US Patent 8,252,813: Delafloxacin Meglumine Crystal-Form Claims, Scope, Expiration, and Patent Landscape

US Patent 8,252,813 protects specific crystalline forms of delafloxacin meglumine, including an anhydrous or non-hydrated meglumine salt and a trihydrate form. Its claims cover the active pharmaceutical ingredient in crystalline form, pharmaceutical compositions containing the salt, oral and parenteral dosage forms, defined excipient combinations, and methods of treating bacterial infections in mammals and fish.

The patent is commercially relevant to Baxdela, the branded delafloxacin product. The strongest infringement positions are claims 37 and 38, which claim the crystalline salts directly, and claims 6, 7, 21, and 22, which define the forms through powder X-ray diffraction and crystallographic parameters. Based on the patent family’s priority structure, the ordinary 20-year term runs into December 2029, subject to the applicable patent-term adjustment and any regulatory patent-term extension.

What drug and salt does US Patent 8,252,813 cover?

The lengthy chemical name in the claims identifies delafloxacin, specifically its meglumine salt.

Patent claim terminology	Commercial or chemical identification
D-Glucitol, 1-deoxy-1-(methylamino)-	Meglumine
Quinolone carboxylate component	Delafloxacin
Meglumine salt	Delafloxacin meglumine
Trihydrate salt	Delafloxacin meglumine trihydrate
Brand product	Baxdela
FDA sponsor at approval	Melinta Therapeutics, Inc.
Therapeutic category	Fluoroquinolone antibacterial

Delafloxacin is a fluoroquinolone antibacterial approved in the United States for specified acute bacterial skin and skin-structure infections and community-acquired bacterial pneumonia. The commercial product has been supplied in oral and intravenous dosage forms.

The patent does not claim every delafloxacin formulation generically. It focuses on compositions and crystalline forms containing delafloxacin meglumine, including a separately claimed trihydrate form.

What are the independent claims in US Patent 8,252,813?

The patent contains four principal independent-claim groups.

Claim	Subject matter	Practical scope
1	Therapeutic composition containing delafloxacin meglumine and an excipient	Broad composition claim
16	Therapeutic composition containing delafloxacin meglumine trihydrate and an excipient	Broad trihydrate composition claim
31	Treatment of bacterial infection in a fish or mammal using delafloxacin meglumine	Method-of-use claim
34	Treatment of bacterial infection in a fish or mammal using delafloxacin meglumine trihydrate	Method-of-use claim
37	Crystalline delafloxacin meglumine defined by lattice parameters	Direct compound or crystal-form claim
38	Crystalline delafloxacin meglumine trihydrate defined by lattice parameters	Direct trihydrate crystal-form claim

Claims 14 and 29 are narrower independent-style composition limitations directed to an oral solid dosage form containing the salt, povidone, cellulose, and magnesium stearate. They require the recited excipient combination and therefore have narrower literal scope than claims 1 and 16.

How do the claims divide between delafloxacin meglumine and its trihydrate?

The patent establishes two principal protected solid forms.

Delafloxacin meglumine form

Claims 1 through 15 address a delafloxacin meglumine composition. The claims cover:

A therapeutic composition containing the salt and an excipient.
Therapeutically acceptable quantities.
Crystalline material.
At least about 95% crystalline purity.
Chemical purity levels of approximately 97%, 98%, or 100%.
Oral and parenteral dosage forms.
A solid oral dosage form containing povidone, cellulose, and magnesium stearate.
A crystalline form identified by the powder diffraction pattern in Figure 1.
A monoclinic crystal system with specified lattice parameters.

Delafloxacin meglumine trihydrate

Claims 16 through 30 address the trihydrate. They substantially replicate the first claim group but substitute the trihydrate salt and the Figure 2 diffraction pattern.

The trihydrate claims cover:

A therapeutic composition with delafloxacin meglumine trihydrate and an excipient.
Crystalline purity of at least about 95%.
Chemical purity of approximately 97%, 98%, or 100%.
Oral and parenteral dosage forms.
The same specified solid oral excipient combination.
A distinct powder diffraction pattern in Figure 2.
A distinct monoclinic crystal structure and lattice parameters.

This separation matters because a manufacturer can avoid literal infringement of the trihydrate claims by using a different solid form, but it may still face claims directed to the non-trihydrate meglumine form or other delafloxacin patents.

What crystalline forms are claimed by US 8,252,813?

The patent uses both analytical and structural definitions.

Form	Lattice parameters	Crystal system and space group	Radiation and temperature
Delafloxacin meglumine	a about 16.4460 Å; b about 21.4010 Å; c about 5.3050 Å; β about 109°	Monoclinic; P21/c or P21/m	Mo-Kα radiation at about 25°C
Delafloxacin meglumine trihydrate	a about 8.2490 Å; b about 29.9840 Å; c about 12.5070 Å; β about 105°	Monoclinic; P21/c or P21/m	Mo-Kα radiation at about 25°C

Claims 6 and 21 refer to the powder X-ray diffraction patterns shown in Figures 1 and 2. Claims 7 and 22 refer to the lattice parameters and crystal system. Claims 37 and 38 claim the crystalline materials directly using the lattice-parameter definitions.

The term “about” creates a claim-construction issue. Infringement would ordinarily depend on the accepted analytical tolerance, measurement conditions, instrument calibration, sample preparation, and whether the accused material has the same claimed crystal form despite small numerical deviations.

How broad are the composition claims?

Claims 1 and 16 are broader than the crystal-characterization claims because they require the presence of the specified salt and an excipient but do not expressly require crystallinity.

A composition potentially falls within claim 1 if it contains:

Delafloxacin meglumine.
At least one excipient.
A therapeutic composition context.

A composition potentially falls within claim 16 if it contains:

Delafloxacin meglumine trihydrate.
At least one excipient.
A therapeutic composition context.

The composition claims do not require a particular dosage strength. Claim 2 and claim 17 add the “therapeutically acceptable amount” limitation, which is unlikely to create a meaningful commercial distinction for an approved medicinal product.

Claims 8 through 11 and 23 through 26 add chemical-purity limitations. These claims are narrower and may be easier to design around if a competing product uses a different salt, a different hydrate state, or a material outside the specified purity range. Their practical value is greater against commercial pharmaceutical material, which normally has high chemical purity.

What formulations are protected by US Patent 8,252,813?

The patent protects both broad dosage-form categories and a specified oral tablet formulation.

Claim group	Dosage form or formulation
Claims 12 and 27	Oral administration
Claims 13 and 28	Parenteral administration
Claims 14 and 29	Solid oral dosage form
Claims 14 and 29	Delafloxacin meglumine or trihydrate, povidone, cellulose, magnesium stearate
Claims 15 and 30	Therapeutically acceptable amount

The excipient claims appear directed to a conventional solid oral dosage form. “Cellulose” is broad on its face and may encompass microcrystalline cellulose depending on claim construction and specification support. “Providone” in the supplied claim text appears to be a typographical variant of povidone, the commonly used pharmaceutical binder.

The patent does not require a particular tablet coating, dissolution profile, dose strength, release mechanism, or packaging configuration in the quoted claims. A product using the same salt and excipient combination may face literal or equivalent-infringement risk even if it uses a different tablet shape or coating.

What method-of-use patents and treatment claims are included?

Claims 31 through 36 cover treating bacterial infection in a fish or mammal. The dependent claims narrow the subject to mammals and specify a dose range of approximately 0.03 to 200 mg/kg body weight.

The method claims are commercially more important for use-based enforcement than for ordinary product sales. A generic manufacturer can reduce risk by pursuing a labeling strategy that omits patented indications, but that approach does not necessarily avoid infringement if the product’s composition independently falls within claims 1, 16, 37, or 38.

The claims cover:

Bacterial infection treatment.
Fish and mammalian subjects.
Oral or parenteral administration through the claimed composition.
A broad dose range.
Both delafloxacin meglumine and the trihydrate.

Because the method claims are not limited to a named pathogen in the quoted claims, they are facially broad. Their enforceability would depend on written-description support, enablement, claim construction, prosecution history, and the factual circumstances of the accused use.

When does US Patent 8,252,813 expire?

The patent’s ordinary patent term is tied to the earliest effective nonprovisional or international filing date in its family. Public patent-family records associate the crystal-form application with a December 2009 priority framework, placing the unadjusted term in December 2029.

Event	Date or period
Patent issued	August 28, 2012
Expected ordinary term endpoint	December 2029
FDA approval of Baxdela	June 19, 2017
NME statutory exclusivity	Generally ended June 19, 2021
Paragraph IV risk window	Begins when an ANDA applicant challenges a listed patent
Regulatory extension	Must be checked against the approved-product patent listing and FDA patent-term records

The relevant commercial date is the Orange Book expiration date, not the issue date. Patent-term adjustment can move the endpoint beyond the basic 20-year calculation. A patent-term extension under 35 U.S.C. § 156 is a separate question and cannot be assumed solely from FDA approval.

What is the Orange Book status of US 8,252,813?

US Patent 8,252,813 has been associated with the Baxdela delafloxacin product patent estate and is relevant to generic-entry analysis. Orange Book treatment depends on the specific NDA, dosage form, patent listing, and current FDA publication.

The patent’s claim subject matter is suitable for Orange Book listing because it covers:

The active ingredient in a specified salt form.
Pharmaceutical compositions.
Dosage forms.
Methods of treating bacterial infections.

For ANDA litigation, a Paragraph IV certification would typically assert that the listed patent is invalid, unenforceable, or not infringed. A Paragraph III certification would defer approval until patent expiry. If the patent is listed for the relevant Baxdela product, a properly filed Paragraph IV notice could trigger a 45-day period for the NDA holder or patent owner to sue under the Hatch-Waxman statute.

FDA approval timing also matters. A first substantially complete ANDA with a qualifying Paragraph IV challenge may seek 180-day generic exclusivity, subject to forfeiture and other statutory conditions under 21 U.S.C. § 355(j).

Which companies are challenging the delafloxacin patent estate?

The relevant generic challengers would be ANDA applicants seeking approval for delafloxacin tablets or injection. Publicly available patent-risk reports often identify ANDA applicants through FDA litigation records rather than through the patent itself.

The central litigation questions are likely to be:

Whether the proposed product contains delafloxacin meglumine or the claimed trihydrate.
Whether the proposed solid form has the Figure 1 or Figure 2 PXRD pattern.
Whether the proposed product meets the lattice-parameter limitations.
Whether the formulation contains povidone, cellulose, and magnesium stearate.
Whether the proposed label induces use within the treatment claims.
Whether the patent remains enforceable after prosecution-history and terminal-disclaimer review.

No generic challenger is identified in the claim text supplied. A complete current challenger table requires docket-specific review of FDA Orange Book records, Paragraph IV notices, and federal court filings.

What patent litigation affects US 8,252,813?

The principal litigation pathway is Hatch-Waxman litigation following an ANDA Paragraph IV certification. The patent can be asserted through several independent theories:

Theory	Relevant claims
Salt-containing composition	Claims 1 and 16
Crystalline form	Claims 3-7 and 18-22
Purity-defined material	Claims 4-5, 8-11, 19-20, 23-26
Oral formulation	Claims 12, 14, 27, and 29
Parenteral composition	Claims 13 and 28
Treatment method	Claims 31-36
Direct crystal-form infringement	Claims 37 and 38

Claims 37 and 38 may be particularly important because they do not require an excipient or finished dosage form. A generic API supplier or finished-dose manufacturer could face a direct crystal-form claim if it makes, imports, sells, or uses the claimed form.

Settlement agreements, licenses, authorized-generic arrangements, and launch dates must be evaluated from the actual court docket and FTC settlement-disclosure materials. The patent document itself does not establish whether any settlement exists.

How strong is the patent estate for delafloxacin?

US 8,252,813 is a technically focused patent with meaningful commercial value because it claims defined solid forms rather than only a broad therapeutic use.

Strengths

Claims 37 and 38 directly target the crystalline materials.
The forms are defined by PXRD and crystallographic parameters.
The claims cover both drug substance and finished pharmaceutical compositions.
The trihydrate is separately claimed.
The oral formulation claims include common excipients used in tablets.
The method claims extend to mammals and fish.

Weaknesses and attack points

Crystal-form claims can be challenged on anticipation or obviousness based on prior solid-form disclosures.
Numerical lattice parameters using “about” can create construction and proof disputes.
Space-group language using “P21/c or P21/m” may raise indefiniteness or scope questions if the specification does not clearly explain the alternatives.
Composition claims requiring an excipient may be vulnerable to design-around using a different salt or dosage-form architecture.
Purity limitations may be difficult to enforce consistently if the analytical method is not fixed.
Treatment claims can face written-description, enablement, inducement, and label-scope defenses.
The patent’s expiration is earlier than later-filed formulation, process, or polymorph patents in the broader delafloxacin estate.

The patent is strongest against a product intentionally using the same delafloxacin meglumine crystal form or trihydrate. It is weaker against a product using a genuinely different salt, amorphous material, polymorph, solvate, or manufacturing route that does not produce the claimed form.

How can a generic manufacturer design around US 8,252,813?

Potential design-around strategies include:

Use delafloxacin in a different salt form.
Use a non-crystalline or amorphous form, if stable and pharmaceutically acceptable.
Use a polymorph with a different PXRD pattern and different lattice parameters.
Avoid the claimed trihydrate by controlling water activity and solid-state processing.
Use a different excipient system than povidone, cellulose, and magnesium stearate.
Pursue a label that omits methods covered by the treatment claims, subject to induced-infringement risk.
Develop a formulation under a later patent family that does not practice the claimed solid form.

Solid-state characterization is critical. A product can be chemically identical to delafloxacin meglumine but fall outside the patent if its crystal structure differs. Conversely, a product marketed under a different formulation name can still infringe if the underlying active ingredient is the claimed crystal form.

What manufacturing and intellectual-property barriers matter?

The principal manufacturing barrier is control of the solid state. Crystal form can depend on:

Solvent selection.
Water content.
Temperature profile.
Seeding.
Agitation.
Drying conditions.
Milling.
Storage humidity.
Conversion between anhydrous and hydrated forms.

A manufacturer must characterize both the drug substance and the final dosage form. Hydration or dehydration during processing can create a claim issue even if the intended starting material was different.

Analytical evidence would typically include:

Powder X-ray diffraction.
Single-crystal X-ray diffraction or crystallographic analysis.
Thermogravimetric analysis.
Differential scanning calorimetry.
Karl Fischer water determination.
Infrared or Raman spectroscopy.
Chemical assay and impurity profiling.

The most important technical question is whether the accused material matches the patented form under the claimed measurement conditions. A different manufacturing route does not avoid infringement if it produces the same claimed crystal.

How does US 8,252,813 compare with other delafloxacin patents?

The delafloxacin estate can be divided into several patent categories.

Patent category	Primary protection	Typical generic risk
Core compound patents	Delafloxacin molecule and related quinolones	Broadest chemical scope; often earliest expiry
Salt patents	Meglumine and other pharmaceutically acceptable salts	Risk for salt-specific products
Crystal-form patents	Anhydrous, hydrate, polymorph, or solvate forms	High risk where the generic copies the solid form
Formulation patents	Tablet, injectable, excipient, coating, or stability systems	Product-specific risk
Method-of-use patents	Bacterial indications, dosing, or patient populations	Label and induced-use risk
Process patents	Synthesis, crystallization, purification, and isolation	Manufacturing-route risk

US 8,252,813 is primarily a salt and solid-state patent. It does not replace core compound patents or later formulation patents. A generic launch requires clearance of the entire live estate, not this patent alone.

What is the biosimilar risk for Baxdela?

Biosimilar risk is not material because delafloxacin is a chemically synthesized small-molecule drug. Generic applicants use the ANDA pathway rather than the abbreviated pathway for biosimilar biological products.

The relevant competitive threats are:

Generic delafloxacin tablets.
Generic intravenous delafloxacin.
Alternative fluoroquinolone antibiotics.
Branded and generic agents used for skin infections or community-acquired pneumonia.
Hospital formulary substitution.

A generic applicant must address the listed patents and applicable regulatory exclusivities but does not need to establish biosimilarity under the Biologics Price Competition and Innovation Act.

What is the revenue exposure from US 8,252,813?

The patent protects a product used in hospital and outpatient antibacterial markets. Revenue exposure depends on:

Baxdela tablet and intravenous sales.
The share of sales using the claimed meglumine or trihydrate form.
The number and timing of ANDA filings.
The availability of alternative fluoroquinolones.
Hospital formulary placement.
Generic launch dates after patent litigation or settlement.
Whether later patents extend protection beyond US 8,252,813.

The commercial impact of an invalidity or noninfringement ruling could be greater than the direct value of this single patent because a successful generic solid form could remove a practical barrier to both oral and injectable competition.

Key Takeaways

US 8,252,813 covers delafloxacin meglumine and delafloxacin meglumine trihydrate.
The patent claims compositions, oral tablets, parenteral dosage forms, treatment methods, and crystalline drug substances.
Claims 37 and 38 are the most direct crystal-form claims.
Claims 7 and 22 use defined monoclinic lattice parameters to distinguish the protected forms.
The patent is most difficult to design around when a generic uses the same meglumine crystal or trihydrate.
A different salt, polymorph, hydrate state, or excipient system may reduce literal-infringement risk.
The ordinary patent term extends into December 2029 under the family’s priority framework, subject to patent-term adjustment and any applicable extension.
Delafloxacin is a small molecule, so biosimilar risk is not applicable.
Generic entry requires review of the complete delafloxacin patent estate, Orange Book listings, ANDA certifications, and any litigation or settlement agreements.

Frequently Asked Questions

Is US 8,252,813 a patent on delafloxacin itself?

No. The patent primarily protects delafloxacin meglumine salt forms, especially specified crystalline and trihydrate forms, together with compositions and therapeutic uses.

Can a generic use delafloxacin without infringing US 8,252,813?

Potentially, but only if it avoids all applicable claims. A different salt, polymorph, hydrate state, formulation, or manufacturing product may avoid some claims while remaining subject to other delafloxacin patents.

Does the patent cover both Baxdela tablets and intravenous products?

The claims expressly cover oral and parenteral dosage forms. Whether a specific Baxdela presentation practices the claims depends on its salt form, solid state, excipients, and manufacturing characteristics.

Are crystalline purity claims common barriers to generic approval?

They can be. Purity claims are narrower than broad composition claims, but commercial pharmaceutical material often meets high purity levels. The analytical method and meaning of “substantial” can become contested issues.

Is an ANDA applicant required to challenge US 8,252,813?

Not necessarily. An applicant may file a Paragraph III certification, Paragraph IV certification, or another certification permitted by the Hatch-Waxman framework, depending on the patent listing and proposed product. The strategic choice affects approval timing and litigation exposure.

References

U.S. Patent and Trademark Office. (2012). U.S. Patent No. 8,252,813, crystalline forms and compositions of delafloxacin meglumine.
U.S. Food and Drug Administration. (2017). Baxdela (delafloxacin meglumine) prescribing information. Melinta Therapeutics, Inc.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. Orange Book.
U.S. Code, 21 U.S.C. § 355. Abbreviated applications and patent certifications.
U.S. Code, 35 U.S.C. §§ 154, 156, and 271. Patent term, patent-term extension, and infringement.

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			TREATMENT OF ACUTE BACTERIAL SKIN AND SKIN STRUCTURE INFECTIONS CAUSED BY DESIGNATED SUSCEPTIBLE BACTERIA IN ADULTS	⤷ Start Trial
Melinta	BAXDELA	delafloxacin meglumine	TABLET;ORAL	208610-001	Jun 19, 2017		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial	Y			TREATMENT OF ACUTE BACTERIAL SKIN AND SKIN STRUCTURE INFECTIONS CAUSED BY DESIGNATED SUSCEPTIBLE BACTERIA IN ADULTS	⤷ 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

Details for Patent: 8,252,813

Which drugs does patent 8,252,813 protect, and when does it expire?

Summary for Patent: 8,252,813