| abstract |
PCT No. PCT/EP92/01327 Sec. 371 Date Dec. 23, 1993 Sec. 102(e) Date Dec. 23, 1993 PCT Filed Jun. 3, 1992 PCT Pub. No. WO92/21382 PCT Pub. Date Dec. 10, 1992This invention relates to ultrasound contrast agents in the form of microparticles comprising a biotolerable matrix (e.g. of a carbohydrate or an X-ray contrast agent) in association with a gas or a precursor therefor. The contrast agents are stabilized to enhance their in vivo stability and/or echogenicity by covalently modifying the structure of the matrix, e.g. to introduce crosslinking groups or to attach lipophilic groups and/or molecules. The covalent moieties may include biodegradable linkages to assist rapid subsequent elimination of the contrast agents from the system. |