Microspheres comprising polymer and drug dispersed there within
US5718921A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 2, 1996 |
| Grant date | Feb 17, 1998 |
| Priority date | — |
| Expiry date | Aug 2, 2016 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61K9/5031
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
A method for preparation of biodegradable polymeric drug delivery devices using relatively low temperatures and non-aqueous solutions which is particularly useful with polyanhydrides, thermolabile drugs, and in forming multi-layered devices. In a first embodiment, the polymer is dissolved in a volatile organic solvent, the drug is dispersed or dissolved in the polymer solution, the mixture is suspended in an organic oil, and the organic solvent is extracted into the oil, creating microspheres. The preferred polymers are polyanhydrides since they are biodegradable and have been proven to be useful in vivo. In a second embodiment, the polymer is dissolved in organic solvent with or without the drug, and the mixture is suspended in glycerol. The suspension is frozen and the organic solvent slowly evaporated. Using these embodiments, alone or in combination with other methods including the "hot melt" technique, multi-walled microspheres having each wall degrading at a different rate or containing different drugs can be manufactured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.