Antianginal Drugs: A Medicinal Chemistry Perspective
Introduction to Antianginal Drugs
Definition and therapeutic goals
Pathophysiology of angina pectoris
Major classes of antianginal drugs
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Nitrates
Chemical structure: Organic nitrates (R-ONO2)
SAR: Importance of nitrate group for activity
Mechanism: NO release 鈫?cGMP activation 鈫?vasodilation
Examples: Nitroglycerin, Isosorbide dinitrate, Isosorbide mononitrate
Metabolism: Enzymatic reduction to nitric oxide
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Beta-Blockers
General structure: Aryloxypropanolamine
SAR: Importance of 尾-phenethylamine moiety
Selectivity: 尾1 vs. 尾2 receptor binding
Examples: Propranolol (non-selective), Metoprolol (尾1-selective)
Metabolism: Hepatic, often via CYP2D6
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Calcium Channel Blockers
Subclasses: Dihydropyridines, Benzothiazepines, Phenylalkylamines
SAR: Importance of heterocyclic ring systems
Mechanism: L-type calcium channel blockade
Examples: Amlodipine (DHP), Diltiazem (BZT), Verapamil (PAA)
Metabolism: Hepatic, often via CYP3A4
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Ranolazine
Chemical structure: Piperazine derivative
SAR: Importance of aromatic rings and piperazine core
Mechanism: Late sodium current inhibition
Metabolism: Hepatic, primarily via CYP3A4
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Ivabradine
Chemical structure: Benzocyclobutane derivative
SAR: Importance of lactam ring for If channel binding
Mechanism: Selective If current inhibition in SA node
Metabolism: Hepatic, primarily via CYP3A4
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Trimetazidine
Chemical structure: Piperazine derivative
SAR: Importance of methoxy groups for activity
Mechanism: Inhibition of long-chain 3-ketoacyl-CoA thiolase
Metabolism: Renal excretion, minimal hepatic metabolism
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Structure-Activity Relationships (SAR)
Key pharmacophores for each drug class
Modifications affecting potency and selectivity
Importance of stereochemistry in antianginal drugs
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Drug-Receptor Interactions
Binding sites for nitrates, beta-blockers, and CCBs
Molecular basis for drug selectivity
Role of allosteric modulation in antianginal drug action
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Pharmacokinetics and Drug Metabolism
Absorption and distribution characteristics