Metoprolol Fumarate and its Impurities

Metoprolol Fumarate, marketed under the tradename Lopressor among others, is a selective β1 receptor blocker medication. It is used to treat high blood pressure, chest pain due to poor blood flow to the heart, and a number of conditions involving an abnormally fast heart rate. Reference standards of Metoprolol Fumarate API, and its pharmacopeial, non pharmacopeial impurities, and stable isotopes are listed below.