Potent β-adrenoceptor and α1-adrenoceptor antagonist (Ki values are 0.81, 0.96 and 2.2 nM for β1-, β2- and α1-adrenoceptors respectively) that displays antihypertensive and peripheral vasodilatory activity. Blocks cardiac inward-rectifier K+ (KIR) channels, voltage-dependent Ca2+ channels and exhibits antioxidant properties at higher concentrations. Purity 99%. MW (observed): 406.47