Olprinone Hydrochloride, also known as Loprinone, is a phosphodiesterase (PDE) 3 potent inhibitor, exhibiting IC50 values of 150, 100, 0.35, and 14 uM for PDE1, PDE2, PDE3, and PDE4, respectively. It is utilized in heart failure research for its positive inotropic and vasodilative properties. It also exhibits anti-inflammatory activity (1) (2).