Details for Patent: 6,821,975

US Patent 6,821,975: Scope, Claims, and US Patent Landscape (Particle-Size-Controlled “Free Drug” Solid Forms)

United States Patent 6,821,975 claims a free (non-salt/non-prodrug) drug particulate solid with a defined particle-size distribution and then chains that particulate into (i) a solid pharmaceutical composition and (ii) methods of treating sexual dysfunction via administration of the solid composition. The patent’s enforceable core is the 90% passing thresholds (and related d90 language) that define particle size, not a specific device, dosing regimen, or manufacturing crystallization scheme beyond comminution of a solid free form.

What exactly is claimed? (Claim-by-claim scope and coverage)

Claim 1: baseline particulate size threshold for a “free drug particulate form”

Claim 1 covers:

• A free drug particulate form of a compound having:
  • a specified formula, or
  • pharmaceutically acceptable salts and solvates “thereof”
• Particles of the compound where:
  • at least 90% of particles have particle size < about 40 microns

Scope mechanics:

• The operative limitations are:
  1. “free drug particulate form” (free base/free acid concept, as opposed to salt forms as the “particle” being administered)
  2. ≥90% under a particle size cutoff of ~40 µm
• The claim is drafted as an inclusion around the compound “having a formula,” but it explicitly references pharmaceutically acceptable salts/solvates in the preamble. That language can be used to argue breadth on the compound identity category, while the term “free drug particulate form” narrows the physical form of the administered particles.

Practical infringement profile:

• If a competitor’s solid dosage contains particles such that 90% (by the patent’s measurement method) pass <40 µm, claim 1 is structurally in range.

Claims 2–4: narrower particle-size cutoffs

These claims tighten the particle-size threshold while keeping the same “free drug particulate form” and “≥90%” framework.

• Claim 2: ≥90% of particles < ~25 µm
• Claim 3: ≥90% of particles < ~15 µm
• Claim 4: ≥90% of particles < ~10 µm

Scope mechanics:

• These are narrower than claim 1.
• In enforcement, these claims create a ladder: if a formulation misses the tightest cutoff but meets the next one, it can still map to a broader claim.

Infringement sensitivity:

• The cutoff is “about” sized (for example, “about 40 microns”), creating allowance. Still, competitors typically test with laser diffraction or equivalent particle-sizing methods and can be measured against the “% passing” metric.

Claim 5: composition claim using the particulate

Claim 5 covers:

• A pharmaceutical solid composition comprising:
  • the free drug particulate form of claims 1–4
  • plus one or more pharmaceutically acceptable carriers, diluents, or excipients

Scope mechanics:

• This is a standard dosage-form bridge: it does not require any particular excipient type (beyond acceptability), any disintegrant, binder, or tableting method.
• The claim’s novelty and infringement hook remain the particle-size profile from claims 1–4.

Claims 6–8: method of treating sexual dysfunction

Claim 6 is a treatment method:

• A method of treating sexual dysfunction in a patient in need thereof
• administering a therapeutically effective amount of a solid composition comprising:
  • the free drug particulate form of claims 1–4
  • plus pharmaceutically acceptable carriers/diluents/excipients

Claim 7: sexual dysfunction is male erectile dysfunction
Claim 8: sexual dysfunction is female sexual arousal disorder

Scope mechanics:

• These are use claims with an administration of the claimed solid composition.
• They do not specify dosing frequency, treatment duration, patient characteristics, or concomitant therapies. The scope is anchored to:
  • patient need,
  • therapeutically effective amount,
  • and the claimed particle-size-controlled solid composition.

Design-around implications:

• If a competitor uses a different particle-size distribution outside the “≥90% <40/25/15/10 µm” range, it can evade the core claim set.
• If the competitor uses a different physical form (for example, salt particles rather than “free drug particulate form”), that can also be a path, subject to how “free drug particulate form” is construed.

Claims 9–10: manufacturing method using comminution

Claim 9 covers:

• A method of manufacturing the free drug particulate form of claim 1 comprising:
  • (a) providing a solid, free form of the compound
  • (b) comminuting the solid free form to provide particles where:
  • ≥90% have particle size < about 40 µm

Claim 10 adds:

• further step of:
  • admixing the comminuted particles with one or more pharmaceutically acceptable carriers/diluents/excipients

Scope mechanics:

• Claim 9 is not a crystallization process claim. It is a particle-size conversion claim by comminution.
• It does not claim milling equipment type, milling media, time, temperature, or resulting polymorph/crystal form stability. Those issues may still appear in the specification, but the claim language is narrow to the steps above.

Claim 11: composition claim keyed to d90

Claim 11 covers:

• a pharmaceutical solid composition prepared by admixing:
  • particles of a compound (formula or pharmaceutically acceptable salt/solvate thereof)
  • with carriers/diluents/excipients,
• where:
  • particles have d90 = 40 or less

Scope mechanics and potential alignment with claim 1:

• Claim 1 is expressed as “at least 90% of the particles have particle size < about 40 microns.”
• Claim 11 expresses a d90 metric:
  • d90 ≤ 40 µm
• These are typically interpreted as aligned:
  • d90 represents the particle diameter below which 90% of the distribution lies (under standard definitions).
• Claim 11 broadens the expression of the particle-size constraint, and it also uses “particles of a compound having a formula or a pharmaceutically acceptable salt or solvate thereof,” which can introduce ambiguity relative to the “free drug particulate form” terminology in claims 1–4. In enforcement, the claim’s particle-size and composition architecture matter most.

Design-around implication:

• A competitor can attempt to position distribution where d90 > 40 µm or where the %<40 µm condition is not met.

What is the patent’s technical “spine”? (The enforceable differentiator)

The patent’s claims repeatedly converge on one constraint:

• Particle size distribution controlled to a 90% passing threshold
  • < ~40 µm (claims 1, 9)
  • < ~25 µm (claim 2)
  • < ~15 µm (claim 3)
  • < ~10 µm (claim 4)
  • and d90 ≤ 40 µm (claim 11)

Everything else is a layer:

• form: free drug particulate form (claims 1–4)
• dosage architecture: solid composition with excipients (claim 5, 11)
• therapeutic use: sexual dysfunction including male erectile dysfunction and female sexual arousal disorder (claims 6–8)
• manufacturing: comminuting a solid free form (claim 9) and optionally admixing (claim 10)

Scope boundaries and claim interpretation pressure points

1) “Free drug particulate form”

This phrase is the key physical-form limiter for claims 1–4 (and linked into claim 5). If the marketed product uses:

• salt particles rather than free form particles, or
• a mixture where the “particle” being measured is salt-dominant,

then infringement becomes contestable based on construction and measurement practice.

2) Particle-size measurement and the “about” qualifier

All particle cutoffs are “about” in multiple claims. This increases litigation friction for exact numeric comparisons but still sets a clear target:

• a competitor’s distribution must miss the tested metric to avoid mapping.

3) “At least 90%” vs “d90=40 or less”

Claim 1 and claim 11 are likely measurement-equivalent in typical particle-dimension practice, but:

• claim 1 is expressed as a % below cutoff,
• claim 11 is expressed as d90, which depends on how the distribution is generated and reported.

Competitors often exploit measurement methodology differences to create a non-infringing profile if the metric is not met under the asserted method.

Patent landscape analysis: how other US patents typically intersect this claim set

Without identifying the compound name(s) covered by 6,821,975, a complete landscaping across US assignees, priority families, and citation networks cannot be produced with accuracy. The claim text you provided does not supply the drug identity (the formula is referenced but not reproduced), which is necessary to map:

• the compound-specific patent family,
• prior art compositions,
• co-crystal/salt form portfolios,
• and later particle-size or micronized form filings.

That said, the claims’ structure predicts where the US landscape tends to cluster for such particle-size-controlled free forms used in sexual dysfunction indications:

Expected adjacent patent categories that commonly overlap or litigate around this type of claim

1. Micronized solids / particle-size-controlled formulations
   • patents that claim lower d50, d90, or “%<X µm” for improved dissolution or bioavailability.
2. Salt form and polymorph portfolios
   • filings that claim alternative crystalline forms where particle size control may be applied, but the “free drug particulate form” limitation is avoided by using salts.
3. Drug product formulations for erectile dysfunction / sexual arousal disorders
   • use claims or composition claims where the active is known, and the novelty is often the physical form and particle size.
4. Manufacturing process patents for particle reduction
   • milling/comminution methods with measured distributions as outcomes.
5. Measurement-method-dependent claims
   • later filings that define d90 or specify the instrument/method (laser diffraction, sieving, microscopy) and can be used to argue non-equivalence.

Where 6,821,975 is most likely to land relative to that landscape

Based on the claim set, 6,821,975 is positioned as:

• a formulation physical-property patent (particle distribution),
• combined with compound “free form” restriction, and
• extended into sexual dysfunction therapeutic use.

In US enforcement, such patents often face:

• obviousness attacks over prior micronization and particle-size distribution disclosures,
• disputes over whether the marketed product uses a “free drug particulate form,” and
• metric disputes around d90 or 90% passing thresholds.

Operational risk map: how competitors typically read these claims

Direct hit paths

A competitor’s US product is at high risk if it uses:

• free form (not salt-dominant) particles, and
• particle distribution meeting ≥90% <40 µm,
• in a solid dosage form administered for sexual dysfunction.

Partial hit paths (claim ladder effects)

• If distribution meets ≥90% <40 µm but not the tighter thresholds, claim 1/5/6/9/11 are in play.
• If it meets tighter thresholds (<25, <15, <10 µm), more dependent claim coverage becomes available.

Design-around levers suggested by claim language

• Increase d90 above 40 µm (or fail “%<40 µm” under asserted method).
• Use a salt or solvate particle form as the administered solid (to avoid “free drug particulate form” limitations in claims 1–4, depending on construction).
• Use a manufacturing route that does not “comminute” a solid free form into the specified particle distribution, if process claims are asserted.

Key takeaways

• US 6,821,975 is a particle-size distribution patent: it requires ≥90% of particles below defined micron thresholds, with a d90 ≤ 40 µm variant.
• The patent’s enforceable spine spans:
  • free drug particulate form (claims 1–4),
  • solid pharmaceutical compositions (claims 5, 11),
  • sexual dysfunction therapeutic methods (claims 6–8),
  • and comminution manufacturing (claims 9–10).
• The most actionable infringement question is whether the commercial solid uses a free form particle distribution that meets the 90% passing or d90 ≤ 40 µm constraint under the relevant measurement practice.
• The broad US landscape around this kind of patent usually clusters into micronized solids, salt/polymorph portfolios, and particle-size-defined manufacturing filings; this patent adds the “free drug” form restriction and applies the particle distribution into a sexual dysfunction use frame.

FAQs

1) What is the most important numerical limitation in US 6,821,975?

The numerical trigger is “at least 90% of the particles” being below a specified micron cutoff. The baseline cutoff is about 40 µm, with dependent cutoffs at about 25, 15, and 10 µm, and claim 11 using d90 ≤ 40 µm.

2) Does the patent claim a specific dosage form type (tablet vs capsule vs powder sachet)?

No. Claims 5 and 11 cover a solid pharmaceutical composition with carriers/diluents/excipients. They do not require a particular solid unit operation or dosage form geometry.

3) Are the sexual dysfunction claims limited to a specific dosing regimen?

No. Claims 6–8 require administration of a therapeutically effective amount but do not specify dose amount, frequency, or treatment duration.

4) Is the manufacturing claim limited to milling equipment or conditions?

No. Claim 9 is limited to steps of providing a solid free form and comminuting it to achieve ≥90% < about 40 µm. No equipment, media, or parameter constraints are recited in the claim text provided.

5) What is the strongest likely design-around based on the claim language?

The clearest lever is to ensure the marketed product’s particle distribution does not meet the asserted 90% passing or d90 thresholds and to avoid using a free drug particulate form if salt/solvate particles are used as the administered solid form (subject to claim construction).

References

[1] US Patent 6,821,975, “Free drug particulate form with defined particle size distribution; pharmaceutical compositions; methods of treating sexual dysfunction.” (Claims as provided in prompt).