The status of US patent application 17/344,217 (“Purification of sulfobutylated cyclodextrins with specific ion exchange resins” by CycloLab, Hungary) was changed on 11 January 2023: Notice of Allowance document was issued by USPTO (United States Patent and Trademark Office). The invention relates to a process to reduce butane sultone hydrolysis products (4-hydroxybutane-1-sulfonic acid, and bis(4-sulfobutyl) ether disodium) in sulfobutylether cyclodextrin reaction mixtures achieved with the combined use of a strong anion exchange resin having dialkyl 2-hydroxyethyl ammonium hydroxide functionality and a cation exchange resin. This process is hence differentiated from the already known separation methods utilized for the same purpose, i.e. ultrafiltration, diafiltration, centrifugation, extraction, solvent precipitation, and dialysis.
The new status means that the patent application will be granted within a couple of weeks. The examination procedure was exceptionally short, since not even two years have passed since the filing date.
The application to be granted can be accessed here: