Stable ascorbic acid compositions
CA 2054189 C · Owner: Darr, Douglas · Inventors: Pinnell, Sheldon R.; Darr, Douglas
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A stable topical composition consists essentially of at least about 1 wt.% Lascobic acid, preferably from about 3 to 20 wt. % L-ascorbic acid and more preferably about 5 to 10 wt% L-ascorbic acid in water and a carrier for topical application is disclosed. Such a composition appears to allow ready penetration into the skin and retards the damage caused by ultraviolet tight. Any composition containing at least about 1 wt. % L-ascorbic acid is expected to have beneficial effects, with the concentration of L-ascorbic acid being primarily limited by its solubility in the water/carrier system. The ratio of water to carrier is at least 1:1 and more preferably from 2:1 to 10:1, and the pH of …
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 16, 1990 and granted November 21, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 16, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 16, 2012.
- 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.