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Expired Canadian patentCanada

2-thiazolyl tetrazolium salt indicators

CA 2049237 C · Owner: Beck, Gunther · Inventors: Kocher, Jurgen; Beck, Gunther; Wehling, Klaus

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

2-Thiazolyl tetrazolium salt compounds characterized by a reflectance spectrum exhibiting an extended plateau above about 600-650 nm. Such compounds are useful as chromogenic indicators for reducing substances such as NADH. The reflectance plateau confers improved accuracy to analytical assays, particularly for the determination of analytes of medical diagnostic significance in, which a colorimetric response on a reagent carrier matrix is measured by reflectance.

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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 August 15, 1991 and granted October 19, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 15, 2011.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 15, 2013.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledAugust 15, 1991
GrantedOctober 19, 1999
Term endedAugust 15, 2011
Patent numberCA 2049237 C
Classification (IPC)C07D417/04 +2 more

Timeline

Timeline From CIPO dates

1992199419961998200020022004200620082010Application filedAug 15, 1991Patent grantedOct 19, 1999Term endedAug 15, 2011

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.