Polymer-lipid microencapsulated gases for use as imaging agents
US5837221A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1996 |
| Grant date | Nov 17, 1998 |
| Priority date | — |
| Expiry date | Jul 29, 2016 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61K49/223
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
It has been discovered that the incorporation of gases, especially fluorinated gases such as perfluorocarbons, into microparticles formed from the combination of a natural or synthetic polymer and lipid have significantly enhanced echogenicity as compared with microparticles not including the lipid. Compounds other than lipids which are hydrophobic and limit the penetration and/or uptake of water into the microparticles can also be incorporated into the microparticles to enhance echogenicity. In the preferred embodiment, the polymers are synthetic biodegradable polymers. The microparticles are manufactured with a diameter suitable for the targeted tissue to be imaged, for example, with a diameter of between 0.5 and 8 microns for intravascular administration, and a diameter of between 0.5 and 5 mm for oral administration for imaging of the gastrointestinal tract or other lumens. Preferred polymers are polyhydroxy acids such as polylactic acid-co-glycolic acid, most preferably conjugated to polyethylene glycol or other materials inhibiting uptake by the reticuloendothelial system (RES). The most preferred lipids are phospholipids, preferably dipalmitoylphosphatidylcholine (DPPC), dis…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.