Invalidity dossier
US 6235224
Process for preparing microparticles through phase inversion phenomena
Current assignee: Brown University Research Foundation Inc
Added 9/23/2026, 4:25:14 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 6,235,224 B1
Title: Process for preparing microparticles through phase inversion phenomena
Patent number: US 6,235,224 B1
Application number: US09/442,723
Filing date: 1999-11-18
Publication/grant date: 2001-05-22
Prior art date: 1995-07-21 (listed as the priority date)
Original assignee / current assignee (as listed): Brown University Research Foundation Inc
Inventors: Edith Mathiowitz; Donald Chickering, III; Yong S. Jong; Jules S. Jacob
Legal status (as listed): Expired – Lifetime; anticipated expiration 2016-07-03
Purpose. The patent concerns a manufacturing process for making microparticles — referred to in the text as microspheres, microcapsules, nanospheres and nanoparticles — through phase inversion phenomena. The recurring terms in the supplied text (polymer, solvent, nonsolvent, spontaneous emulsification) indicate that polymer microparticles form when a polymer-containing phase is contacted with a nonsolvent, rather than requiring conventional emulsification equipment.
Plain-language scope. Based only on the supplied text, the process uses a polymer and a solvent, and contacting the polymer phase with a nonsolvent causes spontaneous formation of microparticles. Optional features mentioned include stirring, agitation, emulsification, and loading of a drug or other "core material"/"bioactive agent" into the particles. The disclosure names many possible materials, for example polylactic acid, polyanhydrides, polysiloxanes, polystyrene, polycaprolactone, zein, cellulose, and polyvinylpyrrolidone, along with solvents such as dichloromethane, diethyl ether, acetone, ethanol, hexane, toluene and water, and substances such as insulin, dicoumarol, salicylic acid, rhodamine B, DNA and plasmid. Application contexts mentioned include bioadhesive and delivery/transportation uses, and uptake via epithelium and Peyer's patch.
Source: https://patents.google.com/patent/US6235224/en
What the excerpt does not establish. The supplied text is metadata plus keyword-frequency fragments; it does not include the actual claim language, the written description, the abstract, references, or any legal conclusion. Accordingly, claim scope, claim count, dependencies, examples, and the legal significance of the listed dates or expiration status cannot be verified from this excerpt.
Generated 10/1/2026, 9:50:54 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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