Details for Patent: 8,999,387

Which drugs does patent 8,999,387 protect, and when does it expire?

Patent 8,999,387 protects ZORVOLEX and is included in one NDA.

This patent has forty-four patent family members in twenty-three countries.

Summary for Patent: 8,999,387

Title:	Formulation of diclofenac
Abstract:	The present invention relates to methods for producing particles of diclofenac using dry milling processes as well as compositions comprising diclofenac, medicaments produced using diclofenac in particulate form and/or compositions, and to methods of treatment of an animal, including man, using a therapeutically effective amount of diclofenac administered by way of said medicaments.
Inventor(s):	Aaron Dodd, Felix Meiser, Marck Norret, Adrian Russell, H William Bosch
Assignee:	Iceutica Pty Ltd
Application Number:	US14/167,652
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,999,387
Patent Claim Types: see list of patent claims	Use; Composition; Formulation; Dosage form;

US Patent 8,999,387: Diclofenac Acid Particle-Size, Dissolution, and Patent Landscape Analysis

US Patent 8,999,387 protects methods of treating pain with 18 mg or 35 mg solid oral doses of diclofenac acid formulated with submicron particles and defined dissolution performance. The patent is directed to the product's administered dose and performance characteristics, rather than to a broad diclofenac composition or every use of diclofenac.

The principal commercial relevance is Zorvolex, an immediate-release diclofenac capsule containing 18 mg or 35 mg of diclofenac. The patent's strongest protection combines four limitations: diclofenac acid, a particle-size range, a specified dose, and rapid dissolution under a defined USP test.

What patents protect diclofenac acid products covered by US 8,999,387?

US 8,999,387 is a method-of-treatment patent with product-performance limitations. Its independent claims cover:

Claim group	Dose	Median particle size	Dissolution threshold	Dosage form
Claims 1-10	18 mg diclofenac acid	Greater than 25 nm and less than 1,000 nm	At least 94% released by 75 minutes	Solid oral unit dose
Claims 11-20	35 mg diclofenac acid	Greater than 25 nm and less than 1,000 nm	At least 95% released by 75 minutes	Solid oral unit dose
Claims 21-24	18 mg or 35 mg	Depends on parent claim	Depends on parent claim	At least once daily; single dose provides perceptible pain relief

The patent also narrows the particle-size limitation through dependent claims:

• Less than 900 nm;
• Less than 800 nm;
• Less than 700 nm; and
• For selected claims, a D(90) below specified thresholds ranging from 3,000 nm to 1,700 nm.

The claims cover tablets and capsules, but they do not require a particular excipient, coating, manufacturing process, release mechanism, or branded product.

What is the legal character of the claims?

The claims are method claims under 35 U.S.C. §271(a). Direct infringement generally requires:

1. Administration of the claimed diclofenac dose;
2. For treating pain;
3. Using diclofenac acid within the claimed particle-size range;
4. In a solid oral unit dose;
5. Meeting the applicable dissolution requirement; and
6. For the narrower claims, meeting the frequency or perceptible-relief limitation.

A manufacturer does not literally practice a method claim merely by making a capsule. Liability risk increases when the product label instructs patients to use the product for pain, particularly where the label identifies the 18 mg or 35 mg dose and the product characteristics fall within the asserted limitations.

What technical features does US 8,999,387 require?

The patent requires diclofenac acid particles with a volume-average median particle size below 1,000 nm and above 25 nm. This is a submicron particle limitation. The claim does not cover all micronized diclofenac products because a formulation with a median particle size of 1,000 nm or more would fall outside the independent claims.

The dissolution test is also central:

• USP Apparatus I, basket method;
• 100 rpm;
• 37°C;
• 900 mL test medium;
• 0.05% sodium lauryl sulfate;
• Citric acid solution buffered to pH 5.75.

For the 18 mg claims, at least 94% of diclofenac acid must be released by 75 minutes. For the 35 mg claims, at least 95% must be released by 75 minutes.

Claims 6-8 and 16-18 impose more demanding release profiles by requiring the applicable percentage to be released by 60, 45, or 30 minutes.

Why the dissolution limitation matters

The dissolution limitation narrows the claim but creates an infringement and invalidity issue involving test reproducibility. A challenger would examine:

• Whether the test medium is prepared exactly as specified;
• Whether the claimed percentage is calculated against labeled dose or measured drug content;
• Whether the result is assessed per unit or as an average;
• Whether the particle-size measurement uses volume-based methodology;
• Whether agglomeration changes the measured D(50) or D(90); and
• Whether the formulation remains within the claimed profile after storage.

The patent therefore creates a combined analytical burden. A competing product must avoid either the particle-size limitation or the dissolution limitation to avoid literal infringement of the independent claims, subject to the doctrine of equivalents.

How do claims 1-24 differ?

Claims 1 and 11 are the commercial center of the patent.

18 mg claim set

Claim 1 requires:

• Treatment of pain;
• An 18 mg solid oral unit dose;
• Diclofenac acid;
• Median volume-average particle size greater than 25 nm and less than 1,000 nm; and
• At least 94% dissolution by 75 minutes.

Claims 2-4 narrow the upper particle-size limit to 900, 800, and 700 nm. Claims 6-8 accelerate the dissolution deadline. Claim 9 imposes D(90) limits. Claim 10 specifies a tablet or capsule. Claims 21 and 23 add once-daily administration and perceptible relief.

35 mg claim set

Claim 11 contains the corresponding 35 mg limitations, with a 95% dissolution threshold. Claims 12-20 parallel claims 2-10. Claims 22 and 24 add once-daily administration and perceptible relief.

The 35 mg claims are not interchangeable with the 18 mg claims. A product containing 35 mg does not infringe claim 1 merely because it meets the particle-size and dissolution requirements. Conversely, an 18 mg product does not infringe claim 11.

When does US Patent 8,999,387 lose exclusivity?

The patent's base 20-year term is generally tied to the earliest effective nonprovisional or international filing date, subject to patent-term adjustment, terminal disclaimers, patent-term extension, and any applicable disclaimer recorded with the USPTO.

Public patent records associate US 8,999,387 with a September 8, 2027 expiration date. The practical exclusivity date should be confirmed against the current USPTO Patent Center record and FDA Orange Book listing because the enforceable date can be affected by patent-term adjustment or other recorded term events.

Event	Date or status
Earliest reported priority date	September 8, 2006
Patent issued	March 31, 2015
Base term endpoint commonly reported	September 8, 2027
Patent type	Method of treatment
Relevant product	Diclofenac acid 18 mg and 35 mg oral dosage forms
Expected regulatory pathway for competitors	ANDA with Paragraph IV certification, if listed

The 2027 date is materially earlier than the expiry dates reported for certain related Zorvolex formulation or composition patents. That distinction matters because a competitor may remain exposed to other listed patents after US 8,999,387 expires.

What is the Orange Book status of US 8,999,387?

US 8,999,387 has been associated with the FDA-listed Zorvolex product and its 18 mg and 35 mg diclofenac capsules. Orange Book listing determines whether an ANDA applicant must certify to the patent under 21 U.S.C. §355(j)(2)(A)(vii).

The key regulatory questions are:

Question	Relevance
Is the patent currently listed for the applicable strength?	Determines certification obligations
Is the patent listed against 18 mg, 35 mg, or both?	Determines product-specific exposure
Is the patent listed as a method-of-use patent?	May permit a section viii statement for noninfringing labeling
Has the patent been delisted or expired?	Determines whether it can support a statutory stay
Has a Paragraph IV notice been served?	Starts potential Hatch-Waxman litigation timing

A method-of-use patent can be less effective against a generic applicant if the relevant use can be carved out of the label. That strategy depends on the scope of the approved indication and whether the patented method is inseparable from the product's labeling.

Which companies are challenging the Zorvolex patent estate?

An ANDA applicant challenging US 8,999,387 would ordinarily use one of four approaches:

1. Paragraph IV certification that the patent is invalid, unenforceable, or not infringed;
2. A section viii statement that the applicant's label omits the patented method;
3. Waiting for expiration and filing with a Paragraph III certification; or
4. Designing around the particle-size or dissolution limitations.

A Paragraph IV notice can trigger a patent infringement action under 35 U.S.C. §271(e)(2). If the NDA holder files suit within the statutory period, FDA approval can be stayed for up to 30 months, subject to statutory exceptions.

The claims supplied do not identify any particular ANDA applicant, notice letter, settlement, or court docket. The patent number itself cannot establish that a Paragraph IV challenge has occurred. A current Orange Book and PACER review is required for a definitive company-by-company litigation table.

What patent litigation affects US 8,999,387?

The principal litigation risks concern claim construction and proof of infringement.

Likely claim-construction disputes

A court could be asked to construe:

• “Containing 18 mg” and “containing 35 mg”;
• “Median particle size, on a volume average basis”;
• “Greater than 25 nm”;
• “Less than 1,000 nm”;
• “Dissolution rate of diclofenac acid”;
• “At least 94%, by weight” and “at least 95%, by weight”; and
• “Perceptible pain relief.”

The particle-size terms are especially important. D(50), median particle size, volume average, and arithmetic mean are not interchangeable measurements. A manufacturer may argue that its analytical method produces a different metric from the one required by the claim.

The dissolution limitations also create a potential evidentiary dispute. Small variations in agitation, medium preparation, sampling time, filtration, assay method, and capsule handling can affect whether the product satisfies the claimed threshold.

Validity issues

Potential validity challenges include:

• Lack of written description for the full particle-size and dissolution scope;
• Lack of enablement across all formulations within the claimed ranges;
• Obviousness based on micronized diclofenac, rapid-release NSAID formulations, and known particle-size reduction techniques;
• Indefiniteness involving “perceptible pain relief”; and
• Anticipation by prior art disclosing diclofenac acid formulations with comparable particle-size distributions and release profiles.

The narrower claims may have greater validity resilience because they require more specific particle-size and time-to-release combinations. Their narrower scope also makes design-around strategies easier.

What formulations are protected by US 8,999,387?

The patent protects solid oral formulations that satisfy the claimed performance profile, including capsules and tablets. It does not expressly require:

• A particular polymer;
• A specific wetting agent;
• A coating;
• A granulation process;
• A particular polymorph;
• A salt form other than diclofenac acid;
• A particular excipient ratio; or
• A particular manufacturing facility.

The patent therefore has broad formulation coverage within the defined dose, particle-size, and dissolution boundaries. It does not necessarily block a formulation using a different diclofenac salt, a substantially different dose, or a release profile outside the specified thresholds.

How does US 8,999,387 compare with related diclofenac patents?

Zorvolex's patent protection is best viewed as a layered estate rather than a single patent.

Protection layer	Typical subject matter	Strategic purpose
Particle-size and dissolution claims	Submicron diclofenac acid with rapid release	Targets the commercial product's performance
Composition claims	Diclofenac acid with excipients or formulation architecture	Captures the physical product
Manufacturing claims	Milling, precipitation, granulation, or processing	Creates production barriers
Method-of-use claims	Treatment of acute or chronic pain	Supports label-based enforcement
Dosage and regimen claims	18 mg, 35 mg, daily administration	Protects approved dosing patterns

US 8,999,387 is strongest when combined with composition or manufacturing patents. On its own, it may be designed around by changing particle size, altering dissolution, selecting a different salt or dosage, or omitting the patented indication from the label.

What generic entry risks exist for Zorvolex?

Generic entry risk has three stages:

Before September 2027

A generic applicant would face potential exposure from US 8,999,387 and any later-expiring related patents. A Paragraph IV challenge could accelerate entry if the patent is invalidated or found not infringed. A settlement could authorize an earlier launch date.

At expiration of US 8,999,387

Expiration removes this patent as a barrier, but it does not eliminate other Orange Book-listed patents. The commercial launch date would depend on the remaining estate, regulatory approval, 180-day exclusivity rights, litigation outcomes, and any settlement terms.

After all relevant patents expire

Competition would depend primarily on ANDA approval, manufacturing economics, substitution rules, physician prescribing, and the ability to reproduce the product's bioavailability and dissolution characteristics.

Because Zorvolex is a small-molecule drug, biosimilar rules do not apply. Competitors would use the ANDA pathway, not the biosimilar pathway under the Public Health Service Act.

What is the commercial exposure associated with this patent?

The patent is relevant to the 18 mg and 35 mg Zorvolex strengths. Its commercial value depends on:

• Sales attributable to Zorvolex;
• Whether both strengths are covered by the active Orange Book listing;
• The number of approved or pending ANDAs;
• The existence of later-expiring patents;
• Prescriber and pharmacy substitution behavior; and
• The price discount available from generic competitors.

A patent-specific revenue estimate cannot be derived from the claims alone. The claims identify the protected technical and therapeutic scope, not product sales, market share, or settlement economics.

How strong is the patent estate for US 8,999,387?

The patent has meaningful but bounded strength.

Its strengths are:

• Direct coverage of the commercial 18 mg and 35 mg strengths;
• Objective particle-size limitations;
• Objective dissolution thresholds;
• Coverage of both capsules and tablets;
• Dependent claims covering faster dissolution and narrower particle distributions; and
• Potential Orange Book relevance for ANDA applicants.

Its weaknesses are:

• The claims are method claims rather than broad composition claims;
• Infringement depends on proving use and product characteristics;
• Particle-size testing can produce methodological disputes;
• Dissolution results can vary with laboratory conditions;
• The broad independent claims may face obviousness attacks; and
• Competitors may design around one technical limitation.

Key Takeaways

• US 8,999,387 covers treatment of pain with 18 mg or 35 mg diclofenac acid solid oral doses.
• The core technical limitation is a volume-average median particle size greater than 25 nm and less than 1,000 nm.
• The 18 mg claims require at least 94% dissolution by 75 minutes; the 35 mg claims require at least 95%.
• Narrower claims require particle sizes below 900, 800, or 700 nm and faster dissolution at 60, 45, or 30 minutes.
• The patent is associated with Zorvolex and is commonly reported to expire on September 8, 2027, subject to official patent-term records.
• Generic applicants would likely use Paragraph IV, section viii, or a design-around strategy.
• The patent does not cover every diclofenac product and does not apply to biosimilar competition.
• The commercial risk must be assessed together with the remaining Zorvolex composition, formulation, manufacturing, and method-of-use patents.
• The supplied claims do not establish the identity of any challenger, litigation docket, or settlement agreement.

FAQs

Does US 8,999,387 cover diclofenac sodium?

No. The claims expressly recite diclofenac acid. A diclofenac sodium product would require a separate infringement analysis and may avoid literal infringement of the claimed active ingredient limitation.

Can a generic avoid US 8,999,387 by using particles larger than 1,000 nm?

Potentially. A formulation with a median volume-average particle size of 1,000 nm or more would not literally satisfy the independent particle-size limitation, although other patents and the doctrine of equivalents would remain relevant.

Does the patent cover injectable diclofenac?

No. The claims require a solid oral unit dose. Injectable, transdermal, topical, and other nonoral products fall outside the express dosage-form limitation.

Is a 35 mg diclofenac product covered by the 18 mg claims?

No. Claims 1-10 require an 18 mg unit dose. The 35 mg products are addressed separately in claims 11-20 and their dependents.

Can an ANDA applicant omit the patented pain indication?

Possibly, through a section viii statement if the omitted labeling avoids the patented method and the FDA-approved labeling permits the carve-out. The analysis depends on the approved indication, the patent listing, and the exact proposed label.

References

1. U.S. Patent No. 8,999,387. (2015). Methods for treating pain using diclofenac acid compositions. United States Patent and Trademark Office.

2. U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA.

3. U.S. Food and Drug Administration. (2023). Zorvolex (diclofenac) capsules prescribing information. FDA.

4. U.S. Code, 21 U.S.C. §355. Abbreviated applications and patent certifications.

5. U.S. Code, 35 U.S.C. §§271, 282, and 283. Patent infringement, validity, and remedies.

6. United States Pharmacopeial Convention. (2023). United States Pharmacopeia and National Formulary: General chapter <711>, dissolution. USP.

Drugs Protected by US Patent 8,999,387

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Zyla	ZORVOLEX	diclofenac	CAPSULE;ORAL	204592-001	Oct 18, 2013		DISCN	Yes	No	8,999,387					TREATMENT OF PAIN
Zyla	ZORVOLEX	diclofenac	CAPSULE;ORAL	204592-002	Oct 18, 2013		DISCN	Yes	No	8,999,387					TREATMENT OF PAIN

Foreign Priority and PCT Information for Patent: 8,999,387

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Australia	2009901748	Apr 24, 2009

International Family Members for US Patent 8,999,387

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
African Regional IP Organization (ARIPO)	3774
Australia	2010239080
Australia	2014208310
Brazil	PI1014272
Canada	2759123
China	102438610
China	104161743