Active agent containing hydrogel devices wherein the active agent concentration profile contains a sigmoidal concentration gradient for improved constant release, their manufacture and use
US4624848A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 10, 1984 |
| Grant date | Nov 25, 1986 |
| Priority date | — |
| Expiry date | May 10, 2004 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61K9/2027
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.