| 摘要 |
<p>Methods are provided for the synthesis of synthetic polymeric delivery systems consisting of microparticles which contain a diagnostic imaging agent using spray drying of dilute synthetic polymer solutions, typically between 0.2 and 20 w/v% polymer. In a preferred embodiment, the imaging agent is a gas, the polymer is biodegradable, the polymer solution is saturated with gas and formed into an emulsion, then spray dried. Microparticles produced by this method typically have an average diameter of between about one to seven microns, and therefore freely pass through the pulmonary capillaries. Additional, or alternative, imaging agents can be incorporated within the microparticles. Larger microparticles can also be manufactured for administration to mucosal membranes or oral administration. Adhesion of these microparticles can be enhanced through the selection of bioadhesive polymers. Targeting can also be achieved by selection of the polymer or incorporation within or coupling to the polymer of ligands which specifically bind to particular tissue types or cell surface molecules. Additionally, ligands may be attached to the microspheres which affect the charge, lipophilicity or hydrophilicity of the particle. The polymeric microparticles are useful in a variety of diagnostic imaging procedures including ultrasound imaging, magnetic resonance imaging, fluoroscopy, X-ray, and computerized tomography. The microspheres may be used in a variety of imaging applications including cardiology applications, as well as for organ and peripheral vein imaging.</p> |
