Separation of the enantiomers of amlodipine via their diastereomeric tartrates
CA 2186263 C · Owner: Pfizer Limited · Inventors: Spargo, Peter Lionel
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for the separation of R-(+)- and S-(-)-isomers of amlodipine (I) from mixtures thereof which comprises the reaction of, the mixture of isomers with either L- or D-tartaric acid in an organic solvent containing sufficient dimethyl sulphoxide (DMSO) for the precipitation of, respectively, a DMSO solvate of an L-tartrate salt of R-(+)-amlodipine or a DMSO solvate of a D-tartrate salt of S-(-)amlodipine.
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 March 6, 1995 and granted May 11, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 6, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 6, 2017.
- 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.