PH-sensitive coatings based on cellulose acetoacetate
US5811121A · kind A · utility
9Cited by
16References
18Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1997 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Jan 29, 2017 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61K9/2866
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
This invention is based on the discovery that certain cellulose acetoacetate mixed esters will remain insoluble in mild (near-neutral) or acidic aqueous solutions, but dissolve under alkaline conditions. The esters are particularly useful as coatings for controlled-release applications. Coatings comprising these esters will dissolve to release a coated active agent under alkaline conditions, the exact pH at which dissolution occurs being adjustable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.