# United States Drug Patent RE39069: Claim Scope, Patent Expiration, Litigation Risk, and Pharmaceutical Landscape

United States Patent RE39069 is a broad formulation patent covering multi-layered osmotic dosage forms. Its central architecture combines a controlled-release osmotic core, a semipermeable membrane with a preformed delivery orifice, a soluble or erodible polymer layer that temporarily plugs the orifice, and an outer drug-containing layer for immediate or otherwise programmed release.

The patent is platform-oriented rather than directed to a single approved drug. Its listed active-agent combinations include theophylline, pseudoephedrine-loratadine, pseudoephedrine-astemizole, ranitidine-cisapride, and diltiazem-enalapril. The patent is expired and does not present a current United States blocking right for generic or branded products. Its historical importance is in osmotic delivery technology, not in current Orange Book exclusivity.

What technology does United States Patent RE39069 protect?

RE39069 protects a dosage form with sequential or programmed release from physically distinct layers. The required structure is:

A compressed core containing a first active agent and an osmotic agent.
A semipermeable membrane surrounding the core.
At least one preformed passageway in that membrane.
A water-soluble or erodible polymer coat that covers or plugs the passageway.
An external coat containing a second active agent.

The first agent remains isolated from the gastrointestinal environment until the plugging layer dissolves or erodes. The second agent is released from the external layer before, or independently of, the first agent.

The core inventive concept is therefore a delayed-opening osmotic tablet. The outer layer supplies an initial dose, while dissolution of the intermediate polymer coat exposes the osmotic membrane passageway and initiates controlled delivery from the core.

How many patents cover the RE39069 osmotic platform?

RE39069 is one patent in a broader Alza osmotic-delivery patent family and technology cluster. The relevant landscape includes patents directed to:

Osmotic cores and osmotic pressure-generating agents.
Semipermeable cellulose acetate membranes.
Laser-drilled or otherwise preformed delivery passageways.
Water-soluble and erodible overcoats.
Push-pull and bilayer osmotic tablets.
Immediate-release external drug layers.
Delayed, timed, sustained, and zero-order delivery.
Drug combinations delivered from separate layers.
Manufacturing processes for coating and orifice formation.

RE39069 should be analyzed as a formulation and device patent. It is not a compound patent, polymorph patent, salt patent, or biologic patent.

What are the independent claims in RE39069?

The principal independent claims are claims 1, 24, 25, 26, 27, 36, 49, and 52. They form several overlapping claim groups.

Claim group	Core scope	Important limitation
Claim 1	Multi-layered osmotic device with two active agents	Polymer coat specifically includes poly(vinylpyrrolidone)-vinyl acetate copolymer
Claim 24	Same general device architecture	External coat covers the inert polymer coat
Claim 25	Broad two-agent osmotic device	Requires immediate release of the second agent
Claim 26	Broad two-agent osmotic device	Does not require immediate release of the second agent
Claim 27	Broad release-profile version	Covers immediate, rapid, delayed, sustained, timed, and controlled release
Claim 36	Device with a specified polymer-coat composition	Requires PVP-vinyl acetate copolymer plus a second polymer
Claim 49	Device with PVP-vinyl acetate polymer coat	External coat contains the second active agent
Claim 52	PVP-vinyl acetate version with broad release profiles	Covers multiple release modes for the outer agent

Claims 24 through 27 are especially important because they do not always require the polymer coat to contain the specific PVP-vinyl acetate copolymer recited in claim 1. Claims 36, 49, and 52 restore that composition-specific limitation.

What elements must be present to infringe the core claims?

A potentially infringing product would generally need to satisfy all material limitations of at least one asserted claim. The main technical elements are cumulative.

Compressed osmotic core

The core must be compressed and contain:

A first active agent; and
At least one osmotic agent.

The osmotic agent generates the driving force for fluid entry and drug release. Conventional osmotic agents may include salts, sugars, and other osmotically active excipients, although the claim language is not limited to a particular osmogen.

A product using a non-osmotic matrix, reservoir, diffusion membrane, or conventional extended-release tablet would generally fall outside the core architecture unless it independently satisfies the osmotic-agent and membrane limitations.

Semipermeable membrane

The membrane must surround the core and be permeable to environmental fluid while being substantially impermeable to the first active agent.

Claim 3 narrows the membrane to a composition consisting essentially of cellulose acetate and polyethylene glycol. Claims 21, 37, and 51 cover membranes containing a plasticizer and one or more cellulose ether, cellulose ester, or cellulose-ester-ether materials.

The membrane is a functional barrier. It admits water or gastrointestinal fluid, retains the active agent, and allows pressure-driven delivery through the passageway.

Preformed passageway

The membrane must contain at least one preformed passageway. The claims do not limit the passageway to a specific manufacturing method, although laser drilling is a conventional implementation for osmotic tablets.

A dosage form in which the opening forms only by erosion, swelling, cracking, or dissolution may present a noninfringement position against claims requiring a preformed passageway. The factual question would be whether an opening existed in the membrane before exposure to the environment of use.

Inert soluble or erodible polymer coat

The polymer coat must partially or completely surround the membrane and plug the passageway. It must be inert and completely erodible or water soluble.

The coat creates the delay between initial release from the outer layer and controlled release from the core. The claims cover coats that dissolve or erode in the same environment as the external coat or in the same environment as the core.

Claim 1 and several dependent claims identify poly(vinylpyrrolidone)-vinyl acetate copolymer. Claims 23, 36, 38, 39, 49, 50, 52, and 53 address combinations with talc, polyethylene glycol, or another polymer.

External active-agent coat

The outer coat must contain a second active agent. In the broad claims, the second agent may be released immediately, rapidly, slowly, after a delay, in a sustained manner, or according to another listed profile.

The external layer distinguishes the patent from a single-agent osmotic tablet. It permits an initial dose of one agent and delayed delivery of another, or immediate and controlled delivery of the same agent from separate regions.

What formulations are protected by RE39069?

The claims cover several formulation categories.

Formulation type	Expressly covered
Same active agent in outer and core layers	Yes
Two different active agents	Yes
Immediate outer dose and delayed core dose	Yes
Sustained release from the core	Yes
Gastric release followed by distal gastrointestinal release	Yes
Same gastrointestinal environment for both agents	Yes
PVP-vinyl acetate polymer coat	Yes
Cellulose acetate/polyethylene glycol membrane	Yes, under dependent claims
PVP and polyethylene glycol external coat	Yes, under dependent claims
Non-therapeutic agents	Yes, under claims 34 and 35
Single-layer conventional matrix tablet	No, absent the claimed osmotic architecture
Injectable or transdermal dosage form	No, absent the claimed device structure

Claims 34 and 35 extend the active-agent categories beyond prescription medicines. They include antibacterial, antihistamine, decongestant, cardiovascular, antihypertensive, gastrointestinal, cosmetic, nutritional, agricultural, diagnostic, and chemical agents.

Which drug combinations are specifically named in RE39069?

Claims 9 through 14 and claims 41 through 49 identify representative combinations.

Core agent	External agent	Claim
Theophylline	Theophylline	9, 45
Pseudoephedrine	Loratadine	11, 43
Ranitidine	Ranitidine and cisapride	12, 41
Pseudoephedrine	Astemizole	13, 42
Diltiazem	Enalapril	14, 44
Decongestant	Antihistamine	46
First antihypertensive	Different second antihypertensive	47
Gastric acid inhibitor	Gastrointestinal emptying adjunct	48

These claims are formulation claims. They do not grant exclusivity over the active ingredients themselves.

Several listed combinations have limited present-day commercial significance:

Astemizole was withdrawn in the United States because of cardiac safety concerns.
Cisapride was withdrawn from broad United States marketing and became available only through restricted access arrangements.
Ranitidine was withdrawn from the United States market after FDA action relating to N-nitrosodimethylamine contamination.
Loratadine, pseudoephedrine, theophylline, diltiazem, and enalapril remain associated with marketed or historically marketed products, but the patent does not provide current exclusivity for those compounds.

FDA, 2020a, 2020b; FDA, 2023.

How broad are the claims compared with the narrow composition claims?

The broadest practical claim set is claims 24 through 27. These claims focus on the physical architecture and release relationship rather than requiring a particular polymer chemistry.

Claims 36, 49, and 52 are narrower because they require PVP-vinyl acetate copolymer in the intermediate coat. A competing formulation using a different soluble or erodible polymer could have a stronger noninfringement position against those claims, although it could still face analysis under claims 24 through 27.

The release language also varies:

Claim 25 requires immediate release of the second agent.
Claim 26 allows release without requiring immediacy.
Claim 27 expressly lists a wide range of release profiles.
Claim 52 combines the broad release language with the PVP-vinyl acetate limitation.

Claims 28 through 35 and 39 through 54 largely define dependent variations involving agent identity, environment of use, membrane composition, polymer mixtures, and release timing.

What is the patent expiration status of RE39069?

RE39069 is expired. The reissue date does not restart the patent term. United States patent term is generally calculated from the earliest effective nonprovisional filing date for the underlying patent family, subject to applicable patent-term adjustment, terminal disclaimers, and statutory exceptions. A reissue patent ordinarily retains the term of the original patent. 35 U.S.C. §§ 154, 251, 252.

The operative commercial conclusion is that RE39069 no longer creates an enforceable United States exclusivity period. The USPTO patent record and official Patent Center file history are the controlling sources for the underlying patent, reissue prosecution, maintenance-fee history, and term calculation. USPTO, n.d.-a; USPTO, n.d.-b.

What is the Orange Book status of RE39069?

RE39069 is not a conventional Orange Book drug patent. It is a platform formulation patent covering a multi-layered osmotic device and numerous possible active agents.

The FDA Orange Book generally lists patents submitted by an approved-new-drug applicant that claim the drug substance, drug product, or an approved method of use. A broad, expired platform patent is not equivalent to current Orange Book protection for a specific product. No current Paragraph IV strategy should be inferred from RE39069 alone. FDA, n.d.

If the patent was historically submitted for an approved product, the relevant product-specific listing and delisting history would need to be evaluated separately from the patent’s broad claim language. The patent itself does not establish a current regulatory barrier.

When does a generic lose exclusivity risk under RE39069?

A generic product faces no current patent-term risk from RE39069 because the patent is expired. During the historical term, risk would have depended on whether the proposed dosage form used:

A preformed orifice in a semipermeable membrane.
An osmotic compressed core.
A dissolving or eroding polymer plug.
An external layer containing a second active agent.
The same or different active agents in the two layers.
A delayed relationship between the outer and core doses.

A conventional extended-release formulation that uses a matrix, diffusion membrane, coated pellets, or multiparticulate beads would not automatically infringe. The patent is directed to a specific tablet or device architecture, not to every controlled-release product.

Were Paragraph IV challenges or litigation associated with RE39069?

The claims are broad enough that a marketed product using the claimed architecture could historically have created Paragraph IV or district-court litigation exposure. The patent’s present status changes the analysis: an abbreviated new drug application filed today would not need to provide a Paragraph IV certification against an expired patent as a live patent barrier.

A complete litigation determination requires matching the patent against court dockets, ANDA litigation records, and product-specific FDA submissions. The patent number alone does not establish that a particular generic applicant challenged RE39069, that a settlement was signed, or that a court construed the claims.

The practical risk profile is:

Issue	Current assessment
Live patent term	No
Current Orange Book exclusivity	Not established by RE39069
Current Paragraph IV barrier	No
Historical formulation risk	Material for products using the claimed architecture
Current freedom-to-operate value	Limited as a blocking right
Prior-art value	High for osmotic, layered, and timed-release formulations
Settlement relevance	Only if tied to a specific historical product and docket

How strong is the RE39069 patent estate?

As an expired patent, its current blocking strength is zero. Its historical claim breadth was stronger in formulation architecture than in drug-specific protection.

Historical strengths

Multiple overlapping independent claim groups.
Coverage of same-agent and combination-agent products.
Coverage of immediate, delayed, sustained, and timed release.
Broad active-agent categories.
Claims directed to both the device structure and polymer-coat composition.
Coverage of same and different gastrointestinal environments.

Historical weaknesses

The claims require a multi-layered osmotic architecture.
The membrane must have a preformed passageway.
The polymer layer must plug that passageway.
The first agent must be released after dissolution or erosion of the polymer coat.
Several narrower claims depend on PVP-vinyl acetate copolymer.
Named drug combinations do not create compound exclusivity.
Prior art in osmotic cores, semipermeable membranes, drilled orifices, and soluble coatings could have supported validity challenges.

The principal claim-construction disputes would likely have concerned the meanings of "preformed passageway," "plugging," "completely erodible or water soluble," "external coat," "immediate release," and "after the polymer coat has partially or completely dissolved or eroded."

What manufacturing and intellectual-property barriers did the patent create?

The technical barrier was process integration. A manufacturer needed to produce, in sequence:

A compressed osmotic core.
A uniform semipermeable membrane.
A reliable passageway through that membrane.
A polymer coat positioned to plug the passageway.
An external drug-containing layer.
Reproducible dissolution and release timing.

Critical quality attributes included membrane thickness, orifice diameter, polymer-coat weight, coat uniformity, osmogen loading, core hardness, and dissolution performance. Variability in any of these parameters could change the delay period or the subsequent osmotic release rate.

The patent did not eliminate other barriers. Manufacturing know-how, coating equipment, scale-up data, dissolution specifications, formulation stability, and regulatory bioequivalence requirements could remain significant even after patent expiry.

How does RE39069 compare with competing osmotic delivery patents?

RE39069 differs from conventional osmotic patents in its emphasis on a temporary polymer plug and a drug-containing external coat.

Patent category	Primary protection	Difference from RE39069
Basic osmotic tablet patents	Core, membrane, osmogen, orifice	May lack the erodible plugging layer and external active layer
Push-pull osmotic patents	Expandable push layer and drug layer	Use swelling or mechanical displacement rather than a soluble plug
Coated-pellet patents	Multiparticulate controlled release	Do not require a single compressed osmotic core
Enteric dosage-form patents	pH-triggered protection or release	May not use osmotic pressure or a preformed orifice
Layered immediate/extended-release tablets	Separate release layers	Usually lack the semipermeable membrane and osmotic core
RE39069	Osmotic core plus plugged passageway plus outer active layer	Combines delayed access with multi-agent release

The closest technical prior art is likely to include Alza and other controlled-release patents involving osmotic cores, cellulose acetate membranes, drilled passageways, water-soluble coatings, and combination products. A product-by-product comparison remains necessary because infringement turns on the claimed combination of elements.

What generic launch scenarios remain after RE39069 expires?

A generic or follow-on manufacturer can generally pursue several designs without current RE39069 patent-term exposure:

A conventional matrix extended-release tablet.
A multilayer tablet without a semipermeable osmotic membrane.
An osmotic tablet using a different release architecture.
A multiparticulate system with coated pellets.
A capsule containing immediate- and extended-release components.
A formulation without a preformed membrane passageway.
A system in which the external agent is not released from a coat covering a plugging layer.

Regulatory requirements remain product-specific. A generic must satisfy the applicable FDA abbreviated pathway, including pharmaceutical equivalence, bioequivalence, labeling, quality, and manufacturing requirements. Patent expiry removes one barrier but does not guarantee approval or commercial success.

What revenue exposure was associated with the patent?

RE39069 does not support a reliable current revenue estimate because it is not tied to one approved product or one active ingredient. Historical revenue exposure would have depended on whether a marketed product used the claimed layered osmotic configuration and whether the patent was listed against that product.

The named products and combinations indicate potential historical exposure in:

Allergy and decongestant combinations.
Gastrointestinal therapy.
Cardiovascular therapy.
Theophylline controlled delivery.
Combination antihypertensive therapy.

That exposure is now principally historical. Any current commercial assessment should focus on successor patents, product-specific formulation patents, regulatory exclusivity, trademarks, manufacturing know-how, and market authorization status.

Key Takeaways

RE39069 covers a multi-layered osmotic dosage form, not a drug molecule.
Its defining structure is an osmotic core, semipermeable membrane, preformed passageway, soluble or erodible polymer plug, and external active-agent coat.
Claims 24 through 27 provide the broadest architecture-focused coverage.
Claims 1, 36, 49, and 52 add PVP-vinyl acetate copolymer limitations.
The patent covers same-agent and combination-agent products, including theophylline, pseudoephedrine-loratadine, ranitidine-cisapride, pseudoephedrine-astemizole, and diltiazem-enalapril.
RE39069 is expired and does not provide current United States patent exclusivity.
The patent is not, by itself, a current Orange Book or Paragraph IV barrier.
The main historical validity and infringement issues would have involved the preformed passageway, polymer plug, release sequence, and multi-layer structure.
Current freedom-to-operate analysis should prioritize later patents and product-specific patent families rather than RE39069.

FAQs About United States Patent RE39069

Does RE39069 protect loratadine or pseudoephedrine as active ingredients?

No. The patent covers a dosage-form configuration containing those agents. It does not claim loratadine or pseudoephedrine as chemical compounds.

Can a generic use the same drug combination after RE39069 expires?

Yes, subject to other applicable patents, regulatory requirements, labeling restrictions, and manufacturing obligations. RE39069 itself no longer creates a live patent barrier.

Does a tablet need a laser-drilled hole to fall within RE39069?

Not necessarily. The claims require a preformed passageway but do not expressly require laser drilling. Another manufacturing method could satisfy that limitation if it creates the required passageway before use.

Could a multiparticulate capsule infringe RE39069?

It would not automatically infringe. The product would need to satisfy the claim limitations, including the compressed osmotic core, surrounding semipermeable membrane, plugged passageway, and external active-agent coat.

Is RE39069 relevant to modern controlled-release biologics?

Usually not. The claims are directed to oral osmotic devices and active agents broadly, but biologic products generally use different formulation, delivery, stability, and regulatory technologies. A biologic product would need to satisfy every structural limitation to create a credible infringement theory.

References

Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services.

Food and Drug Administration. (2020a). FDA requests removal of all ranitidine products from the market. U.S. Department of Health and Human Services.

Food and Drug Administration. (2020b). FDA warns about increased risk of cancer with heartburn medicine ranitidine. U.S. Department of Health and Human Services.

Food and Drug Administration. (2023). Cisapride information. U.S. Department of Health and Human Services.

United States Patent and Trademark Office. (n.d.-a). Patent Center: United States Patent RE39069 file history. U.S. Department of Commerce.

United States Patent and Trademark Office. (n.d.-b). Manual of Patent Examining Procedure, reissue applications and patent term provisions. U.S. Department of Commerce.

35 U.S.C. §§ 154, 251, 252.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Argentina	P97 01 02351	May 30, 1997

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	007358	⤷ Start Trial
Austria	250929	⤷ Start Trial
Australia	7706598	⤷ Start Trial
Brazil	9802144	⤷ Start Trial
Brazil	PI9802144	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: RE39069

Summary for Patent: RE39069