2. CONTENTS
• Introduction
• Chemical characteristics of macrolide antibiotics
• Classification of macrolide antibiotics
• Mechanism of action of Macrolides
• Erythromycin
• Azithromycin
• Marketed products of macrolide antibiotics
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3. INTRODUCTION
• The term macrolide is used to describe compounds with a macro cyclic lactone ring of 12
or more elements.
• Compounds with large macro cyclic lactone ring( 14-16 membered) which have one or
more deoxy sugars are called Macrolide antibiotics.
• Macrolides are the class of natural and semisynthetic products that consist of a large 14 to
16 membered lactone ring with deoxy sugars like cladinose and desosamine.
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5. CHEMICAL CHARACTERISTICS OF MACROLIDES
• A large lactone ring usually a macro cyclic ring with 12-16 atoms in it.
• A ketone group at 9th position.
• A glycosidically linked amino sugar.
• Because of the dimethyl amino sugar moiety, the drugs are bases that forms salts
with pKa values 6.0-9.0 which is used to make clinically useful salts.
• They are stable in aqueous but they get inactivated in bases, acids and heat.
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7. MECHANISM OF ACTION OF MACROLIDEANTIBIOTICS
• They inhibit protein synthesis by irreversibly
binding to P site on 50s subunit of bacterial
ribosomes.
• Thus inhibiting the translocation steps of
protein synthesis at stages of peptide chain
elongation.
• This results in the inhibition of bacterial
growth and the eventual death of the
bacterium.
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9. • Erythromycin is widely used as a substitute to penicillin in cases where
patients were allergic to penicillin or had penicillin-resistant illnesses.
• Erythromycin is bacteriostatic.
Uses:
1. Diphtheria.
2. Chlamydia.
3. Commonly acquired pneumonia.
4. Ear infections in children.
5. Dental abscesses.
6. Sexually transmitted infections.
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11. AZITHROMYCIN
• It is a semi synthetic of Erythromycin.
• Azithromycin is a prototype of azalides.
• It is more active against chlamydial infection.
• It is broad spectrum and 15 membered ring with nitrogen.
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14. SAR OF MACROLIDE ANTIBIOTICS
• A lactone ring, ketonic group and an
amino sugar are the basic characteristic
groups that are desired for activity.
• Dimethyl amino group provides basic
properties to macrolides Lactone ring
contains 12, 14, 16 atoms in cyclic ring.
• Reduction at C-9 results in more stable
product but is less potent.
• Modification at C-8 leads to the acidic
stability.
• 11, 12 - carbonate were prepared which
were more stable and had double
activity but had hepatotoxic potential.
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15. • Removal of hydroxyl group at C-6 leads to decrease in potency.
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