Method for enhancing the echogenicity and decreasing the attenuation of microencapsulated gases
US6045777A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 1997 |
| Grant date | Apr 4, 2000 |
| Priority date | — |
| Expiry date | Jun 30, 2017 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61K49/223
- WIPO fieldPharmaceuticals
- WIPO sectorChemistry
Abstract
It has been discovered microparticles formed from natural or synthetic polymer with thicker walls have significantly enhanced echogenicity as compared with microparticles having thinner walls. The effect of wall thickness has been determined experimentally as well as inserted into a formula for use in predicting the optimum conditions. In the preferred embodiment, the polymers are synthetic biodegradable polymers and the wall thickness is between about 100 and 660 nm, although wall thicknesses from about 20 nm to in excess of 500 nm can be used. 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, polylactide or polyglycolide, most preferably conjugated to polyethylene glycol or other materials inhibiting uptake by the reticuloendothelial system (RES). The microspheres may be used in a variety of ultrasound imaging applications including cardiol…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.