Class (24) Beta Adrenergic Receptor Blockers | Medicinal Chemistry 01 | Beta Blocker | B.Pharma 4th

Download the "Solution Pharmacy" Mobile App to Get All Uploaded Notes, Model Question Papers, Answer Papers, Online Tests and other GPAT Materials - https://play.google.com/store/apps/de... Solution Pharmacy will cover this syllabus of medicinal chemistry 01 for B.Pharmacy 4th semester Unit 02 – (01) Drug acting on the autonomic nervous system (02) Adrenergic neurotransmitters – biosynthesis and catabolism of catecholamine, adrenergic receptors, alpha-adrenergic receptor and beta-adrenergic receptor and the distribution of alpha and beta-adrenergic receptors (03) Sympathomimetic agents structure-activity relation (SAR) of sympathomimetic agents like direct acting – Nor-epinephrine, epinephrine, Phenylephrine, dopamine, methyldopa, clonidine, dobutamine, isoproterenol, terbutaline, salbutamol, bitolterol, naphazoline, oxymetazoline, and xylometazoline. (04) Indirect-acting agents – Hydroxy amphetamine, Pseudoephedrine, propylhexedrine, (05) Agents with a mixed mechanism (06) Adrenergic antagonist – (07) Alpha adrenergic blocker, tolazoline, Phentolamine, Phenoxybenzamine, prazosin, dihydroergotamine, mtyhlesergide. (08) Beta-adrenergic blockers – SAR of beta blockers, Propranolol, Metipranolol, Atenolol, Bisoprolol, esmolol, metoprolol, labetalol, carvedilol Beta-Adrenergic blockers Beta - blockers are among the most widely employed antihypertensive and are also considered the first line treatment for glaucoma. Most of the B-blockers are in the chemical class of aryloxypropanolamines. The first B- blocker, dichloroisoproterenol was reported in 1958. Dichloroisoproterenol SAR of Beta-blocker 1. Dichloroisoproterenol differs from isoproterenol in that the agonist directing 3'4-diOH groups have been replaced by two chloro groups but DC1 is not a pure antagonist but partial agonist. 2. Propranolol is the standard against which all other B-blockers compared. It consists of OCH2 group which incorporated between the aromatic ring & the ethylamine side chain 3. OCH2 group is responsible for the antagonistic property of the molecules. However it is not true because several compounds contain - OCH2 group are potent Beta-agonist. 4. The aryl group also affects the absorption, excretion & metabolism of B-blockers. 5. The nature of the aromatic ring is also a determinant in their Beta 1 selectivity. Non Selective blockers Propranolol Mechanism of action It is prototypical & non selective p-blockers. It blocks the beta 1 & Beta 2 receptors with equal affinity SAR 1. Lengthening of side chain prevent appropriate binding of required functional group to same receptor site 2. Propranolol is the most lipophilic drug among the available B-blockers. Metabolism: It undergoes extensive first-pass metabolism one of the major metabolite of propranolol is mephthoxylactic acid. It is formed by metabolic reactions involving N- dealkylation, deamination & oxidation of the resultant aldehyde. Therapeutic uses: Propranolol approved for use in angina pectoris, past myocardia infarction, hypertension, cardiac, migraine prophylaxis & essential tremor also used in CNS disorders. Atenolol Mechanism of action It is a type of selective B1 receptors antagonist, a drug belonging to the group of ß blocker used in treatment of cardiovascular diseases & hypertension. Metabolism: Atenolol undergoes little or no metabolism by the liver and the absorbed portion is eliminated by renal excretion Over 85% of intravenous dose is excreted in urine within 24 hours compared with 50% for an oral dose. Therapeutic uses: Atenolol is used for a number of conditions including hypertension, angina, long QT syndrome, acute myocardial infarction, supraventricular tachycardia, ventricular tachycardia, and the symptoms of alcohol withdrawal. Metoprolol Mechanism of action Metoprolol blocks Beta 1 adrenergic receptors in heart muscle cells, thereby decreasing the slope of phase 4 in the nodal action potential (reducing Na+ uptake) and prolonging repolarization of phase 3 (slowing down K+ release). It also suppresses the norepinephrine-induced increase in the sarcoplasmic reticulum (SR) Ca2+ leak and the spontaneous SR Ca2+ release, which are the major triggers for atrial fibrillation SAR The presence of para substitute of sufficient size on the aromatic ring along with absence of Meta substitute is one of the common structural features of Beta 1-adrenoreceptor antagonist. E-Mail for official and other work - solutionpharmacy@gmail.com #solutionpharmacy #Pharmacologyclass #Pharmacognosyvideos #GPAT