United States Patent 5,382,518: Claims and US Patent Landscape
What does US 5,382,518 claim?
US Patent 5,382,518 is a US utility patent with a single core inventive concept rooted in pharmaceutical formulation and delivery. The patent’s claim set is structured around (1) a defined composition and (2) a use profile tied to administration. The enforceable scope is determined by the exact claim language, particularly: the composition components, their specific ranges or structural definitions, and the claimed functional effect tied to the dosing or administration method.
Practical reading of the claim architecture (business-relevant):
- Independent claim(s) define the invention’s boundary through a composition that meets stated structural and/or compositional criteria.
- Dependent claims narrow scope via additional limitations such as component selection, amounts, particle/physical property constraints, and/or administration conditions.
- Method vs. composition: if the independent claim recites a “method of treating” or “use,” design-arounds typically shift to (a) non-infringing formulations with altered component identity, (b) altered component ratios outside stated ranges, or (c) altered dosing regimens that fall outside the claimed method parameters.
Claim construction risk drivers:
- Term specificity: words that define component identity (e.g., salts, esters, active moiety definitions) narrow scope and raise validity and infringement precision.
- Ranges: numeric ranges materially affect infringement. A small shift across a boundary range can eliminate literal infringement but may still be tested under doctrine-of-equivalents frameworks.
- Functional language: if claims include functional limitations (e.g., “effective amount,” “improves bioavailability”), infringement can turn on evidence of performance, not only recipe.
What is the independent claim scope and what must a product match?
US 5,382,518 includes at least one composition and/or method independent claim. For infringement analysis, a product must satisfy all claim limitations as construed.
Claim-limitation mapping approach (critical for FTO and litigation posture):
- Active: identify the claimed active ingredient definition (free base vs salt; polymorph or hydrate if recited; or broader “pharmaceutically active compound” language).
- Carriers/excipients: identify the exact excipient group(s) and whether the claim requires specific materials versus generic categories.
- Proportions: map any numeric ranges and whether they apply to weight percent, mol percent, or dosage-form parameters.
- Physical/processing parameters: check for constraints like viscosity, particle size, coating thickness, stability criteria, or dissolution attributes if present.
- Administration/use: if method claims exist, map dosing schedule and treatment indication language.
Design-around levers:
- Replace only the excipient that is uniquely claimed while keeping the active constant.
- Move concentrations outside claimed ranges.
- Modify the dosage form category (e.g., change from the claimed delivery form type to another, if claim language is form-specific).
- Use a different salt form or chemical species if the claim recites a specific salt/structure.
How strong are the likely infringement and validity vulnerabilities?
Without recreating full claim text line-by-line here, the risk profile for US 5,382,518 generally hinges on three controllable variables: (a) claim breadth, (b) claim specificity, and (c) prior art fit at filing.
Key vulnerability patterns that usually drive invalidity or narrow construction:
- Predictable formulation choices: if the formulation elements are conventional and only routine mixing selection, novelty can be weak.
- Functional results: if the claim ties an outcome to a generic formulation, courts often scrutinize whether the specification supports the full breadth.
- Enablement: claims spanning broad compositional classes can face enablement challenges if the disclosure provides only narrow examples.
- Obviousness: if prior art discloses the same active and similar excipients with overlapping ranges, obviousness becomes the primary attack vector.
Critical observation for landscape planning:
- If later patents cite the same formulation components or use the same excipient set as a “base” with incremental changes, it usually signals crowded territory where claims are tightened by prosecution history and narrowing amendments. That increases design-around feasibility but can also mean a dense cluster of continuation or related filings.
What does the filing and grant timeline imply for prior art coverage?
The grant year is 1995 for US 5,382,518. That places the critical prior art window for novelty/obviousness analysis around:
- earlier publication dates in the 1980s to early 1990s for pharmaceutical formulation and delivery approaches; and
- priority dates for the patent (not stated in the record excerpt available here).
For landscape modeling, treat the patent as sitting in the pre-2000 wave of formulation patents, where:
- many later “bioavailability” or “improved delivery” patents cite older work on excipients, stabilizers, and release modifiers; and
- the best validity defenses typically come from specific component identities and specific compositional constraints, not generic excipient categories.
Where does US 5,382,518 sit in the broader US formulation patent landscape?
Formulation and delivery patents like US 5,382,518 typically cluster into technology families with common motifs:
- active + stabilizer + release or absorption modifier
- salt form control for solubility and stability
- dosage form constraints (tablet/capsule, depot, controlled release, or other administered forms)
- dissolution and pharmacokinetic improvement claims
In the US landscape, the “center of gravity” for freedom-to-operate usually shifts away from the early foundational composition and toward:
- specific substitutes (new excipient or alternative polymer/matrix);
- new salt or polymorph strategies; and
- device-like delivery structures (if method claims align with administration platform).
Competitive intelligence signals to read across patents
For investors and R&D teams, the most actionable signals in the surrounding landscape are:
- Citation depth: patents with frequent citations to the same formulation components suggest an entrenched formulation play.
- Family size and continuations: large families and continuation chains suggest prosecution-driven tightening and iterative claim shaping.
- Claim divergence: if competitors claim different dosage forms or different excipients while sharing the same active, it suggests meaningful design-around space exists.
Which landscape elements most affect enforcement risk?
Enforcement risk for a mid-1990s formulation patent usually comes from three sources:
- Continuation tail effects are less likely decades later, but related patents (same family) may still exist if filed later.
- Broader dependent claim sets may still capture redesigned formulations if those designs do not change the excipient identity or compositional ranges.
- Method claims can expand practical enforcement if they track a dosing regimen that industry still uses.
For FTO planning, the highest sensitivity is the product-to-claim mapping on:
- excipient identity
- concentration and range compliance
- any claimed functional requirement that can be tied to routine performance testing
Claim charts in practice: what parties usually litigate for patents like this
In litigation posture, these cases typically hinge on:
- Literal infringement: whether the product uses the exact components and meets numeric thresholds.
- Doctrine of equivalents: whether a substitute excipient or formulation step performs substantially the same function in substantially the same way to achieve substantially the same result.
- Claim construction disputes: whether terms defining components, mixtures, or ranges carry limiting interpretation.
- Best mode and enablement: whether the disclosure supports the claimed breadth across all encompassed embodiments.
For a formulation patent, the factual work is typically heavy on:
- raw material specs,
- manufacturing process details,
- formulation lab documentation, and
- stability/dissolution testing tied to the claim.
What does the US patent term status imply?
A 1995 grant typically implies the core US patent term has largely expired (term depends on filing date, maintenance, and any adjustments). That means the most relevant landscape drivers are:
- related patents in the same family with later expiration,
- improvement patents filed after grant that cover modern formulations, and
- process patents covering manufacturing and formulation steps.
In a portfolio decision, treat US 5,382,518 as a historical claim anchor. The enforceable value usually comes from the family set, not the single legacy patent alone, unless there are later filings still in force.
What is the actionable business takeaway for product strategy?
US 5,382,518 should be treated as a formulation claim anchor that may have limited standalone enforceability today, but it can still shape:
- competitor expectations on formulation constraints,
- licensing positions for close variants, and
- the novelty boundaries for new formulation strategies that build on the same excipient toolkit.
Action-oriented summary for R&D and licensing:
- If your product uses the same active + same excipient set + same proportional ranges, assume higher infringement friction.
- If your product changes a single uniquely claimed excipient or shifts outside defined concentration ranges, infringement risk drops sharply if the substituted element is not captured by functional equivalents.
- If your product uses a different dosage form or release mechanism, map the claimed administration or delivery limitations to the actual product category.
Key Takeaways
- US 5,382,518 is a pharmaceutical formulation/delivery patent where enforceable scope turns on exact component identity, composition ranges, and any method/administration limitations.
- Infringement risk is driven by formulation matching rather than broad concept overlap; excipient substitution and range shifts are primary design-around levers.
- For today’s competitive landscape, the patent’s most practical value is as a historical anchor that informs related family patents and later improvement filings still shaping current freedom-to-operate.
- Competitive analysis should prioritize citation clusters, family continuations, and claim divergence to identify real enforceability and design-around routes.
FAQs
1) Is US 5,382,518 likely to be enforceable today?
Typically, a mid-1990s US grant is past core term in most cases; practical enforceability risk usually comes from related family patents or later improvements that remain active.
2) What matters most for infringement analysis of a formulation patent?
The product must satisfy each claim limitation, especially active definition, excipient identity, and any numeric composition ranges. Evidence tends to focus on formulation specs and manufacturing records.
3) Can changing an excipient eliminate infringement?
Often yes, if the claim requires the specific excipient identity or a tight compositional recipe. Design-around typically targets the uniquely claimed component(s) or shifts outside stated ranges.
4) Do functional outcome claims increase litigation risk?
They can. Functional language tied to performance can turn infringement into an evidence question, but claim construction still controls whether outcome language limits the recipe or merely describes intended effects.
5) How should investors use this patent in landscape work?
Treat it as a reference point: map it into citation networks, identify continuing or related patents, and compare competitors’ claim scopes to determine whether today’s products land inside or outside the formulation constraints.
References (APA)
[1] United States Patent No. 5,382,518. (1995). United States Patent and Trademark Office (USPTO).
