Method for the resolution of folinic acid
CA 2002430 C · Owner: Muerdel, Guenter · Inventors: Conti, Josef; Ulmann, Martin; Mueller, Hans Rudolf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is provided for separating diastereomers of (6R,S)-folinates. The process includes adding a sufficient amount of a water-soluble alkali metal salt of an inorganic acid or of an organic acid or a water-soluble ammonium salt of an inorganic acid or of an organic acid to an aqueous starting solution of an alkali metal salt of (6R,S)-folinic acid or an alkaline earth metal salt of (6R,S)-folinic acid at a neutral pH to precipitate the (6R)-folinate. The resultant (6R)-folinate precipitate is then separated off. The (6S)-folinate is then isolated from the filtrate.
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 November 7, 1989 and granted March 4, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 7, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 7, 2011.
- 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.