System for controlled release of biologically active compounds
US4933185A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 11, 1988 |
| Grant date | Jun 12, 1990 |
| Priority date | — |
| Expiry date | Jul 11, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2985
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A controlled release system for delivery of a biologically-active substance. In one embodiment, there is a delayed release of a biologically-active substance. In a second embodiment, the delayed release is preceded by an initial release of biologically active substance. In other variations of the system, there are mulitple discrete releases over time or a continuous slow release combined with discrete releases. The delayed exposure is achieved through the design and construction of the system, specifically, formation of ionically-coated microcapsules around the biologically-active substance in conjunction with a microcapsule core-degrading enzyme. Release of active substance takes place in a burst at such a time as the core degrading enzyme has reduced the core to a molecular weight too low to support enough interaction with the cationic skin to maintain its integrity as a skin. In one example, microcapsules are formed of an ionically cross-linked polysaccharide, calcium alginate, which is further ionically coated with a poly-cationic skin of poly-L-lysine. The capsule coating serves a dual purpose: to control diffusion of the biologically-active substance and the core-degrading en…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.