Controlled release vehicle
CA 2082496 A1 · Owner: Chang, An-Cheng · Inventors: Chang, An-Cheng; Wallach, Donald F. H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A new controlled release vehicle which acts by breakdown of the entrapping material upon hydration has been developed. The preferred release vehicle is made of a carboxylated cellulose, e.g. carboxymethylcellulose which, is treated with a cross-linking agent such as aluminum ions and, preferably, hydrophobicity agent such as acetic acid. The vehicle is broken down by a release agent e.g. cellulase, which may be coated on the vehicle together with a coating agent, e.g. hydroxypropylcellulose. The vehicle is dried, entrapping the molecule to be entrapped e.g. an, enzyme, and hydration activates the cellulase which breaks down the carboxymethylcellulose, releasing the entrapped molecule.
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 May 7, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 7, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 7, 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.
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.