United States Patent 9,044,484 (Brimonidine Multi-Dose Ophthalmic Composition): Scope, Claim Boundaries, and US Patent Landscape
Executive summary: US Patent 9,044,484 claims a multi-dose ophthalmic composition centered on brimonidine, formulated to meet specific polyol/borate/BAC concentration windows, pH limits, and (in dependent claims) preservative efficacy, tear pH buffering resistance, and suspension performance. The claim set is narrow in the selected excipient types and numeric ranges, but can still be meaningful for “work-alike” formulations that match the same preservative system (BAC-only) and buffering/tear pH resistance profile.
What are the key active-ingredient and excipient elements in US 9,044,484 claim 1?
Claim 1 is the core independent claim. It ties together: (i) an alpha-2 agonist, (ii) a specific two-polyol system, (iii) borate, (iv) benzalkonium chloride (BAC) at a defined range, and (v) a controlled pH window.
Required composition components (Claim 1)
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Therapeutic brimonidine
- “A therapeutically effective amount of brimonidine.”
- No numeric dose stated in Claim 1 text you provided.
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First polyol (mannitol and/or sorbitol) with concentration limits
- Selected from: mannitol, sorbitol, or combinations
- Concentration: ≥ 0.15 w/v % but < 0.5 w/v %
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Second polyol (propylene glycol and/or glycerine) with concentration limits
- Selected from: propylene glycol, glycerine, or combinations
- Concentration: ≥ 0.3 w/v % but < 1.2 w/v %
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Borate
- Concentration: ≥ 0.1 w/v % but < ~0.5 w/v %
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Preservative system
- BAC (benzalkonium chloride) as an anti-microbial preservative
- Concentration: > 0.0007 w/v % but < 0.0035 w/v %
- This is a relatively tight band that is likely engineered for preservative efficacy while controlling ocular tolerability.
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Water
- Standard ophthalmic aqueous base.
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pH window
- Composition pH: ≥ 4 but < 7.0
Claim 1 enforceability profile
What specific performance and test results limit Claim 2 (preservative efficacy and time-kill)?
Claim 2 depends on Claim 1 and adds quantitative preservative efficacy requirements.
Microbial inoculum reduction criteria (Claim 2)
Scope note
- Claim 2 is the type of limitation that can be powerful in litigation because it functions as a functional/empirical barrier. If a formulation is tested and fails the log reduction schedule, it may be outside the claim even if it otherwise matches excipient ranges.
How do the dependent claims narrow polyol concentration “sub-windows” (Claims 3 and 4)?
Claim 3: tighter first polyol concentration
- First polyol (from mannitol/sorbitol): ≥ 0.25 w/v % but < ~0.35 w/v %
This is a meaningful narrowing relative to Claim 1’s broader 0.15–<0.5.
Claim 4: tighter BAC range
Claim 5: even tighter BAC range
These dependent claims create a ladder:
- broader Claim 1: >0.0007 and <0.0035
- narrower Claim 4/5: under 0.0025 or under 0.0015
- while still anchored to the BAC requirement.
What formulation variants are explicitly called out (Claims 6, 7, 9, 10–12, 13, 14, 15–19, 20–23)?
Claim 6: specific polyol pairing
- First polyol = mannitol
- Second polyol = propylene glycol
This likely matters for competitors choosing between glycerine vs propylene glycol, or sorbitol vs mannitol.
Claim 7: preservative restriction
- “Substantially free of any preservatives other than BAC”
- This supports an argument that additional preservatives may avoid infringement unless “substantially free” is interpreted broadly.
Claim 8: tear pH buffering resistance metric
- “Resistance provided … to normalization of tear pH after instillation…”
- Threshold: < 25 μl of 1 M NaOH/mL of composition
This is a functional ocular tolerability proxy. It sets a quantitative barrier for tear alkalinization.
Claim 9: optional combination with brinzolamide
- Adds: “therapeutically effective amount of brinzolamide.”
So the patent is not strictly limited to brimonidine-only products. It extends to combination therapies, at least where all Claim 1 limitations remain satisfied.
Claims 10–12: anionic polymer and suspension
- Claim 10: includes “anionic polymer”
- Claim 11: polymer selected from xanthan gum or carboxyvinyl polymer
- Claim 12: “suspension … with a therapeutic agent suspended”
This implies the patent addresses not only solutions but also suspension dosage forms.
Claim 13: excludes anti-infectives/antibiotics
- “Free of any anti-infective or anti-biotic ophthalmic drug.”
Claim 14: redispersibility
- “redispersed with no more than 15 seconds of vigorous shaking”
This is another functional performance anchor.
What are the “suspension + viscosity + redispersion + BAC-only + pH” clusters in Claims 15–19?
Claim 15: broader independent successor version within the claim set
Your text’s Claim 15 is effectively a second independent claim block with the same theme:
- brimonidine
- first polyol (mannitol/sorbitol) in 0.15–0.5
- second polyol (propylene glycol/glycerine) in ≥0.3–<1.2
- borate ≥0.1–<0.5
- BAC-only preservation (free of any preservatives other than BAC)
- pH ≥4 to <7
- and includes anionic polymer
- plus the suspension/vehicle requirements (as written).
Claim 16: tighter tear pH resistance
Claim 17: viscosity window and shear-rate measurement
- Suspension viscosity: >20 cps but <500 cps
- Measured at high shear rate of sec−1 at room temperature (your text omits a specific shear value; the claim still ties to “high shear rate” testing).
Claim 18: shorter redispersion time
- No more than 15 seconds shaking (same threshold as Claim 14 as written, but it appears in this dependent chain too).
Claim 19: excludes anti-infectives/antibiotics
- “free of any anti-infective or anti-biotic ophthalmic drug.”
How do Claims 20–21 expand use and chronic glaucoma indication scope?
Claim 20: dosing frequency and chronic administration
- Composition configured for repeated administration for an “extend period of time”
- “administered at least once a week”
- patient eye disorder diagnosed as suitably treated with chronic administration
Claim 21: elevated intraocular pressure
- Disorder = elevated intraocular pressure
This is an indication/method-of-use style limitation, even though the claim language is composition-focused (“configured for administration”) and tied to chronic use.
What are the specific concentration combinations in Claim 22 (borate, polymer, and multiple numeric gates)?
Claim 22 is a tightly constrained composition variant. It requires:
- Brimonidine
- First polyol: mannitol 0.15–0.5
- Second polyol: propylene glycol 0.3–1.2
- Borate: ≥0.25 w/v % but < ~0.35 w/v %
- Anionic polymer: carboxyvinyl polymer 0.1–<1.2 w/v %
- BAC: >0.0007 w/v % but <0.0035 w/v %
- Preservative restriction: free of any preservatives other than BAC
- Tear pH resistance: <15 μl of 1 M NaOH/mL
- Suspension: agent suspended in solution
- Viscosity: >20 cps and <500 (high shear, room temperature)
- Free of anti-infective/antibiotic ophthalmic drug
- pH: ≥4 but <7.0
Claim 23
- “wherein the therapeutic agent in brinzolamide” (as written in your text; it reads like an additional narrowing when used as a combination product).
How broad is the patent estate for this “brimonidine + BAC + polyol/borate + pH” formulation concept in the US?
In US Patent 9,044,484 itself, the claim coverage is moderately narrow because:
- BAC is required.
- borate is required.
- the formulation must sit within tight excipient and pH windows.
- several dependent claims add further gating via microbial kill thresholds, tear pH resistance, and viscosity/redispersion performance.
Without the full US prosecution history, family member data, and the rest of the patents listed in the same publication families, a complete landscape cannot be reconstructed from claim text alone. The provided text is limited to claim language for a single US patent, and does not include:
- priority dates
- patent assignee(s)
- citation lists
- related continuations/divisionals
- Orange Book listings
- FDA label and application numbers
- any co-owned patents for brimonidine/brinzolamide formulations.
Given the constraint that only complete and accurate responses should be produced, no further US-wide quantitative landscape (counts by family, expiration calendars, or Paragraph IV risk mapping) is generated here.
Key claim boundaries that drive freedom-to-operate (FTO) for alternatives
1) BAC-only requirement and anti-infective/antibiotic exclusion
- If a competitor uses another antimicrobial system or adds additional anti-infectives/antibiotics, Claim 7/15/22-type “BAC-only” and “free of anti-infective/antibiotic ophthalmic drug” constraints may be avoided.
2) Polyol identity and concentration windows
- First polyol is limited to mannitol and/or sorbitol; second polyol to propylene glycol and/or glycerine.
- A competitor could design around by swapping to other osmotically active agents (not covered in your claim text) or using concentrations outside the ranges.
3) Borate inclusion window
- Borate must be in a numeric band. Many formulations instead use citrate/phosphate buffering or other systems, and would likely fall outside Claim 1 and its tighter dependent claims (like Claim 22’s 0.25–<0.35).
4) pH constraints
- pH must be at least 4 but below 7.0.
- Tear alkalinization resistance metrics (Claims 8 and 16) add additional design constraints beyond pH alone.
5) Suspension requirements
- Dependent chains introduce anionic polymers (xanthan gum, carboxyvinyl polymer), viscosity gates, and redispersion timing.
- A solution dosage form rather than a suspension can become a major non-infringing axis if it doesn’t meet suspension/polymer/viscosity/redispersion limitations.
Timeline and patent-life questions
This section requires priority date(s), grant date, and family/continuation status to determine:
- regulatory exclusivity overlap
- patent expiration
- expected generic/biosimilar dates
- Paragraph IV windowing
Those inputs are not provided in the prompt, so a complete and accurate exclusivity and expiration timeline cannot be produced.
Key Takeaways
- US 9,044,484 Claim 1 is anchored on brimonidine with a two-polyol (mannitol/sorbitol + propylene glycol/glycerine) system, borate, and BAC within tight numeric ranges, plus a defined pH window.
- Claim 2 adds preservative efficacy constraints using log-reduction/time-kill style thresholds.
- Dependent claims narrow further using tighter polyol and BAC ranges, plus quantitative tear pH buffering resistance.
- The later dependent chain expands into anionic polymer-containing suspensions with viscosity and redispersion time constraints.
- Several dependent claims include combination therapy (brinzolamide) and chronic glaucoma-relevant use anchored on elevated intraocular pressure.
FAQs
1) What excipient types are mandatory in US 9,044,484 and which ones are optional?
Mannitol/sorbitol (first polyol), propylene glycol/glycerine (second polyol), borate, BAC, water are built into Claim 1. Anionic polymer and suspension attributes are introduced by dependent claims.
2) Does using an additional preservative besides BAC automatically avoid infringement?
The dependent claim language includes “substantially free” or “free of any preservatives other than BAC,” creating a design-around path if additional preservatives are used and if “free/substantially free” is construed narrowly.
3) How do the tear pH resistance limits affect formulation design?
Claims 8 and 16 impose numeric thresholds (<25 μl or <15 μl of 1 M NaOH/mL), which are independent functional constraints beyond the pH range.
4) Can a solution dosage form infringe a claim that recites viscosity and redispersion after shaking?
If the claim depends on suspension-specific elements (anionic polymer + viscosity window + redispersion), a solution that lacks those characteristics is a common non-infringing direction under claim construction.
5) How does the brinzolamide combination appear in the patent scope?
Brinzolamide is introduced in dependent claim form (Claim 9 and referenced again in Claim 23 text), so a product must still satisfy Claim 1’s formulation elements to fall within those dependent claims.
References (APA)
- United States Patent 9,044,484. (Claims provided in user prompt).
