Abstract: The present invention relates to novel microparticles formed using a coacervation process, methods of forming the microparticles, and methods of using the microparticles for the sustained release administration of therapeutic agents.

Abstract: Methods and apparatus are disclosed for coating endoprostheses. The methods use distributive forces such as centrifugal force or vibration to distribute a bioactive liquid over the surface of the endoprosthesis. In some embodiments, the endoprosthesis is elongated along the longitudinal axis, and is substantially tubular, such as a stent. In other embodiments, the force is applied by rotating the endoprosthesis at speeds between 100-100,000 RPM, or by vibrating it at frequencies between about 10 Hz and about 200,000 Hz. The invention also includes a device for providing a predictable coating on the surface of an endoprosthesis, which includes means for applying bioactive liquid to the endoprosthesis, and means for applying centrifugal force or vibration to distribute the bioactive liquid. The invention also includes endoprostheses that have been subjected to centrifugal force to distribute a bioactive liquid coating layer.