Arotinolol

The stereospecificity of arotinolol is very important for its pharmacokinetic characteristics. Arotinolol is highly bound to serum proteins reaching a ratio of the original dose of 95.3% in the form of the R-enantiomer and 84.5% of the S-enantiomer. The presented stereospecificity is thought to be related to the α1-acid glycoprotein.

Preclinical studies showed a lack of intrinsic sympathomimetic activities or membrane-establishing properties. It is confirmed that arotinolol presents vasorelaxant activity. This characteristic is also proved to be mainly mediated by its α1-blocking property. In preclinical hypertension trials, there is a specific acute bradycardiac and antihypertensive activity with a pronounced reduction in heart rate. Some reports indicate a delayed development of hypertension when arotinolol is administered daily. Arotinolol has a dose-dependent decrease in cardiac contractility and coronary blood flow as well as an increase in total peripheral resistance. The effects of arotinolol have been confirmed in clinical trials where this drug was able to decrease cardiac index and thus, blood pressure.

Arotinolol binds to the β1-, β2- and α1- adrenergic receptor sites with a very high affinity. Radioligand studies have shown that arotinolol presents a higher affinity to the β-receptor compared to the α-receptor. The elucidated mechanism of action seems to be the result of a reduction in the cardiac output via the β-blockade and an additional inhibition of the counter-regulatory increase in peripheral resistance mediated by the α-blockade.

Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma.

Drugs that bind to but do not activate beta-adrenergic receptors thereby blocking the actions of beta-adrenergic agonists. Adrenergic beta-antagonists are used for treatment of hypertension, cardiac arrhythmias, angina pectoris, glaucoma, migraine headaches, and anxiety.

Arotinolol gets rapidly absorbed and distributed in the plasma. The plasma concentration peaks 2 hours after initial administration.

The stereospecificity of arotinolol is very important for its pharmacokinetic characteristics. Both of the enantiomers were found in urine, suggesting this as the major elimination pathway. It is possible to find arotinolol in urine 2-4 hours after initial administration.

The stereospecificity of arotinolol is very important for its pharmacokinetic characteristics. The S-enantiomer is highly retained in red blood cells. The distribution studies have shown that arotinolol is mainly distributed from the plasma to the liver followed by the lungs and lastly in the heart. The distribution in the liver was independent on the stereochemistry of the molecules.