United States Patent 6,060,085: What Is Claimed, How Broad It Is, and Where It Sits in the US Dermatology Delivery Landscape
What does US 6,060,085 claim?
US 6,060,085 claims topical treatment methods and related gel-composition preparation methods built around dual-state drug delivery in one aqueous semisolid gel:
- a first pharmaceutical that exists in two forms in the same gel: (i) dissolved and (ii) microparticulate, where the dissolved portion targets early-stage lesions and the microparticulate portion targets later-stage lesions; and
- a second pharmaceutical that is dissolved and delivers benefit throughout lesion progression.
The claims also extend to systemic vs local penetration behavior and to acne-specific targeting in the pilosebaceous unit.
Core independent claim (Claim 1): dual-state + lesion-stage timing
Claim 1 is the anchor for scope. It requires all of the following:
- Method for dermatological conditions
- Topical application of a semisolid gel composition
- Gel composition must include:
- semisolid aqueous gel
- first pharmaceutical: “partially in a microparticulate form and partially dissolved”
- second pharmaceutical: dissolved
- Functional delivery logic tied to lesion stage:
- first pharmaceutical:
- optimized delivery for early stage lesions when dissolved
- optimized delivery for later stage lesions when present as a microparticulate
- second pharmaceutical:
- benefit throughout lesion progression
This claim is not limited to any single active ingredient, but it is limited to the structure of the formulation and the functional partitioning of delivery across lesion progression.
Dependent claims: the active ingredient scope
The dependent claims narrow Claim 1 through defined active ingredient lists and specific embodiment selections.
Claim 2 (both first and second pharmaceuticals are from enumerated classes):
- antimicrobial agent
- anti-inflammatory agent
- antiviral agent
- local anesthetic agent
- corticosteroid
- destructive therapy agent
- antifungal agent
- antiandrogen agent
This list is broad in therapeutic category but narrow in the sense that each drug must fall within one of those functional classes.
Claims 3-5 (dapsone-specific):
- Claim 3: first pharmaceutical is dapsone
- Claim 4: second pharmaceutical is dapsone
- Claim 5: first pharmaceutical is dapsone and second pharmaceutical is dapsone
These three claims establish strong species-level coverage for dapsone dual-drug-state topical gels.
What is the “systemic vs local penetration” claim scope?
What does Claim 6 add beyond Claim 1?
Claim 6 shifts the delivery narrative from lesion progression to penetration behavior:
- A method of treating disease by topically applying an aqueous gel containing:
- a dissolved pharmaceutical and a microparticulate pharmaceutical
- Functional penetration requirement:
- dissolved pharmaceutical crosses stratum corneum to become systemically available
- microparticulate pharmaceutical minimally crosses stratum corneum in its microparticulate state
So Claim 6 can be viewed as a penetration-profile version of the dual-state concept, with different endpoints (systemic availability vs minimal crossing).
Claim 6 is not, on its face, tied to lesion-stage timing the way Claim 1 is. It is tied to relative penetration by form.
Dose-range language in Claim 7 and Claim 8
- Claim 7: antiviral agent at 1.0% to 10% (w/w)
- Claim 8: antiandrogen at 0.5% to 10% (w/w)
These are typical composition-range limiters that can matter for design-around and for infringement analysis depending on how “includes between about” is interpreted in enforcement.
Acne-specific penetration and pilosebaceous targeting
What does Claim 9 require?
Claim 9 is narrower by disease indication and tissue compartment targeting:
- Method for treating acne by topical application of a gel composition comprising:
- dissolved anti-inflammatory pharmaceutical
- microparticulate antimicrobial pharmaceutical
- Penetration partitioning:
- dissolved anti-inflammatory:
- crosses stratum corneum
- is absorbed into the lower two-thirds of the pilosebaceous unit
- microparticulate antimicrobial:
- primarily delivered into the upper third of the pilosebaceous unit
- crosses stratum corneum only minimally
This claim is built around microanatomical distribution (upper vs lower thirds of the pilosebaceous unit) and dual function pairing (anti-inflammatory in dissolved form, antimicrobial in microparticulate form).
Claim 10 then specifies a dapsone embodiment:
- dissolved anti-inflammatory pharmaceutical is dapsone
- microparticulate antimicrobial pharmaceutical is dapsone
This is a second species-specific dapsone claim outside Claim 1.
Manufacturing-process claims: gel preparation with specific solvent classes
What is claimed in Claim 11 and Claim 14?
Claims 11 and 14 protect process steps to make the gel with both dissolved and microparticulate drug states.
Claim 11: three-step dispersion build with caustic gel formation
Claim 11 includes:
- Dissolve methylparaben and propylparaben in a solvent to form a solution
- Dissolve a pharmaceutical into that solution (pharmaceutical component)
- Contact water and a polymer to form a homogeneous dispersion
- Contact the pharmaceutical component and homogeneous dispersion to form a pharmaceutical dispersion
- Contact the pharmaceutical dispersion and a caustic material to form a dermatological gel composition
Critical material limits:
- solvent is ethoxydiglycol or 1-methyl-2-pyrrolidone
- the gel comprises dissolved pharmaceutical and microparticulate pharmaceutical
Claim 12: species examples for the pharmaceutical
- pharmaceutical is acyclovir, tetracaine, tetracaine hydrochloride, or combination
Claim 13: pharmaceutical is dapsone
Claim 14: two dispersion contacts then caustic gel formation
Claim 14 differs in intermediate structure:
- Dissolve methylparaben and propylparaben in a solvent
- Dissolve pharmaceutical to form pharmaceutical component
- Contact water and pharmaceutical component to form a first pharmaceutical dispersion
- Contact first pharmaceutical dispersion and a polymer to form a second pharmaceutical dispersion
- Contact second pharmaceutical dispersion and a caustic material to form the gel
Again:
- solvent is ethoxydiglycol or 1-methyl-2-pyrrolidone
- gel comprises dissolved pharmaceutical and microparticulate pharmaceutical
Claim 15: pharmaceutical is acyclovir, tetracaine, tetracaine hydrochloride, or combination
Claim 16: pharmaceutical is dapsone
Scope analysis: how broad are these claims in practice?
1) Broad concept coverage, narrow formulation architecture
The invention concept is broad at the “delivery-state + dual role” level:
- “dissolved” vs “microparticulate” within the same semisolid aqueous gel
- functional delivery behavior (early vs later lesions; systemic vs minimal stratum corneum crossing; upper vs lower pilosebaceous unit targeting)
But it is narrow at the enforceable architecture level:
- same topical gel composition must contain both states for at least the first pharmaceutical in Claim 1
- microparticulate must be present in a defined spatial and functional sense
- aqueous semisolid gel is required in Claim 1 (and aqueous gel in Claim 6)
2) Active-ingredient breadth is medium, with dapsone as a protected core
- Claim 2 provides class-level breadth via functional drug categories, not chemistry.
- Claims 3-5, 10, 13, and 16 make dapsone a high-value species within the portfolio.
- That creates a typical enforcement center of gravity: products using dapsone in dual-state form face the tightest risk.
3) Indication breadth is constrained to dermatological use cases
Even though the claims use “dermatological conditions” and “treating disease,” certain claims lock in:
- acne (Claim 9-10)
- lesion progression language (Claim 1)
In many enforcement contexts, disease-specific claims can reduce ambiguity, while generic dermatological language increases the pool of potential accused products.
Claim-by-claim infringement levers (what defendants must avoid)
A. Avoid having both dissolved and microparticulate drug states in the same gel
- For Claim 1, the first pharmaceutical must be partially microparticulate and partially dissolved.
- Moving to either:
- fully dissolved, or
- fully microparticulate,
- or delivering states in separate dosage forms (separate products or separate compartments)
can defeat elements depending on how strictly “within said semisolid aqueous gel” is enforced.
B. Avoid matching the functional delivery mapping
Even if formulation is similar, functional requirements can matter:
- early lesions when dissolved vs later lesions when microparticulate (Claim 1)
- systemic availability vs minimal stratum corneum crossing by form (Claim 6)
- upper vs lower pilosebaceous unit partitioning (Claim 9)
In litigation, functional mapping is often where parties fight over evidence, but the claim elements still create a necessary correspondence.
C. Avoid dapsone dual-state embodiments
Multiple claims specifically name dapsone:
- Claim 3-5 (dapsone as first and/or second)
- Claim 10 (dapsone as both dissolved anti-inflammatory and microparticulate antimicrobial in acne)
- Claim 13 and Claim 16 (dapsone in process claims)
A product with dapsone in a conventional topical gel format may still be assessed against process claims if a patented process was used, and against method claims if microparticulate fractions and delivery behavior match.
D. For process claims, avoid the specific manufacturing pathway
Claims 11 and 14 share structure:
- paraben dissolution in a defined solvent (ethoxydiglycol or 1-methyl-2-pyrrolidone)
- pharmaceutical component formation
- water + polymer contact to form a dispersion
- caustic material contact to form the gel
- end state must include dissolved + microparticulate pharmaceutical
A different solvent system, different gel base formation route, or different dispersion formation sequence can move outside the claims if elements are not met.
Patent landscape positioning (US)
How US 6,060,085 typically nests in a dermatology delivery patent portfolio
Within US dermatology and topical delivery portfolios, claims like these sit at the intersection of:
- formulation architecture patents (dual-state in a single gel)
- tissue penetration and distribution patents (stratum corneum crossing, pilosebaceous unit distribution)
- active-ingredient species coverage (dapsone being the anchor)
- process patents (dispersion build and gel formation sequence)
Given the claim structure, the strongest landscape relevance is to products attempting to:
- combine anti-inflammatory and antimicrobial activity with differential localization, or
- create controlled release/penetration behavior by mixing dissolved and particulate drug fractions.
Where this claim set is “threatening” to competitors
From a freedom-to-operate perspective, US 6,060,085 is threatening when an accused product:
- uses dissolved + microparticulate drug states in the same topical aqueous gel, and
- uses drug pairing or delivery mapping similar to the claim logic (lesion progression, systemic vs minimal crossing, pilosebaceous compartment targeting), and
- is dapsone-based, or uses actives that match claim species in the process claims.
Where it may be easier to design around
Potential design-around pathways (conceptually) include:
- using only dissolved drug (no microparticulate fraction)
- using only particulate drug (no dissolved fraction)
- using separate formulations rather than “within said semisolid aqueous gel” carrying both states
- altering gel-forming steps and/or solvent choice away from ethoxydiglycol or 1-methyl-2-pyrrolidone in the process claims
These are practical levers because the claims explicitly require both the formulation state and the process state.
Key Takeaways
- US 6,060,085 is a dual-state topical delivery patent: it requires dissolved drug + microparticulate drug within a semisolid aqueous gel, with functional delivery mapping to lesion progression, penetration, or pilosebaceous compartment distribution.
- Dapsone is the central species across both method and process claims (multiple dependent claims lock it in).
- The portfolio also includes process protection with defined solvent classes (ethoxydiglycol or 1-methyl-2-pyrrolidone) and a caustic-driven gel formation step, tied to achieving a final gel containing both dissolved and microparticulate drug.
- Enforcement risk concentrates on competitors that replicate the same drug-state architecture and the same functional distribution logic, especially for dapsone-based acne/dermatological therapies.
FAQs
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Does Claim 1 require two different drugs (first and second pharmaceutical)?
Yes. Claim 1 requires a first pharmaceutical with partial microparticulate and partial dissolved presence, and a second pharmaceutical that is dissolved.
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Can the “first pharmaceutical” and “second pharmaceutical” be the same drug?
Yes. Claim 5 states both the first and second pharmaceutical are dapsone.
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What is the difference between Claim 1 and Claim 6?
Claim 1 maps delivery by lesion stage (early vs later) using dissolved vs microparticulate states. Claim 6 maps delivery by penetration outcome (systemic availability vs minimal stratum corneum crossing).
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Is the acne claim tied to specific tissue regions?
Yes. Claim 9 specifies distribution into the upper third vs the lower two-thirds of the pilosebaceous unit based on dissolved vs microparticulate forms.
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What is protected in the manufacturing claims?
Claims 11 and 14 protect a specific gel preparation sequence that uses defined solvent options and dispersion-building steps, resulting in a gel containing both dissolved and microparticulate drug.
References
[1] User-provided claim text for US Drug Patent 6,060,085 (claims 1-16).
