharmacokinetic strategy.

Scenario 5: Different formulation

A conventional tablet, powder, tablet that disperses only after administration, or non-capsule liquid product may avoid claim 18 and potentially claim 1. The result depends on whether the formulation falls within the patent's construction of "dispersible liquid formulation."

How does this patent compare with a composition or formulation patent?

A method-of-use patent and a formulation patent create different business risks.

Patent type	Main protected subject matter	Typical generic response
Method-of-use	Administration to a defined patient population	Label carve-out or Paragraph IV
Composition	Ingredients, concentrations, excipients	Formulation redesign or Paragraph IV
Dosage form	Capsule, tablet, liquid, release profile	Alternative dosage form
Manufacturing process	Preparation or encapsulation steps	Process redesign
Pharmacokinetic method	Exposure, Tmax, concentration profile	Product and clinical testing challenge

US 7,662,858 is most relevant to a product that combines the claimed formulation with the claimed clinical regimen. It is less effective against a product that changes the salt, dosage form, indication, or dosing schedule.

What manufacturing and intellectual-property barriers remain?

The formulation may present technical barriers even where patent coverage is narrow. A liquid-filled diclofenac potassium capsule requires control of:

Active-ingredient solubility or dispersion;
Chemical stability;
Fill weight and dose uniformity;
Capsule compatibility;
Leakage and shell integrity;
Dissolution and absorption;
Impurity formation;
Packaging and shelf life;
Scale-up reproducibility.

These manufacturing issues do not independently expand the patent's claims. They can, however, make a design-around more expensive and can support trade-secret protection for process parameters, excipient selection, and quality-control methods.

A competitor should separate patent barriers from non-patent barriers. FDA approval, bioequivalence, formulation development, controlled manufacturing, and commercial distribution may remain difficult after the patent expires.

What litigation and settlement issues affect the patent?

The most material litigation questions are claim construction and infringement by the proposed label.

Courts would likely focus on:

The meaning of "dispersible liquid formulation."
Whether the phrase "about 13 to about 25 mg" includes doses outside the stated range.
Whether post-bunionectomy pain is a required patient condition.
Whether all administrations must occur within the claimed interval.
Whether the 100 mg daily cap is measured over a calendar day or any 24-hour period.
Whether the pharmacokinetic results are claim limitations or inherent consequences.
Whether rescue opioids defeat claim 20.
Whether a carved-out label sufficiently avoids induced infringement.

A settlement could allow an ANDA applicant to launch on a licensed date before full patent expiration. Settlement terms may include delayed entry, royalty-bearing supply, a covenant not to sue, or restrictions on indication and promotion. A settlement cannot be inferred from the patent grant or FDA approval alone. It must be established from court filings, FDA records, or a disclosed agreement.

Which companies are relevant to the competitive landscape?

The relevant competitive set includes:

The NDA holder and marketer of the branded diclofenac potassium liquid-filled capsule;
Generic manufacturers developing diclofenac potassium oral products;
Manufacturers of diclofenac sodium tablets and capsules;
Nonsteroidal anti-inflammatory drug competitors;
Opioid and non-opioid acute-pain therapies;
Developers of alternative oral liquid or fast-acting formulations.

The patent is unlikely to block the broader NSAID market. Its commercial effect is concentrated in the segment combining diclofenac potassium, oral liquid delivery, 25 mg dosing, and acute postoperative pain treatment.

What revenue exposure does the patent create?

Revenue exposure depends on the share of product sales attributable to the patented regimen rather than to unpatented acute-pain uses.

The highest exposure exists where:

The product is sold primarily as a 25 mg liquid-filled capsule;
The approved label includes or encourages post-bunionectomy treatment;
Physicians routinely prescribe four-times-daily dosing;
No alternative formulation has meaningful market share;
The patent is listed and enforceable during the expected generic launch window.

Exposure is lower where:

The patent term has ended;
The Orange Book listing is expired or delisted;
Generic applicants can use a section viii carve-out;
Competitors use diclofenac sodium or conventional tablets;
Prescribing shifts to other NSAIDs or non-opioid analgesics.

Key Takeaways

US 7,662,858 is a narrow method-of-use patent, not a broad diclofenac composition patent.
Claim 1 requires post-bunionectomy pain, oral diclofenac potassium, a dispersible liquid formulation, 13-25 mg per dose, dosing every 4-8 hours, at least 24 hours of treatment, and no more than 100 mg per day.
The clearest commercial match is 25 mg administered every six hours, four times daily.
Claims 4, 12, 17, and 18 provide the strongest product-regimen alignment for a 25 mg liquid-filled capsule.
Claims 9-16 rely on pharmacokinetic and clinical outcomes that may be harder to enforce than the core dosage and formulation limitations.
A conventional tablet, diclofenac sodium product, different dose, or indication carve-out may provide a design-around.
The relevant regulatory pathways are Paragraph IV, Paragraph III after expiration, and section viii labeling carve-out.
Current exclusivity requires confirmation against the USPTO term record, FDA Orange Book, and any later patents covering the product.
Biosimilar risk is not applicable because diclofenac potassium is a small-molecule drug, not a biologic.
The patent's principal business value is concentrated in a specific acute-pain product and regimen, not the entire NSAID market.

FAQs About US Patent 7,662,858

Does US 7,662,858 cover all diclofenac potassium products?

No. The quoted claims require a specific oral dispersible liquid formulation, dose range, dosing interval, acute post-bunionectomy use, and daily dose limit.

Can a generic use a different diclofenac salt?

A diclofenac sodium product would not literally satisfy claims limited to diclofenac potassium. It could remain subject to separate patents, regulatory requirements, and equivalence considerations.

Does a 25 mg dose automatically infringe the patent?

No. Dose alone is insufficient. The formulation, indication, dosing interval, treatment duration, and daily amount must also fall within the claim.

Can an ANDA applicant omit the post-bunionectomy indication?

Potentially, through a section viii labeling strategy. The applicant must avoid labeling, promotion, or other conduct that encourages the patented use.

Are biosimilars relevant to this patent?

No. Diclofenac potassium is a small-molecule active ingredient. The relevant competitors are generic drug applicants, not biosimilar sponsors.

References

U.S. Food and Drug Administration. (2009). Zipsor (diclofenac potassium) liquid filled capsule prescribing information.
United States Code, 35 U.S.C. §§ 154, 156.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2015). Code of Federal Regulations, 21 C.F.R. § 314.94: Content and format of an ANDA.
United States Patent and Trademark Office. (2010). U.S. Patent No. 7,662,858, Methods and compositions for treating acute pain.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Cosette	ZIPSOR	diclofenac potassium	CAPSULE;ORAL	022202-001	Jun 16, 2009	AB	RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial				NONSTEROIDAL ANTI-INFLAMMATORY DRUG INDICATED FOR RELIEF OF MILD TO MODERATE ACUTE PAIN	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Summary for Patent: 7,662,858