Inhibitor of HMG-CoA reductase; decreases cholesterol biosynthesis, in vitro and in vivo. Induces apoptosis, arrests cancer cells in G1 phase and downregulates cdk 2, 4, and 6, cyclin D1 and E1, p21 and p27. Inactive lactam prodrug of mevastatin hydroxy acid, naturally bioactivated in vivo following oral administration. Purity 98%. MW (observed): 390.52