Influence of food intake on plasma oxprenolol concentrations following oral administration of conventional and Oros preparations.

Plasma concentrations of oxprenolol have been measured in six healthy volunteers following single-dose oral administration of the drug in conventional and Oros dosage forms in fasting and postprandial states. After the Oros system, plasma concentrations reached peaks in most subjects at 3-8 h after dosing and were approximately 25% of those achieved with the conventional tablet. Plasma concentrations were well sustained for at least 24 h. A secondary peak occurred consistently at 12 h, possibly reflecting a transient change in clearance and/or distribution of the drug following the evening meal. With each formulation, plasma drug concentration profiles following administration in the fasting state did not differ significantly from those obtained when the drug was given postprandially. Drug absorption in vivo corresponded reasonably closely with in vitro drug release from the Oros system.