United States Drug Patent 6,878,386 (amoxicillin/potassium clavulanate modified-release) | Scope, Claim Strength, and US Landscape

United States Patent No. 6,878,386 claims methods of treating bacterial infections in humans using ~2000 mg amoxicillin + ~125 mg potassium clavulanate administered at approximately 12-hour intervals from a modified-release formulation that meets specific pharmacokinetic (PK) targets for amoxicillin and, in dependent claims, specific in vitro dissolution targets. The patent’s technical claim strategy centers on PK matching (Cmax, duration of mean concentration, and AUC relative to immediate release) and, in other claim sets, dissolution window compliance in a defined USP paddle method, plus a bi-phasic release structure that drives immediate clavulanate release with modified amoxicillin exposure.

What is the claimed invention (core method scope)?

Is the patent claiming a drug product, or a clinical dosing method?

It claims a method of treating (medical use), not an apparatus or manufacturing method. The operative claim elements are:

Indication: “treating a bacterial infection in a human”
Patient dosing: about 12 hours regimen interval
Dose: about 2000 mg amoxicillin and about 125 mg potassium clavulanate
Formulation: “modified release” with PK constraints for amoxicillin, and “immediate release of potassium clavulanate”
Target PK metrics:
- Mean Cmax of amoxicillin threshold(s) (e.g., ≥12 μg/mL, ≥16 μg/mL)
- Mean plasma amoxicillin concentration floor (e.g., ≥4 μg/mL for ≥4.2 to 4.8 hours, also about 6 hours in later dependent claims)
- AUC ratio relative to same amount immediate release formulation: ≥80% (and dependent tiers ≥90%, ≥100%, ≥110%, ≥120%)

This combination functions like a “functional product-by-performance” claim: infringement turns on whether the administered formulation produces the claimed PK profile under the method conditions.

Claim anatomy and practical “who is in scope” test

What are the major independent claim themes?

The independent claim set you provided is effectively organized around three overlapping performance models:

General modified-release PK model (independent claim 1; later independent claim 28)
Dissolution profile constrained modified-release PK model (independent claim 9; dependent dissolution windows 10-14; plus PK-dependent claim extensions 15-21)
Bi-phasic modified-release architecture with immediate clavulanate and immediate + slow amoxicillin phases (independent claim 40; dependent architecture 56-58, 64-71, 67, 68-80)

Which PK constraints dominate claim coverage?

Across the independent and dependent claims, the repeating PK thresholds define the likely “lock points” for infringement.

Common dosing and PK structure

Dose: 2000 mg amoxicillin / 125 mg potassium clavulanate
Interval: ~12 hours
Requirement: modified release formulation adapted to achieve:
- Mean Cmax ≥12 μg/mL (claim 1, also claim 40)
- or Mean Cmax ≥16 μg/mL (claims 6, 28, 48)
- Mean concentration ≥4 μg/mL for ≥4.2 hours (claim 1, also claim 40, 28) and elevated duration variants:
- ≥4.4 hours (claim 2, 16, 33)
- ≥4.8 hours (claim 3, 7, 17, 34)
- about 6 hours (claim 35, 45, 58)
- AUC ≥80% vs immediate release over same interval (claim 1, 9, 28, 40, 58) with tiered dependent thresholds:
- AUC ≥90% (claim 29, 59)
- AUC ≥100% (claim 30, 60)
- AUC ≥110% (claim 31, 61)
- AUC ≥120% (claim 32, 62, 63)

Key structural PK ambiguity (important for landscape mapping)

Claims use mean and relative AUC to an “immediate release formulation over the same dosage regimen interval.” That structure can be met by different modified-release designs if they are calibrated to the specified systemic exposure.

Dissolution profile scope: the most concrete chemistry-to-performance hook

Does the patent define a specific in vitro dissolution test?

Yes. The dissolution-constrained claim set uses a specific method:

USP paddle apparatus 2, USP 23 (1995), 37.0 ± 0.5°C
900 mL deionised water
paddle speed 75 rpm
Dissolution metrics for amoxycillin content:
- 45% to 65% dissolved within 30 min (claim 9; also claim 25)
- 50% to 75% within 60 min (claim 10)
- 55% to 85% within 120 min (claim 11)
- 70% to 95% within 180 min (claim 12)
- 70% to 100% within 240 min (claim 13)
- narrowed: 75% to 100% within 240 min (claim 14)
Dependent claim set ties these dissolution properties back to PK requirements (e.g., claims 15-21 and others).

What does this mean for competitive products?

Products can potentially avoid dissolution-limited claim coverage by:

missing one of the dissolution window percentages at a specific time point; or
selecting release strategies that meet PK but do not match the defined paddle method dissolution curve.

But because the independent claims also include PK constraints without requiring the dissolution profile, dissolution compliance is not the only infringement route.

Bi-phasic formulation architecture: immediate clavulanate plus phased amoxicillin

Is there a structural claim hook for release sequencing?

Yes. The bi-phasic independent claim model requires:

Immediate release of potassium clavulanate
Biphasic modified release of amoxicillin:
- immediate release phase for a first part of amoxicillin
- slow release phase for a second part of amoxicillin

Key dependent architecture details include:

Immediate release phase formed by excipients enabling immediate release of:
- all potassium clavulanate
- first part of amoxicillin
Slow release phase: second part of amoxicillin formulated for slow release (claim 76; also claim 57)

What are the quantitative phase splits?

Claim 68 provides a dosage composition breakdown (for a two-tablet unit with dose tolerances):

Two tablets (about 1000 mg ± 5% amoxycillin each unit? text states total per two tablets):
- ~563 mg ± 5% amoxycillin in the immediate release phase
- potassium clavulanate in immediate phase: ~62.5 mg ± 5%
- ~438 mg ± 5% amoxycillin in the slow release phase

These values function as a target blend strategy and help map whether a competitor’s dosage form has comparable phased drug loading.

What amoxicillin forms are explicitly claimed?

The patent specifies salt/crystal form possibilities:

Modified/slow phase amoxicillin:
- sodium amoxycillin (claim 69)
- crystallized sodium amoxycillin (claim 70)
Immediate phase amoxicillin:
- amoxycillin trihydrate (claim 71)
- also alternative combinations appear in claims 77 and 78-79.

Does the claim anchor to a figure or named formulation?

Claim 67 requires a PK profile “substantially as shown in FIG. 5, formulation A.” This is a common infringement analysis pivot: a competitor can be captured if its clinical PK resembles the claimed reference profile.

Micro-scope: organism and respiratory indications

Does claim scope limit to specific bacteria?

Yes, several dependent claims narrow the claimed bacterial infection organisms:

S. pneumoniae
H. influenzae (note: your text includes “H. infiuenzae” in some claim numbers, but context indicates the same organism)
M. catarrhalis (claims 5, 22, 26, 38, 41, 65, 81, etc.)

Does the patent cover resistant strains?

For S. pneumoniae, dependent claims require:

“drug resistant and penicillin resistant” (claims 23, 27, 39, 42, 81)

Does it specify respiratory tract infections and named clinical syndromes?

Yes:

“respiratory tract infection” (claims 53, 72, 83, 85-86, 88, 91, 92)
specific examples:
- CAP: community acquired pneumoniae
- AECB: acute exacerbation of chronic bronchitis
- ABS: acute bacterial sinusitis (appearing in claims 54, 73, 84, 86, 89, 92, 93)

This does not narrow the independent claims by itself, but it matters for infringement litigation and for exclusivity analysis of label-level coverage.

Dosage regimen duration: 7 to 14 days

How long is the method course?

Dependent claims specify:

dosing regimen administered over 7 to 14 days (claims 24, 55, 74, 82, 87, 90, 94 and related numbers you included)
one claim variant shows 7 to 4 days (claim 93 ends with “7to 4days”; likely a transcription issue in your text, but it is present as written)

In a typical landscape assessment, duration limits matter because they align with label dosing for certain infections and could support non-infringement if another regimen is used.

Claim duplication and redundancy: what the number-heavy set implies for enforcement

What is the practical effect of the repetitive claim ladder?

Your claim list shows multiple near-duplicates that vary only:

Cmax threshold (≥12 vs ≥16 μg/mL)
time above mean concentration (≥4.2, ≥4.4, ≥4.8 hours, “about 6 hours”)
AUC threshold tiers (≥80%, ≥90%, ≥100%, ≥110%, ≥120%)
amoxycillin dissolution time windows (30, 60, 120, 180, 240 min bands)
formulation architecture (modified release vs bi-phasic)

This creates overlapping infringement “fall-throughs” where one defendant product may meet some thresholds but not others; the set is structured so that meeting key performance targets can land multiple dependent claims at once.

Infringement “design-around” paths for generic or new modified-release competitors

What design changes most likely avoid the claims?

Based on the claim language, avoiding infringement would likely require at least one of the following:

PK avoidance:
- fail to achieve mean Cmax ≥12 μg/mL (or ≥16 μg/mL where relevant)
- reduce time with mean amoxicillin concentration ≥4 μg/mL below the claimed durations
- bring AUC relative to immediate release below the claimed thresholds (i.e., <80%, or below higher dependent tiers)
Release sequencing avoidance:
- change formulation so that potassium clavulanate is not “immediate release” relative to claimed structure, or shift the amoxicillin release scheme so the PK profile does not match the reference “substantially as shown” figure.
Dissolution curve avoidance (for the dissolution-constrained claim set):
- miss the specified USP paddle dissolution ranges at 30/60/120/180/240 minutes.
Dose/interval avoidance:
- move away from the about 2000 mg / 125 mg dose and about 12-hour interval pairing.
Indication/regimen avoidance:
- treat infections in a manner outside dependent organism or duration constraints (where enforceability depends on proving the method claim elements, including organism and regimen).

US patent landscape mapping: how to position this patent among competing exclusivity layers

What “layer” is this patent in?

This is a method-of-treatment patent tied to:

a known antibiotic class (amoxicillin + clavulanate),
a specific dosing regimen,
and a modified-release PK/dissolution performance fingerprint.

In the US ecosystem, this typically sits alongside:

compound or composition patents for amoxicillin/clavulanate salts and combinations,
formulation/matrix control patents for modified release,
and later method-of-use patents tied to particular performance targets or patient subsets.

Where does 6,878,386 likely sit relative to product generations?

Given the emphasis on:

amoxicillin at high dose with clavulanate immediate release,
twice-daily regimens,
extended exposure maintained around ≥4 μg/mL for ~4.2 to 4.8 hours or about 6 hours,
and “biphasic modified release,”

it aligns to the type of modified-release strategy used to support higher amoxicillin exposure in a mixed release tablet while keeping clavulanate early exposure. Competitors aiming for “same PK” generics would be at risk if they match those thresholds.

Scope summary by claim clusters (quick reference)

Claim cluster	Key limitations	What an accused product must show
Core method (e.g., claim 1)	12-hour interval; 2000 mg amoxicillin + 125 mg clavulanate; modified release with immediate clavulanate; amoxicillin PK: mean Cmax ≥12; mean concentration ≥4 μg/mL for ≥4.2 hours; AUC ≥80% vs immediate release	Clinical PK matching thresholds under the same dosing regimen
Elevated Cmax variants (claims 6, 28, 48)	Cmax threshold increased to ≥16 μg/mL	Must reach the higher systemic peak
Extended duration variants (claims 2-3, 15-17, 33-35)	mean concentration ≥4 μg/mL for ≥4.4, ≥4.8, or about 6 hours	Must maintain exposure for the specified period
AUC ladder (claims 29-32, 59-63)	AUC floor increased (≥90%, ≥100%, ≥110%, ≥120%)	Must match relative exposure vs immediate release reference
Dissolution constrained (claims 9, 10-14, 25)	USP 23 paddle apparatus 2 in water at 37°C; dissolution windows at 30/60/120/180/240 minutes	In vitro dissolution matching the defined percent ranges
Bi-phasic release architecture (claims 40, 57, 68, 76-80)	immediate clavulanate; immediate + slow amoxicillin phases; quantitative phase split; specific salt/crystal forms	Formulation must implement phased release and produce the claimed PK

Key Takeaways

The patent claims dosing methods for amoxicillin/potassium clavulanate with a modified-release PK profile and immediate clavulanate release, at ~2000 mg / 125 mg every ~12 hours.
The enforceable “performance locks” are PK-based: mean Cmax thresholds, duration with mean amoxicillin ≥4 μg/mL, and AUC relative to immediate release at ≥80% with dependent tiers up to ≥120%.
A second claim path uses in vitro dissolution windows defined by USP paddle apparatus 2 (37°C, 900 mL water, 75 rpm) and explicit percent dissolution ranges through 240 minutes.
A third path is structural: biphasic formulation requiring immediate clavulanate and phased amoxicillin release, with dependent claims specifying phase splits and amoxicillin salt/crystal forms.
Landscape risk for competitors concentrates on products that match both the PK thresholds and the release/dissolution behavior for amoxicillin in the claimed regimen and dosing form.

FAQs

1) Does 6,878,386 require a specific bacteria species in all claims?

No. The species list (e.g., S. pneumoniae, H. influenzae, M. catarrhalis) appears in dependent claims; the broad independent method language is “bacterial infection,” with organism specificity added in narrower claims.

2) What PK endpoints are central to claim scope?

The claims emphasize amoxicillin Cmax, mean plasma amoxicillin concentration duration (≥4 μg/mL for specified hours), and AUC ratio versus immediate release at the same dose interval (≥80% and dependent thresholds).

3) Does the patent define the dissolution method in vitro?

Yes. It defines USP apparatus 2 paddle, 37.0 ± 0.5°C, 900 mL deionised water, 75 rpm, and specific amoxycillin dissolution percent ranges at 30 to 240 minutes.

4) Is potassium clavulanate required to be immediate release?

Yes. The method claims are adapted so that the dosage provides “immediate release of the potassium clavulanate,” while amoxicillin is modified release.

5) What formulation design features are explicitly claimed in the biphasic model?

Dependent claims describe immediate + slow amoxicillin phases, including quantitative phase loading and specific salt/crystal form examples (e.g., crystallized sodium amoxycillin in the slow phase; amoxicillin trihydrate in the immediate phase).

References

United States Patent 6,878,386, “Method for treating bacterial infection using modified release amoxicillin and immediate release potassium clavulanate.” (Claim text provided in prompt).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
African Regional IP Organization (ARIPO)	1806	⤷ Start Trial
Argentina	031068	⤷ Start Trial
Austria	242629	⤷ Start Trial
Austria	4327	⤷ Start Trial
Australia	5702000	⤷ Start Trial
Australia	5837500	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Summary for Patent: 6,878,386