US Patent 7,728,143: Delafloxacin Meglumine Crystal Forms, Processes, and Patent Landscape

US Patent 7,728,143 protects specific solid forms of delafloxacin meglumine, including the trihydrate, an anhydrous or lower-hydration crystalline form identified by PXRD, dehydration and recrystallization processes, and products made by those processes. It does not claim delafloxacin broadly, the antibacterial method of treatment, intravenous or oral formulations as such, or every salt or polymorph of delafloxacin.

The patent is directed to the active pharmaceutical ingredient in Baxdela, delafloxacin meglumine. The principal commercial risk is form-specific: a competing manufacturer could avoid literal infringement by using a different salt, polymorph, hydrate state, or manufacturing route, subject to equivalence and patent-family coverage.

What drug and chemical entity does US 7,728,143 cover?

The claimed compound is delafloxacin meglumine, also called delafloxacin meglumine hydrate. Delafloxacin is a fluoroquinolone antibacterial containing a chlorinated quinolone core, a difluoropyridinyl substituent, and a 3-hydroxyazetidinyl substituent. Meglumine, or N-methyl-D-glucamine, forms the salt with the quinolone carboxylic acid.

Item	Description
Active ingredient	Delafloxacin
Salt former	Meglumine, or N-methyl-D-glucamine
Commercial product	Baxdela
Dosage forms	Oral tablets and intravenous injection
NDA holder and original developer	Melinta Therapeutics and predecessor companies
FDA approval	June 19, 2017
Therapeutic class	Fluoroquinolone antibacterial
Patent at issue	US 7,728,143
Primary subject matter	Delafloxacin meglumine solid forms and preparation processes

The long chemical name in the claims identifies the meglumine salt rather than a separate antibacterial molecule. Claim 1 is the clearest composition claim because it expressly recites the trihydrate salt.

What are the claims of US 7,728,143?

Claim 1: Delafloxacin meglumine trihydrate

Claim 1 covers the chemical compound itself in trihydrate salt form. It is not limited to a particular PXRD profile, particle size, solvent, batch scale, or manufacturing process.

Its practical scope includes a product containing the claimed delafloxacin meglumine trihydrate, provided the accused material satisfies the chemical and hydration limitations. A product sold under a different name or produced by a different process could still fall within the claim.

Claim 1 is the strongest composition claim in the patent because it does not depend on a process limitation or a figure-based analytical limitation.

Claim 2: Crystalline delafloxacin meglumine identified by PXRD

Claim 2 covers a crystalline salt characterized by the powder X-ray diffraction pattern shown in Figure 1, measured at approximately 25°C with Cu-Kα radiation.

This is a structure-by-characterization claim. The claim does not depend solely on the chemical formula. The accused material must also exhibit the specified diffraction pattern, subject to the ordinary legal analysis of claim construction and analytical variation.

The claim appears directed to a crystalline form distinct from the trihydrate expressly recited in Claims 1 and 3. The exact hydration state should be determined from the specification and Figure 1, rather than inferred solely from the claim text.

Claim 3: Crystalline delafloxacin meglumine trihydrate identified by PXRD

Claim 3 covers the trihydrate crystalline form characterized by the PXRD pattern in Figure 2.

This claim is narrower than Claim 1 because it requires both:

The delafloxacin meglumine trihydrate; and
The crystalline structure corresponding to Figure 2.

A material can satisfy Claim 1 without satisfying Claim 3 if it is the trihydrate but is amorphous, disordered, or a different crystalline form. Conversely, PXRD matching is not sufficient if the material does not have the claimed chemical identity and trihydrate status.

Claim 4: Dehydration process

Claim 4 covers a process for making the delafloxacin meglumine salt by dehydrating the trihydrate.

The claim is process-specific. It is relevant to manufacturers that begin with the trihydrate and deliberately remove water to produce another salt form. It does not, on its face, cover every process for making anhydrous delafloxacin meglumine.

Potential infringement questions include:

Whether the starting material is the claimed trihydrate.
Whether the process actually performs a dehydration step.
Whether incidental drying qualifies as the claimed dehydration.
Whether the final product is the claimed delafloxacin meglumine salt.
Whether the process uses conditions materially different from those described in the specification.

Claim 5: Product-by-process delafloxacin meglumine

Claim 5 covers delafloxacin meglumine "prepared as described in claim 4."

This is a product-by-process claim. Under US patent law, the process language generally limits the claim for infringement purposes. A product made by a materially different process may present a stronger noninfringement position even if it is chemically indistinguishable from the product made by the claimed process. The Federal Circuit has treated product-by-process limitations as enforceable process limitations in product claims. [4]

The claim nevertheless creates litigation risk where the manufacturing route is not publicly visible. Process discovery, batch records, development reports, and analytical data would normally be central to enforcement.

Claim 6: Crystallization from water, with or without alcohol

Claim 6 covers making the trihydrate by crystallizing delafloxacin meglumine from water, with or without an alcohol.

This claim targets a practical isolation route. The phrase "with or without an alcohol" broadens the solvent system to include:

Water alone.
Water and ethanol.
Water and another alcohol permitted by the claim construction.
Aqueous crystallization in which alcohol is absent.

The claim does not appear to require a specific alcohol identity, concentration, temperature, seeding step, cooling profile, or agitation rate unless those limitations are incorporated elsewhere through the specification or prosecution history.

Claim 7: Product-by-process trihydrate

Claim 7 covers delafloxacin meglumine trihydrate prepared by the crystallization process in Claim 6.

Like Claim 5, Claim 7 combines a product limitation with a process limitation. Its value is highest when the claimed crystallization route is commercially preferred and competitors cannot readily establish the trihydrate through an alternative route.

How broad is the patent’s scope?

The patent has a layered claim structure.

Claim type	Claims	Relative scope	Main limitation
Chemical composition	1	Broadest within this patent	Must be delafloxacin meglumine trihydrate
Crystalline form	2	Intermediate	Must match Figure 1 PXRD profile
Crystalline trihydrate	3	Narrower	Must match Figure 2 PXRD profile and be trihydrate
Manufacturing process	4, 6	Route-specific	Dehydration or aqueous crystallization
Product-by-process	5, 7	Product and process dependent	Product must be made by the stated route

The patent is not a basic compound patent. It is a solid-state and process patent. Its commercial importance comes from controlling forms suitable for isolation, storage, formulation, and manufacturing rather than from claiming the quinolone antibacterial structure in all forms.

What does the patent not claim?

The claims do not expressly cover:

Delafloxacin free acid in every physical form.
Every delafloxacin salt.
Every meglumine salt regardless of hydration state.
Delafloxacin sodium, potassium, hydrochloride, or other salts.
Intravenous or oral dosage forms.
A tablet comprising delafloxacin meglumine.
A method of treating bacterial infection.
A dosing regimen.
A specific indication such as acute bacterial skin and skin-structure infections or community-acquired bacterial pneumonia.
A particular particle-size distribution.
A sterile injectable composition.
A particular excipient system.
A polymorph that does not match the referenced PXRD pattern.

Those subjects may be covered by separate patents, patent applications, regulatory exclusivity, or trade-secret protection.

What are the key infringement issues?

Identity and salt stoichiometry

An accused product must first be shown to contain the claimed delafloxacin-meglumine salt. Analytical proof would typically include assay, spectroscopy, elemental analysis, ion-pair or salt-stoichiometry testing, and water-content analysis.

Hydration state

Claim 1 requires the trihydrate. Water content can vary with relative humidity, temperature, drying history, and analytical method. A nominally trihydrate batch may lose or gain water during handling. Karl Fischer analysis, thermogravimetric analysis, and PXRD would likely be used together.

PXRD matching

Claims 2 and 3 depend on the Figure 1 or Figure 2 diffraction pattern. The relevant comparison is not necessarily visual identity of every peak. Peak positions, relative intensities, instrument conditions, sample preparation, and permissible analytical variation can affect the infringement analysis.

A different polymorph may avoid Claims 2 and 3 even if it has the same chemical composition.

Process evidence

Claims 4 and 6 require particular preparation routes. Those claims are difficult to evaluate from the finished drug product alone. Manufacturing records, batch instructions, solvent composition, drying conditions, and crystallization records would be important.

When does US 7,728,143 expire?

The patent issued on June 1, 2010. Its term is generally calculated from the applicable earliest nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers, and any patent-term extension.

Public patent records associate the patent with a December 2006 priority framework. On that basis, the ordinary 20-year term would be expected to reach approximately December 2026, before any patent-term adjustment. The exact enforceable expiration date must be taken from the USPTO patent-term data and the issued patent’s term calculations. [1]

The patent’s expiration should not be confused with Baxdela’s regulatory exclusivity. The FDA approved Baxdela in 2017, and delafloxacin received Qualified Infectious Disease Product treatment. FDA regulatory exclusivity and patent term operate under separate statutes and can end on different dates. [2][3]

What is the FDA and Orange Book status of Baxdela?

Baxdela is FDA-approved under NDA 208610 for designated bacterial infections, including acute bacterial skin and skin-structure infections and community-acquired bacterial pneumonia in adults, subject to the approved labeling.

The Orange Book is the relevant source for listed patents and any use codes associated with the approved NDA. A patent’s inclusion in the Orange Book does not establish that every claim covers every use of the drug. Conversely, the absence of a particular formulation or method-of-use claim from the supplied patent does not establish that no separate patent covers it. [2]

For delafloxacin, the regulatory analysis should separate:

The active ingredient and salt.
The approved oral tablet.
The intravenous formulation.
The approved indications.
Any listed crystalline-form or manufacturing patent.
QIDP and new chemical entity exclusivity.
Any pediatric or other statutory exclusivity.

Are there Paragraph IV challenges or generic settlements?

The supplied claim set does not establish a Paragraph IV filing, ANDA litigation, or settlement agreement. A definitive litigation position requires review of FDA Paragraph IV notifications, district-court complaints, docket entries, and any settlement filings.

For a generic delafloxacin applicant, a Paragraph IV strategy could target:

Noninfringement based on a different salt or hydrate.
Noninfringement based on a different polymorph.
Invalidity for anticipation or obviousness.
Lack of written description or enablement for PXRD-defined forms.
Process differences for Claims 4 and 6.
Product-by-process limitations in Claims 5 and 7.
Expiration or unenforceability of the patent.

The most direct challenge would likely focus on whether the proposed generic contains the claimed trihydrate or crystalline form. A process-only design-around is more credible for Claims 4 and 6 than for Claim 1, because Claim 1 is not process-limited.

How strong is the patent estate?

Composition strength

Claim 1 has relatively strong commercial reach within the specific trihydrate. It can cover the product independent of the manufacturing route. Its vulnerability would center on claim construction, prior art, enablement, and proof of trihydrate identity.

Solid-state strength

Claims 2 and 3 provide analytical coverage of defined crystalline forms. These claims can be effective when the commercial product consistently uses the claimed form. Their strength depends on reproducible PXRD evidence and clear differentiation from prior-art forms.

Process strength

Claims 4 and 6 have narrower scope. They may be avoided by changing the starting form, solvent system, dehydration mechanism, or crystallization route. Their value increases where the claimed process is the most economical or reliable route to the commercial form.

Product-by-process strength

Claims 5 and 7 may be harder to enforce than pure product claims because the process limitations must be satisfied. They can still create risk when the accused manufacturer uses the claimed route or when process evidence is discoverable.

Overall, US 7,728,143 is strongest against a product that uses delafloxacin meglumine trihydrate or the claimed crystalline forms and is manufactured through aqueous crystallization or dehydration. It is weaker against a non-meglumine salt, a distinct polymorph, or an independently developed process that produces a different solid form.

What generic launch scenarios exist?

Scenario	Likely exposure under US 7,728,143
Generic uses delafloxacin meglumine trihydrate matching Figure 2	High risk under Claims 1 and 3
Generic uses the Figure 1 crystalline form	Potential risk under Claim 2
Generic uses delafloxacin meglumine but a different polymorph	Lower risk under Claims 2 and 3; Claim 1 depends on hydration state
Generic uses delafloxacin free acid	Generally outside the express claims
Generic uses a non-meglumine salt	Generally outside the express claims
Generic makes the trihydrate by water crystallization	Potential risk under Claims 6 and 7
Generic makes the salt through a different route	Lower process-claim risk, but composition claims remain relevant
Generic uses a different dosage form but the same trihydrate API	Dosage form does not by itself avoid Claim 1

A first-filer or authorized-generic strategy would also depend on the FDA’s regulatory exclusivity, Orange Book listings, ANDA certification, and any litigation settlement.

What geographic coverage does the patent provide?

US 7,728,143 provides protection only in the United States. Parallel protection may exist in foreign jurisdictions through the related international and national-phase filings, but foreign claims, expiration dates, prosecution amendments, and validity positions can differ.

For commercial planning, the relevant jurisdictions include the United States, European Union member states, United Kingdom, Japan, Canada, Australia, and major emerging pharmaceutical markets. A US noninfringement position does not establish freedom to operate in those jurisdictions.

Does the patent create manufacturing or trade-secret barriers?

Yes. The patent covers selected solid-state transitions and crystallization operations. Even after patent expiration, the commercial process may remain protected by know-how involving:

Seeding and supersaturation control.
Water activity.
Solvent exchange.
Drying endpoint.
Particle engineering.
Polymorph conversion control.
Scale-up conditions.
Stability management.

Those process details may be protected as trade secrets rather than patents. Patent expiration therefore does not automatically eliminate all manufacturing barriers.

Key Takeaways

US 7,728,143 is a delafloxacin meglumine solid-state and process patent.
Claim 1 is the broadest claim and covers the trihydrate salt as a product.
Claims 2 and 3 are PXRD-defined crystalline-form claims.
Claims 4 and 6 cover dehydration and aqueous crystallization processes.
Claims 5 and 7 are product-by-process claims and are narrower than pure composition claims.
The patent does not expressly claim delafloxacin broadly, treatment methods, tablets, injections, or every delafloxacin salt.
The ordinary patent term appears to run to approximately December 2026, subject to USPTO term calculations.
Baxdela’s FDA exclusivity and any QIDP benefit are separate from the patent term.
A generic using the same trihydrate or claimed PXRD form faces the greatest risk.
A distinct salt, polymorph, or independently developed process may offer a design-around path.
Paragraph IV, Orange Book, litigation, and settlement conclusions require the applicable FDA and court records, not the claim text alone.

FAQs

Is US 7,728,143 a patent on delafloxacin itself?

No. It is directed primarily to delafloxacin meglumine solid forms and processes. It does not claim every chemical form of delafloxacin.

Can a generic avoid the patent by using delafloxacin free acid?

Potentially. The supplied claims recite the meglumine salt, so delafloxacin free acid is outside their literal chemical scope. Separate patents or regulatory requirements could still affect commercialization.

Does a PXRD mismatch automatically avoid infringement?

No. A mismatch may support noninfringement of a PXRD-defined claim, but the analysis depends on the complete claim language, analytical variation, claim construction, and whether another claim, such as Claim 1, covers the material.

Are delafloxacin tablets and injections separately protected by this patent?

The supplied claims do not recite a tablet, injection, excipient, container, or dosage regimen. Separate formulation or method-of-use patents would need to be analyzed independently.

Can the patent be designed around by changing the crystallization solvent?

Possibly for the process claims, but not necessarily for Claim 1. If the resulting product is still delafloxacin meglumine trihydrate, the composition claim may remain relevant even when the manufacturing route changes.

References

United States Patent and Trademark Office. (2010). United States Patent No. 7,728,143: Delafloxacin meglumine solid forms and processes.
U.S. Food and Drug Administration. (2017). Baxdela (delafloxacin meglumine) prescribing information and NDA 208610 approval materials.
U.S. Food and Drug Administration. (n.d.). Orange Book: Approved drug products with therapeutic equivalence evaluations.
United States Court of Appeals for the Federal Circuit. (2008). Abbott Laboratories v. Sandoz, Inc., 566 F.3d 1282.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Melinta	BAXDELA	delafloxacin meglumine	POWDER;INTRAVENOUS	208611-001	Jun 19, 2017		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial		Y			⤷ Start Trial
Melinta	BAXDELA	delafloxacin meglumine	TABLET;ORAL	208610-001	Jun 19, 2017		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial		Y			⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Canada	2582954	⤷ Start Trial
Cyprus	1125048	⤷ Start Trial
Denmark	3056492	⤷ Start Trial
European Patent Office	1802607	⤷ Start Trial
European Patent Office	3056492	⤷ Start Trial
European Patent Office	3957632	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 7,728,143