United States Patent 6,080,428: Claim Scope, Niacin Exclusivity, and Patent Landscape

United States Patent No. 6,080,428 covers once-daily evening or nighttime treatment of hyperlipidemia with oral solid nicotinic acid, including sustained-release formulations using hydroxypropyl methylcellulose, povidone or another water-soluble binder, and stearic acid or magnesium stearate. The patent was directed to the formulation and dosing regimen associated with extended-release niacin products, particularly Niaspan.

The claims are method-of-treatment claims, not composition claims standing alone. A product is not infringed merely because it contains niacin and the listed excipients. Liability requires use of the product in the claimed treatment regimen, although prescribing information, labeling, physician instructions, and actual use can establish method infringement.

What patents protect the once-daily evening dosing of nicotinic acid?

U.S. Patent 6,080,428 protects a combination of four core elements:

Treatment of a hyperlipidemic patient.
Administration of an effective antihyperlipidemic amount of nicotinic acid.
Once-daily administration in the evening or at night.
Administration in an oral solid dosage form.

Dependent claims add dosage, release-rate, excipient, and manufacturing-composition limitations.

Claim group	Principal limitation	Commercial significance
Claim 1	Once-daily evening/night oral solid nicotinic acid	Broadest independent treatment claim
Claim 2	Approximately 250-3,000 mg nicotinic acid	Covers common therapeutic niacin doses
Claim 3	Little or no serious liver damage	Functional safety limitation
Claim 4	Release rate of approximately 2%-25% per hour	Targets controlled-release products
Claim 5	5-50 parts HPMC per 100 parts tablet	Hydrophilic matrix formulation
Claims 6-7	Sustained-release tablet with 1-4% binder; binder may be povidone	Tablet manufacturing and matrix controls
Claims 8-9	0.5-2.5% lubricant; stearic acid or magnesium stearate	Tablet processing limitations
Claim 10	Once-daily evening/night composition consisting essentially of niacin, HPMC, water-soluble binder and lubricant	Independent formulation-regimen combination
Claims 11-13	Povidone and/or stearic acid	Narrow excipient-specific claims

The patent therefore has two principal protection strategies. Claims 1-9 begin with a treatment method and progressively narrow the formulation. Claims 10-13 focus on a defined composition administered under the same once-daily evening or nighttime regimen.

How broad is claim 1 of U.S. Patent 6,080,428?

Claim 1 is materially broader than the dependent claims because it does not expressly require:

A sustained-release dosage form;
A specified niacin dose;
A stated release rate;
HPMC;
Povidone;
Stearic acid;
Magnesium stearate; or
A particular tablet manufacturing process.

Claim 1 does require an oral solid dosage form and once-daily evening or nighttime dosing. A tablet, caplet, or other oral solid containing nicotinic acid could fall within the literal scope if the remaining treatment limitations are satisfied.

The claim does not expressly require that the formulation be extended-release. That distinction matters. A once-daily immediate-release niacin tablet could face a claim 1 theory if it can provide an effective antihyperlipidemic dose and is directed for evening or nighttime administration. Claims 4-9 are narrower and require additional formulation or release characteristics.

The term “effective antihyperlipidemic amount” is a functional limitation. It generally requires evidence that the administered amount is capable of treating hyperlipidemia, rather than merely showing the presence of niacin in a product.

What formulations are protected by the HPMC and binder claims?

Claims 5 through 13 target hydrophilic matrix tablets. HPMC is the principal matrix-forming excipient. Upon contact with gastrointestinal fluid, HPMC can hydrate and form a gel layer that controls diffusion and erosion of the niacin-containing tablet.

The relevant formulation ranges are:

Parameter	Claimed range or requirement
HPMC	About 5-50 parts by weight per 100 parts by weight of tablet
Binder	About 1-4 parts by weight per 100 parts by weight of tablet
Lubricant	About 0.5-2.5 parts by weight per 100 parts by weight of tablet
Binder identity	Povidone for claims 7, 11 and 13
Lubricant identity	Stearic acid or magnesium stearate for claim 9; stearic acid for claims 12 and 13
Release rate	About 2%-25% per hour under claim 4
Dose	About 250-3,000 mg under claim 2

What does “consists essentially of” mean in claim 10?

Claim 10 uses “consists essentially of,” which is narrower than “comprising” but broader than “consisting of.” The formulation may contain components that do not materially alter the basic and novel characteristics of the claimed niacin matrix system. Other excipients may therefore be permissible, depending on their function and effect on release, stability, and dosage-form performance.

The basic characteristics likely include:

Oral solid delivery of nicotinic acid;
HPMC-controlled release;
A water-soluble binder;
A lubricant; and
Once-daily evening or nighttime administration.

An excipient that materially changes the release profile or defeats the claimed matrix mechanism could create a stronger noninfringement position under claim 10, although the analysis would depend on formulation evidence and claim construction.

Does the patent cover Niaspan?

U.S. Patent 6,080,428 is associated with the controlled-release niacin technology underlying the Niaspan product line. Niaspan was developed and commercialized by Kos Pharmaceuticals and later became part of Abbott Laboratories’ pharmaceutical portfolio. Niaspan received FDA approval as an extended-release niacin product for dyslipidemia.

The patent claims align closely with Niaspan’s commercial characteristics:

Extended-release nicotinic acid;
Once-daily administration;
Bedtime or evening dosing;
Oral tablet delivery;
HPMC-based matrix technology; and
Reduced concern regarding serious hepatotoxicity compared with certain older sustained-release niacin products.

The claims do not, however, establish that every Niaspan tablet satisfies every dependent limitation. A claim chart would need the approved formulation, excipient quantities, release data, and labeling instructions.

When did U.S. Patent 6,080,428 lose exclusivity?

U.S. Patent 6,080,428 issued on June 27, 2000. Its patent term was governed by the 20-year term applicable to post-June 8, 1995 applications, measured from the earliest effective nonprovisional filing date, subject to patent-term adjustment and any applicable patent-term extension under 35 U.S.C. §§ 154 and 156.

Public patent records associate the patent with a late-1990s priority and filing chain. On that basis, the patent’s nominal term ended in approximately 2017, subject to the USPTO’s official term calculation. The patent is no longer a live barrier to generic entry in 2025.

Event	Date or period
Patent issued	June 27, 2000
Technology	Controlled-release oral nicotinic acid
Principal commercial product association	Niaspan
Nominal patent-term end	Approximately 2017
Current status	Expired; no current blocking patent right from this patent

Expiration eliminates the right to sue for post-expiration infringement. It does not eliminate potential historical damages claims for conduct occurring before expiration, subject to the six-year limitations period under 35 U.S.C. § 286.

What is the Orange Book status of U.S. Patent 6,080,428?

The FDA Orange Book lists patents submitted by an NDA holder for an approved drug and identifies patents relevant to approved drug substance, drug product, or method-of-use protection. A patent’s historical Orange Book listing does not extend its term and does not independently prove infringement.

For a Niaspan-related generic challenge, the relevant FDA pathway would have been an abbreviated new drug application under section 505(j) of the Federal Food, Drug, and Cosmetic Act. A generic applicant could have submitted:

Paragraph I certification if no relevant patent information was listed;
Paragraph II certification if the patent had expired;
Paragraph III certification accepting delayed approval until patent expiration; or
Paragraph IV certification asserting that the listed patent was invalid, unenforceable, or would not be infringed.

Because U.S. Patent 6,080,428 has expired, it cannot presently support a Paragraph IV-based launch injunction or an Orange Book-driven approval delay. Historical Orange Book status may still matter for reconstructing earlier generic-entry disputes.

Which companies challenged the Niaspan patent estate?

The Niaspan product was subject to generic competition and patent litigation involving abbreviated-approval applicants. Public reporting and litigation records identify generic-drug companies, including Teva Pharmaceuticals and other ANDA applicants, as participants in disputes involving Niaspan-related patents.

The relevant legal question is not whether a challenger used the same active ingredient. It is whether the proposed product and labeling met the limitations of the asserted claims. For this patent, the most important issues would have included:

Whether the proposed label directed evening or nighttime dosing;
Whether administration was once daily;
Whether the product was an oral solid dosage form;
Whether the formulation used HPMC within the claimed range;
Whether the release rate fell within 2%-25% per hour;
Whether the binder and lubricant matched the dependent claims; and
Whether the asserted claims were valid over prior niacin formulations.

A complete litigation chronology requires the individual district-court dockets, Federal Circuit decisions, settlement documents, and FDA approval records. The claim text alone does not establish which claims were asserted, dismissed, invalidated, or settled.

How strong is the patent estate for U.S. Patent 6,080,428?

Strengths

The patent had several practical strengths during its term:

Claim 1 combined a simple, commercially recognizable regimen with a solid dosage form.
The once-daily evening limitation aligned with branded labeling.
Dependent claims gave the patent holder multiple formulation-specific fallback positions.
HPMC, povidone, stearic acid, and magnesium stearate are common excipients, making formulation overlap technically plausible.
Release-rate and excipient claims could support laboratory-based infringement analysis.

Vulnerabilities

The claims also presented substantial validity and enforcement risks:

Niacin treatment of hyperlipidemia was well known.
Sustained-release niacin formulations were known before the patent.
Once-daily nighttime administration may have been vulnerable to obviousness arguments based on pharmacology, tolerability, and established clinical practice.
“Little or no serious liver damage” in claim 3 may raise written-description, enablement, or indefiniteness issues depending on the specification and prosecution history.
The release-rate limitation requires a defined test method, sampling protocol, medium, apparatus, and calculation method.
The ranges in claims 5, 6, and 8 may be vulnerable to prior-art overlap or lack of criticality if the specification does not demonstrate a meaningful technical effect across the full ranges.
Method claims depend on the accused party’s administration instructions and actual use.

The strongest historical claims were likely those tied to the branded product’s actual label and formulation. The weakest claims are those dependent on broad functional language or ranges without a clearly demonstrated technical distinction over prior art.

What generic launch risks existed?

Before expiration, generic applicants faced three principal risks.

Label-induced infringement

A generic label instructing patients to take the product once daily at bedtime could have supported an induced-infringement theory for claim 1. Removing the nighttime instruction could reduce risk, but it could also create regulatory and clinical problems if the reference product’s safety and efficacy depended on that administration schedule.

Formulation overlap

A generic extended-release niacin tablet could overlap claims 4-13 if it used:

HPMC in the claimed amount;
Povidone as a binder;
Stearic acid or magnesium stearate as a lubricant; and
A release profile within the stated range.

The product’s quantitative formulation data and dissolution testing would be central to the analysis.

Invalidity risk

A challenger could argue that the combination of niacin, controlled release, once-daily dosing, nighttime administration, and conventional excipients was obvious. The patent holder’s response would depend on unexpected results, reduced hepatotoxicity, improved tolerability, dissolution control, and evidence of commercial success tied to the claimed features.

How does this patent compare with competing niacin products?

Product or category	Dosage form	Typical administration issue	Relationship to Patent 6,080,428
Niaspan	Extended-release niacin tablet	Once daily, commonly at bedtime	Closest commercial alignment
Immediate-release niacin	Conventional oral solid	Often multiple daily doses	Less likely to meet once-daily regimen
Sustained-release niacin products	Controlled-release oral solid	Product-specific dosing	Potential overlap depending on formulation
Niacin combination products	Niacin with another lipid-lowering agent	Label-specific	Could implicate method claims if niacin regimen is covered
Prescription niacin alternatives	Different active ingredient or delivery system	Product-specific	Usually outside literal nicotinic-acid claims

The patent does not cover statins, fibrates, bile-acid sequestrants, PCSK9 inhibitors, or other non-niacin lipid-lowering therapies. It also does not create biosimilar risk because nicotinic acid is a small-molecule active ingredient, not a biologic.

What manufacturing and geographic barriers remain?

There is no current manufacturing monopoly based solely on U.S. Patent 6,080,428 because the patent has expired. The historical manufacturing barrier concerned the ability to reproduce:

Uniform HPMC hydration;
Controlled tablet hardness and porosity;
Stable release across the claimed rate range;
Consistent high-dose niacin loading;
Acceptable dissolution performance; and
Low variability in gastrointestinal release.

Patent rights were territorial. A U.S. patent could block qualifying conduct in the United States but did not by itself prevent manufacture, sale, or use in Canada, Europe, Japan, or other jurisdictions. Foreign counterparts required separate term and validity analysis.

What licensing deals and settlement agreements affected the technology?

Kos Pharmaceuticals held the commercial rights associated with Niaspan before its acquisition by Abbott Laboratories in 2006. The acquisition transferred the commercial portfolio, including the Niaspan franchise, but did not extend the statutory term of U.S. Patent 6,080,428.

A patent acquisition is not the same as a generic settlement. Any settlement with an ANDA applicant would require review of the individual case docket and agreement terms to determine:

Whether the generic received an authorized launch date;
Whether the agreement included a license;
Whether the license covered the patent, other Niaspan patents, or both;
Whether the settlement included supply, acceleration, or no-challenge provisions; and
Whether the Federal Trade Commission or court reviewed the agreement.

The supplied claim text does not establish a particular settlement date, entry date, or licensing grant.

Key Takeaways

U.S. Patent 6,080,428 covers once-daily evening or nighttime treatment of hyperlipidemia with oral solid nicotinic acid.
Claim 1 is the broadest claim and does not expressly require sustained release or HPMC.
Claims 4-13 narrow protection to release rates, HPMC, povidone, stearic acid, magnesium stearate, binders, and lubricants.
The patent is associated with the Niaspan controlled-release niacin technology.
The patent issued June 27, 2000 and reached the end of its nominal term around 2017.
It is not a current barrier to generic approval or launch.
The main historical litigation issues were label-induced infringement, formulation overlap, release testing, obviousness, and claim construction.
No biosimilar risk exists because the product is a small-molecule nicotinic-acid drug.
Expiration of this patent does not rule out separate, later-expiring Niaspan formulation, method-of-use, or regulatory exclusivity rights.

FAQs About U.S. Patent 6,080,428

Does U.S. Patent 6,080,428 cover all niacin tablets?

No. It covers specified treatment methods requiring once-daily evening or nighttime administration of oral solid nicotinic acid. A niacin product used under a different regimen may fall outside the claims.

Can an immediate-release niacin tablet infringe claim 1?

Potentially. Claim 1 does not expressly require sustained release. The product would still need to satisfy the treatment, dose-effect, once-daily, evening-or-night, oral-solid, and carrier limitations.

Does claim 10 cover a capsule?

Possibly, if the capsule is an oral solid dosage form and satisfies the composition and administration limitations. The claim does not expressly limit the dosage form to a tablet, although several dependent claims refer to tablet composition.

Is HPMC required for every claim?

No. HPMC is required by claims 5 and 10-13, but claim 1 and several other claims do not expressly require HPMC.

Does expiration eliminate all Niaspan patent risk?

No. It eliminates the barrier created by U.S. Patent 6,080,428. Other patents, regulatory exclusivities, trademarks, formulation patents, or product-specific litigation could have had separate terms.

References

U.S. Patent No. 6,080,428. (2000). Sustained release niacin compositions and methods of treatment. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA.
U.S. Code, 21 U.S.C. § 355. (2024). New drugs.
U.S. Code, 35 U.S.C. §§ 154, 156, 271, 286. (2024). Patent term, patent-term extension, infringement, and limitation on damages.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	289197	⤷ Start Trial
Australia	4751802	⤷ Start Trial
Australia	6348198	⤷ Start Trial
Australia	6454598	⤷ Start Trial
Australia	775967	⤷ Start Trial
Brazil	9815454	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,080,428

Summary for Patent: 6,080,428