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Premium member Presentation Transcript MACROLIDES : M A C R O L I D E S THIS PPT IS CONTRIBUTED BY SAIKUMAR 1 REVOLUTIONPHARMD.COMINTRODUCTION:: INTRODUCTION: Macrolide antibiotics are so named as they possess a macrocyclic lactone usually having 12 to 17 atoms SOURCE: These are produced by streptomyces species and the products of actinomycetes 2 REVOLUTIONPHARMD.COMCommon Structural Features:: Common Structural Features: 5 common chemical features they are A macro cyclic lactone, usually having 12 to 17 atoms A ketone group 3 REVOLUTIONPHARMD.COMPowerPoint Presentation: One or two aminosugars linked to the nucleus. A Neutral sugar linked either to amino sugar or to lactone ring The presence of the dimethyl amino moiety on the sugar residue, which explains the basicity of these compounds and consequently formation salts. 4 REVOLUTIONPHARMD.COMSPECTRUM OF ACTIVITY:: SPECTRUM OF ACTIVITY: active against most species of gram They are generally (+) bacteria both cocci and bacilli . The antibacterial spectrum of activity of the more potent macrolides resembles that of pencillin. They also exhibit useful effectiveness against gram (-) cocci, specially Neisseria Species 5 REVOLUTIONPHARMD.COMMECHANISM OF ACTION:: MECHANISM OF ACTION: 6 REVOLUTIONPHARMD.COMPHYSICAL PROPERTIES:: PHYSICAL PROPERTIES: Occurs as crystalline powders. Water insoluble molecules. stable in aqueous solutions at or below room temperature. Unstable in acidic conditions and forms internal cyclic ketal. 7 REVOLUTIONPHARMD.COMCHEMICAL PROPERTIES: : CHEMICAL PROPERTIES: Macrolides are stable in aqueous solutions at or below room temperature. Macrolides are unstable under acidic conditions &undergo an intramolecular reactions to form an inactive cyclic ketone . 8 REVOLUTIONPHARMD.COMChemical Instability Of Macrolides:: Chemical Instability Of Macrolides: 9 REVOLUTIONPHARMD.COMSTRUCTURAL ACTIVITY RELATIONSHIP: STRUCTURAL ACTIVITY RELATIONSHIP As macrolide are unstable in acidic pH,a no. of strategies have been utilised to improve the acidic stability of erythromycin. The addition of hydroxylamine to the ketone to form oxime e.g. roxithromycin 10 REVOLUTIONPHARMD.COMPowerPoint Presentation: alteration of c-6 hydroxyl group : nucleophilic functionality which initiates erythromycin degradation. The azalides (azithromycin) are semi-synthetic 15-membered congeners in which a nitrogen atom has been introduced to expand a 14-membered precursor- leads to an extended spectrum of action . 11 REVOLUTIONPHARMD.COMPHARMACOKINETIC ASPECTS:: PHARMACOKINETIC ASPECTS: These are administered orally Erythromycin can also be given parenterally, through intravenous injections. These diffuse readily into most tissues but do not cross the BBB & poor penetration into synovial fluid . 12 REVOLUTIONPHARMD.COMTherapeutic Agents Of Macrolides: Erythromycin:: Therapeutic Agents Of Macrolides : Erythromycin : 13 REVOLUTIONPHARMD.COM Source:: Source: Isolated from streptomyces erythreus Physical properties : Yellow to white crystalline powder Soluble in alcohol, slightly soluble in water Stable at neutral PH Dosage forms : Oral and topical dosage forms Enteric coted and delayed realese dosage forms 14 REVOLUTIONPHARMD.COMDrug interactions:: Drug interactions : Anticoagulants Benzodiazepines Cyclosporine Antihistaminic drugs These agents potentiate the action of erythromycin Adverse effects : Abdominalcramps Epigastric distress Jaundice Transient deafness 15 REVOLUTIONPHARMD.COMPowerPoint Presentation: USES: It is used to treat The upper part of the respiratory tract infections, Mycoplasma pneumonia Gonorrhoea. It is a good choice for penicillin-sensitive cases 16 REVOLUTIONPHARMD.COMTherapeutic agents of erythromycin : Therapeutic agents of erythromycin Erythromycin ethylsuccinate Prodrug with more lipophilicity- longer duration of action Erythromycin estolate A lipid soluble,acid stable prodrug with better oral absorption Erythromycin gluceptate A water-soluble salt of glucoheptanoic acid for parentral dosage forms Erythromycin lactobionate Erythromycin salt meant for parentral usage 17 REVOLUTIONPHARMD.COMClarithromycin Clarithromycin Semisynthetic derivative of erythromycin obtained by selective methylation at c-6 position: 6-Methyl ether of erythromycin: Clarithromycin Clarithromycin Semisynthetic derivative of erythromycin obtained by selective methylation at c-6 position: 6-Methyl ether of erythromycin 18 REVOLUTIONPHARMD.COMPowerPoint Presentation: Advantages: Cannot undergo cyclic ketal formation, so doesn’t cause cramp in GI. Higher blood concentrations. More lipophyl. Lower doses with less intervals USES: Effective against Borrelia burgdorferi, mycobacterium aviumcomplex 19 REVOLUTIONPHARMD.COMAzithromycin: Azithromycin Nitrogen containing 15-membered lactone ring macrolides(azalides) Stable under acidic conditions, because it doesn’t form cyclic ketal. 20 REVOLUTIONPHARMD.COMPowerPoint Presentation: USES: In the treatment of urogenital infections caused by N. gonorrhoeae and Chlamydia trachomatis . Widely prescribed for the treatment of respiratory tract infections. More active against gram(-)bacteria. 21 REVOLUTIONPHARMD.COMROXITHROMYCIN: : ROXITHROMYCIN: Semi-synthetic 14-membered ring macrolide antibiotic in which the erythronolide lactone ring has been altered to prevent inactivation in the milieu. 22 REVOLUTIONPHARMD.COMPowerPoint Presentation: USES: Active against both gram(+) & gram(-) Treatment of skin, dental and genital infections Treatment of upper and lower respiratory tract infections. 23 REVOLUTIONPHARMD.COMREFERENCES:: REFERENCES: S.N.Pandeya,Textbook of medicinal chemistry Rama Rao Nadendla,Medicinal chemistry Sri Ram, Medicinal chemistry The Mechanism of Action of Macrolides, and Lovmar and Måns Ehrenberg . Keicho N, Kudoh S (2002). "Diffuse panbronchiolitis: role of macrolides . Lopez-Boado YS, Rubin BK (2008). "Macrolides as immunomodulatory therapeutic agents. Curr Opin Pharmacol. 24 REVOLUTIONPHARMD.COM You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.