Metoprolol |
Metoprolol is a selective beta1 receptor blocker used in treatment of several diseases
of the cardiovascular system, especially hypertension. It is marketed under
the brand name Lopressor or Lopresor, respectively, by Novartis, and Toprol-XL
(in the USA); Selokeen (in Nederlands); as Minax by Alphapharm (in Australia),
Metrol by Arrow Pharmaceuticals (in Australia), as Betaloc by AstraZeneca, as
Neobloc by Unipharm (in Israel) and as Corvitol by Berlin-Chemie AG. A number
of generic products is available, too. The active substance metoprolol is employed
either as metoprolol succinate or metoprolol tartrate (whereas 100 mg metoprolol
tartrate corresponds to 95 mg metoprolol succinate), as conventional release-
or prolonged-release formulation. Physical properties Metoprolol is very low melting. Its melting point is around 45 degrees Celsius (as determined by Differential scanning calorimetry). For this reason metoprolol is always manufactured in salt form, as drugs with melting points below 100 degrees Celsius are difficult to work with in a manufacturing environment. The free base exists as a waxy white solid, where the tartrate salt is finer crystalline material. |