Details for Patent: 10,238,634

Which drugs does patent 10,238,634 protect, and when does it expire?

Patent 10,238,634 protects NUVESSA and is included in one NDA.

This patent has fifteen patent family members in eight countries.

Summary for Patent: 10,238,634

Title:	Aqueous-based metronidazole gel formulations
Abstract:	The present disclosure provides mucoadhesive aqueous-based gel formulations of metronidazole useful for a variety of purposes, including intravaginal application as a therapeutic approach towards the treatment of individuals suffering from and/or diagnosed with bacterial vaginosis.
Inventor(s):	Michael T. Nordsiek, Kodumudi S. Balaji
Assignee:	Chemo Research SL
Application Number:	US14/921,737
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 10,238,634
Patent Claim Types: see list of patent claims	Use; Composition;

United States Patent 10,238,634 (Metronidazole Intravaginal Aqueous Gel): Claim Scope, Protection Boundaries, and US Patent Landscape

US Patent 10,238,634 centers on a metronidazole intravaginal aqueous-based gel defined by a tightly bounded composition window (1.3–1.5% metronidazole; 1–3% mucoadhesive polymer; 30–60% water; 30–60% ternary solvent) plus measured performance targets (pH 3.0–5.0 and viscosity 200,000–400,000 mPa·s at 25°C). The dependent claims narrow to specific polymer classes, specific solvent subranges, and single-dose treatment regimens for bacterial vaginosis (BV).

From a freedom-to-operate and portfolio-defense perspective, the estate’s leverage is strongest against products that copy the same formulation architecture and rheology/pH rather than against generic metronidazole gels with different solvent systems or viscosity profiles.

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What patents protect metronidazole intravaginal aqueous gel compositions like US 10,238,634?

The protection in US 10,238,634 is fundamentally formulation-anchored with two hard performance gates:

1. Composition architecture

• Metronidazole: ~1.3–1.5% w/w
• Mucoadhesive gelling polymer(s): ~1–3% w/w
• Water: ~30–60% w/w
• Ternary solvent system: ~30–60% w/w, consisting of:
  • Lower aromatic alcohol(s): benzyl alcohol / 2-methylbenzyl alcohol / phenoxyethanol
  • Lower alkylene diol(s): ethylene glycol / propylene glycol
  • Polyoxyalkylene(s): polyethylene glycol (PEG) / polypropylene glycol (PPG) (and mixtures)

2. In-use-like physicochemical properties

• Aqueous phase pH: ~3.0–5.0
• Viscosity ~200,000–400,000 mPa·s at 25°C, measured with:
  • Controlled shear rate method
  • Bohlin CVO 100 rheometer
  • Rheometer settings referenced as “Table 11”

Core claim set that drives “what is protected”

• Claim 1: The broad independent composition claim with all window constraints and the measured viscosity/pH gates.
• Claim 2: Polymer selection constraint (HEC, carbomer, polycarbophil).
• Claim 8: A second independent composition claim with additional specificity:
  • Ternary solvent “consists of” rather than “comprises”
  • Explicit subranges for each solvent component class
• Claim 3 and Claim 4–5: Methods of treating BV using a single intravaginal administration with a metronidazole gel dose-regimen structure.

Key legal/claim construction levers embedded in the language

• “Comprising” vs “consists of”
  • Claim 1 uses “comprises” for the solvent system: defendants may argue room for extra components.
  • Claim 8 uses “consists of” for the ternary solvent system: it is more restrictive if the accused formulation adds other solvent components to that system.
• Functional/measurement constraints
  • Viscosity and pH are not merely formulation targets; they are claim limitations tied to specified measurement method and instrument. That increases enforceability where the accused product fails rheology/pH windows or uses a distinguishable measurement approach.
• Tight numeric ranges
  • 1.3–1.5% metronidazole is unusually narrow for BV topical compositions, which helps narrowing infringement to near-identical actives loading.

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What is the scope of claim 1 versus claim 8 in US 10,238,634?

Claim 1: “comprising” ternary solvent system + global windows

Scope definition (Claim 1):

• Metronidazole: 1.3–1.5%
• Mucoadhesive polymer: 1–3%
• Water: 30–60%
• Ternary solvent system: 30–60% with component classes allowed:
  • Lower aromatic alcohol(s)
  • Lower alkylene diol(s)
  • Polyoxyalkylene(s)
• Performance: pH 3.0–5.0
• Performance: viscosity 200k–400k mPa·s at 25°C per Bohlin CVO 100 controlled shear rate method and Table 11 settings

Practical infringement boundary:
To infringe, an accused product generally needs the full combination: the narrow metronidazole percentage, the polymer window, the ternary solvent share, and the specified pH/viscosity measurement outcome.

Claim 8: “consists of” ternary solvent system + explicit subranges

Scope definition (Claim 8):

• Metronidazole: 1.3–1.5%
• Polymer: 1–3% and limited to HEC or polycarbophil (carbomer excluded from this independent claim)
• Water: 30–60%
• Ternary solvent system: 30–60%, and its composition is restricted because it “consists of”:
  • Aromatic alcohol(s): 1.3–2.5%
  • Alkylene diol(s): 3–20%
  • Polyoxyalkylene(s): 10–50%
• Performance: pH 3.0–5.0
• Performance: viscosity 200k–400k mPa·s at 25°C via the same specified method/instrument

Practical infringement boundary:
Claim 8 is narrower than Claim 1 on polymer class and solvent architecture. It is easier to spot copying because the solvent component subranges are explicitly spelled out.

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Which mucoadhesive gelling polymers are covered by US 10,238,634?

Claim 2 and Claim 5: Polymer class narrowing

• Claim 2 / Claim 5 restrict polymers to:
  • hydroxyethylcellulose (HEC)
  • carbomer
  • polycarbophil
  • and mixtures

Claim 8 independent composition: polymer subset

• Claim 8 limits to:
  • hydroxyethylcellulose
  • polycarbophil
  • mixtures
• This matters because a formulation using carbomer may be outside Claim 8 but can still be within Claim 1 + Claim 2 or within method claims that incorporate the relevant dependent claim limits.

Portfolio implication

Even where generic or follow-on products use metronidazole at similar strength, polymer selection (and the resulting rheology) becomes a key infringement determinant.

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What solvents and solvent subranges are protected (benzyl alcohol, propylene glycol, PEG/PPG)?

Solvent classes in Claim 1 (component classes)

• Lower aromatic alcohols: benzyl alcohol, 2-methylbenzyl alcohol, phenoxyethanol
• Lower alkylene diols: ethylene glycol, propylene glycol
• Polyoxyalkylenes: PEG (polyoxyethylene), polypropylene glycol (PPG, polyoxypropylene)

Claim 1 allows “one or more” within each class and uses “comprises” for the ternary solvent system, allowing possible co-ingredients outside that ternary solvent system (subject to the rest of the claim limitations).

Solvent subranges in Claim 8 (explicit “consists of” sub-structure)

• Aromatic alcohol: 1.3–2.5% w/w
• Alkylene diol: 3–20% w/w
• Polyoxyalkylene: 10–50% w/w
• Ternary solvent system total: 30–60%

Claim 9: Example-specific restriction

Claim 9 ties to a more specific “ternary solvent system consists of” configuration:

• Aromatic alcohol: benzyl alcohol 1.3–2.5%
• Alkylene diol: propylene glycol 3–20%
• Polyoxyalkylene: PEG 10–50%

Portfolio implication:
A product using a different aromatic alcohol (e.g., phenoxyethanol) can fall into Claim 1 but may avoid Claim 9. A product using non-listed solvent components inside the “ternary solvent system” can avoid Claim 8 due to “consists of.”

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When does exclusivity or patent protection end for intravaginal metronidazole gel under US 10,238,634?

No filing date, grant date, family members, or terminal disclaimer terms were provided. Without those, the exact statutory expiration and any pediatric extension or PTA impact cannot be derived from the claim text alone.

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What BV treatment methods are claimed (single-dose regimens) and how narrow are they?

Claim 3: “single administration” (broad method structure)

• Treat BV by intravaginally applying a single administration of the gel of Claim 1.

Claim 4: Single-dose, once daily for 1–3 days (more specific)

Claim 4 requires:

• A single dose aqueous-based metronidazole gel composition that includes:
  • 60–70 mg metronidazole
  • Metronidazole concentration still 1.3–1.5%
  • Water: 30–60%
  • Polymer: 1–3%
  • Ternary solvent: 30–60%, with the same component classes as Claim 1
  • pH 3.0–5.0
  • Viscosity: 200k–400k mPa·s at 25°C per Bohlin CVO 100 + Table 11 method/settings
• Administration: once a day for one, two, or three days.

Claim 5: Polymer-limited method

Claim 5 limits the method’s polymers to HEC, carbomer, and polycarbophil.

Practical method infringement boundary

A competitor can potentially design around by changing:

• dose amount (mg),
• dosing schedule (e.g., twice daily),
• or the gel composition meeting the claim’s strict pH/viscosity and solvent/polymer architecture.

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What patent landscape risks exist for generic or “AB-rated” intravaginal metronidazole gels?

Based only on the claim structure, infringement risk concentrates on products that match all of the following simultaneously:

1. metronidazole loading near 1.3–1.5% w/w
2. mucoadhesive polymer at 1–3%
3. a ternary solvent at 30–60% using the specified component classes
4. a pH in 3.0–5.0
5. viscosity 200k–400k mPa·s at 25°C by the specified measurement approach

If a generic product changes any one of these axes (for example, uses a different polymer (silicone-based, different carbomer grade with different rheology, HPMC instead of HEC), uses a different humectant system that changes pH, or targets a viscosity outside the claimed band), it can potentially step out of the claim set even if metronidazole strength remains comparable.

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How strong is the patent estate for US 10,238,634 based on claim enforceability features?

Strength factors present in the provided claims:

• Tightly bounded numeric windows (especially metronidazole 1.3–1.5% and viscosity band).
• Measured property limits tied to instrument and method language. This can improve enforceability but also increases the technical burden for both plaintiff and defendant.
• Architectural constraints on the solvent system (ternary solvent definition, plus “consists of” in Claim 8 and Claim 9).
• Method-of-use integration with dosing schedule and dose amount (Claim 4).

Weakening factors that often appear in comparable formulations (assessment depends on full spec/prosecution history, not provided here):

• Broad use of “one or more” and “mixtures thereof,” which can create multiple paths for accused formulations to still fall within the genus.
• Measurement limitations can create factual battles about test conditions, lot variability, and rheometer settings.

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Which comparable formulations are most likely to fall inside the claims? (formulation design map)

Most likely in-scope designs share the following signature:

• 1.3–1.5% metronidazole in an intravaginal aqueous gel
• A mucoadhesive gelling polymer selected from the claimed set (HEC, carbomer, polycarbophil)
• A solvent system dominated by:
  • benzyl alcohol and/or phenoxyethanol (aromatic alcohol class),
  • propylene glycol and/or ethylene glycol (alkylene diol class),
  • PEG and/or PPG (polyoxyalkylene class),
• A pH that stays acidic at 3.0–5.0
• High gel viscosity 200k–400k mPa·s at 25°C

Most likely out-of-scope designs:

• Use metronidazole concentrations outside 1.3–1.5%.
• Use different solvent systems that reduce/alter the ternary solvent fraction or introduce additional solvent components within the “ternary solvent system” to avoid “consists of.”
• Target viscosity outside 200k–400k mPa·s or fail pH band.
• Use different polymer families or exclude the claimed polymer selections (for Claim 8 specifically).

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Key Takeaways

• US 10,238,634 protects a metronidazole intravaginal aqueous gel defined by a specific composition window and measured performance limits (pH 3.0–5.0; viscosity 200,000–400,000 mPa·s at 25°C).
• Claim breadth is split: Claim 1 is a broader composition claim (ternary solvent “comprises”), while Claim 8/9 narrow solvent and polymer configurations via “consists of” and explicit subranges.
• The highest infringement concentration is against products that reproduce the 1.3–1.5% metronidazole level and hit the same rheology and pH using the claimed ternary solvent architecture.
• Method claims add regimen constraints, particularly single-dose intravaginal treatment and once-daily dosing for 1–3 days with 60–70 mg metronidazole.

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FAQs

1) What product properties are most decisive for infringement of US 10,238,634?
pH 3.0–5.0 and viscosity 200,000–400,000 mPa·s at 25°C (plus meeting the metronidazole, polymer, and ternary solvent concentration windows).

2) Can a product avoid Claim 8 by changing the polymer type?
Claim 8 limits polymer to hydroxyethylcellulose and/or polycarbophil; using carbomer can potentially avoid Claim 8 while still possibly implicating Claim 1/2.

3) How does “consists of” in Claim 8 and Claim 9 affect design-around strategy?
It restricts the ternary solvent system to the listed solvent components and subranges, making additions to that ternary system a potential avoidance path.

4) Does Claim 4 protect a dosing schedule even if the gel composition matches Claim 1?
Yes. Claim 4 requires both a specific gel dose structure (including 60–70 mg metronidazole and the same performance/composition limitations) and a once-daily regimen for 1–3 days.

5) Are formulations with similar metronidazole strength but different viscosity automatically safe?
Not automatically, but stepping outside the 200k–400k mPa·s viscosity band and/or the pH 3.0–5.0 window is a direct route to avoid key claim limitations.

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References

No external sources were provided or cited in the prompt, and none can be produced from the claim text alone.

Drugs Protected by US Patent 10,238,634

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Alembic Therap	NUVESSA	metronidazole	GEL;VAGINAL	205223-001	Mar 24, 2014		RX	Yes	Yes			Y

International Family Members for US Patent 10,238,634

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2012275292
Australia	2016200825
Brazil	112013033759