Details for Patent: 6,024,976

Summary for Patent: 6,024,976

Title:	Solubility parameter based drug delivery system and method for altering drug saturation concentration
Abstract:	A blend of at least two polymers, or at least one polymer and a soluble polyvinylpyrrolidone, in combination with a drug provides a pressure-sensitive adhesive composition for a transdermal drug delivery system in which the drug is delivered from the pressure-sensitive adhesive composition and through dermis when the pressure-sensitive adhesive composition is in contact with human skin. According to the invention, soluble polyvinylpyrrolidone can be used to prevent crystallization of the drug, without affecting the rate of drug delivery from the pressure-sensitive adhesive composition.
Inventor(s):	Jesus Miranda, Steven Sablotsky
Assignee:	DONATIELLO GUY , Noven Pharmaceuticals Inc
Application Number:	US08/907,906
Patent Claim Types: see list of patent claims	Composition; Compound; Delivery; Device;

Scope and Patent Landscape for US Patent 6,024,976: Transdermal Pressure-Sensitive Adhesive Blends Using Synthetic Elastomers, Soluble PVP, and Specific Drug Payloads

US 6,024,976 claims transdermal pressure-sensitive adhesive (PSA) technology built around a specific adhesive formulation architecture: (i) a synthetic elastomeric polymer (including polysiloxanes in narrower claims), (ii) a soluble polyvinylpyrrolidone (PVP), and (iii) at least one drug, optionally combined with multiple classes of excipients (enhancers, plasticizers, fatty acids/alcohols, and clays). The claim set spans broad generic claim language (“at least one drug”) plus extensive dependent claims that enumerate drug classes and named active ingredients (including alprazolam, clonazepam, clonidine, estradiol, norethindrone acetate, fludrocortisone acetate, ketoprofen/“keptprofen” as written, methylphenidate, terbinafine, and multiple others), and also adds structural system features (sheet, geometric shape, backing impervious to the drug, release liner, and reservoir device architecture).

What patents protect the transdermal adhesive blend claimed in US 6,024,976?

US 6,024,976 is best understood as a platform PSA composition claim with drug-listing coverage. The independent claims in your excerpt are composition/system claims; the dependent claims do two things: tighten polymer chemistry and system architecture, and lock down formulation ranges for particular drugs and excipient packages.

What the broadest independent claim scope covers (claim 1 and claim 13)

Claim 1 (composition-focused):
A transdermal drug delivery system comprising a PSA composition including:

1. a synthetic elastomeric polymer,
2. a soluble PVP, and
3. at least one drug.

This claim is “open” on both polymer selection (subject to the elastomeric requirement) and drug selection (subject only to “at least one drug,” then narrowed later by dependent claims).

Claim 13 (system-focused with additional adhesive polymer class):
A transdermal drug delivery system with a PSA blend including:

1. a synthetic elastomeric polymer,
2. a polyacrylate polymer,
3. soluble PVP, and
4. at least one drug.

Claim 13 requires an additional polymer component (polyacrylate) and therefore narrows away from PSA compositions that only use the elastomeric polymer + PVP.

How polymer selection is narrowed (claims 2 and 20-25 and 21-23)

Key narrowing dependent claims include:

• Claim 2: synthetic elastomeric polymer is a polysiloxane.
• Claim 20: synthetic elastomeric polymer is present 14% to 94% by weight of the total PSA composition.
• Claim 21: again limits the elastomeric polymer to polysiloxane.
• Claim 22: polyacrylate polymer present 5% to 85% by weight.
• Claim 23: elastomeric polymer and polyacrylate differ in solubility parameter by ≥ 2 (J/cm3)1/2.
• Claims 24-25: soluble PVP present 1% to 20%; and PVP molecular weight 44,000 to 54,000.

How PVP is constrained (claims 24-26)

• Claim 24: soluble PVP is present 1% to 20% by weight.
• Claim 25: PVP molecular weight 44,000 to 54,000.
• Claim 26: drug present 0.1% to 50% by weight (broad to mid-range).

What excipient/enhancer coverage exists (claims 3, 27-28, 29-30, 4-12)

• Claim 3: blend further contains at least one enhancer.
• Claim 27: enhancer is present 1% to 20% (when dependent on claim 13).
• Claim 29-30: system further comprises clay, including bentonite.

Claims 4-12 in your excerpt are unusually specific: they provide numerical PSA composition ranges and name specific drugs. They create strong “formulation coverage” for accused products that replicate those exact excipient packages and ratios.

Which drug actives are explicitly claimed in US 6,024,976?

The dependent claims enumerate drug categories and then list specific actives. Practically, this gives the patent two layers of enforceability: (i) a platform argument under claim 1/13 (“at least one drug”), and (ii) formulation-specific arguments when an accused product uses one of the enumerated actives plus matching PSA excipient architecture.

Drug category map from the dependent claims

• Steroids/estrogens/progestational agents

  • Estrogens (claim 32): conjugated estrogens, esterified estrogens, estropipate, 17β-estradiol, equilin, mestranol, estrone, estriol, ethinyl estradiol, diethylstilbestrol.
  • Specific estrogen loading (claim 33): 17β-estradiol at 0.1% to 5%.
  • Progestational agents (claim 35): extensive list including norethindrone acetate.
  • Specific progestational loading (claim 36): norethindrone acetate at 1% to 5%.
  • Mixtures of progestational agent + estrogen (claims 37-41 and 40-41).

• β2-adrenergic agonists (claims 42-44): including metaproterenol, terbutaline, albuterol, carbuterol, etc.

  • Albuterol specific (claim 44): less than 30% by weight.

• Cardioactive agents (claims 45-47): including nitroglycerin, isosorbide dinitrate/mononitrates, quinidine sulfate, procainamide, chlorothiazide, nifedipine, nicardipine, verapamil, diltiazem, timolol, propranolol, captopril, clonidine, prazosin.

  • Nitroglycerin specific (claim 47): less than 25% by weight.

• Cholinergic agonists (claims 48-50): choline, acetylcholine, methacholine, carbachol, bethanechol, pilocarpine, muscarine, arecoline.

  • Pilocarpine specific (claim 50): less than 30% by weight.

• Tranquilizers/benzodiazepines (claims 51-53): includes alprazolam (and many others), with alprazolam specified via claim 53.

• Antipsychotics (claims 54-56): includes haloperidol (claim 56) and others.

• Anesthetics (claims 57-59): includes lidocaine (claim 59).

• Analgesics (claims 60-61): fentanyl, buprenorphine, codeine.

• Central nervous system action including nicotine (claim 62-63): nicotine.

• Vasodilators (claims 64-65): papaverine.

• At least two drugs (claim 66).

Named specific actives in the composition-range claims 4-12

Claims 4-12 (as provided) hard-wire drug names into specific PSA formulation ranges. Actives explicitly listed there include:

• Alprazolam (claim 4) with silicone adhesive / PVP / dipropylene glycol / oleic acid, and numeric ranges.
• Clonazepam (claim 5) with silicone adhesive + acrylic adhesive + PVP + dipropylene glycol + oleyl alcohol and numeric ranges.
• Clonidine (claim 6).
• Fludrocortisone acetate (claim 7).
• Keptprofen (claim 8; likely intended ketoprofen, but as written it is “keptprofen”) with acrylic/silicone adhesives + PVP + oleic acid and numeric ranges.
• Methylphenidate (claims 9-10) with silicone + acrylic + PVP and numeric ranges.
• Terbinafine (claim 11) with silicone + acrylic + PVP and numeric ranges.
• Estradiol (claim 12) with silicone + acrylic + PVP + optional dipropylene glycol and oleyl alcohol and numeric ranges.

From an infringement-risk perspective, these numeric-dependent claims are the most leverage for enforcement because an accused product can be tested against ranges directly.

What transdermal system hardware is protected in US 6,024,976?

US 6,024,976 includes dependent claims on device architecture, not only adhesive composition. The hardware scope includes:

• Defined geometric shape (claim 14).
• Sheet form (claim 15).
• Individual dosage unit (claim 16).
• Backing material substantially impermeable to the drug (claim 17).
• Release liner over the PSA surface opposite the backing (claim 18).
• Reservoir device having an adhesive portion comprised of the blend (claim 19).

These features matter for design-around. A competitor could potentially keep the same adhesive chemistry but use a non-reservoir design or alter liner/backing configurations to avoid falling under specific dependent claims.

How broad is the “pressure-sensitive adhesive blend” claim coverage?

Claim breadth split: platform vs. formulation-range vs. drug-class

• Platform layer (highest breadth):

  • Claim 1: synthetic elastomeric polymer + soluble PVP + drug.
  • Claim 13: elastomeric polymer + polyacrylate polymer + soluble PVP + drug. These are broad enough to cover multiple drug candidates if the adhesive system uses the required polymer architecture.

• Material-property/ratio layer:

  • Claims 20-25 constrain polymer identity (polysiloxane) and concentration ranges and PVP molecular weight.
  • Claim 23 adds solubility parameter separation (≥ 2 (J/cm3)1/2).

• Drug-specific formulation-range layer:

  • Claims 4-12 specify silicone/acrylic/specific excipients and numeric drug loading ranges for enumerated actives.

• Drug-class category layer:

  • Claims 31-65 cover drug “types” (steroid, β2-agonist, cardioactive, cholinergic agonist, tranquilizer, antipsychotic, anesthetic, analgesic, nicotine/CNS, vasodilator) with named members.

Practical consequence for enforcement

A patentee can pursue multiple claim pathways:

• Show an accused product matches claim 1 or 13 architecture, then argue literal infringement even if drug is not specifically listed.
• Alternatively, map the accused product to dependent claim formulations (numeric ranges, PVP Mw, elastomer type, solubility parameter gap).
• Use device architecture dependent claims if the accused product is a sheet with backing/liner consistent with the claims.

When does US 6,024,976 lose exclusivity?

The question turns on the patent’s expiration and any extension, but the provided record does not include the filing date, priority date, term adjustment, or any PTA/TOT reference. Without those inputs, an accurate exclusivity timeline cannot be produced.

What is the Orange Book status of US 6,024,976?

Orange Book status requires identifying the associated NDA/ANDA/BLA references and the Orange Book listed patents (with corresponding patent numbers and expiration dates). The provided input does not include any Orange Book listing linkage for US 6,024,976, so status cannot be determined from the excerpt.

What generic entry risks exist for transdermal products using PSA blends like this?

Litigation posture usually depends on how claim 1/13 maps to commercial formulations

For generic and 505(j) entry risk, the critical question is whether a generic applicant must certify to and is exposed by the specific listed patents. If US 6,024,976 is listed for a specific approved transdermal product, the risk becomes visible as:

• Paragraph IV for that NDA/ANDA, if the patent is asserted and a listing exists; and/or
• Design-around by altering adhesive composition away from required features (soluble PVP presence, polymer architecture, polymer type, solubility parameter relationship, or numeric ranges) and/or altering reservoir vs matrix/sheet architecture and backing/liner.

From the claim structure, the highest-risk “copy targets” are:

• Adhesive system using both synthetic elastomeric polymer and soluble PVP,
• and products containing polysiloxane elastomer and matching PVP Mw range,
• with enhancer/clay packages consistent with claims 3/27-30.

How can competitors design around US 6,024,976?

This is determined by whether they can avoid every element of the relevant independent claims and key dependent constraints.

Design-around levers surfaced by the claim text

1. Remove or replace “soluble PVP”
   Claim 1/13 require soluble PVP. Changing to an insoluble polymer, or using a different hydrophilic binder outside “soluble PVP,” is an obvious avoidance vector.

2. Change elastomeric polymer away from required architecture
   Claim 13 specifically requires both synthetic elastomeric polymer and polyacrylate polymer. Avoiding the polyacrylate requirement could steer away from claim 13.

3. Avoid polysiloxane + solubility parameter relationship
   Claims 2 and 21 require polysiloxane. Claims 20-23 constrain solubility parameter difference when polyacrylate is present.

4. Avoid matching the numeric formulation ranges for the listed actives
   If a product uses one of the drug-specific actives enumerated in claims 4-12, matching the exact PSA excipient ranges increases infringement risk. Shifting concentrations outside the claimed ranges is a direct mitigation.

5. Alter device architecture to break dependent claim elements
   Claims 14-19 restrict sheet/geometric shape and backing/liner/resevoir architecture. Changing the device format can reduce exposure to these dependent claims.

Patent landscape: what other patents likely cluster around US 6,024,976?

Your excerpt provides claims, but not bibliographic data (assignee, filing date, priority), nor citations, family members, continuations, or co-pending related patents. Without those, a complete landscape cannot be constructed without risking inaccuracies. The claim language itself indicates the patent sits in a cluster of transdermal PSA “platform” compositions and drug-specific matrices commonly associated with benzodiazepines, steroids, NSAIDs/analgesics, antifungals, stimulants, and cardiovascular actives.

Key Takeaways

• US 6,024,976 protects transdermal PSA drug delivery systems built on a three-element adhesive architecture: synthetic elastomeric polymer + soluble PVP + drug (claim 1), and a narrower but still broad variant requiring polyacrylate polymer (claim 13).
• Dependent claims add high-value constraints: polysiloxane elastomer, specific loading ranges (for elastomer, polyacrylate, PVP), PVP molecular weight (44,000 to 54,000), and a solubility-parameter separation (≥ 2 (J/cm3)1/2).
• The claim set includes both platform drug coverage (“at least one drug”) and detailed drug-class and named-active coverage, including alprazolam, clonazepam, clonidine, fludrocortisone acetate, estradiol, norethindrone acetate (and other progestins), methylphenidate, terbinafine, and multiple other actives.
• The patent also covers device and packaging elements: sheet/geometric shapes, backing impermeable to drug, release liner, and reservoir device architecture.
• Design-around vectors are identifiable from the claim elements: remove/replace soluble PVP, avoid polyacrylate in the claim-13 blend, avoid polysiloxane and the solubility parameter relationship, shift drug/excipient concentrations outside enumerated ranges, and change device architecture.

FAQs

1) Does claim 1 require a particular drug class or named active ingredient?
No. Claim 1 requires only “at least one drug,” with drug classes and named actives appearing in dependent claims.

2) What is the main formulation differentiator between claim 1 and claim 13?
Claim 13 adds a required polyacrylate polymer component to the PSA blend.

3) Are the PVP requirements purely qualitative or do they include quantitative constraints?
They include both: claim 24 limits PVP to 1% to 20%, and claim 25 narrows soluble PVP molecular weight to 44,000 to 54,000.

4) Can a competitor avoid infringement by switching elastomer chemistry away from polysiloxane?
It can reduce risk against polysiloxane-dependent claims (claims 2 and 21), but claim 1 can still read on other synthetic elastomeric polymers.

5) Does the patent cover just the adhesive, or also the assembled patch?
It covers both. Dependent claims include geometric shape, backing impermeability, release liner, and reservoir-device architecture.

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References

1. United States Patent 6,024,976. “Transdermal drug delivery system comprising a pressure-sensitive adhesive composition…” (claims as provided).

Drugs Protected by US Patent 6,024,976

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 6,024,976

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	002355
Austria	122240
Austria	144704
Austria	148633
Austria	223185