United States Patent 5,965,549: Scope, Claims, Expiration, and Patent Landscape for Ciprofloxacin-Hydrocortisone Otic Compositions

U.S. Patent 5,965,549 covers a specific aqueous otic formulation combining ciprofloxacin, hydrocortisone, highly hydrolyzed polyvinyl alcohol, benzyl alcohol, lecithin, and polysorbate. The patent is associated with the Cipro HC Otic product concept. Its term has expired, eliminating the patent as a current U.S. exclusion right. The claims remain relevant for historical product identification, freedom-to-operate analysis, patent-family research, and assessment of formulation design-arounds.

The principal claim is narrow in composition but broad in functional language. It requires all seven core components in an aqueous, non-ototoxic topical otic composition. A product omitting one required component would not literally infringe claim 1, subject to any applicable doctrine-of-equivalents analysis.

What does U.S. Patent 5,965,549 protect?

The patent protects an aqueous otic composition containing:

Ciprofloxacin or a pharmaceutically acceptable salt.
Hydrocortisone or a pharmaceutically acceptable salt.
Polyvinyl alcohol that is at least about 85% hydrolyzed.
Water.
Benzyl alcohol.
Lecithin.
A polysorbate, apparently polysorbate 20 through polysorbate 80.

The claimed formulation is designed to deliver both antibacterial and anti-inflammatory activity while maintaining hydrocortisone in suspension and spreading the preparation across hydrophobic tissue surfaces.

The patent does not claim ciprofloxacin and hydrocortisone as a broad therapeutic combination without formulation limitations. It requires the excipient system and the stated functional attributes.

What product is associated with the patent?

Cipro HC Otic contains ciprofloxacin hydrochloride and hydrocortisone in an aqueous otic suspension. The FDA labeling identifies the formulation as a sterile suspension for topical use in the ear. The labeled strengths are approximately 0.2% ciprofloxacin, expressed as ciprofloxacin hydrochloride, and 1% hydrocortisone. The labeled excipients include polyvinyl alcohol, lecithin, polysorbate 20, benzyl alcohol, sodium chloride, and acetate-related buffering components.[2]

The commercial formulation falls within the concentration ranges recited in dependent claims 2 through 9.

How broad is claim 1 of U.S. Patent 5,965,549?

Claim 1 is a composition-of-matter claim drafted with “consisting essentially of” language. This creates a closed formulation boundary for components that materially affect the invention, while potentially allowing additional ingredients that do not materially alter the claimed suspension, spreading, antibacterial, anti-inflammatory, or otic-safety characteristics.

Claim 1 element analysis

Claim element	Scope	Commercial significance
Aqueous composition	Requires water-based formulation	Excludes anhydrous ointments and nonaqueous delivery systems
Non-ototoxic	Functional safety limitation	Could create proof issues because ototoxicity is not defined by a numerical threshold in the claim
Topical otic use	Requires ear-directed topical pharmaceutical use	A dermatological or ophthalmic product may fall outside literal scope
Ciprofloxacin	Active antibacterial agent	Salts are expressly included
Hydrocortisone	Corticosteroid anti-inflammatory	Salts are expressly included
Polyvinyl alcohol, at least 85% hydrolyzed	Suspension aid with structural limitation	Substitution with another polymer is a potential design-around
Benzyl alcohol	Preservative or antibacterial component	Its omission may avoid literal infringement
Lecithin	Suspension-enhancing excipient	A formulation using a different suspending system may avoid the claim
Polysorbate 20 to 80	Spreading and wetting agent	The specific polysorbate grade matters
“Effective” amounts	Functional amount limitations	Ordinary formulation ranges may satisfy the limitations even if percentages differ

The claim requires the components to perform stated functions. A formulation containing trace amounts of an ingredient may not satisfy the claim if the ingredient does not perform the claimed function. Conversely, a formulation can potentially satisfy the claim even if its concentrations differ from the commercial product, provided the ingredients perform the specified functions.

Effect of “consisting essentially of”

The phrase “consisting essentially of” generally permits additional components unless they materially affect the basic and novel characteristics of the claimed composition. The relevant characteristics appear to include:

Suspension of hydrocortisone in an aqueous system.
Spreading on hydrophobic tissue.
Antibacterial activity.
Anti-inflammatory activity.
Non-ototoxic topical use.

An accused formulation containing an additional viscosity modifier, buffer, chelator, preservative, or tonicity agent would not automatically escape the claim. The legal question would be whether the added ingredient materially changes the identified characteristics.

What do claims 2 through 10 add?

The dependent claims narrow claim 1 through concentration, buffer, salt, and polymer-hydrolysis limitations.

Claim	Added limitation	Practical effect
2	Ciprofloxacin at 0.01% to 1.0% by weight	Covers the commercial 0.2% strength
3	Hydrocortisone at 0.1% to 3.0% by weight	Covers the commercial 1% strength
4	Polyvinyl alcohol at 0.1% to 10.0% by weight	Captures ordinary suspension-agent levels
5	Lecithin at 0.01% to 5.0% by weight	Covers low-to-moderate lecithin levels
6	Benzyl alcohol at 0.1% to 3.0% by weight	Covers typical preservative concentrations
7	Acetate buffer at approximately 0.05 molar	Targets the disclosed buffer system
8	Polysorbate at 0.01% to 2.0% by weight	Captures typical surfactant levels
9	Sodium chloride at 0.1% to 5.0% by weight	Adds tonicity control
10	Polyvinyl alcohol at least 99% hydrolyzed	Narrows the polymer requirement

A product that satisfies claim 10 necessarily satisfies the hydrolysis threshold in claim 1, but it must still contain the other claim 1 components. Claims 7 and 9 are narrower because claim 1 does not require acetate buffer or sodium chloride.

The claim text supplied includes the phrase “polysorbate ranging from 20polysorbate 20 to 80.” That wording appears to contain a transcription or formatting defect. The issued patent text, certified patent copy, and prosecution history control the interpretation. The most plausible intended scope is polysorbate 20 through polysorbate 80, but the precise claim language should be confirmed against the official record before relying on the range in litigation or an invalidity opinion.

When did U.S. Patent 5,965,549 expire?

U.S. Patent 5,965,549 is no longer enforceable. The patent issued on October 12, 1999. Its ordinary patent term ran from the applicable nonprovisional filing date, subject to any patent-term adjustment or other statutory adjustment reflected in the USPTO record.[1]

Public drug-patent records identify the patent as having expired in 2017. The expiration date associated with the Cipro HC Otic patent listing is September 11, 2017.[3] The patent therefore does not create a current U.S. barrier to generic manufacture, sale, or approval.

Exclusivity timeline

Event	Date or status
U.S. patent issued	October 12, 1999
Cipro HC Otic FDA approval	2003, according to FDA product labeling
Patent associated with product	U.S. 5,965,549
Patent expiration reported in Orange Book-related records	September 11, 2017
Current patent enforceability	Expired
Current Paragraph IV significance	Historical only, absent a separate unexpired patent

Patent expiration does not eliminate regulatory requirements. A prospective manufacturer still needs an approved NDA, ANDA, or other legally appropriate FDA pathway, together with adequate product quality, bioequivalence, stability, microbiological, and otic-safety data.

What is the Orange Book status of Cipro HC Otic?

Cipro HC Otic was approved under NDA 21-836 for topical otic treatment. The Orange Book listed U.S. Patent 5,965,549 in connection with the product.[3]

The listing was relevant during the patent term because an ANDA applicant could have needed to address the patent through a Paragraph III certification, Paragraph IV certification, or another applicable certification under the Hatch-Waxman framework. After patent expiration, the listed patent no longer blocks approval or commercial launch.

FDA approval of an ANDA does not itself establish that every formulation is outside an expired patent. The practical issue now is different: because the patent has expired, a formulation meeting the claims may be used without prospective patent infringement liability in the United States, provided no other unexpired intellectual-property right applies.

Were there Paragraph IV challenges or settlements?

The available patent and product records do not establish a current Paragraph IV dispute involving U.S. 5,965,549. Any Paragraph IV challenge would have been commercially relevant before the patent’s expiration. After September 11, 2017, a Paragraph IV certification to this patent would generally have little or no standalone blocking effect because the patent term has ended.

A historical Paragraph IV filing could still matter for:

180-day exclusivity analysis.
Prior generic-entry timing.
Settlement economics.
Litigation history.
Commercial launch sequencing.

The patent itself should not be treated as an active litigation asset. Any present litigation risk would have to arise from a separate patent, trademark, regulatory exclusivity, trade-secret right, or product-specific issue.

How strong was the patent estate?

The estate was moderately strong against close copies during its term but weak against materially different formulation architectures.

Strengths

The patent combined the active ingredients with a defined excipient system. A close copy using:

Ciprofloxacin hydrochloride;
1% hydrocortisone;
Polyvinyl alcohol;
Lecithin;
Benzyl alcohol;
Polysorbate 20; and
An aqueous otic vehicle

would have faced substantial literal-infringement risk if the functional limitations were met.

The dependent claims also captured the commercial concentration profile. That alignment reduced the value of simple concentration changes as a design-around.

Weaknesses

The claims contain several potentially contestable limitations:

“Non-ototoxic” is functional and lacks an express numerical test.
“Effective for antibacterial action” and “effective as an anti-inflammatory agent” are functional phrases.
“Effective to suspend” and “effective for spreading” may require technical evidence.
The claim uses “consisting essentially of,” which can generate disputes over added ingredients.
The polysorbate wording in the supplied text appears defective.
The patent does not broadly cover all ciprofloxacin-corticosteroid otic products.
The patent does not appear to cover unrelated delivery platforms such as gels, ointments, microspheres, liposomes, or dry powders unless they fall within the aqueous composition language.

Because the patent is expired, these weaknesses now have historical rather than exclusionary significance.

What formulations are protected by the patent?

The strongest historical coverage is for formulations close to the labeled Cipro HC Otic composition.

Likely covered formulation profile

A formulation would have presented a high literal-infringement risk during the patent term if it included:

Ciprofloxacin at about 0.2%;
Hydrocortisone at about 1%;
Polyvinyl alcohol, at least 85% hydrolyzed;
Lecithin;
Benzyl alcohol;
Polysorbate 20;
Water;
Sodium chloride;
Acetate buffering; and
Otic topical administration.

Claims 2 through 9 specifically reinforce that commercial profile.

Potential design-around routes

A historical design-around could have pursued one or more of the following:

Replace hydrocortisone with dexamethasone, fluocinolone, or another corticosteroid.
Replace ciprofloxacin with ofloxacin, levofloxacin, or another antibacterial agent.
Omit lecithin and use a different suspension technology.
Replace polyvinyl alcohol with a different polymer or structured vehicle.
Use a different surfactant instead of polysorbate.
Use an ointment, gel, or nonaqueous delivery system.
Develop separate active-ingredient products rather than a fixed combination.
Use a different preservative system without benzyl alcohol.

The most commercially important competitive product is Ciprodex, which combines ciprofloxacin with dexamethasone rather than hydrocortisone. That active-steroid substitution places the product outside the literal scope of claim 1, although separate patents and regulatory protections must be analyzed independently.[4]

How does the patent compare with competing otic products?

Product or product type	Antibacterial	Steroid	Key distinction from U.S. 5,965,549
Cipro HC Otic	Ciprofloxacin	Hydrocortisone	Closest formulation and product association
Ciprodex	Ciprofloxacin	Dexamethasone	Different corticosteroid
Ofloxacin otic	Ofloxacin	None	Different antibacterial and no steroid
Neomycin/polymyxin B/hydrocortisone products	Neomycin and polymyxin B	Hydrocortisone	Different antibacterial system
Generic ciprofloxacin/hydrocortisone suspension	Ciprofloxacin	Hydrocortisone	Could historically have required a patent analysis; patent now expired

The competitive threat to a ciprofloxacin-hydrocortisone product is not limited to an exact generic. Substitution by ciprofloxacin-dexamethasone, ofloxacin, or nonsteroidal otic products can reduce the commercial value of the claimed combination.

Does the patent create biosimilar risk?

No. U.S. Patent 5,965,549 covers a small-molecule drug product, not a biologic. Biosimilar statutes and the Biologics Price Competition and Innovation Act do not apply. The relevant competitors are generic-drug applicants, authorized generics, branded reformulations, and therapeutic substitutes.

What manufacturing and intellectual-property barriers remain?

The expired patent does not impose a current manufacturing barrier. A manufacturer must still address:

Ciprofloxacin hydrochloride sourcing and impurity control.
Hydrocortisone particle size and suspension stability.
Polyvinyl alcohol hydrolysis level and molecular-weight distribution.
Uniformity of suspended corticosteroid particles.
Preservative effectiveness.
Sterility or microbial-control requirements appropriate to the product.
Container-closure compatibility.
Shake-before-use performance.
Sedimentation and redispersion.
Otic tolerability and local safety.
Bioequivalence or other FDA approval requirements.

The patent claims are formulation claims, not broad manufacturing-process claims. They do not appear, based on the claim set provided, to monopolize a particular mixing sequence, sterilization process, filling process, particle-size distribution, or container system.

Separate process patents, know-how, supplier agreements, regulatory exclusivity, trademarks, and trade secrets could still affect market entry. Those rights are not established by U.S. 5,965,549 itself.

What patent litigation affects Cipro HC Otic?

U.S. 5,965,549 is expired, so it cannot support a new U.S. infringement action based on post-expiration conduct. Historical litigation could have concerned generic filing activity, Paragraph IV certification, claim construction, validity, or settlement terms. The patent number alone does not establish the existence or outcome of a particular lawsuit.

A current litigation review should distinguish:

Patent cases filed before expiration.
Cases dismissed after settlement.
Cases involving other Cipro HC Otic patents.
Product-liability or regulatory cases.
Trademark and unfair-competition disputes.
Foreign proceedings involving counterpart patents.

The expired status is the controlling fact for present freedom to operate under this patent.

What is the commercial exposure associated with the patent?

The patent was commercially important because it protected the formulation underlying a branded otic product rather than merely one active ingredient. Its expiration opened the possibility of generic substitution and price erosion.

The principal exposure categories were:

Exposure category	Effect of expiration
Exact generic copy	Patent barrier removed
Ciprofloxacin-hydrocortisone suspension	Increased competition risk
Ciprofloxacin-dexamethasone substitution	Separate competitive pressure
Ofloxacin and other otic products	Therapeutic substitution
Authorized generic strategy	Potential branded-price defense
Formulation improvement patent	Must be analyzed separately
Regulatory exclusivity	Must be checked independently from patent term

No revenue figure should be attributed to the patent without product-level sales data. The patent protected a formulation, not all ciprofloxacin otic sales or all steroid-antibiotic ear treatments.

Key Takeaways

U.S. Patent 5,965,549 covers an aqueous ciprofloxacin-hydrocortisone otic composition with polyvinyl alcohol, benzyl alcohol, lecithin, and polysorbate.
Claim 1 is narrower than a general ciprofloxacin-plus-hydrocortisone combination claim because it requires the specified excipient system and functional characteristics.
Claims 2 through 9 capture concentration ranges closely aligned with the Cipro HC Otic commercial formulation.
Claim 10 narrows the polyvinyl alcohol requirement to at least 99% hydrolysis.
The patent expired in 2017, with September 11, 2017 reported as the relevant expiration date.
The patent is not a current U.S. barrier to generic launch.
No biosimilar pathway is relevant because the product is a small-molecule drug.
A close copy would have faced meaningful historical infringement risk, but alternative steroids, suspension systems, surfactants, preservatives, or delivery vehicles offered potential design-around routes.
Current market-entry analysis must focus on FDA requirements and any separate unexpired patents, regulatory rights, trademarks, or trade secrets.

FAQs

Can a generic manufacturer now copy the Cipro HC Otic formulation?

The expired patent no longer prohibits copying the claimed formulation in the United States. FDA approval, product quality, bioequivalence, and other regulatory requirements remain applicable.

Does using dexamethasone instead of hydrocortisone avoid U.S. Patent 5,965,549?

Yes, substitution of dexamethasone for hydrocortisone would avoid the literal hydrocortisone limitation in claim 1. Separate patent and regulatory analyses would still be required.

Is U.S. Patent 5,965,549 a process patent?

No. The supplied claims are composition claims. They do not claim a specific manufacturing sequence or filling process.

Does the patent cover all ciprofloxacin otic products?

No. It covers a defined ciprofloxacin-hydrocortisone aqueous composition with the recited excipients and functional attributes. Ciprofloxacin-only products and products using different corticosteroids generally fall outside the literal claim scope.

Can a formulation omit lecithin and remain outside the patent?

Omission of lecithin would avoid literal infringement of claim 1 because lecithin is a required element. A doctrine-of-equivalents analysis could have been relevant during the patent term, but the patent is now expired.

References

United States Patent and Trademark Office. (1999). U.S. Patent No. 5,965,549, Otic pharmaceutical composition.
U.S. Food and Drug Administration. (n.d.). Cipro HC Otic prescribing information.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations (Orange Book), Cipro HC Otic, NDA 21-836.
U.S. Food and Drug Administration. (n.d.). Ciprodex prescribing information.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	214931	⤷ Start Trial
Australia	5984096	⤷ Start Trial
Australia	708540	⤷ Start Trial
Canada	2199294	⤷ Start Trial
China	1137685	⤷ Start Trial
China	1160999	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,965,549

Summary for Patent: 5,965,549