United States Patent 5,863,560 (Drug) — Scope, Claim Architecture, and US Patent Landscape
What does US 5,863,560 claim, in plain claim scope terms?
US Patent 5,863,560 is directed to semisolid aqueous dermatological gel compositions that contain the same API in two physical forms within the same gel matrix:
- a dissolved (systemically-available) fraction that can cross the stratum corneum and become systemically available, and
- a microparticulate (non-crossing) fraction that remains localized in microparticulate state and does not cross the stratum corneum.
The core invention is a dual-form formulation strategy for dermatologic or lesion treatment, combining:
- a gel base with a defined rheology system (notably carbomer, water, and ethoxydiglycol), and
- microparticulate/dispersed API particles plus dissolved API.
Claim-by-claim scope (independent and dependent)
Claim 1 (independent, compositional for dapsone gel)
A dermatological gel with:
- ~1% carbomer
- ~83.7 to 86.4% water
- ~10% ethoxydiglycol
- ~0.2% methylparaben
- up to ~3% dapsone in both microparticulate and dissolved states
- ~2% sodium hydroxide solution
This is a specific composition with tight excipient bands and a dapsone dual-state loading ceiling.
Claim 2 (dependent, microparticulate:dissolved constraint)
- Ratio of microparticulate to dissolved dapsone is no greater than 5.
This limits how much API is in the microparticulate fraction versus dissolved fraction. Read as a capsule distribution control: microparticles cannot dominate beyond a 5:1 upper ratio.
Claim 3 (independent, acyclovir dual-form herpes lesion gel)
A semisolid aqueous gel for herpes lesions comprising:
- acyclovir in both dissolved and microparticulate forms
- and 1-methyl-2-pyrrolidone (1-MP)
Claim 3 is broader in gel-base definition (only “semisolid aqueous gel” is required) but introduces 1-MP and limits the dual-form to acyclovir and the lesion indication to herpes lesions.
Claim 4 (independent, functional formulation scaffold; most important “platform” claim)
A dermatological composition comprising:
- a semisolid aqueous gel
- a dissolved pharmaceutical that can cross stratum corneum to become systemically available
- a microparticulate pharmaceutical dispersed in the gel that does not cross the stratum corneum in microparticulate state
- the dissolved and microparticulate fractions are the same pharmaceutical
Claim 4 captures the invention as a functional dual-form stratum corneum partitioning concept, not limited to one API or one excipient recipe.
Claim 5 (dependent from claim 4, dual-form nucleoside analogue + second dissolved local anesthetic)
A dermatological composition (herpes lesion treatment) comprising:
- semisolid aqueous gel
- first pharmaceutical: a nucleoside analogue, partly microparticulate and partly dissolved, selected from:
- acyclovir, penciclovir, famciclovir, valacyclovir, ganciclovir
- second pharmaceutical dissolved: local anesthetic selected from:
- tetracaine, tetracaine HCl, dyclonine, dyclonine HCl, dibucaine, dibucaine HCl
This claim expands from the functional dual-form scaffold into a combination gel with a lesion antiviral/analog in dual physical forms plus a distinct dissolved local anesthetic.
Claims 6-7 (dependent: % by weight exemplars)
- Claim 6: acyclovir ~5% by weight
- Claim 7: tetracaine HCl ~5% by weight
Claims 8-10 (dependent from claim 4, specific dapsone embodiments and ranges)
- Claim 8: dissolved and microparticulate pharmaceutical are dapsone
- Claim 9: includes about 0.5 to 10 wt% dapsone
- Claim 10: includes 0.5 to 10 wt% dapsone and 0.5 to 4 wt% carbomer
What is the “center of gravity” across the claim set?
- Claim 4 is the platform: “same drug in dissolved and microparticulate forms” with opposite stratum corneum-crossing behavior (systemic availability vs no crossing).
- Claims 1 and 8-10 anchor a dapsone gel embodiment with measurable excipient and concentration constraints.
- Claims 3 and 5-7 anchor herpes lesion gels using acyclovir (Claim 3) and nucleoside analogue + local anesthetic (Claim 5).
What does the scope likely cover for competitors? (Enforceability mapping to formulation design)
1) Dual physical-form requirement is the gating element
Any gel that does not contain:
- the same API in both dissolved and microparticulate states, and
- those states that yield the functional crossing partition described in Claim 4,
is less likely to fall within the central claim.
Even if a competitor uses microparticles for a topical sustained effect, Claim 4 creates exposure risk mainly when the formulation also provides a dissolved fraction capable of crossing while simultaneously maintaining a microparticulate fraction that does not cross “in microparticulate state.”
2) “Semisolid aqueous gel” still leaves broad design space
“Semisolid aqueous gel” in Claims 3-5 and 4 is not restricted to carbomer/ethoxydiglycol in those claims. That matters because competitors can attempt to move off the specific excipient recipe (Claim 1) and still test for Claim 4 coverage via functional dual-form behavior.
3) Excipients and concentrations matter most for Claims 1, 10, and exemplar dependent claims
- Claim 1 hard-codes:
- carbomer ~1%
- water 83.7-86.4%
- ethoxydiglycol ~10%
- methylparaben ~0.2%
- sodium hydroxide ~2% (neutralization/base adjuster)
- dapsone up to ~3% in dual form
- Claim 10 limits carbomer to 0.5-4 wt% (with dapsone 0.5-10 wt%).
- Claims 6-7 are specific “about 5%” exemplars.
If a competitor remains within functional Claim 4 but changes excipient system and concentration bands, their risk is primarily to Claim 4 (and Claim 4-derived dependent claims that track those parameters only when explicitly required).
4) Microparticulate:dissolved ratio constraint (Claim 2) can create a numerical design-around
For dapsone gels under Claim 1/related dapsone embodiments, Claim 2 requires:
- microparticulate:dissolved dapsone ≤ 5.
This does not eliminate dual-form gels; it restricts how dominant the microparticle fraction can be. A competitor could attempt to keep the microparticulate fraction below that threshold while still employing a particulate fraction.
How strong is the claim set as a patent landscape “blocking” tool?
Independent claims and their breadth
| Claim |
Independence |
API scope |
Key restriction style |
Likely practical breadth |
| 1 |
Independent |
Dapsone only |
Tight excipient percentages + dual-state loading |
Narrow compositional + specific gel recipe |
| 3 |
Independent |
Acyclovir only |
Requires 1-methyl-2-pyrrolidone + dual-state |
Moderate (API + cosolvent anchored) |
| 4 |
Independent |
Same pharmaceutical (any drug that fits functional behavior) |
Functional crossing partition + same API in both states |
Broad “platform” formulation |
| 5 |
Dependent on 4 |
Nucleoside analog list + local anesthetic list |
Combination + dual-form first drug + second drug dissolved |
Moderate (drug lists constrain but still wide) |
Platform implication
The broadest risk driver is Claim 4 because it is:
- not limited to dapsone or acyclovir,
- tied to a functional “systemic vs non-crossing” behavioral split between dissolved and microparticulate states,
- tied to the requirement that both fractions are the same pharmaceutical.
In an FTO or freedom-to-operate assessment, Claim 4 is the claim that typically forces competitors to prove:
- their formulation does not maintain the “microparticulate does not cross stratum corneum” functional partition, or
- their formulation does not have the required dissolved fraction capable of crossing, or
- their microparticulate fraction is not in the same API as the dissolved fraction, or
- their product is not within the “semisolid aqueous gel” category.
What does the claim language indicate about the formulation technology? (Technical reading of constraints)
Gel base (for Claim 1 and Claim 10)
The Claim 1 recipe suggests a gel with:
- carbomer as a polymer network (neutralized by sodium hydroxide)
- ethoxydiglycol as a penetration/cosolvent component
- methylparaben as preservative
- high water content as the continuous phase
Dual-state dapsone and dual-state acyclovir
The claims require:
- microparticulate fraction: dispersed solids (API particles)
- dissolved fraction: soluble API in gel medium
- ratio constraints for dapsone (Claim 2)
This is consistent with an engineering approach where a portion of API is kept soluble while a portion is maintained as particles to modulate local persistence and stratum corneum interaction.
1-methyl-2-pyrrolidone for acyclovir (Claim 3)
Claim 3 requires 1-MP. That narrows the design space for acyclovir formulations if they want to avoid Claim 3 while still potentially overlapping Claim 4.
Combination gel with local anesthetic (Claim 5)
Claim 5 adds:
- a lesion antiviral or analog in dual form
- a local anesthetic that is only dissolved (not specified in microparticulate form)
This implies a two-function gel: lesion antiviral delivery plus symptomatic relief through a dissolved anesthetic.
US patent landscape: what can be said from the claim set alone
The user-provided record includes only the claim text for US 5,863,560. A complete, accurate patent landscape requires bibliographic and citation data (file history, assignees, cited patents, forward citations, family members, legal status, continuation status). That data is not present in the input, so a full “landscape map” cannot be produced without risking incorrect statements about:
- which patents were cited by the examiner,
- which patents are active/expired in forward citation chains,
- whether there are continuation applications expanding the same subject matter,
- whether other families exist with similar dual-form microparticle/dissolved logic.
Accordingly, only the landscape conclusions that are derivable purely from the provided claim scope are stated: the technical and legal “center of gravity” and the likely design-around vectors.
Where are the likely design-around vectors based on the claim limits?
1) Avoid “same pharmaceutical” in dissolved and microparticulate states
If a competitor uses:
- dissolved API A for penetration and
- microparticles of a different API B for local effect,
it should fall outside the “same pharmaceutical” requirement in Claim 4.
2) Avoid the stratum corneum crossing functional pairing
Even if the same drug is in two forms, the formulation must produce:
- dissolved fraction that can cross and become systemically available, and
- microparticulate fraction that does not cross in microparticulate state.
A competitor that changes particle characteristics, surfactant systems, or partitioning so that microparticles can cross (or so dissolved fractions cannot cross) can reduce Claim 4 alignment.
3) For dapsone-specific embodiments: shift excipient bands or ratio
- Claim 1 is narrow via excipient percentages and up to ~3% dapsone.
- Claim 2 adds a numerical microparticulate:dissolved ratio cap (≤ 5).
Design around would typically target those numeric features for dapsone gels.
4) For acyclovir-specific embodiments: remove required co-solvent or avoid the acyclovir dual-form pairing under claim 3
Claim 3 requires 1-MP. If a competitor’s acyclovir gel omits 1-MP, it should not meet Claim 3 as written, though it could still be assessed against Claim 4.
5) For herpes lesion combinations: alter drug selection lists or dosing
Claim 5 is constrained by:
- nucleoside analogue list for the dual-form first pharmaceutical, and
- local anesthetic list for the second dissolved pharmaceutical.
Switching to anesthetics outside the list, or nucleoside analogs outside the list, can reduce dependent claim coverage.
Key Takeaways
- US 5,863,560 is centered on a dual-form gel strategy where the same API exists in both dissolved and microparticulate forms, yielding opposite stratum corneum crossing behavior.
- Claim 4 is the dominant platform claim: it is functional and potentially covers many APIs if they satisfy the “systemic via dissolved fraction” and “no crossing via microparticulate state” behaviors.
- Claim 1 is a narrow, dapsone-specific gel recipe with fixed excipient bands and an upper dapsone limit.
- Claim 2 adds a numerical ratio limit for dapsone dual-form distribution.
- Claim 3 and Claim 5 restrict scope through drug identity lists and (for claim 3) the required co-solvent 1-methyl-2-pyrrolidone.
- Without additional bibliographic/citation/legal-status data, a full US forward/backward citation landscape cannot be built from the provided input; risk analysis must be anchored to the claim platform structure and explicit constraints above.
FAQs
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Which claim is the broadest in US 5,863,560?
Claim 4, because it defines the invention functionally for a “semisolid aqueous gel” with dissolved and microparticulate fractions of the same pharmaceutical having opposite stratum corneum crossing behavior.
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Does the patent require both dissolved and microparticulate forms of the same drug?
Yes. Claim 4 explicitly requires the dissolved and microparticulate pharmaceuticals be the same pharmaceutical.
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What additional numerical limitation applies to dapsone formulations?
Claim 2 limits the microparticulate to dissolved dapsone ratio to no greater than 5.
-
What is the co-solvent requirement for acyclovir under this patent?
Claim 3 requires 1-methyl-2-pyrrolidone in the semisolid aqueous gel with acyclovir in dissolved and microparticulate forms.
-
What does Claim 5 add beyond the dual-form antiviral?
It adds a second dissolved local anesthetic selected from a defined list, while the nucleoside analogue is present partly microparticulate and partly dissolved.
References
[1] US Patent 5,863,560, claims 1-10 (provided claim text).
