US Patent 4,946,853 (Nicotine Controlled-Release Percutaneous Delivery): Claim Scope, Patent Estate Map, and Generic/Biosimilar Risk

US Patent 4,946,853 claims once-daily, percutaneous nicotine in a solid or semi-solid (or mucilaginous) medium that enables controlled skin release, with explicit coverage of formulation ingredients, device integration, and withdrawal/dependence treatment regimens tied to plasma nicotine targets.

The patent’s practical scope is split into three enforceable buckets: (i) composition-of-matter for controlled-release nicotine compositions, (ii) composition formats and manufacturing/design constraints (patch/plaster, surface area/thickness, priming dose structures), and (iii) method-of-treatment claims that use PK-equivalence to intermittent smoking and specific ng/mL plasma concentration windows.

What does US 4,946,853 claim for once-daily percutaneous nicotine?

Core independent claim coverage (composition + controlled release to skin). Claim 1 covers a topical nicotine preparation where:

Once-daily percutaneous administration
Nicotine is uniformly distributed in a solid or semi-solid medium
The medium is a solution of nicotine in a solidifying or gel-forming agent (or mixture) in a suitable solvent/solvent mixture, then mixed/heated to form the medium
The medium is effective for controlled release of nicotine to the skin

Key practical meaning: To infringe claim 1, an accused product must satisfy all of:

nicotine dispersed in a solid/semi-solid or mucilaginous matrix,
matrix formed from nicotine + gel/solidifying agent + solvent, processed by mixing/heating,
controlled release through skin contact, and
use as a once-daily percutaneous treatment.

How broad is the “solidifying or gel-forming agent” element?

Claim 6 drives breadth by listing “solidifying or gel-forming agent” categories and then narrowing via dependent claims. Claimed agent families include:

Plant extracts (claim 7: agar, ispaghula/psyllium, cydonia, ceratonia)
Hydrogenated castor oil (claim 8)
Gums (claim 9: guar, acacia, ghatti, karaya, tragacanth)
Polysaccharides (claim 10: alkylcelluloses, hydroxyalkylcelluloses, cellulose ethers/esters, nitrocelluloses, dextrin, agar, carrageenan, pectin, furcellaran, starch/starch derivatives)
Polypeptides (claim 11: zein, gelatin, collagen, polygeline)
Alginates (claim 12: alginic acid, propylene glycol alginate, sodium alginate)
Hydrocarbons (claim 13: soft paraffin, hard paraffin)
Carboxyvinyl polymer (claim 14)
Minerals (claim 15: bentonite, hectorite, aluminum magnesium silicate, magnesium silicate)
Silicon compounds (claim 16: colloidal silicon dioxide, silicones, polysiloxanes, silica gels)

Risk insight: Because claim 6 is framed as an agent “selected from” a large list and then enumerates numerous substitute types, many commercial nicotine matrices that rely on gels, polysaccharides, alginates, or waxy/hydrocarbon semisolids can sit within the literal footprint if they meet the other structural elements (once-daily, solvent processing, controlled skin release).

What solvents are explicitly covered?

Claim 2 limits (but does not excessively narrow) solvent selection to:

water, ethanol, stearyl alcohol, glycerol, ethylene glycol, propylene glycol, and silicone (or mixtures).

Form factor constraints: surface area and thickness

Claim 3 and claim 4 add physical dimensions:

Surface area: 2 to 15 cm² (claim 3)
Thickness: 0.5 to 3 mm (claim 4)

Enforcement impact: Many nicotine transdermal systems have different geometries and laminate thicknesses; however, a product within these numeric ranges is a direct claimant fit.

Dosage range coverage

Nicotine content: 5 to 100 mg (claim 17)
Preferred range dependent: 10 to 50 mg (claim 18)

Additive repertoire: almost every common topical excipient class

Claim 19 adds “one or more additional components” from categories including:

antimicrobial/preservative, antioxidant, pH-controlling agent, plasticizer, surfactant, penetration enhancer, humectant, local anesthetic, rubefacient.

Dependent claims list specific exemplars:

Preservatives/antimicrobials (claim 20) include benzalkonium chloride, CTAB, benzoic acid/esters, chlorhexidine, chlorobutanol, phenylmercuric acetate, borate/nitrate, potassium sorbate, sodium benzoate, sorbic acid, mercurithiosalicylate.
Antioxidants (claim 21): sodium metabisulphite, BHA, BHT.
pH adjusters (claim 22): citric acid, sodium citrate.
Plasticizers (claim 23): diethylphthalate, tributylcitrate.
Surfactants (claim 24): SLS, monostearates, PEGs, polysorbates, PVA.
Penetration enhancers (claim 25): DMSO, DMAC, DMF, 2-pyrrolidone, N-methyl-2-pyrrolidone, 1-dodecyl azacyclo-heptan-2-one.
Humectant (claim 26): glycerol.
Local anesthetics (claim 27): lidocaine, benzocaine, lignocaine, methocaine, butylaminobenzoate, procaine.
Rubefacients (claim 28): camphor, menthol.

Risk insight: This is a classic “matrix + excipient slots” claim. Many nicotine patches use humectants, tackifiers, surfactants, antioxidants, and preservatives. A product meeting the matrix and solvent/processing elements plus any combination of these components can remain within claim 19’s broader “one or more” structure.

How do patch, receptacle, and “priming dose” features expand infringement exposure?

Claim 29 and claim 30 anchor the composition into typical delivery mechanisms:

Received in a receptacle of a skin-contacting device (claim 29)
Incorporated in self-adhesive patch bandage or plaster (claim 30)

Priming dose structural limitations (two dependent claim variants)

Claims 31 and 32 require a priming dose of nicotine in specific adhesive layers that are permeable (claim 31) or positioned in a peripheral layer (claim 32):

Priming dose in a layer of adhesive defining the skin-contacting surface, freely permeable to nicotine (claim 31)
Priming dose in a peripheral layer of adhesive defining part of the skin-contacting surface (claim 32)

Risk insight: If competitors design multilayer adhesives with a distinct initial nicotine release “kick” layer, these dependent claims can be highly relevant even when the main matrix resembles the general claim 1 composition.

What methods of treatment are protected by US 4,946,853?

US 4,946,853 includes method claims built on PK-equivalence and plasma concentration thresholds.

Smoking cessation withdrawal symptoms (method claims 33–38)

Claim 33 covers:

Treat withdrawal symptoms associated with smoking cessation
Administer once-daily, percutaneous to a person in need
Dose nicotine sufficient to maintain plasma nicotine levels substantially equivalent to trough plasma levels from intermittent smoking
Nicotine distributed in solid/semi-solid/mucilaginous medium enabling controlled release to skin

Claims 34–37 add numeric PK triggers:

2 ng/mL within 1 hour (claim 34)
5 ng/mL within 1 hour (claim 35)
2 to 100 ng/mL over 1 to 24 hours (claim 36)
5 to 30 ng/mL over 1 to 24 hours (claim 37)

Claim 38 adds a taper:

Nicotine levels are progressively lowered over time, reducing dependence.

Psychological dependence via frequent smoking (method claims 39–43)

Claim 39 mirrors claim 33’s structure but targets psychological dependence:

Maintain plasma nicotine levels substantially equivalent to trough levels from intermittent smoking
Once-daily percutaneous delivery in controlled-release solid/semi-solid/mucilaginous medium.

Claims 40–43 repeat the numeric thresholds:

2 ng/mL within 1 hour (claim 40)
5 ng/mL within 1 hour (claim 41)
2 to 100 ng/mL over 1 to 24 hours (claim 42)
5 to 30 ng/mL over 1 to 24 hours (claim 43)

Enforcement impact: Method claims depend on actual administration and measured PK. For litigation, this tends to pull in:

label claims aligned with smoking cessation,
clinical PK data from product studies,
and potentially expert testimony comparing measured plasma-time profiles to the claimed windows.

How many patent families typically surround nicotine transdermal controlled-release compositions?

Without a dossier (filing date, priority, assignee, prosecution history, and citation graph), a full quantitative “how many patents” count cannot be produced accurately. What can be stated from claim scope alone is the landscape shape: transdermal nicotine systems typically cluster around:

controlled-release matrices (polysaccharides, waxes, alginates, hydrocolloids),
delivery device architectures (multilayer adhesives, permeable layers, receptacles),
dose release profiles (priming/initial spike vs steady-state), and
treatment regimens with PK-linked targets.

In that framework, US 4,946,853 is positioned as a formulation and method patent that tries to cover both the composition and the initial pharmacokinetic effect.

Which claim elements are most likely to be contested in infringement analyses?

1) “Once-daily” limitation

If an accused product is used differently (e.g., twice daily or variable dosing), defendants often attack the claim construction or evidence of label/instructions and real-world use.

2) “Controlled release … to the skin”

Opponents will argue the release is not “controlled” in the claimed sense or that release mechanism differs (e.g., reservoir/adhesive vs dispersed nicotine matrix). Literal infringement will hinge on matrix architecture and release testing.

3) Solidifying/gel-forming agent “selected from” lists

Because claim 6 enumerates many agent types, attackers may show the accused gel/solidifying system uses non-listed polymers or inorganic/organic combinations not captured by the categories. However, claim 6’s breadth reduces easy escape if the agent is plausibly within a listed family.

4) Solvent processing requirement

Claim 1 ties formation of the solid/semi-solid medium to the mixture being mixed/heated to form the medium from nicotine in a solution of solidifying/gel-forming agent in suitable solvent/solvent mixture. If an accused process is markedly different, a product may argue it falls outside claim 1’s structural formation limitation.

5) PK windows in method claims

The method claims 34–37 and 40–43 invite disputes around:

clinical sampling schedule,
assay method,
between-subject variability,
and whether the regimen produces plasma ranges within the specified windows.

What generic entry risks exist if a company attempts to launch a similar nicotine patch/gel?

A product that aims to copy the same therapeutic category (smoking cessation nicotine replacement) and uses a once-daily percutaneous controlled-release format faces layered risk:

Composition risk (claim 1 + claim 6 + claim 2 + nicotine mg range + excipient categories).
Form-factor/design risk (claim 3–4 surface area and thickness; claim 29–32 receptacle/patch and priming dose adhesive layer).
Method-of-use risk (claims 33–38, 39–43) if clinical PK aligns with “trough equivalence” and the ng/mL thresholds.

Most acute exposure arises when a competitor:

uses a matrix within the listed agent families,
hits similar dose loading,
and exhibits PK profiles consistent with the numeric windows and priming structure.

What is the Orange Book status of US 4,946,853?

No Orange Book listing can be derived from the claim text alone. US patent numbers do not map deterministically to Orange Book entries without the Orange Book publication data and the specific NDA/ANDA/RLD product linkage.

How does this patent compare with typical prior art and later nicotine replacement IP?

From claim architecture, US 4,946,853 resembles a mid-generation nicotine transdermal formulation patent that tries to cover:

controlled release in a nicotine-containing semi-solid matrix,
explicit excipient classes,
device-adaptive formats,
and PK targets.

Later nicotine replacement patents often shift toward:

alternative polymer systems not enumerated in earlier lists,
redesigned adhesive stacks and microstructure engineered for release,
and clinical/regimen refinements that seek to distinguish PK profiles.

US 4,946,853’s enumerated ingredient lists and explicit PK thresholds mean design-around requires careful matching of both formulation and release/PK outcomes.

Key claim map: what an accused product must do to infringe

Claim cluster	What is required (hard elements)	Common “litigation hooks”
Claim 1 (independent composition)	Once-daily percutaneous nicotine; uniformly distributed nicotine in solid/semi-solid medium; medium made from nicotine in solution of solidifying/gel-forming agent in suitable solvent(s), then mixed/heated; controlled release to skin	product formulation disclosure, manufacturing steps, release testing
Claim 2 (solvents)	solvent(s) limited to water/ethanol/stearyl alcohol/glycerol/EG/PG/silicone or mixtures	solvent selection and process records
Claim 3-4 (form factor)	surface area 2–15 cm²; thickness 0.5–3 mm	device geometry, laminate thickness
Claim 6-16 (matrix agents)	gel/solidifying agent selected from long enumerated list (plant extracts, gums, polysaccharides, alginates, waxes/hydrocarbons, carboxyvinyl polymer, minerals, silicon compounds)	agent identity and composition of matrix
Claim 17-18 (dose loading)	5–100 mg nicotine; 10–50 mg dependent	label strength vs matrix loading
Claim 19-28 (excipient categories)	“one or more” additive classes + enumerated examples	formula matching and supplier specs
Claim 29-30 (device integration)	in receptacle of skin-contact device; self-adhesive patch/plaster	product architecture and packaging/delivery instructions
Claim 31-32 (priming dose)	priming nicotine in adhesive layer permeable to nicotine; or priming in peripheral adhesive layer	multilayer adhesive design
Claim 33-38 (method)	once-daily percutaneous treatment of smoking cessation withdrawal with PK “trough equivalence”; PK numeric ranges; taper option	PK study design, clinical measurement, label regimen
Claim 39-43 (method)	psychological dependence treatment with same PK structure; PK numeric thresholds	the same PK and clinical evidence

Key Takeaways

US 4,946,853 combines formulation and method-of-treatment coverage for once-daily percutaneous nicotine using a controlled-release solid/semi-solid matrix.
The breadth is driven by (i) large enumerated solidifying/gel-forming agent categories and (ii) extensive dependent coverage of solvents, excipients, device integration, priming dose adhesive layers, and physical form factors.
The method claims add a second infringement pathway through plasma nicotine targets: explicit ng/mL within 1 hour and ng/mL ranges over 1–24 hours, plus tapering.
Design-around that changes only the active loading or only the dosing schedule is less likely to avoid both composition and method exposure; release profile and matrix architecture are central.

FAQs

1) Can a competitor avoid US 4,946,853 by changing the gel polymer family?
If the replacement agent falls outside the enumerated “solidifying or gel-forming agent” families in claim 6 (and dependent lists), claim 1/6 literal coverage is weakened, but controlled-release plus process and solvent elements still must be assessed.

2) Does the priming-dose limitation matter if the product has a nicotine “start-up” effect?
Yes for claims 31 and 32, which require priming dose placement within adhesive layers with defined permeability/position. Multilayer adhesive design determines fit.

3) How do the plasma nicotine thresholds affect method-of-use infringement?
Claims 34–37 and 40–43 require plasma concentrations above specified ng/mL levels within defined time windows. Matching PK endpoints is the core question.

4) Are surface area and thickness limitations strict, or can small variations avoid infringement?
Claims 3 and 4 are numeric ranges. A product outside the defined 2–15 cm² surface area or 0.5–3 mm thickness can avoid those dependent claims, though independent claim 1 may still apply.

5) Does US 4,946,853 cover nicotine itself, or only formulations?
The claims are to preparations (formulations) and methods of administering nicotine via controlled-release percutaneous solid/semi-solid media, not to nicotine as a standalone chemical entity.

References

US Patent 4,946,853. (n.d.). United States patent document (claims provided in prompt).

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Ireland	1119/87	May 01, 1987
Ireland	1946/87	Jul 17, 1987

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	161721	⤷ Start Trial
Australia	1534988	⤷ Start Trial
Australia	607214	⤷ Start Trial
Canada	1333051	⤷ Start Trial
Germany	3856096	⤷ Start Trial
Denmark	235088	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 4,946,853

Summary for Patent: 4,946,853