The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 25, 1986
Filed:
May. 10, 1984
Ping I Lee, Berwyn, PA (US);
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
An active agent containing controlled release diffusion device comprising a swellable hydrogel matrix in the non-swollen state, interpenetrated with an active agent solute having a stable concentration distribution increasing in a gradient normal to the surface of the device and between the surface and the core thereof, said gradient being in the form of a substantially continuous, inflection point containing, sigmoidal curve, such that the device, when placed in an aqueous hydrogel swelling environment, releases said active agent in a controlled continuous manner by diffusion for a predetermined period of time, a method of preparing such a device, and the use thereof to release an active agent into the intended environment of use.