Invalidity dossier
US 5120548
Swelling modulated polymeric drug delivery device
Current assignee: Merck Sharp & Dohme LLC
Added 9/23/2026, 8:29:03 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US5120548A
Title: Swelling modulated polymeric drug delivery device
Patent number: US5120548A | Application: US07/433,056 | Inventors: Gregory A. McClelland; Gaylen M. Zentner | Original assignee: Merck and Co Inc (current assignee listed as Merck Sharp and Dohme LLC) | Priority/filing date: 1989-11-07 | Publication (grant) date: 1992-06-09 | Legal status: Expired – Lifetime (anticipated expiration 2009-11-07)
Purpose: Swellable polymeric controlled release drug delivery devices can release drug at rates that vary with the environment of use — for example, gastrointestinal acidity — rather than being controlled by the dosage form, risking overdosing or underdosing. The patent addresses this by incorporating "controlled release swelling modulators" (buffers, osmagents, surfactants, or combinations) to regulate the degree of polymer swelling, and thus drug release, for a prolonged period, achieving constant or intermittent delivery. Rapid release elements may optionally modulate the start-up phase.
Plain-language scope: A core combines a beneficial agent, a swellable (usually water-swellable) polymer, and controlled release swelling modulators — the modulator either coated with a microporous wall or incorporated into individual matrices. The core may be (1) coated with an insoluble wall containing at least one exit means; (2) coated with an insoluble wall containing leachable pore-forming additives; or (3) uncoated. Variations include bilayered cores and laminates of semipermeable and microporous coats, optionally separated by a fluid-soluble layer. The polymer acts as a driving force expelling agent through holes or pores, or as a swellable matrix increasing permeability so agent diffuses out.
Source: https://patents.google.com/patent/[US5120548](/patent/US5120548)/en
What the excerpt does not establish: It does not provide claim language, the full specification, examples, or figures, so the precise metes and bounds of the claims cannot be determined from this text.
Generated 10/1/2026, 9:41:22 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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