Extraction , Isolation and Structure Elucidation of Digoxin

Introduction
Mechanism of Action
Pharmacokinetics
Indication
Administration
Contraindication and Precaution
Use cautiously in
Adverse Effects
Extraction and Isolation of Digoxin
CHEMICAL TESTS
Structure Elucidation

1. Extraction , Isolation and Structure Elucidation of Digoxin Prepared By: MOHAMMAD KHALID (Assistant Professor ) Krishna Pharmacy College, Bijnor (UP)

2. content Introduction Mechanism of Action Pharmacokinetics Indication Administration Contraindication and Precaution Use cautiously in Adverse Effects Extraction and Isolation of Digoxin CHEMICAL TESTS Structure Elucidation 09 May 2020 Krishna Pharmacy College, Bijnor 2

3. introduction It is a purified cardiac glycoside extracted from the foxglove plant, Digitalis lanata . Its corresponding aglycone is digoxigenin , and its acetyl derivative is acetyldigoxin . It is widely used in the treatment of various heart conditions namely atrial fibrillation, atrial flutter and sometimes heart failure that cannot be controlled by other medication. Pharmacological Class :- Cardiac Glycoside Therapeutic Class :- Inotrope, antiarrhythmic 09 May 2020 Krishna Pharmacy College, Bijnor 3

4. Mechanism of Action The main pharmacological effects of digoxin are on the heart. It has mechanical effects as it increases myocardial contractility; however, the duration of the contractile response is just slightly increased. Overall , the heart rate is decreased, while blood pressure increases as the stroke volume is increased, leading to increased tissue perfusion. Myocardial efficiency is due to improved hemodynamics, and the ventricular function curve is improved. 09 May 2020 Krishna Pharmacy College, Bijnor 4

5. Continue.... Other, electrical effects are an initial brief increase in action potential, followed by a decrease as the K+ conductance increases due to an increased intracellular amounts of Ca2+ ions. The refractory period of the atria and ventricles is decreased, while it increases in the sinoatrial and AV nodes. A less negative resting membrane potential is made, leading to increased excitability 09 May 2020 Krishna Pharmacy College, Bijnor 5

6. Continue.... Slight vasodilation is seen in heart failure. This effect is contrary to effects that should be seen as a result of increased intracellular calcium levels, but this occurs since digoxin improves hemodynamics, which leads to restored angiotensin levels and decreased sympathetic discharge, causing indirect vasodilation. It also affects the kidney by increased renal blood flow and increased glomerular filtration rate. A mild diuretic effect is seen only in heart failure . 09 May 2020 Krishna Pharmacy College, Bijnor 6

7. Pharmacokinetics About 70 to 80% of an oral dose of digoxin is absorbed, mainly in the proximal part of the small intestine. The degree of binding to serum albumin is 20 to 30%. Digoxin is extensively distributed in the tissues, as reflected by the large volume of distribution. High concentrations are found in the heart and kidneys, but the skeletal muscles form the largest digoxin storage. The half-life of elimination varies between 26 and 45 hours 09 May 2020 Krishna Pharmacy College, Bijnor 7

8. Continue.... The main route of elimination is renal excretion of digoxin, which is closely correlated with the glomerular filtration rate. In addition, some tubular secretion and perhaps tubular reabsorption occurs. Nearly all of the digoxin in the urine is excreted unchanged, with a small part as active metabolites. The clinical significance of dihydrodigoxin as a metabolite remains to be resolved. About 25 to 28% of digoxin is eliminated by nonrenal routes. Biliary excretion may rise up to 30% of a given dose, but the enterohepatic cycle seems to be of minor importance. 09 May 2020 Krishna Pharmacy College, Bijnor 8

9. Indication Heart Failure Tachyarrhythmias Atrial Fibrillation Atrial Flutter Paroximal atrial tachycardia 09 May 2020 Krishna Pharmacy College, Bijnor 9

10. Administration Administer slowly by direct IV injection over minimum of 5 minutes (longer if given undiluted) Do not administer if precipitate present Drug is severe skin irritant when given IV/IM and may cause severe local skin reaction with possible sloughing 09 May 2020 Krishna Pharmacy College, Bijnor 10

11. Contraindication and Precaution Hypersensitivity Uncontrolled Ventricular Arrhythmias AV block Constrictive Pericarditis Idiopathic Hypertrophic Subaortic Stenosis 09 May 2020 Krishna Pharmacy College, Bijnor 11

12. Use cautiously in Renal & Hepatic impairment Electrolyte imbalance Myocardial Infarction Thyroid Disoder Obesity Elderly Patient Pregnancy Breastfeeding infant 09 May 2020 Krishna Pharmacy College, Bijnor 12

13. Adverse Effects Dizziness Mental disturbances Diarrhea Headache Nausea Vomiting Maculopapular rash 09 May 2020 Krishna Pharmacy College, Bijnor 13

14. Extraction and Isolation of Digoxin 1. Initial Extraction & removal of Phenolic compound by precipitation: Extract 20 ml of powdered herb with 100 ml of ethanol 70% by warming on Hot Plate for 20 min Cool and filter or centrifuge to remove solid plant residue. To filtrate add 150 ml water & 20 ml strong solution of Lead Acetate, the Phenolic compound would ppt as insoluble lead. 09 May 2020 14

15. Centrifuge the mixture & pipette out & add 10% H 2 SO 4 drop wise until it precipitate forms. This treatment removes excess of lead ions as insoluble L ead Sulphate 09 May 2020 15

16. 2. Solvent partition to Remove C ardenolides from Aqueous Solution (i) Centrifuge the mixture & pipette off & extract with 50 ml CHCl 3 (ii) Wash with 20 ml water to remove any r esidual Lead ions (iii) Separate Chloroform extract & dry using anhydrous sodium Sulphate & Filter Chloroform into Round bottom Flask 09 May 2020 Krishna Pharmacy College, Bijnor 16

17. CHEMICAL TESTS Raymond test: A small quantity of glycoside is dissolved in 1ml of 50% ethanol followed by addition of 0.1 ml of 1% solution of dinitrobenzene in methanol. To this solution 2 – 3 drops of 20% sodium hydroxide solution is added. Appearance of violet color changes to blue color . Legal test : G lycoside + few drops of pyridine and 1 drop of 2% sodium nitroprusside and a drop of 20% NaOH is added. Deep red color occur Tollens test: M ixture of pyridine & ammonical silver nitrate gives silver mirror on wall of test tube . 09 May 2020 Krishna Pharmacy College, Bijnor 17

18. Continue…. Keller killani test: D rug + 10ml of 70% alcohol for few minute and filtered. To 5ml filtrate 10ml of hydrogen peroxide and 0.5 ml of strong solution of lead acetate is added. To this mixture 1 or 2 drop of concentrated sulphuric acid is added. Appearance of blue color confirms presence of deoxy sugar. Baljet test: S ection of digitalis + add sodium picrate solution yellow to orange color . Antimony trichloride test : S olution of glycoside is heated with antimony trichloride and trichloroacetic acid to obtain blue or violet color . 09 May 2020 Krishna Pharmacy College, Bijnor 18

19. Continue…. Liebermann test: S olution of glycoside in chloroform is added in acetic anhydride followed by conc. sulfuric acid gives violet to blue color. This test is for conformation of steroidal nucleus. Xanthohydral test: A red color is produced by deoxy sugar when they are heated with 0.125% solution of xanthohydral in glacial acetic acid . 09 May 2020 Krishna Pharmacy College, Bijnor 19

20. Structure Elucidation Molecular Formula: C 41 H 64 O 14 Molecular formula: Molecular Weight: 780.9 g/ mol Physical Description: Digoxin appears as clear to white crystals or white crystalline powder. Odorless. Used as a cardiotonic drug.  Taste: Bitter Melting Point: 249.3 °C (480.7 °F ) 09 May 2020 Krishna Pharmacy College, Bijnor 20

21. Digoxin 1. Sugar: Digoxin consist of three sugar residue ( glycone ) and non-carbohydrate aglycone moeity digoxigenin . The most commonly found sugar in cardiac glycosides are D-glucose, D- digitoxose , L- rhamnose & D- Cymarose . All aglycone represent similar set of Pharmacological action . Continue…. 09 May 2020 Krishna Pharmacy College, Bijnor 21

22. Continue…. It is the sugar moeity attached to the aglycone play an important role in governing Duration of Action, Partition Coefficient, Absolute Potency and Protein Binding properties of glycosides. It is also play an important role in inhibition enzyme induced metabolic change in the aglycone configuration. The presence of O-acetyl group on a sugar greatly affects the lipophillic characters and Pharmacokinetic of the entire glycosides. 09 May 2020 Krishna Pharmacy College, Bijnor 22

23. Continue…. 2. Aglycone : Aglycone portion of cardiac glycoside is a steroid nucleus with a unique set of Fused rings, which makes these agent easily distinguished from the steroids. Such ring Fusion gives the aglycone nucleus of Cardiac Glycosides the characteristic ‘U’ shape. Hydroxyl group are located at C - 3 site of the sugar attached and at C-14 position. The lactose ring at C-17 is another major stucture feature of cardiac glycosides Removal of sugar portion allows epimerization of the 3, 8 –OH group with decrease activity And increase toxicity due to change in polarity. The activity of compound depend to a great extent on position of 23 rd Carbonyl oxygen. 09 May 2020 Krishna Pharmacy College, Bijnor 23

24. Reference https:// www.slideshare.net/AmlendraYadav/digoxin-19788368 https:// www.webmd.com/drugs/2/drug-4358/digoxin-oral/details https:// www.drugs.com/digoxin.html https:// shodhganga.inflibnet.ac.in/bitstream/10603/62880/13/13_chapter%206.pdf https:// en.wikipedia.org/wiki/Digoxin https://www.slideshare.net/krishnatummala1/digoxin-and-gnsenosides https:// www.slideshare.net/NikhilVaishnav3/digitalis-nikku-ppt 09 May 2020 Krishna Pharmacy College, Bijnor 24

25. 09 May 2020 Krishna Pharmacy College, Bijnor 25

26. 09 May 2020 Krishna Pharmacy College, Bijnor 26