United States Patent 10,307,368 Scope and Claims for Brimonidine Aqueous Ophthalmic Solutions With Oxy-Chloro Preservative and Carboxymethyl Cellulose

US 10,307,368 is a US patent focused on an aqueous ophthalmic composition for lowering elevated intraocular pressure in open-angle glaucoma and ocular hypertension. The claim set is narrowly anchored to a specific drug concentration (0.1% w/v brimonidine or brimonidine salt/ester), a specific preservative class (“oxy-chloro preservative”), a specific viscosity/solubilizing polymer (carboxymethyl cellulose), and a defined pH window (7.0-8.0, with dependent claims narrowing to 7.4-8.0). The estate’s enforceable perimeter is therefore most likely to concentrate on generic and authorized generics that use the same active, concentration, excipient system, and pH range, rather than on broader “brimonidine for glaucoma” use claims.

What does US 10,307,368 claim, and what is the enforceable product perimeter?

Core claim theme. The independent claim is directed to a composition for ophthalmic administration that combines:

Active: 0.1% (w/v) of brimonidine, or a brimonidine salt, or a brimonidine ester
Indication/therapeutic use: reduction of elevated intraocular pressure in open-angle glaucoma and ocular hypertension
Excipients/preservative system: includes an “oxy-chloro preservative” and carboxymethyl cellulose
pH: 7.0-8.0

Interpretation that matters for infringement. In this structure, infringement typically turns on whether an accused product matches all required claim elements:

Exact concentration: 0.1% (w/v) of brimonidine or qualifying derivatives
Specific preservative type: an “oxy-chloro preservative”
Presence of carboxymethyl cellulose
Aqueous ophthalmic formulation with pH 7.0-8.0

Even if the pH drifts slightly, or if the preservative is substituted for a different class (for example benzalkonium chloride), the composition may fall outside claim scope.

How broad are claims 1–8: which elements are limiting and which are flexible?

Claim 1 (independent).

Limiting elements (most likely):
- 0.1% (w/v) brimonidine (or salt/ester)
- oxy-chloro preservative
- carboxymethyl cellulose
- pH 7.0–8.0
Potentially flexible elements:
- The phrase “selected from the group consisting of brimonidine, a salt of brimonidine, and an ester of brimonidine” gives flexibility to the active form.
- “A therapeutically effective aqueous ophthalmic composition” implies an ophthalmic solution type and dosing form, but the claim text does not expressly require specific manufacturing steps.

Claims 2–3 (concentration narrowing or redundancy).

Claim 2 recites “about 0.1% (w/v)” brimonidine tartrate.
Claim 3 recites “0.1% (w/v)” brimonidine tartrate.
These create a two-tier hit zone: a near-0.1% formulation may read on claim 2; exact 0.1% reads on claim 3.

Claims 4–8 (excipient refinement).

Claim 4: carboxymethyl cellulose “enhances solubility” of brimonidine tartrate. This likely functions as a functional limitation tethered to CMC’s role in the formulation.
Claims 5–7: add-ons to the CMC system:
- boric acid (claim 5)
- sodium borate (claim 6)
- hydrochloric acid (claim 7)
Claim 8: narrows claim 7 by specifying pH 7.4–8.0.

Practical takeaway: claims 4–8 are narrower add-on formulations. An infringer could avoid dependent claims by changing buffer systems and pH targeting, without necessarily escaping claim 1 if claim 1’s CMC + oxy-chloro preservative + pH 7.0–8.0 and 0.1% brimonidine family elements remain present.

What does “oxy-chloro preservative” likely mean for claim coverage?

The term “oxy-chloro preservative” is the highest-risk ambiguity in claim construction because it can be interpreted as a class-based limitation. For infringement analysis, the key question becomes whether a competitor’s preservative system falls within whatever “oxy-chloro” class the patent means (for example, oxidizing chlorinated species used as preservatives).

Claim impact:

If the accused product uses an oxidizing chlorinated preservative consistent with the patent’s definition, it is more likely to meet this limitation.
If it uses a different preservative class commonly used in ophthalmics (quaternary ammonium compounds, polyquaterniums, stabilized oxyhalogen, etc.) the “oxy-chloro” classification becomes central.

Because your provided claim text does not include the specification-based definition, the enforceable scope in practice depends on the patent’s definition in the written description and claim construction record. Still, for a landscape analysis, “oxy-chloro preservative” acts as a technical barrier for substitution-based design-arounds.

How do the pH limits (7.0–8.0 and 7.4–8.0) shape design-around strategies?

Claim 1 pH window: 7.0–8.0.

A competitor aiming to avoid claim 1 could target pH outside this range, but ocular comfort and stability considerations often constrain pH selection in ophthalmic formulations.

Claim 8 pH window: 7.4–8.0.

This is narrower and only relevant if claim 7’s hydrochloric acid requirement is met. A product without HCl (or without the buffering system construed as “comprising hydrochloric acid”) may avoid claim 8 even if pH is 7.5.

Infringement mechanics:
Many ophthalmic formulations will be near-neutral to slightly basic. That increases risk of reading into the 7.0–8.0 claim 1 range unless the product is formulated to deliberately stay below 7.0 or above 8.0.

How strong is US 10,307,368 against generic brimonidine eye drops?

Strength drivers (what makes it actionable):

The claim is composition-specific and requires multiple formulation elements, reducing the risk of an overly abstract “brimonidine for glaucoma” claim.
The claim ties together active concentration, excipient class, preservative class, and pH.

Strength limits (what gives design-around opportunities):

If competitors can maintain efficacy with:
- different preservative class not treated as “oxy-chloro,” or
- different polymer system not including carboxymethyl cellulose,
- different active concentration not at (about) 0.1% or active not in the brimonidine family defined,
- pH outside the range, they could avoid the claim set without changing clinical endpoints.

Landscape implication: The patent is most likely to be highly relevant in any litigation where the accused product’s preservative system and buffering/pH are similar to the claimed formulation.

Does the patent cover method-of-treatment, and what is the scope difference vs composition claims?

The provided claims are drafted as composition claims with therapeutic use language (“for use in reduction of elevated intraocular pressure…”). That can still function as a product claim because it describes a composition intended for a therapeutic reduction of IOP. However, unlike a pure method-of-use claim, it does not require the patent owner to prove a specific administration regimen beyond “use in patients” consistent with ophthalmic delivery.

Scope consequence:

A product sold for glaucoma is likely to satisfy the therapeutic use language.
A company trying to sell the same composition under an unrelated indication would face a harder factual record, but the claim still focuses on composition elements.

What patent elements are likely to be targeted in Paragraph IV or settlement strategies?

Given the claim structure, settlements tied to US 10,307,368 would most often hinge on:

the preservative system classification (oxy-chloro vs other)
whether carboxymethyl cellulose is present as a formulation component
whether the pH lands inside 7.0–8.0
whether brimonidine tartrate is at 0.1% (w/v) (or “about 0.1%”)
whether additional buffer acids/bases are present (boric acid, sodium borate, HCl) for dependent claims

Most likely carve-out outcomes:
If a generic product uses a brimonidine 0.1% system but swaps the preservative class or eliminates CMC, it could avoid the core claim 1 read. If it keeps the same excipient system and pH, the risk rises.

Claim-by-claim mapping to formulation features (for infringement triage)

Claim	Must-have elements in an accused product (as written)	Most relevant “design-around” variables
1	Aqueous ophthalmic composition; reduces elevated IOP in open-angle glaucoma/ocular hypertension; contains 0.1% (w/v) brimonidine (or salt/ester); includes oxy-chloro preservative; includes carboxymethyl cellulose; pH 7.0–8.0	Preservative class; replace/omit CMC; shift pH outside 7.0–8.0; change concentration or active form
2	Claim 1 concept plus ~0.1% (w/v) brimonidine tartrate	Target concentration outside “about 0.1%”
3	Claim 1 concept plus 0.1% (w/v) brimonidine tartrate	Change concentration slightly or change active form away from tartrate
4	Claim 3 concept plus CMC function: “enhances solubility of brimonidine tartrate”	Functional role arguments; change polymer system or formulation design
5	Claim 3 concept plus boric acid	Buffer system substitution
6	Claim 3 concept plus sodium borate	Buffer system substitution
7	Claim 3 concept plus hydrochloric acid	Buffer acid substitution and/or omission
8	Claim 7 concept plus pH 7.4–8.0	pH targeting and acid selection

What is the likely claim construction posture in US litigation for such claims?

In a typical infringement analysis for this kind of composition patent:

Composition elements (CMC presence, active concentration, pH range, preservative class) are treated as objective technical features.
The most common disputes are:
- Whether the competitor’s preservative qualifies as “oxy-chloro” under the patent’s definition.
- Whether the product pH falls within the numeric range (including typical measurement conditions).
- Whether the polymer is carboxymethyl cellulose (and whether it is actually present at a meaningful amount).
- What qualifies as “about 0.1%” for claim 2.

If the patent specification includes examples with specific oxy-chloro preservatives (e.g., particular oxidizing systems), that will drive claim construction toward those examples.

How does US 10,307,368 compare with broader “brimonidine glaucoma” patent estates?

Compared to broad patents:
Broad estates often cover:

brimonidine dosing and treatment methods
general formulations containing brimonidine at unspecified concentrations
generic preservative systems without pH constraints

Compared to formulation-specific patents:
US 10,307,368 is closer to a “formulation with excipient system” patent:

it anchors to 0.1% concentration,
restricts the preservative class,
requires CMC,
and sets a pH band.

In practical freedom-to-operate terms, that typically means:

generic entry risk is driven by the formulation “match” rather than by the mere presence of brimonidine.

Which regulatory filings and Orange Book status would matter most?

US ophthalmic products containing brimonidine 0.1% typically appear in FDA’s listings. For 10,307,368, the relevant question for entry risk is whether an ANDA referencing the listed reference drug includes or would include:

the same preservative classification,
CMC in the formulation,
pH in the claimed numeric band.

Because the provided prompt does not include the Orange Book entry name/active/strength or the reference-listed drug, the landscape here cannot be pinned to specific listing numbers or FDA approval pathways without additional record data.

Key Takeaways

US 10,307,368 is a composition-and-formulation patent for brimonidine (or brimonidine salt/ester) at 0.1% (w/v) in an aqueous ophthalmic solution aimed at lowering elevated IOP in open-angle glaucoma and ocular hypertension.
Claim 1 is the core asset and requires a combination of:
- oxy-chloro preservative
- carboxymethyl cellulose
- pH 7.0–8.0
Claims 2–3 lock the active to brimonidine tartrate at “about 0.1%” (claim 2) and “0.1%” (claim 3), tightening infringement risk for exact concentration products.
Dependent claims add buffer chemistry (boric acid, sodium borate, hydrochloric acid) and a narrower pH band (claim 8).
Design-around leverage is highest in preservative substitution, CMC omission/replacement, and pH shifting outside 7.0–8.0, with concentration tweaks also relevant for claim 2/3.

FAQs

What formulation features must be present to infringe claim 1 of US 10,307,368?

Aqueous ophthalmic composition for elevated IOP reduction in open-angle glaucoma/ocular hypertension that includes 0.1% (w/v) brimonidine (or salt/ester), contains an oxy-chloro preservative, includes carboxymethyl cellulose, and has pH 7.0–8.0.

Does US 10,307,368 require brimonidine tartrate specifically?

No for independent claim 1. Claim 1 covers brimonidine, its salts, or esters. Claims 2–3 specify brimonidine tartrate.

Can a generic avoid the patent by using a different preservative?

Potentially yes, if the alternative preservative is not within the patent’s meaning of “oxy-chloro preservative,” while keeping other claim elements aligned.

How do claims 5–7 change infringement risk for competitors?

They add specific buffer components (boric acid, sodium borate, hydrochloric acid). A product can avoid those dependent claims by using a different buffer system or omitting those components.

Is pH outside 7.0–8.0 enough to avoid claim 1?

Yes, based on the claim’s explicit pH requirement, a product formulated outside 7.0–8.0 would not satisfy claim 1’s pH limitation.

References

US Patent 10,307,368 (claims provided in prompt).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	033539	⤷ Start Trial
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Details for Patent: 10,307,368

Summary for Patent: 10,307,368