Patent 6,599,530: Scope, claim-by-claim coverage, and US patent landscape for entacapone/nitecapone oral compacted tablets (croscarmellose sodium and dissolution-controlled formulations)

United States Patent 6,599,530 is a US formulation and process patent focused on an oral compacted tablet containing entacapone or nitecapone (or salts) and croscarmellose sodium at a specified high level, with optional dissolution-performance thresholds and a manufacturing workflow built around mixing, compacting/crushing to granules, adding glidant/lubricant, and compressing. The protection is centered on (i) the excipient level of croscarmellose sodium (minimum 6% by weight; optional 8–16% and 10–14% sub-ranges), (ii) tablet form, (iii) specific entacapone dose bands (5–400 mg; optional 100–200 mg; optional ~200 mg), (iv) defined dissolution outcomes for particular excipient levels and media, and (v) a specific granulation-compaction process sequence. Downstream freedom-to-operate for generic or reformulation products typically hinges on whether the proposed product uses croscarmellose sodium at or above the claimed threshold and whether it matches the dissolution and dose/compaction/process features tied to dependent claims.

What does US Patent 6,599,530 claim cover for entacapone tablets (scope of protection)?

Core claim scope: a tablet made by compaction/compression that includes:

Active: entacapone or nitecapone, or pharmaceutically acceptable salt of either
Disintegrant/excipient: croscarmellose sodium at ≥6% by weight
Optional dependent narrowing to excipient ranges, specific dissolution performance, and specific dose ranges

Claim 1 (independent): the main infringement “hook”

Claim 1 defines the broadest composition:

“An oral compacted composition in the form of a tablet”
Contains: entacapone, nitecapone, or salt
Contains: croscarmellose sodium ≥6% by weight

This is the primary structural requirement. A product that omits croscarmellose sodium or uses it below 6% by weight avoids Claim 1’s literal scope. Products that meet or exceed the threshold face exposure unless they fall outside “oral compacted composition” language or avoid the tablet/compaction characterization.

Claims 2–3: narrowing by active identity

Claim 2 limits to entacapone
Claim 3 limits to nitecapone

If a product uses entacapone, Claim 2 becomes the relevant dependent claim path. Nitecapone-based products would track Claim 3.

Claim 4–5: excipient sub-ranges as additional barriers

Claim 4: croscarmellose sodium 8–16%
Claim 5: croscarmellose sodium 10–14%

These claims are narrower than Claim 1 but useful for showing multiple layers of protection. A product at 7% meets Claim 1 but not Claim 4/5. A product at 12% potentially meets all three (Claim 1 + 4 + 5).

How do the dissolution-defined dependent claims limit coverage (claims 6–7)?

Claims 6 and 7 are designed to capture formulations that not only use high croscarmellose sodium, but also deliver specific in vitro dissolution performance under defined testing conditions.

Claim 6: entacapone with ~6% croscarmellose sodium and specific dissolution at pH 5.8?

Claim 6 recites:

Entacapone (or salt)
about 6% by weight croscarmellose sodium
Dissolution: “at least about 65% over about 30 minutes”
Test method: basket method at 100 rpm, 900 ml phosphate buffer pH 58 (as written)

Because the claim includes both the excipient level and a dissolution threshold in a specified medium, infringement analysis must map product dissolution testing to the claim test conditions (medium pH, method, time, and acceptance percent).

Claim 7: entacapone with ~9% croscarmellose sodium and high dissolution

Claim 7 recites:

Entacapone (or salt)
about 9% by weight croscarmellose sodium
Dissolution: “at least about 92% over 30 minutes”
Basket method at 100 rpm, 900 ml phosphate buffer at pH 5.8 (as written)

Claim 7 functions as an evidentiary and technical narrowing. A generic that stays above 6% but does not meet these dissolution outcomes under the stated conditions may still infringe Claim 1/4/5 but not necessarily Claim 6/7.

What dosing ranges are protected (claims 8–11)?

The patent includes dose band limitations that can matter in marketing authorizations and product strengths.

Claims 8–10: broad and medium entacapone dose ranges

Claim 8: 5–400 mg entacapone or salt
Claim 9: 100–200 mg entacapone or salt
Claim 10: about 200 mg

Claim 11: combination of dose band and excipient threshold

Claim 11 states:

Tablet containing 100 mg or 200 mg entacapone or salt
with croscarmellose sodium ≥6%

If a competitor launches at 200 mg with ≥6% croscarmellose, Claim 11 becomes a direct dependent anchor.

What manufacturing process is claimed for making the tablet (claims 12–18)?

Claim 12 is a process-by-steps claim. It can support infringement where a manufacturer uses the claimed workflow, even if the final tablet is similar, depending on proof of process performance.

Claim 12 (independent process)

Method of preparing an oral compacted tablet:

Mixing entacapone/nitecapone (or salt) + one or more auxiliary agents + croscarmellose sodium to obtain a first mixture
Compact and crush the first mixture one or more times to obtain a plurality of granules
Add lubricant, glidant, or mixture to granules to obtain a second mixture
Compress second mixture into a tablet

This claim is structured to distinguish from wet granulation and other routes by emphasizing compacting/crushing into granules before adding lubricant/glidant and final compression.

Claim 13–14: excipient sub-ranges in the process

Claim 13: croscarmellose sodium 8–16%
Claim 14: 10–14%

Claim 15: auxiliary agent solubility limitation

At least one auxiliary agent is water soluble

Claims 16–18: entacapone dose ranges in the process

Claim 16: 5–400 mg
Claim 17: 100–200 mg
Claim 18: about 200 mg

Infringement risk for process claims is tied to whether the accused method uses compacting/crushing, includes croscarmellose sodium at the claimed level, and includes at least one water-soluble auxiliary agent (if Claim 15 is asserted).

What method-of-use protection is provided (claims 19–20)?

Claim 19 (method of inhibiting COMT)

“A method of inhibiting catechol-O-methyltransferase”
Administer to a patient in need an oral compacted composition of Claim 1

This is the functional therapeutic endpoint. The use claim is dependent on Claim 1 composition scope. If Claim 1 is not met, Claim 19 typically fails as a derivative claim.

Claim 20

Specifies that the composition comprises entacapone (or salt)

How would a generic or reformulation avoid infringement of US 6,599,530?

Because the claims are excipient- and compaction-centric, the most direct avoidance routes are:

Lower croscarmellose sodium below 6% by weight to exit Claim 1 literal scope.
Risk remains if a court treats “at least 6%” with tolerances and the product’s measured content falls within the claimed range in practice.
Use entacapone but change tablet architecture and manufacturing steps to avoid “oral compacted composition” characterization and the specific compact-and-crush workflow in Claim 12, especially if process compliance is a factual issue.
Avoid matching dissolution thresholds tied to specific excipient levels in Claims 6 and 7.
Note this does not automatically avoid Claim 1, but it can reduce asserted claim sets and damages leverage.
Launch strengths outside the dose-dependent claim bands where relevant (100 mg and 200 mg are explicitly called out in dependent form).
Claim 1 itself does not recite dose, so strength alone may not fully clear risk if croscarmellose is ≥6%.

Claim landscape mapping: which claim sets a company is most likely to face?

Product feature	Claim anchor(s)	What it covers
Tablet with entacapone/nitecapone + croscarmellose sodium ≥6%	Claim 1	Broadest composition coverage
Entacapone specifically	Claim 2	Dependent composition
Nitecapone specifically	Claim 3	Dependent composition
8–16% croscarmellose	Claim 4	Intermediate excipient range
10–14% croscarmellose	Claim 5	Tight excipient range
~6% croscarmellose + specific dissolution level	Claim 6	Technical dissolution performance limitation
~9% croscarmellose + specific dissolution level	Claim 7	Technical dissolution performance limitation
5–400 mg entacapone	Claim 8	Dose band
100–200 mg entacapone	Claim 9	Dose band
~200 mg entacapone	Claim 10	Dose band
100 mg or 200 mg + ≥6% croscarmellose	Claim 11	Dose + excipient combination
Compact-and-crush granules + compress	Claim 12	Manufacturing process method
8–16% excipient in process	Claim 13	Process excipient range
10–14% excipient in process	Claim 14	Process excipient range
Water-soluble auxiliary agent	Claim 15	Process component limitation
Dose bands in process	Claims 16–18	Dose + process linkage
Administer for COMT inhibition using Claim 1 composition	Claim 19	Method of use derivative claim
Entacapone for COMT inhibition	Claim 20	Use claim dependent narrowing

How strong is the patent estate for this technology around 6,599,530 (what is likely “the estate”)?

This answer is constrained to the information provided. You supplied the claim text for US 6,599,530 but not the patent bibliographic record (filing date, priority, assignees, publication history, continuation/divisional lineage), prosecution history, citation set, or the surrounding US/EP/WO family members. Without those identifiers, a complete landscape across related US continuations, divisional filings, continuation-in-part branches, and foreign counterparts cannot be reliably produced.

What can be stated from the claims alone: the patent is tightly focused on:

croscarmellose sodium loading thresholds
dissolution performance in defined phosphate media using basket dissolution at 100 rpm
a compaction/crushing granule generation process before compression
COMT inhibition use tied to the composition

This implies the surrounding family, if any, may include incremental formulation variants (different disintegrant levels or dissolution specs) and potentially process refinements. But identifying actual patents, their claims, and their expiration timelines requires bibliographic data and patent family mapping that is not present in the prompt.

Orange Book, FDA exclusivity, and Paragraph IV risk: what can be concluded from the provided claims?

No Orange Book listing status, NDA/ANDA numbers, FDA reference product identity, or FDA exclusivity dates were provided. Without the regulatory linkage, it is not possible to determine:

which reference listed drug (RLD) US 6,599,530 is tied to
whether it is an Orange Book patent for a specific NDA/ANDA
whether it expires earlier due to filing/adjustment structures
the likely Paragraph IV claim strategy against it

The only defensible point from claim content: the patent is an excipient- and dissolution-parameter formulation, which typically maps to reformulation risks more than to active-ingredient “composition of matter” risks.

Competitive landscape for entacapone oral tablets: what claim features drive design-around decisions?

Even without named competitors, the design-around logic is clear from the claim structure:

Disintegrant loading is the high-leverage variable.
If a competitor uses croscarmellose sodium below 6% by weight, it avoids Claim 1. If it uses ≥6%, it must address Claim 1 and dependent excipient range claims.
Dissolution specs at specific croscarmellose levels can become the battleground for dependent claims.
Claim 6 and Claim 7 create a measurable performance target tied to excipient level.
Manufacturing method can be litigated via process discovery.
If a process differs from the claimed “compact and crush to granules” sequence, Claim 12 may be harder to assert than composition-only theories, depending on how the product is made.
Dose strength matters for dependent claim coverage but not for Claim 1.
If the product strength is outside 100 mg/200 mg, Claim 11 is less relevant, but Claim 1 still may apply if excipient and tablet/compacted criteria are met.

Key Takeaways

US 6,599,530 protects a tablet formulation of entacapone or nitecapone (or salts) with croscarmellose sodium at ≥6% by weight.
Dependent claims tighten coverage by croscarmellose sodium ranges (8–16%, 10–14%), dose bands (5–400 mg; 100–200 mg; ~200 mg), and defined dissolution performance tied to specific excipient levels and basket dissolution in phosphate buffer.
A separate layer covers a specific preparation process emphasizing mixing, then compacting and crushing to granules, then adding lubricant/glidant, then compressing.
Method-of-use claims cover COMT inhibition via administering the Claim 1 composition (with entacapone-specific narrowing in Claim 20).
Design-around centers on reducing croscarmellose sodium below 6%, changing the compaction/crushing process, and failing the dissolution thresholds that appear in dependent claims.

FAQs

Can a tablet with croscarmellose sodium slightly below 6% avoid US 6,599,530 Claim 1 literal infringement?
If a product meets the croscarmellose ≥6% requirement, does it automatically infringe dependent dissolution claims (6 and 7)?
How does changing granulation from compact-and-crush to wet granulation affect infringement of Claim 12?
Do entacapone tablets at strengths other than 100 mg or 200 mg still risk coverage under Claim 1?
Is COMT inhibition under Claim 19 contingent on meeting the exact composition limits of Claim 1?

References (APA)

United States Patent 6,599,530 (claims provided in prompt).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	021806	⤷ Start Trial
Austria	256454	⤷ Start Trial
Australia	5748299	⤷ Start Trial
Australia	746889	⤷ Start Trial
Bulgaria	105436	⤷ Start Trial
Bulgaria	65041	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,599,530

Summary for Patent: 6,599,530