Use of specific counteranions to modify the solubility of tetrazolium salts
CA 2084036 C · Owner: Bayer Corporation · Inventors: Hatch, Robert P.; Blatt, Joel M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to sulfonate and phosphonate salts of tetrazolium compounds wherein the anion X.theta.is represented by the formula: (see formula I), wherein R is an organic radical suitable for increasing the solubility of the tetrazolium salt in an aqueous or polar non-aqueous solvent, and the tetrazolium salt is represented by the formula:, (see formula II) wherein X.theta. is the anion, R1 and R2 are phenyl groups and R3 is phenyl or 2-thiazolyl wherein the phenyl groups are unsubstituted or substituted as represented by the formula:, (see formula III), wherein the Y groups which can be the same or different, are alkoxy aryloxy, alkyl, amido, alkylamido;, arylamido alkylthio, …
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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 27, 1992 and granted February 20, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 27, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 27, 2014.
- 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
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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.