Invalidity dossier
US 6440458
Sustained release preparations
Current assignee: Astellas Pharma Inc
Added 9/23/2026, 9:46:17 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 — US 6,440,458 B1
Title: Sustained release preparations
Patent number: US6440458B1
Assignee/owner of record (per the supplied text): Original assignee Fujisawa Pharmaceutical Co., Ltd.; current assignee listed as Astellas Pharma Inc. (a 2005 reassignment to Astellas Pharma Inc., formerly Yamanouchi Pharmaceutical Co., Ltd., is shown). Assignors named on the 2000 assignment include Yamashita, Hashimoto, Nomura, Shimojo, Tamura, Hirose, Ueda, Saitoh, Ibuki, and Ideno.
Key dates: Priority date 1998-03-26; filing date 1999-03-25; publication/grant date 2002-08-27; anticipated expiration 2019-03-25. Legal status shown as "Expired – Lifetime."
Application number: US09/403,787.
Purpose and plain-language scope (drawn only from the supplied text): The patent concerns sustained-release (delayed-action) pharmaceutical preparations. The most frequently indexed subject matter in the excerpt is a formulation combining a sustained-release form with lactose, hydroxypropyl methyl cellulose, and a solid dispersion, with tacrolimus identified as a macrolide compound appearing repeatedly in the claims and description. Other indexed materials include ethyl cellulose, hydroxypropyl cellulose, dicalcium phosphate, and magnesium stearate; the excerpt also references the related compounds sirolimus and ascomycin, along with mention of water-insoluble and water-soluble polymers, fatty acids, glycerides, and solid solutions. Dissolution testing, particles, powders, granules, capsules, and tablets are also indexed. Because only a partial excerpt of the claims, abstract, and description was supplied, this overview does not restate specific claim language or numerical dissolution limits.
What the excerpted source does not establish: It does not provide verified claim text, the full specification, examples, or data; it does not establish validity, enforceability, inventorship conclusions, or claim scope as construed by any tribunal. The extract mentions litigation and family links, but those are not analyzed here per the stated rules. Chemical identifiers and index terms reflect automated indexing and may not match the operative claims.
Generated 10/1/2026, 9:34:02 PM
Cases on file (0)
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Litigation summary
Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.
Proceedings on file (0)
All PTAB activity →AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.
No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.