Comparison of the pharmacodynamic and pharmacokinetic profiles of single and multiple doses of a commercial slow-release metoprolol formulation with a new Oros delivery system.

1 A new osmotic pressure mediated delivery system for metoprolol (Lopresor Oros) has been evaluated by measuring the haemodynamic effects and pharmacokinetics after single and multiple oral dosing in young healthy volunteers. 2 Similar studies have been carried out in the same group using equivalent single and multiple oral doses of the commercial slow-release preparation (Slow Lopresor). 3 The new osmotic delivery system produces a more uniform haemodynamic response: a plateau metoprolol concentration in plasma is reached about 6 h after dosing and is maintained for 10 h.