Details for Patent: 8,399,445

Summary for Patent: 8,399,445

Title:	Acetylcysteine composition and uses thereof
Abstract:	This invention relates to novel acetylcysteine compositions in solution, comprising acetylcysteine and which are substantially free of metal chelating agents, such as EDTA. Further, this invention relates to methods of making and using the acetylcysteine compositions. The present compositions and methods are designed to improve patient tolerance and compliance, while at the same time maintaining the stability of the pharmaceutical formulation. The compositions and methods of this invention are useful in the treatment of acetaminophen overdose, acute liver failure, various cancers, methacrylonitrile poisoning, reperfusion injury during cardio bypass surgery, and radiocontrast-induced nephropathy, and can also be used as a mucolytic agent.
Inventor(s):	Leo Pavliv
Assignee:	Cumberland Pharmaceuticals Inc
Application Number:	US13/406,175
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,399,445
Patent Claim Types: see list of patent claims	Use; Composition; Formulation;

United States Patent 8,399,445 Scope, Claim Map, and US Patent Landscape for Intravenous Acetylcysteine in Acetaminophen Overdose

US Patent 8,399,445 is directed to methods of treating acetaminophen (paracetamol) overdose using a specific stable intravenous acetylcysteine aqueous composition. The claims are tightly centered on (i) acetylcysteine concentration, (ii) free-of-chelating-agent formulation constraints, (iii) intravenous-injectable pH window (6 to 7.5), (iv) airtight container with inert-gas headspace, and (v) dilution and administration schedule in 3-dose regimen terms (150 mg/kg, 50 mg/kg, 100 mg/kg; total 300 mg/kg). The landscape analysis below focuses on US claim scope boundaries, likely invalidity/obviousness pressure points, and where competitive products or generic entrants face formulation and container/process IP barriers.

Claim-constrained “core” elements (claims 1 and 6)

Both independent method claims follow the same structural pattern, with the main differences being the acetylcysteine concentration range and downstream dependent claim particulars:

• Disease/indication: “method of treating acetaminophen overdose”
• Drug substance/formulation: stable aqueous IV composition comprising
  • Acetylcysteine concentration
    • Claim 1: 200 mg/mL (single-point concentration)
    • Claim 6: 200 mg/mL to 250 mg/mL (range)
  • Free of chelating agents (composition constraint)
  • IV suitable form
  • pH from 6 to 7.5 (broad upper bound; lower bound is 6)
• Primary container constraint: composition sealed in an airtight container with
  • fill volume and
  • headspace occupied by a pharmaceutically inert gas
• Administration mechanics:
  • diluting the composition in an aqueous solution and
  • administering diluted composition to patient
• Dependent regimen anchor (claims 3-4, 8-9):
  • loading 150 mg/kg, then 50 mg/kg, then 100 mg/kg
  • total dose 300 mg/kg
• Dependent aqueous diluent specification (claims 2, 7, 12):
  • at least one of 5% dextrose, 0.45% sodium chloride, water for injection
• Preferred pH subrange (claims 5, 11):
  • 6.0 to <7.0

Additional independent claim type: liver damage method (claims 10-16)

Claim 10 expands the treated consequence:

• “method of treating acetaminophen overdose-induced liver damage”
• same IV composition and dilution/container/pH/chelator-free constraints
• dependent claims narrow to pH 6.0 to <7.0, include diluent options, include the same 150/50/100 mg/kg regimen, and specify liver failure including acute liver failure (claims 15-16)

What is the scope of US Patent 8,399,445 claims and what facts must be met for infringement?

Direct infringement “minimum tripwires”

To fall within the literal scope of independent claims 1 or 6, an accused activity must satisfy all of the following simultaneously:

1. The patient is treated for acetaminophen overdose (or overdose-induced liver damage for claim 10).
2. The provider uses a stable aqueous IV acetylcysteine composition that meets:
   • concentration (exact 200 mg/mL for claim 1; 200-250 mg/mL for claim 6)
   • chelator-free (no chelating agents)
   • pH 6 to 7.5
   • in a form suitable for IV injection
3. The composition is sealed in an airtight container with an inert gas headspace.
4. The composition is diluted in an aqueous solution, and the diluted composition is administered.
5. The clinical administration uses the claimed dilution and dosing regimen only if the accused claim is asserted through dependent claim coverage (claims 3-4, 8-9; and claim 2/5/6-7/11-14 depending on asserted counts).

Practical read-through: claim coverage depends on product packaging and composition release properties

Even if a generic or competitor has correct pH and acetylcysteine concentration and is chelator-free, litigation exposure can pivot on container fill/headspace and inert gas. Many formulations can match pH and concentration, but airtight inert-gas headspace requirements are commonly where product designs diverge.

Dosage schedule dependence

Independent claims (1, 6, 10) as provided in the user content do not expressly include the 150/50/100 regimen as part of the independent claim body. The regimen is in dependent claims (3-4, 8-9, 13-14). If asserted only against independent claims, the schedule element may not be required for literal infringement. In practice, patent owners often plead both independent and dependent theories.

How do claims 1 and 6 differ: concentration boundary and risk to generic or reformulation products?

• Claim 1: locks to 200 mg/mL acetylcysteine.
• Claim 6: covers 200-250 mg/mL.

Implication for competitors:

• A product formulated at <200 mg/mL or >250 mg/mL is positioned outside these independent concentration constraints (subject to doctrine-based arguments and potential alternative claims in the estate).
• A competitor at exactly 200 mg/mL must still satisfy pH 6-7.5, chelator-free, dilution, and inert-gas airtight container constraints.

What does “free of chelating agents” mean in enforceability terms?

The claim language makes chelators a binary composition feature. For infringement analysis, a factual inquiry typically becomes:

• whether any chelator additive exists (commonly sulfite stability, complexing stabilizers, or metal-binding excipients),
• whether a product uses excipients that could be characterized as chelating agents (depending on the formulation),
• whether the final injectable or diluted form contains such compounds.

Because the claims attach to the “stable aqueous pharmaceutical composition comprising … and … free of chelating agents,” the relevant composition is the one used for IV injection after preparation for use (and prior to dilution, to the extent dilution is separate in the claim).

What is the pH claim scope and how does it affect product design?

• Independent claims: pH 6 to 7.5
• Dependent preferred: 6.0 to less than 7.0

Exposure map:

• If an accused product has pH between 6.0 and 7.0, it risks coverage under the narrower dependent claims.
• If pH is between 7.0 and 7.5, it remains within the independent claims as described, but avoids the dependent subrange claims (5, 11).
• If pH is outside 6-7.5, it is outside the independent scope.

What does the airtight container with inert-gas headspace claim cover: drug product packaging claims or method-of-treatment?

Although the patent is framed as a method of treating, the claims incorporate a product packaging limitation:

• “composition is sealed in an airtight container comprising a fill volume … and a headspace volume occupied by a pharmaceutically inert gas”

Enforcement consequence:

• A competitor could attempt to keep composition/pH/chelator profile constant but modify packaging (headspace gas and container seal type). Such changes can be outcome-determinative on literal infringement.

Litigation posture:

• Patent owners typically frame this element as part of the “using” step in the method, meaning the healthcare provider’s administration must involve the accused packaged product.

What is claim scope for dilution: which aqueous diluents matter?

Dependent claims specify:

• “aqueous solution comprises at least one of 5% dextrose, 0.45% sodium chloride, and water for injection” (claims 2, 7, 12)

Exposure map:

• If the accused dilution uses only other diluents (not listed) and is not covered by any broader diluent language, it may fall outside those dependent claims.
• Because the independent claims include “diluting the composition in an aqueous solution” without restricting diluent identity, a broader infringement theory can still exist depending on which claim is asserted.

How does the patent’s dosing regimen align with standard acetylcysteine protocols? What is covered legally?

The claimed regimen matches the commonly used 3-dose acetylcysteine protocol:

• 150 mg/kg loading
• 50 mg/kg second dose
• 100 mg/kg third dose
• total 300 mg/kg

Legally, the patent does not claim “acetylcysteine overdose treatment” generally. It claims the use of a specific stable, IV, chelator-free, pH-bounded composition in inert-gas airtight packaging, plus dilution.

Key litigation lever:

• If accused products use the same clinical dosing but differ on formulation and packaging, exposure depends on whether the formulation/container elements are met.

Which adverse outcomes are covered: overdose treatment vs overdose-induced liver damage vs liver failure?

• Claim 1/6: treating acetaminophen overdose (general)
• Claim 10/15/16: treating acetaminophen overdose-induced liver damage and further specifying liver failure, including acute liver failure

Clinical-to-legal translation:

• A manufacturer may design a label or clinical indication that attempts to avoid the narrower “liver damage/liver failure” dependent claim predicates. Whether those label efforts defeat infringement depends on how courts evaluate “method of treating” and actual patient treatment facts.

What patents likely surround US 8,399,445: formulation stability, chelator-free NAC, container inert gas, and acetylcysteine IV concentration?

The provided claim text is specific enough to infer typical neighboring IP clusters in the acetylcysteine IV landscape:

1) IV acetylcysteine formulation stability patents

Common adjacent claim themes in this space:

• specific concentration ranges (e.g., 20 mg/mL vs 200 mg/mL vs other)
• pH adjustments
• chelator/salt selection
• excipient suites for stability and compatibility

US 8,399,445 is unusually focused on chelator-free and on airtight inert-gas headspace packaging.

2) Packaging and oxygen/moisture exclusion claims

The inert-gas headspace limitation points to:

• sensitivity to oxidation or degradation pathways
• stability enhancements via container environment control

3) Method-of-use patents for acetaminophen overdose dosing regimens

Those are common, but US 8,399,445 differs by binding the “using” step to a particular composition and packaging.

4) Dilution and administration route claims

Many NAC patents cover dilution/protocol steps; this one binds dilution to the specific composition.

How strong is the patent estate around US 8,399,445 for enforcing against generics or authorized generics?

From a scope perspective, strength is driven by four enforceability factors:

1. Multiple independent technical constraints must be met (concentration, pH window, chelator-free, inert-gas headspace, airtight packaging, dilution, and administration).
2. Those constraints are not purely “method only”; they embed product attributes.
3. Dependent claims narrow further (specific diluent list, pH subrange, and dosing schedule).
4. The patent’s specificity can reduce prior-art overlap, but it also creates design-around opportunities if a competitor changes one or more of the formulation or packaging constraints.

What US generic entry risks exist for acetaminophen overdose treatment using acetylcysteine under US 8,399,445?

Generic or biosimilar-like risk framing (small molecule vs biologic)

Acetylcysteine is not a biologic, so “biosimilar” risk is not the right lens. The practical risk is:

• ANDA-style formulation differentiation
• label carve-outs are often insufficient if the method claims are triggered by actual treatment using a covered product

Design-around routes likely considered by competitors

Competitors can attempt to avoid literal scope by altering:

• acetylcysteine concentration outside the claim bounds
• pH outside the 6 to 7.5 window
• elimination or addition of excipients that affect “chelator-free” characterization
• packaging so headspace is not an inert gas, or the container is not “airtight” in the claimed sense
• dilution procedure such that claimed dependent diluent constraints are not met

Most sensitive variable: inert-gas headspace in airtight containers, because this is a packaging-level constraint that can be hard to change without formulation and manufacturing process revisions.

What Orange Book status questions matter for enforcement around this patent?

This analysis cannot determine Orange Book listing status for US 8,399,445 because the underlying patent-to-product mapping (US listing, NDA number, listed drug, or method-of-use vs drug product patent category) is not provided in the prompt. Under typical regulatory practice, if US 8,399,445 is listed for a covered NDA, it could drive Paragraph IV risk during ANDA submissions.

What patent expiration or exclusivity timeline applies to US 8,399,445?

This analysis cannot compute exact expiration or adjusted dates because the prompt does not provide filing date, priority claim(s), or patent term adjustment data. Without those, any exclusivity timeline would be speculative.

Key Takeaways

• US 8,399,445 is a highly specific method-of-treatment patent tied to a stable aqueous IV acetylcysteine composition with:
  • 200 mg/mL (claim 1) or 200-250 mg/mL (claim 6),
  • chelator-free formulation,
  • pH 6 to 7.5 (with narrower <7.0 dependent claims),
  • airtight container with inert-gas headspace, and
  • dilution in aqueous solution before administration.
• Dependent claims add standard 3-dose NAC regimen terms (150/50/100 mg/kg total 300 mg/kg) and diluent identity options.
• The packaging limitation (inert-gas headspace) creates a meaningful design-around axis that can reduce exposure even when clinical dosing is identical.
• The liver-failure dependent coverage (including acute liver failure) tightens indication-to-claim mapping through treatment outcome framing.

FAQs

1. Does US 8,399,445 cover acetaminophen overdose treatment with any acetylcysteine IV product?
   No. Literal coverage requires the claimed formulation attributes (concentration, chelator-free, pH) and container headspace/airtight packaging plus the dilution and administration steps.

2. If a product has the correct pH and concentration but uses different excipients, does it avoid infringement?
   If the excipients cause the composition to include a “chelating agent,” it can still fall within the claim’s “free of chelating agents” boundary depending on whether the excipient qualifies as a chelator under claim interpretation.

3. Can competitors design around by changing the dosing schedule?
   Changing the dosing schedule may avoid dependent claim coverage that specifies 150/50/100 mg/kg, but independent claim scope depends on whether the regimen is required as part of the asserted claim.

4. What element is most likely to be a manufacturing barrier for generic challengers: formulation or packaging?
   The inert-gas headspace in an airtight container is a packaging/manufacturing variable and is often harder to change than excipient and pH targets.

5. Does the patent’s “liver failure” language limit infringement to patients with confirmed liver failure?
   Dependent claims frame the method around liver damage and liver failure; actual patient outcomes and treatment context drive whether those narrower dependent theories apply.

References

1. US Patent 8,399,445. (Claims provided in prompt text).

Drugs Protected by US Patent 8,399,445

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 8,399,445

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2006282030
Canada	2619441
China	101242824
China	102266316
European Patent Office	1928449
Hong Kong	1123972