Biodegradable high-molecular polymers, production and use therof
CA 2040141 C · Owner: Yamada, Minoru · Inventors: Yamada, Minoru; Ogawa, Yasuaki; Heya, Toshiro
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention provides a method of purifying biodegradable aliphatic polyesters which comprises dissolving, in a readily water-soluble organic solvent a biodegradable aliphatic polyester which contains lowmolecular substances and adding water to the resulting solution to thereby remove said low-molecular substances, biodegradable aliphatic polyesters obtained by said method and containing low-molecular substances with a molecular weight of 1,000 or less in an amount of not higher than 3%, and drug-containing compositions which comprise any of said biodegradable polyesters.
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 April 10, 1991 and granted May 14, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 10, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 10, 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.