Purity >95%. (±)-Talinolol is a Beta1 -selective adrenoceptor antagonist well known for its cardioprotective and antihypertensive activity. By blocking Beta1 -adrenergic receptors, talinolol delays the conduction of stimuli in the AV node, reduces the sino-atrial conduction time, and impedes the sinus node automaticity. Because its metabolism in human liver microsomes is well understood, (±)-talinolol is useful for examining the activity of the drug-transporting MDR1 gene product P-glycoprotein.