Invalidity dossier
US 4810646
Glucan compositions and process for preparation thereof
Current assignee: Massachusetts Institute of Technology
Added 9/21/2026, 9:36:05 AM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US4810646A
Title: "Glucan compositions and process for preparation thereof"
Patent number / application: US4810646A; application US06/675,927
Inventors: Spiros Jamas, ChoKyun Rha, Anthony J. Sinskey
Original assignee: Massachusetts Institute of Technology. The source also lists current assignees as Massachusetts Institute of Technology and Biopolymer Engineering Inc., noting Google "has not performed a legal analysis" and makes no warranty as to accuracy of that list.
Key dates: Priority/filing date 1984-11-28; publication (grant) date 1989-03-07; anticipated expiration 2006-03-07. Legal status listed as "Expired - Lifetime" (expressly an assumption, not a legal conclusion).
Subject matter (from the supplied text): The patent concerns glucan (a polysaccharide) compositions and a process for preparing them. The indexed terms indicate the disclosure involves Saccharomyces cerevisiae (including strain A364A) cultured in a growth medium, harvested yeast cells, and a cell-wall/matrix material treated with hydroxide (sodium hydroxide) and/or acetic acid, with steps such as extraction, centrifugation, enzymatic treatment (cellulases), acid treatment, drying and packing. The abstract-level terms reference whole glucan particles, viscosity, an aqueous suspension, and uses as a thickening agent and stabilizer; cellulase and other enzymatic degradation steps appear in the description, as does the bacterium Candida albicans extract among reagents.
Plain-language scope: In essence, the document describes obtaining glucan from yeast, breaking down the cells and separating the glucan, and using the resulting glucan as a material that thickens or stabilizes aqueous formulations. The supplied excerpt does not include the actual claim language, so the precise scope of the monopoly granted cannot be stated from it.
Source: https://patents.google.com/patent/[US4810646](/patent/US4810646)/en
What the excerpt does not establish: The excerpt does not reproduce the claims, the full description, any prior-art references or citations, prosecution history, or any determination of validity, enforceability, or infringement. Later reassignments/security interests appearing in the text are shown only as recorded entries and were not analyzed here.
Generated 10/1/2026, 10:02:03 PM
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Litigation summary
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Proceedings on file (0)
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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.