Novel vitamin D3 derivatives, processes for preparation thereof, and antigens comprising said derivatives to be used for preparation of antibodies for immunochemical assay and antibodies prepared therefrom

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Listed from its EPO record in Patent Yard's archive of European patents past their term. Its claims, description and drawings are in the EPO PDF and on Google Patents, and the Claude kit works from them.

Why it's free to use

• Filed April 20, 1982 and granted October 30, 1985. A European patent lasts at most 20 years from filing, so its term ended April 20, 2002.
• A supplementary protection certificate, which can extend a medicine or crop-protection patent, adds at most five and a half years, so even that would have ended by October 20, 2007.
• We check European rights only. A US or other national patent in its family could still be in force: check its family on Espacenet or Google Patents.