United States Patent 9,795,560: Scope, Claim Construction, Exclusivity, and Phentolamine Ophthalmic Patent Landscape

United States Patent No. 9,795,560 protects narrowly defined aqueous ophthalmic formulations containing phentolamine mesylate, a polyol or mannitol, acetate, water, and an acidic pH. The commercial center of gravity is claim 4: approximately 0.5% to 1% phentolamine mesylate, approximately 4% mannitol, approximately 3 mM sodium acetate, and a pH of 4.6 to 5.2. A product matching those parameters would present a direct literal-infringement risk unless it has a valid noninfringement or invalidity position.

The patent is directed to a formulation platform, not to phentolamine as a molecule. It does not cover every ophthalmic use of phentolamine, every dosage form, or every phentolamine formulation. Its principal value depends on whether a marketed product requires the claimed excipient system and whether later patents provide additional protection for concentration, dosing, preservation, packaging, manufacturing, or therapeutic use.

What does US Patent 9,795,560 protect?

The patent protects closed-composition aqueous ophthalmic solutions defined by ingredient identity, concentration ranges, and pH. The claims use the transitional term “consisting of,” which materially limits the claimed compositions.

Claim	Phentolamine mesylate	Polyol or mannitol	Acetate	pH	Principal scope
1	About 0.5%-2% w/v	About 1%-6% w/v mannitol, glycerol, or propylene glycol	About 1-6 mM alkali metal acetate plus acetic acid	4.5-5.5	Broadest formulation claim
2	About 0.5%-1% w/v	About 1%-6% w/v mannitol, glycerol, or propylene glycol	About 1-6 mM alkali metal acetate plus acetic acid	4.5-5.5	Narrower phentolamine range
3	About 0.25%-2% w/v	About 3%-5% mannitol	About 2-4 mM sodium acetate	4.5-5.2	Mannitol/sodium acetate formulation
4	About 0.5%-1% w/v	About 4% mannitol	About 3 mM sodium acetate	4.6-5.2	Narrow commercial formulation profile

Claims 1 and 2 expressly recite acetic acid. Claims 3 and 4 do not expressly recite acetic acid and instead require the listed composition to consist of phentolamine mesylate, mannitol, sodium acetate, and water. That difference is important. A formulation containing separately added acetic acid may fall within claims 1 or 2 but could create a claim-construction dispute under claims 3 and 4, depending on how the complete specification and prosecution history treat pH adjustment and residual components.

How should the claims be construed?

What does “consisting of” mean in this patent?

“Consisting of” generally excludes unrecited ingredients that materially alter the basic and novel characteristics of the claimed composition. It ordinarily permits incidental impurities, residual processing materials, and components that do not materially change the claimed formulation, but it creates substantially less freedom than “comprising.” The relevant infringement analysis must examine the final commercial product, not only the manufacturing bill of materials. (35 U.S.C. § 112; MPEP § 2111.03.)

A product containing a preservative, surfactant, chelating agent, viscosity modifier, additional buffer, or other functional excipient could raise a noninfringement argument under the closed transition. The argument would depend on whether the additional ingredient is material to the formulation’s basic and novel characteristics. Adding an ingredient does not automatically avoid infringement.

How do the concentration ranges operate?

The claims use approximate ranges. A formulation at 0.5% phentolamine mesylate, 4% mannitol, 3 mM sodium acetate, and pH 4.8 would be within claim 4. A formulation at 0.49% phentolamine mesylate may still create infringement exposure if “about” encompasses the measured value. The specification, examples, analytical precision, manufacturing tolerances, and prosecution record would control the practical boundary.

A formulation outside a numerical range can still raise a doctrine-of-equivalents issue if the difference is insubstantial and the limitation was not surrendered during prosecution. The doctrine cannot, however, eliminate a claim limitation or recapture subject matter surrendered to obtain allowance. (Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17 (1997); Festo Corp. v. Shoketsu Kinzoku Kogyo Co., 535 U.S. 722 (2002).)

What is the strongest claim in US 9,795,560?

Claim 4 is the narrowest and most commercially targeted claim. Its limitations map closely to a conventional low-dose phentolamine ophthalmic formulation:

0.5%-1% w/v phentolamine mesylate;
approximately 4% mannitol;
approximately 3 mM sodium acetate;
water; and
pH 4.6-5.2.

Claim 1 has the broadest literal reach because it covers three polyols and a wider phentolamine range. Claims 2 and 3 provide intermediate fallback positions. From an enforcement perspective, claim 4 may be easier to prove against a product whose label, regulatory filing, or formulation dossier discloses the precise composition. From a validity perspective, claims 1 and 2 may face a broader prior-art field because they cover multiple polyols and wider concentration ranges.

Commercial characteristic	Claim 1	Claim 3	Claim 4
Polyol flexibility	Mannitol, glycerol, or propylene glycol	Mannitol only	Mannitol only
Acetate flexibility	Any alkali metal acetate	Sodium acetate only	Sodium acetate only
Buffer components	Acetate plus acetic acid	No express acetic acid limitation	No express acetic acid limitation
Concentration precision	Broad	Moderate	High
Likely design-around difficulty	Moderate	Higher	Highest if product uses same target composition

What formulations are protected by the patent?

The protected formulation space includes aqueous ophthalmic solutions with acidic pH and an osmotic or tonicity-adjusting polyol.

Claim 1 formulation space

Claim 1 covers phentolamine mesylate at approximately 0.5%-2% w/v, one or more of mannitol, glycerol, and propylene glycol at approximately 1%-6% w/v, and approximately 1-6 mM of an alkali metal acetate. It also requires acetic acid and a pH between 4.5 and 5.5.

Potentially covered alkali metal acetates include sodium acetate and potassium acetate, subject to the claim language and specification. The claim does not require mannitol if glycerol or propylene glycol is used.

Claim 2 formulation space

Claim 2 narrows phentolamine mesylate to approximately 0.5%-1% w/v. It retains the three-polyol alternative and the acetate/acetic-acid requirement. This claim is particularly relevant to a low-dose product in the range commonly associated with phentolamine ophthalmic development.

Claim 3 formulation space

Claim 3 requires mannitol and sodium acetate. It narrows the mannitol range to approximately 3%-5% and sodium acetate to approximately 2-4 mM, while allowing phentolamine mesylate from approximately 0.25%-2%. The pH range is 4.5-5.2.

Claim 4 formulation space

Claim 4 is limited to approximately 4% mannitol and approximately 3 mM sodium acetate. The phentolamine range is approximately 0.5%-1%, and the pH range is 4.6-5.2. This claim has limited numerical breadth but can be commercially important because small formulation changes may not avoid the claim if they remain within the scope of “about.”

When does US 9,795,560 lose exclusivity?

US Patent 9,795,560 issued on October 24, 2017. The patent’s enforceable term is generally calculated from the earliest effective nonprovisional U.S. filing date, subject to patent-term adjustment, terminal disclaimers, and any applicable patent-term extension. The grant date alone does not establish the expiration date. (35 U.S.C. §§ 154, 156.)

The claims supplied do not disclose the earliest priority date, patent-term adjustment, or terminal-disclaimer status. A precise expiration date cannot be established from the claim text alone. The controlling sources are the front page and continuity data for US 9,795,560, the USPTO Patent Center file history, and any applicable terminal-disclaimer or patent-term records.

The patent may also be relevant after regulatory exclusivity expires. FDA drug exclusivity and patent term are separate rights. A generic applicant may submit an ANDA before patent expiry with a Paragraph IV certification, while commercial launch remains subject to litigation, settlement terms, injunctions, and the outcome of the patent challenge. (21 U.S.C. § 355(j); 21 C.F.R. § 314.107.)

What is the Orange Book status of US 9,795,560?

Patent listing in the Orange Book is not automatic for every formulation patent. A patent must be submitted for listing in connection with an approved drug application and must satisfy FDA’s listing criteria. A formulation patent may be listed when it claims the approved drug, an approved formulation or composition, or an approved method of use, subject to FDA’s regulations. (FDA, 2023.)

If the relevant phentolamine ophthalmic product does not have an approved NDA, there is no Orange Book-listed product patent for that product. If an NDA is approved, the patent holder or NDA sponsor may submit the patent for listing, and the FDA’s current Orange Book must be checked for the actual listing status.

US 9,795,560 should therefore be separated into two questions:

Whether the patent is legally enforceable as a U.S. patent.
Whether it is listed against a specific approved phentolamine ophthalmic product in the Orange Book.

The first question is determined by USPTO and court records. The second is determined by FDA Orange Book records.

Does the patent create biosimilar risk?

No. Phentolamine mesylate is a small-molecule active ingredient. The relevant competitive pathway is an ANDA for a generic drug, not a 351(k) biosimilar application. A generic applicant would typically assess:

pharmaceutical equivalence;
bioequivalence;
inactive-ingredient differences;
formulation and manufacturing patents;
method-of-use patents;
Orange Book listings; and
Paragraph IV certification exposure.

The patent does not block all generic phentolamine products. It targets a particular aqueous ophthalmic formulation. A generic developer could pursue a formulation outside one or more claim limitations, subject to equivalence risk and other patents.

Which design-arounds are most plausible?

Potential design-around strategies include changing one or more of the following:

Design variable	Possible design-around direction	Principal risk
Polyol	Replace mannitol with another tonicity agent	Claims 1 and 2 still cover glycerol or propylene glycol
Mannitol level	Use a concentration outside approximately 3%-5% or approximately 4%	“About” and equivalence risk
Acetate	Use another buffer system	Other patents or regulatory comparability issues
Sodium acetate	Use potassium acetate or another permitted acetate	Claim 1 may still cover another alkali metal acetate
pH	Move outside 4.5-5.5	Product stability, tolerability, and equivalence issues
Phentolamine concentration	Use a concentration below 0.5% or above 1%	Claim 3 reaches approximately 0.25%-2%
Composition	Add a functional excipient	Closed-composition claim and materiality analysis

The cleanest literal design-around would generally require moving outside the pH, active-ingredient, polyol, and acetate limitations simultaneously enough to avoid the “about” boundaries. A one-variable change may not be sufficient.

What patent litigation and Paragraph IV risks exist?

A Paragraph IV challenge would likely attack one or more of the following:

Written description and enablement for the claimed concentration combinations.
Obviousness based on known phentolamine ophthalmic solutions, buffer systems, tonicity agents, and pH ranges.
Anticipation by a prior-art formulation containing the claimed ingredients and ranges.
Indefiniteness concerning “about,” “one or more,” and the meaning of “consisting of.”
Claim construction concerning acetic acid in claims 1 and 2 versus claims 3 and 4.
The commercial product’s actual composition, including manufacturing tolerances and pH adjustment materials.

A generic applicant would not need to prove that every claim is invalid. It would need to establish a basis for noninfringement, invalidity, or both. The patent owner could file a Hatch-Waxman action within the statutory period after receiving notice of a Paragraph IV certification, potentially triggering a 30-month stay of FDA approval under the conditions specified in the statute. (21 U.S.C. § 355(j)(5)(B)(iii).)

No settlement terms, launch date, or court disposition can be determined from the claim text alone. Settlement agreements in ANDA litigation may include delayed-entry dates, authorized-generic arrangements, or licensing provisions, and may materially alter the commercial impact of the patent.

How does US 9,795,560 compare with other phentolamine patents?

US 9,795,560 is a composition patent. A complete freedom-to-operate review for a phentolamine ophthalmic product must also identify:

later continuation and divisional patents;
concentration-specific claims;
method-of-use claims for presbyopia, dim-light vision, night vision, or other indications;
dosing-regimen claims;
preservative-free container and packaging claims;
manufacturing and sterilization claims;
stability claims;
crystalline, salt, or polymorph claims; and
international equivalents.

A formulation patent may be commercially important even when the active ingredient is old. The relevant estate is the cumulative set of issued and pending claims, not US 9,795,560 in isolation. Continuation applications can preserve prosecution leverage after the original patent issues, while later patents may extend protection to commercial features not covered by the original claims.

What is the commercial exposure for a competing product?

A product that uses approximately 0.75% phentolamine mesylate, 4% mannitol, 3 mM sodium acetate, water, and an acidic pH around 4.8 would fall squarely within claim 4 on the supplied language. Such a product would also likely fall within claim 3 and, depending on the presence of acetic acid and the precise pH, claims 1 and 2.

The commercial exposure has four components:

patent infringement risk from the formulation;
regulatory delay from a Paragraph IV dispute;
reformulation cost and clinical bridging requirements;
settlement or license economics.

Revenue exposure cannot be quantified without the approved product, market size, launch date, price, and competing-product assumptions. The formulation claim is most consequential where the sponsor’s clinical and regulatory package is built around the claimed composition and a substitute formulation would require new stability, tolerability, or clinical work.

Key Takeaways

US 9,795,560 claims aqueous ophthalmic phentolamine mesylate formulations, not phentolamine generally.
Claim 4 is the most commercially targeted claim and covers approximately 0.5%-1% phentolamine mesylate, 4% mannitol, 3 mM sodium acetate, and pH 4.6-5.2.
Claims 1 and 2 are broader because they cover mannitol, glycerol, or propylene glycol and a wider phentolamine range.
The “consisting of” language limits additional ingredients and creates a central claim-construction issue for preserved or otherwise modified products.
Claims 3 and 4 do not expressly recite acetic acid, unlike claims 1 and 2.
The patent is relevant to ANDA and Paragraph IV strategy, not biosimilar strategy.
A precise patent expiration date requires the patent’s priority, continuity, patent-term-adjustment, and terminal-disclaimer records.
Orange Book listing must be assessed against the specific approved NDA and cannot be inferred from the patent claims.
Later continuation, method-of-use, formulation, manufacturing, and packaging patents may provide broader commercial protection than this patent alone.

FAQs About US Patent 9,795,560

Does US 9,795,560 cover a 0.75% phentolamine ophthalmic solution?

Yes, a 0.75% solution can fall within claims 1, 2, 3, and 4 if the polyol, acetate, water, and pH limitations are also satisfied.

Can a product avoid the patent by replacing mannitol with glycerol?

Not necessarily. Claims 1 and 2 expressly cover glycerol and propylene glycol as alternatives to mannitol.

Does adding a preservative automatically avoid infringement?

No. The claims use “consisting of,” but an additional ingredient avoids infringement only if it is legally excluded under the claim construction or materially changes the claimed composition. The analysis depends on the ingredient and the patent record.

Is phentolamine ophthalmic subject to biosimilar competition?

No. Phentolamine is a small molecule. Competition would proceed through the ANDA generic-drug pathway rather than the biosimilar pathway.

Can a generic launch before the patent expires?

A generic applicant may seek approval before expiry through an ANDA and Paragraph IV certification. Commercial launch may still be blocked by litigation, a statutory stay, an injunction, a settlement, or other enforceable patent rights.

References

35 U.S.C. §§ 112, 154, 156.
21 U.S.C. § 355(j).
21 C.F.R. § 314.107.
FDA. (2023). Approved drug products with therapeutic equivalence evaluations. U.S. Food and Drug Administration.
U.S. Patent No. 9,795,560. (2017). Ophthalmic compositions containing phentolamine.
U.S. Patent and Trademark Office. (2024). Manual of Patent Examining Procedure, §§ 2111, 2111.03.
Festo Corp. v. Shoketsu Kinzoku Kogyo Co., 535 U.S. 722 (2002).
Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U.S. 17 (1997).

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Famygen Life Sci	RYZUMVI	phentolamine mesylate	SOLUTION;OPHTHALMIC	217064-001	Sep 25, 2023		RX	Yes	Yes	9,795,560	⤷ Start Trial	Y				⤷ 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

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2014212274	⤷ Start Trial
Australia	2018200566	⤷ Start Trial
Canada	2899339	⤷ Start Trial
Denmark	2950648	⤷ Start Trial
European Patent Office	2950648	⤷ Start Trial
Spain	2762153	⤷ Start Trial
Japan	2016506966	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,795,560

Which drugs does patent 9,795,560 protect, and when does it expire?

Summary for Patent: 9,795,560