Invalidity dossier
US 5591767
Added 9/23/2026, 9:03:27 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5591767 A
Title: "Liquid reservoir transdermal patch for the administration of ketorolac"
Patent number / application: US 5591767 A; application US08/470,659, filed 1995-06-06.
Inventors: Judy M. Mohr, Richard W. Baker, Lisa A. Nakaji.
Assignee (per supplied text): Original assignee PharMetrix Corp; current assignee listed as NeurogesX Inc (the text cautions that listed assignees may be inaccurate and that no legal analysis is represented).
Key dates: Prior art date 1993-01-25 (the text calls this a priority-date assumption, not a legal conclusion); filed 1995-06-06; granted and published 1997-01-07; anticipated expiration 2014-01-07. Legal status: Expired – Fee Related.
Purpose: The patent concerns transdermal delivery of ketorolac (identified in the text as a drug compound for analgesic effect) using a liquid reservoir patch design. Keywords associated with the disclosure include skin, patch, ketorolac, enhancer, and plasticizing.
Plain-language scope (from the supplied text only): The excerpt indicates a patch that holds a liquid drug reservoir and delivers ketorolac through the skin. It references an enhancer (with fatty acid esters, fatty acids, and fatty alcohols appearing among described classes), a membrane (including microporous membrane), and an adhesive layer, with the drug diffusing across skin, including the stratum corneum. Ethanol and propylene glycol appear in the claims and description. Aqueous solutions, ketorolac tromethamine, glycerine, and fatty acid esters such as glyceryl monooleate are also mentioned. The excerpt notes controlled release, flux, permeation, and blood-level considerations.
Source: https://patents.google.com/patent/US5591767/en
What this excerpt does not establish: It does not provide the actual claim language, the written description, examples, or data. It does not establish the identity or contents of any prior-art reference, validity, infringement, enforceability, or the correctness of the listed assignees, priority date, or legal status. The text also flags litigation entries and reassignments, but these are not evaluated here.
Generated 10/1/2026, 9:40:59 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.