Very low temperature casting of controlled release microspheres
US5019400A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 1989 |
| Grant date | May 28, 1991 |
| Priority date | — |
| Expiry date | May 1, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2989
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A process for preparing microspheres using very cold temperatures to freeze polymer-biologically active agent mixtures into polymeric microspheres with very high retention of biological activity and material. Polymer is dissolved in a solvent together with an active agent that can be either dissolved in the solvent or dispersed in the solvent in the form of microparticles. The polymer/active agent mixture is atomized into a vessel containing a liquid non-solvent, alone or frozen and overlayed with a liquified gas, at a temperature below the freezing point of the polymer/active agent solution. The cold liquified gas or liquid immediately freezes the polymer droplets. As the droplets and non-solvent for the polymer is warmed, the solvent in the droplets thaws and is extracted into the non-solvent, resulting in hardened microspheres.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.