Polymeric Controlled Release of Cardiovascular Drugs

Controlled release drug-polymer implants have been useful for a variety of cardiovascular disease processes. Implanting a controlled release system at the site of a pathologic focus results in regional drug administration being optimized and the chance for systemic side effects greatly reduced. The general formulations, which have been useful, include nondegradable polymers such as silicone rubbers, polyurethanes, and ethylene:(vinyl acetate). In addition, biodegradable matrices composed of compounds such as high molecular weight polyanhydrides have also been valuable. These polymers may be combined with dispersed or dissolved drugs to form matrix systems, which release contained agents based on either diffusion or biodegradation or both. Furthermore, reservoir configured controlled release systems, with rate limiting membranes and refilling capability, also represent an important therapeutic advantage. Controlled release systems have been demonstrated by our group to be advantageous for the therapy of ventricular arrhythmias, cardiovascular calcification, and prevention of cardiac transplantation rejection. In addition, the work of others has demonstrated controlled release implants to be valuable for preventing prosthetic valve endocarditis and for preserving pacemaker lead electrical function. Future controlled release systems will be based on unique agents, advanced reservoir systems, and feedback-modulation capabilities.