Process for preparing aqueous chitosan solutions and gels
CA 2134635 A1 · Owner: Merck Patent Gesellschaft Mit Beschraenkter Haftung · Inventors: Nies, Berthold
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a process for preparing aqueous solutions and gels of chitosan in which chitosan, and an acid chelating agent are dissolved in water. Such solutions can have their viscosity drastically increased or be converted into high-viscosity gels, by adding salts of polyvalent metals and acids in which chitosan is only moderately soluble or insoluble. From such solutions salt-like chitosan-chelating, agent adducts can be obtained by removal of water or by precipitation using an organic solvent.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 28, 1994. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended October 28, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 28, 2016.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.