United States Patent 5,759,580 (Nebivolol) Scope, Claim Strength, and US Patent Landscape

Executive summary: U.S. Patent 5,759,580 covers a solid oral pharmaceutical composition of nebivolol (or a pharmaceutically acceptable salt) in a “micronized solid form,” with explicit constraints on particle surface area, micronized drug loading (1 to 4%), and formulation variables including wetting agent selection (Polysorbate or sodium dioctylsulfosuccinate), wetting-agent-to-drug ratio (w/w 0.025–0.5), and tablet/dissolution performance (75% in 45 minutes). The claim set is narrow in one key respect (nebivolol must be micronized to a specific surface area ≥ 23×10³ cm²/g) and is formulation-constrained via excipient classes and quantitative ratios. For generic and 505(b)(2) entrants, the main US risk is a composition-of-matter style coverage tied to particle size/surface area and wetting-system constraints, not just “nebivolol tablets.”

What does US Patent 5,759,580 claim for micronized nebivolol tablets?

Core claim structure: The patent is centered on a composition with three technical pillars:

Drug form: nebivolol or nebivolol salt is micronized.
Quantitative micronization metric: micronized nebivolol hydrochloride has specific surface area ≥ 23×10³ cm²/g.
Formulation system: carrier includes conventional solid-tablet excipient classes, with a wetting agent system quantified by w/w ratio to nebivolol.

How Claim 1 sets infringement “gates”

Claim 1 (independent) requires:

A pharmaceutically acceptable carrier with:
- filler
- lubricant
- disintegrant
- binding agent
- wetting agent
Active ingredient: nebivolol or a pharmaceutically acceptable salt
Nebivolol in “micronized solid form” (no numeric threshold in Claim 1 itself)
This composition is directed to a solid oral dosage formulation in downstream claims (Claim 2 and Claim 7).

Practical scope implication: A challenger/generic strategy can’t avoid Claim 1 by changing excipient identity alone because Claim 1 requires the presence of the wetting agent plus the excipient function classes. However, Claim 1 does not, by itself, impose the ≥23×10³ cm²/g threshold or the Polysorbate ratio threshold; those appear in dependent claims.

What dependent claims add that tighten coverage

Claim 3: specifies micronized nebivolol hydrochloride.
Claim 4: requires specific surface area ≥ 23×10³ cm²/g.
Claims 5–6: specify drug loading and wetting-agent ratio.
- Claim 5: micronized nebivolol hydrochloride at 1–4%.
- Claim 6: wetting agent includes Polysorbate, with Polysorbate:w/w nebivolol hydrochloride ratio 0.025–0.5.
Claims 7–9: tablet form and performance:
- Claim 7: tablet
- Claim 9: tablet has dissolution 75% after 45 minutes
Claims 11–17: define excipient “selection lists” (filler/lubricant/disintegrant/binder/wetting agent) and constrain combinations.
Claims 18–20: specify broader wetting-agent ratio ranges (Polysorbate or sodium dioctylsulfosuccinate, depending on claim dependency), narrowing to sub-ranges.

Claim dependency and “design-around” leverage

A key business point is that infringement may hinge on whether an accused product meets:

the surface-area threshold (Claim 4/10), and/or
the wetting ratio (Claim 6, 18–20), and/or
the drug loading (Claim 5), and/or
the dissolution criterion (Claim 9), and/or
a constrained excipient combination (Claims 16–17).

So, even though Claim 1 is broad in excipient-function coverage, the most enforceable hooks for a patentee are typically the numeric constraints in dependent claims.

Which elements are required for infringement of Claim 1 vs dependent claims?

Claim 1 elements checklist

A product maps to Claim 1 if it contains:

nebivolol (or acceptable salt) in micronized solid form
tablet/solid carrier containing:
- filler + lubricant + disintegrant + binder + wetting agent

No quantitative surface area is demanded in Claim 1.

“Higher-risk” dependent claim constraints

Claim 4 / Claim 10 (micronization metric):

Nebivolol hydrochloride specific surface area must be ≥ 23×10³ cm²/g.

Claim 5 (dose fraction within formulation):

Nebivolol hydrochloride 1–4% of the composition.

Claim 6 / Claim 18–20 (wetting ratio):

Polysorbate as wetting agent, 0.025–0.5 w/w Polysorbate:nebivolol hydrochloride.
Wetting-agent ratio ranges in sub-ranges:
- 0.025–0.3 (Claim 19)
- 0.04–0.25 (Claim 20)

Claim 9 (dissolution performance):

75% dissolution after 45 minutes.

Claim 7–8 (tablet and example composition):

Tablet form is required by Claim 7.
Claim 8 provides a specific example-like composition, which can become relevant for validity/interpretation and for mapping to commercial formulations.

What excipients and wetting agents are covered in US 5,759,580?

Claim 1 uses functional language (carrier comprises categories). Dependent claims provide candidate excipients.

Filler options (Claims 11 and 16–17)

Covered filler group includes:

lactose, sucrose, mannitol
maize starch
microcrystalline cellulose
calcium hydrogen phosphate

Claim 17 narrows filler sets (lactose, sucrose, microcrystalline cellulose) with other list constraints.

Lubricants (Claims 12 and 16–17)

Covered lubricants include:

stearic acid
polyethylene glycol
hydrogenated vegetable oil
sodium stearyl fumarate
magnesium stearate
talc
silica

Disintegrants (Claims 13 and 16–17)

Covered disintegrants include:

rice, potato, or maize starch
sodium starch glycolate
croscarmellose sodium

Binding agents (Claims 14 and 16–17)

Covered binders include:

pregelatinized maize starch
polyvinylpyrrolidone
hydroxypropyl methylcellulose (spelled “hydroxpropyl methylcellulose” in the prompt)

Wetting agents (Claims 15 and 16–17)

Wettting agents include:

sodium dioctylsulfosuccinate
polysorbates (explicitly Polysorbate in Claim 6; polysorbate in Claim 18–20 via ratio language)

Why wetting system is the enforcement lever

Claim 6 and Claims 18–20 quantify:

w/w ratio of wetting agent to nebivolol This creates a clear mapping tool for product formulation comparison and can drive faster claim charting than excipient substitution alone.

What are the key quantitative claim thresholds in US 5,759,580?

Parameter	Claim(s)	Threshold / Range	Practical relevance
Specific surface area	Claim 4, 10	≥ 23×10³ cm²/g (2.3×10³ m²/kg)	Determines whether the nebivolol is “micronized” enough to meet the claimed micronization metric
Nebivolol hydrochloride loading	Claim 5	1 to 4% (by weight)	If formulation uses substantially lower/higher API fraction, it may fall outside dependent claims
Polysorbate wetting ratio	Claim 6	0.025 to 0.5 w/w (Polysorbate:API)	Very product-specific for generics
Wetting ratio broader	Claims 18–20	~0.025–0.5 (Claim 18), 0.025–0.3 (Claim 19), 0.04–0.25 (Claim 20)	Supports sub-range targeting in infringement arguments and design-around
Dissolution	Claim 9	75% after 45 minutes	Performance test may be central in establishing claim coverage for tablets

What tablet formulation example is recited, and what does it imply about commercial products?

Claim 8 recites a tablet composition including:

nebivolol hydrochloride: 2.40%
lactose: 61.6%
maize starch: 20.0%
croscarmellose sodium: 6.00%
colloidal anhydrous silica: 0.26%
magnesium stearate: 0.50%
Hypromellose 2910 15 cps: 2.00%
Polysorbate 80: 0.20%
microcrystalline cellulose: 7.00%

Commercial mapping implication: This profile sits within the dependent claim ranges:

API at 2.40%, which is within 1–4%
Polysorbate 80 at 0.20%, which yields a Polysorbate:API ratio of ~0.083 (0.20/2.40), inside 0.025–0.3 and 0.04–0.25 sub-ranges

Even if claim 8 is not strictly required for infringement (as it is dependent), it strongly signals the formulation type and performance target that the patentee intended.

When does US 5,759,580 expire, and what does that mean for generic entry risk?

The prompt does not include the patent’s filing date, priority date, or terminal disclaimer status, which are required to compute an exact US expiration date. Without those dates, an accurate exclusivity/expiration timeline cannot be produced.

Actionable takeaway without a date: For litigation and product clearance, the decisive question is not only “is the patent expired,” but whether an accused generic’s formulation:

meets the ≥23×10³ cm²/g surface-area requirement, and
uses a wetting agent system at 0.025–0.5 w/w relative to API, and
falls within 1–4% API fraction and (for dependent claim coverage) 75% dissolution at 45 minutes.

What is the likelihood that a generic can design around by changing micronization or wetting?

Design-around axis 1: micronization metric

Because specific surface area ≥ 23×10³ cm²/g appears in Claim 4/10, reducing surface area below the threshold is a direct path to avoid those dependent claims. Claim 1 still requires “micronized solid form,” but the numeric guardrail appears only in dependent claims.

Risk posture: If the accused product’s particle-size distribution is challenged in discovery/testing to still meet the surface-area metric, dependent claim risk returns.

Design-around axis 2: wetting-agent ratio

Because wetting-agent ratio is quantified, shifting the Polysorbate/sulfosuccinate ratio outside 0.025–0.5 (and likely outside narrower sub-ranges) reduces dependent claim exposure.

Risk posture: If formulation testing shows overlap in ratio or if claim construction treats “wetting agent” to encompass excipient excipients used for wetting outside the primary ratio, infringement arguments can re-expand.

Design-around axis 3: API loading fraction and dissolution

Moving API fraction outside 1–4% can avoid Claim 5, while changing tablet composition and process parameters can also shift dissolution.

Risk posture: Dissolution is testing-dependent. If a generic’s dissolution profile is designed to match the reference product and lands on 75% in 45 minutes, it can create a performance-based match to Claim 9.

What patent claim themes are likely to be challenged in validity and construction?

Given the claim language, typical pressure points include:

Claim construction of “micronized solid form” in Claim 1 versus the numeric surface area in Claims 4/10.
Measurement methodology for specific surface area testing (surface area tests can differ by method, conditioning, and particle handling). The patent ties to a numeric value, which tends to invite test-method fights.
Functional excipient language in Claim 1 can be broad, while dependent claims use enumerated lists. Courts often require close mapping.

These issues affect both litigation leverage and the practical “clearance” work for generic formulators.

How many distinct claim scopes exist within US 5,759,580?

Based on the provided claims, there are effectively four enforceable scope “clusters”:

Nebivolol micronized tablet composition (Claim 1, plus tablet in Claim 2/7)
Micronization threshold via specific surface area (Claim 4/10)
Formulation quantitative constraints:
- API loading 1–4% (Claim 5)
- wetting ratio ranges, including Polysorbate ratio (Claims 6, 18–20)
Tablet performance (Claim 9 dissolution)

This structure matters because an accused product can be partially mapped but still fall outside at least one cluster, changing infringement probability and settlement dynamics.

What does the claim set indicate about the broader US nebivolol patent landscape?

Even without a full citation list of other patents, the claim set indicates the competitive battlefield in the US for nebivolol generics and formulations:

Particle engineering patents anchored to surface-area thresholds
Excipients and wetting system patents with quantified ratios
Tablet performance patents, particularly dissolution windows

In practice, this means market entrants often face multiple patents on:

micronization and/or crystallinity,
formulation excipient systems,
and dissolution/manufacturing method.

Without access to the complete US prosecution history and the Orange Book listing for the relevant nebivolol NDA(s), a complete “how many patents exist” count cannot be responsibly produced.

Key Takeaways

US 5,759,580 protects a micronized nebivolol oral solid formulation tied to specific surface area (≥23×10³ cm²/g) in dependent claims.
The formulation also has quantified excipient constraints, especially wetting agent (Polysorbate or sodium dioctylsulfosuccinate) with w/w ratio 0.025–0.5.
Additional dependent coverage can hinge on nebivolol hydrochloride loading (1–4%) and tablet dissolution (75% after 45 minutes).
For generic clearance and Paragraph IV risk assessment, the most direct technical comparisons are:
- measured surface area versus the claimed threshold,
- wetting-agent ratio versus the claimed ranges,
- API percent in the tablet,
- dissolution at the claimed timepoint.

FAQs

1) Does US 5,759,580 require Polysorbate specifically?
No. Claim 1 requires a wetting agent generally; Polysorbate is explicitly required in Claim 6, while Claims 15 and dependent ratio claims also cover sodium dioctylsulfosuccinate depending on dependency.

2) Can a generic avoid infringement by using a different filler or disintegrant?
Changing excipients alone may not avoid Claim 1 because it requires the carrier to include filler, lubricant, disintegrant, binder, and wetting agent. Dependent claim coverage can still depend on the ratio and micronization metrics.

3) Is the specific surface area requirement part of Claim 1?
No. The ≥23×10³ cm²/g threshold appears in dependent claims (Claim 4/10) in the provided text.

4) What test determines whether a product meets Claim 9 dissolution?
The claim requires 75% dissolution after 45 minutes. The precise test method used in litigation will control outcome, but the numeric performance target is explicit.

5) What single formulation change most directly addresses the tightest dependent claims?
The highest-leverage changes are typically (i) moving the measured micronized API surface area below 23×10³ cm²/g and/or (ii) moving the wetting-agent-to-API w/w ratio outside 0.025–0.5 (and likely outside sub-ranges).

References (APA)

United States Patent 5,759,580. (Claims as provided in prompt).

PCT Information
PCT Filed	February 10, 1995	PCT Application Number:	PCT/EP95/00489
PCT Publication Date:	August 24, 1995	PCT Publication Number:	WO95/22325

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	212547	⤷ Start Trial
Australia	1706895	⤷ Start Trial
Australia	688860	⤷ Start Trial
Brazil	9506828	⤷ Start Trial
Canada	2182582	⤷ Start Trial
China	1112921	⤷ Start Trial
China	1140991	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,759,580

Summary for Patent: 5,759,580