Zotarolimus, also known as ABT-578 and A-179578, is an immunosuppressant. It is a semi-synthetic derivative of rapamycin. It was designed for use in stents with phosphorylcholine as a carrier. Coronary stents reduce early complications and improve late clinical outcomes in patients needing interventional cardiology. Medtronic are using zotarolimus as the anti-proliferative agent in the polymer coating of their Endeavor and Resolute products.