Part 6 - Monobactam
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murugadas1985Part 6 - Monobactam
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murugadas1985Approved by PHARMACY COUNCIL OF INDIA – New delhi
Affiliated to THE TAMILNADU DR MGR MEDICAL UNIVERSITY - Chennai
ARUNAI COLLEGE OF PHARMACY - Tiruvannamalai
Prepared & Lecture by
Unit 1 - ANTIBIOTIC Part 6 – MONOBACTAM’S Mr. Murugan
(Associate professor)
MEDICINAL CHEMISTRY-III (BP-601T) - B Pharmacy - VI Sem
Syllabus:
Historical background, Nomenclature, Stereochemistry, Structure activity relationship, Chemical
degradation classification and important products of the following classes.
Monobactams
Pervious university exam question
Sep 2021 Write a note on Monobactam antibiotics (2 mark)
May 2022 Monobactam antibiotic (2 mark)
Monobactams are a subgroup of β-lactam antibiotics, that are monocyclic derivatives produced by various
soil bacteria (sulfazecin - Pseudomonas, nocardicins - Nocardia) and modified synthetically - Aztreonam.
The only commercially available monobactam antibiotic is aztreonam.
Other examples: tigemonam, nocardicin A.
Structure:
It inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins.
Aztreonam is active against aerobic Gram-negative bacteria, and
inactive against Gram-positive bacteria and anaerobics
Used for hospital acquired infections from urinary, biliary, gastrointestinal and female genital tracts
Chemistry: Structurally contain lactam ring
monocyclic derivative ( lactam ring not fused with other ring)
sulfonic acid group attach with N atom in lactam ring
2 position free methyl group is present
4 position free carbonyl group is available
3 position various substitution will take place
SAR:
Mechanism:
Monobactam antibiotic inhibit the bacterial cell wall synthesis by interfering with the transpeptidation,
covalently bind to penicillin binding protein (PBP) in aerobic gm –ve bacteria to prevent growth of the
cell wall via peptidoglycan synthesis.
Spectrum of activity
Limited to aerobic gram –ve bacteria
Excellent activity against Enterobacteriaceae incl. E.coli, K. pneumoniae
No activity against gram +ve bacteria and anaerobes
Uses: Safe in patients, unable to tolerate penicillin or cephalosporine.
Mycobacterial disease, Gram –ve sepsis
Pneumoia, Meningitis, Endometritis
Bone infections, Urinary tract infection and abdominal infections
Common side effects: Nausea, vomiting, diarrhea, abdominal pain, skin rash etc.
Aztreonam Acts by binding to specific Penicillin The main indications of
Novel Monobactam β-lactam antibiotic Binding Proteins (PBPs) aztreonam are hospital
Totally synthetic parenteral antibiotic Exclusively active towards aerobic acquired infections from
gram-ve microorganisms, urinary, biliary,
low concentrations: inhibits gram-ve gastrointestinal and female
bacilli and H.influenzae genital tracts
moderate concentrations: inhibits
Pseudomonas
Tigemonam highly resistant to β-lactamases. valuable agent for the oral
Newer monobactam orally active. very active against treatment of UTI and other
oral absorption is excellent Enterobacteriaceae, including E. coli, non–life-threatening
Klebsiella, Enterobacter. infections caused by beta-
exhibits good potency against H. lactamase–producing Gram-
influenzae and N.gonorrhoeae. negative bacteria