Adaprolol maleate

Adaprolol maleate is a new beta-adrenergic antagonist that is being developed to treat glaucoma. The soft drug was designed to minimize systemic activity through facile inactivation to an inactive metabolite. Studies with other potent beta-adrenergic antagonists indicated that tissue specific receptor differences might be more stringent for selected beta-adrenergic blocking activities and suggested that R enantiomers of traditional beta-blockers should be developed for controlling glaucoma. The present studies demonstrate that the potent ocular hypotensive effects of adaprolol are not stereoselective. In contrast, cardiac effects could be detected after intravenous S(+) adaprolol, but not R(-) adaprolol. The studies confirm that adaprolol functions as a potent beta-adrenergic antagonist. The negligible systemic beta-blocking activity detected with opthalmic administration of adaprolol is consistent with soft drug design.

Adaprolol maleate (adaprolol) is a new beta-adrenergic receptor blocker. The cardiac electrophysiologic characteristics and the duration of action of adaprolol were studied in intact anesthetized dogs. The electrophysiologic parameters were evaluated before drug administration and 10 min after the administration of maintenance infusion of adaprolol (N = 5). The duration of action was measured during constant infusion of isoproterenol, giving the adaprolol as a single i.v. bolus in different concentrations (N = 5). Results of this study showed that adaprolol has marked electrophysiologic effects. Its major action was on sinus node; it prolonged the basic sinus cycle length and had significant effect on intrinsic automaticity as reflected by the prolonged corrected sinus node recovery time and sinuatrial conduction time. There was, also, direct effect on atrial function and AV nodal function. Adaprolol prolonged the effective refractory period of the His-Purkinje system and the ventricle. The onset of action was very rapid (within seconds) and the duration of action was relatively prolonged (3 hrs). The potency of adaprolol's electrophysiologic effects are higher compared to other widely used beta-blockers. Adaprolol appears to be a potent beta-blocker with particularly strong antiarrhythmic effect and it would be very useful in the treatment of both supraventricular and ventricular tachyarrhythmias and ectopic beats.