United States Patent 10,278,918 (Ophthalmic Phentolamine + Polyol Aqueous Solution): Scope, Claim Architecture, and Landscape
United States Drug Patent US 10,278,918 is directed to an aqueous ophthalmic solution containing phentolamine (or a pharmaceutically acceptable salt) plus a defined polyol excipient system and a defined buffer and pH window, with optional excipients selected from a broad ophthalmic formulation palette. The claim set is built around a core composition claim (claim 1), then narrows through polyol identity, concentration, buffer concentration/identity, and pH ranges, with a secondary composition “consists of” embodiment (claim 14) and further concentration-specification dependent claims.
What is the core claim scope in US 10,278,918?
Claim 1: Composition and parameter envelope
Claim 1 claims an aqueous ophthalmic solution defined by concentration ranges and pH, structured as:
- Phentolamine component (active):
- About 0.1% (w/v) to about 4% (w/v) of phentolamine or a pharmaceutically acceptable salt
- Polyol component (excipient):
- About 1% (w/v) to about 6% (w/v) of at least one polyol selected from:
mannitol, glycerol, propylene glycol, ethylene glycol, sorbitol, xylitol
- Buffer component:
- About 0.1 mM to about 10 mM of at least one buffer
- Water:
- Optional excipients:
- optionally one or more of: poly(C2-4alkylene)glycol polymer, dextran, cellulose agent, carbohydrate, alkali metal halide, alkaline earth metal halide, boric acid, cyclodextrin, dextrose, glycerin, urea, viscosity modifying agent, solubilizing agent, surfactant, demulcent polymer, wetting agent, water-miscible solvent
- pH limitation:
This is a parameter-driven claim. Infringement is triggered by meeting the recited composition constraints, regardless of the optional excipient selection (so long as the core recited categories and ranges are satisfied).
Claim 1’s practical meaning
- The active is constrained but broad enough for multiple formulation strengths (0.1% to 4% w/v).
- The polyol system is a second major determinant, with a wide excipient concentration span (1% to 6% w/v) and multiple allowable polyol identities.
- The buffer is relatively permissive on identity (“at least one buffer”) but fixed on concentration (0.1 to 10 mM).
- The pH window (4.0 to 7.5) is broad and may capture many buffered ophthalmic formulations.
How are the dependent claims narrowing the scope?
Polyol identity and concentration narrowing
The dependent claim chain repeatedly narrows the polyol element, using identity and specific percentage windows:
- Claim 2: at least one polyol is mannitol
- Claim 3: polyol is 2% (w/v) to 5% (w/v)
- Claim 4: polyol is 3.5% (w/v) to 4.5% (w/v)
- Claim 5: polyol is about 4% (w/v)
This creates a layered claim surface: a generic mannitol-containing option (claim 2) and then increasingly specific mannitol percentage embodiments (claims 3 to 5).
Buffer concentration and identity
Buffer narrowing is implemented through both concentration and salt identity:
- Claim 6: buffer concentration 2 mM to 4 mM
- Claim 7: buffer concentration about 3 mM
- Claim 8: buffer comprises alkali metal acetate
- Claim 9: buffer comprises sodium acetate
Notably, claims 8 and 9 restrict buffer chemistry to acetate (and specifically sodium acetate), while claims 6 and 7 restrict concentration.
pH narrowing
The dependent claims further constrain the pH range:
- Claim 10: pH 4.5 to 6.0
- Claim 11: pH 4.7 to 5.1
This places a narrower band inside the broader claim 1 pH 4.0 to 7.5.
Phentolamine strength narrowing
The dependent claims also narrow active strength:
- Claim 12: phentolamine content 0.5% (w/v) to 2% (w/v)
- Claim 13: phentolamine content about 1% (w/v)
“Consists of” subset embodiment (secondary independent-style claim)
Claim 14 recites a narrower “consists of” version that limits what is included in the formulation category list:
- About 0.25% (w/v) to about 2% (w/v) of phentolamine mesylate
- About 1% (w/v) to about 6% (w/v) polyol from the same set (mannitol, glycerol, propylene glycol, ethylene glycol, sorbitol, xylitol)
- About 0.1 mM to about 10 mM buffer
- water
- optionally a narrower subset of optional excipients compared with claim 1:
poly(C2-4alkylene)glycol polymer, dextran, alkali metal halide, alkaline earth metal halide, boric acid, cyclodextrin, dextrose, glycerin, urea, surfactant, demulcent polymer
(claim 14 excludes some of claim 1 optional categories such as cellulose agent, carbohydrate, viscosity modifying agent, solubilizing agent, wetting agent, water-miscible solvent)
Then claim 14 is followed by dependent claims specifying further narrowing:
- Claim 15: phentolamine mesylate 0.25% to 1% (w/v)
- Claim 16: phentolamine mesylate about 1% (w/v)
- Claim 17: polyol 3.5% (w/v) to 4.5% (w/v)
- Claim 18: buffer comprises alkali metal acetate
- Claim 19: buffer comprises sodium acetate
- Claim 20: buffer concentration 2 mM to 4 mM
- Claim 21: pH 4.5 to 6.0
- Claim 22: phentolamine mesylate 0.25% to 2% (w/v)
- Claim 23: phentolamine mesylate about 1% (w/v)
Claim 14 changes the “escape space” for design-arounds
Claim 1 allows optional excipients from a broad set. Claim 14 limits the optional list. Practically, if a competitor’s formulation includes an excipient that falls within claim 1’s optional set but not claim 14’s optional set, they may still fall under claim 1 but could avoid claim 14 if “consists of” limitations become decisive.
What is the patent’s infringement “hit matrix” for a competitor?
A competitor’s ophthalmic solution would more likely risk infringement if it simultaneously meets:
- Active: phentolamine or salt in the relevant range
- Polyol: one of the enumerated polyols at the required concentration
- Buffer: a buffered aqueous system at the required buffer concentration
- pH: in the claimed pH band (broad in claim 1, narrower in dependents)
- Optional excipient footprint: only relevant if claim 14’s “consists of” embodiment is asserted
Key numeric envelopes embedded in the claim set
| Element |
Claim 1 envelope |
Narrowing dependents (examples) |
| Phentolamine (or salt) |
~0.1% to ~4% (w/v) |
~0.5% to ~2% (c12); ~1% (c13) |
| Polyol identity |
at least one: mannitol, glycerol, propylene glycol, ethylene glycol, sorbitol, xylitol |
mannitol only (c2) |
| Polyol concentration |
~1% to ~6% (w/v) |
~2% to ~5% (c3); ~3.5% to ~4.5% (c4); ~4% (c5) |
| Buffer concentration |
~0.1 mM to ~10 mM |
~2 to ~4 mM (c6); ~3 mM (c7) |
| Buffer identity |
any buffer (minimum constraint) |
alkali metal acetate (c8); sodium acetate (c9) |
| pH |
4.0 to 7.5 |
4.5 to 6.0 (c10); 4.7 to 5.1 (c11) |
| “Consists of” embodiment |
N/A (claim 1 is “consisting of” + optional) |
claim 14 uses phentolamine mesylate and restricts optional excipient list |
How broad is the claim coverage compared with the “consists of” subset?
Claim 1: broader optional-excipient latitude
Claim 1’s optional excipient list is expansive, including categories that are common in ophthalmic solutions (viscosity modifying agents, solubilizing agents, wetting agents, water-miscible solvents). That breadth means many competitor formulations that keep the core active/polyol/buffer/pH structure will still land inside claim 1 even if they use additional ophthalmic components.
Claim 14: narrower optional-excipient latitude
Claim 14 narrows the optional list. That matters in two ways:
- It can reduce the set of formulations that satisfy claim 14 if a competitor uses certain excipients not enumerated in claim 14’s optional set.
- It does not remove the broader risk under claim 1, because claim 1 already provides optional latitude.
Net: claim 1 is the bigger barrier; claim 14 is a more specific pathway often used for asserting stronger composition fit.
What does the claim set imply for likely patent landscape positioning?
The claim architecture signals this patent is positioned as a formulation patent covering an aqueous ophthalmic solution using:
- Phentolamine as the active for an ophthalmic use case (the claims do not recite the condition, but the product is explicitly “ophthalmic”).
- A polyol excipient system, including mannitol (a dominant ophthalmic tonicity/viscosity adjunct), with multiple other compatible polyols.
- Buffering in the mM range and a mildly acidic to near-neutral pH band.
Landscape patterns typical for this type of claim
Within formulation-focused patent portfolios, the frequent landscape outcome is:
- Many competing formulations are “close” because they share common components (aqueous buffer, mannitol, acetate, pH around 5).
- Differences shift to (a) whether the active is the same chemical form/salt, (b) whether polyol concentration or identity matches, (c) pH and buffer molarity, and (d) excipient inclusion relative to “consists of” constraints.
This claim set gives multiple independent levers for either (1) enforcing on a specific target formulation band, or (2) designing around by breaking one of the major numeric constraints.
Where are the most important design-around “fault lines”?
Fault line 1: polyol concentration and identity
Claim 1 allows wide polyol ranges and multiple polyols. But dependent claims create sharper “trap” ranges:
- ~3.5% to ~4.5% polyol and ~4% polyol are specifically called out (claims 4 and 5, and claim 17 for claim 14 embodiment).
Breaking polyol concentration outside these ranges can reduce exposure to dependent claims, but claim 1 still remains broad.
Fault line 2: pH
Claim 1 covers 4.0 to 7.5. Dependent claims carve out 4.5 to 6.0 and 4.7 to 5.1. A competitor can target a pH outside the dependent windows, but must ensure it remains outside the pH windows asserted (and also note claim 1 still captures many pH choices within 4.0 to 7.5).
Fault line 3: buffer concentration and acetate salts
If sodium acetate or alkali metal acetate at ~2 to ~4 mM or ~3 mM is used, dependent claims 6 to 9 and 18 to 20 become more relevant. A competitor can shift to a different buffer system or outside those concentration windows, though again claim 1 does not require acetate identity.
Fault line 4: active as “phentolamine mesylate”
Claim 14 is explicitly about phentolamine mesylate. If a competitor uses a different phentolamine salt form, they can potentially avoid claim 14 while still risking claim 1 if they use phentolamine broadly.
What is the scope outcome if a competitor matches the “typical target” formulation band?
The most defensible view from the claim set is that a formulation that is roughly:
- ~1% phentolamine (or mesylate)
- ~4% mannitol
- ~3 mM sodium acetate
- pH ~5.0
would fall neatly into multiple dependent claim layers at once:
- active: claims 13, 16, 23
- polyol: claims 2, 4, 5, 17
- buffer: claims 7, 9
- pH: claims 10, 11, 21
That stacking is exactly the claim design: it supports enforcement against a commonly desirable formulation “center” rather than only a single corner.
Key Takeaways
- US 10,278,918 claims an aqueous ophthalmic solution with phentolamine (or salt) plus polyol excipients and a buffered system, limited by concentration ranges and pH 4.0 to 7.5 in claim 1.
- Claim 1 is the primary scope driver because it includes a broad set of optional excipients and allows multiple polyol identities and wide concentration ranges.
- Dependent claims narrow to high-likelihood formulation subsets, especially:
- mannitol as the polyol,
- ~3.5% to 4.5% (and ~4%) polyol,
- acetate buffer (especially sodium acetate),
- ~2 to 4 mM (and ~3 mM) buffer,
- pH 4.5 to 6.0 and 4.7 to 5.1.
- Claim 14 is a narrower “consists of” subset centered on phentolamine mesylate and a reduced optional-excipient list; it can be harder to satisfy if a competitor’s formulation uses excipients not listed in claim 14, but it does not remove exposure under claim 1.
- The claim set creates multiple “fault lines” for design-around: polyol identity/concentration, pH, buffer molarity and acetate identity, and salt form for claim 14.
FAQs
1) Does claim 1 require a specific buffer identity?
No. Claim 1 requires about 0.1 mM to about 10 mM of at least one buffer, without limiting the buffer identity; dependent claims specify alkali metal acetate and sodium acetate.
2) Is mannitol mandatory to practice the invention?
No. Mannitol is only required if dependent claim 2 (and related narrowing dependent claims tied to mannitol concentration bands) is implicated. Claim 1 allows multiple polyols.
3) What is the primary pH risk range for enforcement?
Claim 1 is pH 4.0 to 7.5, while dependent claims narrow to 4.5 to 6.0 and 4.7 to 5.1.
4) How does using phentolamine mesylate change risk?
It aligns with claim 14, which explicitly recites phentolamine mesylate and a more limited optional excipient set. It does not eliminate claim 1 risk.
5) Can a competitor avoid claim 14 without avoiding claim 1?
Yes. If the competitor uses an active/salt and optional excipients that do not satisfy claim 14’s “consists of” optional-excipient list, they may avoid claim 14 while still potentially meeting claim 1’s broader optional excipient allowance.
References (APA)
[1] US 10,278,918. (n.d.). United States patent application/US patent for an aqueous ophthalmic solution containing phentolamine and polyol with specified buffer and pH ranges.
