US Patent 5,569,672: Scope, Claim Construction, Expiration, and Mupirocin Patent Landscape

US Patent 5,569,672 covers a treatment method using crystalline calcium pseudomonate, also known as mupirocin calcium, or a hydrate of that crystalline material. The claim is broad as to infection type, patient population, dosage, route, formulation, and treatment site, but narrow as to the physical form of the active ingredient. The patent issued on October 29, 1996, and its ordinary US patent term appears to have expired on October 29, 2013, subject to any applicable term adjustment or extension shown in the official patent record.[1][2]

The claim no longer creates a live US exclusionary right. Its historical importance was directed to the commercial calcium form of mupirocin used in topical antibacterial products, including Bactroban and generic mupirocin products.[3][4]

What does US Patent 5,569,672 claim?

The supplied claim recites:

"A method of treating bacterial or mycoplasmal infections of humans or non-human animals, which method comprises administering to a human or non-human animal in need thereof, an antibacterially or antimycoplasmally effective non-toxic amount of crystalline calcium pseudomonate or a hydrate thereof."

The claim has the following elements:

Claim element	Scope
Claimed subject matter	A method of treatment
Disease target	Bacterial or mycoplasmal infection
Patient	Human or non-human animal
Patient status	The subject must be "in need thereof"
Required act	Administering the active ingredient
Active ingredient	Crystalline calcium pseudomonate or a hydrate
Amount	Antibacterially or antimycoplasmally effective and non-toxic
Claim transition	"Comprises," which is generally open-ended
Express limitations absent	No specified dose, route, formulation, duration, pathogen, body site, or treatment schedule

The claim is a method-of-use claim rather than a composition, formulation, manufacturing, or product-by-process claim.

How broad is the method-of-treatment claim?

The claim is broad in therapeutic scope but form-specific.

Broad therapeutic coverage

The claim does not limit treatment to a named pathogen. It potentially covers administration for infections caused by:

Staphylococci;
Streptococci;
Other susceptible gram-positive bacteria;
Certain gram-negative bacteria;
Mycoplasma species; and
Other organisms against which mupirocin calcium has antibacterial or antimycoplasmal activity.

The claim also does not identify a particular infection site. Depending on the evidence of efficacy and the approved product labeling, the language could reach treatment of skin, nasal, wound, or other infections. A commercial product label, however, does not automatically expand the claim. Infringement analysis must connect the accused use to every claim limitation.

Broad patient coverage

The claim covers humans and non-human animals. It is not restricted to adults, pediatric patients, immunocompromised patients, hospitalized patients, or any other clinical subgroup.

The animal limitation is commercially relevant because many pharmaceutical method claims are limited to human treatment. This claim expressly extends to veterinary use.

Broad administration language

The claim contains no express limitation on:

Topical administration;
Oral administration;
Nasal administration;
Intravenous or intramuscular administration;
Cream, ointment, gel, powder, solution, suspension, or other dosage form;
Treatment concentration;
Frequency of dosing; or
Treatment duration.

The accused product must still administer crystalline calcium pseudomonate or a hydrate. A product containing only mupirocin free acid, a different salt, or a noncrystalline form would raise a substantial claim-scope issue.

Does the claim cover mupirocin calcium?

Yes. "Calcium pseudomonate" is the calcium salt form of pseudomonic acid, commercially known as mupirocin calcium. Mupirocin calcium is used in topical antibacterial products, including mupirocin calcium cream and ointment products.[3][4]

The claim's reference to crystalline material or a hydrate is significant. Commercial mupirocin calcium is commonly described as a crystalline dihydrate. The US label for Bactroban cream identifies mupirocin calcium as the active ingredient and states that it is the calcium salt of the naturally occurring antibiotic mupirocin.[3]

The claim is therefore directed at a specific solid-state form of the active pharmaceutical ingredient rather than at every possible mupirocin formulation.

What formulations are protected by US Patent 5,569,672?

The claim can potentially cover administration of crystalline calcium pseudomonate or a hydrate in multiple formulations, including:

Formulation category	Potential claim relevance
Cream	Potentially covered if it administers the claimed crystalline active
Ointment	Potentially covered if it contains the claimed form
Nasal ointment	Potentially covered if it contains crystalline calcium pseudomonate or a hydrate
Gel	Potentially covered
Powder or particulate preparation	Potentially covered
Aqueous or nonaqueous suspension	Potentially covered
Oral or parenteral formulation	Potentially within literal language, subject to safety and efficacy evidence
Free mupirocin acid formulation	Not necessarily covered
Noncalcium salt	Not necessarily covered
Amorphous calcium pseudomonate	Potentially outside literal scope

The claim does not itself require a particular excipient or delivery system. A formulation patent would ordinarily add limitations concerning ingredients, concentration, particle size, rheology, stability, packaging, or administration site. Those limitations do not appear in the supplied claim.

What is the importance of the crystalline and hydrate limitations?

The crystalline and hydrate limitations narrow the chemical scope while potentially broadening the practical relevance to commercial products.

A claim to "calcium pseudomonate" without a solid-state limitation could reach a wider range of physical forms. This claim requires:

Calcium pseudomonate;
A crystalline form or hydrate; and
Administration of that material in a qualifying treatment.

The limitation can create several design-around questions:

Whether an amorphous calcium salt falls outside the claim;
Whether a different hydrate is covered;
Whether a mixture of crystalline and amorphous material satisfies the claim;
Whether the material converts to another solid state during manufacture or storage;
Whether the marketed product contains the claimed form at the time of administration; and
Whether a generic label directs the claimed treatment.

Solid-state status is generally established through analytical techniques such as powder X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Karl Fischer water determination, and microscopy. The relevant issue is not merely whether the active ingredient is chemically mupirocin calcium, but whether the administered material meets the claimed crystalline or hydrate limitation.

When did US Patent 5,569,672 expire?

US Patent 5,569,672 issued on October 29, 1996.[1] For a patent subject to the pre-June 8, 1995 transition rules, the term is generally the greater of 17 years from grant or 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers, patent-term extension, and other statutory provisions.[2]

The ordinary 17-year term from issuance would have ended on:

Event	Date
Patent issuance	October 29, 1996
Ordinary 17-year term date	October 29, 2013
Current status for exclusivity analysis	Expired

The patent should not be treated as an active blocking right in the United States after the applicable expiration date. Patent expiration does not erase historical infringement exposure for conduct occurring before expiration, and it does not eliminate other patents covering mupirocin formulations, manufacturing processes, or specific uses.

What was the FDA and Orange Book significance?

The FDA-approved products associated with mupirocin include topical antibacterial products marketed under the Bactroban brand and later approved generic products.[3][4]

An Orange Book listing can identify patents submitted by an NDA holder for an approved drug product. A listing does not itself establish that every listed patent is valid or infringed. It provides a regulatory patent reference for abbreviated new drug application applicants.

For a generic applicant, the key regulatory pathways historically included:

Paragraph I certification, if no patent information was listed;
Paragraph II certification, if the listed patent had expired;
Paragraph III certification, with approval deferred until patent expiration; and
Paragraph IV certification, asserting that the listed patent was invalid, unenforceable, or would not be infringed.

Because US Patent 5,569,672 expired in 2013 under the ordinary term calculation, a later ANDA applicant would generally have faced a Paragraph II certification for this patent rather than a live Paragraph IV challenge. Earlier applicants could have used Paragraph IV if the patent was still listed and unexpired when the ANDA was filed.

Did US Patent 5,569,672 create generic-entry risk?

Yes, historically. The patent could have delayed or complicated generic entry involving mupirocin calcium products if the accused generic product and labeling met all limitations of the method claim.

The claim did not require a particular formulation. That increased potential reach across topical dosage forms. Its principal limiting feature was the crystalline calcium pseudomonate or hydrate requirement.

Generic-entry analysis would have focused on:

Issue	Competitive significance
Active ingredient	Whether the generic uses mupirocin calcium
Solid state	Whether the active is crystalline or hydrated
Labeling	Whether the label directs treatment of bacterial or mycoplasmal infection
Administration	Whether the product is administered to a patient
Therapeutic amount	Whether the labeled use requires an effective, nontoxic amount
Patent term	Whether the patent remained enforceable at launch
Other patents	Whether formulation, process, or use patents remained active

After expiration, this patent no longer supports an injunction against US generic launch. It may still appear in historical freedom-to-operate reviews and litigation records.

Were there Paragraph IV challenges or litigation involving the patent?

The supplied claim and patent number do not establish a particular Paragraph IV lawsuit, settlement, or named challenger. Patent litigation must be distinguished from FDA certification activity. A Paragraph IV certification may occur without a filed district-court action, and a litigation docket may involve multiple patents covering the same product.

For this patent, the key litigation issue would have been whether a generic applicant's product label induced administration of crystalline mupirocin calcium for a covered infection. Direct infringement of a method claim is ordinarily committed by the person or entity performing the claimed administration. Generic manufacturers may face induced-infringement allegations based on product labeling and promotional conduct.

The practical litigation defenses would have included:

Noninfringement because the product did not contain the claimed crystalline or hydrate form;
Noninfringement because the label did not direct a covered use;
Invalidity based on anticipation or obviousness;
Lack of enforceability;
Expiration;
Absence of a qualifying therapeutic administration; and
Adequate separation between the generic label and any patented method.

No current US enforcement risk follows from an expired patent.

How does this patent compare with formulation and manufacturing patents?

US Patent 5,569,672 is materially different from a formulation or manufacturing patent.

Patent type	Typical protected subject matter	Relationship to US 5,569,672
Method-of-use	Treating infection with crystalline calcium pseudomonate or hydrate	Direct subject matter of the claim
Composition	A formulation containing mupirocin calcium and specified excipients	Not required by the claim
Solid-state	A particular polymorph, hydrate, crystal habit, or diffraction pattern	The claim includes a broad crystalline/hydrate limitation but not detailed structural parameters
Manufacturing	Crystallization, purification, drying, or scale-up process	Not claimed in the supplied method claim
Packaging or delivery	Container, applicator, nasal device, or topical delivery system	Not required
Regulatory use	A labeled indication or patient group	Relevant to induced infringement and FDA certification

A company could avoid this expired method claim and still face a separate patent issue if another patent covered its formulation, manufacturing process, delivery device, or a narrower method of use.

How strong was the patent estate around mupirocin?

The patent estate should be analyzed as a portfolio, not through US 5,569,672 alone.

Strengths of the claimed position

Broad coverage of bacterial and mycoplasmal infections;
Coverage of both human and veterinary treatment;
No express dosage, route, formulation, or duration limitation;
Coverage of crystalline calcium pseudomonate and hydrates;
Potential relevance to multiple mupirocin calcium dosage forms.

Limitations of the claimed position

The claim is limited to a crystalline or hydrated calcium form;
It does not expressly cover mupirocin free acid;
It does not expressly claim every salt or derivative;
It requires an actual administration to a subject;
The amount must be effective and nontoxic;
The patent has expired in the United States;
Other parties could challenge validity based on prior art concerning mupirocin, calcium pseudomonate, crystalline forms, or antibacterial treatment.

The claim was commercially meaningful during its term but does not provide current US exclusivity.

What is the geographic coverage?

US Patent 5,569,672 had US territorial scope only. It could not directly block manufacture, sale, offer for sale, importation, or treatment activity outside the United States unless separate foreign counterpart patents applied.

International freedom-to-operate analysis requires review of:

European patent family members;
United Kingdom patents;
Canadian patents;
Japanese patents;
Australian patents;
Chinese patents; and
Any national-phase applications or continuations.

Foreign patent terms, claim wording, prosecution history, and expiration dates may differ. US expiration does not establish foreign expiration.

What is the current commercial impact?

The expired patent has no current US revenue exclusivity value. Its historical commercial impact was tied to mupirocin calcium products used for topical treatment of susceptible bacterial skin infections and nasal carriage or infection indications, depending on the approved product.

Current commercial exposure is more likely to arise from:

Brand-versus-generic pricing;
Supply and manufacturing capacity;
FDA product-specific requirements;
Formulation quality;
Microbiological efficacy;
Resistance concerns;
Hospital and retail contracting; and
Any separate active patents or regulatory exclusivities.

Traditional small-molecule mupirocin products do not face biosimilar approval risk. They face generic competition through the ANDA pathway. The relevant FDA framework is therefore abbreviated generic approval, not the biosimilar pathway under section 351(k) of the Public Health Service Act.

Key Takeaways

US Patent 5,569,672 claims treatment of bacterial or mycoplasmal infections with crystalline calcium pseudomonate or a hydrate.
Calcium pseudomonate is mupirocin calcium, the active salt used in commercial mupirocin products.
The claim is broad on disease, patient, route, dosage, formulation, and treatment duration.
The crystalline or hydrate limitation is the principal chemical restriction.
The patent issued October 29, 1996, and its ordinary US term ended October 29, 2013.
The patent is not a current US barrier to generic mupirocin calcium entry.
Separate formulation, solid-state, manufacturing, delivery, or method-of-use patents must be reviewed independently.
Generic applicants historically could have raised Paragraph IV issues while the patent remained listed and unexpired; after expiration, the relevant certification would generally be Paragraph II.
The patent covers treatment methods, not the manufacture or composition of every mupirocin product.
Foreign rights require separate national patent-family analysis.

FAQs About US Patent 5,569,672

Does US Patent 5,569,672 cover mupirocin ointment?

Potentially. The claim can cover administration of a mupirocin calcium ointment if the administered active is crystalline calcium pseudomonate or a hydrate and the labeled or actual use satisfies the infection-treatment limitations.

Does the patent cover mupirocin free acid?

Not clearly. The claim recites calcium pseudomonate, not mupirocin free acid. A free-acid product would require a separate infringement analysis and may fall outside the literal claim.

Can a generic manufacturer launch mupirocin calcium in the United States today?

This patent alone does not block launch because its ordinary US term expired in 2013. Other patents, FDA requirements, product-specific exclusivity, or regulatory issues could still affect a particular product.

Is calcium pseudomonate the same as mupirocin calcium dihydrate?

Calcium pseudomonate is the calcium salt of mupirocin. Commercial material may be supplied as a hydrate, including a dihydrate. Whether a specific batch meets the patent's crystalline or hydrate limitation depends on its physical and analytical characteristics.

Does the expired patent still matter in a freedom-to-operate opinion?

Yes, as historical background and for assessing pre-expiration conduct, patent-family scope, prosecution history, and related patents. It does not provide a live US exclusionary right after expiration.

References

United States Patent and Trademark Office. (1996). United States Patent No. 5,569,672.
United States Code, 35 U.S.C. §§ 154, 155, 156, 271.
U.S. Food and Drug Administration. (n.d.). Bactroban cream prescribing information.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
United Kingdom	8415579	Jun 19, 1984

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	49600	⤷ Start Trial
Australia	4373485	⤷ Start Trial
Australia	577595	⤷ Start Trial
Canada	1242437	⤷ Start Trial
Germany	3575428	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,569,672

Summary for Patent: 5,569,672