Details for Patent: 5,292,515
Summary for Patent: 5,292,515
| Title: | Manufacture of water-swellable hydrophilic articles and drug delivery devices | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Abstract: | A method of preparing a hydrophilic plastic cartridge by centrifugally casting polymerizable hydrophilic material in a rotating polymerization tube whose longitudinal axis is maintained parallel to the ground. The speed of rotation causes radial outward displacement of the polymerizable material which upon assuming a predetermined shape within the rotating tube is then polymerized to the predetermined solid configuration. The resulting plastic cartridge is characterized by smooth, unscored internal and external cylindrical surfaces. The cartridges are used as a rate-limiting membrane in drug delivery devices. Sterilized kits containing a disposable needle/syringe or trocar-like instrument and the drug delivery device are used for subcutaneous implantation of the device in an animal body. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Inventor(s): | Daniel G. Moro, Petr Kuzma, Harry Quandt | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assignee: | Endo Pharmaceuticals Solutions Inc | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Application Number: | US08/041,523 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Patent Claim Types: see list of patent claims | Use; Composition; Delivery; Device; | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Patent landscape, scope, and claims: | United States Patent 5,292,515: Claim Scope, Expiration, and Drug-Delivery Patent LandscapeU.S. Patent No. 5,292,515 covers a hydrogel or xerogel implant designed for sustained drug release. Its core technology is a centrifugally cast, hollow, uniform-wall hydrophilic cartridge sealed with a second polymer plug that has a higher equilibrium water content. The claims extend across manufacturing, cartridge structure, drug loading, implantation by needle, and a sterile implantation kit. The patent is device- and process-focused rather than drug-specific. It does not claim luteinizing hormone-releasing hormone, growth hormone, or another active ingredient as a compound. Those agents appear as claimed uses and embodiments. The patent’s enforceable term has expired or, at the latest, ended many years ago under the standard 20-year patent-term framework, leaving no current United States exclusivity based on this patent alone.[1, 2] What technology does U.S. Patent 5,292,515 protect?The patent protects an implantable, cylindrical drug reservoir made from a biocompatible, non-biodegradable, hydrophilic polymer. The cartridge has:
The claimed operating principle is diffusion-controlled release through the hydrophilic polymer barrier. Water enters the polymer, the material swells, and drug diffuses through the cartridge or sealing structure over an extended period. The principal materials include polymers formed from hydrophilic ethylenically unsaturated monomers. Claim 24 narrows the cartridge to a polymer of 2-hydroxyethyl methacrylate, commonly known as HEMA. Claims 4 and 20 identify specific manufacturing variations involving benzoin methyl ether, ultraviolet radiation, and water-soluble pore-forming agents. How are the claims organized?The 42 claims divide into six principal claim groups.
Independent claims 1, 8, 21, 26, 36, and 41 define the main legal perimeter. The dependent claims add material, shape, drug, polymerization, hydration, and implantation limitations. What does independent claim 1 cover?Claim 1 covers a method for making a hollow plastic cartridge by centrifugal casting. The process requires:
The claim is narrower than a general hydrogel-molding claim. It requires the specific combination of horizontal rotation, centrifugal displacement, and polymerization within the rotating tube. What limitations are most important in claim 1?The most material limitations are:
A competing manufacturer using injection molding, extrusion, machining, or vertical casting would not literally practice every limitation of claim 1. It could still face risk under another claim, particularly claim 21 or claim 26, if the resulting cartridge and delivery device satisfy their structural limitations. What do claims 2 through 7 add?Claims 2 through 7 narrow the manufacturing process by specifying polymer chemistry and post-processing.
Claim 4 is highly specific. A process using a different photoinitiator or thermal initiation may avoid the claim 4 limitation while still implicating claim 1 or claim 2. The xerogel and hydrogel distinctions concern hydration state. A xerogel is the relatively dry polymer state. A hydrogel contains absorbed water and has reached or is approaching an equilibrium hydrated condition. What does claim 8 cover?Claim 8 covers a method of preparing the finished drug-delivery device. The method requires:
Claim 8 is important because it claims in situ formation of the seal after drug loading. The sealing polymer is not merely a mechanical cap. It is formed from liquid monomer within the reservoir opening and has a different hydration profile from the cartridge body. How do claims 11 through 20 narrow claim 8?Claims 11 through 16 identify drug and macromolecular-agent embodiments:
Claims 17 through 20 add xerogel, hydrogel, equilibrium hydration, and pore-forming-agent limitations. These claims do not create composition-of-matter rights in the listed hormones or proteins. They cover use of those agents within the claimed cartridge-and-plug delivery architecture. What physical cartridge does claim 21 protect?Claim 21 is the broadest standalone article claim. It covers a cartridge having:
Unlike claim 1, claim 21 does not require centrifugal casting. A cartridge made by another process could fall within claim 21 if it possesses the claimed structural characteristics. Claims 22 and 23 distinguish xerogel and hydrated states. Claim 24 narrows the polymer to HEMA. Claim 25 adds a scored internal surface near the open end treated with a mono- or polyhydric alcohol to improve graft polymerization. What is the significance of claim 25?Claim 25 protects a cartridge preparation technique designed to improve attachment of the sealing polymer to the cartridge wall. The scoring and alcohol treatment create a more favorable surface for graft polymerization. A manufacturer using a separate mechanical cap, adhesive, thermal weld, or chemically unrelated sealing method would have a stronger non-infringement position against claim 25. Claims 21 and 26 would require separate analysis because they focus on the cartridge and completed device. What does claim 26 cover?Claim 26 is the principal finished-device claim. It requires all of the following:
The relative hydration limitation is a central point. A device with a plug that does not have a greater equilibrium water content than the cartridge may avoid literal infringement of claim 26, depending on claim construction and the technical evidence. Claims 27 through 35 narrow the device to drugs, macromolecules, proteins, hormonal polypeptides, LHRH, growth hormone, growth-releasing hormone, and pharmaceutical carriers. What do claims 36 through 42 protect?Claim 36 covers implantation by perforation. The method requires a hollow needle containing the delivery device, subcutaneous injection, deposition at a selected site, and needle withdrawal. Claims 37 through 40 narrow the active agent and hydration state. Claim 41 covers a kit containing:
Claim 42 defines the delivery means as a rigid hollow tube with a needle-like opening and a telescoping solid rod that ejects the implant. These claims are directed to administration infrastructure. They would not ordinarily cover a drug manufacturer’s active ingredient, a conventional oral dosage form, or a transdermal patch. When did U.S. Patent 5,292,515 lose exclusivity?The patent’s term is governed by the pre- and post-1995 transition rules and the 20-year term measured from the earliest effective nonprovisional filing date, subject to any patent-term adjustment or terminal disclaimer.[2] Because U.S. Patent 5,292,515 issued in 1994, its enforceable term would ordinarily have ended no later than the early 2010s unless an unusual term adjustment or related legal circumstance applied. As of 2026, the patent is not a live barrier to manufacture, sale, use, or importation of a product that would have fallen within its claims during the patent term. Patent expiration removes the ability to obtain infringement damages or injunctive relief for post-expiration conduct under this patent. It does not erase the patent’s historical relevance as prior art or as a technical disclosure. What is the Orange Book status of U.S. Patent 5,292,515?U.S. Patent 5,292,515 is not an Orange Book drug patent based on the claim text and technology. The Orange Book principally records patents submitted for approved drug products, including patents claiming the drug substance, drug product, or approved method of use.[3] This patent claims:
Those claims are not directed to a chemical drug substance or a conventional pharmaceutical formulation. An approved drug using a device based on this technology could raise separate product-specific listing questions, but the patent itself is not a typical Orange Book-listed active-ingredient patent. Does the patent create biosimilar risk?No direct biosimilar risk arises from this patent. The patent does not claim a biologic drug, protein sequence, antibody, recombinant product, or manufacturing cell line. Claims 13 through 16 and 31 through 34 merely identify proteins and hormones as active agents used in the device. Biosimilar exposure would depend on separate patents covering:
Because this patent has expired, it does not independently block a biosimilar sponsor from using a hydrogel implant architecture that otherwise complies with current regulatory requirements. Which companies could challenge or design around the patent?During the patent term, likely design-around routes included:
The most important competitive alternatives historically included osmotic implants, biodegradable microspheres, reservoir implants with membrane barriers, injectable depot formulations, and implantable pump systems. Those systems may have separate patent estates and regulatory requirements. How strong was the patent estate?The patent had meaningful historical coverage because it claimed the same platform at multiple levels:
That layered structure reduced the importance of any single claim. A competitor avoiding the centrifugally cast manufacturing process could still face the article or finished-device claims if it produced a cartridge with the required geometry and polymer characteristics. The estate also had limitations. Many claims require a specific combination of:
A competing system using a different release mechanism, geometry, material class, or closure method could potentially avoid the principal claims. Today, the estate has no meaningful exclusionary strength because the patent term has ended. Its remaining value is technical and historical rather than blocking. What patent litigation or settlement agreements affect this patent?The claim text alone does not establish a current infringement action, Paragraph IV certification, or settlement agreement involving U.S. Patent 5,292,515. The patent is not a conventional small-molecule Orange Book patent, so a standard generic-drug Paragraph IV dispute would not ordinarily center on this patent. Under the Hatch-Waxman framework, Paragraph IV litigation typically concerns an ANDA applicant’s certification that an Orange Book-listed patent is invalid, unenforceable, or not infringed.[4] A device patent of this type would more commonly arise in separate patent litigation involving an implant manufacturer, drug-device combination sponsor, or medical-device supplier. What generic launch risks exist?There is no current generic-launch risk from this patent because it is expired. Commercial risks instead arise from:
For a modern entrant, the principal barrier would be development and regulatory execution, not U.S. exclusivity under Patent 5,292,515. Key Takeaways
FAQsCan a company sell a hydrogel implant that resembles the patented cartridge today?Yes, this patent no longer provides a live U.S. exclusion right. Separate unexpired patents must still be reviewed. Does claim 26 cover the drug inside the implant?No. Claim 26 covers the combination of the cartridge, polymer plug, and active agent. It does not independently claim the active agent as a chemical compound. Does the patent cover biodegradable implant polymers?No. The principal claims require a non-biodegradable polymer. Is an LHRH implant automatically covered by this patent?No. LHRH is only one claimed active-agent embodiment. The device must also satisfy the structural and polymer limitations. Does a nonuniform-wall cartridge avoid the patent?It would likely avoid claims requiring uniform wall thickness, but infringement analysis would still require review of each claim and any later patent in the relevant product family. References
More… ↓ |
Drugs Protected by US Patent 5,292,515
| Applicant | Tradename | Generic Name | Dosage | NDA | Approval Date | TE | Type | RLD | RS | Patent No. | Patent Expiration | Product | Substance | Delist Req. | Patented / Exclusive Use | Submissiondate |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| >Applicant | >Tradename | >Generic Name | >Dosage | >NDA | >Approval Date | >TE | >Type | >RLD | >RS | >Patent No. | >Patent Expiration | >Product | >Substance | >Delist Req. | >Patented / Exclusive Use | >Submissiondate |
Foreign Priority and PCT Information for Patent: 5,292,515
| Foriegn Application Priority Data | ||
| Foreign Country | Foreign Patent Number | Foreign Patent Date |
| 92 300394.1 | Oct 05, 1992 | |
International Family Members for US Patent 5,292,515
| Country | Patent Number | Estimated Expiration | Supplementary Protection Certificate | SPC Country | SPC Expiration |
|---|---|---|---|---|---|
| Austria | 149345 | ⤷ Start Trial | |||
| Australia | 1018392 | ⤷ Start Trial | |||
| Australia | 651654 | ⤷ Start Trial | |||
| Canada | 2059377 | ⤷ Start Trial | |||
| Germany | 69217900 | ⤷ Start Trial | |||
| Denmark | 0551698 | ⤷ Start Trial | |||
| European Patent Office | 0551698 | ⤷ Start Trial | |||
| >Country | >Patent Number | >Estimated Expiration | >Supplementary Protection Certificate | >SPC Country | >SPC Expiration |
