Polysiloxane-polyurethanes and contact lenses thereof
CA 2001969 C · Owner: Ciba Specialty Chemicals Holding Inc. · Inventors: Harisiades, Paul
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A novel polysiloxane polyurethane is described which is obtained by reaction of an isocyanate capped polysiloxane prepolymer with a polysiloxane-disilanol and which contains O-silyl-urethane linkages. The novel polysiloxane-poly-urethanes are useful as oxygen permeable membranes or films as bandages and drug carriers, for example in transdermal drug delivery, and especially as highly oxygen permeable soft, contact lenses.
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 November 1, 1989 and granted May 30, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 1, 2009.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 1, 2011.
- 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.