US Patent 5,843,930 (United States): Scope, Claim Breakdown, and US Landscape
US Patent 5,843,930 is a method-of-treatment claim directed to otitis using a specific topical otic formulation. The scope is narrow in formulation composition and broad only to the extent it covers “introducing” the composition for antibacterial and anti-inflammatory treatment of otitis. The claim’s novelty hinges on a defined combination of ciprofloxacin, a non-ionic, pH/ionic-insensitive viscosity augmenter that is at least 85% hydrolyzed polyvinyl alcohol (PVA), a non-ototoxic preservative (benzyl alcohol), hydrocortisone suspension, lecithin, and polysorbate (20 to 80) for spreading.
What is the core claimed invention in US 5,843,930?
Claim type and trigger
- Claim 1 is a method of treating otitis by introducing a topical otic composition to the ear.
- The therapeutic effect is defined by components that support:
- Antibacterial action from ciprofloxacin
- Anti-inflammatory action from hydrocortisone
- Non-ototoxicity from preservative and formulation constraints
Claim scope in one sentence (business framing)
The claim covers treatment of otitis where the administered otic composition is an aqueous, topical formulation containing ciprofloxacin + hydrocortisone + benzyl alcohol + lecithin + non-ionic viscosity augmenter that is at least 85% hydrolyzed PVA + polysorbate (20-80), with functional limits on antibacterial, anti-inflammatory, viscosity, spreading, and preservative safety.
How does Claim 1 define the formulation scope? (Element-by-element)
Claim 1 requires every listed component and multiple “purpose” constraints. Below is the claim language mapped into enforceable scope elements.
A. Antibacterial active
- Ciprofloxacin in aqueous solution
- Amount must be “effective for antibacterial action”
Scope effect: Any accused formulation must include ciprofloxacin at a level that meets antibacterial effectiveness as used in the ear context. This is typically litigated as a functional limit, which can be satisfied by concentration ranges disclosed or known effective dosing.
B. Viscosity augmenter with strict identity and performance constraints
- Non-ionic viscosity augmenter
- Unaffected by pH and ionic level
- Present at an amount effective to augment viscosity to greater than water
- Identity: “at least 85% hydrolyzed polyvinyl alcohol”
Scope effect: The viscosity agent is a key narrowing feature. The claim is not satisfied by generic thickeners unless they are:
- Non-ionic
- Unchanged across pH/ionic strength
- At least 85% hydrolyzed PVA
This element is often the main axis for design-around.
C. Preservative safety constraint
- Non-ototoxic preservative
- Amount effective for antibacterial action
- Identity: benzyl alcohol
Scope effect: Substitution of benzyl alcohol with another preservative can avoid literal scope unless doctrine of equivalents applies. The “non-ototoxic” feature adds factual complexity, but the identity is still fixed: benzyl alcohol.
D. Aqueous vehicle
- Water sufficient to produce an aqueous composition
Scope effect: Establishes a topical aqueous otic formulation, not an emulsion oil phase or solvent system.
E. Anti-inflammatory component
- Hydrocortisone in aqueous suspension
- Amount effective for anti-inflammatory action
Scope effect: Requires hydrocortisone as a suspension (not a fully dissolved solution, at least as claimed). Partial dissolved formulations may still be argued as “suspension” depending on particle state and formulation behavior.
F. Suspension aid / stabilizer
- Lecithin
- Amount effective for enhancing suspension of other constituents
Scope effect: Lecithin is a required excipient. Substitution can be a design-around if the accused formulation lacks lecithin or uses a fundamentally different suspension system.
G. Spreading agent range
- Polysorbate ranging from polysorbate 20 to 80
- Amount effective for spreading on a hydrophobic skin surface to the site of infection or inflammation
Scope effect: Claim requires polysorbate within the 20 to 80 family. In practice, the issue becomes whether the accused product’s surfactant is polysorbate of the claimed range and whether it is “effective for spreading” for otic application.
What is the enforceable scope: literal coverage vs functional coverage?
Literal (hard identity constraints)
A competitor’s product avoids Claim 1 most cleanly by removing or changing any of the following required identities:
- Ciprofloxacin (active)
- Non-ionic viscosity augmenter that is at least 85% hydrolyzed PVA
- Benzyl alcohol (preservative)
- Hydrocortisone (anti-inflammatory)
- Lecithin
- Polysorbate (20 to 80)
Functional limits that may be litigated
These do not specify numerical concentration ranges in the claim excerpt you provided, so they are functional:
- “effective for antibacterial action” (ciprofloxacin)
- viscosity > water and unaffected by pH/ionic level (PVA performance)
- “non-ototoxic” benzyl alcohol
- “effective for anti-inflammatory action” (hydrocortisone)
- “effective for enhancing suspension” (lecithin)
- “effective for spreading” (polysorbate)
Functional language can still be enforced, but it drives disputes into formulation measurements, biological effects, and expert testimony.
Where is the claim broad, and where is it narrow?
Narrowing features (high design-around value)
- Identity of the thickener: at least 85% hydrolyzed PVA and non-ionic and pH/ionic-insensitive
- Fixed preservative identity: benzyl alcohol
- Fixed combination of actives and excipients: ciprofloxacin + hydrocortisone + lecithin + polysorbate 20-80
- Suspension form: hydrocortisone in aqueous suspension
Broadening features (limited but present)
- The claim does not recite specific concentration numeric ranges.
- “effective amount” language means a range of concentrations can fall within scope if performance is met.
- “introducing” and “treating otitis” covers clinical modalities that administer a topical otic formulation to treat otitis, without specifying a particular administration frequency.
How would an accused product be evaluated against this claim? (Practical claim chart structure)
A valid infringement analysis for US 5,843,930 Claim 1 typically proceeds as follows:
1) Is the drug ciprofloxacin?
- If no ciprofloxacin: no literal infringement on Claim 1.
2) Does it contain a non-ionic viscosity augmenter that is at least 85% hydrolyzed PVA?
- If the viscosity system is a different polymer, a blend without meeting “at least 85% hydrolyzed PVA,” or a non-PVA thickener: likely design-around.
- If it is PVA but not “unaffected by pH and ionic level”: potential non-literal arguments, depending on formulation behavior.
3) Is benzyl alcohol present as the non-ototoxic preservative?
- If preservative is swapped away from benzyl alcohol: strong non-infringement position.
4) Does it contain hydrocortisone in suspension form?
- If hydrocortisone is absent or fully dissolved: likely avoids the claim.
5) Does it contain lecithin as suspension enhancer?
- If lecithin is absent and suspension is engineered with other excipients: likely avoids literal scope.
6) Is polysorbate present within the 20 to 80 range?
- If surfactant system is not polysorbate (or is outside the 20-80 species range): likely avoids literal scope.
7) Does the method context match “treating otitis” by introducing the formulation?
- The claim is method-of-treatment. The product must be introduced to treat otitis.
US patent landscape: how to position 5,843,930 against likely competitor classes
Because the claim you provided is highly formulation-specific, the relevant landscape is not driven by general otic antibiotic patents alone. It is driven by (i) combination otic products and (ii) specific formulation excipient systems (viscosity, preservatives, suspending agents, and surfactant spreading systems).
A. “Combination products” landscape axis
Your claim pairs:
- Fluoroquinolone antibiotic (ciprofloxacin) with
- Corticosteroid anti-inflammatory (hydrocortisone)
This places the patent within the high-activity area of ear therapeutics where products combine antibiotic and steroid to treat otitis while controlling inflammation.
Landscape implication: Many competitor products cover the same therapeutic indication but with different formulation scaffolds. Under Claim 1, the combination actives alone are not enough; the excipient system must match.
B. “Formulation excipient” landscape axis (the real battleground)
Claim 1 is particularly constrained by:
- 85%+ hydrolyzed PVA and non-ionic behavior independent of ionic strength/pH
- benzyl alcohol as non-ototoxic preservative
- lecithin for suspension
- polysorbate 20-80 for spreading
Landscape implication: A competitor can pursue the same actives with alternative excipients and potentially avoid Claim 1 even if it has a similar clinical outcome.
C. “Design-around strategy” map
For a generic or follow-on formulation to avoid Claim 1 while maintaining therapeutic effect, likely routes are:
- Swap benzyl alcohol for a different preservative system
- Replace at least 85% hydrolyzed PVA with a different viscosity polymer or a different hydrolysis grade not meeting the “at least 85%” limitation
- Use a non-polysorbate surfactant system or polysorbate outside the claimed range
- Eliminate lecithin and use a different suspension enhancer
What does the claim require procedurally: method of treating otitis
The method is tied to “introducing” the composition. That language typically means:
- The formulation is administered in vivo to treat otitis.
- The claim is not limited to a particular dosing regimen in the excerpt provided.
- It does not specify which ear (external ear vs middle ear) beyond “otic” and “hydrophobic skin surface,” suggesting topical coverage.
Key Takeaways
- US 5,843,930 Claim 1 is a combination otic method anchored to a specific aqueous topical formulation.
- The claim’s main enforceability lever is excipient identity, not just the actives:
- Non-ionic viscosity augmenter must be at least 85% hydrolyzed PVA and remain effective across pH/ionic conditions.
- Benzyl alcohol is a required non-ototoxic preservative identity.
- Lecithin and polysorbate (20 to 80) are also required, with functional roles.
- Design-around is most viable by changing PVA (identity/grade/performance), benzyl alcohol, lecithin, or polysorbate, while potentially retaining the general therapeutic goal of treating otitis.
FAQs
1) Does US 5,843,930 cover any ciprofloxacin + hydrocortisone ear product?
No. Claim 1 requires additional excipients and functional constraints, including at least 85% hydrolyzed PVA, benzyl alcohol, lecithin, and polysorbate (20 to 80).
2) What excipient is the strongest design-around target?
The viscosity augmenter requirement: it must be non-ionic and at least 85% hydrolyzed polyvinyl alcohol with pH/ionic insensitivity and viscosity above water.
3) If a product uses a different preservative but matches the rest, does it avoid Claim 1?
It avoids literal scope if it is not benzyl alcohol as the required non-ototoxic preservative. Under Claim 1, benzyl alcohol is an explicit element.
4) Can hydrocortisone be dissolved instead of suspended?
Claim 1 requires hydrocortisone in aqueous suspension, so a dissolved formulation likely falls outside literal scope.
5) What does “polysorbate ranging from polysorbate 20 to 80” mean for infringement?
It limits the surfactant identity to polysorbate species spanning polysorbate 20 through 80 as claimed; substitution with non-polysorbate surfactants or different polysorbate coverage can avoid literal scope.
References
[1] United States Patent US 5,843,930, Claim 1 (as provided by user).
